## (

S u

U

. New M A 

## Manc o ( Astraga l

5-Y e

u mmary

Photo:



### . S. Fish a n M exico Ec o

A lbuquer q

J u



## o s Milkv e l

us humi l

e ar Revi e

and Ev a

Robert Sivin s



### n d Wildlif e

o lo g ical S e q ue, New M

u l y 2011 

## e tch l

limus )

e w

a luation

s ki



### fe Service

e rvices O f M exico fice

### 5-YEAR REVIEW Mancos milkvetch/ Astragalus humillimus

1.0 GENERAL INFORMATION

1.1 Reviewers

Lead Regional Office: Southwest Regional Office, Region 2 Susan Jacobsen, Chief, Threatened and Endangered Species, 505-248-6641 Wendy Brown, Endangered Species R ecovery Coordinator, 505-248-6664 Maggie Dwire, Recovery Biologist, 505-248-6663 Julie McIntyre, Recovery Biologist, 505-248-6507

Lead Field Office: New Mexico Ecologica l Services Field Office Eric Hein, Terrestrial Branch Chief, 505-761-4735 Thetis Gamberg, Fish and W ildlife Biologist, 505-599-6348 Laura Hudson, Vegetation Ecologist, 505-761-4762

1.2 Purpose of 5-Year Reviews:

The U.S. Fish and Wildlife Service (Service or USFWS) is required by section 4(c)(2) of the Endangered Species Act (Act) to co nduct a status review of each listed species at least once every 5 years. The purpose of a 5-year review is to evaluate whether or not the species’ status has changed since it was listed (or since the most recent 5-year review). Based on the 5-year review, we recommend whether the species should be removed from the list of endangered and threatened species, be changed in status from en dangered to threatened, or be changed in status from threatened to endangered. Our original lis ting as endangered or threatened is based on the species’ status considering the five threat factors described in section 4(a)(1) of the Act. These same five factors are considered in any subsequent reclassification or delisting decisions. In the 5-year review, we consider the best available scientific and co mmercial data on the species, and focus on new information available since the spec ies was listed or last reviewed. If we recommend a change in listing st atus based on the results of the 5-year review, we must propose to do so through a separate rule-making pro cess including public review and comment.

1.3 Methodology used to complete the review

The U.S. Fish and Wildlife Service (Service) con ducts status reviews of species on the List of Endangered and Threatened Wildlife and Plan ts (50 CFR 17.12) as required by section 4(c)(2)(A) of the Endangered Species Ac t, as amended (Act) (16 U.S.C. 1531 et seq .). Public notice for this status review was published in the Federal Register on April 23, 2007 (72 FR 20134), requesting information on the status of Astragalus humillimus (Mancos milkvetch). Written comments were received from the Navajo Nation Department of Fish and Wildlife (2009), and a long-term demographic study report was received from the State of New Mexico Forestry Division (2008).3 This review was a collaborative effort compri sed of biologists from the Service’s Region 2 Regional Office and New Mexico Ecological Se rvices Field Office, the Region 6 Western Colorado Field Office, and the State of New Mexi co Forestry Division. Several botanical and species experts in Colorado and New Mexico were contacted in spring of 2010 for updated information. Robert Sivinski, Botanist for th e State of New Mexico Forestry Division, was contracted through a section 6 gran t to gather relevant informati on and prepare a draft of this review. The final review and recommended cla ssification were prepared by the New Mexico Ecological Services Field Office.

1.4 Background

The purpose of this 5-year re view is to ensure that Astragalus humillimus has the appropriate level of protection under the Ac t. The review documents a de termination by the Service of whether the status of the species has changed si nce the time of its listing. The review also provides updated information on the current th reats, ongoing conservation efforts, and the priority needs for future conservation actions.

1.4.1 FR Notice citation announcing initiation of this review: 72 FR 20134: April 23, 2007

1.4.2 Listing History:

Original Listing FR notice: 50 FR 26568 Date listed: June 27, 1985 Entity listed: Species, Astragalus humillimus Classification: Endangered, without critical habitat

1.4.3 Associated rulemakings: None.

1.4.4 Review History: A 5-year review was initiated on November 6, 1991, (56 FR 56882) for all species listed before 1991, but no document was prepared for this species.

1.4.5 Species Recovery Priority Numb er at start of 5-year review: 2. The recovery priority number is 2, indicating a high degree of threat, a high recovery potential, and the listed entity is a species.

1.4.6 Recovery Plan or Outline

Name of plan or outline: Mancos Milkvetch ( Astragalus humillimus ) Recovery Plan Date issued: December 20, 1989 Dates of previous revisions: The recovery plan has not been revised.4 2.0 REVIEW ANALYSIS

2.1 Application of the 1996 Distinct Population Segment (DPS) policy

The Distinct Population Segm ent policy does not apply to Astragalus humillimus because it is not a vertebrate animal.

2.2 Recovery Criteria

2.2.1 Does the species have a final, approved recovery plan? Yes. Although there is a final recovery plan, it doe s not reflect up-to-date information on the species’ biology, nor does it address all five listing factor s that are relevant to the species. When the recovery plan was finalized in 1989, limited available data made it impossible to quantify habitat requiremen ts with enough precision to establish further recovery criteria. Thus, while criteria for recove ry, downlisting, and delis ting were established, they are difficult to quantif y and have not been met.

2.2.1.1 Does the recovery plan contain objective, measurable criteria? No The recovery plan lists one main goal which is to remove Astragalus humillimus from the Federal list of endangered a nd threatened species by managing the essential habitat to sustain natural populati ons in the wild. Th e delisting criteria within the recovery plan are meant to demonstrate (1) long-term stability of populations and habitat through at least 10 years of mon itoring, and (2) continued assurances that threats have been alle viated for all pres ently known populations, and 75 percent of any plants a nd habitat has been discovered.

The criteria given for downlisting A. humillimus to threatened are summarized below, including known details on their current status.

1) Census and map all known populations.

Known populations were surveyed a nd mapped for Navajo Nation, Bureau of Land Management, and State of New Mexico lands during the 1980s; monitoring plots for these three agenci es were last surveyed in 2008 (see Section 2.3.1.2). Colorado Natural Her itage Program has census and map data for this species on Ute Mountain Ut e tribal lands, but no new information has been collected sinc e the late 1980s.

2) Use this data to develop formal documen tation of long-term mineral, oil, gas, and energy development potential in the area.

Navajo Nation, Bureau of Land Manage ment, and State of New Mexico lands are managed to protect and minimize impacts to federal, state, or agency listed species regarding any mineral or energy development (see #3 below on habitat management plans). Each of these thr ee agencies will determine the need to consult with the Service based on wh ether the proposed project location5 overlaps with known populations previous ly surveyed and mapped. It is unknown if the Ute Mountain Ute tribe us es their census and map data (last prepared by Colorado Natural Heritage Pr ogram in the late 1980s) to manage for the protection of this species if an d when mineral or energy development is proposed.

3) Develop a habitat management plan to administer mineral development in the area and to provide for th is species’ welfare.

A habitat management plan with conservation recommendations was completed by the Nature Conservancy for Navajo Nation lands in 1992, but enactment of the provisions within the plan is unknown. Navajo Nation classifies this species as Group 2, which is defined as a species or subspecies whose prospects of survival or recruitment is in jeopardy. Bureau of Land Management classifies this plant as a sensitive species (SS) found in the Hogback Area of Critical Environmenta l Concern (ACEC). State of New Mexico and Ute Mountain Ute lands do not have management plans, even though the State of New Mexico consider s this species to be “endangered” and Colorado State classifies this species as “rare.”

4) Establish permanent long-term mon itoring plots at population sites.

All systematic plot monitoring ende d in 2008 on State of New Mexico and Bureau of Land Management lands; only observational visits continue to be performed. The Navajo Nation esta blished two permanent plots in 1991 located on the Hogback geologic formation; however, only one of these plots was relocated, remapped, and surveyed in 1991. The status of all known populations and known potential hab itat on Navajo Nation lands was summarized in a 2009 letter to the Service. We are not aware of any longterm monitoring plots on Ut e Mountain Ute tribal lands.

The recovery plan also contains an imple mentation table of prioritized actions to

recover A. humillimus . These actions address the st ated recovery goal, but cannot be quantified. Of the 13 actions recommended, 3 have been implemented or are ongoing, including:

1) enforcement of existing laws; 2) research into the species eco logical requirements; and 3) research regarding seed biology.

Although the downlisting criteria and pr ioritized actions provide guidance for recovery, they do not offer benchmarks for measuring progress towards recovery or specifically address current threats. Even though th e original listing factors remain relevant to this species, climate change (specifically severe drought) and off-road vehicle use are now recognized as additional threats to this species’
recovery.6 2.3 Updated Information and Current Species Status

2.3.1 Biology and Habitat

2.3.1.1 New information on the species’ biology and life history

Morphology, reproductive biology, and phenology Astragalus humillimus is a diminutive, tufted pere nnial growing in clumps up to 30 centimeters (cm) (12 inches [in]) across with a dense crown of persistent spiny leaf stalks; no other mat-forming Astragalus species has persistent, subspinescent petioles (Barneby 1964). Stems are up to 1 cm (0.4 in) long and are crowded with leaves up to 4 cm (1.6 in) long (Barneby 1964). Flower branches support 1 to 3 lavender/purplish flowers with a conspicuous lighter-colored spot in the throat of the corolla tube (Service 1989). Astragalus humillimus flowers in late April and early May (Service 1989). Root systems pr oliferate about 7 cm (3 in) below the surface (Service 1989). Larger plants ma y produce over 100 flowers in a growing season and fruits mature by mid-June (Servi ce 1989). The fruit is egg-shaped and laterally compressed measuring about 4.5 millimeters (mm) (0.2 in) long and 2 mm (0.1 in) in diameter (Barneby 1964), a nd each produces 4 to 9 seeds (Service 1989). In New Mexico, monitoring results revealed that it takes two growing seasons for seedlings to mature with flow ering into the third or fourth year as compared to other species of Astragalus , which typically take one growing season to bloom (New Mexico State Forestry Division 2008).

Pollination biology Astragalus humillimus plants produce viable fr uit by outcrossing and selfpollination (Tepedino 2002). Flowers of rare plants, including A. humillimus

, often require pollination by native bees to produce seeds (Tepedino 2002). Possible pollinators of A. humillimus were studied in 1989 by the Bee Biology and Systematics Laboratory for the Navajo Nation; a full list is provided in the Habitat Management Plan for Navajo Na tion (House and Engelking 1992). They found the most common visitors were two members of the bee family Megachilidae: Osmia titusi and O. sculleni . Honey bees and butterflies, including the painted lady butterfly ( Vanessa cardui ), were also noted as potential pollinators (Service 1989). Fruit set is generally good and no pollinator limitations were detected (Tepedino 2002).

Habitat, geology, and plant community This species occurs on sandstone substrat e ledges and mesa tops in cracks or shallow bowl-like depressions (tinajas) that accumulate sandy soils and rainfall (Service 1989; New Mexico State Forest ry Division 2008). Populations are found along the Colorado Plateau subdivision of th e Great Basin Desert of northwestern New Mexico and southwestern Colora do within pinyon-juni per woodland and desert scrub communities (Dick-Peddie 1993) . Potential habitat corresponds to rimrock outcrops of the Point Lookout and Cliffhouse members of the Mesa Verde sandstone series with flat or gen tly sloping surfaces at an average elevation7 of 1,854 meters (m) (5,650 feet [ft]) (Service 1989). This species is confined to large sheets of exfoliating whitish-tan colored sandstone (New Mexico State Forestry Division 2008) alongside Fraxinus anomala (single leaf ash), Brickellia microphyla var. scabra (scabrous bricklebush), Cercocarpus intricatus (small leaf mohagany), and Ipomopsis roseata (rosy ipomopsis) (S ervice 1989). Overall cover is very low (less than five percent) , and resource competi tion for all of these species is minimal (Service 1989). At a broader landscape scale, dominant plant associates are Achnatherum hymenoides (Indian ricegrass) , Gutierrezia sarothrae (broom snakeweed) , Yucca angustissima (narrow leaf yucca)

, and Artemisia tridentata (big sagebrush) (Service 1985).

Fecundity and genetic variability At the time of listing, a limited amount of information was available about the species’ life history and ha bitat requirements. While the 1989 Recovery Plan identified specific information needs, few studies have been conducted to increase our knowledge. Many Federal permits have been issued for collection and study of this species since the early 1980s, but only a few of these research projects have been completed. One final report i nvolved research on several populations of Astragalus from Arizona and New Mexico

, including A. humillimus , which were assessed for morphological, re productive, genetic, and ecological differences (Allphin et al. 2005). Resu lts suggest that two endangered taxa, A. humillimus and the closely related A. cremnophylax var. cremnophyla x (sentry milkvetch), appear to have low fecundity (fertility). The au thors suggest that environmental fluctuations would not likely be a contributing factor to their small population size; instead, low fecundity and reduced genetic variability is more likely due to inbreeding depression (All phin et al. 2005). Reduced fitness is commonly found within the Astragalus genus where many species persist in small, highly restricted populations a nd are endemic to particular geologic formations (Karron 1989).

Mycorrhizal associations The Arboretum at Flagstaff, an ongoing Federal permittee, is conducting studies

on A. humillimus seed biology and ecological requirements (Service 2010). Seed germination trials from the Arboretum’s early work show that this species is difficult to keep in cultivation and is se nsitive to over or under-watering; no seeds germinated in the first trial with s eeds collected from 1993 (Center for Plant Conservation 2010). Other preliminary resu lts found that soils collected from the Hogback ridge sandstone were low in arbuscular mycorrhizal fungi inoculum potential; these soils were just slightly higher in inoculant capacity than sterile potting soil (Haskins and Murray 2009). Mycorrhizal fungi are found in root tissues and increase the efficacy with whic h plants harvest soil minerals necessary for plant growth (Graham et al. 2006). Because Astragalus species are generally mycorrhizal dependent, this lack of myc horrhizae could be detrimental to the long-term persistence of A. humillimus (Haskins and Murray 2009). Another listed species in the same study, the sentry milkvetch ( A. cremnophylax var. cremnophylax ), which is genetically related to A. humillimus and found in nearby8 Grand Canyon National Park

, had much higher mychorrhizal inoculant capacity in occupied soils (Haskins and Murray 2009). More studies are underway to better understand the implications of this fungi-soil relationship.

2.3.1.2 Abundance, population trends , demographic features, or demographic trends

Astragalus humillimus is a narrow endemic known onl y from the Four Corners region of New Mexico, San Juan County, and adjacent Montezuma County, Colorado. Species distribution closely follo ws a narrow band of Mesozoic (Point Lookout and Cliff House) sandstone al ong a 10-mile section of the Hogback geologic formation (Service 1989). Prior to 1989, there were a total of 13 known populations with 3 of these located on Ut e Mountain Ute tribal lands in Colorado (Service 1989). Since the completion of the recovery plan in 1989, the Colorado populations have not been monitored. Ne w plots were installed for Bureau of Land Management (BLM) and State of New Mexico lands starting in 1990. Only Navajo Nation found their 13 previously known populations, along with one new population, allowing for some long-term co mparisons to past population numbers.

SPECIFIC STUDY AREA STATUS AND TRENDS

COLORADO

Ute Mountain Ute: In 1987, th ere were four populations of A. humillimus in Colorado on Ute Mountain Ute tribal la nds; surveys were done by employees of the Colorado Natural Heritage Program (Colorado Natural Heritage Program 2010). In 1987, the total estimated sum of individuals from the four populations was 4,421 with total occupied habitat about 43 hectares (ha) (106 acres [ac]); approximately 0.2 ha (0.5 ac) per populat ion (Colorado Natural Heritage Program 2010). Since 1987, access has been restri cted, and no new information about these populations has been pr ovided to the Service.

NEW MEXICO

Bureau of Land Management: In 1990, fi ve plots were installed on a rim of sandstone at Slickrock Flats on the no rthwest BLM boundary with Navajo Nation (New Mexico State Forestry Division 2008). These plots were read annually until 1999, then in 2002 and 2008 with an informal site visit in 2010. Plots were located on specific habitat (a single tinaja or crack segment) over 3.1 ha (7.6 ac). Initially, density (total plant counts), mo rtality, and recruitment were recorded. However by 1993, it became apparent that single plants were coalescing into single larger masses. Thus, new measurem ents were developed to determine at a minimum “population vigor” (total plant cover) while still counting new seedling density.Sever 1988 a live p l due t o Sand s to ha v 2008) 1997 t whic h (Wes t seedl i stabl e numb

Resul t comb i

cover (Figu r

Figur e each o

were r provi d

State o place d from class i Fores t e mortality o

a nd 1989. O l ant counts.

o the nature o

s tone cracks

v e higher ad u

. Starting i n t o a low of z h was the se c t ern Region a i ngs (four se , possibly i n ers, but cov e

t s of total pl i ned reveale value in 20 0

r e 2).

e 1

. Astraga l

o n New Mexi c

r ead during J u d ed by New M

o f New Me x d at the Slee p 1988 found i ndicating a
t ry Division o ccurred pri o O n average, t

Some tinaj a

o f these sm a are deeper a

u lt populati o

n 1990, seed l

z ero plants i n

c ond year o f

a l Climate C edlings tota l

n creased po p

e r estimates

ant cover in d the highe s 0 8 (92 cm 2 )

l us humillim u

c o State (N M

u ne of each y e M exico State F

x ico: Origi n p ing Rocks p 5 4 percent o high level o 2008). A p

9 o r to the ins t t here was 6 0

a s experienc

a ll exposed d

a nd more pr o

o ns over tim e l ing density

n 2002 (Fig u f a severe an d

enter 2010)

. l were foun d
p ulation of a d

and seedlin g
squared ce n

s t cover of 2

, with the co m

u s seedling de M S) and Bure a

e ar from 199 0 F orestry (20 0

n ally in 198 8

p opulation o

o f the popul a

f reproducti o

r olonged dr o t allation of p 0 percent m o

c ed a 100 pe r d epressions v

o tected fro m

e (New Me x varied fro m

u re 1). No m d ongoing d r

. By 2008, o d ). During t h d ults was o b
g counts we r

n timeters (c m

, 354 cm 2 du r

m plete loss o

e nsity (total s e

a u of Land M a 0 to 1999, th e 0 8) and figur e

8 , a one hect a

o n State of N

a tion was in on at that ti m

o ught occur r p lots; droug h

o rtality base d

r cent mortal

v ersus sand s

m

moisture l o

x ico State F o

m

a high of 7

m onitoring w

r ought for t h

o nly two pl o h e 2010 inf o b served b as e

r e not cond u

m 2 ) for all fi v

r ing 1993, a

o f plants in t

e edlings per y

a nagement ( B

e n 2002 and 2

e developed b y

a re monitor i N ew Mexico

the seedlin g

m e (New M e

r ed in late 1 9 h t years wer e d on dead v e ity rate pos s

s tone cracks

. o ss and appe

o restry Divi s 1 individual s

w as done in 2 h is region

o ts had any

o rmal site vi s

e d on 2008 p

u cte d

.

v e BLM pl o

a nd the lowe s t wo of the p l

y ear) for five B LM) lands. 2 008. Data
y Service (2 0

i ng plot was lands. Res u g and juveni l

e xico State 9 88 through e

e rsus

s ibly

. ared

s ion s in 2 003

s it, a
p lant

o ts

s t l ots

plots Plots

0 10).

u lts l e age1989. plot, s

were s infor m abov e

Resul t densi t high o (Figu r had a of ad u numb

Resul t comb i

cover b y 20 0

avera g b e a d seedl i

Figur e New M read d u New M By 1990, a

s o five new p

s urveyed an n

m al site visit

e for BLM.

t s were sim i
t y was high e

o f 324 indiv i

r e 1). By 2 0 high of 303

u lts was obs e ers, but cov e

t s of total pl i ned reveale value in 19 9 0 8 (Figure 2
g ing 665 c m d ecrease in o i ng counts w

e 2. Astraga l M exico State

u ring June o f M exico State F a ll the steel p p lots of vari a

n ually from in 2010. P l

i lar to the B L

e r overall. F i duals in 19 9 0 08, only on e

plants. Du r

e rved with s

e r estimates

ant cover in d the highe s 9 6 (640 c m 2 ) 2 ). Howeve r

m 2 by 2008. D

verall plant s

w ere not con d

l us humillim u (NMS) and B f each year fr o F orestry (20 0

10 p lot posts w e

a ble sizes w 1990 until 1 l ots were m e

L M plots de s

r om 1990 t o 9 7 to a low o

e plot had a n

r ing the 201 0

o me recent d and seedlin g

c m 2 for all f

s t cover of 4

, ) with the c o

r , plant cove r D uring a 20

s based on 2 0 d ucted.

u s total cover B ureau of La n

o m 1990 to 1 9 0 8) and figur e e re missing f as installed o 1 999, then i n

e asured in t h

s cribed abo v

o 2008, seed l

o f four plant

n y live plan t 0 informal s i d ead plants b
g counts we r

f ive State o f

, 443 cm 2 du r

o mplete loss r remained r 10 informal 008 numbe r

(c m 2 ) for pla n

n d Managem e 9 99, then 20 0

e developed b f rom this or i over 2 ha (5

n 2002 and 2 h e same ma n

v e except th a l ing density s in 1996 a n t s (n=34); in i te visit, a s t b ased on 20 0

r e not cond u

f New Mexi c

r ing 1993, a of plants i n

r elatively hi g

site visit, t h

r s, but cover

n ts found in f

e nt (BLM) la n 0 2 and 2008. b y Service (2 0 i ginal monit o ac). These 2 008 with a n

n ner as desc r

a t seedling varied fro m

n d eight in 2 0

1997, this p t able popula t 0 8 plant

u cte d

.

c o plots

a nd the lowe s

n one of the p g h for two p h ere appeare d

estimates a n

f ive plots eac h

n ds. Plots w e

Data provid e 0 10). o ring plots

n

r ibed

m

a 0 02
p lot
t ion

s t p lots lots d to

n d

h on

e re

e d by11 Navajo Nation: The Navajo Natural Heritage Program has 13 historical population records for A. humillimus . In 2007 and 2008, the Program Botanist, Daniela Roth, resurveyed known populations as well as potentia l habitat in the Hogback and Palmer Mesa areas. When surveys were conducted in 2007 and 2008, 13 populations were found. However, pl ants at one of these 13 locations appeared to be extirpated, and one population was newly discovered, but contained only a single individual. Total plant counts in known populations clearly indicate a precipitous decline (Table 1).

Table 1. Historical records and recent survey results summarized for Astragalus humillimus (Navajo Natural Heritage Program 2008a).

Site 1980s ( approximate ) counts 2007 or 2008 counts Notes

1 500 35 2 200 115 All age classes 3 500 28 90% juveniles 4 200 14 5 4,200 11 6 1,700-2,000 100 Oil & gas activity 7 ++ ++ *BLM ACEC 8 50 8 9 a few 12 10 - - Cannot relocate 11 100s 35 12 17 7 13 30 20 14 1 Newly found.

TOTAL: ~7,500 TOTAL: 386

*Bureau of Land Management Area of Critical Ecological Concern ++ Monitoring data in New Mexico State Forestry Division 2008 final report.

Historical records indicated that during the 1980s, total known population size was approximately 7,600 individual plants on Navajo Nation lands. By 2008, less than 400 plants were found in 12 populati ons and only 2 of the 12 populations (17 percent) had more than 50 live plants (Navajo Natural Heritage Program 2008a; Navajo Nation Department of Fish a nd Wildlife 2009). Ot her 2008 results found the majority of plants remaining were sma ll to medium in size; dead plants were observed in almost all locations; plants were widely scattered and only a very small fraction of the habita t was occupied; and 82 per cent of the plants were ranked as fair to poor based on low plan t numbers, plant condition, and landscape context (Navajo Natural Heritage Program 2008a; Navajo Nation Department of Fish and Wildlife 2009).12 Other Astragalus humillimus surveys: In 2006, presence/absence data was collected for this species along a 25.8 kilo meter (km) (16 mile [mi]) right-of-way for the Segment A, Shiprock Substation, Navajo Transmission Project which included a small section of BLM land; no A. humillimus were found (Ecosphere Environmental Services 2006).

In 2007, Western Area Power Administrati on contracted a botanical survey for the existing Lost Canyon-Shiprock and Ka yenta-Shiprock Transmission Lines, approximately 45 km (28 mi) across Na vajo Nation, New Mexico State, and Bureau of Land Management lands; 71 A. humillimus were found (56 live and 15 dead) all on BLM land (Ecosystems Environmental Services 2007).

In 2008, Ecosphere Environmental Services performed A. humillimus presence/absence surveys on five oil and gas wells (Navajo #5, Navajo B #2, Navajo C #5, Mesa Gallup Unit #15, and Na vajo G #222). All wells are located on Navajo Nation lands along the Point Lookout Sandstone mesa, and only the Navajo B #2 well location and associated pipeline had plants onsite. Two main populations were recorded with a total count of 109 plants (Ecosphere Environmental Services 2008b). As of 2011, BLM stated that most of the wells have been plugged and abandoned, and because the work required a biological monitor on site, the plants should ha ve been protected (Kendall 2011).

There are major individual site differences with regard to A. humillimus seedling density and mature plant cover. Desp ite these differences, it appears that maximum population development and dens ity occur on larger, relatively flat surfaces with numerous cracks and tinajas th at accumulate soil and rainfall (New Mexico State Forestry Division 2008). This observation is supported by distinct site differences found between the BLM a nd State of New Mexico plots. The BLM plots are all within a larger sand stone surface containing many sizable tinajas; whereas, the State of New Mexico plots are smaller sandstone islands with fewer depressions for soil and mo isture deposition (New Mexico State Forestry Division 2008).

Astragalus humillimus germination and initial seeding survival appear to be positively related to the death of older plan ts and subsequent moisture availability (New Mexico State Forestry Division 2008) . This availability may be due to increased precipitation events aboveground in conjunction with moisture/nutrient releases belowground from the loss of adu lt root biomass. Seedling establishment and adult cohort mortality cycles may also be related to shade limitations (foliar canopy is reduced) and space limitations (sites become available for germination). Mortality of older plants (five to seven years of age) appeared to increase during and possibly after drought years, but dry conditions were also often associated with spider mite infestations, which c ould hasten mortality (New Mexico State Forestry Division 2008).13 2.3.1.3 Genetics, genetic variation, or trends in genetic variation

Even though specific genetic studies are needed, inferences can be made from research on several rare Astragalus species in Arizona a nd New Mexico. Results from Allphin et al. (2005) sugge st that two endangered taxa, A. humillimus and the closely related A. cremnophylax var. cremnophyla x, appear to have low fecundity (fertility) and environmental fl uctuation is not likely a contributing factor to small population size (Allphin et al. 2005). Moreover, one of two populations of A. cremnophylax var. cremnophyla x (North and South Rim of Grand Canyon, AZ) was found to be geneti cally depauperate (lacking genetic diversity) indicating a bottleneck caused by historic trampling on the South Rim, and was less related gene tically to the North Rim population than other taxa within this species complex (Allphin et al. 2005). These results suggest that inherent low fecundity and potential bottl enecks due to isolation could negatively affect A. humillimus populations through loss of gene tic variation as reported for the closely related species A. cremnophylax var. cremnophylax.

2.3.1.4 Taxonomic classification or changes in nomenclature

Taxonomic classification of A. humillimus has not changed since the recovery plan was finalized in 1989.

2.3.1.5 Spatial distribution, trends in sp atial distribution or historic range

The distributional range of A. humillimus has not changed since the recovery plan was finalized in 1989. Although there is suit able habitat within Ute Mountain Ute tribal lands, we are not sure if any new surveys have been done due to lack of communications from the tribe.

2.3.1.6 Habitat or ecosystem conditions

Climate Astragalus humillimus is a narrow endemic with very specific habitat needs in shallow tinajas, and appears to be sens itive to ecosystem conditions affected by changes in climate, particularly pr ecipitation. The recent drought (2002-2003) spanning southwestern North America was anomalously dry, but is different from the 1950s drought in having unusually high temperatures (higher annual maximum and minimum temperatures as well as higher average summer temperatures) (Breshears et al. 2005). The IPCC (2007) predicts the average annual temperature in the southwest regi on of the United States could rise by about 2.5 to 3.9 o C (4.5 to 7 o F) during th is century. This in creasing rate of 0.56 o C (1.0 o F) every 14 years has already been surpassed in Arizona since the 1970s, and New Mexico is just slightly be low this rising temperature rate (Lenart et al. 2007).Hydr o less s n is sub south w 1970 s 2008) with a towar (Enq u
Spati a preci p 2008) partic u preci p to oc c Cent e in) w a Mean well b

Figur e from t h (2010 )

At th e 1989) (Par m Lena r result o logic trend s

n owpack, a n stantiated ( P

w estern stat e

s (Parmesan

. New Mex

a bout 54 per c d drie r , and

u ist and Gor i

a l heterogen e p itation, is e x

. To look a t

u lar to a na r p itation in S h

c ur, has bee n

r 2010). In

a s recorded w

annual pre c b elow the lo n

e 3. Average h e Western R )

.

e population

. Growing s

m esan 2007)

r t et al. 2007

in decrease d s in the Sout h

n d earlier sp r P armesan an d

e s show a lo n and Galbrai t ico precipit a

c ent of the s 5 percent w i i 2008).

e ity of drou g

x tremely va r t precipitati o

r row endemi h iprock, Ne w

n 157 mm (6

2002, no pr e

w hich is the

c ipitation si n

n g-term ave r

annual preci p R egional Cli m

level, A. hu m

s easons are b including t h ; Enquist an d flowering

14 h west are le

r ing melt an d d Galbraith 2

n g-term tre n t h 2004; Ud

a tion chang e

s tate trendin g i th no disce r

g ht as defin e

r iable in the

o n more loc a c such as A.

w Mexico, a n .2 in) from 1

e cipitation w third lowes t

n ce the drou g

r age (Weste r

p itation total s

m ate Center ( 2

m illimus is a b ecoming lo h e southwest

d Gory 200 8 and reprod u ss clear exc e d runoff in t h 2004; Udall

n d of increa s d all and Bate

e s show mor e g toward we

r nable chan g

e d by tempe r

state of Ne w

a lly can rev e

humillimus

. a n area in w h

1 926 to 200 0

w as recorde d
t level meas u g ht (2003-2 0

r n Regional

s (inches) fro m 2 010) and fig u

a spring flo w

o nger and w a

(Cayan et a 8 ). Earlier s

u ction, and b e pt when co n h e Intermo u and Bates 2

s ed precipit a

e s 2007; En q

e variation t h tter conditi o g e between 1

r ature, and p

w Mexico ( E

e al site speci f

. Average a n h ich A. humi 0 (Western R d , and by 20 0

u red since 1 0 07) was 97

Climate Ce n

m

1931 to 2 0

u re develope d

w ering speci

a rmer in ma n

a l. 2001; Eas

oil moistur e ecause this p n sidering s n

u ntain West s 2 007), yet th

a tion since t h
q uist and Go r

h an temper a

o ns, 41 perc e 1 991 and 20 0

p articularly E nquist and G

fic trends

n nual llimus is kn o R egional Cl i 0 4, 33 mm ( 926 (Figure mm (3.8 in )

n ter 2010).

0 07. Data ret r d by Service

es (Service

n y regions terling 200 2

e stress woul
p lant has a n ow;

s tates

e h e

r i

a ture,

e nt 0 5

G ori

o wn i mate 1.3 3). )

,

r ieved

2 ;

d15 limited distribution, we would predic t a substantial population reduction associated with a long-term warming trend.

At the microsite level, A. humillimus is found in small depressions on sandstone substrates where cracks and fissures accumulate sands and form small soil pockets that support root systems that can extend 3 to 8 cm (1.1 to 3.1 in) below the surface (Service 1989, New Mexico St ate Forestry Division 2008). These distinct sites are affected by the slightes t change in precipitation and temperature, and A. humillimus appears to respond quickly to the change. Study results indicated that this plant fare d better in habitats consisting of deep cracks in the bedrock where depth provides shade and lower temperatures, increasing the amount and length of time when moisture is available to plants, particularly during drought years (New Mexico State Forestry Division 2008).

Increases in herbivorous insects, both native and nonnative, are also predicted with changes in climate, and will advers ely affect many species (Enquist and Gori 2008). This herbivory was documented since the 1980s for A. humillimus during many of the drier years. During the drought of 2002 and 2003, an infestation of spider mites entirely covering many mature plant clumps often contributing to mortality of already stressed plants (S ervice 1989, Sivinski and Knight 2001, New Mexico State Forestry Division 2008). Sp ider mites feed on the leaf surface and these injured leaves are shed more quic kly, and eventually the whole plant may die. Even a minor spider mite infest ation can have a significant impact on a plant's health.

Since the documented decline of A. humillimus is concurrent with drier years and the severe drought of the early 2000s, we woul d expect that if a change in climate led to increased severity or frequency of drought, it woul d have a negative impact on the species. Narrow endemics, like A. humillimus , often have very specific habitat requirements. Because plants are unable to move, a change in climate that causes mortality that exceeds reproduction and recruitment, could lead to the extirpation of A. humillimus . We believe the 2008 low population numbers are likely caused by cumulative losses since th e 1980s due to several notable drought periods for this region. Continued long- term effects on their population numbers may not be entirely evident until dro ught conditions cease to exist. Some recovery, particularly for new seedlings, has occurred but appears to be triggered by both adult plant mortality and increased moisture events.

2.3.2 Five-Factor Analysis

2.3.2.1 Present or threatened destruction, modification, or curtailment of its habitat or range – Factor A:

Major threats to A. humillimus continue to be from su rface disturbanc e activities associated with energy exploration a nd development, and transmission line construction and maintenance (Service 1989; House and Engelking 1992; Bureau16 of Land Management 2007; Navajo Na tion Natural Heritage Program 2007, 2008a, and 2008b; Navajo Nation Departme nt of Fish and Wildlife 2009). Threats to habitat or range summarized below include: (1) energy exploration and development; (2) transmission lines; and (3) off-road vehicles.

Energy Exploration and Development: The majority of known occupied and potential A. humillimus habitat is located on the Na vajo Nation lands. Most of this habitat is located on Palmer Mesa and the Hogback areas covering approximately 16,187 ha (40,000 ac) on Na vajo Nation lands. These areas contain active and plugged oil and gas we lls, including numerous roads associated with these activities. Navajo Nation a nd BLM lands contain significant deposits of oil and natural gas, and the development of these en ergy resources in the Four Corners Basin continues to increase (E nergy, Minerals, and Natural Resources Department 2008). Nearly all known and potential A. humillimus habitat may be affected by natural gas or oil exploration and development. Most damage occurs after vehicles and heavy equipment drive over and crush individual plants as well as break apart sandstone areas that contain tinajas, which are required for A. humillimus seedling establishment (Navajo Na tion Department of Fish and Wildlife 2009).

Since listing, several reports documented negative effects to A. humillimus populations

. In 2007, the Navajo B Well #2 well plug and abandonment operation either crushed (11 pl ants) or killed (6 plants) all of the plant population within the disturbed area on west Palmer Mesa; damage was caused by industry vehicles driving off the designated well pad and existing road (Navajo Natural Heritage Program 2007; Bureau of Land Management 2007). The vehicles and heavy equipment also fractured sandst one, compacted soils, and created a new spur road that bisected part of this A. humillimus population (Navajo Natural Heritage Program 2007). In addition to this disturbance, but unrelated to the well activities, a pipe and electrical lin e were found nearby above ground with no history of installation; one plant appeared to have died from the line with eight live plants remained next to or under the line (Bureau of Land Management 2007).

In 2008, a separate incident occurred in th e same general vicinity of Navajo B Well #2 where heavy equipment drove over several A. humillimus plants (they survived), but the surrou nding habitat was extensivel y damaged (Navajo Natural Heritage Program 2008b). Several days later, two backhoes were found parked two miles away still encrusted in heavy mud. The impacts started nearby the well site, but also occurred alongside several access roads and involved tracks to other well sites within a two-m ile radius. Significant sc raping of the soil surface occurred, and the constructi on of an earthen berm and trenching for a pipeline was also recorded by Navajo Nation and BLM law enforcement (Navajo Natural Heritage Program 2008b). Due to the wet conditions at the time, severe backhoe17 damage occurred over two miles of sands tone and tinaja habitat essential to A. humillimus populations (Navajo Natural Heritage Program 2008b).

As of 2011, BLM has no new oil and gas development in the Hogback ACEC since 2008, only maintenance for existing we lls (Kendall 2011). Presently, there are 7-8 active oil wells (one gas well) in the entire ACEC with over 30 plugged and abandoned wells, thus oil and gas de velopment is nonexistent at this time (Kendall 2011).

The Desert Rock Energy Project (DRE P) has been proposed by the Bureau of Indian Affairs (BIA) and is within the range of this species. The biological assessment for the project found that A. humillimus will be exposed to and adversely impacted by the deposition of c ontaminants from two other existing power plants as well as DREP (Ecosphe re Environmental Services 2008a). The significance of these impacts to A. humillimus is unknown at this time because the DREP consultation has not been completed.

Astragalus humillimus populations and their habi tat have been negatively impacted by crushing from vehicles and equipment, direct removal and destruction from energy-rela ted activities, and indirect effects of unauthorized traffic using roads constructed by oil a nd gas companies. Oil and gas well construction has resulted in a variety of unauthorized roads, multiple pipelines, and small but enduring piles of wast e, all of which further degrade A. humillimus habitat over the larger lands cape. Also, some habitat damage has been reported by Navajo Nation from vandalism associat ed with theft of copper cables running between oil wells (Navajo Natural Heri tage Program 2008b). Thus, we believe oil and gas development remains a severe threat to the species and will likely increase in the foreseeable future.

Transmission Lines: Transmissi on lines have likely impacted A. humillimus populations because potential habitat and recently surveyed plants have been found along several major transmission line corridors (Ecosphe re Environmental Services 2007). A large population of approximately 1,000 plants was bisected by two major transmission lines, the Gl en Canyon-Shiprock and the CurecantiShiprock transmission lines, which were constructed in 1962 and 1963 prior to the National Environmental Policy Act taki ng effect (50 FR 26570). Immediate impacts were complete scraping of topso il and vegetation directly underneath the power line, thus it is unknow n how many plants may have been destroyed. Since that time, any plants underneath and near by the power line have been driven over by either maintenance vehicles or off-road recreation vehicles. At the time of listing in 1985, no repopulation had occurr ed, but the most recent survey done by Western Area Power Administration found 71 plants over approximately 45 km (28 mi) of Navajo Nation, State of New Mexico, and BLM lands; total area surveyed was 138 ha (342 ac) (Ecosphe re Environmental Services 2007).18 The 1992 Habitat Management Plan (HMP) for A. humillimus describes the extensive transportation system within and surrounding Navajo Nation lands. This system, consisting of roads and corridors, is being developed by BIA, Navajo Nation, private corporations, and individuals, with little coordination between these entities on the protection of rare and endangered species’ habitat (House and Engelking 1992). The HMP al so mentions the increased demand for utilities, which has le d to disturbance of A. humillimus habitat. For example, in the early 1980s a powerline and tower were constructed within the Hogback population of A. humillimu s destroying the northern part of this population (Service 1989). Similarly, the southern pa rt of this population was also extirpated during the same period from a rock qua rry operation (Service 1989). No new plants have ever been found in this area (Navajo Natural Heritage Program 2008a).

Impacts are generally associated with ma intaining transmission line roads and the associated vehicles that crush plants. Conservation measures recommended in the recovery plan (Service 1989) and the HM P for Navajo Nation lands (House and Engelking 1992), such as avoidance a nd transplanting, could minimize impacts within the construction foot print of these types of pr ojects. We do not know if these conservation measures were enacted on past projects, and whether they are being implemented currently. Thus, we believe that the ongoing impacts associated with transmission lines could be severe if they involve A. humillimus habitat, but could be easily mitigated by implementing recommended conservations measures along these proposed corridors.

Off-Highway Vehicles: Of f-highway vehicles (OHVs) were not a threat until recently, but their impacts are now being considered. The recreational use of OHVs has increased dramatically since the plant was listed. This increase is most likely due to the recent expansion of o il and gas extraction and the resultant population growth within San Juan County. From 1980 to 2006, the human population of San Juan county increased by 55 percent (http://wrdc.usu.edu/ht m/publications/). OHV-related damage to A. humillimus and its habitat has increased, especial ly around oil and gas well pads and transmission line corrid or roads (Service 1989; H ouse and Engelking 1992; Bureau of Land Management 2007; Nava jo Nation Natural Heritage Program 2007, 2008, and 2008b; Navajo Nation Depart ment of Fish and Wildlife 2009).

Unauthorized roads, trails, and recr eational OHV use on sandstone cliffs and outcrops have been observed on and near known populations of A. humillimus (Bureau of Land Management 2006). For example, surveys undertaken in 2006 on BLM plots found scattered glass and OHV tire marks where 24 plants were found alive and 11 dead; cause of morta lity was unknown, but this site is a popular recreational parking area with unrestricted access (Bureau of Land Management 2006). Not only did several plants appear damaged from being crushed, but their micro-habitat (small depr essions or tinajas) has been fractured leaving a dearth of requir ed habitat for future seedling establishment. Although19 most OHV activity is restricted to the s outhern part of the ACEC (outside of known milkvetch habita t), the potential for impacts still exists (K endall 2011). Lack of law enforcement continues to be problematic for both BLM and Navajo Nation. We believe that use of OHVs is presently a moderate threat to this species and will likely increase in the foreseeable future.

2.3.2.2 Overutilization for commercial, recrea tional, scientific, or educational purposes – Factor B:

Overutilization for commercial, recreationa l, scientific, or educational purposes has not been documented for A. humillimus . The species has no known commercial use and illegal collection does not appear to be a threat currently or in the foreseeable future.

2.3.2.3 Disease or predation – Factor C:

No diseases have been observed on this species. Herbivory by wildlife and livestock has not been repor ted although no formal studie s have been conducted. Livestock grazing is not considered a current threat, or a threat for the foreseeable future. Some insect herbivory by seed weevils and Lepidoptera larvae has been reported (NatureServe 2010), but appears to occur at insignificant levels during favorable rainfall years (New Mexico Stat e Forestry Division 2008). Spider mite infestations have been recorded and app ear to kill plants particularly during drought periods when the plant is alrea dy stressed (Siviniski and Knight 2001). The mites pierce the epidermis to ingest the sap which results in leaf discoloration and death, weakening the plant even furt her and causing mortality (Sivinski and Knight 2001). Insect infestations appear to be relatively rare, but could increase if drought continues into the foreseeable future. Thus, insect predation is considered a minor threat at this time.

2.3.2.4 Inadequacy of existing regul atory mechanisms – Factor D:

Astragalus humillimus was listed as threatened without critical habitat in June 1985 (50 FR 26568). The Act is the primar y Federal law providing protection for the species. Beyond the listing of the species, these protections are afforded particularly through sections 7 and 9 of th e Act. Section 7 of the Act requires Federal agencies to ensure that any ac tion authorized, funded, or implemented by them is not likely to jeopardize the conti nued existence of listed species or modify their critical habitat, if critical habita t has been designated. Section 7 also encourages Federal agencies to use their authorities to carry out programs for the conservation of listed species. Sectio n 9 of the Act prohibits the removal, damage, or destruction of listed plants on Federal lands and on other areas in knowing violation of any State law or regul ation or State criminal trespass law.

The National Environmental Policy Act (N EPA) may provide some protection for A. humillimus for projects with a Federal nexus (i.e., funding, authorization, or20 permitting). NEPA requires that the pl anning process for Federal actions be analyzed to ensure that effects on the environment are considered. The NEPA process is intended to help public offici als make better decisions based on an understanding of the environmental conse quences of their actions and to take actions to protect, restore, and enha nce the environment (40 CFR 1500.1). Carrying out the NEPA process ensures that agency decision makers have information about the environmental effect s of Federal actions and information on a range of alternatives that will accomplish the project purpose and need.

Federally listed plants occurring on priv ate lands have very limited protection under the Act unless they are also protected by State laws. Astragalus humillimus is listed as endangered by the Stat e of New Mexico under the New Mexico Endangered Plant Species Act, Sectio n 75-6-1 NMSA 1978, which protects it from unauthorized collection, transport, and sale, but provides no protection from land use impacts. There are no regulat ory protections for federally listed threatened and endangered plant specie s from surface disturbing land uses on private or state owned lands in New Me xico, unless they are authorized, funded, or carried out by a Federal agency and subjec t to section 7 consultation of the Act. Prohibitions for this species under State law would not be sufficient for its conservation if A. humillimus was delisted.

The Lacey Act, as amended in 1981, preven ts the import, export, sale, acquisition, purchase, or interstate or foreign comm erce of any plant and/or animal taken, possessed, or sold in violation of any la w, treaty, or regulat ion of the United States, any Indian tribal la w, or any regulation of any State. If transported or exchanged for currency, the plant coul d be protected under the Lacey Act.

Bureau of Land Management Manual 6840 establishes Special Status Species (SSS) policy for plant and animal species and the habitat on which they depend (Bureau of Land Management 2008). This SSS policy refers not only to species protected under the Act, but also to t hose designated by the BLM State Director as Sensitive. The BLM maintains A. humillimus as a SSS. The intent of the sensitive species designation is to ensu re actions on BLM administered lands consider the welfare of thes e species and do not contribute to the need to list any SSS under the provisions of the Act. As written, the BLM management prescriptions allow several avenues of protectio n for this plant including, but not limited to, managing existing oil and gas leases under Controlled Surface Use constraint and discretiona ry closure on new leases. These protective measures should be sufficient to the conservation of this species, yet negative impacts continue to occur particularly on Nava jo Nation lands with lease oversight by BLM. At this time, BLM’s SSS policy has not been sufficient for the conservation of this species.

The Hogback Area of Critical Environm ental Concern (ACEC), located on BLM administered lands, was established after A. humillimus was listed in 1987. This ACEC designation is intended to ensure that proposed projects in this area receive21 the highest environmental scrutiny before being implemented. Projects are not prevented from occurring in the ACEC, but recommendations may be made to modify them to protect certain critical resources including A. humillimus habitat. Despite these additional protections for listed species, recreational OHV use and energy maintenance activities continue to have the potential to impact known populations throughout the Hogback ACEC, thus this BLM designation has not been sufficient in the conservation of this species.

Navajo Tribal Code 17 Section 500(8) de fines and protects species in three Groups based on a species’ conservation stat us. Group 1 pertains to species or subspecies that are no longer found on th e Navajo Nation. Group 2 applies to species or subspecies whose prospects of survival or recruitment are in jeopardy, and Group 3 incorporates species or subsp ecies whose prospects of survival or recruitment are in jeopardy in the foreseeable future. Astragalus humillimus is listed as a Group 2 Endangered species on the Navajo Nation lands, which means that the species prospects of survival or recruitment are or are likely to be in jeopardy. Tribal laws protect species in Gr oup 2. Title 17 § 507 of the Navajo Tribal Code makes it unlawful for any pers on to “take, possess, transport, export, process, sell or offer for sale or ship any species or subspecies” on the Navajo Endangered Species List. Despite these regulatory mechanisms, continued habitat destruction through oil and gas develo pment has occurred, and none of the recovery actions identified in the 1985 recovery plan have been initiated on Navajo Nation lands (Navajo Nation De partment of Fish and Wildlife 2009).

Existing regulatory mechanisms, secured through the Act, have reduced some threats on Federal lands. In the absen ce of the Act’s protective regulatory mechanism, we believe the situation w ould be considerably worse. After considering the regulations other than the Act designed to protect this plant, and due to continued negative impacts to this species, we believe other Federal, Tribal, and State legal pr otections provided for this species have not been sufficient for its conservation in the foreseeable future.

2.3.2.5 Other natural or manmade factors affecting its cont inued existence – Factor E:

Pesticide Use: Pesticides are considered a potential threat because they could directly harm a plant, but also could indirectly kill pollinators of A. humillimus or their host plants (Service 1989). Herbicides are commonly used for noxious weed control, but no documentation ha s been provided on whether any A. humillimus populations have been directly or indire ctly affected. In the Navajo Nation Habitat Management Plan for A. humillimus from 1992, agricultural use of pesticides is mentioned in regard to the Navajo Indian Irrigation Project and local Navajo farmers along the San Juan River (House and Engelking 1992).

Pesticides, particularly insecticides, ar e linked to bee declines (Kearns et al. 1998, Kremen et al. 2002, National Academy of Sciences 2007), with the abundance22 and diversity of wild bee communities negatively correlated with increasingly intensive chemical applications of pe sticides (Tuell and Isaacs 2010). Although the toxicity of pesticides to pollinators is challenging to quantif y in a field setting and varies depending on the chemistry, qua ntity applied, degree of contact, area treated, and seasonal timi ng (Mineau et al. 2008, Tue ll and Isaacs 2010), some pesticides cause immediate mortality to bees if applied upon crops while bees are actively foraging (Johansen 1977). Both wild and honey bee ( Apis mellifera ) declines have been found in areas adjacen t to sprayed fields, suggesting a wider spatial impact to the pollinator community than just a target ed area (Kevan 1975, Kevan et al. 1990). Furthermore, depe nding on the seasonal timing of pesticide application, effects to pollinator commun ities may be chronic and cumulative, yet difficult to assess due to the different phenologies and nesting situations of pollinator species (Desneaux et al. 2007, Tuell and Isaacs 2010).

Pesticide application, partic ularly aerial spraying, occu rs in the local agricultural areas to control crop pests in Farm ington, New Mexico. Most of the A. humillimus populations are miles away, but coul d be affected by drift if aerial spraying were to occur on Navajo Nation lands, particularly the Navajo Indian Irrigation Project or local Navajo farm ers (House and Engelking 1992). There is no information on pesticide use and subsequent monitoring on Navajo lands and local farmers are not monitored. Due to th e lack of information, we are uncertain whether pesticides directly or in directly affect the survival of A. humillimus

. Thus, we do not consider pesticides to be a threat to this species currently or in the foreseeable future.

Natural Processes: Natural processes such as erosion could account for some mortality, yet they also are responsi ble for soil deposition in the bedrock depressions that are essentia l habitat for this species. Since this species is restricted to small and widely disperse d segments of sandstone, the resulting populations are disjunct and s cattered. This fragmented distribution impedes gene flow among subpopulations. Without the ma intenance of genetic diversity to buffer against stochastic events, the sp ecies becomes increasingly vulnerable to external threats. Genetic limitations (low fecundity) and ecological isolation (disjunct and small populations) increase th e risk of extinction when considering additional pressure from human impacts as well as stochastic events such as severe drought.

Climate Change: Based on the unequivocal evidence of warming of the earth’s climate from observations of increa ses in average global air and ocean temperatures, widespread melting of glaci ers and polar ice caps, and rising sea levels recorded in the Intergovernment al Panel on Climate Change Report (IPCC 2007), climate change is now a considerat ion for Federal agency analysis (GAO 2007). The earth’s surface has warmed by an average of 0.74 o C (1.3 o F) during the 20 th century (IPCC 2007) and, since 1960, the annual average temperature across the United States has increased by more than 2  F (1.1  C) (Global Climate Change Impacts in the United States [G CCIUS] 2009). The IPCC (2007) projects23 that there will very likely be an increase in the frequency of hot extremes, heat waves, and heavy precipitation events as a result of climat e change. The IPCC projects there will be an increase in the frequency of extreme weather events that are temporally and spatially more variab le as a result of cl imate change (IPCC 2007).

The most recent drought (2002-2003) spanning southwestern North America, prior to the current drought (winte r 2010-summer 2011), was anomalously dry with unusually high temperatures (Bresh ears et al. 2005). In Shiprock, NM, within A. humillimus habitat, no precipitation was recorded in 2002, whereas in 2004 only 33 mm (1.3 in) was recorded, the third lowest level measured since 1926 (Western Regional Climate Center 2010) . Mean annual precipitation since the drought (2003-2007) has been 97 mm (3.8 in), well below the long-term average (Western Regional Clim ate Center 2010; see Figure 3).

Climate change also involves an increas e in atmospheric carbon dioxide which is commonly associated with increased temp eratures and the greenhouse gas effect. Since 2000, the observed emissions of greenhouse gases, which are a key influence on climate change, have been o ccurring at the mid- to higher levels of the various emissions scenarios developed in the late 1990s and used by the IPPC for making projections (e.g., Raupach et al. 2007, Pielke et al. 2008, Manning et al. 2010). This increased carbon dioxide directly affects pl ant photosynthesis (Huxman and Scott 2007). At the plant level, adapting to drought involves the ability to balance carbon sequestration (the uptake and storage of carbon), carbon respiration (efflux back into the atmo sphere), and maintain sustainable evapotranspiration rates (Huxman and Sc ott 2007). Adaptation would also require a plant to change its phenology ( timing of life cycle events) to coincide successfully with extreme sh ifts in temperature, preci pitation, and soil moisture (Walther et al. 2002) which are all part of the evapotranspi ration equation. The potential for rapid climate change, which is predicted for the future, could pose significant challenges for plants because they may not be able to adjust their phenology or photosynthetic mechanisms quickly enough.

At the population level, A. humillimus is a spring flowering species (Service 1989). Growing seasons are becoming longer and warmer in many regions (Parmesan 2007) including the southwest (Cayan et al. 2001 ; Easterling 2002; Lenart et al. 2007; Enquist and Gory 2008). A reduction in soil moisture and earlier soil moisture stress to the plan t could decrease flowering and reproduction of the species. Because A. humillimus has a limited distribution, we would predict a substantial population reduction w ith a long-term warming trend.

Astragalus humillimus is likely to have experien ced and rebounded from periods of drought in the past. If climate change materializes with in creased severity and frequency of drought, it woul d likely reduce the long-term survivorship of this species. Narrow endemics, like A. humillimus , often have very specific habitat requirements. This species has affini ty for depressions in the sandstone,24 suggesting that water is critical for its germination and development, thus climate change could affect its continued existe nce. We believe the 2008 low population numbers are likely caused by cumulative losses since the 1980s due to several notable drought periods for this region, t hus we believe that climate change is a severe threat to this specie s in the foreseeable future.25 2.4 Synthesis

Prior to anthropogenic threats a nd anomalous climate extremes, A. humillimus populations likely adapted to more cyclic disturbance regime s with high mortality balanced by successful regeneration and reproduction. Preliminary obs ervations suggest that adult mortality is necessary for new seedling establishment, so th ere is a relatively shor t-term mortality cycle required for continued population establishment. However, cumulative mortality due to more frequent and extreme droughts from the 1980s to present may be affecting the baseline population size and the continued gene tic integrity of this species. Although some recovery is evident, population numbers have not returned to the earliest field estimations (approximately 10,000 on Navajo Nation lands as of 1989), and decreased dramatically after the 2002-2003 drought (less than 400 on Navajo Nation lands as of 2008). The overall p opulation trend appears to be declining in New Mexico; populati on size and status is unknown for Colorado.

Since the development of the recovery plan in 1989, threats have increased rangewide. Populations have been directly impacted by human caused disturbance which not only has killed plants, but also has destroyed the unique micro-ha bitat required for new seedling establishment. Although some level of regulatory protection exis ts for all known populations, these protective measures have not been applied sufficiently to ad equately protect the speci es. It appears that most of the negative impacts to this species occurred due to lack of on-the-ground enforcement of mitigation and conservation measures before , during, and after implementation of energy and transmission line projects.

Although the recovery criteria have not been entire ly met nor do we anticipate that they will be met in the foreseeable future, progress has been made by the ongoing census and mapping of known populations (Recovery Criterion 1); developm ent of a draft habitat management plan by Navajo Nation (Recovery Criterion 3); and installation of long-ter m monitoring plots that were last read in 2008 (Recovery Crit erion 4). As damage to plants may occur unintentionally, the construction of protective fencing around known popul ations to prevent in advertent destruction of plants could protect the remain ing individuals. Active, standa rdized surveying and monitoring to record the species’ status, and tracking of seed collection, germination, and survival would assist with the understanding a nd conservation of this plant. With the implementation and enforcement of conservation measures recommende d in the draft habitat management plan for Navajo Nation, and as specified for the Hogback ACEC on BLM land, recovery of this plant would be further supported.

Upon reviewing the combined sign ificance of current threats, we recommend that the federally endangered status of A. humillimus remain unchanged at this time. We also recommend that the plant be closely monitored for future population trends, new population discoveries, and the level of cumulative threats. We note that serious threats continue su ch as: (1) energy exploration, development, and maintenance activities; (2) tran smission line installation and maintenance; (3) increased off-road vehicle use; (4) inadequacy of implementing existing regulatory mechanisms; (5) increased understanding of this species’ genetic limitations within the context of ecological isolation and restricted distribut ion; and (6) predicted increase in frequency and severity of drought. For these reasons, this species continues to have a tenuous existence.26 3.0 RESULTS

3.1 Recommended Classification: No change; remain as endangered.

____ Downlist to Threatened ____ Uplist to Endangered

____ Delist

____ Extinction ____ Recovery ____ Original data for classification in error __X_ No change is needed

3.2 New Recovery Priority Number: 5C

Brief Rationale: We recommend the recovery priority number be changed from 2 (high degree of threat and high recovery poten tial) to a 5C (high degree of th reat and low recovery potential with some conflict). This change is justified ba sed on recent genetic research that indicates this species has low fecundity, which would increas e the potential for a genetic bottleneck in conjunction with its isolated and re stricted distribution, and limited micro-habitat. As well, there has been no long-term propagation success desp ite numerous attempts. Our review also indicates that human-caused threats such as energy development, transmission lines, and OHV use are more numerous at present than at the time of the listing and are more immediate. In combination, these factors indicate a low recovery pot ential is more appropriate for this plant at this time, and support the change from a high to a low r ecovery potential.

3.3 Listing and Reclassification Priority Number: Not applicable.27 4.0 RECOMMENDATIONS FOR FUTURE ACTIONS

 Revise recovery plan to incorporate new information on biology, ecology, threats, and conservation recommendations.

 Recommend Federal plant permittees report on number of seeds collected over time and status of attempts to germinate (success/failures). Because native seed bank viability and longevity in the field is unknown, knowing how many cumulative seeds are being taken from this rare species could be important to its future regenerative capacity in the field, particularly duri ng drought periods.

 Provide viable A. humillimus seeds to a seed bank operati ng under the Center for Plant Conservation guidelines.

 Continue research on species biology, eco logy, reclamation, and transplantation.

 Develop standardized survey and monitoring protocols for this species to be conducted annually by experienced personnel.

 Develop a mitigation banking requirement (a system whereby proponents of projects that may cause harm to A. humillimus or its habitat pay for plants to be preserved in an area suitable for their preservation as mitigation for losses incurred during projects).

 Develop an A. humillimus multi-agency working group to share and disseminate information regarding this listed spec ies by promoting education, protection, and recovery actions.

 Work with the BLM Farmington Field Offi ce to develop and implement consistent conservation measures in the Resource Mana gement Plan revision that will avoid and minimize impacts to A. humillimus and its habitat from livestock trampling, ORV activities, and energy development. Include protection for all occupied and suitable habitat in the cons ervation measures.

 Work with the Ute Mountain Ute tribe to en courage and support surv eys, monitoring and conservation measures for A. humillimus on their land, and development of their management plan to include this species.28 5.0 REFERENCES

Allphin, L, N. Brian and T. Matheson. 2005. Reproductive success an d genetic divergence among varieties of the rare and endangered Astragalus cremnophylax (Fabaceae) from Arizona, USA. Conservation Genetics 6:803-821.

Breshears, D., N. Cobb, P. Rich, K. Price, C. Allen, R. Balice, W. Romme, J. Kastens, M. Floyd, J. Belnap, J. Anderson, O. Myers, and C. Meyer. 2005. Regional vegetation die-off in response to global-change-type drought. Proceedings Natio nal Academy of Sciences 102(42):15144-48.

Bureau of Land Management. 2003. Farmington district resource management plan with record of decision. December 2003. Farm ington Field Office, Fa rmington, New Mexico.

Bureau of Land Management. 2006. Final repor t - BLM CPC oil shale seed collections, 2006. Submitted to BLM by the Arboretum at Flagstaff, Arizona.

Bureau of Land Management. 2007. Biological examination report of the Navajo B well #2 on the Navajo Nation. Lease #: 14-20-603- 583. API well #: 30-045-20622. Field and Pool: Horseshoe Gallup. BLM-Farmingt on Field Office, Farm ington, New Mexico.

Bureau of Land Management. 2008. Bureau of Land Management Manual – 6840 Special Status Species Management. Rel. 6-125, 12/12/2008.

Cayan, D., S. Kammerdiener, M. Dettinger, J. Caprio, and D. Peterson. 2001. Changes in the onset of spring in the western United Stat es. Bulletin of American Meteorological Society 82:399-415.

Center for Plant Conservation. 2010. Plant profile for Astragalus humillimus . Accessed 4/28/2010. Available at: http://centerforpl antconservation.org.

Colorado Natural Heritage Program. 2010. Element state rank report for Astragalus humillimus

. Retrieved 4/28/2010. Colorado State Univ ersity, Fort Collins, Colorado.

Desneaux, N., A. Decourtye, and J.M. Delpuech. 2007. The sublethal effects of pesticides on beneficial arthropods. Annual Review of Entomology 52:81-106.

Dick-Peddie, W. 1993. New Mexico Vegetati on. University of New Mexico Press, Albuquerque, New Mexico.

Ecosphere Environmental Services. 2006. Presence/absence summary report – Mesa Verde cactus ( Sclerocactus mesae-verde), Mancos milkvetch ( Astragalus humillimus ), and listed noxious weeds along segment A of the proposed Navajo Ttransmission Line. Prepared for Environmental Planning Group, Tucson, Arizona.29 Ecosphere Environmental Services. 2007. Draf t Lost Canyon-Shiprock and Kayenta-Shiprock Transmission Lines botanical resources surv ey on Navajo Nation lands in San Juan County, New Mexico. Prepared for We stern Area Power Administration, Rocky Mountain Customer Service Region.

Ecosphere Environmental Services. 2008a. Biologi cal assessment for the proposed Desert Rock Power Plant. Prepared for Bureau of Indian Affairs, Gallup, New Mexico.

Ecosphere Environmental Services. 2008b. Survey results for Mancos milkvetch for the Hart Oil and Gas natural gas well plug and abandonment project. Prepared for Steven Mason, Petroleum Engineer, Bureau of Land Manage ment, Farmington Field Office, Farmington, New Mexico.

Easterling, D. 2002. Recent changes in frost fr ee days and the frost-free season in the United States. Bulletin of American Meteorological So ciety 83:1327-1332.

Energy, Minerals and Natural Resources Depart ment. 2008. 2008 Annual report. New Mexico Energy, Minerals, and Natural Resources Department, Santa Fe, New Mexico.

Enquist, C. and D. Gori. 2008. A climate change vulnerability assessment for biodiversity in New Mexico, Part I: Implication of recent cl imate change on conservation priorities in New Mexico. The Nature Conservancy and Wildlife Conservation Society. http://nmconservation.org/dl/NMClimateChange_report1_527.pdf

Global Climate Change Impacts in the United St ates. 2009. T. R. Karl, J.R. Melillo, and T.C. Peterson (eds). Cambridge University Press, 189 pp.

Graham, L.E., J.M. Graham, and L.W. Wilcox. 2006. Plant Biology, 2 nd Edition. Pearson Prentice Hall, Upper Saddle River, New Jersey.

Haskins, K. and S. Murray. 2009. Ecological study and comparison of two rare Astragalus species – final report. The Arbor etum at Flagstaff, Arizona.

House, D. and L. Engelking. 1992. Habitat management plan for Astragalus humillimus (Mancos milkvetch). The Nature Conserva ncy, Western Regional Tr ibal Lands Program (San Juan Pueblo, NM) and Western Regiona l Heritage Task Force (Boulder, CO).

Huxman, T. and R. Scott. 2007. Climate cha nge, vegetation dynamics, a nd the landscape water balance. Southwest Hydrology, January/February 2007:28-29, 37.30 IPCC (In tergovernmental Panel on Climate Change). 2007. Summary for policymakers. In: Climate change 2007: the physical science ba sis. Contribution of working group one to the fourth assessment report of the intergove rnmental panel on climate change (Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor and H. L. Miller, eds.) Cambridge University Press, New York, New York. http://www.ipcc.ch/publications_and_data/pub lications_ipcc_fourth_assessment_report_ wg1_report_the_physical_science_basis.htm

Johansen, C.A. 1977. Pesticides and pollinat ors. Annual Review of Entomology 22:177-192.

Karron, J.D. 1989. Breeding systems and levels of inbreeding depression geographically restricted and widespread species of Astragalus (Fabaceae). American Journal of Botany 76:331-340.

Kearns, C.A., D.W. Inouye, and N.M. Waser. 1998. Endangered mutualisms: the conservation of plant-pollinator interactions. Annual Review of Ecology and Systematics 29:83-112.

Kendall, J. 2011. Email correspondence on the st atus of Mancos milkvetch and oil and gas development within the Hogback Area of Critical Environmental Concern (ACEC). Bureau of Land Management , Farmington, New Mexico.

Kevan, P.G. 1975. Forest application of the inse cticide fenitrothion and its effect on wild bee pollinators (Hymenoptera: Apoinde a) of lowbush blueberries ( Vaccinium spp.) in southern New Brunswick, Canada. Biological Conservation 7:301-309.

Kevan, P.G., E.A. Clark, and V.G. Thomas. 1990. Insect pollinators and sustainable agriculture. American Journal of Altern ative Agriculture 5:12-22.

Kremen, C., N.M. Willimans, and R.W. Thorp. 2002. Crop pollination from wild bees at risk from agricultural intensification. Proceedi ngs from the National Academy of Sciences 99:16812-16816.

Lenart, M., G. Garfin, B. Colby, T. Swetnam, B.J. Morehouse, S. Doster, and H. Hartmann. 2007. Global warming in the southwest: projections, observations, and impacts. Climate Assessment for the Southwest, University of Arizona. http://www.climas.arizona.edu/f iles/climas/GWSouthwest.pdf.

Manning, M.R., J. Edmonds, S. Emori, A. Grubler , K. Hibbard, F. Joos, M. Kainuma, R.F. Keeling, T. Kram, A.C. Manning, M. Meinshau sen, R. Moss, N. Nakicenovic, K. Riahi, S.K. Rose, S. Smith, R. Swart, & D.P. van Vuuren. 2010. Misrepresentation of the IPCC CO 2 emission scenarios. Nature Geoscience 3:376-377.

Mineau, P., K.M. Harding, M. Whiteside, M.R. Fletcher, D. Garthwaite , and L.D. Knopper. 2008. Using reports of bee mortality in the fi eld to calibrate laborat ory-derived pesticide risk indices. Environmental Entomology 37:546-554.31 National Academy of Sciences. 2007. Status of pollinators in North America. The National Academies Press, Washington, D.C.

NatureServe. 2010. NatureServe Explorer: An online ency clopedia of life [web application]. Version 7.0. NatureServe. Arlington, VA. Available at: http://www.natureserve.org/explorer/.

Navajo Nation Department of Fish and Wildlife. 2009. Letter summarizi ng status regarding the 5-year review of Mancos Milkvetch ( Astragalus humillimus ). May 13, 2009. Navajo Nation, Window Rock, Arizona.

Navajo Natural Heritage Program. 2007. Memorandum: Disturbance of Astragalus humillimus EOR #6 by plugging and abandonment operatio ns on Palmer Mesa. May 14, 2007.

Navajo Natural Heritage Program . 2008a. Mancos milkvetch ( Astragalus humillimus ) Trend/Status Assessment. Daniela Roth, au thor. Navajo Natural Heritage Program, Window Rock, Arizona.

Navajo Natural Heritage Program. 2008b. Fi eld report regarding damage and ground work conducted on Palmer Mesa by Hart Oil and Ga s Inc., Lease no. 14-20- 603-584 at site of known Mancos milkvetch ( Astragalus humillimus ) populations. April 8, 2008.

New Mexico State Forestry Division (State of New Mexico). 2008. Population studies of Mancos milkvetch ( Astragalus humillimus : Fabaceae) in San Juan County, New Mexico from 1988 to 2008. R. Sivinski, author. Ne w Mexico Energy, Minerals, and Natural Resources Department, Santa Fe, New Mexico.

Parmesan, C. and H. Galbraith. 2004. Observed impacts of global climate change in the U.S. Pew Center on Global Climate Change, Arlingt on, VA. Prepared for the Pew Center on Global Climate Change, November 2004.

Parmesan, C. 2007. Influences of species, latitudes and methodologies on estimates of phenological response to global warmi ng. Global Change Biology 13:1860-1872.

Pielke Jr., R., T. Wigley, and C. Green. 2008. Dangerous assumptions. Nature 452:531-532.

Raupach, M.R., G. Marland, P. Ciais, C. Le Quéré, J.G. Canadell, G. Klepper, and C.B. Field. 2007. Global and regional drivers of accelerating CO 2 emissions. Proceedings of the National Academy of Sciences. cgi/doi/10.1073/pnas.0700609104

Sivinski, R.C. and P.C. Knight. 2001. Popul ation characteristics of Mancos milkvetch ( Astragalus humillimus : Fabaceae) in San Juan County, New Mexico. New Mexico Naturalist Notes 3(1):51-61.32 Tepedino, V.J. 2002. The reproductive biology of ra re rangeland plants a nd their vulnerability to insecticides. In: Cunningham, G.L., Sa mpson, M.W., tech. cords. 1996. Grasshopper integrated pest management user handbook. Tech. Bull. 1809. Washington, DC: US Department of Agriculture, Animal and Plant Health Inspection Service. Available at: http://www.sidney.ars.usda.gov/gr asshopper/Handbook/III/iii_5.htm.

Tuell, J.K. and R. Isaacs. 2010. Community and species-specific responses of wild bees to insect pest control programs applied to a pol linator-dependent crop. Journal of Economic Entomology 103(3):668-675.

Udall, B. and G. Bates. 2007. Climatic and hydro logic trends in the West ern U.S.: A review of recent peer-reviewed resear ch. Intermountain West C limate Summary 3(1): 2-8.

U.S. Fish and Wildlife Service. 1985. Enda ngered and threatened wildlife and plants; final rule to determine Astragalus humillimus to be endangered. Federal Register. 50 (124):26568-26572.

U.S. Fish and Wildlife Service. 1989. Mancos milkvetch ( Astragalus humillimus ) recovery plan. P. Knight and D. House, authors. New Mexico Ecological Services Field Office, Albuquerque, New Mexico.

U.S. Fish and Wildlife Service. 2010. Project Title: Ecolog ical study and comparison of two

rare Astragalus species. Permit # TE009792-2 an d TE226653-0. The Arboretum at Flagstaff, Arizona.

Walther, G., E. Post, P. Convey, A. Menzel, C. Parmesan, T. Beebee, J. Fromentin, O. HoeghGuldberg, and F. Bairlein. 2002. Ecological re sponses to recent climate change. Nature 416:389-395.

Western Regional Climate Center. 2010. Historical climate info rmation, Western U.S. climate historical summaries. New Mexico; Sh iprock; Monthly Total Precipitation. http://www.wrcc.dri.edu.