United States 

Department of 

Agriculture

Marketing and 

Regulatory 

Programs

Animal and 

Plant Health 

Inspection 

Service

Cattle Fever Tick 

Eradication Program – 

Tick Control Barrier

Maverick, Starr, Webb, and 

Zapata Counties, Texas 

Draft Environmental Impact 

Statement—June 2013

Cattle Fever Tick Eradication 

Program – Tick Control Barrier

Maverick, Starr, Webb, and Zapata 

Counties, Texas

Draft Environmental Impact Statement—

June 2013

Agency Contact:

Matthew T. Messenger

Staff Entomologist

Cattle Fever Tick Eradication Program Manager

Veterinary Services

Animal and Plant Health Inspection Service

U.S. Department of Agriculture

4700 River Road, Unit 43

Riverdale, MD 20737
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Table of Contents

Page

Legal Authorities......................................................................................................................viii

List of Abbreviations and Acronyms................................................................................... xi

Executive Summary.............................................................................................................xiii

Chapter 1

I. Purpose and Need............................................................................................................ 1

A. Federal Agency Mission and Relation to the Proposed Action

 Examined in This Document...................................................................................... 1 

B. National Environmental Policy Act and the Proposed Action

 Examined in This Document...................................................................................... 1 

 Why did APHIS prepare an environmental impact statement (EIS)?............................. 1 

 How was the public involved in the scoping process for this draft EIS? ........................ 3 

 How and why is APHIS making the Draft EIS available for public comment?................ 4 

C. Background Information Related to the Proposed Action ...................................... 5 

What is the proposed action and why is the action being proposed?............................ 5 

Why are the ticks a concern? ....................................................................................... 5 

What is the history of U.S. efforts taken against these ticks?........................................ 8 

What has changed?....................................................................................................14

 White-tailed Deer..................................................................................................14

Success of Fencing ..............................................................................................14

Hunter Involvement...............................................................................................15

Cattle Fever Tick Infestations ...............................................................................17

What are the factors related to the control of cattle fever ticks?..................................19

 Wildlife..................................................................................................................19

 Climate and Weather............................................................................................24

 Cattle Fever Ticks and Acaricide Resistance........................................................25

 Funding ................................................................................................................26

 Cost of Cattle Fever Tick Spread.......................................................................... 26 

II. Purpose and Need for the Proposed Action................................................................. 27

Chapter 2

II. Alternatives .................................................................................................................... 31 

A. No Action: Continue to conduct current program operations

 without installing game fencing .............................................................................. 31 

 1. Livestock Program Activities in the Permanent Tick Quarantine Zone .................. 31 

 2. Treatment of White-tailed Deer and Exotic Ungulates on Infested Premises......... 35 

 3. Treatment of Imported Cattle from Mexico............................................................ 36 

i 
B. Proposed Action: Provide funding assistance to install game

 fencing in areas of need........................................................................................... 36 

1. General Location of Game Fencing ...................................................................... 36 

 2. Specific Placement of Game Fencing ...................................................................38

 3. Details of Game Fence Installation .......................................................................40

 4. Maintenance of Game Fencing............................................................................. 42 

C. Other Alternatives Considered but Dismissed.......................................................42

 1. Provide funding for game fencing in contiguous placement along the 

 TAHC Quarantine Line ......................................................................................... 43 

 2. Provide game fencing along the entire 500 miles of the Permanent

 Tick Quarantine Line............................................................................................. 44 

 3. Locate the proposed tick control barrier game fencing in the right-of-way

 in the proposed locations along U.S. Hwy 83 versus on privately

 owned land ...........................................................................................................44

 4. Use other tick control measures or technologies in addition to

 game fencing........................................................................................................44

 5. Coordinate game fencing efforts with other agencies............................................45

 6. Coordinate tick control barrier game fencing effort with CBP efforts ..................... 46 

 7. Work with Federal and State agencies in Mexico..................................................46

 8. Implement white-tailed deer and exotic deer population control

 with a vaccine.......................................................................................................46

Chapter 3

III. Affected Environment....................................................................................................49

A. Cattle Fever Tick Resistance and Distribution.......................................................49

B. Land Resources and Characteristics......................................................................50

 1. Maverick County...................................................................................................51

 2. Starr County .........................................................................................................52

 3. Webb County........................................................................................................52

 4. Zapata County......................................................................................................53

C. Climate ......................................................................................................................54

D. Air Quality.................................................................................................................54

E. Water Quality ............................................................................................................59

1. Arroyos/Streams with Defined Channels...............................................................61

 2. Arroyos/Streams without Defined Channels..........................................................62

 3. Jurisdictional Wetlands .........................................................................................62

 4. Open Water .......................................................................................................... 62 

 5. Isolated Features..................................................................................................63

F. Vegetation.................................................................................................................63

 1. Current Restoration Activities ...............................................................................65

 2. Invasive Vegetation ..............................................................................................67

G. Wildlife ......................................................................................................................69

 1. Birds .....................................................................................................................70

 2. Big Game Species................................................................................................70

ii
 3. Non-native Species...............................................................................................71

 4. Threatened and Endangered Species...................................................................72

H. Human Health and Safety ........................................................................................75

 1. Environmental Justice...........................................................................................75

 2. Colonias ............................................................................................................... 76 

 3. Schools.................................................................................................................77

 4. Socioeconomics ...................................................................................................77

I. Cultural, Historic, and Visual Resources................................................................78

Chapter 4

IV. Environmental Consequences ......................................................................................81

A. Land Resources and Characteristics......................................................................81

 1. No Action Alternative ............................................................................................82

 2. Proposed Action Alternative..................................................................................82

 3. Potential Mitigation Measures...............................................................................85

B. Climate ......................................................................................................................85

 1. Impacts Common to Both Alternatives ..................................................................85

 2. No Action Alternative ............................................................................................86

 3. Proposed Action Alternative..................................................................................86

C. Air Quality.................................................................................................................88

 1. Clean Air Act.........................................................................................................88

 2. No Action Alternative ............................................................................................88

 3. Proposed Action Alternative..................................................................................88

 4. Potential Mitigation Measures...............................................................................90

D. Water Quality ............................................................................................................90

 1. Clean Water Act ...................................................................................................90

 2. Texas Pollutant Discharge Elimination System.....................................................90

 3. Executive Order 11988 – Floodplain Management ...............................................90

 4. Executive Order 11990 – Protection of Wetlands.................................................. 91 

 5. No Action Alternative ............................................................................................91

 6. Proposed Action Alternative..................................................................................91

 7. Potential Mitigation Measures...............................................................................93

E. Livestock Health.......................................................................................................93

 1. Disease Transmission between Feral or Wild Animals and Livestock ...................95

 2. No Action Alternative ............................................................................................97

 3. Proposed Action Alternative..................................................................................98

 4. Potential Mitigation Measures...............................................................................99

F. Vegetation...............................................................................................................100

 1. Noxious Weed and Invasive Species Concerns..................................................100

 2. Potential Environmental Consequences .............................................................103 

 3. Endangered Species Act ....................................................................................103 

 4. No Action Alternative ..........................................................................................104

 5. Proposed Action Alternative................................................................................104 

 6. Potential Mitigation Measures.............................................................................105 

iii
G. Wildlife ....................................................................................................................106

 1. Migratory Bird Treaty Act ....................................................................................107

 2. Executive Order 13186 – Responsibilities of Agencies to Protect

 Migratory Birds ..................................................................................................107

 3. Bald and Golden Eagle Protection Act................................................................107 

 4. Endangered Species Act ....................................................................................108

 5. No Action Alternative ..........................................................................................110

 6. Proposed Action Alternative................................................................................111

 7. Potential Mitigation Measures.............................................................................113

H. Human Health and Safety ......................................................................................113 

 1. Executive Order 13045 – Protection of Children from Environmental Health

 Risks and Safety Risks .......................................................................................114

 2. Executive Order 12898 – Federal Actions to Address Environmental Justice in 

Minority Populations and Low-income Populations .............................................114

 3. Impacts Common to Both Alternatives ................................................................114 

 4. No Action Alternative ..........................................................................................116

 5. Proposed Action Alternative................................................................................116 

 6. Potential Mitigation Measures.............................................................................119

I. Cultural, Historic, and Visual Resources.............................................................. 119

 1. Archaeological Resources Protection Act ...........................................................120

 2. Native American Graves Protection and Repatriation Act and 

 Executive Order 13045 .......................................................................................120

 3. No Action Alternative ..........................................................................................120 

 4. Proposed Action Alternative................................................................................120 

 5. National Historic Preservation Act Consultation ..................................................121 

 6. Tribal Consultation..............................................................................................123

 7. Protection of Children .........................................................................................123 

 8. Potential Mitigation Measures.............................................................................124

J. Other Considerations.............................................................................................124 

 1. Executive Order 13166 – Improving Access to Services for Persons with

 Limited English Proficiency .................................................................................124 

 2. Farmland Protection Policy Act...........................................................................124 

 3. National Wild and Scenic Rivers Act...................................................................125 

 4. Irreversible and Irretrievable Commitment of Resources.....................................125 

K. Cumulative Impacts................................................................................................127 

 1. Human Population ..............................................................................................128 

 2. Ecological Resources .........................................................................................129 

 3. Environmental Quality......................................................................................... 131

 4. Conclusion..........................................................................................................132 

Appendices

A. List of Preparers............................................................................................................. A-1 

B. Review and Consultation................................................................................................ B-1 

iv
C. Summary of and Responses to Comments on Draft EIS (provided in Final EIS)

D. Distribution List............................................................................................................... D-1 

E. References Cited ........................................................................................................... E-1 

F. Acronyms and Glossary ................................................................................................. F-1 

G. Index (provided in Final EIS)

H. Maps of Proposed Fence Segments .............................................................................. H-1 

I. Water Resources ............................................................................................................. I-1 

J. Socioeconomics .............................................................................................................. J-1 

K. Historic and Cultural Information .................................................................................... K-1 

Figures

1-1. Cattle fever tick life stages............................................................................................ 7 

1-2. Early 1900s range of cattle fever ticks and southern cattle ticks

in the United States ...................................................................................................... 9 

1-3. Map of the Permanent Tick Quarantine Zone and Permanent Tick Quarantine

Line within eight Texas counties.................................................................................11

1-4. Double fences remain years later after the CFTEP 1965 double fence

effort to move the quarantine zone closer to the Rio Grande......................................13

1-5. High fencing project in Maverick County showing infested and exposed

pastures to cattle fever ticks before construction of the high fence along the

Permanent Tick Quarantine Line in 1984, and after construction of the

high fencing surrounding the entire property located in the Permanent

Tick Quarantine Zone (1996-2009).............................................................................16

1-6. Cattle fever tick infestations in Texas by fiscal year, October 1, 1959 – 

September 30, 2011...................................................................................................18

1-7. Locations of cattle fever tick infestations during fiscal year 2004 (October 1, 2003

through September 30, 2004).....................................................................................20

1-8. Locations of cattle fever tick infestations during fiscal year 2005 (October 1, 2004

through September 30, 2005).....................................................................................20

1-9. Locations of cattle fever tick infestations during fiscal year 2006 (October 1, 2005

through September 30, 2006).....................................................................................21

1-10. Locations of cattle fever tick infestations during fiscal year 2007 (October 1, 2006

through September 30, 2007).....................................................................................21

v 
1-11. Locations of cattle fever tick infestations during fiscal year 2008 (October 1, 2007

through September 30, 2008).....................................................................................22

1-12. Locations of cattle fever tick infestations during fiscal year 2009 (October 1, 2008

through September 30, 2009).....................................................................................22

1-13. Locations of cattle fever tick infestations during fiscal year 2010 (October 1, 2009

through September 30, 2010).....................................................................................23

1-14. Locations of cattle fever tick infestations during fiscal year 2011 (October 1, 2010

through September 30, 2011).....................................................................................23

1-15. CFTEP annual number of cattle inspected in both Permanent Tick Quarantine

Zone and Tick-free Area, 1993-2011 ..........................................................................30

1-16. CFTEP annual number of cattle inspected in Permanent Tick Quarantine Zone 

(Systemic) and Tick-free Areas, 1993-2011................................................................30

2-1. Example of wire-knot game fencing............................................................................40

2-2. Low fence with a high game fencing extension...........................................................41

3-1. Average temperature and precipitation in South Texas, 1971-2000............................55

3-2. Global satellite-derived map of the fine particulate matter (PM2.5) from

2001-2006 ..................................................................................................................57

3-3. TCEQ Air Quality Control Areas .................................................................................59

3-4. Ecoregions of Texas, as described by R.G.Bailey (1995)...........................................64

3-5. Map depicting the distance between the nearest star cactus restoration

site and the location of the proposed fence ................................................................67

Tables

1-1. Cattle fever tick infestations in the Permanent Tick Quarantine

Zone and Tick-free Area of South Texas (2001-2011)................................................17

3-1. Primary and secondary national ambient air quality standards

(40 CFR § 50).............................................................................................................56

3-2. Jurisdictional and non-jurisdictional water bodies along the proposed

fencing area ...............................................................................................................60

vi
3-3. Water bodies in 100-year floodplain ...........................................................................62

3-4. Predominant plants of the ceniza-blackbrush-creosote (C-B-C) and

mesquite-blackbrush (M-B) communities....................................................................66

3-5. List of exotic invasive plant species known to inhabit Maverick, Starr,

Webb, and Zapata Counties, Texas ...........................................................................69

3-6. State-listed species in Maverick, Starr, Webb, and Zapata Counties ..........................73

3-7. Species of concern in Maverick, Starr, Webb, and Zapata Counties...........................74

4-1. Soil series identified in Maverick (M), Starr (S), Webb (W), and 

Zapata (Z) Counties....................................................................................................83

vii
Legal Authorities

Federal Acts

• Animal Health Protection Act of 2002, as amended (AHPA) (Public Law (P.L.) 

107-171; 7 United States Code (U.S.C.) §§ 8301-8317).

• Archeological Resources Protection Act of 1979, as amended (ARPA) (P.L. 86-

95, 16 U.S.C. §§ 470aa-mm).

• Bald and Golden Eagle Protection Act of 1940, as amended (BGEPA) (P.L. 86-

70, 16 U.S.C. §§ 668-668d.)

• Clean Air Act of 1963, as amended (CAA) (P.L. 88-206, 42 U.S.C. §§ 7401-

7661).

• Clean Water Act of 1972, as amended (CWA) (P.L. 92-500, 33 U.S.C. §§ 1251-

1387).

• Endangered Species Act of 1973, as amended (ESA) (P.L. 93-205; 16 U.S.C. 

§§ 1531-1544). 

• Farmland Protection Policy Act of 1981, as amended (FPPA) (P.L. 97-98, 7 

U.S.C. §§ 4201-4209).

• Federal Insecticide, Fungicide, and Rodenticide Act of 1947, as amended 

(FIFRA) (P.L. 80-104, 7 U.S.C. §§ 136-136y).

• Migratory Bird Treaty Act of 1918, as amended (MBTA) (16 U.S.C. 703-712). 

• National Environmental Policy Act of 1969, as amended (NEPA) (P.L. 91-190, 42 

U.S.C. §§ 4321-4347.

• National Historic Preservation Act of 1966, as amended (NHPA) (P.L. 89-665; 16 

U.S.C. §§ 470 et seq.).

• National Wild and Scenic Rivers Act of 1968, as amended (NWSRA) (P.L. 90-

542, 16 U.S.C. §§ 1271-1287).

• Native American Graves Protection and Repatriation Act of 1990 (NAGPRA) 

(P.L. 101-601, 25 U.S.C. §§ 3001-3013).

• Plant Protection Act of 2000 (PPA) (P.L. 106-224, 7 U.S.C. §§ 7701-7786).

Executive Orders

• Executive Order (EO) 11988, Floodplain Management, issued on May 24, 1977.

• EO 11990, Protection of Wetlands, issued on May 24, 1977.

• EO 12898, Federal Actions to Address Environmental Justice in Minority 

Populations and Low-income Populations, issued on Feb. 11, 1994.

• EO 13007, Indian Sacred Sites, issued on May 24, 1996.

• EO 13045, Protection of Children from Environmental Health Risks and Safety 

Risks, issued on Apr. 21, 1997.

• EO 13112, Invasive Species, issued on Feb. 3, 1999.

• EO 13166, Improving Access to Services for Persons with Limited English 

Proficiency, issued on Aug. 11, 2000.

viii
• EO 13186, Responsibilities of Federal Agencies to Protect Migratory Birds, 

issued on Jan. 10, 2001.

Code of Federal Regulations

• Determinations of Eligibility for Inclusion in the National Register of Historic 

Places (36 Code of Federal Regulations (CFR) § 63).

• Endangered and Threatened Plants (50 CFR § 17.12).

• Interagency Cooperation – Endangered Species Act of 1973, as amended 

(50 CFR § 402)

• Introduction, Definitions (50 CFR § 22.3).

• Migratory Bird Permits (50 CFR § 21).

• National Environmental Policy Act Implementing Procedures (7 CFR § 372 

(1995)).

• National Primary and Secondary Ambient Air Quality Standards (40 CFR § 50).

• Occupational Safety and Health Administration Regulations (29 CFR §§ 1910 et 

seq.).

• Office of the Secretary of Agriculture Administrative Regulations (7 CFR §§ 1b, 

2.22(a)(8), 2.80(a)(30)).

• Protection of the Environment (40 CFR §§ 122-503).

• National Pollutant Discharge Elimination System (40 CFR §§ 122-503).

• Protection of Historic Properties, as amended (36 CFR §§ 800 et seq.).

• Section 404(b)(1) Guidelines for Specification of Disposal Sites for Dredged or 

Fill Material, as amended (40 CFR § 230).

• Water Quality Standards Regulation, as amended (40 CFR § 131).

• 404 Program Definitions; Exempt Activities Not Requiring 404 Permits, as 

amended (40 CFR § 232).

• 404 State Program Regulations, as amended (40 CFR § 233).

• Regulations for Implementing the Procedural Provisions of the NEPA (40 CFR

§§ 1500-1508 (1978)).

• Texas (Splenetic) Fever in Cattle, as amended (9 CFR § 72).

Federal Register

• Endangered and Threatened Wildlife and Plants; Determination of Endangered 

Status for the Plant Astrophytum asterias (Star cactus) (58 Federal Register (FR) 

53804-53807 (1993) (50 CFR § 17)).

• Proposed Cattle Fever Tick Control Barrier in South Texas; Environmental 

Impact Statement (76 FR 8709 (2011)).

ix
Texas Legislation

• Texas Clean Air Act of 1989, as amended (Texas Health and Safety Code 

(THSC) Chapter 382).

• Environmental Quality – Air Permitting (30 Texas Administrative Code (TAC) 

§§ 101-122 (1996, as amended)).

• Fever Ticks (4 TAC §§ 41.1-41.22 (2002, as amended)). 

• Noxious and Invasive Plants (4 TAC §19.300 (2005, as amended)).

• Texas Pollutant Discharge Elimination System (30 TAC §§ 305.533, 305.541).

• Texas Invasive Species Coordinating Committee, Definitions (Texas Government 

Code § 776.001).

• Estrays and Livestock (6 Texas Agriculture Code §§ 142-143).

• General Disease and Pest Control, Definitions (Texas Agriculture Code 

§ 161.001(a)).

• Tick Eradication (6 Texas Agriculture Code § 167).

x 
List of Abbreviations and Acronyms:

AHPA Animal Health Protection Act

APHIS Animal and Plant Health Inspection Service

ARPA Archaeological Resources Protection Act

BGEPA Bald and Golden Eagle Protection Act

CAA Clean Air Act

CAFO Concentrated Animal Feeding Operation

CBP Customs and Border Patrol

CEQ Council on Environmental Quality

CFR Code of Federal Regulations

CFSPH Center for Food Security and Public Health

CFTEP Cattle Fever Tick Eradication Program

CO Carbon Monoxide

CO2 Carbon Dioxide

CWA Clean Water Act

EA Environmental Assessment

EIS Environmental Impact Statement

EO Executive Order

EPA Environmental Protection Agency

ESA Endangered Species Act

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FPPA Farmland Protection Policy Act

FR Federal Register

FWHA U.S. Federal Highway Administration

FWS U.S. Fish and Wildlife Service

IBWC International Boundary and Water Commission, United States Section

MBTA Migratory Bird Treaty Act

MDNR Michigan Department of Natural Resources

NABCI North American Bird Conservation Initiative

NAGPRA Native American Graves Protection and Repatriation Act

NAS National Audubon Society

NEPA National Environmental Protection Act

NHPA National Historic Preservation Act

NOx Oxides of Nitrogen

NO2 Nitrogen Dioxide

NRCS Natural Resources Conservation Service

NWSRA National Wild and Scenic Rivers Act

O3 Ozone

Pb Lead

xi
PM2.5 Particulate Matter <2.5 Micrometers

PM10 Particulate Matter <10 Micrometers

PPA Plant Protection Act

SAGARPA Secretaría de Agricultura, Ganadería, Desarollo Rural, Pesca Y 

Alimentación (SAGARPA, or Ministry of Agriculture, Livestock, Rural 

Development, Fishing, and Food)

SO2 Sulfur Dioxide

TAC Texas Administrative Code

TAHC Texas Animal Health Commission

TAMU Texas A&M University

TB Tuberculosis

TCEQ Texas Commission on Environmental Quality

TCPS Texas Center for Policy Studies

TEA Texas Education Agency

THSC Texas Health and Safety Code

TIPPC Texas Invasive Plant and Pest Council

TISCC Texas Invasive Species Coordinating Committee

TPWD Texas Parks and Wildlife Department

TSHA Texas State Historical Association

TSSWCB Texas State Soil and Water Conservation Board

TXDOT Texas Department of Transportation

TXRC Texas Railroad Commission

U.S.C. United States Code

USDA United States Department of Agriculture

VOC Volatile Organic Compound

xii
Executive Summary

In this Draft Environmental Impact Statement, APHIS analyzes the 

environmental effects associated with a proposal to enhance the 

eradication effort against cattle fever ticks in South Texas. The proposed 

action is installation of approximately 70 miles of non-contiguous game 

fencing under agreements for cost-sharing with landowners. Recurrent 

cattle fever tick outbreaks are increasing in locations either within the 

Permanent Tick Quarantine Zone or outside of the zone in the cattle fever 

tick-free area of South Texas. The proposed fence would help prevent reinfestation of areas where the pest has been or is being eliminated. 

Cattle fever ticks are agricultural pests of concern for U.S. livestock 

because they can cause devastating economic loss. If there was an 

extended tick outbreak, the overall economic impact, including control 

costs, is estimated to exceed $1.2 billion. These ticks reduce animal 

productivity by feeding on blood and inducing anemia. Ticks also spread 

protozoan parasites that cause disease. Symptoms of the tick-borne disease 

babesiosis include anemia, weight loss, and neurological disturbances. 

Since bovine babesiosis was eradicated from the United States in 1943, 

there has been no need to vaccinate cattle against the disease. All U.S. 

herds are considered “naïve hosts” because they have not been exposed or 

vaccinated to ticks and the diseases they carry. Consequently, U.S. cattle 

are more susceptible to extreme illness if infected. 

There is strong evidence that stray or smuggled livestock and wildlife, 

such as white-tailed deer, play a role in the spread of cattle fever ticks. 

When these free-ranging animals enter pastures, the effectiveness of other 

ongoing tick eradication measures (such as vacating pastures and 

systematic tick treatments for cattle) becomes compromised. These tick 

hosts increase the potential for cattle fever ticks and disease to spread. 

Game fences ultimately contribute another tool toward cattle fever tick 

eradication and prevention efforts.

xiii
Summary of Alternatives

No Action Alternative

Under the No Action Alternative, APHIS would continue current program 

operations for cattle that help prevent the spread of ticks and potential 

exposure to disease. These activities include inspection of livestock, 

patrols for stray or smuggled livestock, vacating premises, and pesticide 

treatment on tick-host livestock (primarily cattle and horses) on 

quarantined premises. 

Proposed Action Alternative

The Proposed Action Alternative would provide a cost-share toward 

installation of game fences, in areas with landowner consent, along the 

Permanent Tick Quarantine Line in four counties in Texas (Maverick, 

Starr, Webb, and Zapata Counties). The properties proposed for game 

fences are privately owned lands in rural locations and are primarily used 

for cattle ranching. APHIS proposes to provide a one-time APHIS costshare with property owners; costs are expected to be $22,000 per mile of 

game fencing. APHIS would contract with landowners, and terms would 

ensure compliance with various aspects of the law. In areas where 8-foot 

game fencing already exists near and is parallel to the Permanent Tick 

Quarantine Line, this proposed fencing would connect with the existing 

fencing. The majority of the proposed fence locations border U.S. 

Highway 83. 

Environmental Impacts 

No Action Alternative

Impacts associated with the No Action Alternative arise as a consequence 

of ecological processes progressing over time. The primary impact is that 

introductions of ticks into new areas could lead to devastating and 

widespread outbreaks of disease in the U.S. cattle population. Outbreaks 

are projected to be met with increased use of pesticides, which are 

associated with increasing tick resistance. Because these pesticides are the 

same compounds as those currently used in northeastern Mexican States, 

eradication efforts are less likely to be successful over time. This leads to 

concerns about pesticide-resistant tick populations becoming established 

xiv
in the United States. With climate change occurring, favorable vegetation 

is expected to shift north across the country. These changes could further 

increase the potential for unrestricted tick spread in white-tailed deer 

populations, including stray native and exotic deer. 

Beneficial impacts associated with this alternative include keeping intact 

the long-term connectivity of ocelot and jaguarundi populations between 

Mexico and Texas. Competition among native threatened or endangered 

plants and invasive species is not likely to occur as a consequence of the 

movement of construction equipment and soil disturbance. 

Proposed Action Alternative

The potential effects on the quality of the human environment during 

construction of fence segments would involve transient and minimal 

impacts to soil, climate, air, water, vegetation, and local residents along 

the corridor of installation. These impacts would arise from site clearing, 

soil erosion, and stormwater runoff as the fence is installed. The continued 

presence of game fence segments (post construction) is not expected to 

alter land use, permanently impact water use or drainage (including 

floodplains and wetlands), or have visual impacts. Limited inadvertent 

dispersal of invasive species could occur during construction. 

The proposed fencing has the potential to impact federally listed 

threatened and endangered species in South Texas; therefore, APHIS is 

engaged in formal consultation with the U.S. Fish and Wildlife Service. 

Fence construction under this alternative would not occur until this 

consultation is complete. 

Livestock would benefit from game fencing by reducing the likelihood of 

disease transmission from wildlife. The game fence segments may impact 

wildlife by hindering access to forage and water resources during seasonal 

migration. Wildlife also has the potential to collide with or become 

ensnared in the fencing. 

Increased cattle fever tick eradication efforts are essential to prevent tick 

reestablishment and disease outbreaks. Outbreaks would lead to increased 

use of pesticides, the development of pesticide-resistant strains, increased 

control costs, and quarantines throughout the county. The use of game 

fences as an additional tool against cattle fever tick re-infestation would 

xv
reduce the economic burden that extends to the U.S. government and 

taxpayers by reducing the potential for pest entry. The proposed fence is 

expected to create a minimally intrusive pest control measure that 

augments existing programs. 

xvi
I. Purpose and Need

A. Federal Agency Mission and Relation to the 

Proposed Action Examined in This Document 

The United States Department of Agriculture (USDA), Animal and Plant 

Health Inspection Service (APHIS), Veterinary Services protects and 

improves the health, quality, and marketability of U.S. animals, animal 

products, and veterinary biologics by (1) preventing, controlling, and/or 

eliminating animal diseases and (2) monitoring and promoting animal 

health and productivity. Veterinary Services derives its mission from the 

AHPA (7 U.S.C. §§ 8301-8317). 

APHIS received emergency funding in 2009 for an enhanced eradication 

effort against the cattle fever tick in Texas. The ticks threaten animal 

health by spreading a severe and often fatal disease of cattle. As part of the 

continued enhanced eradication effort for this disease-spreading pest, 

APHIS requested funding to install game fencing in rural areas of cattle 

production where recurrent cattle fever tick outbreaks continue to occur in 

locations either within the Permanent Tick Quarantine Zone or outside of 

the zone in the cattle fever tick-free area of South Texas. The fence would 

help prevent re-infestation of areas where the pest has been or is being 

eliminated. 

The Permanent Tick Quarantine Zone is an approximately 580-mile-long 

stretch of land from Del Rio to Brownsville, Texas, ranging in width from 

almost 125 yards (0.07 miles) to approximately 8 miles. The Permanent 

Tick Quarantine Line defines the boundary between the Permanent Tick 

Quarantine Zone and the tick-free area and is defined in regulations 

enforced by the Texas Animal Health Commission (TAHC) whose 

mission includes cattle fever tick eradication for protecting livestock 

health in Texas. This line runs along the existing roads and highways near 

the U.S./Mexico border through eight South Texas counties (Val Verde, 

Kinney, Maverick, Webb, Zapata, Starr, Hidalgo, and Cameron). 

B. National Environmental Policy Act and the 

Proposed Action Examined in This Document 

Why did APHIS prepare an environmental impact statement (EIS)? 

1
As a Federal Government agency subject to compliance with NEPA 

(42 U.S.C. 4321-4347), APHIS prepared this EIS in accordance with the 

applicable implementing and administrative regulations (40 CFR §§ 1500-

1508; 7 CFR §§1b, 2.22(a)(8), 2.80(a)(30), 372). APHIS will consider 

potential significant environmental effects on the quality of the human 

environment1

 caused by providing a cost share toward installation of game 

fencing by landowners in four of the counties (Maverick, Starr, Webb, and 

Zapata Counties) along the Permanent Tick Quarantine Line. The intent of 

game fencing is to help prevent the spread of cattle fever ticks to U.S. 

cattle populations from free-ranging tick hosts, such as stray or smuggled 

livestock from Mexico and wildlife ungulates (hoofed animals), including 

white-tailed deer. The fencing would ultimately contribute another tool 

towards eradication and control efforts. 

Although APHIS began preparing an environmental assessment (EA) for 

the fencing,2

 the CEQ NEPA implementing regulations provide that one 

of the factors that renders an action “significant” is the presence of a 

federally listed threatened or endangered species or its critical habitat, 

according to the ESA (16 U.S.C. §§ 1531-1544). While the EA was 

underway, APHIS confirmed that the scope of the proposed action would 

extend to potential effects on threatened and endangered species and/or 

critical habitat in some locations and potentially to other factors as 

described in the CEQ NEPA regulations (40 CFR § 1508.27). Therefore, 

APHIS determined a need to examine the significance (context) and the 

severity of the impact (extent) on federally listed threatened and 

endangered species and on other factors from building the fence. APHIS 

prepared and is making available for public comment this Draft EIS on the 

proposed fence to examine the full scope of effects, both short- and longterm, and the intensity of the impact on the human environment from the 

following factors: 

• impacts that may be both beneficial and adverse, 

• the degree to which the proposed action affects human health or 

safety, 

1

 The “human environment” is interpreted comprehensively to include the natural and physical 

environment and the relationship of people with that environment (40 CFR § 1508.14).

2

 APHIS’ NEPA Implementing Procedures classify actions seeking to remedy specific animal health 

risks as actions normally requiring preparation of environmental assessments (7 CFR § 372.5(b)(1)).

2

 
• unique characteristics of the geographic area such as proximity to 

historic or cultural resources, prime farmlands, wetlands, wild and 

scenic rivers, or ecologically critical areas, 

• the degree to which the effects on the quality of the human 

environment are likely to be highly controversial, 

• the degree to which the possible effects on the human environment 

are highly uncertain or involve unique or unknown risks, 

• whether the action is related to other actions with individually 

insignificant but cumulatively significant impacts, 

• the degree to which the action may adversely affect districts, sites, 

highways, structures, or objects listed in or eligible for listing in 

the National Register of Historic Places or may cause loss or 

destruction of significant scientific, cultural, or historical 

resources, and 

• the degree to which the action may adversely affect an endangered 

or threatened species or its habitat that has been determined to be 

critical under the ESA. 

How was the public involved in the scoping process for this Draft EIS? 

Scoping is an open and early process for determining the scope of the 

issues to be addressed and for identifying the significant issues related to a 

proposed action in the EIS. Public scoping is required under CEQ NEPA 

regulations. Scoping for this EIS began on February 15, 2011, when 

APHIS gave notice of its intent (76 FR 8709) to prepare an EIS for the 

proposed tick control barrier in South Texas. The notice stated that the 

following issues would be discussed in the EIS: 

• Effects on wildlife, including consideration of migratory bird 

species and changes in native wildlife habitat and populations. 

• Effects on federally listed threatened and endangered species.

• Effects on the soil, vegetation, and water from the installation of 

game fencing.

• Effects on local residents, including impacts on daily activities.

• Effects on human health and safety in the proposed tick barrier 

locations during and after the installation of game fencing. 

• Effects on cultural and historic resources. 

The notice solicited public involvement in the form of either oral or 

written comments on the proposed fence installation. A total of 96 people 

3
attended four public scoping meetings held by APHIS in South Texas in 

2011: March 7 in Rio Grande City; March 8 in Zapata; March 9 in Laredo; 

and March 10 in Eagle Pass. A Spanish translator was available at each 

meeting. APHIS received numerous comments in addition to questions 

from meeting attendees. We also invited public comments through the 

Federal eRulemaking portal at www.regulations.gov, and Postal mail or 

commercial delivery to APHIS in Riverdale, Maryland. We received 10 

comments via the regulations.gov web site. Main issues raised by 

commenters included the location of the tick barrier; coordination of tick 

control efforts with other agencies; impacts of the fence on wildlife, 

ranchers, hunters, and residents of colonias; and efficacy of the tick 

barrier. APHIS has posted a summary of the scoping comments on the 

web page for this EIS at 

http://www.aphis.usda.gov/animal_health/animal_diseases/tick/. 

In addition to the scoping notice, APHIS provided outreach opportunities 

for stakeholders to receive information about the proposed tick barrier, 

scoping process, and public meetings. These include: 

• Web page for the CFTEP Tick Control Barrier EIS. 

http://www.aphis.usda.gov/animal_health/animal_diseases/tick/. 

• Letters to Federal, State, and local public agencies, such as: 

USDA; U.S. Fish and Wildlife Service; U.S. Department of 

Homeland Security; U.S. Army Corps of Engineers; Texas Parks 

and Wildlife; Office of the Texas Secretary of State, including 

the Colonia Initiatives Program; Texas Farm Services Agency; 

Texas Animal Health Commission; County Commissioners’ 

Courts; Texas Department of Transportation; Texas Rural 

Development; Texas Commission on Environmental Quality; 

and Texas Farm Bureau. 

• Local newspaper press releases.

• Door-to-door distribution of flyers about public meetings in 

English and Spanish by APHIS personnel prior to meetings. 

These flyers were also posted in public places near colonias.

How and why is APHIS making the Draft EIS available for public 

comment?

 

In accordance with requirements under APHIS’ NEPA Implementing 

Procedures, APHIS is making this document available to the public for 

4
comment through the Federal Register and also is mailing copies of the 

EIS to members of the public and public agencies who indicated an 

interest in receiving a copy of the document at public meetings and 

through the APHIS website at 

http://www.aphis.usda.gov/animal_health/animal_diseases/tick/. Providing 

public notice of an environmental document to interested or affected 

persons and agencies is consistent with requirements under CEQ and 

APHIS NEPA regulations (40 CFR § 1506.6(b) and 7 CFR §§ 1b, 372, 

respectively). 

C. Background Information Related to the

Proposed Action

What is the proposed action and why is the action being proposed? 

APHIS proposes to provide funding toward the installation of game 

fencing, upon landowner consent and agreement to cost-sharing, in rural 

areas near the Permanent Tick Quarantine Line in Maverick, Starr, Webb, 

and Zapata Counties, Texas, where cattle fever tick (Rhipicephalus 

(Boophilus) annulatus) and southern cattle tick (Rhipicephalus

(Boophilus) microplus) infestations have recurred in recent years. These 

infestations cause lengthy quarantine restrictions on cattle herds and 

increased herd management efforts and expenses to cattle producers in the 

tick-free zone in South Texas. We provide more details about the proposed 

action in chapter 2. 

Why are the ticks a concern?

The cattle fever tick (R. annulatus) and the southern cattle tick 

(R. microplus) (both referred to as “cattle fever ticks”) are agricultural 

pests of concern for U.S. livestock. The cattle fever ticks infest cattle, 

and—occasionally—horses, mules, sheep, goats, or deer. The ticks must 

have blood from an animal host to complete their life cycles. As they feed, 

these ticks spread (are vectors of) protozoan parasites of the genus 

Babesia (blood parasites), the causative agent of babesiosis (also called 

Texas fever, tick fever, redwater, or bovine piroplasmosis). Bovine 

babesiosis is caused by at least two of seven Babesia species that infect 

cattle -- B. bigemina and B. bovis. The ticks acquire Babesia infection 

during their feeding on infected cattle. The infection settles in the ovaries 

of the ticks and thus larvae from infected female ticks carry the infection. 

5
The parasites continue to develop within the larvae, and their transmission 

to the cow or other host usually occurs when the nymph and adult stages 

of the infected ticks feed on the host (Barros and Fighera, 2008). Babesia 

bigemina and B. bovis have been discovered in free-ranging white-tailed 

deer in northeastern Mexico — these deer serve as a reservoir of infection 

that can spread to cattle via cattle fever ticks in South Texas (Cantu-C et 

al., 2009). 

The ticks and their associated diseases, especially bovine babesiosis, or 

cattle fever, pose serious problems to warm-blooded animals. Babesiosis 

is generally characterized by extensive loss of red blood cells due to 

breakdown of the cellular membrane. This leads to anemia, jaundice, and 

death. Infected cattle may exhibit neurological disturbances characterized 

by incoordination, seizures, muscle tremors, hyperexcitability, 

aggressiveness, blindness, head pressing, and coma. In addition, the two 

cattle fever tick species are capable of causing blood loss, significant 

damage to hides, and an overall decrease in the health condition of 

livestock. Less severe cases may be characterized by weight loss and 

secondary bacterial infections. Due to these wide ranging symptoms, 

babesiosis can cause devastating economic losses to owners of affected 

herds (CFSPH, 2008). More details about bovine babesiosis, including 

species affected, geographic distribution, transmission, and clinical signs 

can be found through Iowa State University’s Center for Food Security 

and Public Health at 

http://www.cfsph.iastate.edu/DiseaseInfo/disease.php?name=bovinebabesiosis&lang=en. 

The cattle fever tick life cycle consists of four stages: egg, larva, nymph, 

and adult (figure 1-1). Cattle fever ticks are a one-host tick, meaning that 

they feed on only one host during their life stages (larva, nymph, and 

adult); however, a blood-engorged female tick releases 1,000 to 2,000 

eggs into the surrounding environment after detaching from the host and 

before dying on the ground. This starts the life cycle again, and new hosts 

are sought by the larva after the eggs hatch. Many adult ticks are olive 

green; others are mottled yellow or olive brown in appearance. 

6
Figure 1-1. Cattle fever tick life stages (from left to right; larva, nymph, adult 

engorged female). Photo credit: USDA, APHIS.

Cattle fever ticks spend the early part of their lives on the ground. Newly 

hatched seed ticks, or larvae, are barely visible to the unaided eye. These 

waxy brown, six-legged ticks crawl up grass or shrubs and wait to attach 

to a passing host. The ticks require blood from a host to complete their life 

cycles. If ticks do not find a host, they eventually die of starvation and 

desiccation (extreme dryness). In summer, seed ticks may starve after 3 to 

4 months; in colder periods, they may survive for 6 months before 

starvation. Cattle fever ticks are host-specific and are able to complete 

their life cycles on cattle (their preferred host), horses, donkeys, whitetailed deer, and other animals including axis deer, red deer, elk, nilgai 

antelope, and aoudad (Anderson et al., 2010). 

After a host is found, seed ticks usually first attach themselves to soft skin 

inside the animal’s thigh, flanks, and forelegs or along the belly and 

brisket. There, they suck blood, or engorge. Then these ticks molt twice: 

seed ticks develop into eight-legged nymphs; after engorging about a 

week, nymphs molt to become adults. Tick feeding causes blood loss, and 

they have the potential to transmit Babesia parasites to cattle, which 

subsequently could cause bovine babesiosis. 

In the absence of cattle fever ticks in tick-free areas, the disease bovine 

babesiosis does not occur and the consequence is that cattle do not have a 

natural immunity to the disease. However, cattle that carry Babesia

species and that also bear cattle fever ticks are capable of introducing 

babesiosis into a tick-free area, provided that the timing coincides with 

7
favorable weather conditions from the second generation of ticks (infected 

by transovarian transmission) to transmit the disease to cattle. Likewise, 

other animals that carry Babesia species and that also bear cattle fever 

ticks, such as white-tailed deer and nilgai antelope (Cardenas-Canales et 

al., 2011), are capable of introducing babesiosis into a tick-free area. 

We are concerned about the role of deer, since deer can serve as effective 

cattle fever tick hosts and therefore distribute engorged female ticks within 

their core areas and home ranges (Pound et al., 2010; Anderson et al., 

2010). In one study, home ranges of white-tailed deer, males and females, 

in the western plains of South Texas were measured to be approximately 

264 and 189 hectares (652 and 467 acres; note: 1 square mile = 640 acres), 

respectively (Fulbright and Ortega-S, 2006). Southern cattle ticks have 

been found on hunter-killed white-tailed deer on properties vacated of 

cattle for as long as 10 years (Pound et al., 2010). 

Since bovine babesiosis was eradicated from the United States in 1943, 

there has been no need to vaccinate cattle against the disease. However, 

naïve host cattle that have not been exposed or vaccinated are more 

susceptible to extreme illness if infected.

What is the history of U.S. efforts taken against these ticks? 

The cattle fever ticks were introduced to the New World through livestock 

brought from other countries by colonists and explorers in the early 1500s 

(Anderson et al., 2010). These tick species once occurred in large areas of 

the United States (see figure 1-2) and still occur in a permanent quarantine 

or “buffer” zone (referred to in this document as the Permanent Tick 

Quarantine Zone) of South Texas, in Mexico, and throughout tropical and 

subtropical regions of the Western Hemisphere. 

8
Figure 1-2. Early 1900s range of cattle fever ticks and southern cattle ticks in the 

United States. Credit: Ellenberger and Chapin, 1940.

In the late 1800s, the association between cattle fever ticks and “Texas 

fever” was identified based on research by three scientists (Pound et al., 

2010). In the early 1900s, when large areas of the United States3 were 

affected with the cattle fever tick and the southern cattle tick, the U.S. 

Congress initiated a tick eradication program. Established in 1906, the 

Cattle Fever Tick Eradication Program (CFTEP) was the first cooperative 

State-Federal eradication effort, beginning the sharing of costs and 

cooperation between the Federal Government and 14 southern and 

southeastern States and California (see figure 1-2), local governments 

within each of those States, and individual livestock producers (Houck, 

1921, in Pound et al., 2010). 

From the beginning of the eradication effort, program participants 

developed, tested, and discarded or refined tick eradication techniques, 

eventually narrowing options to two that became commonly used: 

(1) pasture vacation, i.e., the removal of all host livestock from infested 

pastures or premises for a continued period of time that would ensure that 

cattle fever tick larvae would not survive in the absence of hosts and 

(2) systematically treating all cattle, horses, and mules topically with an 

acaricide (pesticide) every 2 weeks until the livestock and premises were 

free of cattle fever ticks (Mohler, 1942, in Pound et al., 2010). Cattle and 

equine (horses, mules, and donkeys) were the focus of the early national 

tick eradication effort. 

3

 The tick-infested area included all or parts of 14 southern and southeastern States, i.e., Texas, 

Oklahoma, Louisiana, Arkansas, Mississippi, Alabama, Tennessee, Kentucky, Missouri, Florida, 

Georgia, South Carolina, North Carolina, Virginia, and a portion of southern California, totaling 

1,813,000 square kilometers (about 700,000 square miles) (Bram et al., 2002).

9

 
In 1938, the focus of the eradication effort in Florida changed to include 

more than cattle when it was determined that white-tailed deer were a 

contributing factor in Florida’s continuing eradication battle in the central 

and southern areas of the State. In 1939, Florida targeted and substantially 

reduced the deer population in the Everglades in a successful effort to stop 

cattle fever tick infestations on wildlife (as reported in “Tick Riders --

Texas-style Border Guards Protect Livestock Health”, September 24, 

1999; available at 

http://www.southernlivestock.com/articles/industry_news/tick_riderstexas

style_border_guards_protect_livestock_health.3783.sls). The effort in 

Florida against the cattle fever ticks also included construction of an 

80-mile, 6-strand, electrified, barbed-wire fence by wildlife managers. The 

purpose for the fence barrier was to restrain tick-infested deer to areas 

south of the fence, thereby preventing spread of the southern cattle tick to 

cattle north of the fence (McAtee, 1939). Cattle also continued to be part 

of Florida’s tick eradication efforts. In 1943, the quarantine was lifted for 

Florida; however, there were several subsequent tick infestations through 

1961. 

In Texas, white-tailed deer had not been a part of the early tick eradication 

program focus. White-tailed deer populations were described to be at an 

all-time low in Texas around 1890 (McDonald et al., 2004). Pound et al., 

2010, discussed that white-tailed deer populations were low or nearly 

extinct in most of the early tick eradication program efforts in 14 of 15 

cattle fever tick-affected States (except for Louisiana and noting the 

unavailable estimates of white-tailed deer population for Florida through 

1935). Over-hunting and the lack of hunting laws and enforcement were 

responsible for the decrease in deer populations in the late 1800s and early 

1900s. It is important to note that hunting laws, such as the designation of 

a deer hunting season, were not established and enforced throughout 

Texas until the late 1950s and early 1960s (Smyrl, 2013). 

The screwworm fly is an obligate parasite of mammals and various 

wildlife species during their larval stage, including white-tailed deer. 

Heavy infestation of screwworms contributed to limited white-tailed 

deer population growth in the early to mid-1900s (Strickland et al., 

1981). Endemic screwworm populations were eradicated from Texas 

and New Mexico in 1964; however, new infestations continued to 

appear in Texas along the Mexican border. An agreement with Mexico 

in 1972 led to a combined effort to eradicate screwworms from Mexico 

and prevent 

10
further incursions into the United States. Screwworms were officially 

eradicated from the United States in 1982, and the majority of northern 

Mexico was considered screwworm-free by 1981 (Novy, 1991). As a 

result, white-tailed deer populations increased due to the absence of the 

screwworm during the 1970s. Therefore, native white-tailed deer were not 

as important through the mid-century as they are today in maintaining and 

spreading cattle fever ticks throughout South Texas because their 

populations remained low through the mid- to late-1900s. 

In 1938, the buffer zone, or Permanent Tick Quarantine Zone, was 

established at the U.S./Mexico border in South Texas where the cattle 

fever ticks continued to be a problem (see figure 1-3 for current regulated 

quarantine zone). In 1943, the two species of cattle fever ticks, R.

annulatus and R. microplus, were eradicated from the United States, with 

the exception of the Permanent Tick Quarantine Zone, which serves as a 

buffer area for conducting surveillance in Texas along the border with 

Mexico. 

Figure 1-3. Map of the current Permanent Tick Quarantine Zone and Permanent 

Tick Quarantine Line (boundary between the quarantine zone and tick-free area) 

within eight Texas counties.

11
After 1943, efforts against the cattle fever ticks were concentrated in 

Texas’ Permanent Tick Quarantine Zone, and annual cattle fever tick 

infestations in the quarantine zone were often traced to movement (stray 

and illegal) of cattle and equine from Mexico. Recurring cattle fever tick 

outbreaks in both the Permanent Tick Quarantine Zone and in the tick-free 

zone were resolved with pasture vacation and systematic treatment of 

cattle with a topical acaricide—two of the tools still used today. Although 

the ticks were eradicated from most of Texas by 1943, vigilant efforts 

against the ticks continued because of the existence of cattle fever ticks in 

Mexico in the border states of Tamaulipas, Nuevo Leon, and Coahuila 

across the Rio Grande and their potential movement via stray or smuggled 

cattle and wildlife, especially deer. 

By 1961, when the last U.S. pocket of the southern cattle tick was 

eliminated from Florida, direct and indirect economic losses caused by 

cattle fever ticks were high—estimated to be $130.5 million, which would 

be approximately $3 billion today (APHIS, 2010). If the ticks had not been 

eradicated from the United States, today’s cattle industry’s losses from 

disease and ticks could amount to approximately $1 billion annually 

(APHIS, 2010). 

In 1965, the Bureau of Animal Industry (APHIS’ predecessor agency) 

approved the use of low-height, double fences for release of premises from 

cattle fever tick quarantine within the Permanent Tick Quarantine Zone 

(figure 1-4). Double-fence placement was primarily located along the 

ridge next to the Rio Grande. The fence was not placed on the river banks 

because sections could be washed away or damaged due to unpredictable 

flooding of the Rio Grande. The double fencing was required to be at least 

15 feet apart and to each have a minimum of 6 barbed wires, with a 

minimum height of 52 inches (slightly higher than 4 feet) and no less than 

12 inches from the ground. The area between the double fences was 

required to be kept free of vegetation (to serve as a buffer for cattle fever 

ticks), and cattle guards were required at entrances of the quarantined 

areas used for operations other than ranching. This requirement focused on 

keeping stray livestock from accessing the premises surrounded by the 

double fences. This effort later proved to be an unsuccessful attempt to 

allow changes to the Permanent Tick Quarantine Line (and Zone), partly 

because of the cost and labor involved in maintaining the fences (owing to 

the fence design and large areas covered) and vegetation removal, but 

mainly because the double fencing did not prevent ungulate (having 

12
hooves) wildlife cattle fever tick hosts from moving ticks beyond lowfenced areas. 

 Figure 1-4. Double fences remain years later after the CFTEP 1965 double 

fence effort (see barbed-wire fence on left and right in photo) to move the 

quarantine zone closer to the Rio Grande. Photo credit: USDA, APHIS.

Approximately 80 miles of double fencing were erected within the 

northern area of the Permanent Tick Quarantine Zone (Val Verde, Kinney, 

Maverick, and Webb Counties) bordering Mexico during the 1960s and 

1970s; however, due to the increased number of tick outbreaks on the 

other side of the fencing, the Permanent Tick Quarantine Line was moved 

back to its original locations in the late 1980s and 1990s. Further 

complicating the control of cattle fever ticks, the Inter-American 

Development Bank funding for cattle fever tick eradication in Mexico was 

discontinued in June 1981, thereby reducing the progress of eliminating 

cattle fever ticks from along the U.S./Mexico border. 

The Permanent Tick Quarantine Zone extends through parts of eight 

counties of Texas parallel with the Rio Grande (the geographical and 

political division between Mexico and the United States). The eight 

counties whose southern boundaries contain a portion of the Permanent 

Tick Quarantine Zone are as follows (from north to south): Val Verde, 

Kinney, Maverick, Webb, Zapata, Starr, Hidalgo, and Cameron (see 

figure 1-3). The distance of the Zone is 583 miles along the Rio Grande 

from Del Rio, Texas, to the Gulf of Mexico, and the width of the Zone 

varies from nearly 125 yards (0.07 miles--an area in Maverick County) to 

8.01 miles wide (an area in Cameron County) from the border with 

13
Mexico. The narrow Zone serves as a buffer between Mexico and the rest 

of the cattle fever tick-free United States, referred to in this document as 

the “tick-free area.” The ticks are well-established in Mexico and continue 

to be a source of infestation in eradicated areas in Texas along the Rio 

Grande. To this day, cattle producers in the Permanent Tick Quarantine 

Zone continue to operate under a special quarantine where vigilant 

surveillance efforts against the cattle fever ticks by State and Federal 

inspectors continue for the protection of U.S. cattle health. 

What has changed? 

White-tailed Deer 

In 1968, cattle fever ticks were discovered on white-tailed deer in ranches 

in Dimmit County and southern cattle ticks were discovered on deer in 

other areas in later years, raising concern about the role of white-tailed 

deer and cattle fever tick outbreaks in the tick-free area. Since then, more 

evidence has been gathered on the role of white-tailed deer as suitable 

cattle fever tick hosts and their importance in tick eradication efforts, 

which has led APHIS to believe that fencing is a worthwhile endeavor to 

control cattle fever ticks. 

Studies have shown that white-tailed deer are suitable hosts for cattle fever 

ticks (Graham et al., 1972, in Pound et al., 2010). In the 1970s, chronic 

cattle fever tick infestations on ranch properties in Webb County north of 

Laredo, Texas, were not resolved by pasture vacation. In 1979, after 

sampling white-tailed deer in an area of Webb County, a study 

demonstrated that white-tailed deer sustained the existence of and spread 

cattle fever ticks within pastures vacated of cattle. This study reinforced 

the conclusion from an earlier study that white-tailed deer can support 

cattle fever ticks within vacated pastures and from another study that 

white-tailed deer distribute the ticks from infested to non-infested 

pastures. 

Success of Fencing

The chronic tick infestations and confirmation of white-tailed deer as a 

source of cattle fever tick sustenance and spread in vacated pastures 

prompted a cattle rancher in Webb County to erect game fencing along 

17.2 miles of property parallel with the Permanent Tick Quarantine Line. 

14
He installed cattle guards at the northern and southern ends of the high 

fence line on access dirt roads. This high fencing effort was successful in 

preventing cattle fever tick reinfestations outside the Permanent Tick 

Quarantine Zone in the tick-free area since its completion in 1984 (see 

figure 1-5). High fencing was later constructed surrounding the entire 

property from the Permanent Tick Quarantine Line to the Rio Grande 

ridge during the mid-1990s. Enclosing this premises with high fencing has 

been successful in drastically reducing tick reinfestations in this area of 

the Permanent Tick Quarantine Zone in Webb County since 1997 (see 

figure 1-5). More importantly, no tick infestations have been discovered in 

the adjacent free area since 1981. 

The following explanations provide additional context to the shaded areas 

in figure 1-5: 

• In 1996, there were two pastures in the Permanent Tick Quarantine 

Zone that were undergoing the mandatory 9-month quarantine 

period during fence construction. 

• In 2009, two pastures were placed under quarantine due to cattle 

fever ticks that most likely were introduced by wildlife from 

Mexico that traversed an opening between premises with high 

fencing. 

Hunter Involvement 

Since the late 1990s, cattle fever ticks continue to be found on hunterkilled white-tailed deer taken on properties that have been cattle-vacated 

for several years (Pound et al., 2010). This suggests that deer can maintain 

a population of cattle fever ticks, even in the absence of cattle. The 

following factors are related to an increased risk of white-tailed deer 

sustaining and spreading cattle fever ticks (Pound et al., 2010): (1) density 

and geographic distribution of deer populations, (2) quality of deer habitat 

and browse abundance, and (3) quality of deer habitat and microhabitat for 

cattle fever tick survival.

15
Figure 1-5. High fencing project in Maverick County showing infested and exposed pastures to cattle fever ticks (gray shaded areas) before 

construction of the high fence along the Permanent Tick Quarantine Line (dotted black line) in 1981, after construction of the high fence (solid 

black line) along the Permanent Tick Quarantine Line in 1984, and after construction of the high fencing surrounding the entire property located in 

the Permanent Tick Quarantine Zone (1996-2009).

 
Cattle Fever Tick Infestations

Figure 1-6 shows the number of cattle fever tick infestations in the 

Permanent Tick Quarantine Zone and the tick-free area from 1959 to 

2011. Between 1978 and 2003, the number of new tick infestations stayed 

below 40 discoveries per year in both the areas. In 2004, a marked 

increase in the number of cattle fever tick infestations occurred (more than 

70 discoveries) in the Permanent Tick Quarantine Zone owing to changes 

in the TAHC regulations that permit premises to be designated as infested 

and quarantined when a cattle fever tick is found on hunter-killed or live 

white-tailed deer. Prior to 2004, premises were quarantined only when 

cattle fever ticks were found on cattle Pound et al., 2010). The finding of 

one cattle fever tick is defined as an outbreak or infestation, based on the 

principle that it takes some level of tick population in existence to make 

the population large enough to find the first one (Anderson et al., 2010). 

Domestic deer are considered livestock by Texas (4 TAC § 

41.1(14)(2002). Also, nonindigenous deer are considered as exotic 

livestock (Texas Agriculture Code § 161.001(a)(4)). Therefore, CFTEP 

personnel may require treatment of deer in vacated premises (Pound et al., 

2010). 

Information in table 1-1 correlates with the graph in figure 1-6 depicting 

cattle fever tick infestations for fiscal years 2001-2011 (a fiscal year is 

based on a time period of October 1 through September 30). 

Table 1-1. Cattle Fever Tick Infestations in the Permanent Tick

Quarantine Zone and Tick-free Area of South Texas

(2001-2011)

Fiscal 

Year

Permanent Tick 

Quarantine Zone

Tick-free Area Annual Total

2001 14 5 19

2002 11 5 16

2003 15 4 19

2004 74 20 94

2005 78 39 117

2006 50 15 65

2007 59 25 84

2008 85 47 132

2009 61 85 146

2010 68 22 90

2011 71 37 108

As indicated in figure 1-6 and table 1-1, in more recent years, cattle fever 

tick infestations, based upon the revised TAHC definition, began to rise 

sharply starting in 2004 in both the Permanent Tick Quarantine Zone and

17
Figure 1-6. Cattle fever tick infestations in Texas by fiscal year, October 1, 1959 – September 30, 2011. Credit: USDA, APHIS.

0

20

40

60

80

100

120

19591960196119621963196419651966196719681969197019711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011

# of new infestations

Free Area Permanent Tick Quarantine Zone
the tick-free area and continue to remain high. The locations of 

infestations from 2004 through 2011 are shown in figures 1-7 through 1-

14. The increase in infestations resulted in large portions of the tick-free 

area being designated as Temporary Preventative Quarantine Areas during 

fiscal years 2007 through 2011 (see figures 1-10 through 

1-14). 

APHIS attributed tick infestations for fiscal years 2004 through 2009 to 

cattle, white-tailed deer, and exotic wildlife, including red deer from 

Mexico (for additional information see wildlife discussion below; Pound 

et al., 2010). APHIS also attributed more infestations to white-tailed deer 

during the October-February period than compared to cattle at the same 

time, further noting that the October-February period coincides with the 

annual deer hunting season and reasoning that deer are inspected by 

hunters and Texas Parks and Wildlife Department personnel more often 

during this time of year (Pound et al., 2010). 

The 2010 report also summarizes the results of the examination of livecaptured deer in cattle-vacated pastures in the counties of Maverick, Starr, 

Webb, and Zapata during 2005 through 2009, indicating that high 

percentages of the deer are infested with cattle fever ticks during other 

times of the year as well. 

In 2009, a Temporary Preventative Blanket Quarantine of more than 

1 million acres in South Texas was established by the TAHC (see figure 

1-12) because of cattle fever tick outbreaks. This represented the largest 

area under CFTEP quarantine in more than 40 years (Anderson et al., 

2010). 

What are the factors related to the control of cattle fever ticks? 

Although there is no specific answer with certainty, numerous factors add 

to the challenges associated with recurring cattle fever tick infestations. 

Wildlife

Native and exotic deer species that serve as hosts for cattle fever ticks are 

abundant in South Texas (Pound et al., 2010). Wild or feral animals such 

as white-tailed deer, red deer, nilgai antelope, and stray livestock (cattle 

and horses included) migrate from Mexico cross the Rio Grande in areas

 19
Figure 1-7. Locations of cattle fever tick infestations during fiscal year 2004 

(October 1, 2003, through September 30, 2004).

Figure 1-8. Locations of cattle fever tick infestations during fiscal year 2005 

(October 1, 2004, through September 30, 2005).

20
Figure 1-9. Locations of cattle fever tick infestations during fiscal year 2006 

(October 1, 2005, through September 30, 2006).

Figure 1-10. Locations of cattle fever tick infestations during fiscal year 2007

(October 1, 2006, through September 30, 2007).

 21
Figure 1-11. Locations of cattle fever tick infestations during fiscal year 2008

(October 1, 2007, through September 30, 2008).

Figure 1-12. Locations of cattle fever tick infestations during fiscal year 2009

(October 1, 2008, through September 30, 2009).

22
Figure 1-13. Locations of cattle fever tick infestations during fiscal year 2010

(October 1, 2009, through September 30, 2010).

Figure 1-14. Locations of cattle fever tick infestations during fiscal year 2011

(October 1, 2010, through September 30, 2011).

 23
where the river is shallow, which provides easy and unimpeded access into 

the Permanent Tick Quarantine Zone. Periods of low rainfall contribute to 

ease of access across the Rio Grande. The animals that cross the Rio 

Grande from Mexico and enter the Permanent Tick Quarantine Zone are 

capable of carrying with them the cattle fever ticks that can harbor B. 

bovis and B. divergens—part of the package for transmitting babesiosis to 

naïve (non-immune) cattle and other animal populations. 

In recent years, surveillance on live white-tailed deer with the use of 

helicopter netting capture-release methods provided information about the 

severity of the tick infestation problem occurring in the white-tailed deer 

population (Duhaime, 2009). Sampling was done within a short timeframe 

(less than 6 hours) of one day. Within the Permanent Tick Quarantine 

Zone, animals from a population of white-tailed deer were captured and 

released on a ranch in Starr County in 2005 and again in 2007. The deer in 

this area were 76 percent infested (19 out of 25 head) with cattle fever 

ticks at the time of the first capture, and 82 percent infested (18 out of 22 

head) at the time of the second capture (Duhaime, 2009; Pound et al., 

2010). On two occasions in the tick-free area of Zapata County in 2008, 1 

(3.3 percent) and 3 (12.5 percent) of sampled deer in a pasture on a ranch 

were infested with cattle fever ticks. Cattle were not stocked on any of the 

pastures where deer were sampled for cattle fever ticks. These findings 

show that deer in the quarantine zone and in tick-free areas carry cattle 

fever ticks and have the potential to transmit them to cattle. 

Climate and Weather

Temperature and humidity have a strong influence on microclimate and 

the subsequent survival of cattle fever tick eggs and larvae (Corson et al., 

2004; Edney, 1982; Teel, 1984). At relative humidity levels of 75 percent 

or more, death of tick larvae is minimal, and the limiting factor for larval 

survival is temperature. When relative humidity is 63 percent or less, the 

survival of larvae is decreased regardless of temperature (Davey et al., 

1991). Therefore, low humidity and long periods of drought can dry out 

cattle fever ticks and greatly decrease vegetation used by ticks on which to 

quest and reach a host. During drought, animals such as white-tailed deer 

that are in search of suitable vegetation for forage or a water source could 

contribute to the spread of cattle fever ticks, especially when congregating 

around food or water sources (Michael, 1968, in Webb et al., 2007). 

24
Suitable tick habitat also can contribute to cattle fever tick reinfestations. 

Bram et al. (2002) report that the progressive conversion of the grassland 

savanna of much of South Texas and adjacent areas of Mexico to brush 

provides a habitat more favorable to the survival of nonparasitic life stages 

of cattle fever ticks. A simulation model evaluated this further and 

assessed how microclimate, habitat heterogeneity (vegetation 

dissimilarities), and within-pasture cattle movement may influence cattle 

fever ticks in South Texas. The sensitivity analysis of the model showed 

that temperatures and relative humidities created by habitat type (grass 

versus shrubs) and engorged female tick mass influenced tick population 

dynamics most strongly, as well as host habitat selection, initial number of 

larvae per cow, and the number of cells into which the simulated pasture 

was divided (Corson et al., 2004). 

Cattle Fever Ticks and Acaricide Resistance 

Certain strains of cattle fever ticks have demonstrated increased resistance 

to the topical use of the chemical formulations used to kill them. 

Acaricide resistance can occur when an acaricide, such as coumaphos, is 

not properly used. This occurs, for example, if too low of a dose to 

achieve lethal toxicity is used or the continued frequency of treatments 

contributes to selection for resistant ticks in a geographical region (Miller 

et al., 2005). We have known about resistance to coumaphos in southern 

cattle ticks (R. microplus) in Mexico since the 1980s (Miller et al., 2005). 

Eight strains of southern cattle ticks from the northern areas of Mexico’s 

States of Tamaulipas, Nuevo Leon, and Coahuila and two strains of cattle 

fever ticks from infestations in the Permanent Tick Quarantine Zone in 

South Texas have varied levels of resistance to the organophosphate class 

of acaricides specifically (amitraz, coumaphos, and diazinon)—used in 

Mexico for controlling cattle fever ticks (Li et al., 2003; Li et al., 2004). 

While organophosphate acaricides, specifically coumaphos and diazinon, 

played an important role in Mexico’s control of the southern cattle tick 

during 1975 to 1985, tick resistance to these acaricides is the consequence 

of their extensive use in Mexico’s efforts for tick control (Li et al., 2003). 

Tick resistance to the same acaricides used in South Texas as in 

northeastern Mexican states presents another challenge to the success of 

the CFTEP. Miller et al. (2005) report that an investigation of southern 

cattle ticks (R. microplus) collected in August 2004 from cattle in the 

 25
Permanent Tick Quarantine Zone of Starr County, Texas, found that some 

ticks from the collection were resistant to coumaphos. This leads to 

concerns about resistant tick populations becoming established in the 

United States. 

Funding 

The National Tick Eradication Program in Mexico began with a 

MEX$35,000,000 (pesos) loan from the Inter-American Development 

Bank in 1975. This amount represented 19.3 percent of the total cost for 

the Program, which was estimated at MEX$178,000,000 over a 5-year 

period. Federal, State, and local governments provided funding, including 

special taxes on the sale of cattle throughout Mexico. Credit from the 

initial Inter-American Development Bank investment ended during June 

1981. The Development Bank approved a second line of credit for an 

additional MEX$90,000,000; however, the Mexican government decided 

not to accept the new loan based on changing economic and financial 

situations in Mexico. As a result, progress gained in eradicating cattle 

fever tick populations from northern areas in Mexico was halted, and 

cattle fever tick populations began to reestablish in these previously 

eradicated locations.

Mexico is faced with cattle fever tick challenges in wildlife and livestock. 

The Secretaría de Agricultura, Ganadería, Desarollo Rural, Pesca Y 

Alimentación (SAGARPA, or Ministry of Agriculture, Livestock, Rural 

Development, Fishing, and Food), the agency responsible for livestock 

health in Mexico, has been operating under a reduced budget for some of 

its animal health programs, including cattle fever tick control in the 

northern areas of Mexico near the U.S. border. Mexican border state 

governments have also experienced reduced budgets for cattle fever tick 

control in recent years. 

Cost of Cattle Fever Tick Spread

If not contained, re-emerging cattle fever ticks in South Texas could 

spread into U.S. tick-free zones of the cattle fever tick historical range in 

15 States, which would be devastating to U.S. cattle production in those 

areas and to U.S. cattle health and food supply. According to an economic 

impact report prepared in 2010 by the Agricultural and Food Policy Center 

at Texas A&M University, the cost for the first year of a tick eradication 

26
effort for a small outbreak, starting with three infestations in the tick-free 

zone of Texas, is estimated to be $123 million, with subsequent annual 

costs of about $97 million per year (Anderson et al., 2010). These 

estimates are conservative and are based on assumptions and unknown 

factors, and they do not include costs for ongoing eradication activities in 

the Permanent Tick Quarantine Zone. A year-one minimum cost for an 

extended cattle fever tick outbreak in the historic range of the ticks would 

be $1.2 billion, plus the cost of developing infrastructure for inspection 

and surveillance for ticks in those areas (Anderson et al., 2010). 

II. Purpose and Need for the

Proposed Action

The purpose for providing funding toward the installation of game fencing 

is to assist cattle producers and the CFTEP Mounted Patrol Inspectors in 

limiting the movement and dissemination of cattle fever ticks by host 

wildlife, to the degree possible, in areas where recurring cattle fever tick 

infestations have been detected in recent years. 

Recurring cattle fever tick infestations result in increased quarantine 

efforts in areas beyond the Permanent Tick Quarantine Line in South 

Texas. When quarantine efforts are increased as a result of cattle fever tick 

infestations, cattle producers are burdened with cattle movement 

restrictions and higher production costs associated with eradicating these 

ticks. Increased quarantine efforts add increased workload (see 

figures 1-15 and 1-16) and costs for the CFTEP Mounted Patrol Inspectors 

and TAHC employees responsible for protecting animal health. CFTEP 

efforts related to tick infestations beyond the Permanent Tick Quarantine 

Line from fiscal year 2007 through 2011 in one location of the tick-free 

area (the Carrizo Springs area of Dimmitt County) cost APHIS nearly 

$10 million. 

Based on a low estimate of approximately $22,000 per mile of game 

fencing, we estimate that a one-time APHIS cost-share of 50 percent for 

installation of game fencing with landowners in all the areas of need 

(discussed in chapter 2 under the Proposed Action section) would cost less 

than 1/10th of the amount of CFTEP efforts during fiscal years 2007-2011 

combined for Dimmit and Maverick Counties. Based on the costs 

 27
associated with CFTEP efforts during recent years, the installation of 

game fencing is a cost-effective tool to reduce the spread and recurrence 

of cattle fever ticks in problematic areas, allowing the CFTEP Mounted 

Patrol Inspectors to focus efforts within the Permanent Tick Quarantine 

Zone—the area of first defense.

No tool alone is 100 percent effective against cattle fever ticks. The 

cooperative Federal, State, local, and private initiative will continue 

vigilant surveillance and inspection for tick-infested cattle and wildlife, 

acaricide dip or spray treatment of livestock (primarily cattle and horses), 

and pasture vacation to help protect cattle from potential exposure to the 

pathogen that can be transmitted by the cattle fever ticks. Game fencing 

would provide an additional tool to help prevent the unimpeded movement 

of cattle fever tick spread by white-tailed deer and other ungulates from 

Mexico, thereby reducing or preventing tick outbreaks in the tick-free 

zone. 

The use of game fences is not a new concept. Fences are used in many 

situations throughout the world as a method for preventing disease 

transmission from wildlife to other wildlife, livestock, and humans; crop 

loss or damage; automobile and aviation collisions; habitat destruction and 

environmental damage; and more (Taylor and Martin, 1987; VerCauteren 

et al., 2006). Game fencing installed along approximately 17 miles of 

property parallel with the Permanent Tick Quarantine Line for the purpose 

of preventing cattle fever tick reinfestations and potential transmission of 

babesiosis from white-tailed deer to cattle has proven to be successful for 

more than 27 years. Electrified, 6-strand, barbed-wire fencing was 

successfully used in Florida in the 1930s to help eliminate the spread of 

cattle fever ticks by white-tailed deer (McAtee, 1939; VerCauteren et al., 

2006). 

The proposed fencing is needed to prevent the potential spread of cattle 

fever ticks northward and to reduce exposure risk of cattle and other 

susceptible animals to babesiosis in the U.S. tick-free zone. The cattle 

fever ticks can survive in the southern half of the United States, where 

they were once established and subsequently eradicated during the 1900s 

(Pound et al., 2010). U.S. cattle populations are naïve to babesiosis, a 

debilitating and fatal disease. Additionally, game fencing also would 

reduce the need for additional uses of acaricide to treat cattle and horses 

when Temporary Preventative Blanket Quarantines (large areas containing 

28
infested, adjacent, exposed, vacated, and checked premises) result from 

the spread of cattle fever ticks. 

Without the fence, unimpeded wildlife movement north of the Permanent 

Tick Quarantine Line would require increased operational effort and 

funding and also presents a threat to the Nation’s livestock health and food 

supply. Funding for fencing, therefore, would help sustain U.S. cattle 

production, sustain cattle export trade, and prevent economic hardship to 

U.S. cattle producers. 

 29
Figure 1-15. CFTEP annual number of cattle inspected in both Permanent Tick 

Quarantine Zone and Tick-free Area, 1993-2011. Credit: USDA, APHIS.

Figure 1-16. CFTEP annual number of cattle inspected in Permanent Tick 

Quarantine Zone (Systematic) and Tick-free Areas, 1993-2011. Credit: USDA,

APHIS. 

0

10

20

30

40

50

60

70

80

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

500000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Percent Treated Annually

Total # Livestock Inspected

Livestock Inspected Percent Treated Animals

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

500000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Total # Livestock Inspected Cattle Inspections (Systematic) Cattle Inspections (Free Area)

30
II. Alternatives

The CEQ’s NEPA regulations (40 CFR §§ 1500-1508) require Federal 

agencies to consider in their environmental documents other reasonable 

courses of actions (alternatives) to any proposed action. In addition to the 

proposed action, a “no action” alternative is always an alternative to 

consider, representing the baseline or the current situation in the absence 

of the proposed action. 

This EIS considers two possible alternatives for further analysis: (1) No 

Action—APHIS will provide no funding assistance toward installation of

game fencing, and (2) the Proposed Action—APHIS will provide funding 

assistance toward installation of game fencing in identified areas of need 

along the Permanent Tick Quarantine Line. These alternatives are 

discussed in this chapter and are the basis for further analyzing potential 

environmental effects addressed in chapter 4 of this EIS. 

Prior to initiating this EIS, APHIS considered other options to the game 

fencing. APHIS also solicited for and received additional alternatives 

during the public scoping period for the EIS. During the public scoping 

period, it was suggested that APHIS include an additional location for 

game fencing where recurring tick infestations were problematic in recent 

years. After further consideration, APHIS modified the proposed action to 

include the additional location, which is consistent with the purpose of and 

need for the proposed action. APHIS dismissed other alternatives from 

further consideration if they did not specifically meet the purpose of and 

need for the proposed action. The dismissed alternatives are discussed 

later in this chapter. 

A. No Action: Continue to conduct current program 

operations without installing game fencing 

Under the No Action Alternative, APHIS would not provide any funding 

toward the installation of game fencing in rural locations where recurring 

cattle fever tick infestations are problematic in Maverick, Starr, Webb, and 

Zapata Counties, Texas to prevent the spread of cattle fever ticks from 

tick-infested areas of Mexico by host wildlife ungulates. 

1. Livestock 

Program 

Activities in 

the 

Permanent 

Tick 

Quarantine 

Zone

31
APHIS would continue to carry out current program operations that help 

prevent the spread of ticks and potential exposure of cattle to babesiosis 

without the aid of game fencing, cost-shared by APHIS, in areas of need. 

Program activities carried out to help prevent the introduction and spread 

of cattle fever ticks in the Permanent Tick Quarantine Zone would

continue, including inspection of livestock at selected South Texas 

markets handling livestock originating from the Permanent Tick 

Quarantine Zone, patrols for stray or smuggled livestock in the Permanent 

Tick Quarantine Zone along the Rio Grande, and inspection and pesticide 

treatment of tick-host livestock (mostly cattle and horses) on quarantined 

premises. 

APHIS cattle fever tick regulations (9 CFR § 72) provide requirements for 

inspection, interstate movement, and permitted dips and procedures for 

cattle in quarantined areas or where tick eradication is conducted in 

cooperation with State authorities. APHIS regulations (§ 72.5) incorporate 

by reference the quarantined areas (4 TAC §§ 41.14-41.22) as described 

by TAHC. 

The Permanent Tick Quarantine Zone, also known as the permanent buffer 

zone or systematic area, is located in South Texas between the Rio Grande 

and the officially designated Permanent Tick Quarantine Line (§§ 41.14-

41.22). The Permanent Tick Quarantine Zone (§ 41.4) is treated as a 

permanently designated surveillance area for tick-infested stray and 

smuggled livestock from Mexico. The Permanent Tick Quarantine Zone 

encompasses 545,348.4 acres within eight counties, stretching 583.7 miles 

from the Gulf of Mexico to the Amistad Reservoir north of Del Rio. The 

Permanent Tick Quarantine Line runs along existing roads, such as 

U.S. Highway 83, U.S. Highway 277, and portions of the El Indio 

Highway 1021 (also called Mines Road). The distance between the border 

of Mexico (Rio Grande) and the Permanent Tick Quarantine Zone varies 

from 0.07 miles in an area of Maverick County to 8.01 miles in an area of 

Cameron County. 

Approximately 60 inspectors, known as CFTEP Mounted Patrol 

Inspectors, carry out surveillance in the Permanent Tick Quarantine Zone. 

Monitoring for stray and smuggled livestock occurs along a trail parallel 

with the Rio Grande and throughout all contiguous country along the 

Permanent Tick Quarantine Line. When inspectors find stray livestock 

from Mexico, they restrain their movement, hand-scratch inspect

32
(manually feel the skin of the animal from head to hoof for ticks), treat 

them on-site with a hand-held sprayer, and then take them to an APHISowned holding pen. From this stage, they are processed and claimed by 

their owners in Mexico or sold at auction for movement only to slaughter 

if not claimed. 

Within the Permanent Tick Quarantine Zone, inspectors also visually 

examine premises containing livestock every 7 to 14 days and inspect and 

conduct acaricide treatment of any stock that owners want to move from 

the Permanent Tick Quarantine Zone. 

When a tick is found on a livestock owner’s premises, either in the 

Permanent Tick Quarantine Zone or beyond the Zone in the tick-free area, 

two options are available to the owner: (1) leave the livestock in the 

pasture and treat the livestock with an approved acaricide (coumaphos) 

every 7 to 14 days for a 6- or 9-month period depending upon the time of 

year the cattle fever ticks are found—this is called systematic treatment—

or (2) vacate the pasture for the same period of time 6 Texas Agriculture 

Code § 167). For tick eradication purposes, the intent of vacating the 

pasture is to prevent tick larvae from accessing hosts for a long enough 

period of time to eliminate sustainable tick populations. The larval-toadult feeding phase on a host requires 18 to 20 days to complete, after 

which the adult females detach and lay eggs. The emergence of new larvae 

can span 1 to 9 months, depending upon temperature, precipitation, 

available vegetation cover, oviposition (the process of laying eggs), and 

incubation (TAMU, 2011). 

Before vacating the pasture, livestock must be scratch-inspected and 

receive two clean treatments at a 7- to14-day interval before being allowed 

to move from the infested premises (4 TAC § 41.6). Movement of the 

livestock is allowed by the TAHC’s issuance of a permit (§ 41.5). 

Other procedures conducted in coordination with these two options—

whether in the Permanent Tick Quarantine Zone or a Temporary 

Preventative Quarantine Area—during the entire length of the quarantine 

include: 

• Examination of infested pastures by a qualified animal health 

technician or tick inspector at least once every 14 days. 

33
• Fence checks to ensure that livestock from other pastures are not 

intermingling in infested pastures.

• Marking cattle with paint at time of treatment and checking the 

entire herd for marking to ensure all cattle are treated with 

acaricide during their systematic treatment timeframe.

• Examination of vacated pastures to ensure that no livestock 

(generally cattle, but also could include horses, sheep, or goats) 

were left behind and that no new livestock has entered the vacated 

pasture due to a break in a fence. 

• Treating ranch horses on quarantined premises for cattle fever ticks 

every 7 to 14 days with coumaphos administered by a hand-held 

sprayer. The horses used by CFTEP Mounted Patrol Inspectors

also are sprayed with coumaphos (Texas Agriculture Code § 167). 

When cattle fever ticks are confirmed on livestock that is on a premise for 

more than 14 days without systematic treatment, the premises is 

considered to be an “infested premise” (4 TAC § 41.1(13)). The TAHC

places all premises bordering infested premises, whether separated by a 

fence or having the same owner as the adjacent premises into the 

Temporary Preventative Quarantine Area. The Temporary Preventative 

Quarantine Area is designated by TAHC for systematic inspection and 

treatment of livestock and premises, and control of movement of livestock, 

in order to detect and eradicate infestation and exposure from infested or 

exposed premises outside the tick eradication quarantine area. The extent 

of the area is determined by evaluating the barriers to the potential spread 

of ticks (§§ 41.14-41.22).

Requirements for the adjacent premises (§ 41.1(1)) are as follows:

• The quarantine period for adjacent premises lasts for the same 

period of time as the infested premises (adjacent premises are 

released from quarantine when the infested premises is released).

• CFTEP Mounted Patrol Inspectors on horseback conduct visual 

inspections on all range cattle every 14 days. 

• A CFTEP representative examines fences every 14 days.

• Livestock are permitted to move from the premises after one dip 

treatment followed by a hand-scratch inspection. The TAHC issues 

the permit allowing movement of the livestock (6 Texas 

Agriculture Code § 167). 

34
Occasionally, APHIS and TAHC inspectors find cattle fever ticks attached 

to the hides of deer killed by hunters. Hunters that kill deer on infested and 

adjacent premises must be inspected, treated, and permitted prior to 

removal from the property. Hunters that kill deer on other properties 

within the temporary quarantine areas must either leave the hide behind, 

freeze the hide for one day, or have the hide inspected prior to removal 

from the property (TAHC, 2010). 

There are few options available to eradicate cattle fever ticks from deer. 

Medicated corn treatment is one such option that is sometimes used in 

South Texas and involves the strategic placement of deer feeders 

containing corn treated with the acaricide, ivermectin. Medicated corn is 

not used during the hunting season, and per use restrictions, its use is 

discontinued at least 60 days prior to the beginning of the hunting season. 

APHIS is investigating the use of a passive treatment method involving 

the use of roller device technology developed by USDA’s Agricultural 

Research Service. The rollers are attached to deer feeders and are 

“charged” with an oily formulation of permethrin, and deer rub on these 

rollers while feeding on corn. Once the treatment contacts their necks, the 

deer distribute the treatment to other parts of their bodies during regular 

grooming. The permethrin treatment is capable of killing and repelling 

cattle fever ticks; however, the passive treatment method is still being 

evaluated to determine its usefulness in eradicating cattle fever ticks from 

infested premises. 

Climatic trends in South Texas are expected to increase deer migration 

and foraging as they look for available food and water sources. According 

to the U.S. Global Climate Change Research Program (Karl et al., 2009), 

average temperatures in the Southern Great Plains (Texas) increased 

across the region, and are projected to continue this increase. Cold days 

are becoming less frequent and hot days are more frequent. Precipitation is 

projected to decrease, causing the southern Great Plains to become drier. 

In 2011, Texas experienced the most intense one-year drought since 

statewide weather records were initially maintained in 1895 (NielsenGammon, 2011). These climatic trends are expected to shift the ranges of 

native plants as they become less competitive in areas where they are not 

well adapted. Weather events affecting soil erosion also are associated 

with shifts in host plant density, and may alter the ease and frequency of 

deer migration. Therefore, as the area becomes hotter and drier, and water 

2. Treatment 

of Whitetailed Deer 

and Exotic 

Ungulates 

on 

Infested 

Premises

35
as well as food preferred by deer becomes scarce, we anticipate that whitetailed deer will migrate — and potentially spread ticks — over greater 

areas.

When cattle are imported from areas of Mexico where there are cattle 

fever ticks, APHIS inspects them (visual and hand-scratch inspection of 

individual animals) at their U.S. port of entry before entering the United 

States and dipped in vats containing coumaphos to prevent the potential 

introduction and spread of the ticks. If ticks are found, then the entire lot 

of Mexican cattle is quarantined, treated, inspected, and then treated again 

approximately 7 to 14 days later. If ticks are not found after the second 

dipping/inspection, then they are allowed to enter the United States (4 

TAC § 41.12; 6 Texas Agriculture Code § 167). 

B. Proposed Action: Provide funding assistance to 

install game fencing in areas of need 

Under this alternative, APHIS would contribute partial funding (in 

accordance with terms of funding provided to APHIS)4 toward installation 

of game fencing on privately owned property in rural locations, upon 

landowner agreement, where recurring cattle fever tick infestations are

problematic in Maverick, Starr, Webb, and Zapata Counties, Texas. 

APHIS would provide flexibility in determining the most logical 

placement of game fencing on a landowner’s property, depending upon 

the particular situation. APHIS would not contribute funding toward game 

fencing that would be located in wetlands or that would obstruct arroyos 

or streams; an APHIS agreement providing funds to a landowner would 

include concurrence with these stipulations. 

Game fencing would serve as an additional tool in needed areas to help 

CFTEP personnel prevent cattle fever tick reinfestations beyond the 

Permanent Tick Quarantine Zone. The CFTEP surveillance and 

eradication activities described above in section A would continue. 

APHIS will partially fund game fencing a minimum of 8-feet high on 

private land in rural areas near the Permanent Tick Quarantine Line where 

recurring tick infestations have occurred in recent years. It would be 

4

 APHIS will determine the amount of funding and the cost-share at a later date and through a 

premises-by-premises evaluation. Some premises may qualify for additional funding from other 

sources such as the Texas Department of Agriculture, Texas Farm Bureau, and USDA’s Natural 

Resources Conservation Service (NRCS). 

3. Treatment 

of Imported 

Cattle from 

Mexico

1. General 

Location of 

Game 

Fencing

36

 
installed in areas of need to prevent access of cattle fever tick host wildlife 

from spreading ticks to the tick-free area. The properties where the game 

fencing is proposed are privately owned lands in rural locations and are 

primarily used for cattle ranching. Game fencing would not obstruct 

public or private access roads or driveways or be installed through 

township areas or across water resources, including streams and arroyos. 

To maximize the cost/benefit ratio, in areas of need where some 8-foot 

game fencing exists near and parallel with the Permanent Tick Quarantine 

Line, the additional proposed game fencing would connect with the 

existing fencing. In some areas where a standard 4-foot fence exists and 

game fencing is proposed, the lower fence could be modified by extending 

the height of the fence, if feasible. 

The estimated measurement of locations where there is a need for game 

fencing is 5.25 miles for Maverick County, 12.46 miles for Starr County, 

7.8 miles for Webb County, and 45.82 miles for Zapata County, for a total 

of approximately 71 miles overall (Appendix H). The total amount of 

game fencing installed would depend upon landowners’ consent for game 

fencing on their properties and cost-share agreements with APHIS. The 

targeted areas in the northern rural areas (Maverick and Webb Counties) 

of the Permanent Tick Quarantine Zone are comprised of large land 

parcels; in the southern rural areas (Zapata and Starr Counties), the 

targeted areas are smaller land parcels comprising many individually 

owned properties. After the landowner agrees to install game fencing and 

to share the cost, APHIS and the landowner would enter into a contract 

that would include stipulations to assist APHIS’ compliance with 

environmental laws and other requirements. This would include an 

agreement to incorporate mitigation measures established by APHIS to 

minimize adverse impacts to the environment. 

In Maverick County, we propose placing game fencing parallel to the 

Permanent Tick Quarantine Line on the south side of Mines Road. In 

Webb County, we propose placing game fencing parallel to the Permanent 

Tick Quarantine Line on the south side of U.S. Highway 83. And in 

Zapata and Starr Counties, we propose placing game fencing on the south 

side of U.S. Highway 83. In these cases, U.S. Highway 83 would provide 

a buffer for ticks dropped on the south side of the Permanent Tick 

Quarantine Line. However, in some situations, a landowner with cattle on 

the north side of U.S. Highway 83 may benefit more from the installation 

of game fencing on the north side of U.S. Highway 83 along [parallel to] 

37
the TAHC quarantine line than on the south side of the highway. This is 

especially true if existing game fencing surrounds the property except for 

the highway frontage that is low-fenced. In these cases, we would work 

with the landowner on the ideal placement of the fencing. 

In some situations, a landowner may own property on both the north side 

and south side of U.S. Highway 83, and it may be beneficial to install 

game fencing on the south side of the highway closer to the Rio Grande. A 

landowner also may have existing game fencing along the Permanent Tick 

Quarantine Line but could benefit from fencing in another property 

location to close a gap in existing fencing and prevent access to cattle 

fever tick hosts. 

Although the majority of game fencing is proposed for contiguous 

placement parallel with the Permanent Tick Quarantine Line, placement 

would be determined based upon consideration of factors that meet the 

purpose and need for the game fencing. Additionally, placement of 

fencing may be modified, depending upon the need to mitigate potential 

environmental effects and depending upon factors such as existing game 

or high fencing on or adjacent to the property, land management uses of 

the property, and management needs for preventing additional cattle fever 

tick infestations. 

Other considerations for the Proposed Action include climate and 

greenhouse gas emissions. Climatic trends are expected to shift the ranges 

of native plants northward and could increase animal migration and 

foraging for scarce water resources. Greenhouse gas emissions that should 

be considered and are associated with this alternative arise from the 

production of fencing materials, fencing installation (including travel 

to/from construction sites), and subsequent travel associated with fence 

maintenance. Total emissions are anticipated to be less than 25,000 metric 

tons annually. 

Fencing locations where APHIS has determined a need for game fencing 

to prevent cattle fever tick infestations in the tick-free zone are described 

below. 

a. Maverick County

• Northernmost short stretch of game fence along Mines Road (north 

of El Indio). Start 28°38'42.19" N, 100°25'2.16" W; Stop 

2. Specific 

Placement 

of Game 

Fencing

38
28°37'41.76" N, 100°23'57.25" W. The fence would be located on 

the south (river side) of Mines Road. The length of the game 

fencing segment is approximately 1.57 miles. Refer to Appendix H 

(Map A) for a close-up view of this proposed game fencing 

segment. 

• Just north of town center El Indio. Start 28°31'26.39" N, 

100°18'44.92" W; Stop 28°30'28.08" N, 100°18''13.09" W. The 

fence would be located on the north side of Mines Road. The 

length of the game fencing segment is approximately 1.0 mile. 

Refer to Appendix H (Map B) for a close-up view of this proposed 

game fencing segment. 

• Start 28°12'14.92" N, 100°9'57.7" W; Stop 28°12'1.59" N, 

100°7'36.6" W. The fence would be located on the north side of 

Mines Road. The length of the game fencing segment is 

approximately 2.4 miles. Refer to Appendix H (Map C) for a 

close-up view of this proposed game fencing segment. 

b. Webb County

• North end of fence on FM 1472 (Mines Road) 27°53'19.04" N, 

99°50'20.16" W, south end 27°46'43.39" N, 99°47'42.77" W. The 

fence would be located on the south side of U.S. Highway 83. The 

length of the game fencing segment is approximately 7.8 miles. 

Refer to Appendix H (Map D) for a close-up view of this proposed 

game fencing segment. 

c. Zapata and Starr Counties

South of Webb County, approximately 56.44 miles of game fence is 

proposed to be installed in place of existing highway right-of-way fence 

on the south side of U.S. Interstate 83. The fence would start just south of 

the Webb County/Zapata County line at mile marker 752 in rural locations 

only and skipping roads and water resources and extending to Roma, 

Texas, ending north of Roma High School in Starr County, to mile marker 

766. One, two-mile portion of the proposed fencing between the towns of 

San Ygnacio and Zapata would be installed on the north side of U.S. 

Interstate 83 between the southwest corner of the high-fenced Las Avispas 

pasture (approximately 9.57 miles southeast of San Ygnacio) and the 

northwest corner of the high-fenced Alexander pasture (approximately 

39
3.17 miles northwest of Zapata). Refer to Appendix H (Map E to K) for a 

zoomed-in map view of these proposed game fencing segments. 

The game fence would be a minimum height of 8 feet and made using 

high-carbon galvanized steel ends, braces, angles, line posts (T-posts), and 

clips and 2 3/8-inch line pipe (figure 2-1). The fixed-knot fencing would 

be made with a minimum of 12.5-gauge net wiring (17/96), class 3 

(galvanized) material. To prevent rusting, line and brace posts would 

include a rust-inhibited coating, primer, and green paint. A single H-brace 

would be installed approximately every 1⁄4-mile as stretch braces and 

would be set approximately 2 1/2 feet deep in concrete. Excavated soil 

would be scattered around each post. Earthen diversion berms may be 

required in some locations to prevent erosion beneath the fence. T-posts 

would be spaced at a maximum of 20-feet apart. 

Figure 2-1. Example of wire-knot game fencing. Photo credit: USDA, APHIS.

 

The wire-knot design of the game fence also could include ladders for 

human access as well as gates for vehicle access (including farm 

equipment). These accesses would be up to the discretion of the property 

owner. The fencing design also may include other special needs in some 

locations to prevent animals from being injured or to allow small wildlife 

species to pass through. Under ideal conditions and with a straight run, 

approximately 1 mile of fence could be installed in one week. 

3. Details of 

Game 

Fence 

Installation

40
If necessary, staging sites (locations for fencing material delivery and 

work equipment) would be provided on privately owned properties of 

landowners who agree to the installation of game fencing and in areas that 

would not be greatly impacted by the work activities for fence installation. 

To comply with environmental laws and other environmental review 

considerations, staging sites would occur in previously cleared areas, 

roads, or driveways and would not impact federally listed threatened or 

endangered species or migratory birds. The sites would be determined on a 

case-by-case basis, depending upon the location of the fencing and an 

agreement between APHIS and the concurring landowner. 

At the discretion of a landowner, if an existing lower fence is present in 

the area where game fencing is agreed to be installed, the game fencing 

either could replace an existing low or four-wire fence, or it could be 

constructed by adding to the existing low fence if it could support a higher 

fence extension (figure 2-2).

Figure 2-2. Low fence with a high game fencing extension. Photo credit: 

USDA, APHIS.

41
A crawler tractor, a type of equipment that is generally used to prepare 

ground for fence installation, would be used where needed to prepare the 

surface of the ground by removing vegetation and leveling. An area at 

least 20-feet wide may need to be cleared of vegetation and leveled in 

preparation for installing the fence. Based upon an area of 20-feet wide, 

each mile of prepared area is equivalent to a total 3.03 acres. Some areas 

could require less preparation than other areas because they already have 

existing low fences that are maintained and free of growth, thereby 

requiring little removal of vegetation. Vegetation removal is maintained in 

many of these types of areas because the existing fences are along 

property access clearings used by property owners or managers, or the 

clearings are adjacent to maintained rights-of-way. 

According to the Commodity Credit Corporation’s terms of funding set 

aside for the game fencing, landowners would be responsible for 

maintaining and repairing the fencing and for removing vegetation. 

CFTEP Mounted Patrol Inspectors conducting daily surveillance along the

Permanent Tick Quarantine Line would notify landowners of needed 

repairs to the fencing. The landowner would also be responsible for 

periodically removing or mowing vegetation. This may occur once or 

twice per year. 

C. Other Alternatives Considered but Dismissed

Prior to the EIS scoping process, APHIS considered other alternatives to 

the Proposed Action discussed above and determined that some of the 

alternatives did not warrant further consideration because they were 

contrary to the purpose and need for the Proposed Action. During the EIS 

scoping process, which included electronically submitted comments and 

comments made at public meetings, APHIS heard other suggested 

alternatives to the APHIS Proposed Action as it was described at that time. 

Suggested alternatives to the Proposed Action ranged from not installing 

game fencing (which is the No Action alternative) to where fencing should 

and should not be located. 

At the time of the public scoping meetings, APHIS initially considered 

providing funding toward the installation of game fencing in rural areas of 

Maverick, Starr, and Zapata Counties along Mines Road and U.S. 

Highway 83, parallel to the TAHC eradication line in a contiguous 

4. Maintenance

of Game 

Fencing

42
manner. The initially proposed alternative and other alternatives 

mentioned during the meeting are discussed further in this section. 

Prior to the EIS public scoping meetings, APHIS was considering an 

alternative, similar to the Proposed Action described above, except that the 

game fencing would be contiguously located on privately owned land in 

rural areas on both the north and south sides (depending upon the location 

of existing game fencing) of Mines Road in Maverick County and on the 

south side of U.S. Highway 83 in Zapata and Starr Counties, parallel with 

the TAHC Permanent Tick Quarantine Line. Game fencing would not 

block driveways, roads, or other access ways and would not be located in 

sensitive areas, such as wetlands. APHIS would provide funding toward 

the installation of game fencing in rural areas where recurring cattle fever 

tick infestations have been problematic in the tick-free zone north of the 

Permanent Tick Quarantine Line in rural areas of Maverick, Starr, and 

Zapata Counties. 

Considering that the concern for movement of cattle fever ticks is north of 

the Permanent Tick Quarantine Line, the highway would provide a buffer 

between land on the north side (tick-free zone) and south side (permanent 

quarantine zone) of U.S. Highway 83 in Zapata and Starr Counties. In 

Maverick County, Mines Road would provide a buffer between the land 

on the north and south sides of the road. This initial proposal at the time of 

the EIS public scoping meetings did not include a segment of Webb 

County that experienced recurring tick infestations during the 2006 to 

2011 Temporary Preventative Quarantines. 

During the public scoping meetings, attendees offered suggestions for 

placing game fencing in areas other than the contiguous locations 

proposed. Suggestions for different locations were based upon specific 

landowner needs involving contiguous placement on landowner property 

parallel with U.S. Highway 83. This included the addition of a segment in 

Webb County on the south side of U.S. Highway 83 where tick 

infestations occurred in recent years. In some situations, placement of the 

fencing other than parallel and close to U.S. Highway 83 would better 

meet the purpose of and need for the Proposed Action because of a 

landowner’s specific situation. The current Proposed Action discussed 

above originated from this alternative but was modified to consider caseby-case circumstances where game fencing may be more suitable in a 

1. Provide 

funding for 

game 

fencing in 

contiguous 

placement 

along the 

TAHC 

Quarantine 

Line

43
slightly different location within the Permanent Tick Quarantine Zone and 

to extend the game fencing to an area of need in Webb County. 

Game fencing along the entire 500 miles of the Permanent Tick 

Quarantine Line would not be consistent with the purpose of and need for 

the Proposed Action. The intent for the use of game fencing proposed in 

the areas of need is to reduce the likelihood that cattle fever ticks will 

spread outside of the Permanent Tick Quarantine Zone, which would 

reduce the number of Temporary Preventative Quarantine Areas. This in 

turn could allow for increased surveillance by CFTEP Mounted Patrol 

Inspectors along unfenced areas of the Permanent Tick Quarantine Line. 

We requested and have funding for areas that had recurring tick 

infestations that resulted in temporary blanket quarantines from 2006 to 

2011 (the areas noted in figures 1-9 to 1-14 in chapter 1). Funding is 

limited and was provided to cover a cost-share for approximately

100 miles of game fencing for cattle fever tick infestations. 

The terms of funding for the game fencing were based upon cost-share 

with landowners who would agree to allow the game fencing on their 

privately owned land. If it were feasible to locate fencing in a right-ofway, APHIS would need additional permits and additional funding. Many 

public utilities, such as electricity, water, telecommunications, gas lines, 

and common-carrier petroleum and petroleum-related products, are 

located within the right-of-way of roadways. Locating game fencing in the 

right-of-way would require coordination with public utility companies and 

the Texas Department of Transportation (TXDOT). Other related matters 

(as required by the terms of approval of the funding for game fencing), 

such as responsibility for fence maintenance, make this alternative 

impractical. Texas DOT does not get involved in fencing or providing 

monies toward fencing or fence maintenance. 

Several tick control methods are in early stages of study and need further 

review before their use can be approved for tick eradication. These studies 

will take years to ensure that the technology is safe and efficacious for use. 

APHIS received suggestions during the EIS public scoping meetings to 

use other methods in its efforts against cattle fever ticks. 

One method needing further study is a deer feeder device that baits deer 

with corn and treats a deer’s head and neck with permethrin when the deer 

feeds on corn from the hopper of the device. Consideration also must be 

2. Provide game 

fencing along 

the entire 500 

miles of the

Permanent 

Tick 

Quarantine 

Line

3. Locate the 

proposed tick 

control barrier 

game fencing 

in the right-ofway in the 

proposed 

locations 

along U.S. 

Hwy 83 versus 

on privately 

owned land

4. Use other tick 

control 

methods or 

technologies 

in addition to 

game fencing

44
given to the influence of this method on deer population size and 

dynamics due to the placement of corn at the feeders. The deer feeder 

devices also could contribute to attracting deer to the gap areas in the 

fencing, which could be contrary to preventing further movement of the 

ticks on host deer into the tick-free zone. Some tick control methods also 

may not be suitable for use in certain environments because of proximity 

to human populations or environmentally sensitive areas. The use of tick 

control methods in gap areas would not necessarily prevent ticks from 

being moved by deer into the tick-free zone. 

APHIS also is working with USDA’s Agricultural Research Service to 

investigate a self-medicating nutritional feed block treated with molasses 

and ivermectin for cattle that would help kill ticks that attempt to feed on 

cattle. In addition, APHIS is working with companies to test an anti-tick 

vaccine for use on cattle, specifically for use against R. annulatus, the 

cattle fever tick. These studies involve the collaboration of other agencies, 

including the U.S. Department of Health and Human Services’ Food and 

Drug Administration. 

In noting the purpose and need for the Proposed Action in this document, 

these other technologies, when available as a proven tool for the CFTEP, 

could warrant a broader programmatic evaluation in order to incorporate 

them with existing proven and other new eradication methods. Therefore, 

use of these methods could complement existing activities as well as the 

proposed game fencing. 

Work activities related to the CFTEP involve or affect other stakeholders, 

including Federal and State agencies that carry out their missions in the 

same locations5

. Although the missions of other agencies are different, the 

purpose and need for the APHIS Proposed Action to install game fencing 

could be complementary to these agencies’ missions. APHIS has 

communicated with these agencies to ensure that they are aware of the 

Proposed Action. As limited funding was specifically designated to the 

proposed installation of game fencing, any efforts of other agencies that 

would contribute to meeting the purpose and need for game fencing and 

that would make it more practical, feasible, and economical could be 

considered in the realm of APHIS implementation of the Proposed Action. 

5 For example, USDA’s NRCS, Texas’ Soil and Water Conservation Districts, USDA’s Agricultural 

Research Service, and CBP. 

5. Coordinate 

game fencing 

efforts with 

other 

agencies

45

 
U.S. Customs and Border Patrol’s (CBP) mission is to protect the U.S. 

borders from illegal immigration. APHIS informed CBP about the 

Proposed Action. The proposed game fencing does not contribute to, 

coincide with, or support CPB actions. The locations of their actions that 

have to do with a physical barrier do not coincide with the areas of the 

proposed game fencing locations. In addition, game fencing for the 

purpose of deterring the movement of white-tailed or exotic deer to 

prevent cattle fever tick infestations in the tick-free zone is different from 

the CBP Tactical Infrastructure/Border Fence and would not meet their 

needs. To ensure that game fencing would not conflict with their efforts, 

APHIS will continue to apprise CBP of the Proposed Action. 

Although Mexico is focusing tick eradication efforts in the northern states 

along the Mexico/U.S. border, funding is limited. APHIS meets with 

Mexico’s agriculture ministry, SAGARPA, bi-annually on animal disease 

concerns, including cattle fever ticks, and shares information about tick 

control options we are exploring in the United States. Challenges with tick 

eradication in northern Mexico include government cooperation with deer 

producers and acaricide resistance in the cattle fever tick populations. 

Mexico’s agriculture ministry recently revised the national tick program 

regulations by approving an official tick agreement plan; however, 

implementation throughout Mexico has not occurred yet. It likely will not 

have any effect on the cattle fever tick problem in South Texas because 

the focus will be on preventing the establishment of pesticide-resistant tick 

populations in Mexican-recognized tick-free zones. 

One purpose of the Proposed Action is to use game fencing as a tool to 

prevent cattle fever ticks from being moved by the white-tailed deer, a 

known favorable host of the ticks, beyond the Permanent Tick Quarantine 

Zone. Employing the use of an immunocontraceptive vaccine in whitetailed deer does not meet the purpose of and need for the Proposed Action. 

Although a vaccine could reduce the white-tailed deer population density, 

movement of the deer with cattle fever ticks from Mexico would continue. 

Wildlife population control can occur via lethal and non-lethal methods. In 

the areas of the Proposed Action, white-tailed deer are an important and 

valued natural resource. White-tailed deer also are important for 

recreational purposes, such as hunting, and are extremely important to the 

6. Coordinate 

tick control 

barrier game 

fencing effort 

with CBP 

efforts

7. Work with 

Federal and 

State 

agencies in 

Mexico 

8. Implement 

white-tailed 

deer and 

exotic deer 

population 

control with 

a vaccine

46
rural economy and culture of the area. Seasonal hunting of white-tailed 

deer also assists in population control. 

In deer, immunocontraceptive vaccines are intended to be used in 

combination with other wildlife management tools to control populations. 

Although some non-lethal population control could be accomplished 

solely by an immunocontraceptive vaccine that is effective for use in 

white-tailed deer, administration of a contraceptive vaccine would be 

labor-intensive, expensive, and unlikely to be successful on its own in 

resulting in any significant population control. Using an 

immunocontraceptive vaccine also would not prevent existing deer 

populations from becoming a successful host for cattle fever ticks or 

prevent other tick hosts from moving cattle fever ticks beyond the 

Permanent Tick Quarantine Zone. 

While wildlife management officials are aware of the 

immunocontraceptive vaccine option for deer, there is some resistance to 

its widespread use. Hunting advocates have questioned whether the use of 

an immunocontraceptive vaccine would replace the need for culling or 

hunting as a management tool. Some States that receive significant 

revenues from issuing hunting permits have raised similar concerns. 

APHIS continues to believe that the use of an immunocontraceptive 

vaccine in the absence of other more traditional wildlife management tools 

would not be effective in producing any significant population controls. 

Immunocontraceptive vaccines are intended to be one additional tool in 

the toolbox of wildlife management options rather than a stand-alone 

replacement for other traditional options currently in use. 

The use of immunocontraceptive vaccines in white-tailed deer is regulated 

by the U.S. Environmental Protection Agency (EPA). Registration of the 

vaccine required species-specific safety studies that were evaluated by 

EPA prior to approving the vaccine. These safety studies were conducted 

with the goal of approval for use in white-tailed deer only. If an 

immunocontraceptive vaccine for use in deer other than white-tailed deer 

were needed, additional studies would have to be conducted, submitted to 

EPA, and evaluated before it could be used. This process can be timeconsuming, and it may not be achieved prior to the timeframe in which it 

would be needed for the CFTEP. 

47
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48
III. Affected Environment

This chapter describes the existing conditions at and near the proposed 

sites for the installation of game fencing in Maverick, Starr, Webb, and 

Zapata Counties in Texas. These data and information form the basis for 

assessing the potential impacts of the action and “no action” alternative 

evaluated in chapter 4. Relevant issues evaluated in this chapter include:

• Cattle Fever Tick Resistance and Distribution

• Land Characteristics and Agricultural Production 

• Climate

• Air Quality

• Water Quality

• Vegetation

• Wildlife

• Human Health and Safety

• Cultural, Historic, and Visual Resources 

A. Cattle Fever Tick Resistance and Distribution

The CFTEP was established in 1906 to eliminate the two cattle fever tick 

species, R. microplus and R. annulatus, responsible for transmitting the 

causal agents of bovine babesiosis, B. bigemina and B. bovis, to U.S. cattle 

herds. In addition, both species are capable of transmitting the causal 

agents of bovine anaplasmosis, Anaplasma marginale, and relapsing fever, 

Borrelia theileri (Andreotti et al., 2011; Trees, 1978). Rhipicephalus 

microplus is also capable of transmitting the causal agents of B. equi to 

horses (Ueti et al., 2005). Heavy infestations of both cattle fever tick 

species can cause mechanical damage to hides, as well as compromise the 

health of the animal due to blood loss and irritation. 

The cattle fever ticks are designated as one-host ticks, which is defined as 

requiring a single host animal to complete their life cycles. Hosts include 

cattle, horses, mules, donkeys, goats, sheep, pigs, dogs, buffalo, oxen, 

several species of deer, nilgai, and antelope (Cooley 1946; Barré et al. 

2001; Ghosh et al., 2007; Cançado et al., 2009; Pound et al., 2010). 

It is important to note that in Mexico, R. microplus populations are 

resistant to at least five different classes of acaricides; however, no 

acaricide resistance has been detected so far with R. annulatus. 

49
Populations of R. microplus established in Australia are resistant to many 

different types of acaricides as well, including DDT and arsenic. More 

importantly, it is impossible to remove acaricide resistance from a tick 

population once resistance is genetically inherited and established within 

that particular tick population. Therefore, the overarching goal of the 

CFTEP is to prevent and eliminate the chance of potentially Babesiainfected and acaricide-resistant ticks becoming established in South Texas 

and perhaps the southeastern portion of the United States. 

Rhipicephalus microplus is more widely distributed throughout the world 

than R. annulatus. It is endemic to the Indian subcontinent and populations 

are established throughout tropical and subtropical regions of the world, 

including parts of northeastern Australia, southeastern Africa, and 

southern regions of South America. Rhipicephalus microplus populations 

are well-established throughout Mexico and Central America, and 

historically, populations became established in the southeastern portion of 

the United States from Florida to Texas, including Puerto Rico and the 

U.S. Virgin Islands in the Caribbean (Graham and Hourrigan, 1977). 

The distribution of R. annulatus tends to overlap with R. microplus in 

subtropical regions of the world, such as Mexico and the southeastern 

United States; however, R. annulatus populations are established 

predominately in northern and central Africa, eastern Europe, and 

countries bordering the Mediterranean Sea. Historically, in the United 

States, R. annulatus populations were established as far north as Virginia, 

Tennessee, Kansas, and southern California. Today, both species are 

periodically encountered within the Permanent Tick Quarantine Zone in 

South Texas; however, R. microplus is typically recovered from the Gulf 

Coast up to the City of Laredo, and R. annulatus is typically recovered 

from the City of Laredo up to Amistad Dam. The distribution of both 

species overlaps in Webb County, where the City of Laredo is located 

(Lohmeyer et al., 2011). 

B. Land Characteristics and Agricultural Production

“Land characteristics” as defined in this EIS include the physical features 

and soil resources within Maverick, Starr, Webb, and Zapata Counties. 

Wildlife, vegetation, water resources, air quality, human populations, and 

weather and climate patterns that may be associated with land in or near 

50
the proposed fence locations are discussed in detail in their own 

subsections of the EIS. 

The four counties lie within an area designated by NRCS as the Rio 

Grande Plain. Rio Grande Plain soils formed from sediments deposited 

over a broad coastal plain (Tinker et al., 2008). The proposed fence 

sections are limited to the Western Rio Grande Plain land resource area. 

Soils are fine to coarse-textured, well-drained, and have limited soil 

moisture for use by vegetation during the growing season (McNab and 

Avers, 1994). Soils range from alkaline to slightly acidic clays and clay 

loams. The predominant soils in the fence areas are deep clay loams and 

sandy clay loam over clay. The different physical and chemical properties 

of soils in these counties support different types of flora and fauna. For 

example, deeper soils in Texas can support tall brush, such as mesquite 

and spiny hackberry, whereas short, dense brush grows in the shallow, 

caliche (sedimentary rock) soils (TPWD, 2013 a). Drought has historically 

been a disturbance in the Rio Grande Plain, and 90 percent of the area has 

been converted from natural vegetation to dry-land pasture for cattle 

grazing (McNab and Avers, 1994). 

Maverick County is in the Western Rio Grande Plain major resource area 

(Tinker et al., 2008). Elevations range from 540 feet in the southern part of 

the county to 960 feet above sea level in the northern part. The central and 

southern parts of the county are characterized by ridges and drainages to 

the Rio Grande and the Nueces River. Terrain along the Rio Grande is 

characterized by rough hills with brush overlooking a mile-wide stretch of 

irrigated farmland (Stevens and Arriaga, 1977; TAMU, 2013). Soils are 

clay, sandy, and alluvial (composed of materials left by the water of rivers, 

floods, etc.) (TSHA, 2013). With the exception of adding height to the 

short fence already present along an irrigation canal in El Indio, we do not 

plan fencing in locations adjacent to water bodies. 

The most important natural resources in the county are soil, water, 

wildlife, petroleum, coal and natural gas. Sand, gravel and caliche are also 

available and used extensively for roads and building construction. U.S. 

Highway 277 is the major transportation route; some farm-to-market and 

county roads also serve the area. Water for residential, wildlife, 

recreational, and agricultural needs is supplied by canals from the Rio 

Grande, rivers, creeks, and other manmade ponds or bodies of water. A 

1. Maverick 

County

51
few wells draw from the Carrizo Springs Aquifer on the eastern side of the 

county (TAMU, 2013). 

Almost all crops are grown under irrigation and may include cotton, 

sorghum, alfalfa, hay, pecans, and wheat (Stevens and Arriaga, 1977; 

TSHA, 2013). In 1982, 88 percent of all land in the county was considered 

farmland and ranches, but only 2 percent of the farmland was under 

cultivation. The predominant land uses in areas adjacent to the proposed 

fence are rangeland and ranches. There are areas of irrigated crops and 

orchards, but the majority of agricultural receipts are from livestock and 

livestock products, which include cattle, milk, sheep, wool, angora goats, 

mohair, and hogs (Ochoa, 2013). The agricultural market in Maverick 

County is valued at $26.1 million (TSHA, 2013). 

Starr County is in the Sandsheet Prairie, Western, Central, and Lower Rio 

Grande Plain major land resource areas (Tinker et al., 2008). Starr County 

has elevations from 125 to 580 feet above sea level (TSHA, 2013). The 

proposed fencing is limited to flat or gently rolling rangelands in the 

Western Rio Grande land resource area. The most prominent feature is the 

line of low hills forming a boundary between the floodplain of the Rio 

Grande and the northern plain. The hill ridges are gravelly and highly 

dissected. West of Los Olmos Creek is a gently rolling plain containing 

rounded hills and broad valleys. The hills are drained by arroyos emptying 

into the Rio Grande (Thompson et al., 1972). 

Starr County has clay, loam, and sandy soils. The terrace along the Rio 

Grande contains alluvial soils. The majority of soils in Starr County are 

well suited for rangeland; some are suitable for irrigated cultivation 

(Thompson et al., 1972). 

Livestock production is the predominant means of livelihood in Starr 

County (Thompson et al., 1972). The majority of the land is used for 

agriculture, with cattle as the primary livestock, and sorghum, hay, onions, 

cantaloupes, lettuce, bell peppers, honeydew melons, and cabbage as 

primary crops. Natural resources include caliche, clay, gravel, oil, and gas. 

Gas and oil production is significant (Garza, undated). The agricultural 

market in Starr County is valued at $64.4 million (TSHA, 2013). 

Webb County is in the Northern, Central, and Western Rio Grande Plain 

major land resource areas (Tinker et al., 2008). Webb County soils are 

3. Webb 

County

2. Starr 

County

52
primarily sandy, gray soils with alluvial soils along the river. The 

proposed fencing is limited to flat or gently rolling rangelands in the 

Western Rio Grande land resource area. The county’s land surface is 

generally flat to rolling with brush. Wind action has minimized some of 

the older sedimentary deposits. Elevation ranges from 310 to 940 feet 

above sea level, and the northern and eastern sections are drained by 

creeks that eventually enter the Nueces River; the southern and western 

parts of the county are drained by the Rio Grande (Leffler and Long, 2013; 

TSHA, 2013). There are estimated to be more than 2,500 ponds and lakes 

in Webb County (Sanders and Gabriel, 1985). We do not plan fencing in 

locations adjacent to water bodies. 

Mineral resources include caliche, clay, uranium, oil, natural gas, and 

zeolite (commonly used as an adsorbent). Webb County was first in the 

State in production of natural gas (Leffler and Long, 2013). 

Cattle ranching and the oil and gas industry are integral to the county’s 

economy, and the majority of the county's land is devoted to agriculture, 

including ranching. Principal crops include vegetables, sorghum, cotton, 

and hay. Crops and pasture grasses are grown using irrigation water from 

the Rio Grande (Leffler and Long, 2013). The agricultural market in Webb 

County is valued at $24.7 million (TSHA, 2013).

Zapata County occupies two major land resource areas: Western and 

Central Rio Grande Plain (Tinker et al., 2008). The prevailing landscape 

consists of inland, dissected coastal plains. Most of the area is similar to 

rolling brushy prairie, with elevations from 300 to 860 feet above sea level 

(Garza and Long, undated; TSHA, 2013). The proposed fencing is limited 

to flat or gently rolling rangelands in the Western Rio Grande land 

resource area. 

Zapata County generally has light-colored loam over reddish or mottled 

clay subsoils; limestone lies in places within 40 inches of the surface 

(Garza and Long, undated). Soils in Zapata County are well suited for 

rangeland, wildlife habitat, livestock production, and forage production 

(Molina and Guerra, 2011). 

The most important natural resources in the county are soil, water, 

wildlife, petroleum, and natural gas. Other natural resources include clay, 

lignite coal, sand, gravel, and caliche – the last three are used extensively 

to construct roads and buildings (Garza and Long, undated). 

4. Zapata 

County

53
Water for residential, wildlife, recreational, and agricultural needs is 

supplied by the Rio Grande, Falcon Reservoir, and other manmade wells 

or bodies of water. Most crops are grown under irrigation and may include 

cotton, corn, cantaloupes, watermelons, onions, tomatoes, peppers, 

cabbage, spinach, herbs and sorghum. Raising beef cattle is a major 

agricultural enterprise in the county, involving careful management of 

available rangeland, pastureland, and hayland. Rangeland or native 

grassland, unlike pasture or hayland, receives no regular cultural 

treatment, such as irrigation, fertilizer, weed control, or tillage (Garza and 

Long, undated). The agricultural market in Zapata County is valued at 

$13.1 million (TSHA, 2013). 

C. Climate 

The climate in Maverick, Webb, Starr, and Zapata Counties is considered 

subtropical. Temperatures in the summer are hot, with average high 

temperatures near 100 degrees Fahrenheit. Winter weather is mild, with 

average minimum temperatures near 45 degrees Fahrenheit. Precipitation 

averages 20 inches annually, with more precipitation in the summer than 

in the winter (figure 3-1). A southerly wind is the predominant wind 

condition in South Texas. In most areas of the State, the average wind 

speeds are between 7 and 15 miles per hour (Bomar, 2008). 

D. Air Quality

The CAA (42 U.S.C. §§ 7401 et seq.) is the primary Federal legislation 

that addresses air quality. In a given region or area, air quality is measured 

by the concentration of pollutants in the atmosphere, and is influenced by 

surface topography and prevailing meteorological conditions. The EPA 

established National Ambient Air Quality Standards (numerical 

concentration-based standards) for six criteria pollutants that impact 

human health and the environment (40 CFR § 50). These pollutants are 

common and accumulate in the atmosphere as a result of normal levels of 

human activity. They include carbon monoxide (CO), nitrogen dioxide 

(NO2), ozone (O3), sulfur dioxide (SO2), small particulate matter, and lead 

(Pb). 

Pollutant emission types are categorized as either primary or secondary (§ 

50). Primary standards represent maximum levels of background air 

54
pollution that are considered safe for humans, including sensitive groups 

such as asthmatics, children, and the elderly. Secondary standards provide 

public welfare protection, including the protection of animals, vegetation, 

crops, and other public resources (EPA, 2012). Table 3-1 indicates the 

primary and secondary National Ambient Air Quality Standards. 

Figure 3-1. Average temperature and precipitation in South Texas, 1971-2000. 

Credit: Southern Regional Climate Center.

Ozone, a criteria pollutant, is formed in the atmosphere by photochemical 

reactions involving sunlight and oxides of nitrogen (NOx) and volatile 

organic compounds (VOCs). Major sources of NOx and VOCs include 

industrial facilities, electric utilities, motor vehicle exhaust, gasoline 

vapors, and chemical solvents (EPA, 2012). Regulatory agencies limit 

atmospheric ozone concentrations by controlling the release of VOCs and 

NOx. 

55
Table 3-1. Primary and Secondary National Ambient Air Quality Standards 

(40 CFR § 50)

1,2

Pollutant Averaging Time Standard Value3 Standard Type

Carbon Monoxide (CO) 8-hour 9 ppm Primary 

1-hour 35 ppm Primary 

Lead (Pb) Rolling 3-month 

average

0.15 μg/m4 Primary and 

Secondary

Nitrogen Dioxide (NO2) 1-hour3 100 ppb Primary

Annual 53 ppb Primary and 

Secondary

Ozone (O3) 8-hour 0.075 ppm5 Primary and 

Secondary

Particulate Matter <2.5 

Micrometers (PM2.5) 

Annual 15 μg/m4 Primary and 

Secondary

24-hour 35 μg/m4 Primary and 

Secondary

Particulate Matter <10 

Micrometers (PM10) 

24-hour 150 μg/m4 Primary and 

Secondary

Sulfur Dioxide (SO2) 1-hour 75 ppb6 Primary

3-hour 0.5 ppm Secondary 1

As of October 2011.

2

These EPA standards (promulgated pursuant to section 109 of the CAA (40 CFR § 50)), 

were adopted by Texas in 1976, effective 1979 (30 TAC 101.21).

3

ppm – parts per million; ppb – parts per billion; mg/m3 – milligrams per cubic meter; 

μg/m3

 – micrograms per cubic meter. 4

In February 2010, EPA established a new 1-hour standard at a level of 0.100 ppm, based 

on the 3-year average of the 98thpercentile of the yearly distribution concentration, to

supplement the existing annual standard. 5

The 1997 ozone standard (0.08 ppm, annual fourth-highest daily maximum 8-hour 

concentration, averaged over 3 years) and related implementation rules remain in 

place. In 1997, EPA revoked the 1-hour ozone standard (0.12 ppm, not to be exceeded 

more than once per year) in all areas, although some areas have continued obligations 

under that standard (“anti-backsliding”). The 1-hour ozone standard is attained when the 

expected number of days per calendar year with maximum hourly average concentrations 

above 0.12 ppm is less than or equal to 1. 6

In June 2010, EPA established a new 1-hour SO 2 standard at a level of 75 parts per 

billion (ppb), based on the 3-year average of the annual 99th

percentile of 1-hour daily 

maximum concentrations. 

56
Particulate matter emissions can have different health effects depending 

on the particle size; therefore, EPA developed separate National Ambient 

Air Quality Standards for coarse particulate matter (PM10) and fine 

particulate matter (PM2.5) (40 CFR § 50, Appendices I-L). Fine particulate 

matter, also known as a primary pollutant, is emitted from sources such as 

diesel engines, power plants, and refineries as a fine dust or liquid mist 

(soot). This matter can become a secondary pollutant as a result of a 

chemical reaction between two primary pollutants by forming nitrate and 

sulfate compounds. Precursors of fine particulate matter include SO2, NOx, 

VOC, and ammonia. Metropolitan areas have greater levels of PM2.5 than 

other areas of the country (figure 3-2). 

Figure 3-2. Global satellite-derived map of fine particulate matter (PM2.5) from 

2001-2006. Credit: National Aeronautics and Space Administration.

Greenhouse gases are gases emitted from natural processes and human 

activities that trap heat in the atmosphere. While greenhouse gases help 

regulate the earth’s temperature, they also contribute to global climate 

change. Greenhouse gases consist of water vapor, carbon dioxide (CO2), 

methane, NO, O3, hydrocarbons, and chlorofluorcarbons. 

57
On February 18, 2010, CEQ issued a draft guidance memorandum 

advising Federal agencies to consider whether analysis of the direct and 

indirect greenhouse gas emissions from an agency’s proposed actions may 

provide meaningful information to decision makers and the public (CEQ, 

2010). If a proposed action would be reasonably anticipated to cause direct 

emissions of 25,000 metric tons or more of CO2-equivalent greenhouse 

gases on an annual basis, agencies should consider this an indicator that a 

quantitative and qualitative assessment may be meaningful. CEQ also 

encourages Federal agencies to consider whether the action’s long-term 

emissions should receive similar analysis, even if the annual direct 

emissions of CO2-equivalent greenhouse gases are less than 25,000 metric 

tons (CEQ, 2010). This serves as a baseline for the minimum level of 

greenhouse gas emissions from an action that may warrant further 

discussion in the NEPA analysis. 

To enforce requirements under the CAA, the EPA has delegated 

responsibility for ensuring compliance of the National Ambient Air 

Quality Standards to States and local agencies. The Texas Commission on 

Environmental Quality (TCEQ) is the State agency responsible for 

monitoring and regulating air quality. Maverick, Webb, and Zapata 

Counties are within Region 16 of the TCEQ Air Quality Control Area, 

while Starr County is in Region 15 (figure 3-3). 

 

TCEQ collects data for the Texas Air Quality Index based on EPA 

standards; small particulate matter and ozone because are the two 

pollutants that pose the greatest threat to human health. According to 

TCEQ, scores for Maverick, Starr, Webb, and Zapata Counties typically 

fall in the “good” range and occasionally in the “moderate” range. The 

major sources of air pollution in these counties are highway vehicle traffic, 

petroleum production, and agriculture (TCPS, 1995). The South Texas 

counties have better air quality than many of the other major urban areas 

around the State, which more often see Air Quality Indices in the 

“moderate” range and “unhealthy for sensitive groups” range (Combs, 

2008). 

58
Figure 3-3. TCEQ Air Quality Control Areas. Credit: TCEQ. 

E. Water Quality

The proposed CFTEP fence is located within the central portion of the Rio 

Grande watershed. A “watershed” is an area of land that contributes water 

to a river or stream. The project area includes a total of 27 reservoirs, 

streams, rivers, ephemeral (short-lived), intermittent, and perennial 

drainage features that are considered jurisdictional waters of the United 

States and are subject to CWA regulations (40 CFR §§ 136, 230-233) (see 

Appendix I). The major water bodies of this watershed include the Rio 

Grande bordering the west or southwest of all four counties, the Main 

Canal in Maverick County, Falcon Dam on the west border of Zapata and 

Starr Counties, and Falcon Reservoir and its three arms that extend into 

Zapata County (Arroyo Burro, Arroyo del Tigre Grande, and Arroyo del 

Tigre Chiquito). Minor water bodies include streams and arroyos 

(table 3-2). 

59
Table 3-2. Jurisdictional and Non-Jurisdictional Water Bodies

 Along the Proposed Fencing Area

 (APHIS & EPA Office of Water) 

County Water Body

Maverick1 

Rosita Creek

Cuevas Creek

Cuervo Creek

Starr2 

Arroyo Minita

Arroyo del Tigre

Arroyo de Los Mudos

Webb3 Carricitos Creek

Zapata4 

Dolores Creek

Arroyo Salado

Arroyo San Francisco

El Grullo Creek

Marcial Creek

Arroyo Zacatosa

Chapote Creek

Arroyo Molletes

Arroyo Ranchito

Arroyo San Bartolo

Falcon Reservoir

Arroyo Clareno

Arroyo del Tigre Grande

Arroyo del Tigre Chiquita

Arroyo Los Guajes

Arroyo Tinajas

1

Maverick County has four unnamed streams near the proposed fencing area.

2

Starr County has two unnamed streams near the proposed fencing area. 3

Webb County has four unnamed streams near the proposed fencing area.

4

Zapata County has five unnamed streams near the proposed fencing area.

States are required to monitor and regulate water quality in their rivers and 

streams under Section 303(d) of the CWA (40 CFR § 131). If a water 

body is deemed impaired by the State, this means that it does not meet a 

particular water quality standard. In Texas, water quality standards are 

established by TCEQ. Water bodies identified as impaired are targeted for 

pollution management under the TCEQ Continuing Planning Process 

(TCEQ, 2013). Although segments of the Rio Grande basin (immediately 

downstream of Del Rio and Laredo) are listed in the 2010 State of Texas 

CWA Section 303(d) List, the fence will only come in close proximity to a 

60
303(d) impaired water designated “TX-2304” just south of Ramireno, 

Texas. Construction will not occur over or in this water body (TCEQ, 

2011). 

The Rio Grande and Falcon Reservoir provide much of the public water 

supply in the project area. However, because of the rural nature of the 

project area, we believe that private wells also provide water. The Texas 

Water Development Board’s Water Information Integration Dissemination

System identifies water wells within the region and along U.S. Highway 

83 (FHWA, 2007). 

The proposed tick fence is located in an area that is not supported by any 

major or minor aquifers (George et al., 2011). The southwestern extents of 

the Carrizo-Wilcox and Gulf Coast aquifers are located to the north and 

south of the project area, respectively. 

The proposed project would cross 100-year floodplains in 12 locations in 

three counties (Starr, Webb, and Zapata), as identified by the Federal 

Emergency Management Agency (table 3-3; Appendix I). 

The proposed project is located in Maverick, Starr, Webb, and Zapata

Counties, which are not coastal counties. Therefore, the project is not 

under the jurisdiction of the Texas Coastal Management Program and 

would not require coordination under the Texas Coastal Management 

Program rules. However, stormwater runoff in the project area flows into 

the Rio Grande basin, and therefore, APHIS should contact TCEQ 

regarding the potential need to work under the Texas Pollutant Discharge 

Elimination System Construction General Permit and the need for a 

Stormwater Pollution Prevention Plan (TCEQ, 2013). 

Of the 27 bodies of water identified in the project area, 25 consist only of 

defined channels with no wetland component. Many of these are 

ephemeral (a channel that only holds water during and immediately after 

rain events) arroyos that begin as headwaters on hillsides. Others are 

intermittent (a stream that holds water during wet times of the year) and 

perennial (a stream that holds water throughout the year) features that 

contain water during part or most of the year. Eighteen of the 

arroyos/streams have defined channels that vary from 1 to 6 feet wide at 

the ordinary high water mark. These arroyos include Arroyo Zacatoso, 

Chapote Creek, Arroyo Clareno, Arroyo del Tigre, and 14 unnamed 

tributaries (FHWA, 2007). Four arroyos/streams have defined channels 

1. Arroyos/

Streams 

with 

Defined 

Channels

61
that vary from 8 to 20 feet wide at the ordinary high water mark. These 

larger arroyos include Arroyo San Bartolo, Arroyo los Guajes, Arroyo la 

Minita, and one unnamed tributary. 

Table 3-3. Water Bodies in 100-year Floodplain

(TXDOT in FHWA, 2007)

County Water Body

Starr Arroyo Minita

Arroyo del Tigre

Webb Carricitos Creek

Zapata Arroyo Burro

Arroyo Molletes

Arroyo Ranchito

Arroyo San Bartolo

Falcon Reservoir

Arroyo Clareno

Arroyo del Tigre Grande

Arroyo del Tigre Chiquita

Arroyo Los Guajes

Several drainage features in the project area do not exhibit defined 

channels but convey water through the project area via sheet flow. The 

portions of these drainages located in the project area are not considered 

jurisdictional under the CWA (40 CFR §§ 136, 230-233). Some of these 

features, such as Arroyo Tinajas and Arroyo de los Mudos, are relatively 

large and have floodplains associated with them that drain the project 

region (FHWA, 2007). 

There are two wetlands in the project area subject to regulations under the 

CWA (§§ 136, 230-233). These aquatic sites are associated with Arroyo 

Molletes and Arroyo Ranchito, which are located 1 mile north of the city 

of Zapata, just west of U.S. Highway 83. At Arroyo Molletes, the total 

area of wetland in the proposed fence area is 0.1 acre. This wetland is 

located west of U.S. Highway 83 in the right-of-way. At Arroyo Ranchito, 

approximately 0.14 acre of wetland is located west of U.S. Highway 83 in 

the right-of-way. 

The proposed project would come up to but not cross three arms of the 

Falcon Reservoir: Arroyo Burro, Arroyo del Tigre Grande, and Arroyo 

del Tigre Chiquito. Although most of the area located within these arms is 

2. Arroyos/

Streams 

without 

Defined 

Channels

3. Jurisdictional 

Wetlands

4. Open 

Water

62
dry (FHWA, 2007), the U.S. Army Corps of Engineers maintains 

jurisdiction of these navigable waters. 

Stock Tank – The 2007 Texas U.S. Highway 83 study (FHWA, 2007) 

found that a man-made stock tank is located on the east side of the 

highway, approximately two miles north of Falcon. This stock tank is 

approximately 0.13 acre and is used for agricultural activities. The tank is 

not associated with any defined stream channel or floodplains. Water is

pumped into the stock tank from a well or water pipeline, and overflow 

drains into the U.S. Highway 83 roadway drainage ditches. This stock tank 

is not considered a jurisdictional water of the United States and is not 

subject to the CWA (§§ 136, 230-233). 

Isolated Wetland – The 2007 U.S. Highway 83 Texas study (FHWA, 

2007) also found one isolated wetland near U.S. Highway 83 immediately 

south of FM 2098 (South). This wetland is approximately 0.08 acre and is 

in a depression that receives water from an overflow pipe that releases 

water from a rural Falcon water supply corporation storage tank 

(standpipe). This wetland is not connected to any defined stream channel 

and is not located within any floodplains. This isolated wetland is not 

subject to regulations under the CWA (§§ 136, 230-233). 

F. Vegetation

The affected environment discussed in this document occurs within a 

distinct ecoregion (McMahan et al., 1984) known as South Texas Brush 

Country (TPWD, 2013 a), South Texas Plains, or the Rio Grande Plains 

(Bailey, 2009) (figure 3-4). It is an arid expanse of Texas that begins south 

of San Antonio and extends down to the Rio Grande. This region 

encompasses about 20.5 million acres, covering much of southwest region 

of the State (Taylor et al., 1997). Some ecologists consider the South 

Texas Brush County to be a biologically diverse region that supports a 

wide array of wildlife species ranging from migratory birds to more 

permanent residents such as ocelots and white-tailed deer (Maywald and 

Doan-Crider, 2008). 

5. Isolated 

Features

63
Figure 3-4. Ecoregions of Texas, as described by R.G Bailey (1995).

Present in the South Texas Brush County are elements of the Chihuahuan 

Desert to the west, the Tamaulipan thornscrub and subtropical woodlands 

along the Rio Grande, and the coastal grasslands to the east. These 

elements include arid to semi-arid landscapes that feature a limited 

number of ephemeral wetlands, and distinct examples of the conversion of 

grasslands and savannas to woodlands. The Chihuahuan Desert features a 

series of lower basin slopes and basin floors and is considered cool 

compared to other deserts located in the Western Hemisphere (average 

temperature of 65.5 degrees Fahrenheit), receiving higher rates of rainfall 

than other warm desert ecoregions (average annual rate of 5.9 inches to 

15.7 inches). The region is isolated from other arid regions such as the 

Sonoran Desert by the large mountain ranges of the Sierra Madres, which 

has allowed the evolution of many native plant species that are restricted 

to the Chihuahuan Desert. The Tamaulipan thornscrub features a 

subtropical climate and consists of drought-tolerant woody plants that 

grow to heights up to 9 feet. These plants tend to cluster into dense 

64
thickets that can cover up to 75 percent of the ground in some areas 

(McMahan et al., 1984), with the densest areas limited to the western 30 to 

50 percent of Starr County. The coastal grassland to the east of the South 

Texas Brush County is a grassland ecoregion featuring a mix of tallgrass 

prairie similar to that found in inland Texas. 

The native plant communities of this ecoregion have been shaped by 

natural features, including rainfall rates and long growing seasons, 

averaging 340 to 360 days each year (Taylor et al., 1997). Much of the 

vegetation found in this ecoregion features small leaves and thorns, typical 

of xerophytic (drought-tolerant) brush communities. Though recurrent 

droughts are typical, the region boasts the longest growing season in 

Texas. 

 

Human activity (since European colonization) also has had a tremendous 

impact on the landscape (McMahan et al., 1984) via brush control and 

grazing practices associated with cattle ranching. Shrub species such as 

blackbrush, palo verde, and allthorn that were previously restricted to 

thickets, upland areas, major drainages, and river bottoms are now 

prevalent in this region due to land use practices of early settlers, primarily 

through the installation of fencing and fire suppression. Cattle have grazed 

this region since the late 1800s, and the region has experienced a 

23 percent increase in woody cover since 1941 (Council, 1994). 

Additionally, soil compaction and periodic droughts have aided a gradual 

migration of brush species into open grassland. 

Within Maverick, Starr, Webb, and Zapata Counties, two vegetation types 

are dominant: ceniza-blackbrush-creosote, which is found on the slopes of 

the Rio Grande basin, from near Langtry in Val Verde County to near San 

Ygnacio in Zapata County, and mesquite-blackbrush, which is found 

principally on shallow, gravelly, or loamy soils and is common to the 

South Texas Plains. The plants commonly associated with each vegetation 

type are listed in table 3-4. 

Within the affected environment, efforts to restore native species of the 

South Texas Brush Country are ongoing and include planting native 

grasses and forb (herbaceous flowering plant) species in upland habitat 

(FWS, 2006). One such project taking place within the Tamaulipan 

thornscrub ecoregion of Starr County focuses on the star cactus 

(Astrophytum asterias) (FWS, 2003). Habitat destruction and years of 

1. Current 

Restoration 

Activities

65
Table 3-4: Predominant plants of the ceniza-blackbrush-creosote (C-B-C) 

and mesquite-blackbrush (M-B) communities (Bailey, 2009) 

Common Scientific Present in

C-B-C

Present in

M-B

Allthorn Koeberlinia spinosa Yes Yes

Bluewood Condalia hookeri No Yes

Catclaw acacia Acacia greggii Yes No

Catclaw mimosa

Ceniza

Mimosa biuncifera

Leucophyllum frutescens

No

No

No

Yes

Coldenia Coldenia spp. No No

Curly mesquite Hilaria belangeri Yes No

Desert Olive Forestiera angustifolia No Yes

Desert Yaupon Shaefferia cuneifolia Yes Yes

Dogweed Dyssodia pentachaeta var. pentachaeta No Yes

Goatbush Castela texana Yes No

Granjeno Celtis pallid No Yes

Guajillo Acacia berlandieri Yes Yes

Guayacan Porlieria angustifolia Yes Yes

Hairy grama Bouteloua hirsute No Yes

Hairy tridens Frioneuron pilosum Yes Yes

Kidneywood Eysenhardtia texana Yes Yes

Knotweed leafflower Phyllanthus polygonoides No Yes

Leatherstem Jatropha dioica No Yes

Lotebush Ziziphus obtusifolia Yes Yes

Mat euphorbia Euphorbia serpens No Yes

Mesquite Prosopis glandulosa Yes No

Paloverde Cercidium texanum Yes No

Pink pappusgrass Pappophorum bicolor Yes Yes

Purple three-awn Aristida purpurea No Yes

Slim tridens Tridens muticus var. muticus Yes Yes

Sotol Dasylirion spp. Yes

Tasajillo Opuntia leptocaulis No Yes

Texas grama Bouteloua rigidiseta Yes No

Texas pricklypear Opuntia lindheimeri Yes Yes

Two-leaved senna Cassia roemeriana Yes Yes

Whitebrush Aloysia gratissima No Yes

Yucca Yucca spp. Yes Yes

over-collection by cactus enthusiasts have led to the listing of this species 

as endangered by FWS (58 FR 53804-53807 (1993); 50 CFR § 17.12(h)). 

All known locations of the star cactus occur on 20 acres of privately 

owned land. 

Restoration efforts include a monitoring plan for more than 300 

transplanted individuals over a 10-year period, beginning in 2012. 

Because there are currently no known Federal- or State-owned properties 

with star cactus, the conservation and preservation of these populations on 

private land is crucial in preventing extinction of this species from Texas. 

The construction of fence portions in Starr County will not impact these 

66
conservation efforts since the nearest restoration site is more than 9 miles 

from the proposed fence location (figure 3-5). 

Figure 3-5. Map depicting the distance between the nearest star cactus 

restoration site and the location of the proposed fence. (The red line 

depicts the proposed fencing location, and the blue line indicates the 

distance between the fence and the critical habitat for the star 

cactus.) Credit: USDA, APHIS. 

Ecosystems are defined by interactions between organisms and their 

environment. In South Texas, native plants are critical to the overall 

resilience and stability of the region and are a critical component of the 

ecosystem function, which in turn maintains greater levels of species 

biodiversity, especially of birds (Karr and Roth, 1971; MacArthur and 

MacArthur, 1961; Maywald and Doan-Crider, 2008; Roth, 1976; Willson, 

1974). Invasive species can disrupt the balance in an ecosystem by 

outcompeting native species and changing the way in which nutrients and 

water are cycled (Sands et al., 2009). Invasive species represent one of the 

greatest threats to rangelands, degrading ecosystem productivity and 

reducing biodiversity (Mullin et al., 2000). 

Biodiversity describes the variety of plant, animal, and microbial life 

found within an ecosystem. Biodiversity is considered an important 

component of ecosystem function (Loreau et al., 2002). Deserts and other 

arid environments are better able to sustain critical ecosystem functions 

when they contain a greater variety of plants (Maestre et al., 2012). For 

example, communities with a greater number of plant species are more 

resistant to drought. When invasive plants establish within an ecosystem, 

2. Invasive 

Vegetation

67
the number of different plant species characterizing a native plant 

community changes, causing a reduction in biodiversity, and in turn, 

reducing ecosystem function. Reductions in biodiversity can often result in 

long-term and often irreversible habitat degradation by disrupting 

ecosystem processes, such as nutrient cycling and soil stability (Sands et 

al., 2009). 

Native plant species vary in timing of growth, seed, and fruit production, 

which subsequently provides food and shelter for herbivores such as the 

white-tailed deer and northern bobwhite quail at different times during the 

year (Arredondo et al., 2007; Sands et al., 2009). The environmental 

changes related to the presence of exotic (native in a country other than 

the United States) vegetation can have negative impacts on both plant and 

animal communities. For example, Flanders et al. (2006) identified 

reduced numbers of birds and insects within habitats where exotic grass 

displaced native grasses. This is primarily driven by a reduction in the 

species diversity of native plant communities. Exotic plant species tend to 

invade areas of recent disturbance including areas cleared for fence

construction and maintenance. 

Buffelgrass (Pennisetum ciliare) is an invasive plant species common to 

South Texas. Sands et al. (2009) observed that increasing abundance of 

buffelgrass indicated lower abundance of native grass coverage and 

diversity. Dense monocultures of exotic grasses, such as buffelgrass, can 

displace native grass species, reducing ecosystem function and increasing

the frequency and intensity of fires on the landscape (Sands et al., 2009). 

Native to Africa, buffelgrass has the ability to tolerate extremely hot and 

dry conditions and does well under a frequent fire regime. It also produces 

many seeds and is considered an aggressive colonizer. 

In response to an extended period of drought in the early 1950s, ranchers 

began to plant buffelgrass seed as a “high producing, nutritious forage 

grass... [that could allow] for the advancement of livestock ranching in 

the region” (Hanselka, 1988) and fill the void left by the low quality yields 

of less drought-tolerant grass species. Subsequent to root plowing, many 

ranchers seeded their rangelands with the perennial bunchgrass (grasses 

that grow in clumps). This practice continues in the United States and 

Mexico to support livestock (Hoyt, 2006). 

68
Table 3-5. List of exotic invasive plant species known to inhabit Maverick, 

Starr, Webb, and Zapata Counties, Texas (TIPPC, 2011)

Common Name Scientific Name Maverick Webb Zapata Starr 

Bermudagrass Cynodon dactylon N Y N N

Buffelgrass Pennisetum ciliare Y Y Y Y

Castorbean Ricinus communis N N Y N

Chinaberrytree Melia azedarach Y Y Y N

Common dandelion Tarazacum officinale Y N N N

Dallisgrass Paspalum dilatatum N N N Y

Fivestamen tamarisk Tamarix chinensis N Y Y N

French tamarisk Tamarix gallica N Y N N

Giant reed1 Arundo donax Y Y Y Y

Johnsongrass Sorghum halepense Y Y N N

Kleberg's bluestem Dichanthium annulatum N N N Y

Lehmann lovegrass Eragrostis lehmanniana Nees N Y N Y

Maltese star-thistle Centaurea melitensis Y Y N N

Nutgrass Cyperus rotundus N Y N Y

Palay rubbervine Cryptostegia grandiflora N N N Y

Pampas grass Cortaderia selloana N N N Y

Puncturevine Tribulus terrestris N Y N Y

Russian thistle Salsola tragus N Y Y Y

Saltcedar1 Tamarix ramosissima N Y Y N

South American

mock vervain

Glandularia pulchella N Y Y Y

Tree tobacco Nicotiana glauca N Y Y Y

Vasey's grass Paspalum urvillei N N N Y

White horehound Marrubium vulgare Y N N N

White leadtree Leucaena leucocephala N Y Y N

White mulberry Morus alba N Y Y N

Yellow sweetclover Melilotus officinalis N Y N N

1

Giant reed and saltcedar are listed by the State of Texas as noxious weeds (4 TAC 

§19.300 (a)).

G. Wildlife

Maverick, Starr, Webb, and Zapata Counties are located in the South 

Texas Wildlife Management Area. This area has long been noted for its 

cattle industry and abundant wildlife. During the 1600s and 1700s, there 

was some natural grazing pressure on this area with buffalo, antelope, and 

deer as the predominant ungulates (TPWD, 2013 b). In the 1800s, South 

Texas became colonized, livestock quantities grew, and fences were built 

69
to contain the livestock. These activities resulted in an increase in grazing 

pressure, a decrease in the occurrence of natural fires, an increase in brush 

(TPWD, 2013 b), and an overall reduction in plant and animal species 

diversity (Kozicky and Fulbright, 1991). Beginning in the 1960s, wildlife 

biologists began to make an effort to control brush while minimizing 

negative impacts to wildlife. The trend of habitat improvement and 

restoration continues today. 

Despite the changes in vegetation, the South Texas Brush Country has 

more biodiversity than any other ecoregion in Texas (TEA, 2010) due to 

the distinctive Rio Grande Valley Region (TPWD, 2013 b). Unique 

species such as the ocelot, jaguarundi, ferruginous pygmy-owl, green jay, 

elf owl, Texas tortoise, indigo snake, and Mexican burrowing toad have 

been observed in this ecoregion (TPWD, 2013 a). 

Maverick, Starr, Webb, and Zapata Counties are situated in the 

Tamaulipan Brushlands Bird Conservation Region (NABCI, undated & 

supp. 2000). The biodiversity in this region is primarily influenced by 

variability in temperature, soils, and precipitation. Within Maverick, Starr, 

Webb, and Zapata Counties, 351 avian species have been observed since 

January 2000. Spring migration typically results in 309 species moving 

through the area while fall migration accounts for the movement of 291 

species. One hundred and sixty-seven of these species have the potential to 

breed in these counties (78 species Maverick; 148 species Starr; 117 

species Webb; 95 species Zapata), and 283 species overwinter here (eBird, 

2012). 

The South Texas Wildlife Management Area, which covers 

5,255,676 acres, boasts premium deer habitat resulting in trophy whitetailed deer (Odocoileus virginianus) (Cain, 2012; Davis, 1990; TPWD, 

2013 b). From 2005 to 2010, however, the number of deer decreased from 

19 deer/ acre to 13 deer/ acre. In addition, the number of does per buck 

decreased from 4.14 to 1.83; the number of fawns experienced similar 

decreases (Cain, 2012). According to the Big Game Harvest Survey 

Results generated by the Texas Parks and Wildlife Department (Purvis, 

2012), 68 percent of hunters were successful in harvesting 112,139 deer 

from 2010-2011 in the South Texas Brush Country. 

While commonly located in the Trans Pecos, some mule deer (Odocoileus 

hemionus crooki) are located in the western South Texas Brush Country. 

1. Birds

2. Big Game 

Species

70
Mule deer are dependent upon forbs, so their populations decline during 

years of drought. This species also is susceptible to overgrazing and brush 

encroachment. Mule deer, unlike white-tailed deer, prefer open rangeland 

(TPWD, undated a). Approximately 25 percent of hunters were successful 

in harvesting 136 mule deer in the South Texas Brush Country during the 

2010-2011 hunting season (Purvis, 2012). 

Peccaries, or also known as javelinas, are found in arid or semi-arid parts 

of the State with most located in the South Texas Brush Country, the 

Trans-Pecos’ desert grasslands, and the Edwards Plateau’s oak-juniper 

woodlands. This species has a limited home range and is active in the 

early morning and late afternoon during the winter; the species becomes 

nocturnal when the temperature increases (TPWD, undated a). 

Approximately 15,938 javelinas were harvested from 2010-2011 with 

72 percent hunter success (Purvis, 2012). It is important to note that some 

hunters may confuse feral swine with javelinas. 

Texas has more non-native species and greater numbers of non-native 

species than any other State. Approximately 70 percent of these species 

are confined on pastures by game-proof fences, and the remaining 

30 percent are free range. Surveys for non-native species began in the 

1960s, with 13 species and 13,000 individuals identified. The last survey 

was conducted in 1996 and at that time, there were 190,000 individuals 

from 76 different species (Sheffield, 2013). The most numerous nonnative species in Texas include nilgai antelope (from India), sika deer 

(Southeast Asia), mouflon sheep (Sardinia and Corsica), fallow deer (Asia 

Minor and southern Europe), and feral swine (Europe) (Sheffield, 2013). 

South Texas is host to approximately 18 percent of the non-native species 

in Texas (Sheffield, 2013). 

Nilgai antelope (Boselaphus tragocamelus) were introduced into Texas in 

the 1940s (Sheffield et al., 1983) and are the most abundant free-ranging 

ungulate in South Texas (Bradley, 1997) with population estimates of 

more than 36,000 individuals (Traweek and Welch, 1992). Nilgai 

antelopes also are potential carriers of the cattle fever tick (CardenasCanales et al., 2011; Moczygemba et al., 2012). Nilgai populations are 

highly mobile and can shift home ranges under pressure. They are a large 

species (males weigh in excess of 600 pounds) and can easily compete 

with cattle and native deer (Bradley, 1997; Moczygemba et al., 2012). 

White-tailed deer prefer forbs and browse (leaves of woody plants) and 

3. Non-native 

Species

71
consume little grass. If forbs and browse become scarce from competition 

or weather-related events, exotics have the ability to shift their diet to 

grass whereas white-tailed deer are unable to do this and subsequently can 

suffer from malnutrition. The ability of nilgai to consume a variety of 

resources also can have an impact on the carrying capacity of a range 

(Armstrong and Harmel, 1981). 

Feral hogs (Sus scrofa) in Texas are domestic hogs that escaped or were 

released for hunting purposes. Feral hogs are located throughout Texas, 

with the greatest population densities in East, South, and Central Texas. 

The estimated population of feral hogs in Texas is 1.5 million. Feral hogs 

are successful due to limited natural predators and high reproductive 

potential. Feral hogs compete with livestock, game, and non-game wildlife 

species for food and are responsible for destruction of habitat and damage 

to agriculture commodities (Taylor, 2003). 

Federal agencies must ensure their actions are not likely to jeopardize the 

continued existence of endangered or threatened species or result in the 

destruction or adverse modification of critical habitat (50 CFR § 402). 

Eight federally listed species and one candidate for listing occur in the 

four counties (Maverick, Starr, Webb, and Zapata). Thirty-two state-listed 

species (table 3-6) and 37 species of concern (table 3-7) are also listed in 

the four counties. Texas laws and regulations prohibit commerce or 

collection from public lands of state-listed plants, or the taking, 

possession, transportation, and sale of any state-listed animal species 

without the issuance of a permit by the Texas Parks and Wildlife 

Department. Species of concern is an informal term used to describe 

species that may have declining populations, but they do not receive 

protection from Federal or State laws. 

Federally listed endangered species in the four counties include the ocelot 

(Leopardus (=Felis) pardalis), Gulf Coast jaguarundi (Herpailurus 

(=Felis) yagouaroundi cacomitli), least tern (interior population) (Sterna 

antillarum), Ashy dogweed (Thymophylla tephroleuca), Johnston’s 

frankenia (Frankenia johnstonii), Zapata bladderpod (Lesquerella 

thamnophila) and its designated critical habitat, Star cactus (Astrophytum 

asterias), and Walker’s manioc (Manihot walkerae) (FWS, 2013). The 

Texas hornshell (Popenaias popei) is a candidate for federal listing. 

4. Threatened 

and 

Endangered 

Species

72
Table 3-6. State-listed Species (excluding federally listed species 

discussed above) in Maverick, Starr, Webb, and Zapata

Counties (TPWD, 2012) 

Category Scientific Name Common Name

Mammals Nasua narica White-nosed coati

Oryzomys couesi Coues’ rice rat

Canis lupus Gray wolf

Birds Falco peregrinus anatum American peregrine falcon

Glaucidium brasilianum 

cactorum Cactus ferruginous pygmy-owl

Buteogallus anthracinus Common black-hawk

Asturina nitida Gray hawk

Camptostoma imberbe Northern-beardless-tyrannulet

Falco peregrines Peregrine falcon

Pachyramphus aglaiae Rose-throated becard

Parula pitiayumi Tropical parula

Buteo albicaudatus White-tailed hawk

Mycteria americana Wood stork

Buteo albonotatus Zone-tailed hawk

Fish Cycleptus elongates Blue sucker

Cyprinella proserpina Proserpine shiner

Hybognathus amarus Rio Grande silvery minnow

Etheostoma graham Rio Grande darter

Reptiles and 

Amphibians Crotaphytus reticulatus Reticulate collared lizard

Drymarchon melanurus 

erebennus Texas indigo snake

Leptodeira septentrionalis 

septentrionalis Northern cat-eyed snake

Gopherus berlandieri Texas tortoise

Phrynosoma cornutum Texas horned lizard

Notophthalmus meridionalis Black-spotted newt

Rhinophrynus dorsalis Mexican burrowing toad

Smilisca baudinii Mexican treefrog

Hypopachus variolosus Sheep frog

Siren sp. 1 South Texas siren

Leptodactylus fragilis White-lipped frog

Mussels Potamilus metnecktayi Salina mucket

Truncilla cognata Mexican fawnsfoot mussel

Quadrula mitchelli False spike mussel

73
Table 3-7. Species of Concern in Maverick, Starr, Webb, and Zapata 

Counties (TPWD, 2012)

Category Scientific Name Common Name

Mammals Myotis velifer Cave myotis bat

Myotis yumanensis Yuma myotis bat

Choeronycteris mexicana Mexican long-tongued bat

Geomys personatus davisi Davis pocket gopher

Spilogale putorius interrupta Plains spotted skunk

Mormoops megalophylla Ghost-faced bat

Birds Icterus cucullatus cucullatus Mexican hooded oriole

Charadrius montanus Mountain plover

Falco peregrinus tundrius Arctic peregrine falcon

Icterus graduacauda audubonii Audubon’s oriole

Icterus cucullatus sennetti Sennett's hooded oriole

Ammodramus bairdii Baird's sparrow

Cyanocorax morio Brown jay

Chondrohierax uncinatus Hook-billed kite

Geothlypis trichas insperata Brownsville common 

yellowthroat

Athene cunicularia hypugaea Western burrowing owl

Fish Notropis jemezanus Rio Grande shiner

Moxostoma austrinum Mexican redhorse

Ictalurus sp. 1 Chihuahua catfish

Ictalurus lupus Headwater catfish

Reptiles and 

Amphibians

Holbrookia lacerata Spot-tailed earless lizard

Insects Cicindela obsoleta neojuvenilis Neojuvenile tiger beetle

Cicindela cazieri Cazier’s tiger beetle

Tetracha affinis angustata Tiger beetle

Plants Asclepias prostrata Prostrate milkweed

Atriplex klebergorum Kleberg saltbush

Cardiospermum dissectum Chihuahua balloon-vine

Houstonia correllii Correll’s bluet

Physostegia correllii Correll’s false dragon-head

Coryphantha macromeris var. 

runyonii

Runyon’s cory cactus

Eriogonum greggii Gregg’s wild-buckwheat

Paronychia maccartii McCart’s whitlow-wort

Coryphantha nickelsiae Nickel’s cory cactus

Manfreda longiflora St. Joseph’s staff

Thelypodiopsis shinnersii Shinners’ rocket

Acleisanthes crassifolia Texas trumpets

Argythamnia argyraea Silvery wild-mercury

74
The ocelot and Gulf Coast jaguarundi are known or believed to occur in 

all four program counties. They hunt for small prey and prefer dense, 

thorny, low brush. The Gulf Coast jaguarundi inhabits similar habitat to 

the ocelot but is more active in the daytime than the ocelot, a nighttime 

hunter (FWS, 2010; FWS, 2012 a). The least tern nests on bare or sparsely 

vegetated sand, shell, and gravel beaches, sandbars, islands, and salt flats 

associated with rivers and reservoirs in Starr, Webb, and Zapata Counties 

(FWS, 2013). In particular, least terns nesting at Falcon Reservoir are near 

the proposed fence location (FWS, 1990). Ashy dogweed occurs on the 

sandy pockets of Maverick-Catarina, Copita-Zapata, and Nueces-Comita 

soils of southern Webb and northern Zapata Counties (TPWD, undated b). 

Johnston’s frankenia tends to occur within openings in the blackbrushdominated brushlands on pockets of highly saline soils, often in 

association with saladillo (Varilla texana), in Starr, Webb, and Zapata 

Counties (TPWD, undated c). Zapata bladderpod and its designated 

critical habitat occur in Starr and Zapata Counties. Zapata bladderpod 

critical habitat refuge tracts (Cuellar, Chapeno, Arroyo Morteros, Las 

Ruinas, Arroyo Ramirez, and Los Negros Creek) are near the proposed 

fence location (FWS, 2000). 

In the United States, star cactus occurs in Starr County (see restoration 

efforts Section F). It grows on sparsely vegetated areas in gravelly, saline 

clays, or loams at low elevations in the Rio Grande Plains (FWS, 2003). 

Walker’s manioc grows in dense stands of native brush or in small 

openings in Starr County. Many of the listed plants could be present in the 

proposed fencing locations (TPWD, undated d). The Texas hornshell is a 

freshwater mussel known to occur in the Rio Grande near Laredo, in 

Webb County and is unlikely to be in areas proposed for fence installation 

(FWS, 2012 b). 

H. Human Health and Safety

Federal agencies must identify and address disproportionately high and 

adverse human health or environmental effects of its proposed programs, 

policies, and activities on minority and low-income populations in the 

United States and its territories and possessions as described in Executive 

Order 12898. Executive Order 13045 encourages similar considerations 

for children. 

1. Environmental 

Justice

75
Colonia is a term used in the southwestern States to describe a subdivision 

where developers divide the land into small lots and offer affordable 

housing to low-income families. These lots are often purchased through a 

contract for a deed with a low down payment and low monthly payments. 

The title for the house is not issued until the final payment is made by the 

homeowner (Anon., 2013 a). Housing in these locations is built by 

residents over time as they can afford materials. Consequently, many 

residences lack connections to sewers or running water, and residents may 

not be able to access water lines because their homes do not meet county 

building codes (Anon., 2013 a). The U.S. Census Bureau reports that up to 

3 percent of households in Maverick, Starr, Webb, and Zapata Counties 

lack complete plumbing, and some lack basic amenities (Census, 2010-

2011). Residents often rely on septic tank systems, but because of 

inadequate drainage and installation combined with elevation and 

topography issues, sewage may overflow (Anon., 2013 a). The proposed 

fence segments are unlikely to alter or address any of these issues because 

the proposed fence construction is not expected to change topography or 

drainage. 

Approximately 400,000 Texans live in colonias, and reportedly 85 percent 

of those residents under 18 were born in the United States (Anon., 2013 a). 

APHIS identified areas where residents in colonias may be impacted by 

the proposed project (Appendix J) and ensured that residents of these local 

colonias were notified of the project and represented at public meetings. 

In Maverick County, fence segments are proposed for construction within 

the El Indio Townsite colonia in El Indio along the irrigation canal and 

near Loma Linda #1 colonia in Rosita North. There are no Maverick 

County schools located near the project area. In Starr County, fence 

segments are proposed near the following schools: Lago Vista, Indio #1, 

Indio #2, La Loma de Falcon, Salineno North, and Los Arrieros colonias 

near Falcon Heights. Three miles south of the proposed fence segments, 

near Roma Creek, four schools are located (Scott Elementary School, 

Barrera Elementary School, Roma Accelerated Learning Academy, and 

Roma Intermediate School). We are proposing fence segments for two 

areas adjacent to the Dolores and Lopena colonias and for two locations 

on either side of the Morales-Sanchez and the San Ygnacio colonias in 

Zapata County. Benavides Elementary School, located approximately 

0.3 miles north of the proposed fence segment, is within the San Ygnacio 

colonia. APHIS considers potentially impacted schools as important 

2. Colonias

76
because of the high likelihood for children to play in areas less than 1 mile 

from fence locations. 

Identification of nearby school areas is important to APHIS to ensure 

access to these institutions and because the fencing will become part of the 

children’s every day environment. As discussed in the previous section, 

only one school is located within 0.5 miles from the proposed fence 

segments (approximately 0.3 miles). The four other identified schools are 

located approximately 3 miles from the proposed fence segments. 

The proposed fence installation in Maverick, Starr, Webb, and Zapata 

Counties would occur where the populations are predominantly of 

Hispanic origin, and more than one quarter of the population has annual 

earnings below the poverty line (Appendix J). Fewer than 4,400 people 

reside within 0.25 miles of the proposed fencing in fewer than 2,000 

housing units. Webb County does not have any residential housing within 

0.25 miles of the proposed fencing (Census, 2010-2011). 

In Webb County, approximately 73,000 residents were born outside of the 

United States, while in Maverick and Starr Counties, each has 

approximately 18,000 residents born outside of the country. Zapata 

County is reported to have slightly more than 3,000 residents born outside 

of the United States. In the last decade, populations in the four counties 

rose 10 to 30 percent. The median age of residents varies from 27 to 

30 years old (Census, 2010-2011). 

In all four counties, more than 85 percent of the households speak a 

language other than English at home, and fewer than 60 percent identify 

themselves as speaking English “very well” (Census, 2010-2011). For this 

reason, APHIS met with NRCS and USDA’s National Institute of Food 

and Agriculture in August and September 2010 to discuss the best 

outreach methods for this area. In addition, the APHIS Administrator sent 

an invitation to the Director of the Colonia Initiatives Program regarding 

public meetings. APHIS provided documents in Spanish as well as 

English prior to and at public meetings and also posted flyers in public 

places near colonias. APHIS also will provide a translated copy of the EIS 

Executive Summary on its website. Based on these efforts, residents of 

these communities are aware of the proposed project.

3. Schools

4. Socioeconomics

77
Fewer than 60 percent of residents in each county are involved with the 

labor force, and fewer than 16 percent of the workforce in each of these 

counties is involved with agriculture, forestry, fishing, hunting, and 

mining (Census, 2010-2011). To the extent that fence construction efforts 

may hire from these local communities, the proposed project may provide 

assistance to local economies primarily in the form of temporary job 

opportunities. 

From 2002 to 2007, the number of farms increased 46 percent in Maverick 

County, 27 percent in Starr County, and by nearly 20 percent in Webb and 

Zapata Counties. The majority of farms in Maverick County are small (10-

49 acres) while farms in the other three counties tend to be mid-sized (50-

499 acres) or large (more than 1,000 acres). While the market value of 

products sold in Zapata County was not disclosed, the majority of 

farmland in the other counties is used as pasture, with livestock sales 

accounting for 80 percent or more of the market value of products sold 

(NASS, 2007). 

I. Cultural, Historic, and Visual Resources

Federal agencies providing funds, or otherwise providing assistance or 

approval for agency actions, must account for the effects of the impact on 

historic properties included in, or eligible for inclusion in, the National 

Register of Historic Places (16 U.S.C. § 470). The National Register is the 

basic inventory for historic resources in the United States maintained by 

the Secretary of the Interior. Any property listed in, or eligible for listing 

in, the National Register of Historic Places is considered historic (36 CFR 

§§ 63, 800). 

APHIS identified 27 registered Historic Places in the four counties 

(Appendix K). Specifically, there are two listed Historic Places in 

Maverick County, nine in Starr County, ten in Webb County, and six in 

Zapata County. APHIS compared these locations to those listed in the 

Atlas database on the Texas Historical Commission web site 

(http://www.thc.state.tx.us/). We placed all locations of historic resources 

on a Geographic Information System map and overlaid it with the 

proposed locations for game fencing. 

The historic sites within Maverick County are within city limits and more 

than 10 miles from areas proposed for game fencing. The nearest historic 

78
sites within Starr County are approximately 2 miles from areas proposed 

for game fencing. All of the Historic Places in Starr County are near the 

U.S./Mexican border. They all appear to be located within township or 

city areas and are not located near proposed CFTEP fencing areas. The 

historic sites within Webb County are more than 20 miles from areas 

proposed for game fencing. Most of the historic sites within Zapata 

County are more than 2 miles from areas proposed for game fencing. 

Three historic sites are located less than 1 mile from the proposed fencing: 

Corralitos Ranch (0.4 miles from fence); Trevino-Uribe Rancho (0.6 miles 

from fence); San Ygnacio Historic District (0.6 miles from fence). 

Using the NAGPRA Online Databases (NPS, 2013), APHIS determined 

that there is only one tribe, the Tonkawa Tribe of Oklahoma, with former 

land in the area of the proposed fence. 

The visual resources for rural border counties in Texas are the rangeland 

and pastures this proposed project intends to secure. These counties are of 

minimal recreational or scenic interest except for areas directly along the 

Rio Grande River. For each National Historic Site identified within 1mile 

of the proposed game fencing, the visual resources also include any 

buildings, street patterns and road characteristics, in addition to view 

corridors and vistas. 

APHIS recognizes that while the proposed fencing may be visible from 

some vantages, mere visibility does not constitute a significant adverse 

impact. The significance of the visibility depends on context and intensityrelated factors, which include the rangeland as a scenic resource within the 

view of the proposed fencing, general characteristics of the surrounding 

landscape, and the extent to which the visibility of the proposed fencing

interferes with the public’s enjoyment or appreciation of these resources. 

A significant adverse visual impact occurs if the visibility of the game 

fencing significantly detracts from the public’s enjoyment of a resource or 

if the game fence’s design, distance, intervening topography and 

vegetation, and context exceed the minimal impact to be effective. 

The proposed game fence is expected to be visible from highways or roads 

that parallel fence sections. The fence design will not block the view to the 

other side of the fence because it will be constructed of a strong tensile 

woven wire, with 4-inch by 3-inch openings (figure 2-1). The proposed 

game fencing is designed to prevent animals from jumping over it. In 

79
areas where current wire fencing is too short to stop these animals, the 

proposed installation of game fence would add 3 to 4 feet of additional 

height to the wire fence. The game fencing will not be continuous in areas 

where townships are located, and people would not see fencing in those 

areas. Non-property owners are not likely to see the proposed fencing 

unless they are travelling on a road that parallels the game fencing, or 

when travelling among townships along the U.S./Mexican border near the 

fencing. Fencing would not be placed on river banks due to the 

unpredictable flooding of the Rio Grande. Hikers would only notice game 

fencing if they are on a trail that parallels the fence line. 

In general, various types of fencing already are maintained in areas where 

APHIS proposes game fencing for tick control. Low fencing is used to 

maintain livestock, prevent wildlife access, or for aesthetic purposes. In 

addition, wildlife access to properties is prevented by high fencing in areas 

of Maverick County. 

80
IV. Environmental Consequences

This chapter discusses the direct and indirect effects associated with the 

No Action and Proposed Action alternatives. Each section within the 

chapter is divided into descriptions of program compliance with statutes 

and Executive Orders, when relevant, followed by a description of the 

potential impacts from each alternative. The No Action alternative 

includes current program operations to help prevent the spread of ticks and 

potential exposure of cattle to babesiosis without the aid of game fencing. 

The Proposed Action alternative includes installation of game fencing on 

privately owned property with landowner consent. Relevant issues 

evaluated under each alternative include: 

• Land Characteristics

• Climate

• Air Quality

• Water Quality

• Livestock Health

• Vegetation

• Wildlife

• Human Health and Safety

• Cultural, Historic, and Visual Resources 

• Cumulative Impacts

A. Land Characteristics

Maverick, Starr, Webb, and Zapata Counties lie within an area designated 

by NRCS as the Rio Grande Plain. Soils are fine- to course-textured, well 

drained, and have limited soil moisture for use by vegetation during the 

growing season (McNab and Avers, 1994). Soils range from alkaline to 

slightly acidic clays and clay loams. The predominant soils in the fence 

areas are deep clay loams and sandy clay loam over clay.

APHIS obtained soil surveys for Maverick, Starr, Webb, and Zapata 

Counties (Molina and Guerra, 2011; Sanders and Gabriel, 1985; Stevens 

and Arriaga, 1977; Thompson et al., 1972) and consolidated the 

information into table 4-1. This table shows the type and location of the 

soil series identified by Federal surveyors. Areas with similar soils are 

grouped and labeled as a soil series because their comparable origins and 

81
chemical and physical properties cause the soils to perform similarly under 

various land uses (NRCS, 1999). Table 4-1 indicates in a general manner 

which physical attributes of a soil series may present potential 

environmental hazards. 

If the No Action Alternative were implemented, surface soil disturbance 

would continue to occur during patrols for stray or smuggled livestock and 

ongoing maintenance of existing fences. This could result in minor 

erosion; however, this alternative will not influence flooding potential of 

the soils, nor will flooding impact the outcome of the alternative if it is 

selected. 

If the Proposed Action Alternative is selected, surface soil disturbance and 

soil loss would be limited to the corridor where the fence would be 

installed. Sites with soil loss to a depth of 3 feet could cause long-term 

environmental impacts; however, erosion to this extent is not expected. 

Therefore, we believe the impacts of building the fence would be 

transient. 

Table 4-1 focuses on those soil attributes that are most likely to increase 

the risk of environmental impact, should the fence be installed in certain 

types of soil. Physical attributes of greatest concern in the project area 

include erosion and shrink-swell potential (the extent to which soil shrinks 

or swells with changes in soil moisture content). Flooding also has the 

potential to occur; however, flooding will not be impacted by the fencing 

due to its permeable nature. Additionally, soil compaction will be confined 

to the fence line, so the fence is unlikely to influence the potential for 

flooding. The table also estimates a hazard level as compared to 

undisturbed soils. In the project area, most of the proposed fence segments 

are located in previously disturbed soils along U.S. Highway 83. 

Other physical attributes, such soil layering, clay/sand/loam content, 

water, and organic matter content, are not expected to be affected longterm by project activities; environmental impacts are expected to be 

minimal due to implementation of proposed mitigations discussed below. 

1. No Action 

Alternative

2. Proposed 

Action 

Alternative

82
Table 4-1. Soil series identified in Maverick (M), Starr (S), Webb (W), and Zapata (Z) Counties 

(Molina and Guerra, 2011; Sanders and Gabriel, 1985; Stevens and Arriaga, 1977; 

Thompson et al., 1972 )

Series Location Project-related attributes1 Hazard level2 

Aguilares W, Z Erosion Moderate

Arroyada W Erosion; Shrink-swell potential Moderate to Severe

Brennan S, Z Erosion; Flooding; Shrink-swell potential Moderate

Brundage M, W, Z Erosion; Shrink-swell potential Slight to Moderate

Brystal M, W Erosion Slight to Moderate

Camargo S Flooding; Shrink-swell potential Moderate

Catarina M, S, W, Z Erosion; Shrink-swell potential Moderate to Severe

Comitas S, W, Z Erosion Moderate to Severe

Copita M, S, W, Z Erosion Slight to Moderate

Cuevitas W, Z Erosion Slight to Moderate

Dant M Erosion Moderate

Darl M Water Moderate

Delfina W Erosion Slight to Moderate

Delmita S, W, Z Erosion Slight to Severe

Dilley W Erosion Slight to Moderate

Duval W Erosion Slight to Moderate

Elindio M Erosion Slight to Moderate

Escobas Z Erosion Moderate

Falfurrias S, Z Erosion Severe

Garceno S, Z Erosion; Shrink-swell potential Moderate to Severe

Grulla S Flooding; Shrink-swell potential Severe

Hebbronville W, Z Erosion Slight to Severe

Houla Z Erosion; Shrink-swell potential Moderate

Jimenez M, S, W, Z Erosion Slight to Severe

Lagloria M, W, Z Erosion Slight to Moderate

Laredo M, W, Z Erosion; Shrink-swell potential Slight to Moderate

Matamoros S Shrink-swell potential Severe

Mavco M Erosion Moderate

Maverick M, S, W, Z Erosion; Shrink-swell potential Moderate to Severe

McAllen S Shrink-swell potential Slight to Moderate

Mercedes M Erosion Slight

Moglia W, Z Erosion; Shrink-swell potential Moderate to Severe

83
(Table 4-1, continued)

Series Location Project-related attributes1 Hazard level2 

Montell M, S, W, Z Erosion; Shrink-swell potential Moderate to Severe

Monwebb Z Erosion; Shrink-swell potential Moderate to Severe

Nido W, Z Erosion; Shrink-swell potential Low to Moderate

Nido variant W Erosion; Shrink-swell potential Low to Moderate

Nueces W, Z Erosion Slight to Severe

Olmos M Erosion Severe

Palafox W Erosion; Shrink-swell potential Moderate

Pryor M Erosion Slight to Moderate

Quemado M, S, W, Z Erosion Slight to Moderate

Ramadero S Flooding Severe

Randado W, Z Erosion Slight to Moderate

Reynosa M, S Erosion Slight

Rio S Shrink-swell potential Moderate to Severe

Rio Grande M, S, W, Z Erosion; Flooding; Soil blowing Slight to Severe

Sarita S, Z Erosion Severe

Tela W, Z Erosion Slight

Tiocano S Erosion; Flooding; Shrink-swell potential Severe

Tonio Z Erosion Slight to Moderate

Veleno Z Erosion; Shrink-swell potential Moderate

Verick M, W, Z Erosion; Shrink-swell potential Slight to Severe

Viboras W, S, Z Erosion; Shrink-swell potential Slight to Severe

Zalla M, S Erosion; Flooding; Soil blowing Moderate to Severe

Zapata M, S, W, Z Erosion Slight to Severe

1

Soil attributes relevant to the project also may include: erosion; compaction or shrink-swell potential; flooding; acid-alkaline balance; 

salinity; slope and depth; clay/sand/organic matter content; etc. The attributes considered most likely to affect, or be affected by, the 

program activities are considered here. Hazard level estimates are for undisturbed soils. The erosion hazard is always listed, 

regardless of level (slight/moderate/severe). Other hazards are listed only when they can be identified as moderate or severe. This 

table lists some of the physical attributes of 55 soil series in the four counties. 

2

Soil series hazard levels as presented in this table vary depending upon their association with one another and where they were 

observed by the surveyors. An erosion hazard for one soil series may be reported as “slight” in one survey location, and as “severe” 

in another; in those instances the table indicates the range of reported levels. This table provides a condensed overview of a wide 

range of soil attributes and potential hazards and should not be used in determining the final location and construction method for 

the proposed fence installation. Soil hazards and their proper management by landowners and project participants will vary 

depending upon (a) location of a given soil relative to the program area, and (b) other contributing factors such as slope, depth, 

drainage, season of the year, weather events, traffic, etc.

84
We did not include chemical attributes for soils within the four counties in 

table 4-1. The proposed fencepost foundation and fencing materials are 

designed to be inert and to resist rust and corrosion. Therefore, a soil’s 

chemical attributes, such as pH or salinity, are expected to be only 

temporarily affected, resulting in minimal or no environmental impact. 

Potential mitigation measures used to reduce the impact of fence 

installation on soils in Maverick, Starr, Webb, and Zapata Counties 

include language in the APHIS contracts with landowners to encourage 

clearing the smallest amount of vegetation necessary for fence installation 

and staging fence supplies in previously cleared areas so as to not remove 

additional vegetation. Vegetation should be allowed to regenerate in the 

cleared area after fence installation to prevent erosion. 

B. Climate

Climate in South Texas is considered subtropical, with hot temperatures in 

the summer and mild temperatures in the winter. Precipitation averages 

20 inches annually (Bomar, 2008). Based on observations of tick 

populations in areas of Mexico that are already experiencing warming 

cycles (Estrada-Pena, 2001), tick populations that establish themselves in 

the United States are anticipated to fluctuate as the temperature increases 

and precipitation decreases. 

Tick prevalence and range increase with adequate habitat conditions, 

including shrub cover or mesquite, due to microclimate effects of shade 

and humidity (Corson et al., 2001; Teel, 1984). Tick survival is greater in 

areas infested with giant reed (Arundo donax, a woody, non-native 

invasive grass) than in open pastures and closed canopy native forests 

(Racelis et al., 2012). Zones close to optimum habitat conditions that 

experience sudden changes outside of these limits are expected to show 

the highest enzootic (affecting animals of a specific geographic area) 

instability (Estrada-Pena, 2001). 

Tick populations decrease when habitat suitability is poor (Coburn, 2010; 

Estrada-Pena, 2001; Estrada-Pena and Venzal, 2006), temperatures are 

constantly over 77 degrees Fahrenheit (Corson et al., 2004), and there is 

less grazing (Estrada-Pena et al., 2006; Teel et al., 1996). Uncanopied 

buffelgrass (Cenchrus ciliaris syn. Pennisetum ciliare) does not support 

ticks laying eggs (Racelis et al., 2012) and is an inhospitable microclimate 

3. Potential 

Mitigation 

Measures

1. Impacts 

Common to 

Both 

Alternatives

85
for eggs that are laid (Teel, 1984); therefore, reduced tick populations 

would be expected in border areas where there is encroachment by this 

invasive grass. 

Based upon historically available data within APHIS records, there 

appears to be a lag after hurricane events before tick populations rise to 

the level of detection. The frequency of severe weather events (such as 

hurricanes and tornadoes) in South Texas may increase with global 

warming (Pérez de León et al., 2012). Additional rainfall (as occurs with 

hurricanes) is well documented as a trigger for an increase in tick 

populations (Coburn, 2010; Corson et al., 2004; Davey et al., 1991; 

Edney, 1982; Estrada-Pena, 2001; Estrada-Pena et al., 2006; Teel, 1984). 

Additional tick mitigation measures must continue to be developed and 

used commensurate with environmentally induced changes in tick 

populations. 

Under the No Action Alternative, tick populations could become reestablished throughout their original ranges in the United States (Pérez de 

León et al., 2012). Climate change would likely lead to localized effects as 

tick populations quickly responded to open/dry versus closed canopy/ 

moist conditions throughout the range of establishment (Estrada-Pena, 

2001). As climate change occurs, the distribution of favorable vegetation 

is expected to shift north. In the absence of fencing, the distribution of 

ticks capable of infesting this vegetation and infecting livestock would 

shift north because of the unrestricted movement of an increasing 

population of white-tailed deer. This is because the spatial distribution of 

habitats with optimal microclimates interacts with host-landscape behavior 

to disperse and sustain tick populations (Pérez de León et al., 2012). The 

potential expansion of current program actions north would be associated 

with increased greenhouse gas production and effects to climate change 

commensurate with the level of increased control action required for the 

program. Therefore, the No Action Alternative has the potential for greater 

impact on climate change in the long term than the Proposed Action 

Alternative. 

South Texas has rolling-plains vegetation (Aiken, 2005; Davis, 1990), and 

much of the proposed fence would be along highways and right-of-ways 

where vegetation already is controlled; therefore, very few forested areas 

would be affected under this alternative. More tick-favorable 

microclimates near fencing could lead to increased populations (Pérez de 

2. No Action 

Alternative

3. Proposed 

Action 

Alternative

86
León et al., 2012) if the ticks were not precluded and the vegetation was 

not controlled near the fence. Nevertheless, the Proposed Action 

Alternative is not likely to induce rapid, large-scale vegetation changes 

similar to those observed in Africa after fence installation (Boone and 

Hobbs, 2004; Gadd, 2010). This is based on both the prior history of 

fencing in this Texas border area (Bram et al., 2002) and on other 

interactive factors (grazing, fire, and climate change) that are responsible 

for species composition changes in South Texas areas (Grover and 

Musick, 1990). 

Fences are associated with changes in migration patterns and vegetation 

(Boone and Hobbs, 2004; Gadd, 2010), and these changes in turn affect 

the amount of greenhouse gases sequestered in the local flora (Butcher et 

al., undated). If shrubs are allowed to grow near fenced areas (Pérez de 

León et al., 2012), then these fenced areas could become associated with 

increased sequestration of carbon stored in the environment. If the habitat 

shifts to more closed-canopy microclimates near the fence, then the effects 

of climate change on land and resource management activities may 

include a shift to increased hunting in the affected area. 

The presence of a non-electrified fence, by itself, does not directly 

contribute to climate change by emitting greenhouse gases. Despite the 

efficacy of electric fences in reducing movement of deer and other wildlife 

(McAtee, 1939), the direct and indirect effects, as well as monetary costs 

associated with electrified fences (which include ongoing greenhouse gas 

emissions associated with the use of electricity) do not make this a viable 

option. 

The Proposed Action is associated with minimal CO2 emissions into the 

human environment in comparison to the 25,000 metric ton reference 

point suggested by the CEQ (CEQ, 2010). The vast majority of CO2

emissions in the Proposed Action Alternative occur during the production 

of the steel fencing materials. The estimated CO2 emissions for travel 

during maintenance activities for the current fencing could be used as a 

baseline for comparison between the alternatives; however, APHIS 

inspectors only monitor fence integrity as a collateral duty while on other 

travel (2013) and older (existing) fencing is more likely to need increased 

maintenance. 

87
Maintenance needs usually arise from humans cutting or climbing on the 

fence, accidental vehicle penetrations, and animals (feral swine, javelinas, 

or coyotes) digging under the fence. Weather conditions may deteriorate 

the fence over a long period (e.g., more than 15 years) (Messenger, 2013). 

Consequently, vehicle travel for maintenance would be incurred regardless 

of which alternative is chosen, given that existing fencing is older and 

would likely require more maintenance than new fencing. Emissions 

associated with installation travel are negligible in comparison to the CO2

emissions involved in steel production. To the extent that the Proposed 

Action Alternative could use more efficiently produced steel, APHIS 

could achieve an off-site reduction in greenhouse gas emissions. 

C. Air Quality

Maverick, Starr, Webb, and Zapata Counties have better air quality than 

many of the other major urban areas around the State (Combs, 2008), with 

major sources of air pollution coming from highway vehicular traffic, 

petroleum production, and agriculture (TCPS, 1995). 

Air emissions from stationary and mobile sources are regulated as a way 

to protect and improve air quality (42 U.S.C. §§ 7401 et seq.). In a given 

region or area, air quality is measured by the concentration of pollutants in 

the atmosphere. Air quality also is influenced by surface topography and 

prevailing meteorological conditions. Under the CAA, the EPA 

established National Ambient Air Quality Standards (40 CFR 50)) to 

protect public health and welfare and to regulate emissions of hazardous 

air pollutants (EPA, 2012).

If the No Action Alternative were implemented, vehicular traffic, land 

uses, and ranching would remain the same, and there would be no change 

to air quality in South Texas. The portions of existing fence in the project 

area would continue to have minor impacts to air quality caused by some 

fence maintenance activities producing vehicle emissions. 

The proposed CFTEP fence would be constructed near highways and 

roads where major sources of air pollution in these regions are highway 

vehicular traffic and agriculture (FHWA, 2007). Criteria pollutants 

(pollutants for which maximum allowable emission levels and 

concentrations are enforced by State agencies) will be produced by 

construction vehicles during fence installation and maintenance activities. 

3. Proposed 

Action 

Alternative

1. Clean Air 

Act

2. No Action 

Alternative

88
Effects will be localized and minimal compared to vehicular activities in 

the area and will have little or no impact on air quality in South Texas. 

Fence construction will result in some soil and debris disturbance that may 

become airborne during installation. The airborne particles should quickly 

settle and not have any significant or long-term impact. 

Greenhouse gas emissions associated with the Proposed Action 

Alternative arise from the production of fencing materials, fencing 

installation (including travel to/from construction sites), and subsequent 

travel associated with fence maintenance. Calculations based on CO2

emissions can only be estimated. These estimates include: (a) the 

manufacturing efficiency in the country of the steel’s origin, (b) carbon 

emissions associated with the zinc coating and painting processes, 

(c) carbon emissions associated with installation of concrete footers, 

(d) topography at each site of installation, (e) the extent of partial 

construction at sites where prior fencing is being extended or land is 

already cleared of vegetation, and (f) the number of agreements in the 

project, which affects the total length of fencing in the project. Similarly, 

the distance to supply repositories will directly impact the greenhouse gas

emissions associated with installation and maintenance, even though we 

project fewer than 70 miles of fencing to be installed. APHIS cannot 

predict the frequency of fencing repairs, as well as the fuel efficiency of 

vehicles used to deliver fencing materials or perform fence maintenance 

(Messenger, 2013). For these reasons, APHIS acknowledges this 

alternative would be associated with small, off-site greenhouse gas 

emissions that can be estimated only with low confidence.6 This 

alternative does not exhibit on-site, continuous, or large greenhouse gas 

emissions over 25,000 metric tons (a reference point for quantitative 

analysis suggested by CEQ) (CEQ, 2010). 

6 Assume: (1) the galvanized steel is produced with CO2 emissions of 1.9 tons of CO2 per metric 

tonne (mt) of steel (Kundak et al., 2009), (2) all 70 miles is fenced, (3) a 330-foot length of fixed knot 

woven mesh fencing weighs 400 pounds (203 mt steel over 70 miles), (4) each T-post weighs 14 

pounds, and posts are installed every 20 feet (117 mt steel over 70 miles), and (5) other fence 

components (H-braces, ends, angles, and clips) total 80 mt of steel over the 70 miles. At 1.9 tons of 

CO2 emitted per mt of steel produced (400 mt of steel)(1.9 mt of CO2 / 1 mt steel), we estimate 760 mt 

of CO2 emissions associated with the production of fencing materials. Also assume: (1) each 

construction vehicle emits 350 g CO2 per passenger mile (Bradley, 2007), and (2) construction travel 

requires 10 vehicles to make 10 trips along all 70 miles (7,000 miles). When converted to mt, this is 

an estimated 2.45 mt CO2 emission associated with construction travel. These assumptions lead to a

total estimate of 763 mt of greenhouse gas emissions for the fence alternative. 

89

 
Impacts can be avoided by clearing land and construction activities in 

damp soil and avoiding construction activities during windy days. The 

APHIS agreements with landowners can encourage such practices. 

D. Water Quality

The proposed CFTEP fence is located within the central portion of the Rio 

Grande watershed. The major water bodies of this watershed include the 

Rio Grande bordering the west or southwest of all four counties, the Main 

Canal in Maverick County, Falcon Dam on the west border of Starr and 

Zapata Counties, and Falcon Reservoir and its three arms that extend into 

Zapata County (Arroyo Burro, Arroyo del Tigre Grande, and Arroyo del 

Tigre Chiquito). Minor water bodies include streams and arroyos 

(Appendix I). 

The CWA (33 U.S.C. §§ 1251 et seq.), regulates surface water quality 

standards and the discharge of pollutants into U.S. waters. The CWA 

regulates the placement of dredged or fill material into waters of the 

United States (40 CFR § 232). The proposed project will not cross any 

bodies of water and therefore will not require Section 404 permitting. 

The National Pollutant Discharge Elimination System (40 CFR §§ 122-

503) regulates pollutant discharge into surface waters of the United States, 

and TCEQ administers this System (30 TAC §§ 305.533 - 305.541). The 

Texas Pollutant Discharge Elimination System (§§ 305.533, 305.541) 

improves the quality of rivers, lakes, and streams by regulating pollution 

released from multiple sources (TCEQ, 2013). APHIS would be required 

to comply with requirements outlined by the Texas Pollutant Discharge 

Elimination System. 

Federal agencies must avoid, to the extent practicable, impacts associated 

with the occupancy and modification of floodplains as directed by EO 

11988. The proposed project would cross 100-year floodplains in 

12 locations (table 3-3; Appendix I). No special fence construction 

methods would be needed in the floodplain areas. The extreme 

permeability of the CFTEP proposed fence will allow high levels of water 

to penetrate and will be secure enough that it is not likely to dislodge 

during floods. We do not anticipate that the proposed CFTEP fence will 

alter the floodplains due to the permeability of the fence and the absence 

of any substantial ground removal or alterations. 

4. Potential 

Mitigation 

Measures

1. Clean 

Water Act

2. Texas 

Pollutant 

Discharge 

Elimination 

System

3. Executive 

Order 11988 

– Floodplain 

Management

90
Federal agencies must consider alternatives to wetland sites to minimize 

destruction, loss, or degradation of wetlands as directed by EO 11990. We 

identified two areas meeting the requirements to be called wetlands (40 

CFR §§ 122-503). These aquatic sites are associated with Arroyo Molletes 

and Arroyo Ranchito, which are located one mile north of the city of 

Zapata, just west of U.S. Highway 83. At Arroyo Molletes, the total area 

of wetland in the proposed fence area is 0.1 acre. This wetland is located 

west of U.S. Highway 83 in the right-of-way. At Arroyo Ranchito, 

approximately 0.14 acre of wetland is located west of U.S. Highway 83 in 

the right-of-way (FHWA, 2007). 

The proposed fence construction will result in some vegetation clearing 

and some soil disturbance that could result in an increase in erosion into 

wetlands and some disturbance of wetlands due to land clearing for the 

fence and vehicle traffic. The impacts are expected to be extremely minor 

and not result in permanent impacts. Furthermore, our agreements with 

landowners will encourage efforts to avoid or minimize impacts to these 

wetlands and to use silt curtains and vegetation restoration to prevent any 

soil runoff into wetland areas. We do not anticipate that the Proposed 

Action will impact wetlands, therefore mitigations are not needed. This 

final determination will be made by the U.S. Army Corps of Engineers. 

If the No Action Alternative were implemented, there would not be any 

impacts to 27 jurisdictional waters associated with the project area or to 

water quality, and permits from the U.S. Army Corps of Engineers would 

not be required. Current land uses, ranching, and activities (including 

urban development) would continue uninterrupted, incrementally affecting 

water quality. The portions of existing fence in the project area would 

continue to have minor impacts to water quality caused by some fence 

maintenance activities. These maintenance activities may result in some 

erosion into waterways due to foot traffic, maintenance, and vehicular 

traffic. 

If the Proposed Action Alternative is selected, there is the potential to 

impact 27 jurisdictional waters associated with the project area, including 

two wetlands. However, the proposed game fence will not be installed 

across any U.S. waterways and will only be installed up to and adjacent to 

the high water mark. Impacts to waterways will be limited to some soil 

disturbance during fence installation that may erode into waterways or 

4. Executive 

Order 11990 

– Protection 

of Wetlands

5. No Action 

Alternative

6. Proposed 

Action 

Alternative

91
wetlands. Similarly, vehicular traffic may also cause some disturbance to 

soil during construction and maintenance. There are no impacts of the 

proposed project on water bodies; therefore, permits are not needed. 

During construction, stormwater runoff would flow into natural drainage 

areas before reaching the Rio Grande. Although portions of the proposed 

fence will be in areas drained by segments of the Rio Grande currently 

recognized as an impaired waterway (Anon., 2011), the project does not 

encroach on the portions of these segments that have water quality 

concerns, and no substantial impacts are anticipated to the ambient water 

quality of the basin segments. This is due to a small area of impervious 

cover in the project area compared to the total area of the watershed. 

We would encourage landowners to avoid or minimize impacts to water 

bodies during fence construction. Indirect effects of the proposed game 

fencing to water resources include increased potential for erosion and 

sedimentation during construction activities and fence maintenance 

activities. Clearing vegetation for the proposed project could increase the 

potential for erosion and sedimentation into nearby local drainages and 

receiving streams. These effects are expected to be temporary and minor 

and would be reduced by the appropriate use of Best Management 

Practices during construction. No long-term water quality impacts are 

expected as a result of the proposed project. 

The proposed project would not alter the U.S.-Mexico border, alter water 

distribution or use between the countries, affect levees or floodways, or 

impact border sanitation or water quality issues. Consequently, there do 

not appear to be any treaty requirements for the United States section of 

the International Boundary and Water Commission (IBWC, 2013) to 

address. Any work proposed within the floodplain and adjacent to the 

main channel of the Rio Grande, including the Falcon Reservoir where it 

forms the international boundary between the United States and Mexico, 

must be submitted to the International Boundary and Water Commission 

for its review and approval. Fence segments are not proposed for Falcon 

Reservoir, so it is unlikely that we will need to take this action. 

Groundwater sources are several miles from the proposed game fence and 

the minor amount of sedimentation and/or ground disturbance resulting 

from construction and maintenance of the fence would have no 

appreciable effect on groundwater resources (George et al., 2011). 

92
Construction of the fence is not expected to impact the amount or quality 

of run-off water into the navigable waterways of the Rio Grande and 

Falcon Reservoirs because the construction area at each site is small, less 

than 5 feet deep, and of short-duration. These parameters suggest that any 

run-off water will not contain substantial particulates, chlorine, or heavy 

metals. Presence of fencing is not expected to impact the amount or 

quality of run-off water into the navigable waterways of the Rio Grande 

and Falcon Reservoirs based on its construction parameters that allow 

water to flow unimpeded through and around fence segments. 

The CFTEP proposed fence construction does not include any activities 

that would significantly increase stormwater runoff. Land clearing during 

construction would be minor, with minimal disturbance anticipated for 

fence maintenance activities. The fence would be located in developed 

areas next to major highways and commercial and residential land parcels. 

No alteration in the ground permeability to stormwater would occur as a 

result of the fence. 

Impacts can be avoided by working closely with the TCEQ and 

encouraging landowners to ensure Best Management Practices during 

fence construction. 

E. Livestock Health

The CFTEP in the United States initially used fences in combination with 

other mitigation measures such as acaricide treatments, pasture vacation, 

and inspection (Anon., 1965; Bram et al., 2002). As mentioned in Chapter 

1, wildlife managers installed an 80-mile, 6-strand, electrified barbed-wire 

fence in Florida and had much success with this tool in combination with 

other mitigation measures. However, the same outcome has not yet 

occurred in Texas because existing fencing is segmented and very few 

sections are considered to be game fencing. Game fencing has proven to 

be an important part of the management strategy to reduce migration of 

tick-infested cattle, and stray and exotic livestock (Anderson et al., 2010). 

This section covers the impacts to livestock health that may result from 

construction of additional fencing to prevent the entry and spread of cattle 

fever ticks into South Texas. While we consider a range of health impacts 

that may be seen in all livestock species, we focus on impacts to ticksusceptible livestock raised in the affected area and discuss the effects to 

7. Potential 

Mitigation 

Measures

93
animal health from both ticks and the diseases they vector. Animal 

diseases not spread by ticks or limited by the installation of fencing will be 

unaffected by the proposed action and are not considered further (e.g., 

spread of diseases such as rabies that can be transmitted by bats or small 

mammals not restricted by the fencing). 

The cattle fever tick life cycle consists of four stages: egg, larva, nymph, 

and adult. Hosts for the larva are usually cattle, but ticks also will 

occasionally infest, horses, mules, deer, sheep, or goats. Cattle fever ticks 

are a one-host tick, meaning that they feed on only one host during their 

life stages (larva, nymph, and adult). A blood-engorged female tick 

detaches from its host and can release 1,000 to 2,000 eggs before dying on 

the ground. For a complete description of the life cycle of cattle fever 

ticks, see Chapter 1 (Purpose and Need) and Chapter 3 (Affected 

Environment). 

USDA defines “livestock” as all farm-raised animals (7 U.S.C. § 

8302(10)). Cattle are the primary tick-susceptible livestock in the 

proposed fence areas. Other tick-susceptible livestock raised in the 

affected area include horses (Equus spp.), sheep (Ovis spp.), angora goats 

(Capra aegagrus hircus), and swine (Sus scrofa). 

“Exotic livestock,” grass-eating or plant-eating, single-hooved or clovenhooved mammals that are not indigenous to the State and are ungulates, 

are also raised in Texas. These include animals from the swine, horse, 

tapir, rhinoceros, elephant, deer, and antelope families (6 Texas 

Agriculture Code § 161.001(4)). Also, landowners who wish to own, 

breed, sell, or restock properties with privately owned white-tailed deer 

(Odocoileus virginianus) can obtain a Deer Breeder Permit. Under this 

permit, a breeder actually owns the animals and can propagate, sell, or 

purchase deer similar to other forms of livestock. Deer held by a permitted 

deer breeder belong to the individual; however, if released from the 

Breeder Facility, the deer enters into the State’s population and becomes 

property of the State of Texas. 

White-tailed deer can be infested by ticks but function as diluting hosts for 

the disease babesiosis because the protozoan parasites do not reproduce to 

become an infective stage within the deer (Pérez de León et al., 2012). In 

addition, cattle fever ticks have been identified on other exotic livestock 

including nilgai (Boselaphus tragocamelus), aoudad sheep (Ammotragus 

94
lervia), elk (Cervus canadensis), fallow deer (Dama dama), axis deer 

(Cervus axis Erxleben), red deer (Cervus elaphus), and American bison 

(Bison spp.) in South Texas (Duhaime, 2009; Pérez de León et al., 2012). 

Since cattle are the predominant livestock species in Maverick, Starr, 

Webb, and Zapata Counties, the impacts analysis is primarily focused on 

impacts to cattle health with consideration given to potential impacts to 

livestock health from deer and other wildlife. 

The World Organization for Animal Health defines a disease vector as an 

insect or any living carrier that transports an infectious agent from an 

infected individual to a susceptible individual or its food or immediate 

surroundings (OIE, 2010). Cattle fever ticks can reduce livestock 

productivity and well-being as obligate blood-feeding parasites when 

present in relatively high numbers; they can indirectly harm hosts even 

when present in relatively low numbers by serving as vectors of the 

infectious agents that cause bovine babesiosis (Babesia bovis, and B. 

bigemina) and anaplasmosis (Anaplasma marginale) (Aubry and Geale, 

2011; Pérez de León et al., 2012). Babesiosis generally is characterized 

by extensive intravascular hemolysis (rupture of red blood cells) leading to 

depression, anemia, icterus (jaundice), hemoglobinuria (presence in the 

urine of hemoglobin from ruptured red blood cells), and neurological signs 

(Barros and Fighera, 2008). 

In general, tick infestation in cattle without the protozoan-causing disease 

triggers anemia from blood loss. This anemia is accompanied by 

decreased appetite and weight loss. Each engorging tick can cause more 

than one gram in weight loss (the engorging durations varied between 

28 and 810 days) (Jonsson, 2006). In cattle, tick feeding can reduce the 

weight of a 1,000-pound steer by 200 pounds in a year (APHIS, 2010) and 

eventually result in death (APHIS, 2010; Jonsson, 2006).

Cattle with the acute form of babesiosis develop high temperatures (106 ̊F 

or higher; the normal rectal temperature range for a cow is 98 to 102.8 °F) 

(Lew-Tabor, 2011). Usually, the cattle die 3 to 4 days after the high fever 

develops. Prior to death, cattle will stand abnormally with their heads 

lowered and backs arched. These cattle exhibit a loss of appetite combined 

with constipation followed by diarrhea, and they produce less milk. 

Hemoglobinuria, or “red water,” is common (Barros and Fighera, 2008; 

CFSPH, 2008; APHIS, 2010). 

1. Disease 

Transmission 

between Feral 

or Wild 

Animals and 

Livestock

95
Cattle affected with the chronic form of babesiosis develop a mild fever, 

generally stop eating and chewing their cud, and develop anemia and 

rapidly lose weight. This chronic form may last for many weeks, after 

which most animals gradually recover. Infected cattle are likely to suffer 

from relapses in the first several months after resolution of clinical signs. 

Infected cattle may also experience increased susceptibility to other 

diseases such as bovine tuberculosis (TB) and may display nervous 

behaviors called “tick poverty” (also known as “tick worry”). The growth 

of chronically infected immature cattle becomes stunted, and these 

animals are typically weak. Surviving cattle that are infected continue to 

suffer from anemia associated with the continual loss of blood due to 

babesiosis as well as ongoing tick feeding. In the summer, the disease 

incubation period (the time from when an animal is exposed until it first 

shows symptoms) can be as short as 10 to 15 days after the larvae (seed 

ticks) begin to feed on the animal. During the winter months, the 

incubation period may take as long as 90 days (APHIS, 2010; Ellenberger, 

1940).

Cattle fever ticks also are capable of carrying and transmitting the 

infectious agent that causes bovine anaplasmosis (Aubry and Geale, 

2011). This disease causes progressive anemia due to extravascular 

(outside of blood vessels) destruction of infected and uninfected red blood 

cells. In the late stages, acutely infected animals become weak and milk 

production declines. They experience a lack of appetite, loss of 

coordination, breathlessness when exerted, and a rapid pulse (Lew-Tabor, 

2011). 

Other livestock in the proposed fencing areas, such as horses, also can 

carry ticks and tick-borne diseases. Horses are not only a host for cattle 

fever ticks causing babesiosis, but also are a host for numerous other tick 

vectors that can cause the tick-borne disease called equine piroplasmosis. 

This disease is caused by B. caballi or B. (Theileria) equi (Barros and 

Fighera, 2008). Stray horses from Mexico can spread southern cattle ticks, 

American dog ticks (Dermacentor variabilis), and cayenne ticks

(Amblyomma cajennense and A. imitator) transmitting equine 

piroplasmosis (Barros and Fighera, 2008). 

Additional livestock diseases reported in Texas that are not tick-borne but 

can be transmitted through infected stray livestock or exotic livestock such 

96
as feral swine include Johne’s disease, brucellosis, and pseudorabies. 

Johne’s disease, which affects cattle, sheep, and goats, is caused by the 

bacterium Mycobacterium paratuberculosis. If stray livestock from 

Mexico are infected with this disease, they can transmit the disease to 

healthy cattle, sheep, and goats. Swine brucellosis and pseudorabies are 

diseases that affect pigs and are caused by the bacteria Brucella suis, and 

the virus Suid herpesvirus, respectively. Domestic swine in the United 

States are currently free of swine brucellosis and pseudorabies. However, 

stray or feral swine can transmit these diseases to domestic swine, thereby 

reintroducing diseases that have been eradicated in U.S. livestock. In 

addition, feral swine could spread other foreign animal diseases, such as 

classical swine fever or foot-and-mouth disease, to domestic swine or 

other susceptible animals if these diseases were to enter the United States 

(TAHC, 2012). 

As previously mentioned, deer are a vehicle for tick propagation and 

relocation by serving as hosts for completion of the tick life cycle. Deer 

also can be a vector for other diseases such as TB (MDNR, 2011-2013). 

This disease was once the most prevalent infectious disease of cattle and 

swine in the United States. Currently, Texas is recognized as free of 

bovine TB (TAHC, 2013). 

The remaining subsections examine aspects of ticks and diseases that 

APHIS expects to vary in intensity depending on the alternative chosen. 

Under the No Action Alternative, the free-ranging movement of stray 

livestock (e.g., cattle) and deer across non-fenced or ineffectively fenced 

properties would continue. This unrestricted movement was reflected in an 

observed increase in the number of cattle fever ticks and cattle fever tick 

infestations in South Texas in recent years (Duhaime, 2009; Pound et al., 

2010). The number of infested premises increased eight-fold in 6 years 

(FY 2003 to FY 2009) (Duhaime, 2009). By FY 2011, 108 new 

infestations were reported both within and outside of the Permanent Tick 

Quarantine Zone. There were 17 new infestations in the Temporary 

Preventative Quarantine Areas along Highway 83–one in Webb County 

and 16 in Zapata County. In FY 2011, almost one-quarter of the new 

infestations were found in white-tailed deer (Duhaime, 2011). 

Movement of tick-infested, white-tailed deer from Mexico across the Rio 

Grande is often a suspect source of infestations in Texas because 

2. No Action 

Alternative

97
increasing numbers of cattle fever ticks have been identified on whitetailed deer and both cattle fever ticks and babesiosis are endemic to 

Mexico. In endemic areas, animals tend to become infected when young, 

do not become as ill, and recover to become immune (Barros and Fighera, 

2008). Furthermore, many of these ticks are acaricide-resistant strains 

(Pérez de León et al., 2012). Acaricide-resistant ticks are increasingly 

detected around the quarantine buffer zone along the Mexican border 

(Duhaime, 2011; Pérez de León et al., 2012) because of the large numbers 

of stray cattle and white-tailed deer that may carry acaricide-resistant tick 

strains as they cross the Rio Grande for grazing purposes or in search of 

water during drought conditions (Pérez de León et al., 2012). 

Introductions of tick vectors (as carriers of pathogens) may lead to 

devastating and widespread babesiosis outbreaks in the U.S. cattle 

population (Pérez de León et al., 2012). The presence of a vector 

population would rapidly spread any introductions of the disease because 

vector-borne diseases require both a competent vector and the pathogenic 

organism. When Babesia-bearing animals enter into an area where the tick 

vector already is present, susceptible hosts that subsequently graze in the 

infested pastureland are likely to become diseased. This entry of Babesiainfested ticks into areas that were previously tick-free would be 

problematic for immunologically naïve cattle because these cattle have not 

been previously exposed to the protozoan pathogen (Angus, 1996). Naïve 

cattle become sicker and are more likely to become clinically affected 

leading to death than cattle in areas where babesiosis is endemic. Even if 

these cattle survive the infection, they become less productive throughout 

their lives and do not grow and fatten normally (Barros and Fighera, 2008; 

CFSPH, 2008). 

In the absence of effective fencing, producers and government agencies 

rely on other measures to control ticks, such as acaricide treatment and 

vacation of pastures (Pérez de León et al., 2012; Pound et al., 2010). Cattle 

may experience increased physical stress and fatigue from being gathered 

for the bi-weekly process of acaricide treatments. Increasing use of 

acaricides is likely to lead to development of more acaricide-resistant 

strains of ticks that could eventually spread northward. 

Under the Proposed Action Alternative, the free-ranging movement of 

stray or exotic livestock across fenced properties would be restricted by 

the game fencing. Few mammals are capable of jumping over an 8-foot 

3. Proposed 

Action 

Alternative

98
high fence. Therefore, APHIS expects that the proposed fencing will 

restrict the movement of ticks beyond the permanent tick quarantine line 

into the free area of Texas. APHIS also anticipates that preventing 

movement of tick-carrying animals may reduce other diseases in U.S. 

cattle and other livestock. For example, the proposed fence may assist in 

preventing movement of feral swine that can carry brucellosis and 

pseudorabies. Under this alternative, animal health is likely to be 

improved because fewer infested and infected animals (stray/exotic 

livestock and wildlife reservoir populations) would come in contact with 

U.S. livestock or be able to carry ticks and the diseases they may transmit 

(Angus, 1996; Gadd, 2010; Pérez de León et al., 2010; Taylor and Martin, 

1987). 

In comparison to the No Action Alternative, we expect that the Proposed 

Action Alternative will result in a decreased need for acaricide treatments 

because of the lower tick burdens north of the installed fencing. Decreased 

frequency of acaricide treatments may reduce the rate at which acaricideresistant tick strains develop. Fewer acaricide treatments also should 

decrease the physical stress on livestock associated with being gathered 

for acaricide treatment. 

We expect that preventing the movement of ticks beyond the Permanent 

Tick Quarantine Zone will greatly reduce the likelihood of tick 

introduction into northern Texas Concentrated Animal Feeding Operations 

(CAFOs). Impacts from uncontrolled tick populations in CAFOs could 

become severe because of the close proximity of the animals in these 

confined herds. 

Under the Proposed Action Alternative, ticks are less likely to become 

established in Texas and subsequently disseminated throughout the 

country. If controlled by an integrated management strategy that includes 

the use of fencing, ticks and tick-borne diseases located in Mexico would 

be less likely to negatively impact U.S. agriculture. 

Since the proposed alternative benefits livestock and reduces potential 

impacts from ticks and tick-vectored diseases, we do not recommend any 

additional mitigation measures pertaining to livestock health.

4. Potential 

Mitigation 

Measures

99
F. Vegetation

Maverick, Starr, Webb, and Zapata Counties are located within a distinct 

ecoregion known as the South Texas Brush Country. It is an arid to semiarid region with drought-tolerant vegetation. Native species are reliant on 

soil moisture made available by seasonal rains, occurring primarily during 

the early summer and fall months (Jahrsdoerfer and Leslie, 1988; Taylor et 

al., 1997). 

Human activity has had a tremendous impact on the landscape (McMahan 

et al., 1984), via brush control and grazing practices associated with cattle 

ranching. This region has experienced a 23 percent increase in woody 

cover since 1941 (Council, 1994). Previously restricted to thickets, upland 

areas, major drainages, and river bottoms, shrub species are now prevalent 

across the landscape. In addition to human activity, periodic droughts have 

aided the gradual migration of brush species into open grassland. These 

periodic droughts are predicted to increase in frequency and duration as 

the effects of climate change become more prevalent (Karl and Knight, 

1998). 

Federal agencies are directed by EO 13112 to prevent the introduction or 

spread of non-native invasive species and to control populations of nonnative invasive species to minimize economic, ecological, and human 

health impacts. Federal agencies cannot authorize, fund, or carry out 

actions that they believe are likely to cause or promote the introduction or 

spread of non-native invasive species in the United States unless they 

analyze and consider all reasonable measures to minimize risk of harm. 

Cooperation with State, local, and other Federal agencies for the 

management and control of noxious weeds and non-native invasive plant 

species is required under the PPA (7 U.S.C. §§ 7701-7786). 

The National Invasive Species Council ensures that Federal efforts to 

prevent and control invasive species are coordinated, effective, and 

efficient (EO 13112). Texas defines “invasive species” as those, “not 

native to an ecosystem and whose introduction to the ecosystem causes or 

has been demonstrated to cause economic harm, environmental harm, or 

harm to human health” (Texas Government Code § 776.001 (b)). To help 

prevent the spread of noxious weeds and non-native invasive plant species 

within the State, the TISCC works with the Texas Invasive Plant and Pest 

Council (TIPPC), an advisory council regarding policy and management 

1. Noxious Weed 

and Invasive 

Species

Concerns

100
of invasive species, to coordinate activities and programs with Federal and 

State agencies. 

The TISCC and the TIPPC advise Federal and State agencies about 

practices that prevent the inadvertent movement of invasive plant or 

animal species by vehicles or in materials such as soil, mulch, gravel, or 

sod that are transferred from one site to another. For the Proposed Action, 

any materials excavated during fence installation would remain on site, 

preventing the spread of weed seeds or invertebrates in this manner. 

Requirements of the project are such that animal species would not be 

inadvertently introduced or spread during the installation process; 

therefore, we focus on the potential spread of noxious weeds and nonnative invasive plant species associated with the Proposed Action. 

Until an approved national list of invasive plant species is defined by the 

National Invasive Species Council, the FHWA issued guidance on 

August 10, 1999 encouraging each State’s Department of Transportation 

to use the State’s noxious and invasive plant species list in defining the 

invasive plants that must be considered under EO 13112 and as part of the 

NEPA analysis for a proposed project. A total of 26 invasive plant species 

occur within the area proposed for fence construction (TIPPC, 2011) (see 

table 3-5). Of these species, we consider saltcedar (Tamarix spp.) and 

giant reed (Arundo donax) (4 TAC § 19.300(a)). 

Saltcedar (Tamarix spp.) 

Tamarix species are spreading shrubs or small trees, 5 to 20 feet tall, with 

numerous slender branches and small, alternate, scale-like leaves. Plants 

tend to grow densely and form thickets along streambeds (arroyos) that 

flood seasonally. Seeds generally require soils that are seasonally saturated 

at the surface with extended periods of soil saturation for establishment. 

Saltcedar (tamarisk) also can spread by roots or submerged stems and is 

adaptable and tolerant of a wide variety of environmental conditions 

(Baum, 1978). 

Saltcedar disrupts the structure and stability of native plant communities 

and degrades native wildlife habitat by outcompeting and replacing native 

plant species. Saltcedar is a fire-adapted species and has long tap roots that 

can obtain water from deep reservoirs (Flanders et al., 2006). The species 

consumes water more rapidly than native vegetation; on average, saltcedar 

101
stands consume 3,000 to 4,600 cubic meters of water per hectare per year, 

nearly twice the total annual precipitation for the region (Flanders et al., 

2006). 

Along with limiting the groundwater supply, saltcedar stands draw salts up 

to the surface from deep in the soil. Once secreted by the leaves of the 

plant, salt deposits give rise to increasingly saline soils that are not 

tolerated by many native plant species (Zavaleta, 2000). Although it 

provides some shelter for wildlife, the foliage and flowers of saltcedar 

provide little food value for native wildlife species that depend on 

nutrient-rich, native plant resources (Flanders et al., 2006). Saltcedar fails 

to harbor plant-eating insects that insectivorous birds, reptiles, and 

mammals can eat, provides poor structural or microclimate diversity, and 

is too small in stature or limb size to support large birds such as raptors 

(Zavaleta, 2000). 

Giant reed (Arundo donax L.)

Arundo donax L., or giant reed, is a vigorous, invasive perennial grass 

capable of growing up to 25 feet high with stems up to 1.5 inches in 

diameter. Giant reed develops a deep, fibrous root system and large 

creeping rhizomes. The plant reproduces quickly via vegetative 

reproduction, a form of asexual reproduction in plants. This allows giant 

reed to out-compete native vegetation and dramatically alter ecological 

processes (Bell, 1997). Any disturbance that breaks up the shoots or 

rhizomes (horizontal underground stem that is capable of producing shoots 

and roots), including the use of bulldozers and plows, has the potential to 

spread this plant to new areas (Boland, 2006). Pieces of shoot remain 

viable up to 123 days after separation from the parent plant, while 

rhizomes can sprout up to 132 days after separation. Giant reed grows best 

near water, though its occurrence in a variety of habitats suggests the 

invasive grass can adapt to drier conditions. A recent study found stands 

growing as far away as one half mile from the Rio Grande in South Texas 

(Yang et al., 2011). 

Through its deep root system, giant reed consumes more water than native 

vegetation and is capable of growing more than 2 feet per week during 

warm months (Iverson, 1994). This rate of growth and water consumption 

displaces native vegetation. During winter dry periods, the dense, massive 

stands increase the risk of wildfire. The presence of giant reed has a 

102
negative effect on bird, reptile, and mammal species by reducing 

invertebrate diversity (Herrera and Dudley, 2003) and suitable habitat. 

Noxious and invasive species may spread either by seed, root, or plant 

parts. They are naturally dispersed by a variety of means including wind, 

water, and wildlife. However, dispersal can be assisted by human activity 

through the use of vehicles and construction equipment. Vehicle traffic is 

a major contributor to weeds invading a new area, as seeds and plant parts 

can become embedded in tire treads and mud carried on a vehicle from an 

infested area (Sheley et al., 1996). Seeds and plant parts also can get 

caught in construction equipment or embedded in soil and dust that 

collects on construction equipment. After the construction equipment has 

been transported to another site, the weed seeds and plant parts can be 

washed off the equipment as a result of precipitation and introduce the 

invasive plant species into new or restored areas. In addition, fence 

maintenance activities that require the use of vehicles or construction 

equipment, such as repairing holes or fence posts, may also be a means of 

transporting and spreading non-native invasive plant species. 

Potential direct impacts associated with the introduction or spread of 

noxious weeds and non-native invasive plant species includes the 

establishment of infestation areas and the loss or degradation of native 

vegetation communities, which could provide a niche for noxious weeds 

and invasive plant species to flourish. Potential indirect impacts may 

include loss of wildlife habitat and rangeland for grazing livestock due to 

diminished native plant communities, as well as soil erosion due to the 

establishment of non-native plant species. In addition, the spread of 

noxious weeds and non-native invasive plant species may increase the 

susceptibility of fire on the landscape (Sands et al., 2009). 

Within the fence installation areas, however, saltcedar and giant reed 

habitat do not have any suitable habitat. Therefore, mitigation measures 

will reflect general activities that minimize the risk of inadvertent 

dispersal of non-native species. 

Federal agencies must ensure that their actions are not likely to jeopardize 

the continued existence of threatened or endangered species or result in the 

destruction or adverse modification of critical habitat (16 U.S.C. 1531-

1544; 50 CFR § 402). APHIS considered the impacts of the proposed 

action on federally listed threatened and endangered species and 

3. Endangered 

Species Act

2. Potential 

Environmental 

Consequences 

103
designated critical habitat, and is currently engaged in formal consultation 

with the FWS because of potential effects on listed species in the action 

area. Fence construction activities will not occur until we have completed 

the Section 7 consultation 50 CFR § 402). 

Ashy dogweed, Johnston’s frankenia, Zapata bladderpod, Star cactus, and 

Walker’s manioc

Adverse effects on federally listed plants in the action area could occur 

from fence construction and maintenance activities, such as land clearing, 

herbicide use, and trampling. In addition, seeds of invasive weeds that 

may compete with listed plants could be carried on construction 

equipment to cleared sites. 

APHIS will conduct surveys to determine the location of listed plant 

species in the project area. This information will be used to make 

determinations of effects of the Proposed Action on listed plants, and to 

avoid those effects either by realigning the proposed fence or by relocating 

listed plants. The Proposed Action will not adversely modify the 

designated critical habitat for the Zapata bladderpod because fence 

construction will not occur there. APHIS is developing other conservation 

measures, such as requiring contractors to clean equipment between sites, 

to minimize effects on federally listed plants in the project area. 

The vegetative cover will continue to mature and produce seeds and 

rhizomes if the No Action Alternative is chosen. Reproduction and 

moderate spread of existing non-native invasive plant populations by 

natural means of dispersal (i.e., wind, water, and wildlife) can be 

anticipated. In addition, occasional maintenance of existing fencing will 

likely require the use of vehicles, which are a major contributor to weeds 

invading new areas. Woody plants are expected to continue their increase 

in density as a result of climate change. 

The Proposed Action Alternative would require removal of vegetation in 

the construction area, which will subsequently cause direct impacts to the 

microclimate in the immediate vicinity of the proposed game fencing. The 

canopies of woody plants modify the microclimate beneath and around 

them by intercepting precipitation and shading the ground, both of which 

influence the amount of soil moisture available to plants (Breshears et al., 

1998). The removal of woody plant canopy is likely to result in higher soil 

temperatures, which in turn decreases the amount of surface soil moisture 

4. No Action 

Alternative

5. Proposed 

Action 

Alternative

104
available to plants. These changes to the microhabitat are likely to 

indirectly impact invertebrate, reptile, and mammal species; however, the 

impact to most species is expected to be short term and limited in area as 

vegetation will regrow upon completion of fence installation. Impacts to 

threatened and endangered species and species of concern will be 

discussed in a separate section following completion of the Section 7 

formal consultation with FWS. 

Native plants are critical to the overall resilience and stability of the South 

Texas Brush Country ecoregion and help maintain greater levels of species 

biodiversity (Karr and Roth, 1971; MacArthur and MacArthur, 1961; 

Maywald and Doan-Crider, 2008; Roth, 1976; Willson, 1974). 

Additionally, arid environments are better able to sustain critical 

ecosystem services when they contain a greater variety of plants (Schulze 

and Mooney, 1994). Land that is subject to disturbance, however, favors 

the establishment of non-native invasive species. The establishment of 

these plant species tends to degrade ecosystem productivity and reduce 

biodiversity by out-competing native plant species (Mullin et al., 2000; 

Sands et al., 2009). Non-native grass and shrub species, such as saltcedar, 

buffelgrass, and giant reed can have negative impacts on both plant and 

animal communities by decreasing the availability and quality of species’ 

habitat and food sources (Herrera and Dudley, 2003; Hoyt et al., 2006; 

Sands et al., 2009). In addition, the spread of noxious weeds and nonnative invasive plant species may increase the susceptibility of the 

landscape to fire (Sands et al., 2009). 

Within South Texas, the establishment of several non-native invasive 

species is a concern (table 3-5). These plant species may reproduce either 

by seed, root, or plant parts. They are naturally dispersed by a variety of 

natural means but can also be assisted by human activity through the use 

of vehicles, construction equipment, and materials (per EO 13112). Within 

the fence installation areas, however, saltcedar and giant reed do not have 

any suitable habitat. Therefore, mitigation measures pertaining to nonnative vegetation will reflect general activities that minimize the risk of 

their inadvertent dispersal. 

APHIS will conduct surveys to determine the location of listed plant 

species in the project area. This information will be used to make 

determinations of effects of the Proposed Action on listed plants, and to 

avoid those effects either by relocating segments of the proposed fence or 

by relocating listed plants. The Proposed Action will not adversely modify 

6. Potential 

Mitigation 

Measures 

105
the designated critical habitat for the Zapata bladderpod because fence 

construction will not occur there. APHIS is developing other mitigation 

measures, such as requiring contractors to clean equipment between sites, 

to minimize effects on federally listed plants in the project area. 

To reduce direct and indirect impacts of the Proposed Action on native 

vegetation, APHIS agreements with landowners would specify that the 

amount of vegetation removed for fence installation will be no more than 

10 feet on either side of the proposed fence line (20 foot-wide strips). 

Private landowners will be responsible for clearing new vegetation growth 

along the fence after installation. FWS will provide additional mitigation 

measures to reduce impacts to threatened and endangered species and 

species of concern in the proposed project area. 

To reduce the potential for spread of non-native invasive weeds species 

during construction activities, agreements should specify that equipment 

used at a site will be visually inspected prior to removal from the worksite. 

If the visual inspection finds seeds, roots, or plant parts on the equipment, 

then the equipment will be cleaned using a backpack hand sprayer or 

pressure washer to the greatest extent practicable prior to leaving the site. 

G. Wildlife

Maverick, Starr, Webb, and Zapata Counties are located in the South 

Texas Wildlife Management Area and the South Texas Brush Country 

ecoregion. This area is noted for its cattle industry and diverse wildlife. 

Grassland has been converted to shrublands in South Texas (Pérez de 

León et al., 2012) due in part to the increase in hunting in these areas 

(Pérez de León et al., 2010) as well as for the agriculture and energy 

industries. Bram et al. (2002) report that the progressive conversion of the 

grassland savanna of South Texas and adjacent areas of Mexico to 

shrublands provides a habitat more favorable to the survival of 

nonparasitic life stages of cattle fever ticks. This conversion of land for 

agriculture, commercial, and residential uses increases habitat 

fragmentation (small discontinuous parcels of vegetation) and decreases 

the availability of wildlife corridors. Wildlife corridors are linked parcels 

of land that allow wildlife to travel from one location to another to find 

food, water, and shelter, and they also ensure genetic variability within a 

wildlife population (FWS, 2012 c). 

106
Federal law prohibits an individual to pursue, hunt, take, capture, kill, 

attempt to take, capture or kill, possess, offer for sale, sell, offer to 

purchase, purchase, deliver for shipment, ship, cause to be shipped, deliver 

for transportation, transport, cause to be transported, carry, or cause to be 

carried by any means whatever, receive for shipment, transportation or 

carriage, or export, at any time, or in any manner, any migratory bird or 

any part, nest, or egg of any such bird (16 U.S.C. §§ 703-712; 50 CFR § 

21). 

Texas occurs within the Central Flyway, a bird migration route that is 

composed of the States of Montana, Wyoming, Colorado, New Mexico, 

Texas, Oklahoma, Kansas, Nebraska, South Dakota, and North Dakota, 

and the Canadian provinces of Alberta, Saskatchewan, and the Northwest 

Territories. Many of the migratory bird species of the Central Flyway 

winter in Central and South America. Some migrate across the Western 

Hemisphere to the Arctic Circle, and others migrate to South America 

(NAS, 2013). Birds in this flyway include the American oystercatcher, 

black skimmer, brown pelican, greater sage-grouse, least tern, lesser 

prairie chicken, piping plover, reddish egret, redhead, red knot, ruddy 

turnstone, sanderling, sandhill crane, whooping crane, and Wilson’s plover 

(NAS, 2013). Birds that migrate along this route depend on stopover 

habitat, such as native prairie and wetland areas, along the flyway.

Removal of vegetation during the nesting season of migratory birds could 

result in incidental take of active bird nests, eggs, or hatchlings by 

physical removal or by disturbance from noise of fence construction 

activities. 

Federal agencies taking actions with a measurable negative effect on 

migratory bird populations are directed by EO 13186 to develop and 

implement a Memorandum of Understanding with the FWS that promotes 

the conservation of migratory bird populations. On August 2, 2012, 

APHIS and FWS signed a Memorandum of Understanding to facilitate the 

implementation of this Executive Order. 

The BGEPA (16 U.S.C. § 668) prohibits the take of bald or golden eagles 

unless permitted by FWS. The term “take” is defined as “pursue, shoot, 

shoot at, poison, wound, kill, capture, trap, collect, destroy, molest, or 

disturb” (50 CFR § 22.3). Disturb means to agitate or bother to a degree 

that causes . . . injury . . . a decrease in its productivity . . . or nest 

1. Migratory Bird 

Treaty Act

2. Executive Order 

13186 – 

Responsibilities 

of Agencies to 

Protect Migratory 

Birds

3. Bald and 

Golden Eagle 

Protection Act

107
abandonment, by substantially interfering with normal breeding, feeding, 

or sheltering behavior (§ 22.3). 

Bald eagle breeding populations occur primarily in the eastern half of 

Texas and along coastal counties from Rockport to Houston (TPWD, 

undated e). Nonbreeding or wintering populations are located primarily in 

the Panhandle, Central, and East Texas, although they may be present in 

areas of suitable habitat throughout the State (TPWD, undated e). Golden 

eagles are rare to locally uncommon in their range in West Texas 

(Lockwood and Freeman, 2004). Golden eagle nests are usually placed at 

higher elevations in remote areas on cliffs, in trees, or structures (Tweit, 

2007). Therefore, neither bald nor golden eagle nests are likely to be 

present near fence construction areas. 

If a bald eagle nest were discovered in the vicinity of a fence construction 

site, APHIS would contact the FWS in Clear Lake, Texas and implement 

recommendations for avoiding disturbance at nest sites as provided in the 

National Bald Eagle Management Guidelines (FWS, 2007). These 

guidelines include a 330- to 660-foot buffer from an active nest, 

depending on the visibility and level of activity near the nest. 

Federal agencies must ensure their actions are not likely to jeopardize the 

continued existence of threatened or endangered species or result in the 

destruction or adverse modification of critical habitat (16 U.S.C. §§ 1531-

1544; 50 CFR § 402). APHIS considered the impacts of the proposed 

action on federally listed threatened and endangered species and 

designated critical habitat, and is currently engaged in formal consultation 

with the FWS because of potential effects on listed species in the action 

area. Fence construction activities will not occur before this consultation is 

completed.

Ocelot and Gulf Coast Jaguarundi 

Currently in South Texas, there are only two known breeding populations 

of ocelots: one in Laguna Atascosa National Wildlife Refuge in eastern 

Cameron County and one in Willacy County (Haines et al., 2005). The 

number of ocelots is estimated as 38 in Cameron County (Haines et al., 

2005) and seven in Willacy County (FWS, 2010). Gulf Coast jaguarundis 

are not known to occur in Texas at this time (FWS, 2012 a). 

4. Endangered 

Species Act

108
A short-term effect of the proposed action on the ocelot and jaguarundi 

would be related to disturbance from fence construction. Noise and human 

presence from fence construction activities could cause these species to 

avoid areas where construction activity is occurring. Because the ocelot is 

active at night, APHIS expects disturbance effects on this species to be 

minimal because construction activities would occur only in the daytime. 

In a study of the impacts of seismic oil exploration on ocelots in the 

Amazon, no changes in ocelot movements were detected from this activity 

(Kolowski and Alonso, 2010). Although the jaguarundi is active in the 

daytime and human activities can adversely affect it, no jaguarundis are 

known to occur in Texas at this time (FWS, 2012 a); thus, disturbance of 

jaguarundis from fence construction activities is unlikely. 

Construction of high-game fences may cause long-term loss of 

connectivity of ocelot and jaguarundi populations ranging between 

Mexico and Texas, resulting in genetic isolation. This is especially a 

concern since the South Texas population of ocelot already has reduced 

genetic variability compared to other ocelot populations. The South Texas 

ocelots are found in such small and isolated groups that inbreeding occurs, 

making them increasingly vulnerable to localized extinction. Also, fence 

construction could block wildlife access to freshwater resources. In Africa, 

fences have contributed to the decline of species such as wildebeests, 

giraffes, buffalo, and tsessebes because of blockage of their migratory 

routes, dehydration, and fence entanglement (Mbaiwa and Mbaiwa, 2006; 

Taylor and Martin, 1987). 

Because of these effects, APHIS has determined that the proposed action 

may affect, and is likely to adversely affect the ocelot and the Gulf Coast 

jaguarundi. APHIS is developing conservation measures to benefit or 

promote the recovery of these species as part of the proposed action to 

minimize or compensate for project effects on them. Gaps in the fence at 

water resources, including streams and arroyos, will provide areas of 

crossing for ocelots and jaguarundi and allow them access to freshwater 

resources. In addition, APHIS will survey the entire length of the proposed 

fence location and map areas of potential ocelot and jaguarundi habitat. In 

these areas of appropriate habitat, openings may be placed at the base of 

the fence to allow passage of ocelots and jaguarundi and to ensure that 

impermeable barriers to these species are not created. 

109
Texas hornshell 

Fence construction will have no effect on this freshwater mussel, known to 

occur in the Rio Grande near Laredo, in Webb County. In Webb County, 

the distance of the proposed fence from the Rio Grande ranges from 1.5 to 

4.5 miles. 

Least Tern

Lake Casa Blanca, where least terns breed in Webb County, is 26 miles 

from the fence. However, activities associated with fence construction 

could disturb least terns at Falcon Reservoir in Starr and Zapata Counties. 

Avoidance of construction activities near these counties during the least 

tern breeding season (May through August) would avoid disturbance of 

nesting terns. 

Under the No Action Alternative, wildlife movements would not be 

further limited, and wildlife corridors would not be further decreased. 

White-tailed deer would continue to have access to multiple pastures in 

South Texas, many of which contain cattle. When livestock producers 

round up their cattle for biweekly treatment of cattle with acaricide, whitetailed deer generally move temporarily to an adjacent premises, and then 

most return to the pasture after activities have subsided (Hood and Inglis, 

1974, in Pérez de León et al., 2012). This occurs within the Permanent 

Tick Quarantine Zone, which also increases the likelihood that pastures 

will become re-infested with Babesia-infected ticks. In addition to 

acaricide treatment, ranchers may choose to use pasture vacation as a 

method to eradicate ticks from their property; however, wildlife using 

these areas defeats the purpose of pasture vacation if the wild animals are 

tick-infested. 

Movement of tick-infested, white-tailed deer from Mexico across the Rio 

Grande is a confirmed source of infestations in Texas (Pérez de León et 

al., 2010). Periods of low rainfall contribute to ease of access across the 

Rio Grande. Without game fencing to prevent their interaction with 

livestock, tick-infested, white-tailed deer have the potential to prolong 

quarantines of pastures. 

Under the No Action Alternative, movement of native wildlife, species of 

concern, and threatened and endangered species would continue 

uninhibited. Impacts to bird species would not be changed by the ongoing 

5. No Action 

Alternative

110
CFTEP activities, and birds that have demonstrated evidence of northward 

or eastward extension of their breeding range in the South Texas vicinity 

due to climate change would not be affected by the No Action Alternative.

Wildlife also would be able to freely move as they do now in search of 

food and water should a severe and prolonged drought occur in Mexico 

and South Texas. 

The South Texas Brush Country has one of the greatest concentrations of 

exotic animals in Texas. Free-ranging exotic species reported to have 

infestations of either R. microplus or R. annulatus include nilgai, aoudad 

sheep, wapiti (Cerous Canadensis), red deer, fallow deer, and axis deer 

(Pound et al., 2010; Sheffield et al., 1983). The identification of these 

exotic species and white-tailed deer as tick hosts presents a threat to the 

CFTEP by compromising the success of ongoing eradication efforts. The 

unrestricted movement of these animals between Mexico and South Texas, 

and between the quarantined and tick-free pasture areas, further 

complicates the eradication efforts. 

Livestock benefit from fencing by the reduction of disease transmission 

from wildlife reservoir populations (Angus, 1996; Gadd, 2010; Pérez de 

León et al., 2010; Taylor and Martin, 1987). In contrast, game fencing 

impacts wildlife by hindering access to forage and water resources during 

seasonal migration (Boone and Hobbs, 2004; Gadd, 2010) or could impact 

their ability to exploit resources located within their home range (Urness, 

1976). In Africa, fences exacerbate the effects of climate variability and 

climate change by limiting migration to dry season destinations (Gadd, 

2010; Taylor and Martin, 1987). Similarly, fences in Texas reduced range 

access of native pronghorn antelope by impeding movement, particularly 

to winter-spring ranges (Aiken, 2005). Severe, prolonged drought could 

prompt deer migration from Mexico into the South Texas quarantine zone 

(Davis, 1990; Gonzalez-V. et al., 2010; Pound et al., 2010), particularly as 

deer search for water (Webb et al., 2007). Increased risk for cattle fever 

tick establishment also may arise in additional native deer populations 

maintained for deer hunting (Anon., 2013 b; Davis, 1990; Pérez de León

et al., 2010). 

Other potential impacts to wildlife from game fencing include 

entanglement during crossing attempts. Crossing attempts will be 

minimized by the 8-foot fence height (Perry, undated); however, 

Harrington and Conover (2006) reported that higher mortality rates were 

6. Proposed 

Action 

Alternative

111
associated with woven wire fences with one strand of barbed wire versus 

woven wire fences with no strands of barbed wire or two strands of barbed 

wire. The proposed game fencing would be woven-wire; however, it 

would not include any strands of barbed wire, thereby reducing the 

potential to entangle ungulates during crossing attempts. 

There have been some reports of predators using fences to catch prey. For 

example, along the Trans-Canada Highway, coyotes learned to run 

bighorn sheep into the fencing because the fencing blocked their escape 

corridor (Gibeau and Heuer, 1996). In addition, sheep may have been 

unable to clearly see the fencing due to poor depth perception (Schoenian, 

2011). Deer also are reported to have poor depth perception; however, the 

use of flagging on top of the fencing will make the fence more visible to 

deer (Perry, undated). 

Fences could fail under increased migration attempts (Aiken, 2005; Falk et 

al., 1978; Gadd, 2010; Pérez de León et al., 2010), leading to an increase 

in exposure of U.S. livestock to cattle fever ticks. Feral swine also can 

breach livestock fences (Pérez de León et al., 2012). Wildlife is less likely 

to break through game fencing if gaps in the fence are provided, which 

would occur with the installation of this fencing. Fencing will not cross 

roads, arroyos, or other bodies of water, providing periodic opportunities 

for wildlife movements. Openings at the bottom of the fences also will be 

provided to allow for unimpeded movement of threatened and endangered 

species while maintaining a separation between potentially tick-infested 

ungulates and U.S. livestock. 

Free movement of small to medium-sized mammals (such as American 

badger, desert cottontail, and western spotted skunk) and rodents (such as 

the Mexican ground squirrel, desert shrew, and southern plains woodrat) 

in the proposed fencing areas are unlikely to be impacted because of their 

size respective to the holes in the fence, small natural gaps underneath the 

fence as a result of variations in the landscape, and/or their characteristic 

behaviors. Larger mammals such as coyotes, foxes, and dogs may be able 

to move through the proposed openings in the fence. No published studies 

were located that indicate these animals are hosts for cattle fever ticks. 

Birds have the potential to be impacted by the proposed game fencing. 

Ground-dwelling birds such as the wild turkey (Meleagris gallopavo) and 

bobwhite quail (Colinus virginianus) may be impacted by the loss of 

112
connectivity due to reduced ground-cover vegetation after fence 

installation (Stromberg, 1990). Populations of rodents and some bird 

species may be impacted by increased hunting from predatory birds that 

use the game fencing as a perching location (Burger et al., 1994; Suhonen 

et al., 1994). Birds also have the potential to collide with fences (Baines 

and Summers, 1997). 

Monitoring of unintended harm to wildlife species as a result of the 

proposed game fencing could occur during inspections of fencing by 

livestock producers. Mitigation measures could be implemented, if 

necessary, to prevent further harm of these species. Flagging could be 

placed on the top of fencing by landowners to serve as a warning to 

wildlife in the area, and openings will be provided so that threatened and 

endangered species are allowed freedom of movement within their home 

ranges and migration corridors. 

The following measures would be specified in APHIS agreements with 

landowners to avoid impacts to migratory birds:

• Avoid vegetation removal and use of loud equipment (e.g., 

bulldozer, chipper, chain saw) for fence construction during the 

nesting season (March 15-August 15). 

• If vegetation removal or loud equipment use is necessary during 

the nesting season, a nest survey will first be conducted by a 

qualified surveyor to ensure that no nests containing eggs or birds 

that have not yet fledged will be destroyed or disturbed. 

• If a nest containing eggs or unfledged birds is on a branch or other 

vegetation that must be removed, APHIS will obtain a permit to 

move the nest to a licensed wildlife rehabilitator or else wait until 

the birds have fledged to remove the vegetation. 

H. Human Health and Safety 

Cattle fever ticks are damaging ectoparasites (parasites that live on the 

skin) that cause reduced cattle productivity (Pelzel, 2005) and transmit 

protozoan parasites that cause tick fever (Radunz, 2008), which can be 

fatal when genes for immunity are not present in the animals (White et al., 

2003). Humans are not hosts of these species of ticks (Barros and Fighera, 

2008); however, humans can serve as hosts to a wide variety of other ticks 

that carry diseases. 

7. Potential 

Mitigation 

Measures

113
Both project alternatives incorporate acaricide use, inspection, and patrol 

activities that impact humans as they perform these activities. The No 

Action Alternative will impact humans across the United States by 

allowing unrestricted tick entry and dissemination to occur with 

concurrent increased risks to human health. The Proposed Action 

Alternative will impact construction workers, residents, landowners and 

also has potential impacts on children and hunters. We address both the 

general human health impacts along with special considerations for 

residents of colonias. Because of the proposed fence locations near 

colonias, APHIS is committed to reaching out wherever possible to 

address the needs of this segment of the population. 

Federal agencies identify and assess environmental health and safety risks 

that may disproportionately affect children as a result of agency actions as 

directed by EO 13045. We discuss an assessment of the risks associated

with this project below. 

Federal agencies must identify and address any “. . . disproportionately 

high and adverse human health or environmental effects of its programs, 

policies, and activities on minority populations and low-income 

populations . . .” (EO 12898). 

APHIS has considered whether project impacts occurring in minority and 

low-income populations appreciably exceed or are likely to appreciably 

exceed those on the general public, and whether there will be an impact on 

the natural or physical environment that significantly and adversely affects 

an environmental justice population. These impacts are discussed below. 

Both alternatives in this EIS include a series of eradication activities 

(Angus, 1996) designed to continue the tick-free status in the United 

States. Program activities likely to affect humans include: (a) inspection 

of livestock at selected South Texas markets originating from the 

Permanent Tick Quarantine Zone, (b) patrols for stray or smuggled 

livestock in the Permanent Tick Quarantine Zone along the Rio Grande, 

and (c) inspection and pesticide treatment of tick-host livestock (mostly 

cattle and horses) on quarantined premises. Hunters who harvest animals 

from the counties in the quarantine zone are required to take precautions in 

the handling and transport of hides and carcasses. Specifically, the hides 

of harvested animals from cattle fever tick-infested or exposed premises 

1. Executive Order 

13045 – 

Protection of 

Children from 

Environmental 

Health Risks and 

Safety Risks

2. Executive Order 

12898 – Federal 

Actions to 

Address 

Environmental 

Justice in Minority 

Populations and 

Low-income 

Populations

3. Impacts 

Common to 

Both 

Alternatives

114
must be left behind until they are inspected, treated, and the hunter is 

issued a permit to move the hide (4 TAC § 41.7(b)). 

Although the literature does not show that cattle fever ticks present a 

health threat to humans, people can become infected by protozoan 

parasites and get tick fever. Diseases induced by B. microti, B. divergens, 

and B. bovis are reported in immune-compromised humans. For example, 

the tick-borne rodent parasite B. microti is recognized to cause human 

disease (Barros and Fighera, 2008). Other ticks can transmit human 

diseases--most notably is the transmission of Lyme’s disease (caused by 

the bacteria Borrelia burgdorferi), which is vectored by deer ticks (Ixodes 

scapularis). For these reasons, tick control on animals is important for 

human health. 

The impacts common to both alternatives include baseline health impacts 

related to ticks and potential exposure to acaricide residues. The extent to 

which activities occur is likely to differ under each alternative and is 

separately discussed. 

Human populations in the vicinity of the proposed fence areas include 

nearby residents, hunters, cattle ranchers, and CFTEP employees. 

Residents include people living in colonias and children. These population 

groups may be exposed to ticks under both alternatives; however, the 

extent of the exposure to each group is expected to vary. Hunters are likely 

to be exposed to ticks during the hunting seasons. Residents and ranchers 

are highly unlikely to be exposed to ticks during the course of their normal 

activities. In contrast, children are at increased risk for tick exposure due 

to their outdoor play. 

The exposure to acaricide residues is highly unlikely for residents, hunters, 

and cattle ranchers because acaricide is only used during pesticide 

treatment and access to treatment areas is restricted to authorized 

personnel. CFTEP employees’ exposure to ticks is likely while patrolling 

the border and/or conducting animal inspections, but the exposure is not 

daily. Significant exposure to acaricide for CFTEP employees is unlikely 

because they are trained personnel who wear proper personal protection 

equipment during treatment. The post-application exposure for CFTEP 

employees or ranchers contacting treated animals is minimal because the 

product label does not permit contact with treated livestock immediately 

after application. 

115
The magnitude of effects from program activities on humans is anticipated 

to be greater under the No Action Alternative due to greater tick 

distribution with the lack of new fencing. Some humans in the following 

groups may experience the following beneficial effects of the No Action 

Alternative:

• Cattle ranchers may benefit from the lack of disturbances to their 

property and by not experiencing stress associated with coping 

with change. 

• Residents and hunters may benefit from unrestricted access to 

unfenced areas. 

• Employees may experience additional job security based on the 

need for increased inspections. 

In the absence of the fence, health impacts from increased exposure to 

ticks are expected to rise. Residents and hunters will have increased 

exposure to ticks, increasing their potential exposure to tick-borne 

diseases. The continued increase of tick outbreaks in the tick-free 

quarantine zone would require more personnel time and effort to check 

cattle for ticks and treat cattle affected by the ticks. Adverse effects to 

CFTEP employees are expected to arise from performing more inspections 

and treatments (whenever a premise is under quarantine, pesticide 

applications will be performed every 7 to 14 days), with an increased risk 

of exposure to ticks and potential incidental exposure to acaricide and 

tick-borne diseases. The livelihood and income of local cattle ranchers 

will negatively be impacted, creating stress and reducing their well-being. 

These additional efforts would result in more costs to cattle producers and 

animal health agencies, based on U.S. cattle industry history and 

experiences in other countries (Angus, 1996). 

Under the Proposed Action Alternative, fencing is expected to reduce 

reliance on the existing tick control methodologies by adding another 

control measure. Fencing is a passive structural control measure against 

tick movement, so it is non-invasive to humans. There is not likely to be 

any ongoing, obvious impact on the general public because game fencing 

would not obstruct public or private access roads or driveways or be 

installed through township areas or across water resources, including 

streams and arroyos. 

4. No Action 

Alternative

5. Proposed 

Action 

Alternative

116
Relatively few people would be affected by construction because the 

fencing would be installed on fewer than 70 miles and in sparsely 

populated rural areas. Webb County lacks any nearby population, while 

Starr and Zapata Counties have an estimated combined 1,903 households 

within 0.25 mile of the planned fence locations (Census, 2010-2011). 

Construction workers, rural private landowners, and residents would be 

among the most impacted individuals. Other casual passersby are not 

likely to be affected by construction activities. 

Construction hazards are likely to include limited exposure to noise and 

dust, particularly during installation of concrete footers, from equipment 

and weed control activities if mower or “weed eaters” are used. While 

there may be some noise increase during installation and maintenance, it is 

expected to be infrequent, intermittent, and relatively low. We expect any 

temporary construction debris and dust to be minimal, short-term, and in 

limited locations, with limited negative effects to air, drinking water, and 

consumable vegetation (e.g., crops) nearby. Therefore, these exposures 

would be minimal both in time and duration. There is a minor safety 

concern arising from general construction hazards to employees during 

installation, but this is not an ongoing or continuous physical hazard after 

construction is complete. 

APHIS anticipates that landowners would opt for gates and/or overpasses 

to accommodate the need for human access across fenced areas if 

necessary. APHIS expects that landowners, hunters, utility companies, and 

emergency personnel or equipment that need to traverse the fence would 

access these facilities. 

As a result of adding fencing on their property, there may be a 

socioeconomic impact to landowners if their property taxes increase due to 

perceived added value because of the fence. Also, cattle ranchers may 

experience fence maintenance concerns because the integrity of the fence 

is essential for effectiveness. 

Fewer than 2,000 people reside within one-tenth of a mile of the proposed 

fencing in fewer than 600 units. In addition, we identified one school 

within 0.3 miles of the proposed fence segment. It appears the border 

locations appropriate for effective fencing would disproportionately affect 

nearby colonias populations in comparison to the rest of the nation. People 

living in the colonias are hoping to benefit from temporary construction 

117
jobs. The lure of jobs/economic resources being spent in those areas, when 

combined with the continued assurance of high-quality cheap meat and 

animal products and an added health benefit (created by any reduction in 

exposure to ticks and tick-borne diseases), can reduce any potential 

negative effects. Access to water in the El Indio Townsite is through the 

city water supply, so disproportionate effects to these colonia residents is 

less likely to occur.

The increased potential for tick exposure by children during play cannot 

be addressed by restricting their movement. Yet children would be less 

susceptible to traffic accidents because the fence could serve as a barrier to 

them accessing the roadway. The primary benefit to children in the 

vicinity of the proposed fence is from reduced risk of exposure to zoonotic 

diseases carried by stray animals that are precluded from entry into areas 

by the fence. 

The lack of loose wire ends projecting from the fence reduces the 

likelihood of children injuring themselves while playing near the fence. 

While children may be able to climb the fence more easily than an adult 

because of their small size/ weight, each wire’s weight-bearing capacity is 

low. As a result, climbing attempts by young children appear more likely 

to bend or break wires before the child is likely to fall from a dangerous 

height. 

APHIS planned the fence design to reduce the likelihood that people 

would feel “fenced in” even when near the fence. These psychological 

aspects are enhanced by the fence not being solid, lacking dangerous top 

elements (like barbed wire or angled projections), and not being 

electrified. The psychological adaptation associated with needing to “see 

through” the proposed type of fence is expected to be temporary and 

something that people are likely to ignore after a while. 

Beneficial effects associated with the fencing are expected to include: 

(a) reduced tick spread and disease transmission, (b) excluded livestock 

and wildlife reduces the human health risk of other pests and/or diseases, 

(c) more productive animal husbandry, and (d) reduced costs of meat and 

animal products to U.S. human populations. Hunters in areas with game 

fencing are likely to take tick-free, healthier deer. Residents and hunters 

are likely to have less potential for exposure to ticks, while cattle ranchers 

may also experience reassurance from seeing the fencing, and reduced 

118
concerns regarding cattle security. The large reduction in incidental 

acaricide exposure is likely to benefit workers who conduct cattle 

treatments. 

APHIS expects limited impacts from the noise and dust generated during 

the installation of the proposed fences near Benavides Elementary School 

in Zapata County, despite the location of the fences being close to the 

school. To the greatest extent possible, APHIS will ask landowners to 

avoid fence installation activities during school hours. By implementing 

the identified mitigation measures, there would be no short- or long-term 

impacts on the health and safety of children. 

Any concerns regarding the safety of construction workers with respect to 

construction equipment, dust, and noise will be mitigated through the use 

of personal protective equipment in accordance with applicable safety and 

health regulations (29 CFR §§ 1910 et seq.). To the greatest extent 

possible, APHIS will seek to have contractors implement the general 

construction practice of periodically spraying water to control dust during 

installation. 

If the proposed alternative is adopted, APHIS will actively discuss with 

contracting landowners their options for including gates and/or overpasses 

to accommodate human access so that access points are convenient and 

visible from a distance. 

I. Cultural, Historic, and Visual Resources

This proposed Federal action seeks to avoid, minimize, and mitigate 

potential negative impacts to cultural and historic resources as part of 

APHIS’ compliance with the NHPA and ARPA (16 U.S.C. § 470), and 

NEPA (42 U.S.C. §§ 4321-4347). This would primarily occur by selecting 

game fence materials that minimally impact the environment, both during 

construction and afterward. 

APHIS originally contacted the County Historical Commission Chairs in 

Maverick, Starr, and Zapata Counties in 2009 regarding the proposed 

Federal action. Additional locations were added to the project, and the 

County Historical Commission Chairs in Webb and Zapata Counties were 

contacted in 2013 (Appendix K). The area of potential effect includes all 

areas where game fence segments exist, will be modified, or added within 

6. Potential 

Mitigation 

Measures

119
Maverick, Starr, Webb, and Zapata Counties. The potential effects are 

already realized in areas where high (8-foot) game fencing now exists, and 

are not considered further. This section considers the potential effects 

from the addition of high game fencing to new areas and the increase in 

height where low (4-foot) game fences already exist. The impacts are 

exclusive to each alternative and will be discussed separately below.

ARPA secures the protection of archaeological resources and sites on 

public and Indian lands and fosters increased cooperation and exchange of 

information among governmental authorities, the professional 

archaeological community, and private individuals (16 U.S.C. §§ 470aamm). ARPA requirements extend only to public and Indian-held lands. 

Consequently, ARPA requirements do not apply to the proposed action of 

APHIS providing funding to private landowners for installation of game 

fencing and is therefore removed from further consideration. 

APHIS will meet requirements in the NAGPRA with respect to Native 

American artifacts (25 U.S.C. § 3301-3013). This section also addresses 

children’s play behaviors as related to EO 13045. 

Existing unmaintained game fence segments are expected to lose 

functionality, deteriorate, and look worse over time. If the No Action 

alternative is chosen, there would not be any inadvertent uncovering or 

disruption of previously unknown or undisturbed historic sites or artifacts, 

and the view along the roadsides would continue in its current condition or 

degrade as roadside fencing deteriorates. 

APHIS expects minor ground disturbance for vegetation removal, 

installation of the game fence supports, and fence maintenance. Additional 

population settlements developing along the areas with fencing are not 

likely because current land use involves highways and privately owned 

property. In all these areas, auditory effects are not likely to be more 

intrusive than infrequent and short-term noises associated with installation 

and maintenance of the game fencing. Visual effects during the proposed 

installation activities would be people seeing a work crew installing the 

fence segments or seeing fencing material staged for installation. 

Conversion of 4-foot-high animal fencing along the highway to an 8-foot 

height would not alter traffic patterns or land use. Based on the careful 

1. Archaeological 

Resources 

Protection Act

2. Native American 

Graves Protection 

and Repatriation 

Act and Executive 

Order 13045

3. No Action 

Alternative

4. Proposed 

Action 

Alternative

120
selection of sites, we do not expect that the addition of high fencing into 

proposed areas would alter traffic patterns or land use. 

The proposed alternative does not create a significant adverse visual 

impact because the game fence’s design, the distance, and the intervening 

topography and vegetation do not exceed the minimal impact to be 

effective. The ability to see through the wire fence mesh means that it does 

not detract from the public’s enjoyment of a resource, such as a roadside 

view or the anticipation associated with seeing a historic site at a distance. 

The fence sections are proposed for installation on privately owned land. 

Within the project area, we will make individual agreements with each 

participating private landowner. Disposition of privately held land is 

controlled by the landowner, who retains control over the extent to which 

the integrity of any historical site is maintained. Through these contracts, 

the agency not only flexibly accommodates landowners’ interest in 

protection of known archeological resources, but also encourages 

landowners to consider how any potential impacts to resources on their 

property could be minimized. While we recognize archeological resources 

may exist on a variety of properties, we have not identified specific 

potential impacts of the game fencing on identified sites within these 

counties because APHIS relies on informed owner consent to minimize 

potential impacts. 

The original consultation with the Texas State Historic Preservation 

Officer (Martin, 2009) found that the area of potential effects at each 

historic site does not extend to proposed fence locations, primarily 

because of the distance from fence to site. For example, short-term 

construction activities are not likely to be seen or heard over one-tenth of a 

mile from a historic site. (We discussed potential long-term impacts of the 

proposed fence and public access issues in the “Human Health and Safety” 

section of this chapter.) 

According to the State Historic Preservation Officer materials available in 

2009, Maverick County had not been surveyed for cultural resources. 

Consequently, county officials recommended a survey by a professional 

archeologist. We did not follow this recommendation at that time because 

APHIS had not determined whether to proceed with the fence proposal. 

Since then, there have not been any additional sites proposed for fencing 

in Maverick County. We are continuing consultations with the County 

5. National 

Historic 

Preservation 

Act 

Consultation

121
Historical Commission Chairs as we identify locations for fencing. Their 

information will be presented to the Texas Historical Commission, and at 

that point, a professional archeologist could be hired if additional 

information is necessary. 

APHIS is waiting for a response from Zapata County representatives, who 

were contacted in 2013, based on our identification of additional sites. 

There were no additional sites identified in Starr County, so their 

representatives were not contacted a second time. Most of the areas in 

Starr and Zapata Counties parallel U.S. Highway 83 and have been 

surveyed by the TXDOT as part of their most recent expansions. Previous 

consultations indicated a Starr County cemetery board was not concerned 

because of the relatively large distance between the cemetery and the 

fence line. To the best of APHIS’ ability to make this determination, all 

roadside monuments are located on the non-fenced side of the road. Webb 

County wasn’t part of the original consultations in 2009, but APHIS did 

contact them in 2013. Their representative did not have any concerns and 

stated that we may proceed with the project as described.

Based on the National Register of Historic Places, APHIS identified 

27 registered places in the four counties, and none of these sites appear to 

be in the line of the proposed fence. In Zapata County, there are three 

historic sites within one mile of the proposed fence line: (1) Corralitos 

Ranch (0.4 miles from fence), (2) Trevino-Uribe Rancho (0.6 miles from 

fence), and (3) San Ygnacio Historic District (0.6 miles from fence). At 

these distances, these sites are not expected to experience any ground 

disturbance or audible impacts during normal fence construction activities. 

It is very unlikely that people will be traveling on foot across private 

property and need to find a fence gap, bridge, or gate to cross the fence 

line from approximately one-half mile away as they travel to/from these 

historic sites. Where a historical site’s location is restricted or not 

identified, general effects are assumed to exist if the location is within 

one-tenth mile of the proposed fencing locations. 

It is likely that short-term visual impacts could occur as people travel 

along the highway to/from a historic site. In this situation, the rangeland 

and pastures are part of the visual resources, along with the buildings, 

street patterns, and road characteristics. The fencing is designed to 

minimally impact these vistas. The visibility of the game fence segments 

122
is not likely to significantly detract from the public’s enjoyment of the 

roadside. 

Based on APHIS review of known historic resources and cultural 

resources for the counties that may be affected by the proposed action, 

these ongoing discussions preliminarily allowed us to determine that 

historic resources would not be impacted from installation or maintenance 

of the game fence. 

APHIS sent a letter of inquiry on August 14, 2009 to the Tonkawa Tribe 

of Oklahoma (Messenger, 2009). On August 20, the Tribe replied that they 

did not have any concerns but would like APHIS to notify them if 

something is inadvertently uncovered during the fence installation process 

(Tonkawa Tribe Business Committee and NAGPRA Representative, 

2009). When we identified additional proposed fence segments, we sent a 

second letter to the Tonkawa Tribe on March 21, 2013. They replied with 

an email on April 8 stating that they stand by their original letter (Myer, 

2013). 

Based on the locations, as well as limited depth and size of fence post 

holes, the proposed alternative is not likely to affect sacred sites and is 

highly unlikely to affect the physical integrity of Native American sites or 

artifacts (under EO 13007 or 25 U.S.C. § 3301-3013). If any fence-related 

ground disturbance uncovers any item of potential cultural significance, 

APHIS’ landowner contractor would follow the contract terms based on 

applicable NAGPRA provisions. 

Identification of colonias showed only one school location (Benavides 

Elementary School, within the San Ygnacio colonia in Zapata County) 

approximately three-tenths of a mile north of the proposed fence segment. 

This distance means children are not likely to see the fence from within a 

classroom, but may see it when travelling to/from school. 

To the extent that children may play near fence segments, the mesh size is 

expected to effectively prohibit most balls from passing through to the 

other side. The mesh is expected to be 3 x 4 inches (”), which means a ball 

or other toy must have a radius of 1.5” to easily pass through the mesh, but 

a radius of more than 2” is likely to rebound or become stuck [ 2π(1.5)= 

9.4 inch circumference]. Rebounded and stuck balls are easily retrieved on 

the same side of the fence. 

6. Tribal 

Consultation

7. Protection 

of Children

123
Types of play objects considered are the generally available children’s 

sized balls for: American football (sizes 2-4 exceed 22” circumference), 

soccer (size 3 exceed 23” circumference), basketball (size 5 exceeds 27” 

circumference), and baseballs (generally 9” circumference) (Wikipedia, 

2013; WikiAnswers, 2013). Baseballs could pass through the mesh when 

the throw/hit is well-centered in a mesh square. Children capable of that 

kind of throw are likely to want to retrieve a lost baseball, so agency 

information to residents of colonias could caution parents to warn their 

children not to practice throwing baseballs near the fence because they 

could be hard to retrieve if lost. In comparison, the 13⁄4 to 3” diameters of 

golf balls, tennis balls, and badminton birdies all will easily pass through 

the mesh (Wikipedia, 2013; WikiAnswers, 2013). However, these sports 

are not generally practiced outside of specialized playing areas, so we 

consider the risk of lost equipment unlikely. 

APHIS agreements with landowners are expected to contain a term that 

would meet the requirements of NAGPRA. Agency information to 

residents of colonias could caution parents to advise their children not to 

play near the fence line. 

J. Other Considerations

Federal agencies must ensure that their programs and activities are 

accessible to persons with limited English proficiency as directed by EO 

13166. To meet this need, APHIS conducted outreach to English-speaking 

and Spanish-speaking communities through a variety of public notices and 

door-to-door solicitations about upcoming scoping meetings. All 

stakeholders, including colonia ombudspersons and residents of colonias, 

were invited to the meetings. A translator was present at the meetings to 

ensure all comments were captured and questions adequately addressed. 

The Executive Summary for the Draft and Final EIS will be translated into 

Spanish to provide additional information to communities interested in the 

Proposed Action and the associated employment opportunities. 

APHIS is required to protect farmland when practicable (7 U.S.C. §§ 

4201-4209). Specifically, NRCS ensures Federal programs minimize 

contributions “to the unnecessary and irreversible conversion of farmland 

to nonagricultural uses” while assuring programs are compatible with 

“State, unit of local government, and private programs and policies to 

8. Potential 

Mitigation 

Measures

1. Executive 

Order 13166 – 

Improving 

Access to 

Services for 

Persons with 

Limited 

English 

Proficiency

2. Farmland 

Protection 

Policy Act

124
protect farmland" (§ 4201(b)). The regulations establish requirements and 

guidance for Federal agencies to consider the adverse effects of their 

programs on the preservation of farmland, consider alternative actions that 

could lessen adverse effects, and ensure that their programs are compatible 

with State and local government and private programs and policies to 

protect farmland. 

Federal agencies that are involved in a proposed project that may convert 

farmland to nonagricultural uses need to determine whether their project 

site contains prime, unique, statewide, or locally important farmland. 

While each agency can choose to evaluate farmland in a project area, they 

also may request that NRCS assist with this process. NRCS has the final 

authority for designating important farmlands. 

On October 20, 2011, APHIS engaged in discussion with NRCS on the 

Proposed Action Alternative. In an October 24, 2011 email, NRCS agreed 

that game fencing would not be considered farmland conversion under 

FFPA since it is a reversible action that does not affect the use of cropland 

or productivity (Gabriel, 2011). Therefore, the proposed action of 

installing a game fence on farmland is reversible and falls outside of the 

scope of the FPPA. 

Federal activities cannot affect designated wild and scenic rivers or areas 

immediately adjacent to the designated rivers (16 U.S.C. §§ 1271-1287). 

One hundred ninety-six miles of the Rio Grande extending from Mariscal 

Canyon to the Terrell/Val Verde County line are designated as a wild and 

scenic river. The proposed project is not located within or adjacent to this 

section of the Rio Grande. There are no rivers designated as wild and 

scenic in or associated with the project area; consequently, requirements 

under the NWSRA (§§ 1271-1287) are not applicable to this proposed 

action.

NEPA requires analysis of significant irreversible and irretrievable effects 

associated with a proposed action (40 CFR 1502.16). Irreversible and 

irretrievable commitment of resources applies to the use or consumption 

of resources that is nonrenewable or unrecoverable. At present, APHIS has 

not formally committed resources to the proposed action of game fencing 

installation; therefore, no actions related to the fencing have been taken 

that are considered irreversible or irretrievable. Potential future 

3. National 

Wild and 

Scenic 

Rivers Act

4. Irreversible 

and 

Irretrievable 

Commitment 

of Resources

125
irreversible and irretrievable commitments of resources are described 

below. 

Future Commitments

Native plant communities could be lost as a result of the fence installation, 

which is why APHIS will enter into a contract with a plant surveyor to 

identify any threatened or endangered species that are present in the 

proposed fencing locations. This survey is necessary for the proposed 

action to proceed. At the point that APHIS pays for this service, the costs 

associated with the survey will be considered an irretrievable commitment 

of resources.

Disturbance caused by temporary construction could result in changes in 

wildlife behavior that is irreversible. Wildlife habitat or corridors could be 

lost as a result of the proposed action, but openings in the fencing for 

animals such as ocelots and jaguarundi, in addition to gaps in the fence at 

water resources, would minimize impacts to these species. 

Human effort put forth toward the planning and siting of the proposed 

game fencing is considered irretrievable. The commitment of time and 

labor during the construction process is also considered irretrievable; 

however, temporary local job opportunities could result from the 

installation of the proposed fence segments and are considered beneficial. 

Private property would be used for installation of the proposed game 

fencing. Landowners are not obligated to install the fence on their 

property, so no irretrievable commitments of resources would occur until 

landowners agree to cost-share the fence installation. 

Aside from some soil excavation associated with the burying of fence 

posts, land would not be altered as a result of the proposed action. 

Additionally, if the fence was removed in the future, the holes left in the 

soil by the fence posts could be back-filled. Some run-off could occur 

from soil excavation; however, water resources are not expected to be 

altered in the long-term by the proposed action. 

Cultural and historic resources are considered non-renewable and 

therefore any disturbance to these resources would be irreversible and 

irretrievable. To ensure that this does not occur if the proposed action is 

126
selected, APHIS will continue to work closely with the County Historical 

Commission Chairs in Maverick, Starr, Webb, and Zapata Counties and 

the Tonkawa Tribe of Indians of Oklahoma. 

CFTEP Commitment of Resources

The CFTEP has been in existence since 1906. Since the beginning of the 

eradication effort, program participants developed, tested, and refined tick 

eradication techniques. As a result of this effort, distribution of cattle fever 

ticks went from 15 States to the border of Mexico near the Permanent Tick 

Quarantine Zone in South Texas. Ongoing efforts include treating 

livestock with an approved acaricide, hand-scratch inspections, and 

vacating the pasture. USDA’s Agricultural Research Service also has 

studied the efficacy of medicated bait sites and bait stations to treat whitetailed deer for ticks. This research, the establishment and maintenance of 

the Permanent Tick Quarantine Zone, and Mounted Patrol Inspector 

surveillance contributes to the success of the CFTEP, but it also 

constitutes an irretrievable commitment of resources toward the protection 

of livestock in the United States. As such, the proposed game fencing is 

simply part of a larger effort that has substantial commitments that are 

now irretrievable.

K. Cumulative Impacts

The proposed fencing would mostly occur along right-of-ways adjacent to 

pre-existing highways and on privately owned land that has been 

developed for agriculture and other uses such as energy production. 

Previously described baseline conditions (Chapter 3) in these four counties 

demonstrate a significant amount of human-related disturbance that we 

considered when assessing the magnitude of potential cumulative impacts 

from the Proposed Action Alternative in this EIS. 

A majority of the land in the project area has been altered to facilitate 

agriculture and energy production. Agriculture within the four counties is 

diverse with cattle production, pasture management, and crop production 

as the predominant components. Energy production is also significant with 

more than 17,000 oil and gas leases within the four-county area. We also 

considered the direct and indirect effects from infrastructure projects, such 

as road and highway construction/maintenance, to support access to these 

areas in the context of the Proposed Action Alternative (FHWA, 2007). 

127
Currently, APHIS conducts other activities that may occur within the fourcounty area, primarily related to plant health and vertebrate pest control. 

Plant pest programs such as the Boll Weevil Eradication Program and the 

Imported Fire Ant Quarantine exist within these counties. If detections of 

a boll weevil or imported fire ant are made, chemical treatments are 

applied to specific locations (in the case of the boll weevil) or to 

quarantined products shipped to an area not under quarantine, which is the 

case with imported fire ant. These treatments are infrequent and are made 

in crop fields or in nurseries using products that are registered by EPA for 

a wide variety of agricultural and non-agricultural uses. 

The potential human health impacts related to the Proposed Action are 

expected to be minimal, and in the context of potential cumulative impacts 

to past, present, and future activities, the impacts would be incrementally 

minor. The proposed fence is designed to connect with pre-existing 

fencing to decrease the probability of tick-infested cattle and wildlife from 

entering areas that are tick free. Direct effects from the Proposed Action 

Alternative would include ground disturbance and noise during the 

placement and maintenance of fencing; however, this effect would be 

short-term as the fence is completed and minor in relation to other 

activities in the area such as road traffic. 

A positive cumulative impact from the additional game fencing as part of 

an integrated strategy in managing cattle fever ticks would be a reduction 

in interactions between tick-infested cattle coming from Mexico with 

those in the United States. The reduction in ticks and associated diseases 

would provide economic benefits to the livestock industry by providing 

economic stability and would position the U.S. livestock industry to 

remain competitive as markets evolve (Miller et al., 2013; Pérez de León

et al., 2012). Economic benefits to taxpayers may also occur through 

decreased costs to USDA and the TAHC to maintain the CFTEP. The 

reduction in ticks also could result in a reduction of chemical control 

measures used as part of the CFTEP. The acaricides used in the CFTEP 

have other agricultural and/or residential uses; consequently, we cannot 

estimate the total amount of each product used, in addition to those with 

similar modes of action used by others in the affected counties. The 

limited chemical use in the CFTEP suggests a minor contribution to 

overall use when factoring in current and future uses, and therefore, the 

reductions in chemical loading would not be expected to be significant. 

1. Human 

Population

128
Due to the restrictions in how chemical control measures are managed by 

the CFTEP, risk to the general human population is not expected. 

However, any reductions in chemical use would benefit workers by 

reducing exposure and subsequent risk. The reduction in the need for 

chemical control measures also would have a beneficial cumulative impact 

to the livestock industry in reducing the probability of chemical resistance 

developing in cattle fever ticks, which has been observed in Mexico (Pérez 

de León et al., 2012). 

The potential for cumulative impacts to ecological resources is related

primarily to those species that may have their movements impeded by the 

additional fencing that is proposed in this EIS. The use of fencing can 

impact emigration, immigration, and migration of certain species and can 

result in fragmentation of populations with a resulting decrease in gene 

flow (Gadd, 2010; Lindsey et al., 2012; Mbaiwa and Mbaiwa, 2006). This 

may be particularly critical for species of concern such as the federally 

listed ocelot and jaguarundi. Habitat destruction has already contributed 

significantly to the decline of these species; fencing may pose an 

additional threat (FWS, 2010; FWS, 2012 a).

Cumulative impacts to non-target and/or non-listed species such as 

bobcats from the proposed fencing is difficult to quantify; however, when 

compared to the fencing that already exists in this area and the large-scale 

loss of habitat from agriculture, energy production, and the impacts of 

highway construction and expansion, the cumulative impacts from the 

Proposed Action Alternative in this EIS are not expected to contribute 

significantly when compared to current and future activities already 

underway. The additional fence would not be continuous but would have 

multiple openings due to roads, arroyos, and other bodies of water that 

would allow for the movement of wildlife. APHIS is also working with 

the FWS to incorporate openings at the bottom of fences that would allow 

unimpeded movement of threatened and endangered species and other 

wildlife except deer while maintaining the separation of potentially tickinfested cattle and deer from areas that are free from cattle fever ticks. 

Other aspects of the CFTEP, such as chemical control measures and trail 

maintenance, should be considered when assessing cumulative impacts to 

ecological resources. We expect that these cattle fever tick management 

measures contribute less to the cumulative impacts to non-target wildlife, 

such as mammals, compared to fence construction and maintenance. 

2. Ecological 

Resources

129
Chemical use in the CFTEP is restricted in such a way to avoid non-target 

fish and wildlife impacts, or the type of chemical poses a low risk to most 

non-target populations. Trails that allow for surveillance of cattle and 

wildlife coming from Mexico have been in existence since approximately 

1938 and have resulted in the loss of some native habitat. Maintenance of 

these trails requires periodic clearing on private and public property. The 

loss of habitat is expected to be minor, relative to the economic 

development that has occurred in these four counties since the trails were 

established. The length of trail is not expected to increase in the future and 

maintenance of the trail would be coordinated with private landowners as 

well as affected public land management agencies to minimize impacts to 

ecological resources. 

Other considerations for assessing cumulative impacts include ongoing 

APHIS programs in Maverick, Starr, Webb, and Zapata Counties. In the 

case of APHIS programs such as Imported Fire Ant Quarantine, chemical 

treatments are made to commodities such as containerized plants and sod 

in highly disturbed areas prior to shipment. These treatments occur in 

production nurseries and – due to the lack of suitable habitat for non-target 

wildlife – we do not expect treatments to result in population-level 

impacts to ecological resources. In the Boll Weevil Eradication Program, 

infrequent treatments are made to cotton fields during the day. Impacts to 

vertebrates that could have their movements affected by the fence would 

not be expected to be affected by these treatments since many are 

nocturnal and avoid the noise disturbance that would occur during 

treatment. In addition, off-site impacts to food and shelter for these types 

of wildlife would not be impacted by chemical treatments used in these 

programs. Vertebrate pest control measures implemented by APHIS are on 

an as-needed basis and currently only occur in small areas within Webb 

County. It is difficult to predict whether these types of actions would 

expand to the other three counties. Nevertheless, consultation under the 

Endangered Species Act on listed species, as well as mitigation measures 

built into the programs and listed on pesticide labels, are designed to 

minimize impacts to listed species such as the ocelot (FWS, 2010) and 

other mammals (FWS, 2012 a; FWS, 2012 b) that could be impacted by 

vertebrate pest control and the proposed fence. 

Activities unrelated to APHIS also may contribute to the cumulative 

impacts to non-target mammals in this area. The maintenance of Highway 

83 and other roads designed to provide access to residential, agriculture, 

130
and energy production areas may pose a threat to mammals that also could 

be impacted by additional fencing. Current and future activities, such as 

the improvement of U.S. Highway 83, would be anticipated to increase 

vehicular traffic. This in turn could result in a greater probability of car 

strikes to animals that cross these areas while moving between areas of 

suitable habitat. Culverts and bridges that may occur along these areas 

would help to reduce this potential impact allowing animals to move under 

roads and highways. 

Cumulative impacts to soil, water, and air quality are not expected to be 

significant for the Proposed Action and the No Action Alternative. Current 

and future activities related to highway traffic and maintenance may 

impact environmental quality due to construction activities and increased 

road traffic. The impacts from the actions discussed in this EIS, however, 

are expected to result in only minor impacts or transient impacts, so any 

incremental cumulative impacts would be negligible. Soil disturbance 

relative to fence construction would be short-term and isolated since the 

fence would be installed at a rate of approximately one mile per day. 

Maintenance of the fence could result in some soil erosion since 

vegetation removal could expose soil to water and wind erosion. 

A variety of soil types exist within the four counties, with soils having 

slight to severe erosion potential from wind and rain (Molina and Guerra, 

2011; Sanders and Gabriel, 1985; Stevens and Arriaga, 1977; Thompson 

et al., 1972). The amount of erosion from fence construction and 

maintenance, however, would be minor relative to the erosion potential 

from current and future farming and energy extraction activities, as well as 

U.S. Highway 83 use and maintenance (FHWA, 2007; TXDOT, 2013). 

More than 17,000 oil and gas leases currently exist within the four-county 

area, with Maverick, Webb, and Zapata Counties comprising the top 100 

counties (254 counties total) in Texas for energy production (TXRC, 

2013). 

Fencing would not be constructed or maintained within proximity to 

aquatic resources, so there is incrementally minor potential for cumulative 

impacts from sedimentation, which would be the greatest threat to water 

quality from fence construction and maintenance. Waterways that are 

currently listed as impaired or are maintaining designated uses under the 

CWA (33 U.S.C. §§ 1251-1387) would be expected to continue under the 

No Action or Proposed Action Alternative as it relates to fence 

3. Environmental 

Quality

131
construction. However, agriculture and energy-extraction activities, as 

well as expanded highway use in the future, could impact these 

designations. Regulations regarding non-point source pollution from these 

types of activities, as well as State and Federal programs designed to assist 

landowners in reducing impacts to soil and water, would help reduce the 

potential for soil and water impacts (TSSWCB, 2013). 

Similar to cumulative impacts to soil and water, the potential for 

cumulative impacts to air quality are anticipated to be incrementally minor 

and transient under the No Action or Proposed Action Alternative. 

Emissions during the construction and maintenance of the fence would be 

minor relative to the ongoing and future emissions from highway traffic, 

agricultural production, and energy extraction activities that are prevalent 

within the four counties. Ambient air quality criteria (for attainment zones 

and mobile source air toxics, 40 CFR § 50) would not be reached by the 

Proposed Action Alternative and would only result in incrementally minor 

and transient increases in air quality pollutants. A comparison of the 

greenhouse gas emissions in Maverick County from mobile road and nonroad sources to the amount of greenhouse gases estimated in this EIS 

demonstrates a less than 0.2% annual contribution from the Proposed 

Action Alternative (EPA, 2013). Future actions that could increase 

emissions such as highway expansion resulting in more traffic are difficult 

to quantify since future emissions from mobile sources are expected to 

decrease due to regulations regarding fuel mileage standards and 

emissions. However, the contribution from the proposed alternative would 

still remain minor to the overall emissions for the four-county area. In 

addition, when factoring air emissions from other sources such as 

agriculture and energy production, the contribution to air emissions from 

the proposed alternative becomes incrementally smaller. 

Available data for emissions related to oil and gas exploration and 

production sources in the four counties evaluated in this EIS indicate that 

these emissions would be substantially larger on a daily and annual basis 

when compared to the potential emissions from equipment used to install 

and maintain the proposed fence and adjacent vegetation (TCEQ, 2007). 

The cumulative impacts from the Proposed Action Alternative when 

assessed in relation to the current baseline and past, present, and future 

activities constitutes a small incremental change to the human 

environment. Some of these cumulative changes may be positive such as 

4. Conclusion

132
the reduction in cattle fever ticks and the associated economic benefits 

from having tick-free cattle. To preserve environmental quality for the 

human population and ecological resources, potentially negative 

cumulative impacts are minimized throughout the proposed alternative by 

following best management practices during construction.

133
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134
Appendix A. Preparers 

U.S. Department of Agriculture

Animal and Plant Health Inspection Service

4700 River Road 

Riverdale, MD 20737 

Matthew T. Messenger

Staff Entomologist

 B.S. Entomology 

 M.S. Entomology 

 Ph.D. Entomology 

Background: Staff Entomologist and Program Manager of the Cattle 

Fever Tick Eradication Program. Five years of service with APHIS; 

previously employed by The Dow Chemical Company as a Field Research 

Scientist, developing and evaluating urban pest management monitoring 

and control methods. 

EIS Responsibility: Veterinary Services CFTEP contact – co-authored 

executive summary and reviewed and contributed to sections in chapters 

1, 2, 3, and 4 and appendices of draft EIS. 

Michelle L. Gray

Environmental Protection Specialist

 B.S. Biology 

 M.S. Zoology 

Background: Environmental protection specialist with expertise in 

wildlife biology and toxicology. Ten years of service in APHIS. 

Experienced in preparing environmental documents for APHIS programs. 

Experienced in environmental compliance especially as it relates to the 

Migratory Bird Treaty Act and the Endangered Species Act. 

EIS Responsibility: EIS team leader – wrote part of chapters 1, 2, 3, and 

4. Reviewed chapters and appendices. Responsible for leading the 

preparation of chapters 3 and 4 of the draft EIS. 

Appendix A. Preparers A-1
Allan N. Auclair

Systems Ecologist

 B.S. General Science

Ph.D. Plant and Systems Ecology 

Background: Risk scientist with expertise on pest risk assessment, pest 

outbreak dynamics, and the role of climate drives and climate change on 

pest incidence. Eight years of service in APHIS. Experienced in risk 

analysis especially as it relates to risk assessment of exotic pests entering 

on commodities under import permit application; climate as a drive on the 

outbreak of high-threat pests; and compliance to climate change and 

invasive pest legislation including Executive Orders 13122 and13514 and 

Departmental Regulation 1070-001. 

EIS Responsibility: EIS analyst – assessed the influence of climate and 

climate change impacts of fencing to control the spread of cattle fever 

ticks along the U.S.-Mexican border. 

Samantha B. Floyd 

Biological Scientist

 B.S. Biology

 M.S. Environmental Science and Policy

Background: Biological scientist with expertise in pesticide research and 

regulatory policy. More than ten years of service with APHIS. Prepares 

and provides assistance on environmental documents for APHIS 

programs. Experienced in managing environmental compliance as it 

relates to the Federal Insecticide, Fungicide, and Rodenticide Act. 

EIS Responsibility: EIS analyst – prepared the chapter 4 section of the 

draft EIS regarding the Farmland Protection Policy Act and reviewed 

other sections of Chapter 4. 

Vicki L. Gutierrez

Environmental Protection Specialist

 

Background: Paralegal studies. More than 20 years of experience working 

on NEPA documents as a writer/editor and team leader. More than

36 years of experience working in APHIS, including as a compliance 

assistant for Animal Welfare Act and Horse Protection Act alleged 

A-2 Appendix A. Preparers
violation cases and as a management analyst in planning and information 

resources management. 

EIS Responsibility: EIS team leader – responsible for leading the 

preparation of EIS public scoping meetings and the development of 

chapters 1 and 2 of the draft EIS. 

Vivian A. Miller

Environmental Protection Specialist

 B.S. Biology

M.Ed. Secondary Education, Biology 

Background: Environmental protection specialist with more than three

years of experience in preparing and reviewing NEPA compliance 

documents for APHIS. 

EIS Responsibility: EIS analyst – wrote sections of chapters 3 and 4 of 

the draft EIS. 

Ann M. Nasr

Writer/Editor

 B.A. English-Latin

Background: More than 20 years of clerical, administrative, and editorial 

service with APHIS. Previously employed in private industry as an editor 

and publications coordinator. 

EIS Responsibility: EIS Editor – desktop publishing of the draft EIS 

(including editing, format, and document security); supportive 

coordination and planning. 

Amy W. Shalom 

Environmental Protection Specialist

B.A. Literature

Background: Environmental protection specialist, preparing and 

reviewing NEPA compliance documents. Nine years of experience with 

APHIS. 

Appendix A. Preparers A-3
EIS Responsibility: EIS analyst – wrote portions of chapters 3 and 4 of 

the draft EIS. 

Daniel L. Smith

Environmental Protection Specialist

 B.A. Chemistry

 B.S. Biology 

 M.S. Environmental Science 

Background: Environmental protection specialist with expertise in GIS, 

environmental and systemic toxicology, and chemical and pesticide fate. 

More than seven years of experience with APHIS. Experienced in GIS 

mapping for endangered species and natural resources and in preparing 

NEPA compliance documents. Previously employed by The Army Corps 

of Engineers in Anchorage, Alaska as a regulatory specialist, enforcing 

and permitting Clean Water Act Section 404 fill activities. 

EIS Responsibility: EIS analyst – wrote portions of chapters 3 and 4; 

prepared maps using GIS technology. 

Rhonda R. Solomon 

Environmental Protection Specialist

 B.S. Biology 

 J.D. Law 

Background: Environmental protection specialist with more than 8 years 

of experience in the National Environmental Policy Act. Six years of 

environmental compliance with APHIS. 

EIS responsibility: EIS analyst – assisted in preparations for the EIS 

public scoping meetings and for issues regarding colonias and 

Environmental Justice (EO 12898). 

Eileen M. Sutker

Environmental Protection Specialist

 B.S. Botany 

 M.S. Plant Pathology 

 Ph.D. Plant Pathology 

 J.D. Law 

A-4 Appendix A. Preparers
Background: Environmental protection specialist with expertise in risk 

analysis, permitting, and regulatory policy. More than 11 years of service 

with APHIS. Expertise in environmental compliance as it relates to 

commodity imports and interstate movement of plant pests under the Plant 

Protection Act. Experienced in preparing environmental documents used 

by APHIS programs. 

EIS Responsibility: EIS Analyst – prepared information for the climate 

change and human health and safety sections of chapters 3 and 4. 

Fan Wang-Cahill

Environmental Health Specialist

B.S. Biology 

M.S. Hydrobiology 

Ph.D. Ultrastructure/Cell Biology

Background: Eighteen years of experience in human health risk 

assessment for environmental contaminants at Superfund, Resource 

Conservation and Recovery Act (RCRA) and state-regulated contaminated 

facilities. Joined APHIS in November 2012 to lead human health risk 

assessment portions of NEPA documents and to assist in Environmental 

Justice compliance efforts (EO 12898). 

EIS Responsibility: EIS analyst – wrote the livestock health and human 

health and safety sections of chapter 4 of the draft EIS. 

Jim E. Warren 

Ecologist 

 B.S. Forest Ecology 

 M.S. Entomology 

 Ph.D. Environmental Toxicology 

Background: More than six years of experience working for APHIS 

preparing ecological risk assessments and providing assistance on 

environmental compliance. Prior experience before joining APHIS 

includes other government and private sector work regarding ecological 

risk assessments related to various environmental regulations. 

EIS Responsibility: EIS analyst – Prepared the cumulative effects section 

of chapter 4 and served as a reviewer for other sections of the draft EIS. 

Appendix A. Preparers A-5
Phillip E. Washington 

Environmental Engineer 

B.S Chemical Engineering 

 M.S. Environmental Engineering 

Background: Environmental protection specialist with expertise in the 

National Historic Preservation Act, Environmental Justice (EO 12898), 

Native American issues, and organizational development. Eight years of 

service with APHIS. Twelve years of prior experience in private industry 

(E.I. DuPont de Nemours & Company Inc.) and the Federal government

(U.S. Air Force Headquarters Air Mobility Command) as an 

environmental engineer. 

 

EIS Responsibility: EIS analyst – Wrote chapter 4 sections on 

Environmental Justice (EO 12898), Native American Sacred Sites (EO 

13007) and the Native American Graves Protection and Repatriation Act 

(Public Law 101-601). 

Tracy A. Willard 

Ecologist 

 B.S. Biology

 M.S. Entomology 

 Ph.D. Entomology 

Background: Ecologist with expertise in entomology and integrated pest 

management. Twelve years of service with APHIS. Experience in 

environmental compliance, especially associated with the Endangered 

Species Act in the context of biological control and pest management. 

Prepares and provides assistance on environmental documents for APHIS 

programs. 

EIS Responsibility: EIS Analyst—wrote public scoping section for 

chapter 1, the threatened and endangered species section of chapter 3, and

the Endangered Species Act, Migratory Bird Treaty Act, and Bald and 

Golden Eagle Protection Act sections of chapter 4. 

A-6 Appendix A. Preparers
Appendix B. Review and Consultation 

The following individuals have reviewed draft sections of this 

Environmental Impact Statement (EIS) or were consulted on critical issues 

that have been addressed in this EIS. The expertise and concerns of these 

individuals were considered during the development of this EIS; the 

content of this EIS does not necessarily reflect their individual views and 

opinions. 

David A. Bergsten Supervisory Biological Scientist

 USDA, APHIS, PPD

 Environmental and Risk Analysis Services 

 4700 River Road, Unit 149 

 Riverdale, MD 20737

Mr. Edwin Bowers Field Operations Supervisor 

 USDA, APHIS, VS

 Cattle Fever Tick Eradication Program 

 120 San Francisco Avenue 

 Laredo, TX 78040 

Dr. Dee Ellis Executive Director

 Texas Animal Health Commission

 2105 Kramer Lane 

 Austin, TX 78758 

Dr. Matthew T. Messenger Program Manager/ Staff Entomologist 

 USDA, APHIS, VS

 Cattle Fever Tick Eradication Program

 4700 River Road, Unit 43 

 Riverdale, MD 20737 

 

Ms. Diana Brandon 

County Historical Commission Chair – Zapata County 

P.O. Box 56 

Zapata, TX 78076 

Mr. Joseph Moreno 

County Historical Commission Chair – Webb County 

1120 East Calton Road 

Laredo, TX 78041 

Principal

Reviewers

Principal 

Federal 

and State 

Agencies 

Consulted

Appendix B. Review and Consultation B-1
Mr. Donald L. Patterson 

NAGPRA Coordinator 

Tonkawa Tribe of Indians of Oklahoma 

1 Rush Buffalo Road 

Tonkawa, OK 74653 

Ernesto Reyes

U.S. Fish & Wildlife Service

Alamo Ecological Services Sub-Office

3325 Green Jay Road 

Alamo, TX 78516-7324 

Dawn Whitehead

Assistant Field Supervisor 

U.S. Fish and Wildlife Service 

Corpus Christi Ecological Services Office

6300 Ocean Drive, Unit 5837 

Corpus Christi, TX 78412 

Salvador Salinas

State Conservationist 

USDA Natural Resources Conservation Service 

101 South Main Street

Temple, TX 76501 

Principal 

Federal 

and State 

Agencies 

Consulted 

(cont’d)

B-2 Appendix B. Review and Consultation
Appendix C. Summary of and Responses to 

Comments on Draft EIS

(Reserved for final CFTEP EIS.)

Appendix C. Summary of and Responses to Comments on Draft EIS C-1 
(This page is intentionally left blank.)

C-2 Appendix C. Summary of and Responses to Comments on Draft EIS
Appendix D. Distribution List

Serafin M. Aguirre

Suite 130 – SWCD#253 

2210 N. Veterans Blvd. 

Eagle Pass, TX 78852 

Butch Garcia

6749 E. Hwy 83 

Rio Grande City, TX 78582 

Andy Garza

104 Magnolia 

Falfurrias, TX 78355 

Rebecca Gonzalez

4157 S. US Hwy 83 

Zapata, TX 78076 

Eduardo Gracia, Jr.

Texas Department of Transportation 

P.O. Box 907 

Hebbronville, TX 78361 

Eduardo Gracia, Jr. 

P.O. Box 120 

Lopeno, TX 78564 

Mike Graham

Texas Dept of Transportation – Laredo 

District

1817 Bob Bullock Loop 

Laredo, TX 78043 

Gregor Haby

P.O. Box 44 

El Indio, TX 78860 

Elias Herrera, Jr.

105 Kennedy Street 

Zapata, TX 78076 

Blanca Juarez

101 S. Washington Street 

Rio Grande City, TX 78582 

Dr. Adalberto A. Pérez de León 

USDA ARS KBUSLIRL

2700 Fredericksburg Road 

Kerrville, TX 78028 

Samuel Rodriguez, Jr.

P.O. Box 464 

Rio Grande City, TX 78582 

David H. Romo 

USDA APHIS VS

P.O. Box 157 

El Indio, TX 78860 

Javier Salinas

2110 Summer Breeze Road 

Mission, TX 78572 

Victor L. Villarreal

207 W. Del Mar Blvd 

Laredo, TX 78045

Appendix D. Distribution List D-1 
(This page is intentionally left blank.)

D-2 Appendix D. Distribution List
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E-16 Appendix E. References
Appendix F. Glossary

A 

A pesticide that is used to kill ticks. 

Property bordering an infested premises. 

B 

Describes the variety of plant, animal, and microbial life found within an 

ecosystem. 

Caused by parasites that are carried by cattle fever ticks and can cause 

illness or death in cattle. 

C 

A term used in the southwestern States to describe a subdivision where 

developers divide the land into small lots and offer affordable housing to 

low-income families.

E 

Prevalent in a specific area. 

A species that was introduced to a habitat where it is not native. 

G 

Emitted from natural processes and human activities and consist of water 

vapor, carbon dioxide, methane, nitrogen oxide, ozone, hydrocarbons, and 

chlorofluorocarbons.

H 

An inspection of livestock that allows the inspector to touch and see all 

parts of the livestock. (4 TAC § 41.1(20)). 

Adjacent 

Premises

Biodiversity

Endemic

Exotic

Species

Handscratch 

inspection

Colonia

Acaricide

Bovine 

Babesiosis

Greenhouse 

Gas

Endemic

Appendix F. Glossary F-1
I 

Property with confirmed Rhipicephalus annulatus or R. microplus

populations. The presence of even a single cattle fever tick will cause

premises to be placed under quarantine as an infested premises. 

A species that is not native to an ecosystem and whose introduction is 

likely to cause harm to humans or the environment. 

L 

Physical features and soil resources. 

USDA defines “livestock” in the Animal Health Protection Act as all 

farm-raised animals (7 U.S.C. §§ 8302(10)). In Texas, cattle are the 

primary tick-susceptible livestock in the proposed fence areas. Other ticksusceptible livestock include horses, sheep, angora goats, and swine. 

N 

Plants that are (or have the potential to be) harmful to human or animal 

health and the environment. 

P 

Defines the boundary between the Permanent Tick Quarantine Zone and 

the tick-free area. 

An approximately 580-mile-long stretch of land from Del Rio to 

Brownsville, Texas, ranging in width from almost 125 yards (0.07 miles) 

to approximately 8 miles. 

Fine particulate matter emitted from sources such as diesel engines, power 

plants, and refineries. 

Permanent 

Tick 

Quarantine 

Zone 

Infested 

Premises

Permanent 

Tick 

Quarantine 

Line

Livestock

Invasive 

Species

Land 

Characteristics

Noxious 

Weeds

Primary 

Pollutant 

F-2 Appendix F. Glossary
S 

Caused by a chemical reaction between two primary pollutants forming 

nitrate and sulfate compounds. 

T 

Large area containing infested, adjacent, exposed, vacated, and checked 

premises. 

U

Hoofed animals. 

V 

Property with a tick quarantine issued, and all livestock have been 

removed, inspected, and treated. The property must remain vacant for a 

minimum of six months during the summer or nine months if the 

quarantine is issued in the fall. 

An insect or other organism capable of transmitting a pathogenic virus, 

bacteria, or fungus. 

W 

An area of land that contributes water to a river or stream.

Temporary 

Preventative 

Quarantine 

Area

Ungulates

Vacated 

Premises

Vector

Secondary 

Pollutant

Watershed

Appendix F. Glossary F-3
(This page is intentionally left blank.)

F-4 Appendix F. Glossary
Appendix G. Index

(Reserved for final CFTEP EIS.)

Appendix G. Index G-1 
(This page is intentionally left blank.) 

G-2 Appendix G. Index
Appendix H. Maps of Proposed Fence Segments

The estimated measurement of locations where there is a need for game fencing to control the 

spread of cattle fever ticks is 5.25 miles for Maverick County, 12.46 miles for Starr County, 

7.8 miles for Webb County, and 45.82 miles for Zapata County, for a total of approximately 

71 miles overall. The total amount of game fencing installed would depend upon landowners’ 

consent for game fencing on their properties and cost-share agreements with APHIS. 

The approximate location of the fence segments is displayed on the maps in this appendix, and 

the information pertaining to each map is summarized below:

• Overview Map – All fence segments proposed in Maverick, Starr, Webb, and Zapata 

counties. 

• Map A – Northernmost short stretch of game fence along Mines Road (north of El Indio) 

in Maverick County. The fence would be located on the south (river side) of Mines Road. 

The length of the game fencing segment is approximately 1.57 miles. 

• Map B – The fence would be located on the north side of Mines Road just north of town 

center El Indio in Maverick County. The length of the game fencing segment is 

approximately 1.0 mile. 

• Map C – The fence would be located on the north side of Mines Road in Maverick 

County. The length of the game fencing segment is approximately 2.4 miles. 

• Map D – The fence would be located on the south side of U.S. Highway 83 in Webb 

County. The length of the game fencing segment is approximately 7.8 miles. 

• Map E to K – Approximately 56.44 miles of game fence is proposed in Zapata and Starr 

counties in place of existing highway right-of-way fence on the south side of U.S. 

Highway 83. The fence would start just south of the Webb County/Zapata County line at 

mile marker 752 in rural locations only and skipping roads and water resources and 

extending to Roma, Texas, ending north of Roma High School in Starr County, to mile 

marker 766. One, two-mile portion of the proposed fencing between the towns of San 

Ygnacio and Zapata would be installed on the north side of U.S. Highway 83 between the 

southwest corner of the high-fenced Las Avispas pasture (approximately 9.57 miles 

southeast of San Ygnacio) and the northwest corner of the high-fenced Alexander pasture 

(approximately 3.17 miles northwest of Zapata).

Appendix H: Maps of Proposed Fence Segments H-1 
(This page is intentionally left blank.)

Appendix H: Maps of Proposed Fence Segments H-2 
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 9 18 27 36 4.5

Miles

Proposed Tick Control Barriers along the Tick Eradication Quarantine Line, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.6 1.2 1.8 2.4 0.3

Miles

A - Proposed Tick Control Barrier. Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

00.050.1 0.2 0.3 0.4

Miles

B - Proposed Tick Control Barrier. Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.8 1.6 2.4 3.2 0.4

Miles

C - Proposed Tick Control Barrier. Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 1 2 3 4 0.5

Miles

D - Proposed Tick Control Barrier. Webb County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.5 1 1.5 2 0.25

Miles

E - Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.5 1 1.5 2 0.25

Miles

F- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.5 1 1.5 2 0.25

Miles

G- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.5 1 1.5 2 0.25

Miles

H- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.5 1 1.5 2 0.25

Miles

I - Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.6 1.2 1.8 2.4 0.3

Miles

J - Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.7 1.4 2.1 2.8 0.35

Miles

K - Proposed Tick Control Barrier. Starr County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
Appendix I. Water Bodies and Floodplains

The proposed fencing area includes a total of 27 reservoirs, streams, rivers, ephemeral (shortlived), intermittent, and perennial drainage features that are considered jurisdictional waters of 

the United States and are subject to CWA regulations (40 CFR 136, 230-233). The major water 

bodies in this area include the Rio Grande bordering the west or southwest of all four counties, 

the Main Canal in Maverick County, Falcon Dam on the west border of Zapata and Starr 

counties, and Falcon Reservoir and its three arms that extend into Zapata County (Arroyo Burro, 

Arroyo del Tigre Grande, and Arroyo del Tigre Chiquito). Minor water bodies include streams 

and arroyos. The proposed fencing would cross 100-year floodplains in 12 locations in three 

counties (Starr, Webb, and Zapata). 

The water bodies and floodplains in relationship to the proposed fencing are displayed on maps 

in this appendix with information pertaining to each map summarized below:

• Map A – Rosita Creek and an unnamed creek in Maverick County. 

• Map B – Cuevas Creek and an unnamed creek in Maverick County. 

• Map C – Two unnamed streams in Maverick County. 

• Map D – Carricitos Creek and five unnamed creeks in Webb County. 

• Map E – Dolores Creek in Zapata County. 

• Map F – Arroyo Salado, Arroyo San Francisco, and El Grullo Creek in Zapata County. 

• Map G – Falcon Reservoir, Marcial Creek, Chapote Creek, and Arroyo Zacataso in 

Zapata County. 

• Map H – Arroyo Zacataso, Arroyo Molletes, Arroyo Ranchito, Arroyo San Bartolo, and 

Chapote Creek in Zapata County. 

• Map I – Arroyo Clareno, Arroyo Del Tigre Grande, and three unnamed streams in Zapata 

County. 

• Map J – Arroyo Del Tigre Chiquita, Arroyo Los Guajes, and Arroyo Tinijas in Zapata 

County. 

• Map K – Arroyo Morteros, Arroyo Minita, Arroyo Del Tigre, Arroyo de Los Mudos, 

Ramirez Creek, and two unnamed creeks in Starr County. 

• 100-Year Flood Zones, Maverick County – one segment of fencing could be located in or 

near the floodplain along the southern edge of the county. 

• 100-Year Flood Zones, Webb County – Fencing could cross several floodplains in this 

county. 

• 100-Year Flood Zones, Zapata County – Fencing could cross several floodplains in the 

southwestern portion of this county. 

Appendix I. Water Bodies and Floodplains I-1 
(This page is intentionally left blank.)

I-2 Appendix I. Water Bodies and Floodplains
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Rosita Creek

Unnamed Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.350.7 1.4 2.1 2.8

Miles

A - Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Cuevas Creek

Unnamed Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.2 0.4 0.8 1.2 1.6

Miles

B - Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Unnamed Stream

Unnamed Stream

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.3250.65 1.3 1.95 2.6

Miles

C - Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Carricitos Creek

Unnamed Creek

Unnamed Creek

Unnamed Creek

Unnamed Creek

Carricitos Creek

Unnamed Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.4750.95 1.9 2.85 3.8

Miles

D - Webb County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Dolores Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.3 0.6 1.2 1.8 2.4

Miles

E - Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Arroyo Salado

Arroyo San Francisco

El Grullo Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

00.3750.75 1.5 2.25 3

Miles

F - Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Falcon Reservoir

Marcial Creek

Arroyo Zacataso

Chapote Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.30.6 1.2 1.8 2.4

Miles

G - Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Arroyo Zacataso

Chapote Creek

Arroyo Molletes

Arroyo Ranchito

Arroyo San Bartolo

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.30.6 1.2 1.8 2.4

Miles

H - Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Arroyo Del Tigre Grande

Unnamed Stream

Unnamed Stream

Arroyo Clareno

Unnamed Stream

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.45 0.9 1.8 2.7 3.6

Miles

I - Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Arroyo Del Tigre Chiquita

Arroyo Los Guajes

Arroyo Tinijas

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.20.4 0.8 1.2 1.6

Miles

J - Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Arroyo Minita

Arroyo Del Tigre

Arroyo de Los Mudos

Ramirez Creek

Unnamed Creek

Unnamed Creek

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.4 0.8 1.6 2.4 3.2

Miles

K - Starr County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.

Arroyo Morteros
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 1.252.5 5 7.5 10

Miles

100-Year Flood Zones, Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

100 Year Flood Zones

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 1 2 4 6 8

Miles

100-Year Flood Zones, Webb County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

100 Year Flood Zones

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: March 12, 2013 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 2.254.5 9 13.5 18

Miles

100-Year Flood Zones, Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

100 Year Flood Zones

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
Appendix J. Socioeconomics 

Appendix J1 - Colonias and Schools

The Geographic Names Information System (GNIS) Gazetteer WMS from the National Map 

(http://services.nationalmap.gov/ArcGIS/rest/services/geonames/MapServer) was used to search 

for colonias and schools located in the surrounding areas of the proposed fence segments. The 

first map in this appendix shows all of the proposed fence segments. The indices A through K on 

this map represent each individual fence segment. 

The colonias and/or school information identified on each map is summarized below: 

• Map index A – Proposed Tick Control Barrier, Maverick County, Texas – Loma Linda 

#1 and Chula Vista 1-5 are the closest colonias located near the northern tip of the 

proposed fence segment; and no school is identified on this map. 

• Map index B – Proposed Tick Control Barrier, Maverick County, Texas – El Indio 

Townsite colonias are located around the proposed fence segement; no school is 

identified on this map. 

• Map index E – Proposed Tick Control Barrier, Zapata County, Texas – Dolores is the 

closest colonia located adjacent to the northern portion of the proposed fence segment; no 

school is identified on this map. 

• Map index F – Proposed Tick Control Barrier, Zapata County, Texas – San Ygnacio and 

Valle Verde are the closest colonias located in between two proposed fence segments. 

Benavides Elementary School is located approximately 0.3 mile from the closest 

proposed fence segment. 

• Map index G – Proposed Tick Control Barrier, Zapata County, Texas – In addition to San 

Ygnacio and Valle Verde colonias and Benavides Elementary School show on Map index 

F, San Ignacio Viejo Unit 2 and Ramireno colonias are adjacent to the proposed fence 

segments to the south. No additional school is identified on this map. 

• Map index H – Proposed Tick Control Barrier, Zapata County, Texas – Ranchito San 

Jose is the closest colonia located approximately 0.2 miles north of the proposed fence 

segment. Five schools (Zapata Junior High School, Zapata Middle School, Zapata High 

School, Zapata North Elementary School, and Zapata South Elementary School) are 

identified on this map. Zapata Junior High School is the closest (approximately 1.5 miles) 

school south of the proposed fence segment. 

Appendix J. Socioeconomics J-1 
• Map index J – Proposed Tick Control Barrier, Zapata County, Texas – Morales / 

Sanchez, Lopeno, and New Falcon colonias are adjacent to the proposed fence segments; 

no school is identified on this map. 

• Map index K – Proposed Tick Control Barrier, Starr County, Texas – Lago Vista, Indio 

#1 and #2, Salineno North, Los Arrieros, and La Minita colonias are located adjacent to 

the proposed fence segments. 

Appendix J2 - Socioeconomic Information

Socioeconomic information for Maverick, Starr, Webb, and Zapata Counties (table J2.1) was 

obtained from an online search of the U. S. Census Bureau database (USCB, 2007-2011). The 

American Community Survey at the county level was based on 5-year estimates, from 2007 

through 2011. 

Table J2.1 Socioeconomic Information for Maverick, Starr, Webb, and Zapata Counties

Socioeconomic Criteria Maverick 

County 

Starr 

County

Webb 

County

Zapata 

County

Median family income (dollars) $32,548 $28,779 $39,335 $27,600

Percentage of families and people whose income in 

the past 12 months is below the poverty level (all 

families) 28.80% 34.80% 25.90% 33.80%

Residents in labor force (percentage) 58.90% 54.70% 62.50% 53.60%

Residents in agriculture, forestry, fishing and hunting, 

and mining (percentage) 4.20% 6.30% 2.40% 16.00%

Foreign born (number of people) 18,612 18,244 72,839 3,172

Median age (years) 30.2 28.9 27.6 29.2

Speak a language other than English (citizens 18 

years and over) (percentage) 93.40% 95.10% 91.80% 84.20%

Speak English "very well" (percentage) 56.00% 62.30% 54.20% 72.70%

The socioeconomic information (table J2.2) is based on the residential populations living within 

a 0.25 mile radius along the proposed fence segments. The residential population information is 

presented in two areas (Rosita and El Indio) for Maverick County because two separate fence 

segments are proposed in this county. This information was obtained from USEPA EJView 

Census 2010 Summary Report (http://www.epa.gov/EJView). The 0.25 mile distance was 

selected to represent an estimated impacted area within the routinely traveled walking distance of 

the fence. Webb County is not included in table J2.2 because the database search did not identify 

any residential housing within the 0.25 mile distance. 

J-2 Appendix J. Socioeconomics
Table J2.2 Socioeconomic Information for Populations near the Proposed Game Fence Areas1

Population and Housing Units

Maverick County

Number (percentage)

Starr County

Number percentage)

Zapata County

Number (percentage)

Rosita Area El Indio Area 

Total Population 335 101 501 3,391

 Hispanic Population 298 (89%) 85 (84%) 479 (96%) 3,163 (93%)

Non-Hispanic Population 37 (11%) 16 (16%) 22 (4%) 228 (7%)

Housing Units 116 36 169 1,582

1

USCB (U.S. Census Bureau). 2007-2011. American Community Survey 5-Year Estimates. U.S. Department of Commerce website 

(http://factfinder2.census.gov/faces/nav/jsf/pages/index.xhtml) last accessed Apr. 25, 2013. 

Appendix J. Socioeconomics J-3 
United States Department of Agriculture

Animal and Plant 

Health Inspection Service

A

B

C

D

E

F

G H

I

J

K

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 9 18 27 36 4.5

Miles

Proposed Tick Control Barriers along the Tick Eradication Quarantine Line, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Chula Vista 1-5

Loma Bonita

Loma Linda #1

El Pueblo Nuevo

Riverside Acres

Las Quintas Fronterizas

Las Brisas

Loma Linda #2

Loma Linda #3

Rosita Valley

Rosita Gardens

La Herradura

Kickapoo Indian Village

Nellis Lands

Los Jardines Verdes

Eagle Heights #1

Paisano Heights

Loma Linda #5

Eagle Heights #4

Rockaway Country Sites

Loma Linda Ranchettes

Green Acres #1 & 2

Morales #3

Heritage Farm

Las Hacienditas

Loma Linda #4

Morales #2 East

Chula Vista School Block

Cedar Ridge #2

Los Guajillos Subd.

Las Carretas Subd.

Eagle Heights #3

Cedar Ridge #1

Lago Vista Subd.

Morales Circle

Morales #2 West

Victoriano Hernandez

Morales #2a

Eagle Heights #2

Zamora Lands

Border Housing Unit #1

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.350.7 1.4 2.1 2.8

Miles

A - Proposed Tick Control Barrier. Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

El Indio Townsite

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.150.3 0.6 0.9 1.2

Miles

B - Proposed Tick Control Barrier. Maverick County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Dolores

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.3 0.6 1.2 1.8 2.4

Miles

E- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

San Ygnacio

San Ignacio Viejo Unit 2

Valle Verde

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.3 0.6 1.2 1.8 2.4

Miles

F- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

San Ygnacio

San Ignacio Viejo Unit 2

Valle Verde

Ramireno

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.2 0.4 0.8 1.2 1.6

Miles

G- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Zapata Townsite

Manuel Medina Addition

Falcon Mesa

Falcon Shores

Siesta Shores Sec. A

Siesta Shores 1

Falcon Estates

Cuellar

Buena Vista

Black Bass

Flores Addition

Guzman

Siesta Shores 3

Morgan's Lakefront Lodge

Linda Vista

Lago Halcon B

Four Seasons

Lago Halcon A

Ranchito San Jose

A.F. Pierce

Las Palmas

S. Truman Phelps

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

0 0.4 0.8 1.6 2.4 3.2

Miles

H - Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

New Falcon

Lopeno

Morales / Sanchez

Los Lobos

Morales 2

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

00.4250.85 1.7 2.55 3.4

Miles

J- Proposed Tick Control Barrier. Zapata County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
United States 

Department of Agriculture

Animal and Plant 

Health Inspection Service

Lago Vista

North Escobares Ranchettes

La Minita

Salineno North

Salineno South

Fronton North

Chapeno

Los Arrieros

Roma Creek #1, 2 & 3

Falconaire

La Loma de Falcon

Fronton Ranchettes

Indio #2

Indio #1

Sunset

Ramos

Sandoval Moraida

Ramos Addition #1

J. F. Villareal

H. Cuellar Estates

Santa Margarita

Jardin de San Julian

Sources: Esri, DeLorme, NAVTEQ, USGS, Intermap, iPC, NRCAN, Esri

Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom, 2012

Date Printed: October 25, 2012 o Data Source:

TeleAtlas - roads

NAIP - imagery

USDA-APHIS-PPD-ERAS

4700 River Road, Unit 149

Riverdale, MD 20737

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service 

collected the data displayed for internal agency purposes only. These data may 

be used by others; however, they must be used for their original intended purpose.

00.4250.85 1.7 2.55 3.4

Miles

K- Proposed Tick Control Barrier. Starr County, Texas

Coordinate System: 

Teale Albers, NAD 83

Legend

Structure

Colonias

Proposed Fence

* Proposed game fencing Location is

approximate and would not obstruct access to

public/private roads or driveways.
Appendix K. Additional Historic/ Cultural Information

I. County Historical Commission Chairs contacted in 2009

Maverick County 

John Sullivan, Acting Chair 

830-773-3824 

jsullivan@maverickcounty.org

Starr County 

Sam Ramos

146 Old Sauz Road, Rio Grande, Texas 78582 

956-500-0224 

Samramos66@hotmail.com

Zapata County 

Guadalupe Pacheco

P.O. Box 10599, Zapata, Texas 78076 

956-765-3062 

II. County Historical Commission Chairs contacted in 2013

Webb County 

Elisa Gutierrez

210 West Oak Circle, Laredo, Texas 78041 

Gutierrez0265g@yahoo.com

Zapata County

Diana Brandon, P.O. Box 56, Zapata, 78076 

956-500-6088 

dbrandon227@yahoo.com

III. Summary of Historic Sites

Table K-1. Historic Sites Identified In Or Near The Area Of Potential Effects In

Each County Where Cattle-Fever Tick Fencing Is Proposed To Be Installed1 

County Name of site Relative location Summarized uses

Maverick Fort Duncan

Bounded by Monroe and 

Garrison Sts,. city limits 

on the S, and the Rio 

Grande on the W, Eagle 

Pass 

1825-1849 Military Fortification; currently 

Museum/ Park; Landscape, Recreation and 

Culture

Maverick Maverick County 

Courthouse

Public Square, Eagle 

Pass 

1875-1899 and currently Correctional Facility, 

Courthouse

Appendix K. Additional Historic/Cultural Information K-1 
Table K-1: (cont’d)

County Name of site Relative location Summarized uses

Starr Fort Ringgold 

Historic District

Rio Grande City School 

grounds, 1/4 mi. SE of jct. 

of US 83 and TX 755, Rio 

Grande City

1825-1949 Defense, Domestic, Landscape; 

currently plaza and school

Starr Guerra, Fred and 

Nell Kain House

800 Blk. W Main, Rio 

Grande City

1925-1949 Mission/Spanish revival Architecture; 

currently not in use

Starr LaBorde House, 

Store and Hotel

601 E Main St., Rio 

Grande City

1875-1924 Greek Revival / Late Victorian 

Architecture, Commerce, Trade, Domestic; 

currently hotel

Starr Mifflin Kenedy 

Warehouse and Old 

Starr County 

Courthouse

200 Blk. W Water St., Rio 

Grande

1850-1899 Commerce, Politics, Government; 

currently Government

Starr Rio Grande City 

Downtown Historic 

District

Roughly bounded by N 

Corpus, E Wimpy, N 

Avasolo and E Mirasoles, 

Rio Grande

1825-1949 Late Victorian Architecture,

Commerce, Trade, Domestic; currently not in 

use

Starr Roma Historic 

District

Properties along Estrella 

and Hidalgo Sts. between 

Garfield St. and Bravo 

Alley, Roma

1825-1924 Classical Revival Architecture; 

currently Commerce, Trade, Domestic, 

Government, Landscape, Religion, 

Transportation

Starr Roma-San Pedro 

International Bridge

SW of Hidalgo St. and 

Bravo Alley, Roma-Los 

Saenz

1925-1949 Engineering, Commerce, 

Transportation; currently Road-Related

Starr Yzaquirre--Longoria 

House

107 W Water St., Rio 

Grande

1850-1974 Architecture, Engineering, Domestic 

Dwelling; currently not in use

Starr de la Pena, Silverio, 

Drugstore and Post 

Office

423 E Main St., Rio 

Grande City

1875-1924 Architecture, Engineering, 

Commerce, Trade, Government; currently 

Commerce, Trade, Domestic

Webb All historic sites are more than 20 miles from the areas proposed for game fencing. The list of these 

sites is in the Administrative Record.

Zapata Dolores Nuevo Address restricted 1850-1874 Hispano-Mexican Exploration / 

Settlement; currently Agriculture, Subsistence

Zapata Dolores Viejo Address restricted 1750-1799 Spanish Exploration / Settlement, 

Architecture; currently Landscape

Zapata San Francisco 

Ranch

1 mi. N of San Ygnacio, 

San Ygnacio

1875-1899 Agriculture / Subsistence, Domestic; 

currently Agricultural Fields

Zapata Corralitos Ranch

(within CFTPZ but 

not near the fence?)

2 mi. N of San Ygnacio off 

U.S. 83, San Ygnacio 

1950-1899 Hispano-Mexican Agriculture / 

Subsistence, Domestic; currently in other uses

Zapata San Ygnacio Historic 

District

Town of San Ygnacio 1825-1900 Architecture / Engineering Domestic 

Dwelling; currently Domestic Dwelling

Zapata Trevino--Uribe 

Rancho

Jct. of Uribe and Trevino 

Sts., San Ygnacio

1825-1949 Domestic Dwelling; currently not in 

use

1 Information derived by combining search results from the National Register of Historic Places (http://www.nps.gov) 

and the Atlas database on the Texas Historical Commission website (http://www.thc.state.tx.us/) with ARC GIS

mapping of the proposed fence locations.

IV. Tribes Contacted in 2009 and 2013

Tonkawa Tribe of Indians of Oklahoma 

Don L. Patterson, President 

1 Rush Buffalo Road 

Tonkawa, Oklahoma 74653 

580-628-2561 

K-2 Appendix K. Additional Historic/Cultural Information