United States Department of Agriculture / Forest Service

Rocky Mountain Research Station

General Technical Report RMRS-GTR-304

August 2013

The Southern Nevada Agency Partnership 

Science and Research Synthesis:

Science to Support Land Management in Southern Nevada

Executive Summary
You may order additional copies of this publication by sending your 

mailing information in label form through one of the following media. 

Please specify the publication title and number.

Publishing Services

Telephone (970) 498-1392

FAX (970) 498-1122

E-mail rschneider@fs.fed.us

Web site http://www.fs.fed.us/rmrs

Mailing Address Publications Distribution

Rocky Mountain Research Station

240 West Prospect Road

Fort Collins, CO 80526

Chambers, Jeanne C.; Brooks, Matthew L.; Pendleton, Burton K.; Raish, Carol B., eds. 2013. The 

Southern Nevada Agency Partnership Science and Research Synthesis: Science to support land management in Southern Nevada Executive Summary. Gen. Tech. Rep. RMRSGTR-304. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station. 79 p.

Abstract

This synthesis provides information related to the Southern Nevada Agency Partnership (SNAP) 

Science and Research Strategy Goal 1 – to restore, sustain and enhance southern Nevada’s ecosystems – and Goal 2 – to provide for responsible use of southern Nevada’s lands in a manner that 

preserves heritage resources and promotes an understanding of human interaction with the landscape. The Science and Research Strategy has nine Sub-goals that address the topics of water and 

water use, fire, invasive species, biological diversity, restoration, cultural resources, historic content, 

recreation, and science-based management. This synthesis summarizes the state-of-knowledge 

related to each of these Sub-goals, addresses knowledge gaps, and provides management implications. It builds on previous efforts to develop the necessary scientific understanding for adaptive 

management of southern Nevada ecosystems.

Keywords: Mojave, Great Basin, anthropogenic disturbance, climate change, invasive species, 

altered fire regimes, water resources, species of conservation concern, restoration, 

heritage resources, recreation, ecosystem resilience, science-based management

Editors

Jeanne C. Chambers is a Research Ecologist with the U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station in Reno, Nevada, and an Adjunct Professor at the University of Nevada, Reno. Her research focuses 

on the restoration of disturbed or degraded upland and riparian ecosystems in the western United States. Since 1992, 

much of her work has been on understanding disturbance processes in the arid Great Basin and developing concepts 

and methods for maintaining or restoring ecosystem resilience.

Matthew L. Brooks is a Research Botanist with the Department of the Interior, U.S. Geological Survey, Western 

Ecological Research Center, Yosemite Field Station in Oakhurst, California. His primary research interest is the 

ecology and management of invasive species and wildfire in western North America. He has studied Mojave Desert 

ecosystems and evaluated effects of land use practices in that region since 1988.

Burton K. Pendleton is a Research Ecologist with the U.S. Department of Agriculture, Forest Service, Rocky Mountain 

Research Station in Albuquerque, New Mexico. His primary research interest is the ecology of desert shrub communities, with an emphasis on the blackbrush community. He is co-leader of the Comprehensive Inventory and Monitoring 

Project for the Spring Mountains National Recreation Area, Humboldt-Toiyabe National Forest from 2010-2013. 

Carol B. Raish is a Research Social Scientist with the U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station in Albuquerque, New Mexico. Her primary research interests include examining resource use 

on public land and exploring the role of traditional economic practices, such as small-scale ranching, in maintaining 

cultural heritage. Other projects have included working with communities to understand their preferences concerning 

fire and fuels management on public land.
Authors

Wayne R. Belcher

U.S. Geological Survey

Nevada Water Science Center

Henderson, NV 89074

wbelcher@usgs.gov

Matthew L. Brooks

U.S. Geological Survey

Western Ecological Research Center

Yosemite Field Station

Oakhurst, CA 93644

matt_brooks@usgs.gov

Jeanne C. Chambers

U.S. Department of Agriculture, Forest Service

Rocky Mountain Research Station

Reno, Nevada 89512

jchambers@fs.fed.us

Steven M. Ostoja

U.S. Geological Survey

Western Ecological Research Center

Yosemite Field Station

Oakhurst, CA 93644

sostoja@usgs.gov

Randy A. McKinley

U.S. Geological Survey

Earth Resources Observation and Science Center

Sioux Falls, SD 57198-0001

rmckinley@usgs.gov

Alice M. McSweeney

U.S. Department of Agriculture, Forest Service

Rocky Mountain Research Station

Albuquerque, NM 87102-3497

Current Address:

Box 24

Glorietta, NM 87535

amcsweeney@cybermesa.com

Acknowledgments

Financial and technical support for this project was provided by the Southern Nevada Agency Partnership. Additional support was provided by the U.S. Geological Survey, Terrestrial, Fresh Water, and Marine 

Ecosystems and Invasive Species Programs, and the U.S. Forest Service, Rocky Mountain Research 

Station, Grasslands Shrublands and Deserts Program. Review comments were provided by: Mark C. 

Slaughter (Bureau of Reclamation); Lauren Brown, Fred Edwards, Krystal Johnson, Sean McEldery, 

Marilyn Peterson and Boris Poff (Bureau of Land Management); Jill Craig and Ashley Fisher (Great Basin 

Institute); Steve Daron, Curt Deuser, Jim Holland, Eva Jensen, Gary Karst, Sky McCain, Alice Newton 

and Deborah Reardon (National Park Service); Derek Hall (National Security Technologies); Edith B. 

Allen (University of California, Riverside); Scott R. Abella (University of Nevada, Las Vegas); Kent Ostler 

(U.S. Department of Energy); Matt Flores, Darrell Freeman, Glenn Gibson, Johnny Jones, Mark (Tim) 

Rash, James M. Roberts, and Angelina Yost (U.S. Fish and Wildlife Service); Marisa Anderson, Richard 

Periman, Andrew Tanner, and Kelly Turner (U.S. Forest Service); Stan Kitchen (U.S. Forest Service, 

Rocky Mountain Research Station); Sue Jones, Phil Medica, A. Keith Miles, and Tom Suchanek (U.S. 

Geological Survey). Special thanks to the Southern Nevada Agency Partnership Science and Research 

Team for both guidance and manuscript review: Gordon Olsen (National Park Service), Brian Novosak 

and Laurie Simons (U.S. Fish and Wildlife Service); James Hurja (U.S. Forest Service); and especially 

Carolyn J. Ronning (Bureau of Land Management) and Kent Turner (National Park Service).

Michael J. Moran

U.S. Geological Survey

Nevada Water Science Center

Henderson, NV 89074

mjmoran@usgs.gov

Burton K. Pendleton

U.S. Department of Agriculture, Forest Service

Rocky Mountain Research Station

Albuquerque, NM 87102-3497

bpendleton01@fs.fed.us

Carol B. Raish

U.S. Department of Agriculture, Forest Service

Rocky Mountain Research Station

Albuquerque, NM 87102-3497

craish@fs.fed.us 

Megan E. Rogers 

U.S. Geological Survey

Nevada Water Science Center

Henderson, NV 89074

mrogers@usgs.gov

Donald W. Sada,

Desert Research Institute

Division of Hydrologic Sciences

Reno, NV 89509

don.sada@dri.edu

Kent Turner

National Park Service

Lake Mead National Recreation Area

Boulder City, NV 89005

kent_turner@nps.gov

Contents

1. An Overview of the Southern Nevada Agency Partnership Science and 

Research Synthesis .................................................................................................1

Jeanne C. Chambers, Matthew L. Brooks, Kent Turner,

Carol B. Raish, and Steven M. Ostoja

Executive Summary.................................................................................................................1

Science and Research Strategy ..............................................................................................1

Science and Research Synthesis Report ................................................................................4

Science-based Management ...................................................................................................6

Key References .......................................................................................................................6

2. Ecosystem Stressors in Southern Nevada ...............................................................9

Burton K. Pendleton, Jeanne C. Chambers, Matthew L. Brooks, and Steven M. Ostoja

Executive Summary.................................................................................................................9

Global Stressors ......................................................................................................................9

Local and Regional Stressors..................................................................................................9

Knowledge Gaps and Management Implications...................................................................12

Key References .....................................................................................................................12

3. Water and Water Use in Southern Nevada..............................................................15

Wayne R. Belcher, Michael J. Moran, and Megan E. Rogers

Executive Summary...............................................................................................................15

Ground Water.........................................................................................................................15

Surface Water........................................................................................................................16

Knowledge Gaps and Management Implications...................................................................17

Key References .....................................................................................................................17

4. Invasive Species in Southern Nevada.....................................................................19

Matthew L. Brooks, Steven M. Ostoja, and Jeanne C. Chambers

Executive Summary...............................................................................................................19

Invasive Plants.......................................................................................................................19

Invasive animals ....................................................................................................................21

Knowledge Gaps and Management Implications...................................................................22

Key References .....................................................................................................................24
5. Fire History, Effects, and Management in Southern Nevada.................................25

Matthew L. Brooks, Jeanne C. Chambers, and Randy A. McKinley

Executive Summary...............................................................................................................25

Fire History and Patterns of Burning......................................................................................25

Fire Effects and Management Actions ...................................................................................29

Knowledge Gaps and Management Implications...................................................................33

Key References .....................................................................................................................33

6. Species of Conservation Concern and Environmental Stressors: Local, Regional 

and Global Effects ..................................................................................................35

Steven M. Ostoja, Matthew L. Brooks, Jeanne C. Chambers, and 

Burton K. Pendleton

Executive Summary...............................................................................................................35

Alpine and Bristlecone Pine Ecosystems...............................................................................35

Mixed Conifer Ecosystem ......................................................................................................35

Piñon-Juniper Ecosystem ......................................................................................................36

Sagebrush Ecosystem...........................................................................................................36

Blackbrush/Shadscale Ecosystem.........................................................................................37

Mojave Desert Scrub Ecosystem...........................................................................................37

Riparian/Aquatic Ecosystem..................................................................................................37

Spring Ecosystems ................................................................................................................38

Knowledge Gaps, Research Guidance,

and Management Implications..........................................................................................38

Key References .....................................................................................................................39

7. Maintaining and Restoring Sustainable Ecosystems in Southern Nevada .........41

Jeanne C. Chambers, Burton K. Pendleton, Donald W. Sada, 

Steven M. Ostoja, and Matthew L. Brooks

Executive Summary...............................................................................................................41

Managing for Resilience and Resistance...............................................................................41

Restoration Considerations....................................................................................................42

Knowledge Gaps....................................................................................................................46

Management Implications......................................................................................................47

Key References .....................................................................................................................49

8. Human Interactions With the Environment Through Time 

in Southern Nevada................................................................................................51

Carol B. Raish

Executive Summary...............................................................................................................51

Focal Area..............................................................................................................................51

Culture History .......................................................................................................................51

European Contact..................................................................................................................56

Knowledge Gaps and Management Implications...................................................................57

Key References .....................................................................................................................58
9. Preserving Heritage Resources Through Responsible Use of 

Southern Nevada’s Lands......................................................................................61

Carol B. Raish

Executive Summary...............................................................................................................61

Cultural Resources at Risk ....................................................................................................61

Cultural Resource Protection Measures and Organizations..................................................61

Non-Destructive Techniques for Identification of Archeological and Historic Remains ..........63

Knowledge Gaps and Management Implications...................................................................63

Key References .....................................................................................................................64

10. Recreation Use on Federal Lands in Southern Nevada.......................................67

Alice M. McSweeney

Executive Summary...............................................................................................................67

Outdoor Recreation Issues ....................................................................................................67

Snap Interagency Recreation and Wilderness Planning........................................................67

Regional Trail Planning and Outreach ...................................................................................68

Knowledge Gaps and Management Implications...................................................................68

Key References .....................................................................................................................69

11. Science-Based Management of Public Lands in Southern Nevada....................71

Matthew L. Brooks and Jeanne C. Chambers

Executive Summary...............................................................................................................71

Current Scientific Understanding and Information Needs......................................................72

The Role of Science in Land Management............................................................................76

The Role of Science in Education..........................................................................................77

Key References .....................................................................................................................77

USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 1

Chapter 1

An Overview of the Southern Nevada Agency 

Partnership Science and Research Synthesis

Jeanne C. Chambers, Matthew L. Brooks, Kent Turner,

Carol B. Raish, and Steven M. Ostoja

Executive Summary

Maintaining and restoring the diverse ecosystems and resources that occur in southern 

Nevada in the face of rapid socio-economic and ecological change presents numerous 

challenges to Federal land managers. Rapid population growth since the1980s, the land 

uses associated with that growth, and the interactions of those uses with the generally 

dry and highly variable climate result in numerous stresses to ecosystems, species, and 

cultural resources. In addition, climate models predict that the rate of temperature increase and, thus, changes in ecological processes, will be highest for ecosystems like the 

Mojave Desert. The Southern Nevada Agency Partnership (SNAP; http://www.SNAP.

gov) was established in 1999 to address common issues pertaining to public lands in 

southern Nevada. Partners include the Bureau of Land Management, National Park 

Service, U.S. Fish and Wildlife Service, and USDA Forest Service and they work with 

each other, the local community, and other partners. SNAP agencies manage more than 

seven million acres of public lands in southern Nevada (95% of the land area). Federal 

land includes two national recreation areas, two national conservation areas, four national wildlife refuges, 18 congressionally designated wilderness areas, five wilderness 

study areas, and 22 areas of critical environmental concern. The partnership’s activities 

are mainly centered in Southern Nevada’s Clark County (fig. 1.1), but lands managed 

by SNAP partner agencies also include portions of the Lake Mead National Recreation 

Area in Mohave County, Arizona, U.S. Fish and Wildlife Service, and USDA Forest 

Service-managed lands in Lincoln and Nye Counties, Nevada, and all lands and activities 

managed by the Southern Nevada District Office of the Bureau of Land Management. 

These lands encompass nine distinct ecosystem types (fig. 1.2), support multiple species of management concern and 17 listed species, and are rich in cultural and historic 

resources. This introductory executive summary discusses the Science and Research 

Strategy developed by the SNAP agencies, the Science and Research Report, and need 

for science-based management in southern Nevada.

Science and Research Strategy

The SNAP agencies are interested in developing an interagency science program that 

is consistent across agency boundaries and that can inform management decisions regarding natural resources, cultural resources, and human use of public lands. A science and 

research team was established by the SNAP agencies to develop the interagency science 

program. This team published the SNAP Science and Research Strategy (Strategy) in 

2009. The Strategy is designed to integrate and coordinate scientific research programs 

in southern Nevada and to improve the efficiency and effectiveness of these programs. 
2 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Figure 1.1—Map of the SNAP area illustrating land ownership within the region. 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 3

Figure 1.2—Map of the SNAP area illustrating the southern Nevada ecosystem types recognized in the 

Clark County MSHCP.
4 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

The Strategy’s purpose is to inform and guide SNAP agencies in identifying the highest 

priority science and research needs, sharing resources and funds to implement needed 

research, communicating research needs to potential research partners, and eliminating 

redundancy between agency research programs.

Key components of the Strategy are an annual SNAP science needs assessment and 

a SNAP Science and Research Synthesis Report (Synthesis Report). The needs assessment is used to communicate SNAP’s science and research needs to the broader scientific research community and to potential research partners. It documents high priority 

regional and management needs, is prepared by the SNAP science and research team, 

and is based on input of agency managers, resource staff, and scientists. The Synthesis Report summarizes the state of knowledge and key science findings related to the 

SNAP Science and Research Strategy Goals, identifies knowledge gaps, and provides 

management implications. The Synthesis Report is prepared on a 5-year basis and is 

used to guide the annual SNAP science needs assessments. The first Synthesis Report is 

comprised of two General Technical Reports; one that has chapters with detailed reviews 

and one that includes these Executive Summaries of the more detailed chapters.

The SNAP Science and Research Strategy established several Goals for interagency 

science and research that is conducted in support of resource management in southern 

Nevada. Development of the Goals was based on individual agency goals, the SNAP 

Board vision, the interagency science and research team’s charter goals, the input of 

individual agency specialists, and input from interdisciplinary scientists that was obtained 

during several planning workshops. Each Goal has a set of Sub-goals and questions that 

address specific science needs. The three main Goals are:

Goal 1. Restore, sustain, and enhance Southern Nevada’s ecosystems.

Goal 2. Provide for responsible use of Southern Nevada’s lands in a manner that 

preserves heritage resources and promotes an understanding of human 

interaction with the landscape.

Goal 3. Promote scientifically informed and integrated approaches to effective, 

efficient, and adaptive management.

Science and Research Synthesis Report

The Goals and Sub-goals of the SNAP Science and Research Strategy provide key 

focal areas for both the annual science needs assessments and the science and research 

Synthesis Report. This Synthesis Report addresses information related to Goals 1 and 

2 and their associated Sub-goals (table 1.1). The Sub-goals address the topics of fire, 

invasive species, landscapes and watersheds, biological diversity, cultural resources, 

historic content, recreation, land uses, and education. This Synthesis Report provides 

a summary of the state of knowledge related to each of the nine Sub-goals, addresses 

knowledge gaps, and provides management implications. It builds on previous efforts to develop the necessary scientific understanding for adaptive management of 

southern Nevada ecosystems including the Multi Species Habitat Conservation Plan 

(MSHCP), and a 2007 workshop that was organized by the Desert Research Institute on 

the characteristics of southern Nevada ecosystems and the threats to ecosystem health. 

The Synthesis Report is organized around the topics addressed in the Sub-goals, and 

table 1.1 provides a crosswalk between the chapters in this document and the Goals and 

Sub-goals in the SNAP Strategy.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 5

Table 1.1—A crosswalk relating the chapters in this document to the Goals and Sub-goals in the SNAP Science and Research Strategy.

Goal/Chapter Sub-goal

Goal 1. Restore, sustain, and 

enhance southern Nevada’s ecosystems

Chapter 1. An Overview of the Southern 

Nevada Agency Partnership Science and 

Research Synthesis 

Chapter 2. Southern Nevada Ecosystem Stressors 

Chapter 3. Water and Water Use in Sub-Goal 1.3. Restore and sustain proper

Southern Nevada function of southern Nevada’s watersheds

and landscapes

Chapter 4. Invasive Species in Southern Nevada Sub-Goal 1.2. Protect southern Nevada’s

ecosystems from the adverse impacts of 

invasive species

Chapter 5. Fire History, Effects, and Sub-Goal 1.1. Manage wildland fire to

Management in Southern Nevada sustain southern Nevada’s ecosystems

Chapter 6. Species of Conservation Concern Sub-Goal 1.4. Sustain and enhance southern

and Environmental Stressors: Nevada’s biotic communities to preserve

Local, Regional, and Global Effects biodiversity and maintain viable populations

Chapter 7. Maintaining and Restoring, Sub-Goal 1.3. Restore and sustain proper

Sustainable Ecosystems in Southern Nevada function of southern Nevada’s watersheds

 and landscapes

Goal 2. Provide for responsible use of southern 

Nevada’s lands in a manner that preserves

heritage resources and promotes an understanding 

of human interaction with the landscape

Chapter 8. Human Interactions with the Sub-Goal 2.1. Develop an understanding of 

Environment through Time in Southern human interactions with the environment

Nevada through time

Chapter 9. Preserving Heritage Resources Sub-Goal 2.2. Preserve heritage resources

through Responsible Use of through responsible use of southern 

Southern Nevada’s Lands Nevada’s lands

Chapter 10. Recreation Use on Federal Lands Sub-Goal 2.4. Provide for appropriate 

in Southern Nevada (type and location), quality, and diverse

 recreational experiences, resulting in 

responsible visitor use on federal lands in

 southern Nevada

Chapter 11. Science-based Management of Sub-Goal 2.3. Manage current and future

Public Lands in Southern Nevada authorized southern Nevada land uses in a

manner that balances public need and 

ecosystem sustainability

Sub-Goal 2.5. Promote an effective 

conservation education and interpretation 

program to improve the quality of resources

and enhance public use and enjoyment of

southern Nevada public lands
6 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Science-Based Management

Science-based management aimed at maintaining sustainable ecosystems is essential 

if public lands in southern Nevada are to continue to support both multiple land uses 

and habitat for the region’s diverse assemblage of plants and animals. Sustainable or 

“healthy” ecosystems exhibit resilience to stressors and disturbances and resistance to 

invasives and supply important ecological services and goods. Due to the strong elevation/climate gradients in the region and the large differences in the abiotic and biotic 

characteristics of southern Nevada ecosystems, the different ecosystem types exhibit 

varying levels of ecological resilience. In general, ecosystems that receive the highest 

levels of precipitation or that are the most productive are the most resilient to stressors 

and disturbances in the Great Basin and Mojave deserts. For example, among the least 

resilient are Mojave Desert scrub ecosystems at low elevations and alpine ecosystems 

at high elevations, while the most resilient are mixed conifer and piñon and juniper 

ecosystems. In contrast, resistance to invasives tends to be higher in the most stressful 

environments (salt desert shrub and alpine ecosystems) because only a limited suite of 

species are adapted to establish and persist under the harsh conditions. Several interacting 

factors influence both resilience to disturbance and stressors and resistance to invasives 

in arid and semi-arid ecosystems including the climatic regime and other environmental 

characteristics of the ecosystem, its ecological condition, the severity and frequency of 

disturbance, and feedbacks among invasive species and disturbance regimes.

Adaptive management that is aimed at maintaining or increasing resistance and resilience can reduce the uncertainty associated with management decisions and increase 

the region’s capacity to deal with stressors without losing options for the future. Key 

aspects of adaptive management are a scientific understanding of the underlying processes structuring southern Nevada ecosystems, the effects of the numerous stressors 

on these ecosystems and their associated species, and the factors that influence their 

ecological resistance and resilience. Routine assessment of the ecological conditions of 

the different ecosystem types and monitoring the effects of the region’s stressors and of 

management actions to maintain or restore ecosystem resistance and resilience provides 

feedback for adaptive management. Periodic science syntheses, like the ones in this 

GTR, give information on the current state of knowledge and the ecological trajectories 

of the region’s ecosystems and species, and identify needed information for effective 

management.

For a complete discussion of topics in this executive summary, see Chapter 1, An 

Overview of the Southern Nevada Agency Partnership Science and Research Synthesis, 

in “The Southern Nevada Agency Partnership Science and Research Synthesis—Science 

to Support Land Management in Southern Nevada” (RMRS GTR-303).

Key References

Brooks, M.L.; Chambers, J.C. 2011. Invasive plants and altered fire regimes in the deserts of North 

America. Rangeland Ecology and Management. 64:431–438. doi: 10.2111/REM-D-09-00165.1.

Chapin, F.S., III.; Torn, S.E.; Tateno, M. 1996. Principles of ecosystem sustainability. The American Naturalist. 148: 1016-1037.

Desert Research Institute. 2008. Task 7: First iteration conceptual models for 11 MSHCP ecosystems. Annual Report. Project 2005-DRI-574A-P. Reno, NV: Desert Research Institute.

Fenstermaker, L.F.; McDonald, E.V.; Webb, R.H. 2009. Regional threats to the Mojave Desert. In: Webb, 

R.H.; Fenstermaker, L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, E.V; Miller, D.M., eds. The Mojave 

Desert: Ecosystem processes and sustainability. Las Vegas, NV: University of Nevada Press: 7-10.

Folke, C.; Carpenter, S.; Elmqvist, T.; [and others]. 2002. Resilience and sustainable development: Building adaptive capacity in a world of transformations. Scientific background paper on resilience for the 

process of The World summit on sustainable development on behalf of The Environmental Advisory 

Council to the Swedish Government. Stolkholm, Sweden: Ministry of the Environment. 74 p.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 7

Loarie, S.R.; Duffy, P.B.; Hamilton, H.; Asner, G.P.; Field, C.B.; Ackerly, D.D. 2009. The velocity of 

climate change. Nature. 462: 1052-1055.

RECON (Regional Environmental Consultants, Inc.). 2000. Final Clark County Nevada multiple species 

habitat conservation plan and environmental impact statement. Prepared for Clark County Administrative Services. 550 p. plus appendices.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

U.S. Environmental Protection Agency. 2010. Ecoregions of Nevada. Western Ecology Center. Online: 

http://www.epa.gov/wed/pages/ecoregions/nv_eco.htm#Ecoregions. [2011, 5 April].
8 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 9

Chapter 2

Ecosystem Stressors in Southern Nevada

Burton K. Pendleton, Jeanne C. Chambers, Matthew L. Brooks, and 

Steven M. Ostoja

Executive Summary

Southern Nevada ecosystems are subject to a number of stressors that range in scope 

from local to regional to global. At the regional scale, human population growth and 

related activities constitute a major stressor. Nevada has undergone significant change 

due to unprecedented population growth and ongoing global change processes. Nevada’s 

growth rate has been the highest in the nation for the last five decades. Clark County 

has experienced particularly rapid growth with a population increase of more than 40 

percent since the 2000 census. Other regional or local stressors, many of which are 

related to human population growth, include invasive species, changes in land use, and 

altered fire regimes. Global stressors affecting southern Nevada ecosystems include 

elevated carbon dioxide (CO2) concentrations, nitrogen (N) deposition, and changes in 

temperature and precipitation patterns. This chapter provides background information 

on the stressors affecting southern Nevada’s ecosystems that is needed to address Goal 

1.0 in the SNAP Science Research Strategy, which is “Restore, sustain, and enhance 

southern Nevada’s ecosystems.”

Global Stressors

Atmospheric CO2 increased approximately 32 percent during the last century and is 

expected to double by the end of this century. Concentrations of CO2 are closely linked 

to global warming and climate change. Over the last 150 years, global temperatures have 

risen in tandem with increasing CO2. Data for Nevada show that temperatures have risen 

2.0 °C since 1908, with a projected increase of 2-6 °C by 2100. Increases in nighttime 

temperatures will likely lead to an expansion of desert species northward. Precipitation 

patterns also are influenced by rising levels of atmospheric CO2 through changes in 

ocean temperatures and global circulation patterns. In addition to expected changes in 

the amount and timing of precipitation, rising temperatures will likely decrease snow 

pack levels and increase the rate of snow-melt, resulting in lower mid-summer stream 

flows. Longer and more intense droughts are expected to occur throughout the west. 

Drought and reduced runoff will result in increased competition for the limited water 

resources of southern Nevada.

Local and Regional Stressors

Population Growth and Urbanization

Until the recent economic downturn, Nevada was the fastest growing state in the 

country for five straight decades. The vast majority of urban development has taken 

place in the Mojave Desert scrub ecosystem. Associated issues include dust generation, 
10 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

dumping, off-road travel and unauthorized roads, destruction of cultural resources, 

creation of dispersal corridors for exotic species, and land degradation caused by uncontrolled recreation and ORV use. Vegetation communities at higher elevations are 

impacted by recreational activities of the large urban population. Pollution and dust from 

energy development, housing development, and recreation affect air quality through 

increases in airborne particulate matter. Of particular concern are particles smaller than 

10 micrometers in diameter (PM-10), which can cause serious health effects. Windblown 

dust accounts for 89-90 percent of the PM-10 occurring in Clark County.

Control measures currently being implemented are expected to offset increases in 

vehicular emissions that accompany population growth.

Nitrogen Deposition

Industrial and urban pollution have led to increased levels of atmospheric nitrogen 

deposition. Nitrogen deposition generally occurs as dust. Increased levels of nitrogen 

may result in higher biomass production if accompanied by sufficient moisture; however, potential gains in productivity will likely be mitigated by changes in climate. 

Unfortunately, exotic annual grasses are particularly responsive to increased levels of 

nitrogen, potentially causing a community shift from shrubland to one dominated by 

invasive grasses. Increased levels of soil N are also expected to alter nutrient cycling.

Energy Development

In southern Nevada, renewable energy is in the form of solar and wind energy development. The BLM has identified five solar energy zones in southern Nevada. These areas 

have high solar radiation and limited environmental concerns. Solar energy facilities 

are planned, under construction, or in operation in Boulder City and Amargosa Valley. 

Limited experience with large-scale solar facilities means that there is little on-the-ground 

capacity to mitigate potential impacts. Attention during the planning, construction and 

operation phases could help to minimize potential environmental impacts.

The technology to develop energy from wind on a large scale is more mature than 

that for large-scale solar development, but our understanding of potential impacts of 

proposed large-scale wind farms in southern Nevada is severely lacking. Potential effects 

of wind turbines on wildlife include avoidance behavior, and bird and bat mortality.

Recreation

As the population in southern Nevada continues to grow, so too will the use of public lands for recreation. Meeting recreational needs of both citizens and visitors to the 

area must be balanced with maintaining natural resources and conserving the unique 

biodiversity of southern Nevada’s ecosystems.

Water Development

Water is a very critical issue throughout the Southwest. The Southern Nevada Water Authority (SNWA) was formed in 1991 with the goal of managing existing water 

resources, developing new ones, and promoting conservation. Ninety percent of the 

water provided by the Las Vegas Valley Water District is from Colorado River water 

impounded in Lake Mead. Ten percent of the water budget comes from approximately 

100 municipal groundwater wells. Based on current and projected demands, a longterm water supply other than the Colorado River is needed. The Water Resource Plan 

projects the need for additional groundwater resources to be brought on-line by 2020. 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 11

Springs are home for many rare species and the presence of non-native species, both 

animal and plant, constitute a major stressor. Stressors on springs include animal and 

human trampling, water diversion and groundwater pumping, seasonal freezing and 

drying, contamination, and scouring by flooding. 

Insects and Disease

Insect and disease issues in southern Nevada are limited at present. Chronic wasting 

disease in deer, white nose syndrome in bats, and respiratory infections in desert bighorn 

sheep have the potential to occur in southern Nevada, but are not currently found within 

the state. In 2009, the Humboldt-Toiyabe National Forest conducted an aerial survey 

of bark beetle damage. Over 200,000 acres were surveyed, with only minimal damage 

observed. Drought, warmer winter temperatures, and changes in precipitation amount 

and timing will certainly affect the type and extent of insect and disease outbreaks, but 

what these might be is currently unknown.

Grazing

Permitted grazing by domestic livestock in southern Nevada is minimal, although 

trespass grazing is an issue in some areas. There is a legacy of effects from grazing of 

large numbers of cattle and sheep in previous decades. Very few records of past use 

are available and that makes determining the amount of disturbance and recovery rates 

difficult. Currently, the major grazing impacts in southern Nevada come from wild 

horses and burros. The annual population increase since 2006 is estimated to be 17 to 

20 percent for wild horses and 20 percent for burros, a fact that makes maintenance 

of appropriate population size difficult. Wild horses and burros consume herbaceous 

vegetation and some parts of woody vegetation in a wide variety of vegetation types, 

with use concentrating at springs/seeps. Ground disturbance caused by trampling, particularly in areas surrounding sensitive springs and seeps, creates conditions favorable 

for invasive non-native species and may harm rare species. Large scale fires, which are 

a fairly recent phenomenon, and the projected increases in temperature and drought 

frequency will reduce available water and forage.

Invasive Species

Invasive species present a number of management issues. In the Mojave Desert, 

management of invasive plants and management of fire must be integrated due to the 

linkage between the two issues. Invasive plants produce biomass and fine fuels that 

will carry fire in the interspaces between shrubs, resulting in large, relatively frequent 

wildfires in desert shrub ecosystems that are not fire adapted. Wetland and aquatic invasives are also on the rise. Riparian weeds reduce the biodiversity of critical wetland 

communities. Also, the release of nonnative fish into springs, quagga mussels into lakes, 

and nonnative bullfrogs and crayfish into lakes and rivers are impacting the native and 

endemic fish, amphibians, and snail species. 

Altered Fire Regimes

Wildfire is a growing concern to managers in southern Nevada. The shrub communities of the Mojave Desert are not adapted to large-scale fire. Shrub seedbanks of many 

species are not sufficient for natural regeneration to occur after fire. The post-fire shrub 

community is less diverse, and has increased fine fuel loads that are prone to more 

frequent fire. Thus, the fire cycle is reset outside of the timeframe under which these 
12 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

communities developed. Restoration of the post-fire landscape is problematic due to 

lack of predictable moisture, unavailability of native seed, and other issues. Suppression 

of naturally occurring fires at upper-elevation ecosystems that are fire-adapted has also 

created a problem for land managers.

Knowledge Gaps and Management Implications

Southern Nevada is experiencing both a novel suite of stressors and an unprecedented 

rate of climate change. With the introduction of new stressors, rapid climate change, 

and increased and larger disturbances, ecosystems will change in new and difficult to 

predict directions. Managers are faced with situations for which we have no current 

answers. What can be done to control the influx of invasive species? How can we 

manage the increasing frequency and intensity of wildfires? Of particular concern are 

endemic species that exhibit specific habitat requirements. Are they resilient enough, 

genetically variable enough, or are their specialized habitats protected enough for them 

to persist in place? These questions constitute some of the big issues facing managers 

and provide a general overview of knowledge gaps, which are discussed in more detail 

in subsequent chapters. Additional information needs are:

	 •	 Species-specific climate profiles and projected ranges under different climate

change scenarios; methods to detect geographic shifts in plant communities 

and individual species.

	 •	 Effects of drought, warmer winter temperatures, and changes in precipitation

amount and timing on the type and extent of insect and disease outbreaks.

	 •	 Interactive effects ofnaturally occurringdisturbanceswithglobal changedrivers

such as rising levels of CO2 and N deposition. 

	 •	 Effects of N deposition and increased CO2 levels on biogeochemical cycles 

including biological soil crust function.

	 •	 Appropriate plant materials and planting techniques for use in reclamation and

restoration of disturbed sites under expected climate change scenarios.

	 •	 Criteria for selecting the most appropriate and least deleterious sites for energy

development.

	 •	 Information on the environmental impacts of large-scale power development,

including wind and solar, on animal mortality, migration corridors, seed movement, and potential off-site effects of dust and chemical dust control agents.

	 •	 Improved techniques for tracking available forage given the increase in the

biomass of exotic annual grasses and the accompanying changes in the size 

and frequency of wildfires. 

Human caused stressors can be mitigated through educational programs. Dust control and reduction, energy savings to reduce energy sprawl, reduction of soil surface 

disturbance, and reduction of the impact of recreational activities are among many 

areas in which existing and new educational programs could reduce human impacts. 

All educational programs should stress how these steps increase ecosystem integrity. 

For a complete discussion of topics in this executive summary, see Chapter 2, Southern 

Nevada Ecosystem Stressors in “The Southern Nevada Agency Partnership Science 

and Research Synthesis – Science to Support Land Management in Southern Nevada” 

(RMRS GTR-303).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 13

Key References

Abella, S.R. 2008. A systematic review of wild burro grazing effects on Mojave Desert Vegetation, USA. 

Environmental Management. 41:809-19.

Abella, S.R.; Newton, A.C. 2009. A systematic review of species performance and treatment effectiveness 

for revegetation in the Mojave Desert, USA. In: Bernal-Fernancez, A.; De La Rose, M.S. (eds.). Arid 

Environments and Wind Erosion. Hauppauge, NY: Nova Science Publishers, Inc.: 45-74. 

Beever, E.A.; Tausch, R.J.; Brussard, P.F. 2003. Characterizing grazing disturbance in semiarid ecosystems across broad scales, using diverse indices. Ecological Applications. 13:119-136.

Belnap, J.; Lange, O.L. (eds.). 2003. Biological soil crusts: structure, function, and management. Heidelberg: Springer-Verlag. 503 p.

Brooks, M.L.; Chambers, J.C. 2011. Resistance to invasion and resilience to fire in desert shrublands of 

North America. Rangeland Ecology and Management. 64:431-438.

Cohen, M.J. 2011. Municipal deliveries of Colorado River Basin Water. Oakland, CA: Pacific Institute. 

63 p.

ENTRIX, Inc. 2008. Spring Mountains National Recreation Area landscape analysis. Report to USDA 

Forest Service, Humboldt-Toiyabe National Forest, Las Vegas, NV. 673 p.

Grayson, D.K. 1993. The desert’s past: a natural prehistory of the Great Basin. Washington, DC: Smithsonian Institution Press. 356 p.

Holland, J.: Peterson, M.: Reardon, D.; Tanner, A.; White, E.; Yost, A. 2010. Understanding visitors to 

public lands in Clark County, Nevada. Southern Nevada Agency Partnership Recreation Team. Southern Nevada Visitor Use Monitoring. On file at: U.S. Department of Agriculture, Forest Service, Rocky 

Mountain Research Station, Albuquerque, NM. 4 p.

Loarie, S.R.; Duffy, P.B.; Hamilton, H.; Asner, G.P.; Field, C.B.; Ackerly, D.D. 2009. The velocity of 

climate change. Nature. 462:24-31.

McDonald, R.I.; Fargione, J.; Kiesecker, J.; Miller, W.M.; Powell, J. 2009. Energy sprawl or energy efficiency: climate policy impacts on natural habitat for the United States of America. PLoS ONE. 4:e6802.

Notaro, M.; Mauss, A.; Williams, J.W. 2012. Projected vegetation changes for the American Southwest: 

combined dynamic modeling and bioclimatic-envelope approach. Ecological Applications. 22:1365-

1388.

Sada, D. 2008. Springs and riparian ecosytems. In: Report from the Clark County MSHCP Ecosystem 

Health Workshop, Las Vegas, NV, January 29-31, 2008. Reno, NV: Desert Research Institute: 5-16.

Smith, M.D.; Knapp, A.K.; Collins, S.L. 2009. A framework for assessing ecosystem dynamics in reponse 

to chronic resource alterations induced by global change. Ecology. 90:3279-3289.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

Williams, J.J.; Jackson, S.T. 2007. Novel climates, no-analog communities, and ecological surprises. 

Frontiers in Ecology and the Environment. 5:475-482.
14 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 15

Chapter 3

Water and Water Use in Southern Nevada

Wayne R. Belcher, Michael J. Moran, and Megan E. Rogers

Executive Summary

Water and water use in southern Nevada is an important issue. The scarcity of 

water resources for both human and biologic communities often leads to intense 

competition for both surface and ground waters. Anthropogenic and climate change 

impacts on scarce water resources need to be understood to assess human and ecosystem health for southern Nevada. Chapter 3 outlines the state of the knowledge 

for hydrology in southern Nevada − ground water, surface water, and water quality − and provides recommendations for filling knowledge gaps. Information is

presented that will help land managers develop strategies to achieve Sub-goal 1.3 

in the SNAP Science Research Strategy, which is to “Restore and sustain proper 

function of southern Nevada’s Watersheds and Landscapes” (see table 1.1).

Groundwater

In southern Nevada, groundwater flow is strongly influenced by the physical framework 

of the system, which is characterized by aquifers, confining units, and flow barriers. 

Groundwater flows through a diverse assemblage of rocks and sediments in the region, 

and geologic structures exert significant control on groundwater movement.

The groundwater hydrology of southern Nevada, as in all flow systems, is influenced 

by geology and climate and varies with time. In general, groundwater moves through 

permeable zones under the influence of hydraulic gradients from areas of recharge to 

areas of discharge in the regional system. The topography produces numerous local 

subsystems within the major flow system. Water that enters the flow system in a recharge 

area may be discharged in the nearest topographic low, or it may be transmitted to a 

regional discharge area.

Three principal aquifer types exist within southern Nevada: (1) volcanic-rock aquifers, which are primarily tuff, rhyolite, or basalt of Tertiary age; (2) carbonate-rock 

aquifers, which are primarily limestones and dolomites of Mesozoic and Paleozoic 

age; and (3) basin-fill aquifers, which are primarily unconsolidated sand and gravel of 

Quaternary and Tertiary age. Any or all three aquifer types may be in, or underlie, a 

particular basin and constitute three separate sources of water; however, the aquifers 

may be hydraulically connected to form a single source. Other rock types within the 

region have low permeability and act as boundaries to the flow of fresh ground water.

In the prevailing conceptual model of interbasin flow, water enters the system as 

interbasin underflow and as recharge from precipitation in upland areas. Because of 

present-day arid conditions, recharge currently is restricted to higher altitudes; virtually 

no recharge occurs and no perennial surface water flows in the lowlands and valley 

floors (except the Colorado River and its tributaries). Ground-water flow paths within 

the system diverge from the highlands and are superimposed on deeper regional flow 

paths that are controlled largely by flow in the regional carbonate-rock aquifer. The 
16 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

SNAP area is contained within two regional groundwater flow systems: the Death Valley flow system and the Colorado flow system. The Death Valley flow system is located 

in the southern part of the Great Basin province and is approximately 100,000 sq. km. 

in area. It consists of recharge areas in the mountains of central and southern Nevada 

and discharge areas of wet playas and springs south and west of the Nevada National 

Security Site and in Death Valley, California. The Colorado flow system is located in 

the Colorado River drainage system just east of the southern part of the Great Basin 

and is approximately 42,000 sq. km. in area. Recharge areas are in some mountainous 

areas within the flow system, but recharge to the system is also from groundwater flow 

from adjacent river systems. The Virgin and Colorado Rivers are the major discharge 

areas of the system.

Current sources of groundwater flow in the region are (1) recharge from precipitation in 

the mountains (usually winter storms) within the model domain; and (2) lateral flow into 

the area, predominantly through the carbonate-rock aquifer. Most groundwater recharge 

results from infiltration of precipitation and runoff on the mountain ranges. Water may infiltrate from melting snowpack in the mountains primarily on volcanic or carbonate rocks 

or adjacent to the mountains from streams flowing over alluvium (fans and channels).

Groundwater discharge in the region is from (1) seeps and spring flow from the regional 

carbonate-rock aquifer and local systems; (2) evapotranspiration (ET); (3) pumpage for 

irrigation, mining, public supply, commercial, and domestic uses; and (4) subsurface 

flow in or out of the area.

Surface Water

In southern Nevada, perennial streamflow is sparse, except in the Colorado River 

drainage. Most surface water in the region is either runoff or spring discharge. Precipitation falling on the slopes of the mountains forms small, intermittent streams that quickly 

disappear and infiltrate as groundwater recharge. In addition, several streams originate 

from snowmelt in the high altitudes of the Spring Mountains. Both of these types of 

streams have highly variable base flows and in dry years have almost imperceptible 

discharges. Springs maintain perennial flow for short distances in some of the drainages.

In most of Nevada, nearly all the streams that originate in the mountains are ephemeral and lose flow to alluvial aquifers as the streams emerge onto the valley floors. In 

southern Nevada, there are three main fluvial systems: the Colorado River (Lake Mead), 

the Virgin and Muddy Rivers, and the Las Vegas Wash. The Colorado River is supplied 

primarily by runoff from the Rocky Mountains. The Virgin and Muddy Rivers and the 

Las Vegas Wash are all tributaries to the Colorado River. The Muddy River begins as 

a series of regional springs in Moapa Valley and drains into the northern arm of Lake 

Mead (Colorado River). The Virgin River originates in Navajo Reservoir in southwestern Utah and enters Lake Mead from the north (forming the northern arm of the lake). 

Prior to the construction of Hoover Dam, the Muddy River joined the Virgin River. The 

Las Vegas Wash, which supports a large wetland, drains Las Vegas Valley and largely 

contains urban runoff, shallow ground water, reclaimed water, and storm water runoff. 

USGS measures discharge on all four of these rivers.

Ground-water discharges at Ash Meadows National Wildlife Refuge, Pahranagat 

National Wildlife Refuge, the Moapa Valley, at numerous springs and seeps in the 

mountainous areas, and along parts of the Amargosa River. Additionally, ground water 

is intersected at Devils Hole, a fissure in the regional carbonate-rock aquifer in the 

Ash Meadows area. Most springs can be classified as local (low discharge and cool 

temperatures) or regional (high discharge and warmer temperatures).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 17

Knowledge Gaps and Management Implications

There are many actual and potential water-quality issues on and within the Federal 

lands of southern Nevada with respect to consumptive use, anthropogenic impacts, and 

preservation of habitat for endangered and threatened species. Desert Research Institute 

(DRI) has conducted extensive work assessing the water quality of local springs in 

southern Nevada as it relates to the viability of biologic communities. USGS, the U.S. 

Environmental Protection Agency, the National Park Service, U.S. Fish and Wildlife 

Service, the Bureau of Land Management, and other Federal, state, and local agencies 

collect water quality information on a somewhat routine basis.

As climate change and increasing population potentially reduce available water 

supplies for both human and biologic communities, the collection and interpretation of 

information to define and assess local and regional hydrologic conditions becomes vital. 

Assessing the information that is regularly collected by Federal agencies in southern 

Nevada has indicated that there are several gaps in data collection. Since there tends 

to be a project-by-project approach to data collection, at times there is no long-term 

program(s) to collect data. Data are collected for the goals of a certain project and once 

the project is completed, data collection ends. There is very little long-term continuity 

or planning on basic data collection that could be used to assess the hydrologic and 

biologic health of southern Nevada. A long-term consistent data collection effort will 

ensure that the right data are collected for evaluation of baseline conditions and assessment of long-term trends.

Recommendations for long-term data collection include: pumping inventories, 

evapotranspiration, recharge, spring discharge, and stream flow.

For a complete discussion of topics in this executive summary, see Chapter 3, Water 

and Water Use in Southern Nevada, in “The Southern Nevada Agency Partnership 

Science and Research Synthesis—Science to Support Land Management in Southern 

Nevada” (RMRS GTR-303).

Key References

Faunt, C.C.; D’Agnese, F.A.; O’Brien, G.M. 2010. Hydrology. In: Belcher, W.R.; Sweetkind, D.S., eds. 

Death Valley regional groundwater flow system, Nevada and California--Hydrogeologic framework 

and transient groundwater flow model. Professional Paper 1711. U.S. Department of the Interior, U.S. 

Geological Survey: 137-159.

Harrill, J.R.; Gates, J.S.; Thomas, J.M. 1988. Major ground-water flow systems in the Great Basin region 

of Nevada, Utah, and adjacent states. U.S. Geological Survey Hydrologic Investigations Atlas HA694-C. 2 sheets. Reston, VA: U.S. Department of the Interior, U.S. Geological Survey. 1:1,000,000; 

[Projection unknown]; colored. 2 sheets. Online: http://pubs.er.usgs.gov/publication/ha694C. [2012, 

Oct 26].

Harrill, J.R.; Prudic, D.E. 1998. Aquifer systems in the Great Basin region of Nevada, Utah, and adjacent 

states. Professional Paper 1409-A. U.S. Department of the Interior, U.S. Geological Survey. 66 p.

Planert, M.; Williams, J.S. 1995. Ground water atlas of the United States, Segment 1, California, Nevada. 

Hydrologic Investigations Atlas 730-B. U.S. Department of the Interior, U.S. Geological Survey. 28 p.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].
18 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 19

Chapter 4

Invasive Species in Southern Nevada

Matthew L. Brooks, Steven M. Ostoja, and Jeanne C. Chambers

Executive Summary

Southern Nevada contains a wide range of topographies, elevations, and climatic 

zones that are emblematic of its position at the ecotone between the Mojave Desert, 

Great Basin, and Colorado Plateau ecoregions. These varied environmental conditions 

support a high degree of biological diversity, but they also provide opportunities for a 

wide range of invasive species. In addition, the population center of Las Vegas valley 

and agricultural areas scattered throughout Clark, Lincoln, and Nye counties, all connected by a network of roads and highways, plus ephemeral and perennial watercourses, 

provide abundant opportunities for new invaders to be transported into and within southern Nevada. Invasive species are a major concern for land managers because of their 

capacity to compete with native species, change habitat conditions, and alter ecosystem 

properties.

Executive Order 13112 issued by President Clinton in 1999 called for the establishment of the inter-departmental National Invasive Species Council (NISC) and creation 

of a national plan to serve as a comprehensive blueprint for Federal actions on invasive 

species. This plan identifies five strategic goals: prevention, early detection and rapid 

response, control and management, restoration, and organizational collaboration. It defines an invasive species as “a species that is 1) non-native (or alien) to the ecosystem 

under consideration and 2) whose introduction causes or is likely to cause economic or 

environmental harm or harm to human health.” Many non-native species do not cause 

harm and are actually beneficial to humans (e.g., crop species). Others are clearly invasive 

and harmful outside of their native range (e.g., European starling). Still other non-native 

species are considered invasive by some, but beneficial or otherwise desirable by others 

(e.g., some ornamental plants, wild horses, and burros). Land managers, policy makers, 

and society in general must determine which non-native species are invasive and pose 

the greatest threats. This chapter provides information that will help land managers develop strategies to achieve Sub-goal 1.2 in the SNAP Science Research 

Strategy, which is to “Protect southern Nevada’s ecosystems from the adverse 

impacts of invasive species” (see table 1.1).

Invasive Plants

Uplands

The majority of invasive plant species that dominate upland areas in southern Nevada 

are annuals. Annuals complete their entire lifecycle in 1 year—germinating, growing, reproducing, and dying—typically from winter to spring. They are ideally suited 

to avoid the most inhospitable arid conditions that characterize most of the year by 

remaining dormant as seeds in the seedbank. Seeds also provide an ideal mechanism 

for dispersal, allowing annual species to spread both within and among areas. Major 
20 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

species of concern include cheatgrass (Bromus tectorum), red brome (Bromus rubens), 

Mediterranean split-grass (Schismus barbatus, Schismus arabicus), red-stemmed filaree 

(Erodium cicutarium), and various mustard species (Brassica tournefortii, Hirshfeldia 

incana, Sisymbrium irio, Sisymbrium altissimum, Malcomia africana).

The greatest threat that invasive plants pose to upland areas of southern Nevada is 

the alteration of fire regimes. Invasive plants also outcompete native plants for limiting 

resources. In addition, the seeds of some invasive plants (e.g., red brome, red-stemmed 

filaree) are eaten and dispersed by native granivores. The desert tortoise will consume 

red brome if there is little else to eat, and this may cause physiological problems associated with potassium levels.

Annual plants are notoriously difficult to manage. Their seeds are easily dispersed 

and often remain viable for many years. Preventing their transport into new areas of 

southern Nevada is the best first line of defense, followed by eradication or containment 

of nascent populations. Washing of equipment and removal of propagules from shoes 

and clothing before leaving infested areas also can help reduce dispersal rates. Repeated 

treatment over a period of years is generally required until the soil seedbank becomes 

exhausted.

Riparian/Aquatic and Springs

Riparian and spring ecosystems are characterized by both annual and perennial 

invasive plant species. Perennial species that have clonal or rhizomatous life forms or 

that are capable of root sprouting are ideally suited to survive the scouring floods and 

sediment deposition that often typify arid riparian ecosystems. These species are also 

often highly competitive with native riparian species. Facultative or obligate riparian 

species include the perennials, giant reed (Arundo donax), Russian olive (Elaeagnus 

angustifolia), camelthorn (Alhagi pseudalhagi), and perennial pepperweed (Lepidium 

latifolium), and the annual rabbitsfoot grass (Polypogon monspeliensis). Upland species 

that utilize seasonal increases in water availability or that occur at the periphery of these 

ecosystems include Russian knapweed (Acroptilon repens), invasive annual grasses such 

as ripgut brome (Bromus diandrus), red brome, and cheatgrass, and invasive mustards.

Perennial species can attain large size, displace native vegetation, and significantly 

affect the physiographic structure of vegetation stands. Tamarisk (Tamarix spp.) is 

perhaps the most infamous of these species in southern Nevada. Conversion of native 

riparian vegetation to tamarisk stands can affect wildlife habitat quality and ecosystem 

properties associated with fire and hydrologic regimes. Even so, this ecosystem continues 

to support a diversity of species including two birds of conservation concern.

Challenges associated with controlling and managing riparian invasive plants differ 

from those of uplands. Many perennial species have persistent below-ground roots and 

rhizomes that make eradicating populations difficult (e.g., giant reed, perennial pepperweed). Also, seeds and other propagules are readily transported in flowing water and by 

the animals that utilize these ecosystems. Mechanical or prescribed fire treatments often 

are used initially to reduce aboveground biomass and stimulate resource re-allocation 

from belowground to aboveground tissue. Then, after regrowth has occurred, chemical 

treatments are used as a follow-up to kill the plants. Treatment of resprouts may be necessary during subsequent years. Long-term of success of these treatments is dependent 

on restoration with native species and continued monitoring to detect reoccurring or 

new invasions.

There are few aquatic plant invaders in southern Nevada, and those that are currently 

present do not pose serious threats. However, there are a few that pose real threats and 

are poised to invade southern Nevada. Eurasian water-milfoil (Myriophyllum spicatum) 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 21

occurs along the Colorado River in the vicinity of Parker Arizona and giant salvinia 

(Salvinia molesta) has been reported farther downstream at the Imperial National Wildlife 

Refuge. Both species have the potential to choke out waterways, increase eutrophication, disrupt food webs, and otherwise significantly alter aquatic habitats of southern 

Nevada. These changes could threaten everything from endemic animals such as pupfish 

and spring snails, to game species such as sunfish, bass, and trout. Options for controlling aquatic plants are limited once the species have established. Educational programs 

promoting watercraft washing and periodic inspections at entry points are potentially 

the most effective way to prevent transport and colonization of new waterways.

Invasive Animals

Terrestrial

While perhaps less conspicuous and less abundant than invasive plants, invasive 

animals can have significant ecological and economic consequences in southern Nevada. Species of concern include Argentine ants (Linepithema humile), imported red 

fire ants (Solenopsis spp.), and feral dogs (Canis familiaris), cats (Felis catus), and 

cattle (Bos primigenius). Wild horses (Equus ferus) and burros (Equus asinus) also 

can impact natural resources and could be considered an invasive species as defined 

by the National Invasive Species Council. However, these species also are viewed by 

many as a national cultural treasure, emblematic of the pioneer spirit of the West, and 

are specifically protected by the 1971 Wild Free-Roaming Horse and Burro Act (Public 

Law 92-195).

Argentine ants are successful and voracious predators in part because they will combine territories and attack other insects including native ant colonies, lizards, snakes 

and small mammals. Red imported fire ants compete with native fire ants, prey on 

invertebrates and vertebrates, and may affect plant assemblages through selective seed 

removal. Wild horse, burros, and cattle can cause damage by trampling vegetation, soil 

compaction, and overgrazing, especially near watering sites. Feral cats and dogs prey 

on birds and other wildlife and are among the main predators of the Federally protected 

desert tortoise.

Control of invasive ants can be difficult. Aside from baiting and chemical control, 

few options exist and even these may have some residual impact on non-target groups. 

Trapping and other removal techniques are effective control strategies for wild horses, 

burros, cattle, and feral cats and dogs. However, these methods are generally not implemented due to animal rights concerns, and comprehensive feral dog and cat programs 

can be very difficult to implement.

Aquatic

Several notable aquatic invasive species exist in southern Nevada including the quagga 

mussel (Dreissena rostriformis), American bullfrogs (Rana catesbeiana), red swamp 

crayfish (Procambarus clarkii), mosquitofish (Gambusia spp.), red shiner (Notropis 

leutrensis), shortfin molly (Poecilia mexicana), cichlids (Oreochromis spp.), and tilapia 

(Tilapia spp.).

Quagga mussels can clog pipes and compromise water intake systems, encrust boats, 

docks and associated facilities, alter the aquatic food web, impact sport fishing and litter 

beaches with their small sharp shells. Bullfrogs are aggressive and voracious predators of native toads and frogs, reptiles, small mammals, and birds, some of which are 

listed under the Endangered Species Act. Mosquitofish, red shiner, and cichlids have 
22 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

adversely affected native invertebrates, amphibians, and fishes. Shortfin mollies prey 

on larval fish including the Federally Endangered Moapa dace (Moapa coriacea) and 

Moapa White River springfish (Crenichthys baileyi moapae).

Prevention is the key to quagga mussel control because even if adults are killed the 

larvae have the ability to evade control measures and later recolonize. Physical methods 

for control of bullfrogs and crayfish include de-watering and temporary habitat removal, 

but this can affect native species. Chemical control methods for fish include picicides 

(e.g., rotenone); however, the effective dosage required will also kill most other cooccurring organisms.

Knowledge Gaps and Management Implications

Prevention is clearly the first line of defense against invasive species. The most 

effectively managed invasive species are those that are kept from being transported to, 

and colonizing within, southern Nevada. Species can be transported accidentally by 

people and equipment, and this mode of transport can be minimized by washing tools 

and vehicles, especially when leaving sites with known local infestations. Other species 

can be transported purposefully into a region, and then spread on their own into wildland 

areas. These purposeful introductions can be discouraged by preventative regulations 

for state and Federal noxious species, and by public education and partnerships with 

the agricultural and ornamental horticultural community for other high priority species 

to help find less invasive alternatives.

Early detection and rapid response requires significant pre-planning to be effective. 

Because there are more species than can be managed, a prioritization process is key to 

refine early detection plans to improve their detectability. Depending on the types of 

existing information and resources available to process the information, a generalized, 

prioritized, or optimized monitoring plan can be developed to improve the efficacy of 

monitoring efforts (fig. 4.1).

Control and management also require prioritization to triage nascent populations 

for rapid response control actions, and the same prioritization concepts can be used as 

those applied to early detection (fig. 4.1). It is also important to continue monitoring and 

retreating these areas for a few years to ensure that there are no surviving individuals. 

Ideally, monitoring should be designed to evaluate the efficacy of control treatments, 

and adjust them accordingly in the future. If the ultimate objectives of control treatments 

are to benefit other species (e.g., natives), biological diversity (e.g., native species diversity), or ecosystem properties (e.g., reduce fire spread potential), then those factors 

should also be targeted for monitoring.

Restoration of robust native ecosystems can improve the resilience of degraded 

areas to subsequent biological invasions. Unfortunately, the specific factors that increase resistance to invasion are poorly understood. As a result, restoration guidelines 

are generally focused on maximizing characteristics like abundance and diversity of 

native species, diversity of functional types, and groups of species important for critical 

aspects of ecosystem function (e.g., nutrient cycling). All restoration projects should 

be carefully monitored to both determine if their restoration targets are achieved and to 

evaluate their effects on invasion resistance.

Organizational collaboration is required to effectively manage invasive species 

because they truly know no political boundaries, and if neighboring land owners are 

not doing their part, then efforts to prevent invasions and the problems that follow will 

often be in vain. Sharing resources and expertise by Federal and local agencies through 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 23

cooperative agreements and through the interagency Southern Nevada Restoration 

Team can assist with the process of collaboration. Cooperative Weed Management 

Areas (CWMA) are formal groups that also can facilitate this process, especially by 

ensuring that species priorities are consistent across land management units and that 

coordinated management plans are maintained over time. For a complete discussion of 

topics in this executive summary, see Chapter 4, Invasive Species in Southern Nevada,

in “The Southern Nevada Agency Partnership Science and Research Synthesis—Science 

to Support Land Management in Southern Nevada” (RMRS-GTR-303).

Figure 4.1–Steps for developing early detection monitoring plans (reprinted with permission 

from Brooks and Klinger 2009)
24 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Key References

Abella, S.R.; Newton, A.C. 2009. A systematic review of species performance and treatment effectiveness 

for revegetation in the Mojave Desert, USA. In: Fernandez-Bernal, A.; De La Rosa, M.A. (eds.). Arid 

environments and wind erosion. Hauppauge, NY: Nova Science Publishers, Inc.: 45-74

Abella, S.R.; Spenser, J.E.; Hoines, J.; Nazarchyk, C. 2009. Assessing and exotic plant surveying program in the Mojave Desert, Clark County, Nevada, USA. Environmental Monitoring and Assessment. 

151:221-230.

Brooks, M.L. 2009. Spatial and temporal distribution of non-native plants in upland areas of the Mojave 

Desert. In: Webb, R.H.; Fenstermaker, L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, E.V.; Miller, D.M. 

(eds.). The Mojave Desert: Ecosystem Processes and Sustainability. Reno, NV: University of Nevada 

Press: 101-124.

Brooks, M.L.; Chambers. J.C. 2011. Resistance to invasion and resilience to fire in desert shrublands of 

North America. Rangeland Ecology and Management. 64:431-429.

Brooks, M.L.; Esque, T.C. 2002. Alien annual plants and wildfire in desert tortoise habitat: status, ecological effects, and management. Chelonian Conservation and Biology. 4:330-340.

Brooks, M.L. and R.C. Klinger. 2009. Practical considerations for detecting and monitoring plant invasions. Pages 168-195 In: Inderjit (ed.). Management of Non-native Invasive Plant Species. Springer, 

Heidelberg, Germany.

Brooks, M.L.; Lusk, M. 2008. Fire management and invasive plants: a handbook. Arlington, VA: U.S. 

Fish and Wildlife Service. 27 pp.

Brooks, M.L.; Pyke, D. 2001. Invasive plants and fire in the deserts of North America. In: Galley, K.; Wilson, T. (eds.). Proceedings of the invasive species workshop: The role of fire inthe control and spread of 

invasive species. Fire Conference 2000: The First National Congress on Fire Ecology, Prevention and 

Management. Miscel. Publ. No. 11. Tallahassee, FL: Tall Timbers Research Station: 1-14.

Courtenay, W.R., Jr.; Deacon, J E. 1983. Fish introductions in the American southwest: a case history of 

Rogers Spring, Nevada. Southwestern Naturalist. 28:221-224.

Hubbs, C.; Deacon, J.E. 1964. Additional introductions of tropical fishes into southern Nevada. Southwestern Naturalist. 9:249-251.

National Invasive Species Council. 2001. Meeting the invasive species challenge: National invasive species management plan. 80 p. Online: http://www.invasivespeciesinfo.gov/docs/council/mp.pdf. [2012, 

Oct 29].

National Invasive Species Council. 2008. 2008-2012 National invasive species management plan. 35 p. 

Online: http://www.invasivespeciesinfo.gov/council/mp2008.pdf. [2012, Oct 29].

Radosevich, S.; Holt, J.; Ghersa, C. 1997. Weed ecology: Implications for management. New York, NY: 

John Wiley and Sons. 589 p.

Richardson, D.M.; Pysek, P.; Rejmanek, M.; Barbour, M.G.; Panetta, F.D.; West, C.J. 2000. Naturalization 

and invasion of alien plants: concepts and definitions. Diversity and Distributions. 6:93-107.

Scoppettonni, G.G. 1993. Interactions between native and nonnative fishes of the upper Muddy River, 

Nevada. Transactions of the American Fisheries Society. 122:599-608.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6]. 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 25

Chapter 5

Fire History, Effects, and Management in 

Southern Nevada

Matthew L. Brooks, Jeanne C. Chambers, and Randy A. McKinley

Executive Summary

Fire can be both an ecosystem stressor and a critical ecosystem process, depending 

on when, where, and under what conditions it occurs on the southern Nevada landscape. 

Fire can also pose hazards to human life and property, particularly in the wildland/

urban interface (WUI). The challenge faced by land managers is to prevent fires from 

occurring where they are likely to threaten ecosystem integrity or human developments, 

while allowing fires to occur where they will provide ecosystem benefits. This chapter 

provides information that will help land managers develop strategies to achieve Subgoal 1.1 in the SNAP Science Research Strategy, which is to “Manage wildland fire to 

sustain southern Nevada’s ecosystems” (see table 1.1).

Fire History and Patterns of Burning

Since the last glacial period at the beginning of the Holocene approximately 10,000 

years ago, the Mojave Desert and southern Great Basin Desert landscapes of southern 

Nevada have experienced continuous arid to semi-arid conditions. A general trend 

towards increased aridity has resulted in an upslope shift in vegetation associations 

and their associated fire regimes during prehistoric times (i.e., pre-settlement). With 

increased aridity and decreased productivity, the spatial extent of fire across southern 

Nevada undoubtedly declined and became increasingly isolated within disjunct mixed 

conifer, piñon and juniper, sagebrush, and riparian ecosystem types.

The first accounting of extensive historic fire in southern Nevada was in the late 

1930s and early 1940s when it was estimated that fires burned 20 percent (approximately 

80,000 acres, 32,375 ha) of the total extent of blackbrush that occurred in the region 

at that time. During the mid-century drought from 1942 to 1975 there were relatively 

few fires, but significant burning occurred after precipitation began to increase in 1976. 

Between 1972 and 2007, approximately one million acres (404,686 ha) burned in 116 

large fires(≥1,000 acres)inLincoln andClark counties, primarily within the blackbrush/

shadscale and Mojave Desert scrub ecosystems (fig. 5.1). Most of that burned acreage 

(90%) occurred in areas that had not previously burned during the 36-year study period, 

8 percent occurred in areas that had burned once before, and 2 percent occurred in areas 

that had burned two or three times before (fig. 5.2). The largest areas burned in the 2005 

and 2006 fire seasons and appear to have been unprecedented during the past century. 

There was a general increase in number of large fires and area burned between 1972 and 

2007, largely due to the 2005 and 2006 fires (fig. 5.3). Trend analyses that only span a 

few decades can be suspect, so the conclusion that fire activity has recently increased 

beyond historical conditions is somewhat tenuous.
26 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Figure 5.1—Large fire chronology 1972 through 2007 inclusive (≥1,000 acres). Shades from cool to warm colors 

represent the chronology of fire occurrence beginning with the oldest fires (blue) and ending with the recent fires 

(red) (reprinted with permission from McKinley and others, in press).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 27

Figure 5.2—Fire frequency of large fires 1972 through 2007 inclusive (≥1,000 acres) (reprinted with permission 

from McKinley and others, in press).
28 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

During the past century, fire activity in southern Nevada has been primarily associated with the warm (positive) phase of the multi-decadal Pacific Decadal Oscillation 

(PDO) cycle during which perennial fuels increase, and secondarily with the El Niño 

phase of the interannual El Niño-Southern Oscillation (ENSO) cycle during which fine 

ephemeral fuels increase due to increased precipitation. The El Niño effect alone may 

not be sufficient to promote large fires, and may only kick in during the latter part of or 

soon after a multi-decadal period of high rainfall associated with the PDO (e.g., after 

1993, and especially during 2005 and 2006). Although intentional burning by humans 

has at times added significantly to acres burned, these fires likely remain small when 

climatic conditions result in sparse fuels.

Plant species in the genus Bromus are directly associated with changes in temporal 

and spatial patterns of burning in upland areas of the Mojave and Great Basin deserts. 

Although these species can undoubtedly alter fire regimes, their influence is ultimately 

tied to the PDO and ENSO cycles. Warm PDO phases are associated with exponential 

population growth of non-native annual grasses, such as that documented for Bromus 

rubens from the late 1970s through 1990. Increasing populations lead to high propagule 

Figure 5.3—Patterns over time (1972-2007) for the number of large fires (≥1,000 acres), total area burned 

(log10 acres), mean fire size (log10 acres), and the proportion of burned area classified as high severity in Clark 

and Lincoln counties, Nevada. The shape of the relationship was derived from generalized additive models. 

Dotted lines are 95% confidence bands (modified with permission from McKinley and others, in press).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 29

production and dispersal into new areas, potentially increasing the regional scope of the 

grass/fire cycle. The El Niño ENSO phase is associated with years of extremely high 

rainfall that lead to episodic spikes in fuel loads created by invasive annual grasses and 

result in heightened fire hazards, especially in lower and middle elevation shrublands. 

The hallmark of the grass/fire cycle is a landscape dominated by invasive annual plants, 

with low abundance of native woody species, and continuous fuelbeds of ephemeral 

fine fuels that promote short fire return intervals (fig. 5.4). These conditions are most 

prevalent in Lincoln County.

Fire Effects and Management Actions

Although land management actions focus on individual fires, the ultimate influence 

of fire across landscapes and over time is attributed to fire regimes. The type (ground, 

surface, or crown fire), frequency (i.e., return interval), intensity (heat released), severity (ecological response), size, spatial complexity, and seasonality of fire define the fire 

regime. When fire regimes are altered (e.g., by plant invasions or land management 

practices) the recovery of the resident species following fire can be compromised and 

landscapes can be converted to new vegetation types.

All fires are not the same, although most published studies on fire effects report the 

effects of “fire” as if it is a univariate factor. The ultimate effects of fire are influenced 

by fire behavior, seasonality, and spatial pattern, in addition to the predominant life 

forms of plants and animals, the time elapsed since the previous fire, and the historical 

and current land uses and weather patterns.

Fire effects and appropriate management actions vary among the various ecosystem types in southern Nevada (table 5.1). Fire management is not a one-size-fits-all 

proposition, and the typical fire management concerns and guidelines for appropriate 

management actions must be examined in the context of each major ecosystem type.

Figure 5.4—A section of the 2005 Southern Nevada Fire Complex in the Tule 

Desert region of Lincoln County, NV. This is an area that had burned within the 

past few decades and was dominated by standing dead Bromus spp. biomass 

at the time of the fire (photo credit, Bureau of Land Management, Ely Field Office files).
30 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 Table 5.1—Typical fire management concerns associated with site and fire characteristics and guidelines for appropriate fuels management, fires suppression, and Emer- gency Stabilization and Rehabilitation (ES&R) actions in the major ecosystem types of southern Nevada. Ecosystem type burned Typical fire management concerns Guidelines for appropriate management actions Alpine and Bristlecone pine Fire – Fires that burn more than a few acres and/or completely consume multiple trees. Site – Tree mortality and increased down woody fuels. Low tree recruitment post-burn and increased dominance of Bromus spp. could alter fire regime. Fuels – Rarely warranted Suppression – Rarely warranted except to protect small and/or isolated stands if excessive fire spread is likely. ES&R – Rarely warranted unless perhaps to control invasive plants or following excessively large and severe fires. Mixed conifer Fire – High severity crown fire. Long fire return interval that allow excessive fuel ac- cumulation. Site – Heavy surface and ladder fuel loads could lead to high severity crown fire. Wild- land/urban interface (WUI) limits fire man- agement options. Fuels – Periodically warranted in the WUI, egress routes, and where surface and ladder fuels have accumulated increasing the risk of large fires. Mechanical treatments may be initially needed, but subsequent treatments should utilize low severity, surface prescribed fire. Follow-up control of invasive plants may be needed during the first few post-treatment years. Suppression – Rarely warranted except in the WUI, egress routes, and where surface and lad- der fuels have accumulated increasing the risk of large fires. Low severity surface fire with mini- mal crowning should be allowed as a natural fire regime component for vegetation management benefits. Follow-up control of invasive plants may be needed during the first few post-fire years. ES&R – May be warranted to stabilize slopes near the WUI or following excessively large and severe fires. Piñon and Juniper Fire – High severity crown fire. Short fire return interval that does not allow re-estab- lishment of shrub understory or trees. Site – Dominant invasive annuals. Short fire return intervals (≤60 years). Fuels – Rarely warranted except in the WUI and egress routes and in shrub-dominated areas exhibiting tree expansion. Prescribed fire may be the more cost-effective over large areas. Fol- low-up control of invasive plants may be needed during the first few post-fire years. Suppression – Warranted in the WUI, and to prevent large, high severity crown fires, but low se- verity surface fire in areas of undesirable tree expansion may be allowed as a natural fire regime component for vegetation management benefits. Follow-up control of invasive plants may be needed during the first few post-fire years. ES&R –Warranted to reestablish native plant community characteristics and to control invasive plants if inadequate perennial herbaceous species and shrubs exist for recovery. Herbicides may allow short-term control, but long-term control requires a wider array of management ac- tions, aerial seedings have low to moderate establishment rates. Sagebrush Fire – Large, homogenous fires Site – Dominant invasive annuals. Short fire return intervals (≤40 years). Fuels – Rarely warranted, except in the WUI and egress routes and perhaps to increase the competitive ability of perennial herbaceous species and prevent invasive annual grass domi- nance. Prescribed fire rarely warranted except perhaps to create a stand-age mosaic in very old late-successional contiguous stands. Follow-up control of invasive plants may be needed during the first few post-treatment years. Suppression – Warranted in the WUI, and in areas with low abundance of perennial herbaceous species and high risk of conversion to annual invasive grasses. ES&R – May be warranted to reestablish the native community and to control invasive plants if inadequate perennial herbaceous species and shrubs exist for recovery. Herbicides may allow short-term control but long-term control requires a wider array of management actions, aerial seedings have low to moderate establishment rates. (continued)
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 31 Blackbrush/shadscale Fire – Large, homogenous fires. Site – Dominant invasive annuals. Short to moderate fire return intervals (≤100 years). Fuels – May be warranted to reduce non-native annual grass fuels, perhaps centered on roads, to facilitate fire suppression. Follow-up treatments may be needed on an annual basis. Suppression – Warranted under most circumstances. Prescribed fire is never warranted except perhaps for experimental purposes. ES&R – May be warranted to reestablish the native community and to control invasive plants if inadequate perennial herbaceous species and shrubs exist for recovery. Herbicides may allow short-term control of non-native annual grasses, but long-term control requires a wider array of management actions including reestablishment of native perennial species. Aerial seedings have low establishment rates. Livestock closures are necessary post-fire to facilitate recovery of na- tive perennial plants. Mojave desert scrub Fire – High severity, large, homogenous fires Site – dominant invasive annuals, short to moderate fire return intervals (≤100 years) Fuels – May be warranted to reduce non-native annual grass fuels, perhaps centered on roads, to facilitate fire suppression. Follow-up treatments may be needed on an annual basis. Suppression – Warranted under most circumstances. Prescribed fire is never warranted except perhaps for experimental purposes. ES&R – May be warranted to reestablish the native community and to control invasive plants if inadequate perennial herbaceous species and shrubs exist for recovery. Herbicides may allow short-term control but long-term control requires a wider array of management actions including reestablishment of native perennial species. Aerial seedings have low establishment rates. Live- stock closures are necessary post-fire to facilitate recovery of native perennial plants. Riparian and Spring Fire – High severity crown, large homoge- neous fire. Site – Dominant invasive perennials. Heavy surface and ladder fuel loads could lead to high severity crown fire. Flood disturbance may have larger effects than fire especially in unregulated riverine systems (e.g. Virgin River) Fuels – May be warranted to reduce non-native tamarisk and Russian olive fuels to reduce high severity fire. Prescribed fire may be the most cost-effective way to reduce invasive plan biomass over large areas, but follow-up control of surviving invasive plants will always be needed during the first few post-fire years, potentially followed by native plant revegetation. Suppression – May be warranted in the WUI or where tamarisk and native vegetation are intermixed, otherwise low to moderate severity fire may be allowed where native fuels pre- dominate as a natural fire regime component for vegetation management benefits, or moderate severity fire may be allowed where tamarisk dominates to remove above-ground biomass as a prelude to other tamarisk control actions such as herbicide treatments followed by native plant revegetation. ES&R – May be warranted to control tamarisk, herbicides may allow short-term control but long- term control requires a wider array of management actions including native plant revegetation which may be accomplished by seedings or outplantings. Table 5.1—(Continued) Ecosystem type burned Typical fire management concerns Guidelines for appropriate management actions
32 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Alpine and bristlecone pine ecosystem fires that burn more than a few acres and/

or completely consume multiple trees are the primary management concern. Due to a 

warming climate, tree mortality and down woody fuels may increase, tree recruitment 

post-burn may decrease, and Bromus spp. may increase to the point that the fire regime 

is altered. Fuels management and fire suppression are currently not warranted, but may 

be in the future. Postfire Emergency Stabilization and Rehabilitation (ES&R) actions 

are rarely warranted, except to reduce the threat of future type conversion mediated by 

invasive plants or excessively large fires.

High severity crown fire is the primary management concern in the mixed conifer 

ecosystem. This type of fire can result from long fire return intervals that allow excessive 

accumulation of surface and ladder fuels. Fuels management in the form of wildland fire 

use in resilient tree communities with low risk of high severity fire may be warranted 

to maintain low levels of ladder fuels. Moderate intensity surface fires at appropriate 

intervals can help maintain managed fuel zones and provide ecosystem benefits in many 

mixed conifer communities. However, in communities with low resilience to fire and 

resistance to invasive species or that are at risk of high severity fires, mechanical thinning 

may be required. Fire suppression is warranted to prevent high severity fires and protect 

the loss of human life and property at the (WUI). Postfire ES&R actions are warranted 

to stabilize slopes in the WUI following large and/or high severity fires, and in areas 

that lack the necessary understory species for ecosystem recovery. Concerns about land 

management activities within the WUI often limit management options, especially the 

use of managed fire. However, these tools are necessary to ultimately reduce threats to 

human life, infrastructure, and ecosystem integrity.

High severity crown fire is also the primary management concern in the piñon-juniper 

ecosystem. Piñon and juniper species are actively expanding into sagebrush and other 

shrub dominated ecosystems in southern Nevada. Progressive increases in fuel loads due 

to tree infilling are increasing the risk of large, high severity fires. In addition, invasion 

of annual grasses (Bromus spp.) at low to mid elevations can shorten fire return intervals 

below levels where either sagebrush species or piñon and juniper trees can reestablish 

(≤60 years). Wildland fire use is warranted in communities that are resilient to fire and

have sufficient understory species (fire-tolerant shrubs and perennial grasses and forbs) 

for natural recovery. Mechanical thinning is the preferred tool in areas that have low 

resilience to fire and/or insufficient understory species for recovery. Fire suppression is 

warranted to prevent high severity fire and protect the loss of human life and property 

at the WUI. Postfire ES&R actions are warranted to reestablish native communities and 

to control invasive plants if inadequate perennial herbaceous species and shrubs exist 

for recovery. Herbicides may allow short-term control but long-term control requires a 

wider array of management actions, and aerial seedings have low to moderate establishment rates.

Large fires that encompass a majority of stands and the initiation of a grass/fire cycle, 

shorter fire return-intervals, and vegetation type-conversion are the primary management 

concerns in the sagebrush ecosystem. Fuels management is rarely warranted, except in 

the WUI and perhaps to increase the competitive ability of perennial herbaceous species and prevent invasive annual grass dominance. Fire suppression is warranted in the 

WUI and in areas with low abundance of perennial herbaceous species and high risk 

of conversion to annual invasive grasses. Postfire ES&R actions may be warranted to 

reestablish the native community and to control invasive plants if inadequate perennial 

herbaceous species and shrubs exist for recovery. Herbicides may allow short-term 

control but long-term control, requires a wider array of management actions, and aerial 

seedings have low to moderate establishment rates.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 33

Blackbrush/shadscale and Mojave Desert scrub fires of most any type, but especially 

large, homogenous fires, are a primary management concern. Increased dominance of 

invasive annual grasses that lead to short to moderate fire return intervals (≤100 years)

is also a management concern. Fuels management may be warranted to reduce invasive 

annual grass fuels, perhaps focused on roadsides, to facilitate fire suppression. Fire 

suppression is warranted under most circumstances. Postfire ES&R may be warranted 

to reestablish the native community and to control invasive plants if inadequate perennial herbaceous species and shrubs exist for recovery. Herbicides may allow short-term 

control, but long-term control requires a wider array of management actions. Aerial 

seedings have very low establishment rates and are not a solution. Postfire closures 

of livestock, wild horses, and burros may be necessary to facilitate recovery of native 

perennial plants.

Riparian and spring ecosystem fires that are large, homogenous, high severity crown 

fire are the primary management concern. Increased dominance of invasive tamarisk 

and accumulation of heavy surface and ladder fuels can lead to high severity crown fire. 

The non-native Russian olive may produce similar results in the future if it becomes 

more dominant. Fuels management may be warranted to reduce invasive tamarisk 

and Russian olive fuel loads. Fire suppression may be warranted in the WUI or where 

invasive and native vegetation are heavily intermixed. Low to moderate severity fire 

similar to the natural fire regime may be warranted where native fuels predominate for 

vegetation management benefits. Moderate severity fire also may be warranted where 

tamarisk dominates to remove above-ground biomass as a prelude to other control and 

restoration actions. Postfire ES&R actions may be warranted to control tamarisk and 

other invasive plants. Herbicides may provide short-term control but long-term control 

requires a wider array of management actions. Native plant revegetation may be accomplished by seedings or outplantings.

Knowledge Gaps and Management Implications

Important take home messages for land managers are that: (1) the effect of an individual fire event should be evaluated within the context of the ecosystem type in which 

it occurs, the characteristics of the fire, and characteristics of the site; (2) fire suppression is the most cost effective way to manage fires across most of southern Nevada, 

except in those ecosystem types where fire is part of the natural disturbance regime and 

wildland fire use can be used to achieve management objectives; and (3) the current 

range of post-fire mitigation tools are either ineffective or their effectiveness is poorly 

documented. Like all aspects of land management, fire management must ultimately be 

placed in the broader context of all the other factors associated with managing landscapes 

in southern Nevada. In some cases, decisions may need to be made regarding where to 

allocate limited resources; in other cases, conflicting objectives may need to be resolved 

between fire management and those focused on other management topics (especially 

natural and cultural resources). For a complete discussion of topics in this executive 

summary, see Chapter 5, Fire History, Effects and Management in Southern Nevada, in 

“The Southern Nevada Agency Partnership Science and Research Synthesis—Science 

to Support Land Management in Southern Nevada” (RMRS-GTR-303).

Key References

Abella, S.R. 2009. Post-fire plant recovery in the Mojave and Sonoran Deserts of North America. Journal 

of Arid Environments. 73:699-707.

Brooks, M.L 1999. Alien annual grasses and fire in the Mojave Desert. Madroño. 46:13-19.
34 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Brooks. M.L. 2011. Effects of high fire frequency in creosotebush scrub vegetation of the Mojave Desert. 

International Journal of Wildland Fire. Online: http://dx.doi.org/10.1071/WF10140.

Brooks, M.L.; D’Antonio, C.M.; Richardson, D.M.; Grace, J.B.; Keeley, J.E.; DiTomaso, J.M.; Hobbs, 

R.J.; Pellant, M.; Pyke, D. 2004. Effects of invasive alien plants on fire regimes. BioScience. 54:677-

688.

Brooks, M.L.; Esque, T.C. 2002. Alien annual plants and wildfire in desert tortoise habitat: status, ecological effects, and management. Chelonian Conservation and Biology. 4:330-340.

Brooks, M.L.; Minnich, R.A. 2006. Southeastern Deserts Bioregion. In: Sugihara, N.G.; van Wagtendonk, 

J.W.; Shaffer, K.E.; Fites-Kaufman, J.; Thode, A.E. (eds.). Fire in California’s ecosystems. Berkeley, 

CA: The University of California Press: 391-414.

Brooks, M.L.; Pyke, D. 2001. Invasive plants and fire in the deserts of North America. In: Galley, K.; Wilson, T. (eds.). Proceedings of the Invasive Species Workshop: The role of fire in the control and spread 

of invasive species. fire conference 2000: The first national congress on fire ecology, prevention and 

management. Miscel. Publ. No. 11. Tallahassee, FL: Tall Timbers Research Station: 1-14.

DeFalco, L.A.; Esque, T.C.; Scoles-Sciulla, S.J.; Rodgers, J. 2010. Desert wildfire and severe drought 

diminish survivorship of the long-lived Joshua tree (Yucca brevifolia: Agavaceae). American Journal of 

Botany. 97(2):243-250.

Dwire, K.A.; Kauffman, J.B. 2003. Fire and riparian ecosystems in landscapes of the western USA. Forest 

Ecology and Management. 178:61-74.

Engel, C.E.; Abella, S.R. 2011. Vegetation recovery in a desert landscape after wildfires: influences of 

community type, time since fire and contingency effects. Journal of Applied Ecology 48: 1401–1410.

Hereford, R.; Webb, R.H.; Longpré, C.I. 2006. Precipitation history and ecosystem response to multidecadal precipitation variability in the Mojave Desert region, 1893-2001. Journal of Arid Environments. 67:13-34.

McKinley, R.A.; Brooks, M.L.; Klinger, R.C. [In press]. Fire history of southern Nevada. Open File Report. Sioux Falls, SD: U.S. Geological Survey, . 62 p.

Petit, N.E.; Naiman, R.J. 2007. Fire in the riparian zone: characteristics and ecological consequences. 

Ecosystems. 10:673-687.

Smith, S.D.; Charlet, T.N.; Fenstermaker, L.F.; Newingham, B.A. 2009. Effects of global change on Mojave Desert ecosystems. In: Webb, R.H.; Fenstermaker, L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, 

E.V; Miller, D.M. (eds.). The Mojave Desert: Ecosystem processes and sustainability. Reno, NV: University of Nevada Press: 31-56.

Spaulding, W.G. 1990. Vegetational and climatic development of the Mojave Desert: The last glacial 

maximum to the present. In: Betancourt, J.L.; van Devender, T.R.; Martin, P.S. (eds.). Packrat middens: 

the last 40,000 years of biotic change. Tucson, AZ: The University of Arizona Press: 166-199.

Tausch, R.J.; Nowak, C.L.; Mensing, S.A. 2004. Climate change and associated vegetation dynamics 

during the Holocene: The paleoecological record. In: Chambers, J.C.; Miller, J.R. (eds.). Great Basin 

riparian ecosystems: Ecology, management, and restoration. Washington DC: Island Press: 24-48.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

Wirth, T.A.; Pyke, D.A. 2009. Final report for emergency stabilization and rehabilitation treatment monitoring of the Keeney Pass, Cow Hollow, Double Mountain, and Farewell Bend fires. Open-File Report 

2009-1152. U.S. Geological Survey. 62 p.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 35

Chapter 6

Species of Conservation Concern and 

Environmental Stressors: Local, Regional and 

Global Effects

Steven M. Ostoja, Matthew L. Brooks, Jeanne C. Chambers, and 

Burton K. Pendleton

Executive Summary

Southern Nevada’s unique landscapes and landforms provide habitat for a diversity of 

plant and wildlife species of conservation concern including many locally and regionally 

endemic species. The high population density and urbanization of the Las Vegas metropolitan area is the source of many local and regional stressors that affect these species 

and their habitats: nitrogen deposition; solar and wind energy and water development; 

recreation, insects and disease; livestock, wild horse, burro, and elk grazing; invasive 

species; and altered fire regimes. Global stressors also affect these species and include 

climate change and CO2 enrichment.

Resource managers must simultaneously consider local, regional, and/or global scale 

stressors for effective management of species of conservation concern. In the sections 

below we provide specific examples of how stressors can affect the range and/or habitat 

of select species of conservation concern within the major ecosystem types of southern 

Nevada. We also provide suggestions for targeted management of southern Nevada’s 

species of conservation concern. This information addresses Sub-goal 1.4 in the SNAP 

Science Research Strategy, which is to “Sustain and enhance southern Nevada’s biotic 

communities to preserve biodiversity and maintain viable populations” (see table 1.1).

Alpine and Bristlecone Pine Ecosystems

Alpine and bristlecone pine ecosystems are susceptible to various stressors and 

disturbances. Global and regional stressors include climate change and atmospheric 

nitrogen deposition. Local stressors include recreation (e.g., snow skiing, rock climbing), 

invasive species (e.g., dandelion), and stochastic disturbance events (e.g., avalanches). 

The limited amount of habitat available in these ecosystems limits the degree to which 

species—especially plants—can respond to stressors. Changes in plant communities 

can affect the habitats of animal species that depend on these ecosystems. Management 

options include monitoring the changes occurring in these ecosystems and developing 

approaches for preventing establishment of invasive species and assisting the migration of plant species like bristlecone pine. Minimizing the effects of recreation can be 

important for species of conservation concern.

Mixed Conifer Ecosystem

The mixed conifer ecosystem is affected by a suite of local and regional stressors 

including invasive species, altered fire regimes, fire and fuels management activities, 
36 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

recreation, and urban and water development. The effect of climate change on episodic and stochastic weather events coupled with long-term effects associated with fire 

suppression, invasive species, and recreation may combine to affect the persistence of 

endemic butterfly species in the Spring Mountains. Four species have been identified 

as conservation priorities including a candidate species for Federal listing including the 

Mt. Charleston blue butterfly (Plebejus shasta charlestonensis). Extreme climate events 

potentially linked to climate change may be adversely affecting butterflies with small 

restricted populations. Ongoing climate change and historical fire suppression have promoted fuel accumulation, which can lead to high intensity fires that burn large areas and 

compromise habitat integrity. Also, various forms of recreational use, including hiking, 

rock climbing, and skiing, may be affecting habitat in this ecosystem. The mixed conifer 

ecosystem is the focus of a diverse and varied set of management programs including 

vegetation and fuels management, rare species conservation, invasive species management, endemic butterfly research, and more. Increased pressure from urbanization and 

recreation will continue to challenge resource managers to find compromises between 

various user groups and species conservation in this ecosystem type.

Piñon-Juniper Ecosystem

The expansion of the piñon and juniper trees into other ecosystem types (e.g., sagebrush)—due to climate change, increased CO2 concentrations, livestock grazing, and fire 

suppression—is occurring in southern Nevada. Progressive infilling of the trees following 

expansion causes reduced dominance or loss of understory plant species, increased fuel 

loads, and a greater risk of larger and higher severity fires. Lower elevation ecosystems 

with depleted understories are highly susceptible to invasion and dominance by annual 

grasses following fire. These changes can significantly affect species of conservation 

concern within these ecosystems, including the desert bighorn sheep and select species 

of birds. Pinyon jay, gray vireo, and gray flycatcher are experiencing significant population reductions due to stand in-filling and piñon die-off in piñon-juniper ecosystems. 

Resource managers should consider using fire, tree-thinning, invasive species management, and restriction of recreational uses when managing this ecosystem. Dynamics 

brought about by a changing climate, including drought and associated interactions with 

insects or other pathogens, will continue to challenge local resource managers.

Sagebrush Ecosystem

The sagebrush ecosystem is subject to a variety of stressors. Sagebrush types at intermediate to high elevations are exhibiting piñon and juniper expansion and progressive 

increases in tree dominance have the potential to compromise the integrity of sagebrush 

ecosystem for specific species or guilds. Sagebrush types at low to intermediate elevations are highly susceptible to invasion by annual grasses, including cheatgrass (Bromus 

tectorum) and red brome (B. madritensis). Conversion to annual grass dominance alters 

soil morphology, soil biota, and native plant diversity, as well as diversity of invertebrates, small mammals, reptiles, and birds. Bird species of conservation concern in 

the sagebrush ecosystem include the sage thrasher, sage sparrow, burrowing owl, and 

others. Each of these species is negatively affected by habitat degradation and loss due 

not only to invasive species and altered fire regimes but also urbanization, energy, and 

other development. Management actions for species of concern should consider climate 

model projections of species range expansion. Also, because so little of this ecosystem 

type naturally occurs in the region, protection of what remains should be a land management priority.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 37

Blackbrush/Shadscale Ecosystem

The blackbrush/shadescale ecosystem is used as winter forage by deer and bighorn 

sheep and is habitat for numerous species of birds and small mammals. Blackbrush is 

one of the most flammable vegetation types in the Mojave Desert, and fires typically 

burn plants to ground level and deplete soil seedbanks. Because natural recruitment is 

low for most plant species in blackbrush vegetation, it may take centuries for natural 

recovery to occur following fire. Disturbances including grazing and recreation facilitate 

establishment of invasive annual grasses (e.g., Bromus spp.), the initiation of a grassfire cycle and, ultimately, type-conversion to invasive annual dominance. Management 

should focus on protecting the remaining remnant patches of the blackbrush/shadscale 

ecosystem by controlling recreation and grazing and preventing fire. Because natural 

regeneration is so limited, especially for blackbrush, it is feared that this ecosystem 

could disappear without both restoration and active management.

Mojave Desert Scrub Ecosystem

The Mojave Desert scrub ecosystem is the most widespread and diverse of all ecosystems in southern Nevada. It is represented by several subtypes, including bajadas, sand 

dunes, and gypsum soils. Increased urbanization promotes human activities that have 

placed this ecosystem type and the habitat it provides for species of concern, like the 

desert tortoise and burrowing owl, at risk. Recreation and associated human activities 

such as target shooting and vehicle impacts are known to directly kill or injure desert 

tortoises. Off-highway vehicles (OHV) use and livestock grazing also have direct effects 

on desert tortoise and also affect tortoise habitat through reductions in native vegetation 

and increases in invasive species. Desert tortoises are subject to diseases including upper 

respiratory tract disease and a shell disease. The Mojave Desert scrub ecosystem will 

be subjected to increased threats from local, regional, and global stressors over time. 

Management efforts should concentrate on large landscape scales to maintain natural 

shrub densities, soil crusts, and healthy native vegetation where disturbance has been 

minimal.

Riparian/Aquatic Ecosystem

The riparian/aquatic ecosystem occurs along the Virgin, Muddy, and Colorado rivers and Las Vegas Wash, and may be the most degraded and manipulated ecosystem in 

southern Nevada. Stressors to this ecosystem include climate change, invasive species, 

altered fire regimes, recreation, and water diversion and extraction. Tamarisk (Tamarix

spp.), an invasive tree, is highly competitive with native species and in many cases is 

the dominant species. Efforts to control tamarisk include the use of chemicals, mechanical methods, and fire and, most recently, the release of a biocontrol agent, the northern 

tamarisk beetle (Diorhabda carinulata), which is native to Eurasia. The riparian/aquatic 

ecosystem is home to numerous species of conservation concern including the Federally 

endangered southwestern willow flycatcher, which was listed due to small population 

sizes, population declines, and habitat threats. Concern exists about the direct and indirect 

effects of the biocontrol beetle on the southwest willow flycatcher. Management should 

consider protecting and potentially enhancing large to medium patches of habitat for 

species of conservation concern with the goal of maintaining a heterogeneous habitat 

complex of open, varied age canopy, shrub thickets dominated by native trees, shrubs, 

and forbs with floodplain and wetland sites intermixed.
38 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Spring Ecosystems

Spring ecosystems are comprised of a range of biophysically diverse sites due to 

differences in water chemistry, slope, substrate type, persistence, morphology, and size. 

These ecosystems are highly sensitive to environmental stressors. Most springs have 

been invaded by invasive aquatic and terrestrial species that can affect ecosystem properties. Springs provide habitat for many spring-obligate species including invertebrates 

and vertebrates. Some of these species have highly limited distributions like the relict 

leopard frog (Rana onca), which is a candidate for Federal listing under the Endangered 

Species Act. The decrease in relict leopard frog populations occurred concurrently with 

the loss or alteration of aquatic habitat due to spring drainage and/or water development 

for agricultural and urban applications. Feral burros also have been implicated in the 

reduction of frog populations due to overgrazing of shoreline vegetation, trampling, 

and urination and defecation into the water. Chytrid fungus is an infectious disease of 

amphibians, and reportssuggest that the fungusis most virulent at temperatures ≤23 °C,

but that its pathogenicity and virulence decline significantly at ≥27 °C. It appears that

thermal springs in the region provide critical habitat where frogs can persist despite 

the presence of chytrid fungus, and that the relict leopard frog occurs naturally only 

in thermal springs that all have source temperatures >30 °C. The habitats that support 

these spring-dependent species are highly imperiled due to direct effects of historical 

and ongoing manipulation of spring sites and the water sources that supply them.

Knowledge Gaps, Research Guidance,

and Management Implications

Actions such as limiting grazing or closing OHV trails have historically been some 

of the primary tools used by land managers in southern Nevada to reduce the effects 

of anthropogenic stressors on species of conservation concern. However, managers are 

increasingly faced with complex and wider spanning issues that are often beyond the 

reach of regionally or locally based management plans. Research that can help disentangle local or regional effects from global effects is needed for conservation planning 

and management of species of conservation concern. This information could help focus 

management toward factors and actions most likely to make a difference.

The overview of species of conservation concern provided here is not a complete 

review of all species and stressor effects, but it is a good representation of the nature 

of single species research in southern Nevada. It is evident from this body of research 

that very little is known about the relative threats posed to, or the mitigation actions 

needed to protect, virtually any species, except perhaps the desert tortoise. Too often 

research jumps immediately to mitigation strategies without first determining what 

specific factors pose the greatest threats and are the most important to mitigate. In 

addition, the evaluation of potential threats typically focuses upon the usual anthropogenic suspects (e.g. OHVs, livestock grazing, invasive species, and climate change) 

without first carefully considering which factors are most likely to pose the greatest 

threats. Finally, fundamental science associated with the life history characteristics and 

habitat requirements of species typically receives the least attention, even though these 

topics are where research programs should actually start. For a complete discussion 

of topics in this executive summary, see Chapter 6, Species of Conservation Concern 

and Environmental Stressors: Local, Regional, and Global Effects, in “The Southern 

Nevada Agency Partnership Science and Research Synthesis—Science to Support Land 

Management in Southern Nevada” (RMRS-GTR-303).
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 39

Key References

Bateman, H.L.; Dudley, T.L.; Bean, D.W.; Ostoja, S.M.; Hultine K.R.; Kuehn M.J. 2010. A river system 

to watch: documenting the effects of saltcedar (Tamarix spp.) biocontrol in the Virgin River Valley. 

Ecological Restoration. 28:405-410.

Bowman, W.D.; Steltzer, H. 1998. Positive feedbacks to anthropogenic nitrogen deposition in Rocky 

Mountain Alpine Tundra. Ambio. 27:514-517.

Brooks, M.L.; D’Antonio, C.M.; Richardson, D.M; Grace, J.B.; Keeley, J.E.; DiTomaso, J.M.; Hobbs, 

R.J.; Pellant, M.; Pyke. D. 2004. Effects of invasive alien plants on fire regimes. BioScience. 54:677-

688.

Bury, R.B.; Esque, T.C.; DeFalco, L.A.; Medica, P.A. 1994 Distribution, habitat use, and protection of 

the desert tortoise in the eastern Mojave Desert. In: Bury, R.B.; Germano, D.J. (eds.). Biology of North 

American tortoises. National Biological Survey, Fish and Wildlife Research 13: 57-72.

D’Antonio, C.M.; Vitousek. P.M. 1992. Biological invasions by exotic grasses, the grass/fire cycle, and 

global change. Annual Review of Ecology and Systematics. 23: 63-87.

Gildart, R.C. 1999. Mountain monarchs: Bighorn sheep. Minnetonka: North World Press.

Jaeger, J.R.; Riddle, B.R.; Jennings, R.D.; Bradford, D.F. 2001. Rediscovering Rana onca: evidence for 

phylogenetically distinct leopard frogs from the border region of Nevada, Utah, and Arizona. Copeia. 

2001: 339-354.

Naiman, R.J.; Decamps, H.; Pollock, M. 1993. The role of riparian corridors in maintaining regional biodiversity. Ecological Applications. 3: 209-212.

Pauli, H; Gottfried, M.; Grabherr, G. 1996. Effects of climate change on mountain ecosystems – upward 

shifting of alpine plants. World Resource Review. 8: 382-390.

Richardson, B.A.; Meyer, S.E. 2012. Paleoclimate effects and geographic barriers shape regional population genetic structure of blackbrush (Coleogyne ramosissima: Rosaceae). Botany. 10: 293-299.

Romin, S. 1997. The relicts that persist in Nevada. Bajada. 5:11.

Romme, W.; Allen, C.D.; Bailey, J.D.; Baker, W.L.; Bestelmeyer, B.T.; Brown, P M.; Eisenhart, K.S.; 

Floyd, L.; Huffmand, D.W.; Jacobs, B.F.;Miller, R.F.; Muldavin, E.H.; Swetnam, T.W.; Tausch, R.J.; 

Weisberg P.J. 2009. Historical and modern disturbance regimes, stand structures, and landscape dynamics in pinon-juniper vegetation of the western United States. Rangeland Ecology and Management. 62: 

203-222.

Sada, D.W.; Nachlinger, J.L. 1998. Spring Mountains ecosystem: Vulnerability of spring-fed aquatic and 

riparian systems to biodiversity loss: Part II, Springs surveyed in 1997. Unpublished report on file at: 

U.S. Department of the Interior, Bureau of Land Management, Las Vegas, NV.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

U.S. Fish and Wildlife Service (USFWS) 2011. Endangered and threatened wildlife and plant; 12-month 

finding on a petition to list the Mt. Charleston blue butterfly as endangered or threatened. FWS-R8-

ES-2010; MO 92210-0-0008.

U.S. Fish and Wildlife Service (USFWS) 2011. Revised recovery plan for the Mojave population of the 

Desert Tortoise (Gopherus agassizii). Sacramento, CA: U.S. Department of the Interior, Fish and Wildlife Service, Region 8, Pacific Southwest Region, 246 p. 
40 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 41

Chapter 7

Maintaining and Restoring Sustainable 

Ecosystems in Southern Nevada

Jeanne C. Chambers, Burton K. Pendleton, Donald W. Sada, 

Steven M. Ostoja, and Matthew L. Brooks

Executive Summary

Resource managers in southern Nevada are faced with the challenge of determining 

appropriate goals and objectives and developing viable approaches for maintaining and 

restoring sustainable ecosystems in the face of rapid socio-ecological and environmental 

change. Many of southern Nevada’s ecosystems are being subjected to anthropogenic 

stressors that span global, regional, and local scales (Chapter 2), and are crossing ecological thresholds to new and often undesirable alternative states (Chapters 4 and 5). 

Protection, prevention, and restoration are integral parts of managing for sustainable 

ecosystems that can supply both ecosystem services and habitat for the diversity of plants 

and animals that occupy the region. This summary addresses the restoration aspects of 

Sub-goal 1.3 in the SNAP Science Research Strategy, which is to “Restore and sustain 

proper function of southern Nevada’s watersheds and landscapes” (see table 1.1).

Managing for Resilience and Resistance

The overarching objective for restoration and management of southern Nevada ecosystems is to maintain and restore sustainable ecosystems that are resilient to disturbance and 

resistant to invasion. Resilience is the capacity of an ecosystem to regain its fundamental 

structure and functioning when subjected to stresses like drought, species invasions, 

or wildfire. It is a function of the underlying ecosystem attributes and processes that 

determine ecosystem recovery. Resistance is the capacity of an ecosystem to retain its 

fundamental structure and functioning (or remain largely unchanged) despite stresses, 

disturbances or invasive species. Resistance to invasion is a function of the biotic and 

abiotic factors and ecological processes in an ecosystem that limit the establishment 

and population growth of an invading species

The abiotic and biotic attributes and ecosystem processes that determine resilience 

to stressors and resistance to invasion can be illustrated with a simple conceptual model 

(fig. 7.1). Environmental characteristics as defined by climate, topography, and soils 

determine the abiotic and biotic attributes and processes of an ecosystem. In turn, the 

abiotic and biotic attributes and processes provide feedbacks to one another and determine 

the inherent potential of an ecosystem to support a given set of ecological conditions and 

plant species. Over time, climate, disturbance, and stressors affect the abiotic and biotic 

attributes and processes and determine the current ecological conditions of the system. 

The current ecological conditions, as influenced by the legacy of past disturbances and 

stressors, determine resilience to disturbance and resistance to invaders at any point in 

time.
42 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Southern Nevada ecosystems differ in ecological resilience and resistance because 

of strong elevation/climate gradients and large differences in their environmental characteristics. The Clark County MSHCP categorizes 11 ecosystems based on elevation 

and soil moisture (fig. 7.2). In general, temperature regimes and effective precipitation 

are the primary drivers of ecological processes because they determine overall resource 

availability and ecosystem productivity. The resilience of southern Nevada ecosystems 

to disturbance and stress typically increases along these environmental/productivity 

gradients. These gradients also determine the likelihood that climate conditions are 

suitable for establishment of invasive annual grasses and other invaders. Ecosystems 

influenced by elevated water tables and high levels of soil moisture are in a separate 

category, as environmental conditions can vary considerably among these ecosystems, 

and factors like soil and water chemistry are important drivers of ecosystem processes.

Restoration Considerations

Restoration and management priorities and activities differ significantly among 

southern Nevada ecosystems because of the large variation in their environmental 

characteristics and, consequently, resilience to disturbance and resistance to invasive 

species. Overarching strategies are protection, prevention and restoration (table 7.1). 

Passive restoration to eliminate or minimize stress is a component of protection and 

prevention; active restoration is a component of prevention and restoration. Guidelines 

for the restoration and management of the diverse ecosystems in southern Nevada can 

be developed based on an understanding of their relative resilience and resistance, the 

dominant stressors affecting them, and the most appropriate actions to maintain and 

restore them (table 7.2).

Figure 7.1–The environmental variables and the ecosystem attributes that influence resilience to disturbance and resistance to invasion. Disturbances can decrease ecological site 

conditions and negatively affect resilience and resistance.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 43

Figure 7.2–A conceptual model that categorizes 11 ecosystems of the Clark County MSHCP 

along two environmental gradients: elevation and soil moisture. This model is based on general knowledge of the environmental gradients that influence southern Nevada ecosystems. 

The shape, size, and relative position of the ellipses and circles are hypothetical (from Desert 

Research Institute 2008). 
44 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Consideration of the predicted effects of climate change on the different ecosystems 

and the implications for management will be needed to maintain and restore southern 

Nevada ecosystems. Climate change models predict high rates of temperature increase 

for desert ecosystems like the Mojave. By 2100, climate change is likely to result in 

the disappearance of some existing climate conditions, the appearance of some novel 

climatic conditions, and the formation of new communities with no past or present analogs. Bioclimatic envelope models predict shifts in the distributions of keystone species 

like creosote bush and Joshua tree, and of invasive species like cheatgrass. Due to the 

rapid rate of change, many species may require assisted migration, and “transformative” 

restoration may be needed in areas that no longer have the climate conditions necessary 

to support the current set of species.

Table 7.1—An approach for categorizing management activities in southern Nevada ecosystems 

based on protection, prevention and restoration (modified from D’Antonio and Chambers 

2006; Brooks and Chambers 2011).

Protection 

Focus Ecosystems with low resilience and/or resistance, ecosystems of high conservation concern, and ecosystems at risk of crossing ecological thresholds to new 

alternative states. 

Objectives Eliminate or minimize current and future stressors. 

Activities Closure or active control of recreational use and burro and cattle grazing to allow natural regeneration; fire suppression in Mojave Desert scrub, blackbrush 

and lower elevation sagebrush and piñon and juniper ecosystems to prevent an 

invasive annual grass-fire cycle; control of placement and development of road 

and utility corridors, urban expansion, and solar energy projects to minimize 

fragmentation and surface disturbance.

Prevention

Focus Ecosystems with inherently higher resilience and/or resistance and ecosystems 

in moderate to high ecological condition. 

Objectives Maintain or increase resilience and resistance of areas with declining ecological 

conditions. 

Activities Vegetation management to decrease risk of high severity fires, maintain understory composition, and prevent invasion; mechanical vegetation management 

treatments to decrease decadent or over-dense shrubs and increase perennial 

herbaceous vegetation.

Restoration

Focus Ecosystems known to respond favorably to restoration treatments and ecosystems of conservation concern. 

Objectives Increase resilience and resistance of ecosystems by revegetating or rehabilitating areas disturbed by fire, recreational activities, road and utility corridors, 

urban expansion, solar energy projects, and other surface disturbances. Provide 

assisted migration for species being displaced by climate change.

Activities Soil surface stabilization to curtail dust; seedbed preparation to mitigate soil 

physical and chemical disturbance and provide favorable conditions for plant 

establishment; transplanting or seeding native species adapted to the local environment and climate warming. 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 45

Table 7.2—Resilience and resistance characteristics of the major ecosystem types in southern Nevada and guidelines for 

appropriate management actions. 

Ecosystem Resilience and resistance Guidelines for appropriate management actions

Alpine and 

Bristlecone 

pine

Resilience – Very low to low. Extreme temperatures, short growing 

seasons, slow growth, and low 

establishment rates. Low capacity to adapt/migrate with climate 

warming.

Resistance – Moderate to high. 

Few annual species are adapted to 

the extreme environment; resistance 

may decrease as climate warms. 

Protection – Primary emphasis. Minimize stress from recreational 

activities, including firewood gathering. Monitor changes in temperature and precipitation and in species distributions and community 

composition. 

Prevention – Rarely warranted except to suppress fires with potential to spread. 

Restoration – Rarely warranted except for assisted migration of 

trees or revegetation of areas with die-off. Information on species 

environmental and establishment requirements is required.

Mixed conifer Resilience – Moderate to high. 

Relatively high precipitation, long 

growing seasons, and moderate 

growth and establishment rates. 

Potential to migrate upslope with 

climate warming.

Resistance – Moderate to low. Multiple non-native invaders adapted to 

environmental conditions; competition with invaders from established 

native plants can be high.

Protection – Control inappropriate recreational activities and overgrazing; detect and eradicate invasive species.

Prevention – Warranted to decrease fuel loads, restore understory 

composition, and decrease invasion. Potential for Wildland Fire 

Use and prescribed fire where risk of large or high severity fire 

is low and fire spread can be controlled, and for tree thinning followed by surface fire or pile burning in WUI and areas with higher 

fuel loads. However, more information is needed on the responses 

of southern Nevada ecosystems.

Restoration – Warranted following surface disturbance or in areas 

with insufficient fire tolerant understory species for site recovery 

after fire. Seed burial (drilling) or transplanting natives adapted to 

local site conditions and climate warming preferred.

Piñon and 

Juniper

Resilience – Moderate. Moderate 

precipitation, long growing seasons, moderate to slow growth and 

establishment. Potential for die-off 

at lower elevations with climate 

warming.

Resistance – Low. Many non-native 

invaders adapted to environmental 

conditions; competition from established shrubs and herbaceous species dependent on site productivity 

and ecological condition.

Protection- Control inappropriate recreational activities and overgrazing; detect and eradicate invasive species; suppress fires at 

lower elevations and that threaten ecosystem integrity.

Prevention-Warranted to decrease fuel loads, restore understory 

composition, and decrease invasion. Focus is on mesic sites in 

early to intermediate stages of tree expansion, and in moderate to 

high ecological condition. Potential for Wildland Fire Use and prescribed fire on productive sites at high elevation; mechanical treatments more appropriate on sites with low productivity. 

Restoration – Warranted following surface disturbance and in areas with insufficient fire tolerant understory species for site recovery after fire. Seed burial (drilling) or transplanting natives adapted 

to local site conditions and climate warming preferred.

Sagebrush Resilience – Moderate to low. 

Types at higher elevations and 

with deeper soils have moderate 

resilience; types at lower elevations and on shallow soils have low 

resilience.

Resistance – Moderate to low. 

Types at higher elevations are more 

resistant to annuals invaders than 

those at lower elevations. Resistance generally decreases as site 

productivity or herbaceous perennial species and ecological condition decreases. 

Protection- Control inappropriate recreational activities and overgrazing, detect and eradicate invasive species, suppress fires at 

lower elevations and that threaten ecosystem integrity.

Prevention– Warranted to restore or maintain sagebrush types, 

and increase understory species and resistance to invaders. 

Focus is on resilient and resistant sites. Potential for Wildland Fire 

Use and prescribed fire to control tree expansion, and shrub mowing and selective herbicides to decrease competition from overstory sagebrush. Information on ecosystem response is needed.

Restoration – Warranted following surface disturbance and 

in areas with insufficient fire tolerant understory species for site 

recovery after fire. Seed burial (drilling) or transplanting natives 

adapted to local site conditions and climate warming preferred. 

Livestock closures required post-restoration to facilitate recovery.

(continued)
46 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Blackbrush Resilience – Low to very low. Low 

precipitation, moderately high temperatures, episodic recruitment. 

Potential to migrate upslope with 

climate warming.

Resistance – Low to very low. Environmental conditions conducive 

to establishment of invasive annual 

bromes. Low competition from native species due to low productivity. 

Protection – Primary emphasis. Suppress fires, actively control 

cattle and burro grazing and inappropriate recreational activities, 

detect and eradicate new invaders.

Prevention – Not warranted under most circumstances.

Restoration – Warranted following surface disturbance and 

in areas with insufficient fire tolerant understory species for site 

recovery after fire. Seed burial (drilling) or transplanting natives 

adapted to local site conditions and climate warming preferred. 

Livestock closures required after fire and restoration activities to 

facilitate recovery of native perennial plants.

Mojave Desert 

scrub

Resilience – Very low. Extreme 

environmental conditions, episodic recruitment, slow ecosystem 

recovery.

Resistance– Low. Environmental 

conditions of more mesic systems 

conducive to establishment of annual grasses; few species adapted 

to most extreme conditions. Low 

competition from natives due to low 

productivity. 

Protection – Primary emphasis. Suppress fires, actively control 

inappropriate recreational activities and overgrazing by cattle, 

horses and burros, detect and eradicate new invaders.

Prevention – Not warranted under most circumstances.

Restoration – Warranted following surface disturbance and 

in areas with insufficient fire tolerant understory species for site 

recovery after fire. Seed burial (drilling) or transplanting natives 

adapted to local site conditions and climate warming preferred. 

Livestock closures required after fire and restoration to facilitate 

recovery of native perennial plants.

Riparian and 

Spring

Resilience –Low to moderately 

high. High water availability but 

high water temperatures, harsh 

water chemistry, and scouring 

floods. Water availability likely to 

decrease with climate warming.

Resistance – Low. Many invasive 

species in a variety of taxa adapted 

to high availability of water. 

Protection– Maintain or increase current water allocations and in 

stream flows, actively control inappropriate land uses, recreational 

activities and overgrazing, detect and eradicate new invaders.

Prevention- Warranted to reduce non-native tamarisk and Russian 

olive and to manage fuels. Biocontrol, prescribed fire, mechanical 

treatments, or herbicides can be used, but restoration of native 

species must follow. 

Restoration– Warranted to maintain river and stream channels 

by manipulating flow regimes, and to restore or create habitat for 

native species of concern. Methods include manipulating water 

depths, velocities and temperatures to meet requirements for species establishment and persistence, and revegetating with native 

species adapted to the site conditions.

Table 7.2—(Continued)

Ecosystem Resilience and resistance Guidelines for appropriate management actions

Knowledge Gaps

Cross-cutting information needs for restoration and management of southern Nevada’s 

diverse ecosystems include a better understanding of the factors that determine resilience 

and resistance and of the interacting effects of the region’s stressors. Knowledge of the 

environmental conditions required for establishment and persistence of native plant 

species and methods for their restoration also is needed. Information needs relative to 

the region's major stressors follow:

Climate Change. More accurate predictions of changes in both temperature and precipitation; ecosystem specific information on the effects of climate change on species 

distributions, disturbance regimes and recovery processes.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 47

Land Use. Knowledge of the distribution and extent of current and future land uses 

and their effects on current and future ecosystem resilience; information on the minimum patch sizes and degree of fragmentation that ecosystems can tolerate and still 

persist; land use planning tools to ensure land use is consistent with maintaining and 

restoring ecosystems.

Invasive Species. Increased knowledge of feedbacks to invasion from regional 

stressors like increased CO2, altered fire regimes, and overgrazing; knowledge of the 

environmental conditions required for establishment and persistence of invasive plants 

and of their capacities to adapt and migrate in a warming environment; methods for 

controlling invaders and restoring natives that are consistent with ecosystem restoration and maintenance.

Fire. Increased knowledge of fire effectson annual species invasion and ecosystem recovery for the different ecological sites that characterize Mojave Desert 

scrub and blackbrush ecosystems; increased knowledge of the interacting effects 

of precipitation, ecosystem productivity, and understory species composition on 

fire return intervals for southern Nevada mixed conifer and piñon and juniper ecosystems; fire and fire surrogate tools for mixed conifer, piñon and juniper, and 

sagebrush ecosystems.

Management Implications

Protection is a critical component of restoring and maintaining southern Nevada 

ecosystems due to the arid environment and numerous stressors. Preventative management is a viable option only in more mesic or higher elevations ecosystems that do 

not comprise much of the total land area. Restoration is challenging in all ecosystems. 

Maintaining sustainable ecosystems will require a greater focus on assessing ecological 

condition, prioritizing restoration and management activities, and selecting the most 

appropriate treatments. Monitoring and adaptive management will be essential.

Assessment and Prioritization

An integrated and consistent assessment of southern Nevada ecosystems and their 

relative resilience and resistance is necessary to categorize and prioritize management 

and restoration activities. Addressing the widespread stressors affecting these ecosystems 

and providing habitat for species of concern requires a broad scale approach that crosses 

administrative boundaries. Most management plans now encompass landscapes with 

multiple project areas and are developed in consultation with partner agencies. Several 

tools already exist for developing landscape-scale and cross-boundary assessments. Soil 

surveys exist for most of southern Nevada including spring systems and lands managed by the BLM, most of the Desert National Wildlife Refuge, and Lake Mead and 

are available from the USDA Natural Resources Conservation Service (NRCS). Soil 

characteristics, along with climate and topography, determine the potential to support 

a given ecological site type (fig. 7.1). Draft ecological site descriptions (ESDs) exist 

for most of the region that has soil surveys and are available from the Nevada State 

Office, NRCS. Soil types and ESDs can be used in a GIS environment as the basis for 

evaluating the relative resilience and resistance of the ecosystems in the region, and the 

degree to which current ecological conditions deviate from potential conditions. Recent 

research has developed geospatial tools for identifying critical habitat for species of 

concern in the Great Basin that could be used in southern Nevada. Methods also have 

been developed to examine linkages among adjacent ESDs and the interacting effects 

of landforms and disturbances.
48 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Restoration and Management Approaches

Once an area has been prioritized for active restoration and/or management, a series of 

logical steps can be used to develop the restoration plan: identifying landscape priorities 

and ecological sites, determining the current state of the site, selecting the appropriate 

action(s), and determining post-treatment management. A useful approach that asks 

questions to identify the information required in each step is provided in table 7.3. These 

questions can be modified to include the specific information needed for restoration of 

different ecosystem types.

Table 7.3—General guidelines for conducting a restoration project in southern Nevada (modified from Miller and others 2007; 

Pyke 2011; Tausch and others 2009).

Steps in the process Questions to be addressed

I. Identify landscape priorities 

 and ecological sites 1. Where are priority sites for protection, prevention and restoration? Consider the 

 landscape context.

 2. What are the topographic characteristics and soils of the site? Verify soils mapped 

 to the location and collect information on soil texture, depth and basic chemistry 

 (pH, calcium carbonate, etc.)

 3. How will topographic characteristics and soils affect vegetation establishment and 

 erosion? Evaluate erosion risk based on topography and soil characteristics. 

 4. What is the potential native plant community for the site? Match soil components 

 to their correlated ESD. This provides a list of potential species for the site.

II. Determine current state 

 of the site 5. Is the site still within the reference state of the state and transition model for this 

 ecological site?

III. Select appropriate action 6. How far does the site deviate from the reference state? 

 7. Do sufficient perennial shrubs and herbaceous species exist to facilitate recovery? 

 No action is needed.

 8. Are invasive species a minor component? Protection or preventative management 

 may prevent conversion. 

 9. Do invasive species dominate the site while native life forms are missing or

 severely under represented? Active restoration is required to restore habitat.

 10. Are species from drier or warmer ecological sites present? Restoration with

 species from the drier or warmer site should be considered. 

 11. Have soils or other aspects of the physical environment been altered? The site may 

 have crossed a threshold and represent a new ecological site type requiring new 

 site-specific restoration approaches.

IV. Determine post-treatment 12. How long should the site be protected before land uses begin? In general, sites with

 management lower resilience and resistance should be protected for longer periods. 

 13. How will monitoring be performed? Restoration effectiveness monitoring includes a 

 complete set of measurements, analyses, and a report.

 14. Are adjustments to the restoration approach needed? Adaptive management is 

 applied to future projects by compiling information based on consistent findings from 

 multiple locations.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 49

Monitoring Activities

Monitoring programs designed to track ecosystem changes in response to both 

stressors and management actions can be used to increase understanding of ecosystem 

resilience and resistance, realign restoration and management approaches, and implement adaptive management. Information is increasing on likely changes in southern 

Nevada ecosystems with additional stress and climate warming, but a large degree of 

uncertainty still exits. Strategic placement of monitoring sites and repeated measurements of key abiotic (precipitation, temperature, evaporation) and biotic (dominant 

native and exotic species) variables and ecological conditions can be used to decrease 

uncertainty and increase the effectiveness of management decisions. Monitoring sites 

should span the environmental/ productivity gradients and ecosystem types that occur 

in southern Nevada. In addition, areas of high priority should be monitored including 

(1) ecosystem types of small extent under development pressure like mesquite/catclaw 

and salt desert shrub; (2) ecosystems that support numerous species of conservation 

concern like springs and riparian areas; (3) ecotones between ecosystem types where 

changes in response to climate are expected to be largest; (4) ecological sites with different climatic conditions and soils that are exhibiting invasion and repeated fires; and 

(5) ecological sites with different climatic conditions and soils that are exhibiting tree 

expansion and increased fire risk. Monitoring the response of ecosystems to management actions and active restoration also is of high priority as it provides information on 

treatment effectiveness that can be used to adjust methodologies.

Monitoring activities are most beneficial when consistent approaches are used among 

and within agencies to collect, analyze, and report monitoring data. Common databases 

can be used by agency partners to record and share monitoring data, like the USGS Land 

Treatment Digital Library, to facilitate this process.

For a complete discussion of topics in this executive summary, see Chapter 7, Maintaining and Restoring, Sustainable Ecosystems in Southern Nevada, in “The Southern 

Nevada Agency Partnership Science and Research Synthesis—Science to Support Land 

Management in Southern Nevada” (RMRS-GTR-303).

Key References

Abella, S.R; Newton, A.C. 2009. A systematic review of species performance and treatment effectiveness 

for revegetation in the Mojave Desert, USA. In: Fernandez-Bernal, A.; De La Rosa, M. A. (eds.). Arid 

environments and wind erosion. Hauppauge, NY: Nova Science Publishers, Inc: 45-74.

Allen, C.D.; Savage, M.; Falk, D.A.; Suckling, K.F.; Swetnam, T.W.; Shulke, T.; Stacey, P.B.; Morgan, P.; 

Hoffman, M.; Klinger, J.T. 2002. Ecological restoration of southwestern ponderosa pine ecosystems: a 

broad perspective. Ecological Applications. 12:1418-1433.

Anderson, B.W.; Russell, P.E.; Ohmart, R.D. 2004. Riparian revegetation: an account of two decades of 

experience in the arid southwest. Blythe, CA: Avvar Books. 268 p.

Bainbridge, D. A. 2007. A guide for desert and dryland restoration. Washington, DC: Island Press. 391 p.

Bestelmeyer, B.T; Tugel, A.J.; Peacock, G.L. Jr., Robinett, D.G., Shaver, P.L., Brown, J.L., Herrick, J.E., 

Sanchez, H., Havstad, K.M. 2009. State-and-transition models for heterogeneous landscapes: a strategy 

for development and application. Range Ecology and Management 62:1-15.

Bradley, B.A.; Oppenheimer, M.; Wilcove, D.S. 2009. Climate change and plant invasions: restoration 

opportunities ahead? Global Change Biology. 15:1511-1521.

Briggs, M. K. 1996. Riparian ecosystem restoration in arid lands: strategies and references. Tucson, AZ: 

The University of Arizona Press. 159 p.

Brooks, M.L.; Chambers, J.C. 2011. Resistance to invasion and resilience to fire in desert shrublands of 

North America. Rangeland Ecology and Management. 64:431-438.

Brooks, M.L.; Minnich, R.A. 2006. Fire in the Southeastern Desert Bioregion. In: Sugihara, M.G.; van 

Wagendonk, J.W.; Fites-Kaufman, J.; Shaffer, K.E.; Thode, A.E. (eds.). Fire in California ecosystems. 

Berkeley, CA: University of California Press: 391-414.

Harris, J.A.; Hobbs, R.J.; Higgs, R.; Aronson, J. 2006. Ecological restoration and global climate change. 

Restoration Ecology. 14:170-176.
50 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Lovich, J.E.; Bainbridge, D. 1999. Anthropogenic degradation of the southern California desert ecosystem 

and prospects for natural recovery and restoration. Environmental Management. 24:309-326.

Pyke, D.A. 2011. Restoring and rehabilitating sagebrush habitats. In: Knick, S.T.; Connelly, J.W. (eds.). 

Greater sage-grouse: ecology and conservation of a landscape species and its habitats. Studies in Avian 

Biology. Berkeley, CA: University of California Press: 531-548.

Sada, D.W.; Williams, J.E.; Silvey, J.C.; Halford, A.; Ramakka, J.; Summers, P.; Lewis, L. 2001. Riparian 

area management: a guide to managing, restoring, and conserving springs in the western United States. 

Technical Reference 1737-17. Denver, CO: Department of the Interior, Bureau of Land Management. 

BLM/ST/ST-01/001+1737.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

Webb, R.H.; Defalco, L.A.; Esque, T.C.; Medica, P.A. 2009. A review of selected long-term ecological 

studies of the Mojave Desert ecosystem. In: Webb, R.H.; Fenstermaker, L.F.; Heaton, J.S.; Hughson, 

D.L.; McDonald, E.V.; Miller, D.M. (eds.). The Mojave Desert. Las Vegas, NV: University of Nevada 

Press: 429-456.

Weigand, J.; Rodgers, J. 2009. Active restoration for the Mojave Desert. In: Webb, R.H.; Fenstermaker, 

L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, E.V.; Miller, D.M. (eds.). The Mojave Desert. Las Vegas, 

NV: University of Nevada Press: 378-409. 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 51

Chapter 8

Human Interactions With the Environment 

Through Time in Southern Nevada

Carol B. Raish

Executive Summary

Southern Nevada is rich in irreplaceable cultural resources that include archeological remains, historic sites, cultural landscapes, and other areas of significance to Native Americans and other cultural groups. This chapter provides information related to 

Goal 2 in the SNAP Science Research Strategy, which is to “Provide for responsible 

use of Southern Nevada’s lands in a manner that preserves heritage resources and 

promotes an understanding of human interaction with the landscape.” Specifically, it 

addresses Sub-goal 2.1, which is to “Develop an understanding of human interactions 

with the environment through time” (see table 1.1). The summary presents a review of 

human occupation in the region as derived from studies of southern Nevada’s cultural 

resources. The depth with which these questions can be discussed is dependent upon 

the nature and extent of archeological survey coverage of the region and the nature of 

the resources themselves (fig. 8.1). The area shows wide ranging use of resources and 

environmental zones over time. The focus of this overview is on the time periods primarily informed by archeological sources, which is roughly from 11,950 BP (10,000 BC) 

to 100 BP (AD 1850). This period encompasses the end of the Pleistocene/beginning 

of the Holocene until occupation by Euro-Americans.

Focal Area

The focal area is mainly southern Nevada’s Clark County but lands in Lincoln and Nye 

Counties are also included, as well as a small portion of Mohave County, Arizona. The 

geographic focus includes areas surrounding Lake Mead, the Muddy and Virgin Rivers, 

and the Las Vegas Valley. It extends west to Sloan Canyon National Conservation Area, 

the Spring Mountains National Recreation Area, and Ash Meadows National Wildlife 

Refuge. Physiographic features important for human occupation in and surrounding the 

location include the Muddy and Virgin Mountains, Moapa and Virgin Valleys, the Valley of Fire, the Muddy and Virgin Rivers, Las Vegas Valley, and the Spring Mountains 

(figs. 8.2 and 8.3).

Culture History

Tables 8.1 and 8.2 outline the chronology of the region. The earliest period of human 

occupation in the area is the Paleo-Archaic, known primarily from diagnostic projectile 

points. Paleoenvironmental research in southern Nevada and the Great Basin indicates 

that climatic changes from a moister, temperate regime to current climatic conditions began 

around 13,950 BP (roughly 12,000 BC) with deglaciation of the mountains within the area. 
52 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Figure 8.1—Map of southern Nevada archeological survey coverage.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 53

Figure 8.2—Map of the Moapa and Virgin Valleys.
54 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Figure 8.3—Map of the Las Vegas Valley.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 55

Table 8.1—Chronological sequence for the Moapa and Virgin River Valleys (adapted from Ahlstrom 

and Roberts 20121; Ezzo 19952; Harper and others 20063; Lyneis 20124). Question marks 

indicate uncertain date range.

Period Subperiod Date range Source

Paleo-Archaic 11,950-7450 BP (10,000-5500 BC) 3

Paleo-Indian 11,450-10,950 BP (9500-9000 BC) 2, 3

Early Archaic 11,150-7450 BP (9200-5500 BC 3

Archaic Middle Archaic 7450-4950 BP (5500-3000 BC) 3

Late Archaic 4950-2350 (?) BP (3000-400 (?) BC) 3

Late Archaic/Early

Agricultural 2350 (?)-1450 BP (400 (?) BC-AD 500) 3

Virgin Branch 1600-750/650 BP (AD 350-1200/1300) 1, 3, 4

Moapa phase 1600-1400 BP (AD 350-550) 3

Muddy River phase 1400-1200 BP (AD 550-750) 3

Lost City phase 1200-800 BP (AD 750-1150) 3

Mesa House phase 800-750/650 BP (AD 1150-1200/1300) 1, 3, 4

Late Prehistoric and 

Protohistoric 750/650-150 BP (AD 1200/1300-1800) 3, 4

Historical 150-0 BP (AD 1800-1950) 3

Table 8.2—Chronological sequence for the Las Vegas Valley (adapted from 

Roberts and Ahlstrom 2007).

Period Subperiod Date range

Paleo-Archaic 11,450-7450 BP (9500-5500 BC)

Paleo-Indian 11,450-10,950 BP (9500-9000 BC)

Early Archaic 11,150-7450 BP (9200-5500 BC) 

Archaic Middle 7,450-4950 BP (5500-3000 BC)

Late 4950-1450 BP (3000 BC-AD 500)

Terminal Late 1949-1450 BP (AD 1-500)

Ceramic Early 1450-950 BP (AD 500-1000)

Middle 950-450 BP (AD 1000-1500)

Late 450-100 BP (AD 1500-1850)

Historical Early 450-100 BP (AD 1500-1850)

Late 100-50 BP (AD 1850-1900)

A continuing trend toward aridity and drying of pluvial lakes is indicative of southern Nevada’s 

climate in the Holocene, with an increase in succulent plants in lower environments and a movement of woodlands to higher elevations. Clovis points attached to the thrusting spear or atlatl 

(spear-thrower) are representative of the Paleo-Indian occupation found across the Americas and 

are generally considered to represent the activities of nomadic groups hunting and scavenging 

Pleistocene megafauna, represented by mammoth, camel, horse, and bison. Paleo-Indian sites 

include camps, kill and butchering locations, and isolated projectile points. 
56 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

The Archaic periods represent adaptation to Holocene animal and plant resources 

similar to those of the present. Site locations indicate that groups continued a mobile 

strategy seasonally exploiting ecological zones from a wide range of elevations and 

landforms. During these times, plant procurement and processing tools, storage cists, 

and snares and traps for small game came into use. In earlier portions of the period, 

sites seem to be located near water sources such as drainages and remnant pluvial lakes. 

Unusually arid conditions are thought to drive the settlement pattern. Later portions of 

the period are described as having a climatic shift toward greater precipitation and an 

increasing diversity of plant resources available to southern Nevada groups, with sites 

occurring in riverine areas, lowland zones, and mountains. Upland sites were also more 

frequently used in later portions of the period. Both of these trends suggest the growing 

importance of plant foods. Sites include caves, rockshelters, campsites, roasting pits, 

hearths, and scatters of flaked and ground stone.

The following periods represent the beginnings of agriculture in the region and its 

growing importance as a subsistence strategy, although exploitation of wild resources 

coupled with seasonal movement continued to play an important role in food procurement. 

These time periods represent the beginning of the Virgin Branch Ancestral Puebloan 

occupation of the area. The Virgin Branch is most strongly represented in the Moapa and 

Virgin River Valleys, expanding its occupational range into the Las Vegas Valley during 

the later portions of the period when population peaked in the area. Key features include 

the appearance of the bow and arrow, ceramics, two-handed manos, and various types 

of metates (grinding implements). Habitations consisted of pit structures with aboveground, surface structures appearing in the later portions of the period. Site location in 

relation to the best agricultural land in the valley indicates the growing importance of 

agriculture during these times. 

By approximately 750/650 BP (AD 1200/1300), the Virgin Branch cultural tradition 

was no longer present in southern Nevada. With the decline of agriculture as a major 

subsistence practice in the area, archeological remains reflect a return to a more nomadic 

foraging way of life that was supplemented by smaller-scale agriculture. This adaptation 

is associated with the Southern Paiute, who were residents of the region at European 

contact and who occupy southern Nevada today.

European Contact

The first reported direct European contacts were with the Spanish in the late 1700s 

with the expeditions of Garcés and of Domínguez and Escalante. After the explorers, 

trappers, and traders extended their operations into the area, an active slave trade began 

that lasted from the late 1700s to the mid-1850s. Captives, often Southern Paiute, were 

transported along the Old Spanish Trail between California and New Mexico. This slave 

trade seriously impacted the people of the Moapa and Las Vegas Valleys forcing them 

away from favorable agricultural lands, depopulating some Southern Paiute bands, and 

increasing their hostility and fear of travelers and other outsiders. Slave raiding continued 

in the region until the mid-1850s when steps taken by the Mormons and the territorial 

legislature ended the trade.

During the 1850s, the Old Spanish Trail became the Mormon Road, which brought 

settlers and other travelers to the area. Increased Euro-American settlement displaced 

the Southern Paiute from long-used agricultural, foraging, and hunting lands, which 

became depleted by livestock grazing and larger farming operations. Interactions with 

Mormon settlers increased so that by the 1870s the majority of Southern Paiute had 

direct contact with Euro-Americans, with some settling near Mormon communities.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 57

Expansion of Euro-American settlement led to increasing hostilities. In 1873, an executive order was issued setting aside 3,900 square miles (10,101 square kilometers) to 

form the Moapa River Reservation. The reservation was expanded in 1874 then sharply 

reduced to 1.5 square miles (2.4 square kilometers) in 1875 to accommodate complaints 

from white settlers within the reservation lands. In 1982, the reservation was increased 

to its present size of 112 square miles (180 square kilometers) after a petition to congress 

from the Moapa Band of the Paiute.

In 1951, the Southern Paiute filed a claim with the Indian Claims Commission that 

was resolved in 1965 with a monetary settlement. Portions of the money from the settlement were invested in improvements to the reservation’s business enterprises. In 2011, 

there were 287 enrolled Tribal members with approximately 180 members living on 

the reservation. The total population was estimated at 425 residents (http://www.xeri.

com/Moapa/moapa.htm). The Southern Paiute have persevered over the years in the 

face of many obstacles and hardships associated with Euro-American occupation and 

settlement of the area and are actively working to preserve their heritage in publications 

detailing their history and culture.

Knowledge Gaps and Management Implications

Knowledge gaps concerning southern Nevada’s past, as derived from the archeological 

record, result from several sources. Chief among them are the extent of archeological 

survey coverage (the most common means of identifying cultural resources) and the 

nature of archeological survey itself. Approximately 783,756 acres (317,174.8 hectares) 

or 7 percent of the area under consideration have been surveyed for archeological resources (fig.8.1). Thus, a large portion of the area has received no coverage.

Because of the sparse nature of archeological survey coverage, basic inventories 

of cultural resources are needed. In particular, inventories that are not associated with 

planned development projects are desirable to expand surveyed lands and address gaps 

in coverage. Complete survey of the public lands in the study area is not a realistic 

goal owing to the cost involved. SNAP offices manage over 7 million acres—which 

is a huge area—to meet the “complete survey” expectation that would require over 

500man-years to survey with 30-meter transects at 2-miles per hour. In addition, cultural 

resource recording standards, as well as the sites themselves, will continue to change 

over time. A more realistic goal for regional-scale inventory would be to expand and 

improve the sample of lands that have been examined and sites that have been located 

and recorded. Because cultural resources represent finite, non-renewable resources that 

must be protected for the future, an important goal of inventory is to provide baseline 

information for measuring changes in the condition of sites through time.

In addition to the basic need for greater survey coverage, several studies have identified both specific and more general information gaps and have provided recommendations for addressing them. A major recommendation from the working group on the 

Information and State-of-the-Science Summary developed for the Ecosystem Health 

Assessment of Southern Nevada Project was to prepare a new Historic Context for the 

region that would structure and promote research important to the agencies. Such a 

context has been prepared, is currently in draft form, and is used in this review.

Other general recommendations from the working group include compiling regionwide data sets featuring both survey and excavation data. This data base would include 

layers suitable for GIS with information on plant communities, springs, surface geology, soils, and other pertinent resource information reflective of the close association 

between archeological sites and their environmental surroundings. The group also 

recommended producing “finder’s guides” to identify locations of existing collections 
58 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

of materials and records to assist researchers in locating available information on the 

regions’ cultural resources. More detailed discussions of needed research are found in 

the draft Prehistoric Context for Southern Nevada.

Managers in the area must take the limitations of archeological surveys into consideration when planning ground-disturbing projects to ensure that all sites are protected 

and free from damage. Managers in the area must take the limitations of archeological 

surveys into consideration when planning ground-disturbing projects to ensure that all 

sites are protected and free from damage as required, or that potential damage is mitigated by data recovery as mandated under Federal regulations.

Interpretive scenarios must also take into account the ongoing possibility that discovery of previously unknown resources will alter time lines and chronological schemes. 

The previously discussed recommendations made in the Draft Prehistoric Context for 

Southern Nevada address these issues and make recommendations to assist managers 

in dealing with the difficulties inherent in interpreting the archeological record. For a 

more in-depth discussion of the topics reviewed in this summary, see Chapter 8, Human 

Interactions With The Environment Through Time in “The Southern Nevada Agency 

Partnership Science and Research Synthesis—Science to support land management in 

Southern Nevada” (RMRS-GTR-303).

Key References

Ahlstrom, R.V.N.; Roberts, H. 2008. Prehistoric culture history. In: Lyon, J.D.; Roberts, H.; Ahlstrom, 

R.V.N.; Harper, C.; Eskenazi, S.; Davide, R.; Fowler, C.; von Till Warren, E. (preparers). Shared place: 

An archaeological survey of the Ash Meadows National Wildlife Refuge, Nye County, Nevada. HRA 

Archaeological Report No. 07-24. Las Vegas, NV: HRA, Inc., Conservation Archaeology. 396 p.

Ahlstrom, R.V.N.; Roberts, H. 2012. Puebloan period (A.D. 200-1300). In: Roberts, H.; Ahlstrom, R.V.N. 

(eds.). A prehistoric context for southern Nevada (draft). Las Vegas, NV: HRA, Inc., Conservation Archaeology and Carson City, NV: Gnomon Inc.: 115-164.

Clark, J.W. 1984. Prehistoric settlement in the Moapa Valley. Anthropological Papers No. 19. Carson City, 

NV: Nevada State Museum. 136 p.

de Dufour, K. 2011. [E-mail to Carol Raish]. March 01. On file at: U.S. Department of Agriculture, Forest 

Service, Rocky Mountain Research Station, Albuquerque Laboratory, Albuquerque, NM: RMRS-4853 

files.

Ezzo, J.A. 1995. A class I cultural resources survey for the Southern Nevada Water Authority treatment 

and transmission facility, Clark County, Nevada. Statistical Research Technical Series No. 55. Tucson, 

AZ: Statistical Research Incorporated, SRI Press. 276 p.

Ezzo, J.A. (ed.). 1996. A class I cultural resources survey of the Moapa and Virgin Valleys, Clark County, 

Nevada. Statistical Research Technical Series No. 58. Tucson, AZ: Statistical Research Incorporated, 

SRI Press. 209 p.

Ezzo, J.A.; Majewski, T. 1996. The cultural resources of the project area: prehistory, protohistory, and 

ethnography. In: Ezzo, J.A. (ed.). A class I cultural resources survey of the Moapa and Virgin Valleys, 

Clark County, Nevada. Statistical Research Technical Series No. 58. Tucson, AZ: Statistical Research 

Incorporated, SRI Press: 35-77.

Harper, C.; Ahlstrom, R.V.N.; Eskenazi, S. 2006. Introduction. In: Harper, C. (ed.). A room with a view: 

Data recovery of an early historical Rockshelter site located in the upper Moapa Valley, Clark County, 

Nevada. HRA Papers in Archaeology No. 5. Las Vegas, NV: HRA, Inc., Conservation Archaeology: 

1-14.

Inter-Tribal Council of Nevada. 1976. Nuwuvi: a Southern Paiute history. Salt Lake City, UT: University 

of Utah Printing Service. 177 p.

Kelly, I.T.; Fowler, C.S. 1986. Southern Paiute. In: D’Azevedo, W.L. (ed.). Great Basin. handbook of 

North American Indians. Vol. 11. Washington, DC: Smithsonian Institution Press: 368-397.

Lancaster, J.; Mouat, D.; Buck, P. (eds.). 2006. Information needs and state-of-the-science summary developed for the Ecosystem Health Assessment for Southern Nevada Project. Report on First Workshop—May 3-4, 2006. Reno, NV: Desert Research Institute. 31 p.

Lyneis, M.M. 1982. Prehistoric southern Nevada study units. In: An archaeological element for the Nevada Historic Preservation Plan. Submitted to Nevada Division of Historic Preservation and Archaeology, Carson City, Nevada. Las Vegas, NV: University of Nevada: 161-206.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 59

Lyneis, M.M. 1995. The virgin Anasazi, far western Puebloans. Journal of World Prehistory. 9 (2): 199-

241.

Roberts, H.; Ahlstrom, R.V.N. 2007. Native Americans in southern Nevada before 1492. In: Roberts, 

H.; von Till Warren, E.; Eskenazi, S. (preparers). Coyote named this place Pakonapanti: Corn Creek 

National Register Archaeological District, Desert National Wildlife Refuge, Clark County, Nevada. Las 

Vegas, NV: HRA, Inc., Conservation Archaeology: 27-47. Online: http://hraarchaeology.com/reports.

html [2012, Nov 09].

Roberts, H.; Ahlstrom, R.V.N. (eds.). 2012a. A prehistoric context for southern Nevada (draft). Las Vegas, 

NV: HRA, Inc., Conservation Archaeology and Carson City, NV: Gnomon Inc. 364 p.

Roberts, H.; Ahlstrom, R.V.N. 2012b. Recommendations. In: Roberts, H.; Ahlstrom, R.V.N. (eds.). A prehistoric context for southern Nevada (draft). Las Vegas, NV: HRA, Inc., Conservation Archaeology and 

Carson City, NV: Gnomon Inc.: 293-300.

Roth, B. 2012. Paleoindian and Archaic Periods. In: Roberts, H.; Ahlstrom, R.V.N. (eds.). A Prehistoric 

Context for S Nevada (draft). Las Vegas, NV: HRA, Inc., Conservation Archaeology and Carson City, 

NV: Gnomon Inc. 364 p.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].
60 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 61

Chapter 9

Preserving Heritage Resources Through 

Responsible Use of Southern Nevada’s Lands

Carol B. Raish

Executive Summary

Southern Nevada’s cultural resources (heritage resources) include archeological 

remains, sacred sites, historic sites, and cultural landscapes of significance to Native 

Americans and many other cultural groups. Locating, maintaining, and protecting these 

special places are part of the mandate of Nevada’s Federal and state agencies. This 

summary addresses Sub-goal 2.2 in the SNAP Science Research Strategy, which is 

“To preserve these resources through responsible use of southern Nevada’s lands” (see 

table 1.1). Cultural resources at risk, risk factors, and needed measures to protect them 

are discussed, focusing on non-destructive identification, preservation, and protection 

measures.

Cultural Resources at Risk

Nevada is one of the fastest growing states in the country. In southern Nevada, the 

population of Clark County (1,951,269) grew by 42 percent from 2000 to 2010. Inmigration from other states has contributed strongly to this growth, with newcomers 

often having little knowledge of the role and importance of the state’s history. These 

population growth trends have considerable influence on how the state preserves its 

past. Urban growth and development can lead to resource destruction as homes and 

businesses are built on previously undeveloped lands. Growing pressure on resources 

from increased recreation and the use of all-terrain vehicles (ATVs) has resulted in rising 

vandalism and illegal looting (collecting artifacts and/or excavating on an archeological site without a permit) on previously remote and inaccessible sites. Agency reports 

identify the following threats to heritage sites:

	 •	 Increasing visitation,

	 •	 Increasing use of public lands for permitted projects,

	 •	 Insufficient staffing and funding for cultural resource programs and law

enforcement,

	 •	 Looting and vandalism, and

	 •	 Urban sprawl and development.

Cultural Resource Protection Measures and Organizations

Federal agencies in southern Nevada use and recommend a number of measures to 

assist in protecting heritage resources: public education and outreach programs, cultural 

resource site monitoring, and law enforcement for cultural resources.
62 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Public Education and Outreach

Public education and outreach efforts range from preparing sites and structures to 

receive visitors with trails, signage, and other protection measures such as fencing, to 

active public involvement programs. Rapidly increasing recreation access requires public 

education concerning the importance and fragility of archeological and historic sites. 

Some of the most successful programs involve public participation, but they reach a 

more limited audience. Brochures and information kiosks also can be effective teaching 

tools and reach a wider audience. They are especially effective when they are attractive, 

current, and appropriately placed near the resource in question.

Several agencies have long-running, successful public involvement programs. An 

example of these is Adventures in the Past, which includes Project Archaeology, a national Bureau of Land Management (BLM) education program designed for teachers of 

upper elementary and mid-school students. The program trains teachers and provides 

curriculum materials for teaching students to value and care for their archeological and 

historic heritage. A Nevada-specific program, Preserve Nevada, is a non-profit organization dedicated to preservation of the state’s cultural, historic, and archeological heritage. 

Preserve Nevada works with the Public History program at the University of Nevada, 

Las Vegas, and provides the opportunity for graduate students to gain experience and 

training by working on the organization’s projects.

Other examples of creative outreach and education programs come from Lake Mead 

National Recreation Area, which has an active education and interpretive program featuring educational programs, field trips, and volunteer experiences. Education programs 

include not only cultural resource activities but also activities from other science programs for students and teachers. There is a Hispanic outreach program and a Hispanic 

community partnership program, which includes other Federal agencies that are part of 

SNAP, such as the BLM, U.S. Forest Service (USFS), Fish and Wildlife Service (FWS), 

and National Park Service (NPS). Specific examples of historic and cultural programs 

for students include “Hiking Through History,” which focuses on the Hoover Dam 

and the U.S. Government Railroad, and “Puzzle Pieces of the Past,” which focuses on 

archeological sites and artifacts.

Cultural Resource Site Monitoring

Monitoring the condition of heritage resources is an important part of agency responsibilities to their lands. Unfortunately, there are rarely sufficient law enforcement 

officers and staff to undertake comprehensive site monitoring on a realistic scale and 

time frame. Thus, in 2004, the Southern Nevada Agency Partnership (SNAP) Interagency 

Cultural Site Stewardship Team created the SNAP Cultural Site Stewardship Program 

(CSSP). The program is managed under a cooperative agreement with the University 

of Nevada-Las Vegas, Public Lands Institute (UNLV-PLI). The UNLV-PLI Program 

Manager provides a variety of services including recruitment of volunteer site stewards, standardized training, reporting of monitoring results to the appropriate Federal 

agency, and public outreach. The program is composed of volunteers who serve as site 

stewards to monitor at-risk sites for natural or man-made damage, which is reported to 

the responsible land manager. The volunteer site stewards monitor their assigned sites 

at least four times per year. To date, over 540 volunteer site stewards have been trained. 

Stewards have reported over 645 significant impacts that have resulted in criminal investigations, and have informed management actions including closing of unapproved 

roads, development of a Road Designation Plan, and removal of graffiti from rock art 

sites. The program has been very successful and has received several awards.
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 63

Law Enforcement for Cultural Resources

Federal agency law enforcement plays an important role in protecting archeological 

and historic remains from looting and vandalism. However, Federal heritage resource 

professionals believe that there are far too few agency law enforcement officers. Despite 

this shortage, there have been various successful prosecutions in recent years that have 

increased awareness of the problem of looting on archeological sites. BLM enforcement 

personnel have had some highly publicized and successful enforcement actions taken 

against organized thieves stealing archeological artifacts from the public lands. The 

USFS has successfully prosecuted an ARPA (Archaeological Resources Protection Act) 

case resulting in replacement of a petroglyph to its original location. The NPS had a successful prosecution of a man who was sentenced to time in Federal prison and ordered 

to pay restitution for defacing petroglyphs with paintballs in the Grapevine Canyon 

area of Lake Mead National Recreation Area. “This sentence comes as a result of the 

hard work of park rangers, special agents of the National Park Service Investigative 

Services Bureau, and the U.S. Attorney’s Office. We are pleased with the result,” said 

Bill Dickinson, superintendent of Lake Mead National Recreation Area. Despite such 

successes, there are still too few enforcement officers to protect the cultural resources on 

the extensive public lands of the state. “For every criminal caught in an ARPA violation, 

it is believed that many more violations go un-discovered, much less un-prosecuted.”

Non-Destructive Techniques for Identification of 

Archeological and Historic Remains

Because information on both surface and subsurface cultural resources is needed for 

management decisions, non-destructive techniques to uncover subsurface features can 

play an important role as part of the heritage resource toolkit. Geophysical surveying 

systems, such as ground penetrating radar, magnetometry, and soil resistivity surveying, non-invasively and non-destructively map subsurface features. These techniques 

are useful where excavation is undesirable, too costly, or otherwise not possible. They 

can assist managers in determining which areas to avoid during construction or other 

land-disturbing activities and which areas may require additional testing or excavation. 

However, these non-invasive methods require special equipment and training and may 

be costly. In addition, their land coverage rate is low owing to the nature of the methods 

and the time needed to implement them. Thus, they are mainly practical at small scales 

and are not cost-effective in replacing standard archeological survey techniques.

Knowledge Gaps and Management Implications

Southern Nevada’s heritage resources are at risk from a variety of factors including 

urban development and sprawl, and increased recreation use and access to previously 

remote, undisturbed areas. The Federal agencies that manage these vast acreages and 

irreplaceable resources remain understaffed and underfunded resulting in substantial 

management challenges. Nonetheless, they have implemented public education and 

outreach projects, volunteer site monitoring efforts, and law enforcement programs in 

attempts to protect the areas at risk. Continued research is needed to assess the effectiveness of these programs and develop additional means of cultural resource protection 

that can be implemented with limited funding.

When implementing projects, managers must address issues associated with protection and preservation of known sites as well as identifying and protecting any newly 

discovered sites. There are significant knowledge gaps relating to southern Nevada’s 
64 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

past, as derived from the archeological record. Only 783,756 acres (317,174.8 hectares), 

or 7 percent of the lands under consideration, have been surveyed for archeological 

resources (see fig.8.1); thus, a large portion of the area has received no survey coverage.

Because of the sparse nature of archeological survey coverage, basic inventories of 

cultural resources are needed. In particular, inventories that are not associated with 

planned development projects are desirable to expand the acres of surveyed lands and 

address gaps in coverage. Complete coverage of the public lands in the study area is 

not a realistic goal owing to the cost involved, because SNAP offices manage 7 million 

acres (2,832,799 hectares), a huge area to meet the “complete survey” expectation. 

That would be over 500 man-years to survey with 30-meter (32.8 yard) transects at 

2 miles (3.22 kilometers) per hour. In addition, cultural resource recording standards, 

as well as the sites themselves, will continue to change over time. A more realistic goal 

for regional-scale inventory would be to expand and improve the sample of lands that 

have been examined and of sites that have been located and recorded. Because cultural 

resources represent finite, non-renewable resources that must be protected for the future, 

an important goal of inventory is to provide baseline information for measuring changes 

in the condition of sites through time. For a complete discussion of topics in this executive summary, see Chapter 9, Preserving Heritage Resources Through Responsible 

Use of Southern Nevada’s Lands in “The Southern Nevada Agency Partnership Science 

and Research Synthesis—Science to support land management in Southern Nevada” 

(RMRS-GTR-303).

Key References

Jarvis, T.D. 2006. Cultural resources on the Bureau of Land Management public lands: an assessment and 

needs analysis. Washington, DC: National Trust for Historic Preservation. 36 p.

Lancaster, J.; Mouat, D.; Buck, P. (eds.). 2006. Information needs and state-of-the-science summary developed for the ecosystem health assessment for southern Nevada Project. Report on First Workshop—

May 3-4, 2006. Reno, NV: Desert Research Institute. 3p.

Lancaster, J.; Mouat, D.; Buck, P. (eds). 2007. Ecological health assessment in southern Nevada. Final 

Report –FAA010017 (GBCESU). Reno, NV: Desert Research Institute. Appendix 3:3-35-38.

Nevada State Historical Preservation Office (NVSHPO). 2004. Nevada comprehensive preservation plan 

2003. Onlineble: http://nvshpo.org/dmdocuments/HPPlan03.pdf [2012, Nov 15].

Nevada State Historic Preservation Office (NVSHPO). 2011. Preserve Nevada. Online: http://preservenevada.unlv.edu/ [2012, Nov 15].

Nevada State Historic Preservation Office (NVSHPO). 2012. Nevada comprehensive preservation plan 

2012. Online: http://nvshpo.org/dmdocuments/Plan_2013.pdf [2012, Nov 15].

Phillips, G. 2011. Footnotes on cultural site stewardship in Southern Nevada. Paper presented at the 2011 

Three Corners Conference. Las Vegas, NV: University of Nevada, Las Vegas.

Rowland, A. 2012. Personal communication. [E-mail to Carol Raish]. April 13. E-mail and handouts on 

file at: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Albuquerque 

Laboratory, Albuquerque, NM; RMRS-4853 files.

Shott, M.J. 1996. Introduction. In: Fagan, B.M. (ed.). The Oxford companion to archaeology. New York: 

Oxford University Press: 702-703.

Swain, T. 2007. Cultural resource damage on the public lands: what the statistics show. In: Hutt, S. (ed.), 

Tarler, D. (asst. ed.). Yearbook of cultural property law 2007. Walnut Creek, CA: Left Coast Press: 

201-220.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

USDI Bureau of Land Management. 2000. Strategic paper on cultural resources at risk. U.S. Department of 

the Interior, Bureau of Land Management. 17 p. Online: www.blm.gov/heritage/docum/00atriskpaper3.

pdf [2012, Nov 15].

USDI Bureau of Land Management. 2011. Heritage education. U.S Department of the Interior, Bureau of 

Land Management. [Enter website directly, link is not functional.] Online: http://www.blm.gov/wo/st/

en/res/Education_in_BLM/Learning_Landscapes/For_Teachers [2012, Nov 15].
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 65

USDI Fish and Wildlife Service. 2008. Protecting habitat and history: a 2008 progress report responding 

to Section 3(c) of Executive Order 13287, “Preserve America.” U.S Department of the Interior, Fish 

and Wildlife Service. 24 p.

USDI National Park Service. 2007. Southern Nevada Agency Partnership, Cultural Site Stewardship 

Program—Program Expansion and Steward Retention, Great Basin Cooperative Ecosystem Studies 

Unit Task Agreement No. J8R07070002. On file at: U.S. Department of the Interior, National Park 

Service, Lake Mead National Recreation Area, Boulder City, NV.

USDI National Park Service. 2011. Lake Mead National Recreation Area News Release: Arizona man 

sentenced to 15 months in prison for defacing Lake Mead National Recreation Area Petroglyphs. On 

file at: U.S. Department of Interior, National Park Service, Lake Mead National Recreation Area, 

Boulder City, NV.
66 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 67

Chapter 10

Recreation Use on Federal Lands in 

Southern Nevada

Alice M. McSweeney

Executive Summary

Providing for appropriate, diverse, and high quality recreation use of southern Nevada’s lands and ensuring responsible visitor use is an ongoing challenge for Federal 

agencies that manage much of this land (fig. 1.1). This chapter examines recreation on 

these Federal lands and addresses Sub-goal 2.4 in the SNAP Science Research Strategy 

(table 1.1). The demands for various types of recreational opportunities are discussed 

and the ways in which Federal agencies can provide quality recreational experiences 

without compromising resources are explored. Also discussed are current visitor use 

patterns and services provided by the designated recreation areas in southern Nevada.

Two significant factors influence recreationists and the natural resource base that 

supports outdoor recreation in Nevada. One is the fact that the State of Nevada ranks 

first in Federal land management (over 87 percent of Nevada’s land is administered by 

the Federal government); and the second is the highly urbanized population of the state 

(94 percent resided in urban areas in 2000). The rapidly growing population of southern 

Nevada results in an increase in recreational demands on the area’s public lands, and an 

associated shift in demographics brings changes in recreation tastes and preferences.

Outdoor Recreation Issues

The Nevada Division of State Parks (NDSP) developed the 2003 Statewide Comprehensive Outdoor Recreation Plan (SCORP), which provides review and study of recreation use within the entire state. The intention of the plan is to increase and improve the 

quality of outdoor recreation opportunities to meet the needs of the citizens of Nevada 

as well as the state’s many visitors. The dominant concern of respondents to the study 

was to keep Federal lands open for a wide variety of outdoor recreation activities while 

protecting the state’s natural resources.

Snap Interagency Recreation and Wilderness Planning

There are four Federal land management agencies in southern Nevada with eight 

congressionally designated resource areas. The Bureau of land Management (BLM) 

oversees Red Rock Canyon and Sloan Canyon National Conservation Areas (NCAs). 

The National Park Service (NPS) administers Lake Mead National Recreation Area 

(NRA). The United States Forest Service (USFS) manages Spring Mountains National 

Recreation Area (NRA). The United States Fish & Wildlife Service (USFWS) has the 

Desert National Wildlife Refuge Complex, which is comprised of four distinct National 

Wildlife Refuges (NWRs): Ash Meadows NWR, Desert NWR, Moapa Valley NWR, 

and Pahranagat NWR.
68 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

In 2002, the Federal managers of SNAP directed the four agencies (BLM, NPS, 

USFW, and USFS) to conduct interagency recreation management and to form the Interagency Recreation Team. The team’s vision is to provide interagency collaboration 

in the planning and management of recreational opportunities, facilities, and services 

while honoring the natural setting and complementing the quality of life in Southern 

Nevada. The SNAP Recreation Team initiated recreation visitor sampling on all SNAP 

lands using a single monitoring program based on the USDA FS National Visitor Use 

Monitoring (NVUM) program. Collectively, these NVUM reports provide comprehensive 

statistics on recreation use, visit characteristics, visitor spending, and the satisfaction of 

recreationists with recreation opportunities and resource conditions.

There were differences in the popularity of recreation choices across agencies, as 

management objectives, topography, and recreation resources differ from agency to 

agency. For example, on BLM lands there was a greater percentage that listed driving 

for pleasure and rock climbing as primary activities; water-based recreation was most 

prevalent on NPS lands; viewing wildlife was listed as the primary activity on USFWS 

lands; while camping was listed as the primary activity on USFS land. The overall rating 

of the four SNAP agencies indicated that the vast majority of visitors surveyed were at 

least “somewhat satisfied” with their visit.

Regional Trail Planning and Outreach

Partnerships between agencies (Federal, state, regional, and local), non-profits, 

businesses, individual citizens, and community partners played a critical role in the 

establishment and management of trails in southern Nevada. The proposed 113-mile 

Vegas Valley Rim Trail would serve to bind many land management areas, recreational 

destinations, municipalities, and agencies together.

The cities of Las Vegas and Henderson have completed open space plans designed 

to provide a ring of open space and wildlands that will encircle the Greater Las Vegas 

area and protect scenic, ecosystem, and cultural resources. Most of the corridor rests 

on BLM-managed lands, suggesting the need for continual coordination between the 

local community and Federal agency.

Knowledge Gaps and Management Implications

Southern Nevada’s rapidly increasing population has resulted in an increase in recreation demands on public lands, while an associated shift in demographics has altered 

recreation tastes and preferences. There are changes in visitor types to a more urban 

population who expect more expensive recreation enhancements.

These changes in the population impact the profile of recreation in the area and 

highlight the need for understanding the needs of a multi-cultural urban population. 

Additional information and management strategies are needed to meet future demands 

and trends. Funding of recreation areas and facilities with support staffing must be sufficient to keep pace with these increasing demands.

Southern Nevada’s growing population influences recreation activity on Federal 

lands and impacts the area’s natural resources. While these areas are beneficial to human population as healthy retreats from urban life, they are essential as habitat for many 

native species of flora and fauna. Therefore, it is imperative to consider the effects of 

increasing recreation demands on natural resources. Cooperation and collaboration between the four Federal land management agencies and with southern Nevada’s adjacent 

communities is necessary to achieve the goals of promoting natural and cultural resource 

stewardship while providing appropriate and sustainable recreation opportunities. For 

a complete discussion of topics in this executive summary, see Chapter 10, Recreation 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 69

Use on Federal Lands in Southern Nevada in “The Southern Nevada Agency Partnership 

Science and Research Synthesis—Science to Support Land Management in Southern 

Nevada” (RMRS-GTR-303).

Key References

Baca, M. 2010. Historical context for the “Great Circle.” Unpublished draft on file at: Outside Las Vegas 

Foundation, Las Vegas, NV.

City of Henderson. 2005. Open space and trails plan: adopted December 6, 2005. Henderson, NV: Community Development Department,. Online: http://www.cityofhenderson.com/community_development/open_space_and_trails_plan.php [2011, May 5].

Clark County. 2009. Las Vegas Valley perimeter open space plan--Phase 1: Open space locations and 

Vias Verdes report. Las Vegas, NV: Clark County Department of Air Quality and Environmental Management and the Department of Comprehensive Planning. 48 p. Online: http://www.clarkcountynv.

gov/Depts/comprehensive_planning/advanced_planning/Documents/LVVPerimeterPhase1Report.pdf 

[2012, Nov 16].

DeLoney, J.A. 2004. Nevada’s 2003 statewide comprehensive outdoor recreation plan – assessment and 

policy plan. Carson City, NV: Nevada Division of State Parks, Department of Conservation and Natural 

Resources. 288 p.

Holland, J.; Peterson, M.; Reardon, D.; Tanner, A.; White, E.; Yost, A. 2010. Understanding visitors to 

public lands in Clark County, Nevada. Southern Nevada Agency Partnership Recreation Team. Southern Nevada Visitor Use Monitoring. On file at: U.S. Department of Agriculture, Forest Service, Rocky 

Mountain Research Station, Albuquerque, NM. 4 p.

Reardon, D. 2011b. Personal communication. [E-mail to Alice McSweeney]. October 13. On file at: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, Albuquerque Laboratory, Albuquerque, NM; RMRS-4853 files.

Southern Nevada Agency Partnership (SNAP). 2002. Interagency recreation team charter. On file at: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, Albuquerque Laboratory, Albuquerque, NM. 6 p.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [Date accessed: June 5, 2012].
70 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 71

Chapter 11

Science-Based Management of Public Lands in 

Southern Nevada

Matthew L. Brooks and Jeanne C. Chambers

Executive Summary

Landmark legislation provides guiding principles for land management planning in 

southern Nevada and the rest of the United States. Such legislation includes, but is not 

limited to, the Forest Service Organic Administration Act of 1897 (16 U.S.C. 473-478, 

479-482 and 551), National Park Service Organic Act of 1916 (U.S.C. Title 16, Secs. 

1-4), Wilderness Act 1964 (P.L.88-577), National Environmental Policy Act of 1969 

(P.L 91-190), Endangered Species Act of 1973 (P.L. 91-205), National Forest Management Act of 1976 (P.L. 94-588), and Federal Land Policy and Management Act of 1976 

(P.L. 94-579). The acts establishing congressionally designated areas within southern 

Nevada, such as Lake Mead National Recreation Area, Spring Mountains National 

Recreation Area, and Desert National Wildlife Refuge, also contain guidelines for the 

management of these lands. These documents variously require preservation of natural 

and cultural resources and wilderness character, protection of species, and prevention of 

undesirable environmental effects from land management actions. These requirements 

must be met while allowing for multiple “uses” of certain public lands (e.g. recreation, 

ranching, resource extraction, renewable energy development, etc.) to the degree that 

they do not threaten protection, prevention, and restoration goals. Many considerations 

therefore come into play in the development and implementation of land management 

plans and actions. The planning process requires a balancing act that sometimes pits one 

need or priority against another. When priorities align, management actions can have 

multiple benefits. In some cases specific priorities can trump other needs and priorities 

and receive disproportionate consideration. Overall, the management of public lands is 

a very complicated and sometimes contentious process.

Science provides an objective way to help weigh quantifiable information and draw 

conclusions about the effects of past and potential future land management policies, 

decisions, and actions. When effectively integrated into adaptive management, sciencebased information can reduce uncertainties, increase knowledge, and improve decision 

making. However, the specific science information needed for effective management 

is often lacking or difficult to access or interpret. Science is typically reported in scientific journals as discrete units describing individual studies with other scientists as the 

primary audience. Translations of these studies and syntheses of multiple studies into 

formats that can be readily used in land management planning efforts are often lacking.

Identifying and articulating the highest priority science and research needs is one 

of the primary purposes of the Southern Nevada Agency Partnership (SNAP; http://

www.SNAP.gov) Science and Research Team (Turner and others 2009; Chapter 1). The 

SNAP Science and Research Strategy (Strategy) calls for a synthesis report to be written 

every 5 years summarizing the state of knowledge, information gaps, and management 

implications of scientific information as it relates to the SNAP Strategy goals (Turner 

and others 2009). This General Technical Report serves as the first SNAP Science and 
72 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Research Synthesis Report (Synthesis Report) commissioned by the Science and Research 

Team. The Synthesis Report is mostly based on information from the peer-reviewed 

scientific literature, and is itself peer reviewed and constitutes a new contribution to 

the scientific literature. This final chapter addresses Sub-goal 2.3, which is to “Manage current and future authorized southern Nevada land uses in a manner that balances 

public need and ecosystem sustainability,” and Sub-goal 2.5, which is to “Promote an 

effective conservation education and interpretation program to improve the quality of 

resources and enhance public use and enjoyment of southern Nevada public lands.” It 

summarizes information from the previous chapters on what scientific information is 

known currently and what remains largely unknown, and it discusses how science can 

be used to make future management decisions that balances public needs and ecosystem 

sustainability.

Current Scientific Understanding and Information Needs

Ecosystem stressors associated with human activities, wild horse and burro and 

livestock grazing, and altered fire regimes have been the traditional focus of land managers in southern Nevada. Concerns about invasive species emerged during the 1990s, 

and perhaps even greater concerns regarding climate change, energy development, and 

water development arose during the 2000s. The current challenge is to understand how 

to manage these many, and often interacting, stressors to maintain ecosystem sustainability. This task is more daunting today than it was only a few decades ago because 

of the rapidly expanding human population, the increase in the number of stressors of 

significant concern, and the need to address both public access and resource issues on 

Nevada’s public lands.

The effect of climate change on ecosystem sustainability is perhaps the greatest 

unknown stressor with respect to current management planning in southern Nevada. 

The science is clear that anthropogenic caused climate change is occurring on a global 

scale and that longer and more intense droughts and increased temperatures are becoming increasingly more likely in the deserts of southwestern North America (Chapter 2). 

However, the precise nature of these changes are not yet known and the scaled-down 

predictions necessary for determining the most effective management actions have 

yet to be developed. Also, it is not clear how these conditions will interact with other 

ecosystem stressors that land managers can potentially control. 

The current state of science can help tease out some of the most significant stressors 

threating ecosystem sustainability in southern Nevada (see Chapter 2). However, there 

is much more that remains unknown regarding these stressors and potential ecosystem 

responses. The sections that follow summarize these primary knowns and unknowns, 

and suggest research priorities for the major management topics in southern Nevada.

Water and Water Use

The hydrology of southern Nevada is characterized by regionally limited recharge 

areas within mountain ranges, and interbasin flow from adjacent regions. Discharge 

occurs through seeps and springs, evapotranspiration, subsurface flow out of the region, 

and pumping (Chapter 3). The Colorado River (Lake Mead) and its tributaries (the 

Muddy and Virgin Rivers), along with Las Vegas Wash, form the major fluvial systems 

in the area. Although recharge from precipitation can vary widely among years, large 

subsurface aquifers historically buffered inter-annual fluctuations in ground water levels 

across much of southern Nevada. This means that the discharge from springs and seeps 

was maintained for long periods of time, supporting locally endemic species and their 

habitat (Chapter 6). Accelerated rates of ground water pumping during recent decades 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 73

now affect discharge patterns threatening spring and seep ecosystems, and projected 

increases in pumping may pose even greater ecosystem threats in the future.

In order to effectively manage water resources in southern Nevada, it is important 

to understand future patterns of ground water recharge. Predictions of a warmer climate, potentially higher evapotranspiration rates, and more variable precipitation could 

dramatically alter ground water dynamics. An understanding of these potential future 

scenarios is critical to ensure that current planning decisions related to ground water 

pumping and water use do not adversely impact ground water resources or otherwise 

cause significant and potentially irreversible environmental degradation. (See Chapter 3 

for a detailed discussion of information needs related to water and water use in southern 

Nevada.)

Invasive Species

The concern associated with invasive species on wildlands in southern Nevada 

gained prominence following President Clinton’s Executive Order 13112 in 1999 and 

the development of a national strategy for management of this ecosystem stressor. 

At that time the science to support this mandate was not very extensive, as invasion 

biology had only emerged as a major branch of ecology during the 1980s. During the 

past few decades there has been a tremendous amount of new information generated 

regarding biological invasions worldwide.

In southern Nevada it is now clear that the main invasive plants of concern in upland 

areas are annual species, especially red brome (Bromus rubens) and Mediterranean splitgrass (Schismus spp.), which are associated with altered fire regimes. Riparian areas 

are most threatened by perennial plants, especially Tamarisk (Tamarix spp.), which can 

compete with native plants, degrade wildlife habitat, and potentially alter hydrologic 

and fire regimes. Aquatic plants are not yet recognized as major threats to the degree 

as their invasive analogs in terrestrial ecosystems. However, there are a few poised to 

invade southern Nevada that could become aquatic ecosystem transformers, including 

Eurasian water-milfoil (Myriophyllum spicatum) and giant salvinia (Salvinia molesta). 

Various non-native terrestrial animals are also of significant management concern in 

southern Nevada, ranging from ants, dogs, and cats, to free-roaming cows and equids 

(Chapter 4). The effects of species like ants and dogs and cats are related primarily to 

competition with or predation on native species, but habitat alteration by cows and 

equids is also a major concern. Non-native aquatic animals range from the quagga 

mussel (Dreissena rostriformis), American bullfrog (Rana catesbeiana), red swamp 

crayfish (Procambarus clarkia), to various fish species. Threats from these species 

include altered food web dynamics and predation on native species.

Perhaps one of the most significant unknowns relates to the ability to accurately 

predict future patterns of spread for existing invasives, establishment and spread of 

new invasives, and the relative and cumulative threats posed by all invasive species in 

southern Nevada. This information, and an understanding of the feasibility for controlling the different species, is critical for prioritizing management actions among the 

plethora of non-native and potentially invasive species in this region. (See Chapter 4 

for a detailed discussion of information needs related to invasive species management 

in southern Nevada.)

Fire History, Effects, and Management

It is generally understood that fire has been infrequent in most of southern Nevada 

since the last ice age, which ended approximately 10,000 years ago (Chapter 5). What is 
74 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

less recognized is that some landscapes have continuously experienced at least moderate 

fire frequencies during this time period. These include sagebrush, piñon-juniper, and 

mixed conifer ecosystems, and in these areas fire may be an important ecosystem process. 

However, the vast majority of the current southern Nevada landscape is dominated by 

blackbrush and lower elevation vegetation types that did not support frequent fire historically and where large and/or frequent fires are ecosystem stressors. Key fire management 

messages that can be derived from current science are that: (1) potential effects of fire 

should be evaluated in the context of ecosystem type, fire behavior characteristics, and 

site-specific characteristics (e.g., resistance to invasive species); (2) fire suppression is 

ultimately the most effective way to manage fire at middle and lower elevation where 

fire was historically infrequent, but wildland fire use or fire surrogates may be appropriate under certain circumstances at higher elevations; and (3) the post-fire rehabilitation/

restoration tools that are currently being used at middle to lower elevations appear to 

be ineffective or poorly evaluated (Chapter 5). 

Information is needed on both long-term ramifications of fire in middle and upper 

elevation vegetation types (i.e., blackbrush and above), and post-fire management of 

lower elevation vegetation types dominated by creosotebush (Larrea tridentata) and 

saltbush (Atriplex spp.). In all future fire studies, the potential influence of climate 

change should be considered to place the results in the context of climate projections 

for the next decades through the end of the current century. (See Chapter 5 for a detailed discussion of information needs related to fire history, effects, and management 

in southern Nevada.)

Species of Conservation Concern

Aside from the desert tortoise (Gopherus agassizii), which has been studied more 

than any other species in southern Nevada, relatively little is known about the life 

history characteristics and specific habitat requirements of most species in this region 

(Chapter 6), including the species covered under the Clark County Multiple Species 

Habitat Conservation Plan. Research has often focused on mitigation strategies to protect 

sensitive species without a full understanding of the life history and ecophysiological 

constraints on the species and the stressors that are causing their declining status.

With so many unknowns associated with the many species of concern in southern 

Nevada, it is a challenge to prioritize which species should be the focus of scientific 

research and which questions should be addressed. The default is often to focus on 

species that agencies have specific legal requirements to protect (e.g., Federally listed). 

Development of effective conservation plans requires an understanding of the life history 

characteristics, habitat requirements, and specific stressors affecting the listed species. 

These plans may initially lack the desired level of detail. However, critical information 

needs can be identified in the planning process and new research projects coupled with 

habitat and population monitoring can be used to develop an effective adaptive management program. (See Chapter 6 for a detailed discussion of information needs related to 

species of conservation of concern in southern Nevada.)

Maintaining and Restoring Sustainable Ecosystems

The overarching objective for land managers in southern Nevada is to maintain and 

restore sustainable ecosystems that are resilient to disturbance and resistant to invasion 

(Chapter 7). The ecosystems types within southern Nevada differ significantly in both 

their environmental characteristics and dominant stressors and, consequently, in their 

resilience to disturbance and resistance to invasive species. In order for restoration and 

management strategies to be effective, they must account for these differences. A useful 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 75

decision support framework based on ecosystem resilience and resistance distinguishes 

among: (1) protection from current and future stressors; (2) preventive management 

actions designed to increase resilience and resistance of areas with declining ecological conditions; and (3) restoration activities following disturbance or other ecosystem 

degradation (table 7.1). This framework allows for customized guidelines for each of 

the major ecosystems types in southern Nevada (table 7.2). An integrated and consistent 

assessment of southern Nevada ecosystems and their relative resilience and resistance 

can be used to prioritize management and restoration activities using this framework. 

Monitoring programs designed to track ecosystem changes in response to both stressors 

and management actions can be used to increase understanding of ecosystem resilience 

and resistance, realign restoration and management approaches, and implement adaptive 

management.

Cross-cutting information needs for restoration and management of southern Nevada’s diverse ecosystems include a better understanding of the factors that determine 

resilience and resistance and of the interacting effects of the region’s stressors. They 

also include knowledge of the environmental conditions required for establishment and 

persistence of native plant species and methods for their restoration. (See Chapter 7 for 

a detailed discussion of information needs related to maintaining and restoring sustainable ecosystems in southern Nevada.)

Human Interactions with the Environment through Time and Preserving 

Heritage Resources

Southern Nevada has been continuously inhabited by humans at least since the 

end of the last ice age (Chapter 8). This period marks the shift from a more mesic and 

temperate climate to the more arid desert climate that exists today. During most of the 

post ice age Holocene (i.e., the last 12,000 years), human occupation was characterized by small nomadic bands that migrated seasonally following resources needed for 

subsistence. During the last few thousand years, larger settlements emerged that were 

associated with a move towards more agricultural societies in the riverine bottomlands. 

The first Europeans travelled to southern Nevada in the late 1700s, and by the middle 

1850s settlers were steadily migrating into the region along the Old Spanish Trail (later 

the Mormon Road) and displacing Native Americans from their agricultural, foraging, 

and hunting lands. Settlers also brought with them horses and livestock that were having 

significant effects on the landscape as early as the 1800s, and these stock animals have 

been continuously present through to the present (Chapter 2). 

Population levels moved upward with the construction of Hoover Dam in the 1930s, 

but really increased substantially during the past few decades resulting in urban sprawl, 

increased development within public lands, and increased visitation to remote areas 

of southern Nevada (Chapter 9). This has resulted in the loss of cultural sites through 

development, looting, and vandalism. Public education, law enforcement, and monitoring of cultural sites are widely recognized as ways to minimize damage to these sites. 

However, agency resources are generally insufficient to address all of these needs.

The major remaining information gap is the limited extent of archeological survey 

coverage; only 7 percent of Southern Nevada has been surveyed, primarily within the 

Las Vegas Valley and associated with development projects (Chapter 8). A complete 

survey for the region is not realistic, but additional targeted surveys that expand and 

improve the sample of lands examined would go a long way towards improving the 

baseline information in the region. More comprehensive links between archeological 

sites and their environmental settings would increase understanding of potential interactions between humans and ecosystem conditions. Also, continued research is needed to 

evaluate the effectiveness of public education and outreach, volunteer site monitoring, 
76 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

and law enforcement programs in achieving the objectives of reducing damage to and 

loss of cultural sites. (See chapters 8 and 9 for a detailed discussion of information 

needs related to human interactions with the environment through time and preserving 

heritage resources in southern Nevada.)

Recreation Use on Federal Lands

The vast majority of lands are open to human use in southern Nevada. The burgeoning 

human population is increasing the use of these lands for recreational purposes, creating a very difficult challenge for Federal land managers (Chapter 10). Also, the human 

population is becoming more urban and multi-cultural, resulting in potential changes 

in recreational patterns that will require flexibility in current management approaches. 

To plan for these changes, land managers need information about how these changing 

demographics may affect the types and patterns of recreational use of public lands. (See 

Chapter 10 for a detailed discussion of information needs related to recreation use on 

federal lands in southern Nevada.)

The Role of Science in Land Management

Management that balances public need and ecosystem sustainability is informed by 

the science information in this Synthesis Report. The goal of ecosystem sustainability 

has its origins in legislation mentioned at the beginning of this chapter, and subsequent 

national policies that call for natural resources, and by inference to the ecosystem processes that sustain them, to be preserved unimpaired for future generations. However, 

land managers must balance the goal of ecosystem sustainability with other goals derived 

from other laws and national policies associated with recreation, resource extraction, 

and other land uses that collectively constitute the land management context of southern 

Nevada. Although science often plays a major role in the initial legislation and policy 

development and can form the foundation of initial planning goals and objectives, subsequent science produced through targeted research studies and monitoring for status and 

trend of resources has the greatest influence on deciding when a management response 

is warranted or when established management objectives may need to be modified 

(fig. 11.1).

Objectives should be written with specific science-based, objective, and measurable 

standards in mind. For example, allowing livestock grazing up to a limit of x percent 

vegetation biomass consumption based on a sliding scale that takes into account recent 

climatic conditions and other potential interacting stressors. Objective standards greatly 

simplify the process of monitoring and decision making because they are relatively 

unambiguous (fig. 11.1). The problem is that science is often insufficient to justify 

specific standards, and therefore standards are based on general scientific theory and 

are relatively subjective (for example, allowing grazing practices that do not negatively 

affect the health, productivity, and diversity of plant communities, which is subjective 

and hard to monitor). Subjective standards require more complicated monitoring and 

generally make decision making more difficult and controversial.

Once management plans are implemented, monitoring plans that are specifically 

coupled with management objectives can help land managers monitor the status and 

trend of their ecosystem resources and determine if management responses or modifications of management objectives are warranted (fig. 11.1). With the advent of the 

information age and ability to archive and share data remotely, there has been a move 

towards more standardized monitoring methods to facilitate large scale analyses across 

multiple land management agency units. However, these standard methods are often 

not ideally suited for evaluating management objectives that are designed for smaller 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 77

landscapes and their local land management contexts. Land managers must understand 

these potential limitations and choose their monitoring and data management methods 

carefully to ensure that they will give them the scientific information necessary to effectively evaluate their management objectives and management actions.

The Role of Science in Education

This Synthesis Report serves as an outreach document to inform stakeholders and the 

general public about the major ecosystem stressors, and natural, cultural, and recreational 

resources in southern Nevada. It also provides valuable information on management 

alternatives.

An educated populace makes it easier for land managers to communicate science-based 

management with the public and should ultimately streamline the approval processes for 

land management plans. As mentioned above, science information is often written by 

scientists for scientists and science products are often not ideal for communication with 

the general public. There is, therefore, a need for science-based objective summaries 

of key land management topics that clearly distinguish between what is scientifically 

known and what is more generally derived from professional opinion and cultural influences. The mode of information delivery should also be varied to capture a wide range 

of audiences (e.g. print, radio, television, websites, and social media).

Key References

Abella, S.R. 2008. A systematic review of wild burro grazing effects on Mojave Desert Vegetation, USA. 

Environmental Management. 41:809-19.

Abella, S.R. 2009. Post-fire plant recovery in the Mojave and Sonoran Deserts of North America. Journal 

of Arid Environments 73:699-707.

Abella, S.R.; Newton, A.C. 2009. A systematic review of species performance and treatment effectiveness 

for revegetation in the Mojave Desert, USA. In: Fernandez-Bernal, A.; De La Rosa, M.A. (eds.).Arid 

environments and wind erosion. Hauppauge, NY: Nova Science Publishers, Inc.: 45-74

Figure 11.1–The role of science in the management of Federal lands in southern Nevada.
78 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013

Ahlstrom, R.V.N.; Roberts, H. 2012. Puebloan Period (A.D. 200-1300). In: Roberts, H.; Ahlstrom, R.V.N. 

(eds.). A prehistoric context for southern Nevada (draft). Las Vegas, NV: HRA, Inc., Conservation Archaeology and Carson City, NV: Gnomon Inc.: 115-164.

Bainbridge, D. A. 2007. A guide for desert and dryland restoration. Washington, DC: Island Press. 391 p.

Breshears, D.D.; Myers, O.B.; Meyer, C.W.; Barnes, F.J.; Zou, C.B.; Allen, C.D.; McDowell, N.G.; Pockman, W.T. 2009. Tree die-off in response to global change-type drought: mortality insights from a 

decade of plant water potential measurements. Frontiers in Ecology and the Environment. 7:185-189.

Brooks. M.L. 2011. Effects of high fire frequency in creosotebush scrub vegetation of the Mojave Desert. 

International Journal of Wildland Fire. Online: http://dx.doi.org/10.1071/WF10140.

Brooks, M.L. 2009. Spatial and temporal distribution of non-native plants in upland areas of the Mojave 

Desert. In: Webb, R.H.; Fenstermaker, L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, E.V.; Miller, D.M. 

(eds.). The Mojave Desert: Ecosystem processes and sustainability. Reno, NV: University of Nevada 

Press: 101-124.

Brooks, M.L.; Chambers, J.C. 2011. Resistance to invasion and resilience to fire in desert shrublands of 

North America. Rangeland Ecology and Management. 64:431-438.

Brooks, M.L.; D’Antonio, C.M.; Richardson, D.M.; Grace, J.B.; Keeley, J.E.; DiTomaso, J.M.; Hobbs, 

R.J.; Pellant, M.; Pyke, D. 2004. Effects of invasive alien plants on fire regimes. BioScience. 54:677-

688.

Brooks, M.L.; Lusk, M. 2008. Fire management and invasive plants: a Handbook. United States Fish and 

Wildlife Service, Arlington, VA: 27 p.

Brooks, M.L. and R.A. Minnich. 2006. Southeastern deserts bioregion. In: Sugihara, Neil G.; van Wagtendonk, Jan W.; Shaffer, Kevin E.; Fites-Kaufman, JoAnn; Thode, Andrea E. (eds.). Fire in California’s ecosystems. Berkeley: The University of California Press: 391-414.

Brooks, M.L.; Pyke, D. 2001. Invasive plants and fire in the deserts of North America. In: Galley, K.; Wilson, T. (eds.). Proceedings of the invasive species workshop: The role of fire in the control and spread of 

invasive species. Fire Conference 2000: The First National Congress on Fire Ecology, Prevention and 

Management. Miscell. Publ. No. 11. Tallahassee, FL: Tall Timbers Research Station. 

DeLoney, J.A. 2004. Nevada’s 2003 statewide comprehensive outdoor recreation plan – assessment and 

policy plan. Carson City, NV: Nevada Division of State Parks, Department of Conservation and Natural 

Resources. 288 p.

Engel, C.E.; Abella, S.R. 2011. Vegetation recovery in a desert landscape after wildfires: influences of 

community type, time since fire and contingency effects. Journal of Applied Ecology 48, 1401–1410.

Ezzo, J.A. (ed.). 1996. A class I cultural resources survey of the Moapa and Virgin Valleys, Clark County, 

Nevada. Statistical Research Technical Series No. 58. Tucson, AZ: Statistical Research Incoporated, 

SRI Press. 209 p.

Faunt, C.C.; D’Agnese, F.A.; O’Brien, G.M. 2010. Hydrology. In: Belcher, W.R.; Sweetkind, D.S. (eds.). 

Death Valley regional groundwater flow system, Nevada and California--Hydrogeologic framework 

and transient groundwater flow model. Professional Paper 1711. U.S. Department of the Interior, U.S. 

Geological Survey: 137-159.

Harper, C.; Ahlstrom, R.V.N.; Eskenazi, S. 2006. Introduction. In: Harper, C. (ed.). A room with a view: 

Data recovery of an early historical rockshelter site located in the upper Moapa Valley, Clark County, 

Nevada. HRA Papers in Archaeology No. 5. Las Vegas, NV: HRA, Inc., Conservation Archaeology: 

1-14.

Harrill, J.R.; Gates, J.S.; Thomas, J.M. 1988. Major ground-water flow systems in the Great Basin region 

of Nevada, Utah, and adjacent states. U.S. Geological Survey Hydrologic Investigations Atlas HA694-C. 2 sheets. Reston, VA: U.S. Department of the Interior, U.S. Geological Survey. 1:1,000,000; 

[Projection unknown]; colored. 2 sheets. Online: http://pubs.er.usgs.gov/publication/ha694C. [Date accessed: Oct 26, 2012].

Harrill, J.R.; Prudic, D.E. 1998. Aquifer systems in the Great Basin region of Nevada, Utah, and adjacent 

states. Professional Paper 1409-A. U.S. Department of the Interior, U.S. Geological Survey. 66 p.

Harris, J.A.; Hobbs, R.J.; Higgs, R.; Aronson, J. 2006. Ecological restoration and global climate change. 

Restoration Ecology. 14:170-176.

Hereford, R.; Webb, R.H.; Longpré, C.I. 2006. Precipitation history and ecosystem response to multidecadal precipitation variability in the Mojave Desert region, 1893-2001. Journal of Arid Environments. 67: 13-34.

Holland, J.; Peterson, M.; Reardon, D.; Tanner, A.; White, E.; Yost, A. 2010. Understanding visitors to 

public lands in Clark County, Nevada. Southern Nevada Agency Partnership Recreation Team. Southern Nevada Visitor Use Monitoring. On file at: U.S. Department of Agriculture, Forest Service, Rocky 

Mountain Research Station, Albuquerque, NM. 4 p.

Jarvis, T.D. 2006. Cultural resources on the Bureau of Land Management public lands: an assessment and 
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-304. 2013 79

needs analysis. Washington, DC: National Trust for Historic Preservation. 36 p.

Loarie, S.R.; Duffy, P.B.; Hamilton, H.; Asner, G.P.; Field, C.B.; Ackerly, D.D. 2009. The velocity of 

climate change. Nature. 462:24-31.

Lovich, J.E.; Bainbridge, D. 1999. Anthropogenic degradation of the southern California desert ecosystem 

and prospects for natural recovery and restoration. Environmental Management. 24:309-326.

Lyneis, M.M. 1995. The virgin Anasazi, far western Puebloans. Journal of World Prehistory. 9 (2): 199-

241.

McKinley, R.A.; Brooks, M.L.; Klinger, R.C. [In press]. Fire history of southern Nevada. Open File Report. Sioux Falls, SD: U.S. Geological Survey. 62 p.

National Invasive Species Council. 2008. 2008-2012 National invasive species management plan. 35 p. 

Online: http://www.invasivespeciesinfo.gov/council/mp2008.pdf. [2012, Oct 29].

Nevada State Historic Preservation Office (NVSHPO). 2012. Nevada comprehensive preservation plan 

2012. Online: http://nvshpo.org/dmdocuments/Plan_2013.pdf [2012, Nov 15].

Notaro, M.; Mauss, A.; Williams, J.W. 2012. Projected vegetation changes for the American Southwest: 

combined dynamic modeling and bioclimatic-envelope approach. Ecological Applications. 22:1365-

1388.

Planert, M.; Williams, J.S. 1995. Ground water atlas of the United States, Segment 1, California, Nevada. 

Hydrologic Investigations Atlas 730-B. U.S. Department of the Interior, U.S. Geological Survey. 28 p.

Pyke, D.A. 2011. Restoring and rehabilitating sagebrush habitats. In: Knick, S.T.; Connelly, J.W. (eds.). 

Greater sage-grouse: ecology and conservation of a landscape species and its habitats. Studies in Avian 

Biology. Berkeley, CA: University of California Press: 531-548.

RECON (Regional Environmental Consultants, Inc.). 2000. Final Clark County Nevada multiple species 

habitat conservation plan and environmental impact statement. Prepared for Clark County Administrative Services. 550 p. plus appendices.

Scoppettonni, G.G. 1993. Interactions between native and nonnative fishes of the upper Muddy River, 

Nevada. Transactions of the American Fisheries Society. 122:599-608.

Shafroth, P.B.; Cleverly, J.R.; Dudley, T.L.; van Riper, III C.; Stuart, J.N. 2005. Control of Tamarix in 

the western United States: implications for water salvage, wildlife use, and riparian restoration. 

Environmental Management. 35:231–246.

Shott, M.J. 1996. Introduction. In: Fagan, B.M. (ed.). The Oxford companion to archaeology. New York: 

Oxford University Press: 702-703.

Smith, S.D.; Charlet, T.N.; Fenstermaker, L.F.; Newingham, B.A. 2009. Effects of global change on Mojave Desert ecosystems. In: Webb, R.H.; Fenstermaker, L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, 

E.V; Miller, D.M. (eds.). The Mojave Desert: ecosystem processes and sustainability. Las Vegas, NV: 

University of Nevada Press: 31-56.

Southern Nevada Agency Partnership (SNAP). 2002. Interagency recreation team charter. On file at U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station, Albuquerque Laboratory, Albuquerque, NM. 6 p.

Swain, T. 2007. Cultural resource damage on the public lands: what the statistics show. In: Hutt, S. (ed.), 

Tarler, D. (asst. ed.). Yearbook of cultural property law 2007. Walnut Creek, CA: Left Coast Press: 

201-220.

Turner, K.; LaVoie, A.M.; Ronning, C.J.; Sharp, R.M.; Palmer, C.J.; Miller, J.M. 2009. SNAP Science and 

Research Strategy (Strategy). Southern Nevada Agency Partnership. Online: http://snap.gov/upload/

SNAP-S-R-Strategy-2009r.pdf. [2011, April 6].

U.S. Fish and Wildlife Service (USFWS) 2011. Revised recovery plan for the Mojave population of 

the Desert Tortoise (Gopherus agassizii). Sacramento, CA: U.S. Department of the Interior, Fish and 

Wildlife Service, Region 8, Pacific Southwest Region.. 246 p. Online: http://www.fws.gov/nevada/

desert_tortoise/documents/recovery_plan/RRP%20for%20the%20Mojave%20Desert%20Tortoise%20

-%20May%202011.pdf. [2012, Oct 30].

Weigand, J.; Rodgers, J. 2009. Active restoration for the Mojave Desert. In: Webb, R.H.; Fenstermaker, 

L.F.; Heaton, J.S.; Hughson, D.L.; McDonald, E.V.; Miller, D.M. (eds.). The Mojave Desert. Las Vegas, 

NV: University of Nevada Press: 378-409.

Wirth, T.A. and D.A. Pyke. 2007. Monitoring post-fire vegetation rehabilitation projects—A common 

approach for non-forested ecosystems: U.S. Geological Survey Scientific Investigations Report 2006-

5048. 36 p. 




The U.S. Department of Agriculture (USDA) prohibits discrimination against its 

customers, employees, and applicants for employment on the bases of race, 

color, national origin, age, disability, sex, gender identity, religion, reprisal, and 

where applicable, political beliefs, marital status, familial or parental status, 

sexual orientation, or all or part of an individual’s income is derived from any 

public assistance program, or protected genetic information in employment 

or in any program or activity conducted or funded by the Department. (Not all 

prohibited bases will apply to all programs and/or employment activities.) For 

more information, please visit the USDA web site at: www.usda.gov and click on 

the Non-Discrimination Statement link at the bottom of the page.

To learn more about RMRS publications or search our online titles:

www.fs.fed.us/rm/publications

www.treesearch.fs.fed.us

Federal Recycling Program Printed on Recycled Paper