Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Amoreuxia gonzalezii, Astragalus hypoxylus, and Erigeron piscaticus as Endangered or Threatened, 62722-62740 [2011-25470]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 196 (Tuesday, October 11, 2011)]
[Proposed Rules]
[Pages 62722-62740]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-25470]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2011-0081; MO92210-0-0008]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List Amoreuxia gonzalezii, Astragalus hypoxylus, and 
Erigeron piscaticus as Endangered or Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list Amoreuxia gonzalezii (Santa Rita 
yellowshow), Astragalus hypoxylus (Huachuca milk-vetch), and Erigeron 
piscaticus (Fish Creek fleabane) as endangered or threatened with 
critical habitat under the Endangered Species Act of 1973, as amended 
(Act). After review of the best scientific and commercial information 
available, we find that listing Amoreuxia gonzalezii, Astragalus 
hypoxylus, and Erigeron piscaticus is not warranted at this time. 
However, we ask the public to submit to us any new information that 
becomes available concerning the threats to Amoreuxia gonzalezii, 
Astragalus hypoxylus, and Erigeron piscaticus or their habitats at any 
time.

DATES: The finding announced in this document was made on October 11, 
2011.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R2-ES-2011-0081. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours by contacting 
the U.S. Fish and Wildlife Service, Arizona Ecological Services Field 
Office, 2321 W. Royal Palm Road, Suite 103, Phoenix, AZ 85021; 
telephone (602) 242-0210; facsimile (602) 242-2513. If you use a 
telecommunications device for the deaf (TDD), please call the Federal 
Information Relay Service (FIRS) at (800) 877-8339. Please submit any 
new information, comments, or questions concerning this finding to the 
above street address.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, U.S. 
Fish and Wildlife Service, Arizona Ecological Services Field Office, 
2321 W. Royal Palm Road, Suite 103, Phoenix, AZ 85021; telephone (602) 
242-0210; facsimile (602) 242-2513. If you use a telecommunications 
device for the deaf (TDD), please call the Federal Information Relay 
Service (FIRS) at (800) 877-8339.

SUPPLEMENTARY INFORMATION: 

Background

    Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires 
that, for any petition to revise the Federal Lists of Threatened and 
Endangered Wildlife and Plants that contain substantial scientific or 
commercial information indicating that listing a species may be 
warranted, we make a finding within 12 months of the date of receipt of 
the petition. In this finding, we will determine that the petitioned 
action is: (a) Not warranted, (b) warranted, or (c) warranted, but 
immediate proposal of a regulation implementing the petitioned action 
is precluded by other pending proposals to determine whether species 
are endangered or threatened, and expeditious progress is being made to 
add or remove qualified species from the Lists of Endangered and 
Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires 
that we treat a petition for which the requested action is found to be 
warranted but precluded as though resubmitted on the date of such 
finding, that is, requiring a subsequent finding to be made within 12 
months. We must publish these 12-month findings in the Federal 
Register.

Previous Federal Actions

    Amoreuxia gonzalezii, Astragalus hypoxylus, and Erigeron piscaticus 
were formerly Category 2 candidate species, which are taxa for which 
information in our possession indicated that proposing to list was 
possibly appropriate, but for which persuasive data on biological

[[Page 62723]]

vulnerability and threats were not available to support a proposed 
listing rule (58 FR 51144; September 30, 1993). The designation of 
Category 2 candidate species was discontinued in 1996; therefore, these 
species are not currently considered candidates.
    On June 25, 2007, we received a formal petition dated June 18, 
2007, from Forest Guardians (now WildEarth Guardians), requesting that 
we do the following: (1) Consider for listing all full species in our 
Southwest Region ranked as G1 or G1G2 by the organization NatureServe, 
except those that are currently listed, proposed for listing, or 
candidates; and (2) list each species under the Act as either 
endangered or threatened and designate critical habitat. The 
petitioners presented two tables that collectively listed 475 species 
for consideration and requested that the Service incorporate all 
analyses, references, and documentation provided by NatureServe in its 
online database https://www.natureserve.org/ into the petition. The 
petition clearly identified itself as a petition and included the 
appropriate identification information, as required in 50 CFR 
424.14(a). We acknowledged the receipt of the petition in a letter to 
WildEarth Guardians dated July 11, 2007.
    On December 16, 2009, we made a 90-day finding (74 FR 66866) that 
the petition presented substantial scientific information indicating 
that listing 67 of the 475 species may be warranted; Amoreuxia 
gonzalezii, Astragalus hypoxylus, and Erigeron piscaticus were in that 
group of 67 species. For Amoreuxia gonzalezii, the petition listed 
urban and mining development and herbivory as threats to the species 
and its habitat, along with competition from nonnative species. For 
Astragalus hypoxylus, the petition listed degradation of habitat from 
livestock grazing and impacts from recreation, as well as indirect 
effects to bees, which may be the primary pollinator of this species. 
For Erigeron piscaticus, the petition listed recreational impacts, poor 
watershed conditions, flooding, and small population size as threats to 
the species and its habitat. The 90-day finding initiated a status 
review for these three plants (74 FR 66866; December 16, 2009). This 
notice constitutes the 12-month finding on the June 18, 2007, petition 
to list Amoreuxia gonzalezii, Astragalus hypoxylus, and Erigeron 
piscaticus as endangered or threatened.

Evaluation of the Status of Each of the Three Plant Species

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR part 424) set forth procedures for adding species to, removing 
species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be endangered or threatened 
based on any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making these findings, information pertaining to each species in 
relation to the five factors provided in section 4(a)(1) of the Act is 
discussed below. In considering what factors might constitute threats 
to a species, we must look beyond the exposure of the species to a 
particular factor to evaluate whether the species may respond to the 
factor in a way that causes actual impacts to the species. If there is 
exposure to a factor and the species responds negatively, the factor 
may be a threat, and during the status review, we attempt to determine 
how significant a threat it is. The threat is significant if it drives, 
or contributes to, the risk of extinction of the species such that the 
species warrants listing as endangered or threatened as those terms are 
defined by the Act. However, the identification of factors that could 
impact a species negatively may not be sufficient to compel a finding 
that the species warrants listing. The information must include 
evidence sufficient to suggest that the potential threat has the 
capacity (i.e., it should be of sufficient magnitude and extent) to 
affect the species' status such that it meets the definition of 
endangered or threatened under the Act.

Evaluation of the Status of Each of the Three Plant Species

    For each of the three species, we provide a description of the 
species and its life-history and habitat, an evaluation of threats for 
that species, and our finding that the petitioned action is warranted 
or not for that species.

Species Information for Amoreuxia gonzalezii

 Species Description

    Amoreuxia gonzalezii is an herbaceous perennial (plant living 3 or 
more years) in the Bixaceae family (Lipstick tree). The plant has a 
thickened starchy to woody rootstock, erect stems to 50 centimeters 
(cm) (20 inches (in)) in height, and long-petioled (long-stalked) 
leaves that are deeply parted into five to seven spathulate (spoon-
shaped) lobes (Poppendieck 1981, p. 24). The inflorescences (clusters 
of flowers) are few-flowered terminal cymes (branched flower clusters) 
with salmon- to yellow-colored flowers with maroon marks at the base of 
the upper and lower petals (Hodgson 1994, p. 3). The densely silky hair 
of the ovary is one of two main characteristics that separate this 
species from its more common relative A. palmatifida (Hodgson 1994, p. 
4). The second characteristic separating the two species is the mature 
fruit. The capsule in A. gonzalezii is ellipsoid and the seeds 
spherical; in A. palmatifida, the capsules are ovoid with reniform 
(kidney-shaped) seeds (Hodgson 1993, p. 27). Recent molecular work by 
Fulton (2011, pers. comm.) verifies that A. gonzalezii is a valid 
taxon, and we consider the species a listable entity.

Habitat and Biology

    Amoreuxia gonzalezii is the farthest north-occurring species within 
this tropical and sub-tropical genus found primarily in South America 
(the primary center of diversification), Central America, and Mexico 
(Poppendieck 1981, p. 24). Northern Mexico is the secondary center of 
diversification for the genus and contains the majority of documented 
locations of A. gonzalezii (Hodgson 1994, p. 5). In Mexico, A. 
gonzalezii is found in tropical areas in foothills thornscrub and 
tropical deciduous forest. Rainfall amounts range from 28 cm per year 
(11 in) near the coast (thornscrub) to 60 cm (24 in) in tropical 
deciduous forest. Freezes are very uncommon, and the bulk of rainfall 
occurs from July through mid-September. The plants in these vegetation 
communities are rainfall sensitive; in other words, the shrubs and 
trees leaf out only when the rains begin, and drop their leaves when 
the rainy season ends, usually in October (Yetman and Van Devender 
2002, pp. 9-12). Geology of collection sites varies from granitic, to 
quartz, to shale with quartz nodules and intrusives (molten igneous 
rock that is forced into cracks or between other layers of rocks). In 
the state of Sonora in Mexico, A. gonzalezii has been collected from 
the vicinity of [Aacute]lamos, Choquincahui, El Oasis, Guirocoba, 
Magdalena, Moctezuma, Onavas, Santa Ana, T[oacute]nichi, and Yocogigua, 
as well as the Curea-Guadalupe Tayopa area. In the state of Sinaloa in 
Mexico, the plant was

[[Page 62724]]

described from near Choix in the north. The specimens were found on 
both shallow and steep hill slopes at elevations from 160 to775 meters 
(m) (525 to 2542 feet (ft)).
    In the United States, Amoreuxia gonzalezii has been collected from 
the Devil's Cashbox area in the Santa Rita Mountains and Thomas Canyon 
in the Baboquivari Mountains (Southwest Environmental Information 
Network 2011). Both locations are in southeastern Arizona. We believe 
that the Arizona locations represent the northernmost distribution of 
this species. The Santa Rita A. gonzalezii plants are on lands 
administered by the Coronado National Forest, Nogales Ranger District. 
The plants occur in the foothills at an elevation of 1,311 to 1,402 m 
(4,300 to 4,599 ft) on steep limestone slopes and ridgetops. The 
habitat is described as the transition zone between Upper Sonoran 
desertscrub and grassland (NatureServe 2010). The collection from the 
granitic Baboquivari Mountains was from the sandy bank of a small 
drainage on private land at 1,280 to 1,371 m (4,198 to 4,497 ft) 
elevation. This site was described as an oak woodland and grassland 
(Southwest Environmental Information Network 2011).
    Very little is known about the biology of this species. Amoreuxia 
gonzalezii has a drought avoidance adaptation and only produces stems, 
leaves, flowers, and fruits following monsoon rains; it remains dormant 
under the ground the remainder of the year (Coronado National Forest 
1991, p. 3). Flowering occurs from July through September; flowers 
remain open only in the morning hours, closing by 11:00 a.m. (Hodgson 
1994, p.7). The species is an obligate outcrosser (needs pollen from 
another individual to successfully produce seed) and may be pollinated 
by unknown species of bees (Hodgson 1994, p. 7). Fruits develop in late 
July and August, maturing in September to mid-October (Hodgson 1994, p. 
7). Both flower and fruit production is dependent on the quantity of 
summer precipitation. Amoreuxia gonzalezii also reproduces vegetatively 
(asexually) from thick, tuberous or woody roots (Hodgson 2001, p. 94).
    In 1987 and 1988, staff from the Desert Botanical Garden (Garden) 
collected 142 seeds from the Devil's Cashbox area as part of the Center 
for Plant Conservation National Collection program for conserving rare 
plants and their seeds. The Garden's purpose was to determine viability 
of stored seed and increase the number of plants in their living 
collection (Desert Botanical Garden 1991, p. 1). An additional 72 seeds 
were collected by Garden staff from one population in Sonora, Mexico at 
an unknown date prior to 1991. In greenhouse trials, the Garden had 
variable low rates of success, from 0 to 43 percent, in germinating 4-
year-old seed stored both at room temperature and in a freezer 
facility. Viability of the seed bank and germination success in the 
wild is unknown, though Hodgson did report finding 10 seedlings in 1991 
in the Devil's Cashbox area (Southwest Environmental Information 
Network 2011). In a greenhouse experiment, 4 plants produced 7 fruits 
with a total of 232 seeds (Hodgson 1994, p. 7). Assuming this may be 
optimum fruiting potential given ample water and greenhouse care, the 
small population sizes from known populations (4to 24 individuals) may 
produce few seeds in typical years. There are no monitoring plots or 
current research in any of the populations in Arizona and Mexico.

Abundance

    There are virtually no population estimates for any locations in 
Mexico, although Hodgson (1994, p. 7) reported that one population in 
Mexico in 1988 had ``well over two dozen'' individuals. The information 
is not much better for the Arizona populations. Population estimates 
for the Santa Rita population ranged from 14 individuals in 1988 
(Southwest Environmental Information Network, 2011), to 4 individuals 
in 1989 (Hodgson 1989, p. 2), and 25 individuals in 1991 (Southwest 
Environmental Information Network, 2011). Hodgson (1994, p. 7) reports 
fewer than 24 individuals from 2 micro-populations in the Santa Rita 
Mountains. There were an estimated six to eight individuals in the 
Thomas Canyon population (Toolin 2011, pers. comm.) in the 1990s. 
Thomas Canyon was surveyed in 2011 and 30 plants were found (M. Baker 
2011, pers. comm.).
    In summary, there is very little ecological information available 
regarding Amoreuxia gonzalezii. The species is found in Mexico, and the 
United States, where the Arizona locations seem to represent the 
northernmost locations for this species. The best available scientific 
information does not indicate that this species was more widespread or 
that known populations have been extirpated. Both populations in 
Arizona seem to support a few individuals that are widely scattered 
over appropriate habitat. The species' growth is tied to the summer 
rains (monsoon), and in the fall, the plants become dormant. It seems 
likely that this species is more abundant in Mexico, and may be more 
closely tied with the thornscrub and tropical deciduous forest plant 
communities, which are more humid, and where many plant species grow in 
response to summer rainfall.

Five-Factor Evaluation for Amoreuxia gonzalezii

    In making this finding, information pertaining to Amoreuxia 
gonzalezii in relation to the five factors provided in section 4(a)(1) 
of the Act is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

    Potential factors that may affect the habitat or range of Amoreuxia 
gonzalezii are discussed in this section, including: (1) Nonnative, 
invasive species; (2) fire; (3) development; (4) mining; (5) watershed 
degradation; (6) drought; and (7) climate change.
Nonnative, Invasive Species
    Throughout the Sonoran Desert ecosystem, invasions of the 
introduced Pennisetum ciliare (buffelgrass), Bromus rubens (red brome), 
Eragrostis lehmanniana (Lehmann lovegrass), Schismus barbatus 
(Mediterranean grass), and Pennisetum setaceum (crimson fountaingrass) 
have altered nutrient regimes; species composition and structure; and 
fire frequency, duration, intensity, and magnitude (Brooks and Pyke 
2001, p. 5). Although most of these species were intentionally 
introduced as forage for livestock, erosion control, or as ornamentals, 
each is now considered invasive and a threat to this ecosystem. Species 
such as P. ciliare are expected to increase their range even with 
continued and predicted drought events (Ward et al. 2006, p. 724). It 
is generally thought that invasion by exotic annual grasses will 
continue unchecked in the Sonoran Desert ecosystem in the future, 
reducing native biodiversity through direct competition and alteration 
of nutrient and disturbance regimes (Franklin and Molina-Freaner 2010, 
p. 1671).
    Although exotic grasses are reported to threaten Amoreuxia 
gonzalezii (Hodgson 1989, p. 3), no exotic grasses were noted within 
the Devil's Cashbox habitat during field surveys in May 2011 (Service 
2011a, p. 1). We have reviewed the best available scientific 
information on exotic plants in or near populations of A. gonzalezii in 
Thomas Canyon and in Mexico. In order to verify the identification and 
location of plants, specimens are collected, pressed and placed on 
sheets that are stored in herbaria. The labels on herbarium sheets 
often note associated plant species that

[[Page 62725]]

are found in association with the collected specimen. There are no 
exotic species noted as associates on any of the 12 specimen herbarium 
sheets located at the Arizona State University, University of Arizona, 
or the Sonoran University Herbarium collections, nor were any exotics 
noted in the Devil's Cashbox and Sonora A. gonzalezii habitat 
descriptions in Hodgson 1994 (pp. 5-6). Therefore, the best available 
information does not provide evidence that nonnative invasive species 
are a threat to the continued existence of A. gonzalezii or are likely 
to become so.
Fire
    There has been no scientific study on the impacts of fire on 
Amoreuxia gonzalezii. This species is present aboveground in July 
through October, and is dormant the remainder of the year. Because 
fires in Arizona usually burn in the premonsoon season (May-June), it 
seems unlikely that fire would affect this species (Alford et al. 2005, 
p. 453). In addition, the plant has a large starchy root, which is 
protected underground. It is possible that the root would be protected 
from surface fire, allowing the plant to resprout after fire. In 
summary, given the limited available information about the effect of 
fire on A. gonzalezii, we have determined that fire is not a threat to 
the continued existence of A. gonzalezii, or is likely to become so.
Development
    The Santa Rita Amoreuxia gonzalezii population is located below the 
Smithsonian Fred Whipple Observatory, located on Mt. Hopkins. There is 
a visitor center for the observatory located at the base of Mt. 
Hopkins, and Hodgson (1989, p. 4) noted that during the construction of 
the visitor center, disturbance came very close to some A. gonzalezii 
plants on the Devil's Cashbox ridge, but none of the plants were harmed 
during construction. Hodgson (1994, p. 9) noted that communication is 
vital among researchers, land managers, and potential developers in 
regards to development near populations of A. gonzalezii. Available 
information does not indicate any other development planned for this 
area, and the area is fairly remote. In addition, the population is on 
National Forest land, where development is not likely to occur. There 
is also no information indicating any development near the Thomas 
canyon site, nor any development near Amoreuxia populations in Mexico. 
We have evaluated and determined, on the basis of the best available 
scientific and commercial data, that development is not a threat to the 
continued existence of A. gonzalezii, nor is it likely to become so.
Mining
    NatureServe (2010) reports mining as a threat to this species, 
perhaps due to the proximity of two active mining claims to the south 
of the Devil's Cashbox plants (Ahern 2011, pers. comm.). There are 
currently no known direct impacts of active or proposed mines on any 
known population of Amoreuxia gonzalezii in the United States; these 
impacts are unknown for populations in Mexico. Hodgson (2001, p. 93) 
notes that A. gonzalezii tubers were collected frequently by native 
peoples from ``a graphite mine site'' in Mexico, implying no negative 
impact on the plant from this particular mine. It is unknown if the 
mine was active or inactive at the times of harvesting. In summary, 
based upon our review of the best available information, we conclude 
that mining is not a threat to the continued existence of A. 
gonzalezii, nor is it likely to become so.
Watershed Degradation
    Improper livestock grazing can lead to habitat degradation and 
watershed degradation. Overgrazing removes the vegetative cover which 
can lead to erosion. The Santa Rita population is located within the 
Agua Caliente grazing allotment on the Nogales Ranger District. 
Degradation of habitat due to livestock grazing was noted as a threat 
by NatureServe (2010) to Amoreuxia gonzalezii, although this was not 
evident in a 2011 visit to the Devil's Cashbox area (Service 2011a, p. 
1). The area that was assessed during that visit had no signs of 
livestock trailing, or sign of livestock. The Forest Service reports 
that this allotment, comprised of one pasture, is permitted for a 110 
cow-calf operation (Lockwood 2011, pers. comm.). The grazing season is 
May to November, but only 40 cows are presently grazing due to drought 
conditions (Lockwood 2011, pers. comm.). The ridges where the plants 
are located are quite steep, and it is unlikely that cattle graze in 
these locations. The status of livestock grazing with regard to the 
Thomas Canyon population is unknown, and no information is available 
regarding livestock grazing near Amoreuxia populations in Mexico. After 
reviewing the best available scientific information, we have determined 
that watershed degradation as a result of livestock grazing is not a 
threat to the continued existence of this species, nor is it likely to 
become so.
Drought
    Amoreuxia gonzalezii is dependent upon monsoon rains both for 
growth and the production of flowers and fruits (Hodgson 1989, p. 3). 
Hodgson (2001, p. 94) states that, ``With little precipitation, few 
fruits are produced from very depauperate plants.'' The Thomas Canyon 
location experienced less than average monsoon precipitation in 27 of 
49 recorded years (July to August, period of record for average was 
1961-2010, Kit Peak Weather Station, WRCC 2011). Similarly, the Devil's 
Cashbox area has had less than average monsoon precipitation during 33 
of 63 recorded years (period of record for average was 1946-2010, 
Tumacacori National Historic Park (NHP) Weather Station, WRCC 2011). In 
both locations, monsoon patterns varied yearly, with periods of below-
average precipitation never exceeding 7 consecutive years (Tumacacori 
NHP 1998-2004), thus giving A. gonzalezii periods of recovery.
    The climate pattern in the vicinity of [Aacute]lamos at the 
southern end of the Amoreuxia gonzalezii range in Sonora is very 
similar to Arizona, with the [Aacute]lamos-El Veranito weather station 
reporting below-average monsoon precipitation in 14 of 28 recorded 
years (July to August, period of record for average was 1977-2009, 
Comisi[oacute]n Nacional del Agua (CNA), 2011). At the near center of 
A. gonzalezii's Sonora range, the Carbo Weather station reported below 
average monsoon precipitation in 30 of 50 recorded years, 10 of which 
were consecutive from 1960-1969 (July to August, period of record for 
average was 1960-2009, CNA, 2011).
    It is not known whether Amoreuxia gonzalezii is drought-tolerant, 
but the observation that plants are still present in sites that have 
experienced reduced summer precipitation leads us to conclude that the 
species is at least adapted to drought conditions. A. gonzalezii has 
fleshy underground tubers, which can store food and water, and that is 
an adaptation for dealing with drought. The best available information 
does not indicate that drought is a threat to the continued existence 
of A. gonzalezii, and the plant may have some adaptations for dealing 
with drought; therefore, we conclude that drought is not a threat to 
this species, or is likely to become so.
Climate Change
    ``Climate'' refers to an area's long-term average weather 
statistics (typically for at least 20- or 30-year periods), including 
the mean and variation of surface variables such as temperature,

[[Page 62726]]

precipitation, and wind; ``climate change'' refers to a change in the 
mean or variability of climate properties that persists for an extended 
period (typically decades or longer), whether due to natural processes 
or human activity (Intergovernmental Panel on Climate Change (IPCC) 
2007a, p. 78). Although changes in climate occur continuously over 
geological time, changes are now occurring at an accelerated rate. For 
example, at continental, regional and ocean basin scales, recent 
observed changes in long-term trends include: a substantial increase in 
precipitation in eastern parts of North American and South America, 
northern Europe, and northern and central Asia, and an increase in 
intense tropical cyclone activity in the North Atlantic since about 
1970 (IPCC 2007a, p. 30); and an increase in annual average temperature 
of more than 2 [deg]F (1.1[deg]C) across the U.S. since 1960 (Global 
Climate Change Impacts in the United States (GCCIUS) 2009, p. 27). 
Examples of observed changes in the physical environment include: an 
increase in global average sea level, and declines in mountain glaciers 
and average snow cover in both the northern and southern hemispheres 
(IPCC 2007a, p. 30); substantial and accelerating reductions in Arctic 
sea-ice (e.g., Comiso et al. 2008, p. 1), and a variety of changes in 
ecosystem processes, the distribution of species, and the timing of 
seasonal events (e.g., GCCIUS 2009, pp. 79-88).
    The IPCC used Atmosphere-Ocean General Circulation Models and 
various greenhouse gas emissions scenarios to make projections of 
climate change globally and for broad regions through the 21st century 
(Meehl et al. 2007, p. 753; Randall et al. 2007, pp. 596-599), and 
reported these projections using a framework for characterizing 
certainty (Solomon et al. 2007, pp. 22-23). Examples include: (1) It is 
virtually certain there will be warmer and more frequent hot days and 
nights over most of the earth's land areas; (2) it is very likely there 
will be increased frequency of warm spells and heat waves over most 
land areas, and the frequency of heavy precipitation events will 
increase over most areas; and (3) it is likely that increases will 
occur in the incidence of extreme high sea level (excludes tsunamis), 
intense tropical cyclone activity, and the area affected by droughts 
(IPCC 2007b, p. 8, Table SPM.2). More recent analyses using a different 
global model and comparing other emissions scenarios resulted in 
similar projections of global temperature change across the different 
approaches (Prinn et al. 2011, pp. 527, 529).
    All models (not just those involving climate change) have some 
uncertainty associated with projections due to assumptions used, data 
available, and features of the models; with regard to climate change 
this includes factors such as assumptions related to emissions 
scenarios, internal climate variability and differences among models. 
Despite this, however, under all global models and emissions scenarios, 
the overall projected trajectory of surface air temperature is one of 
increased warming compared to current conditions (Meehl et al. 2007, p. 
762; Prinn et al. 2011, p. 527). Climate models, emissions scenarios, 
and associated assumptions, data, and analytical techniques will 
continue to be refined, as will interpretations of projections, as more 
information becomes available. For instance, some changes in conditions 
are occurring more rapidly than initially projected, such as melting of 
Arctic sea ice (Comiso et al. 2008, p. 1; Polyak et al. 2010, p. 1797), 
and since 2000, the observed emissions of greenhouse gases, which are a 
key influence on climate change, have been occurring at the mid- to 
higher levels of the various emissions scenarios developed in the late 
1990s and used by the IPCC for making projections (e.g., Raupach et al. 
2007, Figure 1, p. 10289; Manning et al. 2010, Figure 1, p. 377; Pielke 
et al. 2008, entire). Also, the best scientific and commercial data 
available indicates that average global surface air temperature is 
increasing and several climate-related changes are occurring and will 
continue for many decades even if emissions are stabilized soon (e.g. 
Meehl et al. 2007, pp. 822-829; Church et al. 2010, pp. 411-412; 
Gillett et al. 2011, entire).
    Changes in climate can have a variety of direct and indirect 
impacts on species, and can exacerbate the effects of other threats. 
Rather than assessing ``climate change'' as a single threat in and of 
itself, we examine the potential consequences to species and their 
habitats that arise from changes in environmental conditions associated 
with various aspects of climate change. For example, climate-related 
changes to habitats, predator-prey relationships, disease and disease 
vectors, or conditions that exceed the physiological tolerances of a 
species, occurring individually or in combination, may affect the 
status of a species. Vulnerability to climate change impacts is a 
function of sensitivity to those changes, exposure to those changes, 
and adaptive capacity (IPCC 2007, p. 89; Glick et al 2011, pp. 19-22). 
As described above, in evaluating the status of a species, the Service 
uses the best scientific and commercial data available, and this 
includes consideration of direct and indirect effects of climate 
change. As is the case with all potential threats, if a species is 
currently affected or is expected to be affected by one or more 
climate-related impacts, this does not necessarily mean the species is 
an endangered or threatened species as defined under the Act. If a 
species is listed as endangered or threatened, this knowledge regarding 
its vulnerability to, and impacts from, climate-associated changes in 
environmental conditions can be used to help devise appropriate 
strategies for its recovery.
    While projections from global climate model simulations are 
informative and in some cases are the only or the best scientific 
information available, various downscaling methods are being used to 
provide higher-resolution projections that are more relevant to the 
spatial scales used to assess impacts to a given species (see Glick et 
al, 2011, pp. 58-61).
    Regional landscapes can be examined by analyzing climate models 
that operate at small spatial scales; however, this approach involves 
some uncertainty. The uncertainty arises due to various factors related 
to difficulty in applying climate modeling to a smaller scale or 
unknown information, including regional weather patterns, local 
physiographic conditions, and fine-scale weather factors. Also, climate 
models do not model biological responses, such as life stages of 
individual species, generation time of species, and species' reactions 
to changing carbon dioxide levels not being included in the models. 
Most climate models do not incorporate a variety of plant-related 
factors that could be informative in determining how climate change 
could affect plant species (e.g., effect of elevated carbon dioxide on 
plant water-use efficiency, the physiological effects on species of 
exceeding the assumed (modeled) bioclimatic limit, the life stage at 
which the limit affects the species (seedling versus adult), the 
lifespan of the species, and the movement of other organisms into the 
species' range) (Shafer et al. 2001, p. 207).
    For southern Arizona, the most current downscaled climate 
projections are available with \1/8\ degree resolution (approximately 
12 km x 12 km) from the Coupled Model Intercomparision Project (Maurer 
et al. 2007, entire). A West-Wide Climate Risk Assessment (Bureau of 
Reclamation 2011) has been completed, but the focus of this study

[[Page 62727]]

was downscaled surface water projections for major river systems in the 
West. As such, it is less useful for predicting upland effects from 
future climate change scenarios, although stream flow is highly 
correlated with precipitation and temperature, which also affect upland 
ecosystems. Downscaled climate projections represent a consensus of 
multiple climate models, but climate models alone are not able to 
account for the myriad of biological processes that may affect a 
species that only inhabits a narrow range, as local effects may reduce 
or amplify the large-scale patterns that are projected over the larger 
spatial resolution of the global climate models (Ray et al. 2010, p. 
24). In summary, global and regional climate models can play an 
important role in characterizing general changes to climate, which is a 
major determinant of species distributions, so that the potential 
impacts on natural systems can be assessed (Shafer et al. 2001, p. 
213). However, they are less able to assess local impacts to species 
with a limited range, such as the three plants discussed in this 
finding.
    Climate change is likely to affect the long-term survival and 
distribution of native species, such as Amoreuxia gonzalezii, through 
changes in temperature and precipitation. Hot extremes, heat waves, and 
heavy precipitation will increase in frequency, with the Southwest 
experiencing the greatest temperature increase in the continental 
United States (Karl et al. 2009, pp. 28, 129). In the southwestern 
United States, average temperatures increased approximately 1.5 [deg]F 
(0.8 [deg]C) compared to a 1960 to 1979 baseline (Karl et al. 2009, p. 
129). By the end of this century, temperatures are expected to warm a 
total of 4 to 10 [deg]F (2 to 5 [deg]C) in the Southwest (Karl et al. 
2009, p. 129).
    Annual mean precipitation levels are expected to decrease in 
western North America and especially the southwestern States by 
midcentury (IPCC 2007, p. 8; Seager et al. 2007, p. 1181). The levels 
of aridity of recent drought conditions and perhaps those of the 1950s 
drought years will become the new climatology for the southwestern 
United States (Seager et al. 2007, p. 1181). As mentioned previously, 
southern Arizona is currently experiencing drought conditions, and 
there has been a decline in winter precipitation over the last 34 
years.
    Atmospheric levels of carbon dioxide are expected to double before 
the end of the 21st century, which may increase the dominance of 
invasive grasses leading to increased fire frequency and severity 
across western North America (Brooks and Pyke 2002, p. 3; IPCC 2002, p. 
32; Walther et al. 2002, p. 391). Elevated levels of carbon dioxide 
lead to increased invasive annual plant biomass, invasive seed 
production, and pest outbreaks (Smith et al. 2000, pp. 80-81; IPCC 
2002, pp. 18, 32; Ziska et al. 2005, p. 1328) and will put additional 
stressors on rare plants already suffering from the effects of elevated 
temperatures and drought.
    In summary, climate change is affecting and will affect temperature 
and precipitation events in the future. We expect that Amoreuxia 
gonzalezii may be negatively affected by climate change with respect to 
drought or alteration in summer precipitation. However, we believe that 
A. gonzalezii is adapted to arid conditions, and the species has 
survived previous periods of low summer rainfall in Arizona. Although 
we believe climate change will impact plants in the future, the best 
available information does not allow us to determine the magnitude and 
scope of the potential effects on a local scale to A. gonzalezii, and 
therefore, we conclude that climate change is not a threat to the 
continued existence of this species, nor is it likely to become so.
Summary of Factor A
    In conclusion, based on our review of the best available scientific 
and commercial information, we have determined that nonnative invasive 
species, fire, development, mining, and watershed degradation are not 
threats to Amoreuxia gonzalezii. Nonnative invasive species are not 
present in or near A. gonzalezii populations; therefore, they are not a 
threat to the species. The best available information does not indicate 
that fire, development, mining, or watershed degradation are threats to 
the species. Drought may influence the population structure of A. 
gonzalezii, but we conclude that drought is not a threat to the species 
because the species has some adaptations for living in arid 
environments and has survived periods of reduced summer precipitation. 
We acknowledge that climate change, particularly the predictions of 
less frequent, but perhaps more intense, summer precipitation, and 
increasing temperatures in the Southwest, will affect individuals 
populations of A. gonzalezii. However, the species is adapted to arid 
conditions, and therefore we have determined that climate change is not 
a threat to A. gonzalezii. Thus, the present or threatened destruction, 
modification, or curtailment of its habitat or range is not a threat to 
A. gonzalezii.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Hodgson (2001, p. 91) notes that roots, young leaves, fruits, and 
seeds of Amoreuxia gonzalezii are edible. She says that, historically, 
the plant had been collected in great amounts and was ``once an 
important food source to various southwestern people.'' For example, 
the Onavas Pimas Tribe historically harvested this species frequently, 
although more recently, harvest is only incidental (Hodgson 2001, p. 
92). The tubers are collected and roasted by the Seri Indians on 
Tiburon Island, and by residents of Baja California. Evidently, the 
tubers of this species can be broken up and new plants will grow from 
the tuber pieces. In 1959, the noted anthropologist Homer Aschmann 
(Hodgson 2001, p. 94) observed with the similar and sympatric species 
Amoreuxia palmatifida that ``when the larger aboriginal population 
[native peoples of Mexico] exploited more regularly the flats where 
they grow, a larger yield of roots may have been maintained,'' implying 
that local peoples who relied on Amoreuxia for food may have enhanced 
populations by disturbing the soil and cutting roots. He stated that 
areas that were visited more regularly looked as if they had been 
plowed; the more disturbance, the more A. palmatifida grew. Both A. 
palmatifida and A. gonzalezii were historically, and continue to be, 
used by native peoples in a similar fashion, although we are unaware of 
this type of harvesting in Arizona. In summary, A. gonzalezii plants 
and roots have been used historically in parts of Mexico. There is no 
information regarding the current use of this species in Mexico, or its 
use in Arizona. Therefore, based on our review of the best available 
information, we have determined that collection of the plants or the 
roots is not a threat to A. gonzalezii, or is likely to become so.
    Amoreuxia gonzalezii is not a plant of horticultural interest. 
There is no documentation of any instances where A. gonzalezii was 
collected from the wild other than as voucher specimens to document 
occurrences (https://ag.arizona.edu/herbarium) or seed collection for 
the purposes of conserving the species. Therefore, based on the best 
available information, we have determined that collection is not a 
threat to the continued existence of the species, or is likely to 
become so.

Factor C. Disease or Predation

    There is no information indicating that disease affects Amoreuxia

[[Page 62728]]

gonzalezii. However, A. gonzalezii is very palatable to cattle and 
other ungulates (Hodgson 2001, p. 94). While some of the known 
locations in Arizona occur on steep limestone cliffs largely precluding 
cattle herbivory, plants in other locations are more susceptible. 
Hodgson (1989, p. 2) noted finding Amoreuxia plants in the Devil's 
Cashbox area with inflorescences (flowers) eaten. She was unable to 
ascertain if these plants were A. gonzalezii, or the more common A. 
palmatifida because the plants had no fruit (Hodgson 1989, p. 2). She 
also noted 13 missing plants from the Devil's Cashbox area just weeks 
after a previous site visit in 1990 (Hodgson 1989, p. 7). It is unknown 
how susceptible populations in Mexico are to grazing pressure. During a 
1988 visit to a population of A. gonzalezii outside of Moctezuma, 
Sonora, Hodgson (1989, p. 2) noted that most plants had been browsed or 
grazed. Grazing precludes sexual reproduction and, if it occurs on a 
frequent basis, may lead to reduced seed production (Hodgson 1994, p. 
9). However, A. gonzalezii also reproduces asexually; hence, the 
populations are not totally dependent on seed production for 
reproduction (Hodgson 2001, p. 94). Our review of the best available 
information did not produce any evidence that the long-term viability 
of A. gonzalezii populations in Arizona and Mexico has been affected by 
grazing, and therefore, we conclude that grazing is not a threat to 
this species.
    It has been suggested that javelinas (hoofed mammals in the peccary 
family) dig up the roots of Amoreuxia gonzalezii and that this may 
constitute a threat to the species (NatureServe 2010). The Service 
(2011a, p. 1) saw no evidence of this during the 2011 site visit, and 
there is no information available on how often javelina dig up the 
plants, or on what the long-term effects are to the populations. In 
addition, if the plants respond to digging by producing more plants, 
javelinas rooting in the soil may promote asexual reproduction. 
Therefore, after review of the best available information, we conclude 
that javelina digging up the plants and eating the roots of A. 
gonzalezii is not a threat to the species.
    Based on the best available information, we have determined that 
disease and predation are not threats to the continued existence of 
Amoreuxia gonzalezii, nor are they likely to become so.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    Amoreuxia gonzalezii is not protected by Arizona Native Plant Law 
(Arizona Revised Statutes, Chapter 7 1993, entire). It does not appear 
under any of the law's four categories of protection, although 
previously it was given consideration to be included for protection 
within the ``Salvage Restricted Protected Native Plants'' (Hodgson 
1994, p. 9), a level of protection that Hodgson considered inadequate. 
It was, however, never placed on this list (Hodgson 2011, pers. comm.). 
This means that the populations that occur on private land in Arizona 
have no protections. However, regardless of any protection under the 
Arizona Native Plant Law, our five-factor analysis suggests that A. 
gonzalezii populations are not subject to negative impacts at such a 
level that would place the species at risk. Evidence of this can be 
found in the Thomas Canyon population, which is on private property, 
and remains intact, as evidenced by surveys completed this year. 
Although A. palmatifida and A. wrightii are on the list of protected 
animals and plants for Mexico, A. gonzalezii is not listed and 
therefore receives no management considerations within its Mexican 
range (SEMARNAT 2008). Even so, we have determined that populations in 
Mexico are not subject to negative impacts at a level that would place 
the species overall at risk.
    Amoreuxia gonzalezii is considered by the Forest Service to be a 
``sensitive species'' in the Coronado National Forest. A sensitive 
species is defined as one not yet warranting listing as endangered or 
threatened, but which is sufficiently rare that its future survival is 
of concern (Forest Service Manual (FSM) 2670). The management of 
sensitive species is described in FSM 2670, and the management 
objectives are to develop and implement management practices to ensure 
that species do not become endangered or threatened because of Forest 
Service actions; maintain viable populations of all native and desired 
nonnative wildlife, fish, and plant species in habitats distributed 
throughout their geographic range on National Forest System lands; and 
develop and implement management objectives for populations or habitat 
of sensitive species or both.
    In addition, the Forest Service has to consider the effects of 
their actions on the viability of sensitive species through the 
National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et. seq.) 
process. As defined by Forest Service policy, actions must not result 
in loss of species viability or create significant trends toward the 
need for Federal listing. A. gonzalezii receives these protective 
measures through NEPA on Coronado National Forest land.
    In summary, Amoreuxia gonzalezii populations in the Coronado 
National Forest are protected by their status as sensitive species. We 
believe that the requirement to consider the species' long-term 
viability in the NEPA planning process provides adequate protection for 
the populations of A. gonzalezii in the Coronado National Forest. Any 
one factor in our analysis may constitute a threat; however, it is the 
combined analysis of all the potential threats to the species that 
determine whether a species warrants listing as an endangered or 
threatened species under the Act. In this case, there is no indication 
of actions or potential threats to the species on private land or in 
Mexico that rise to a level such that listing is warranted. As such, we 
conclude that the best available information indicates that A. 
gonzalezii is not threatened by inadequate existing regulatory 
mechanisms.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

    Amoreuxia gonzalezii has been classified as the global rank of G1, 
Critically Imperiled, by NatureServe (2010) due to the small number of 
small populations globally, palatability to cattle, and threat of 
exotic annual grasses. Even though there are only 2 occurrences in the 
United States, there seem to be at least 12 occurrences in Mexico. 
There have been no systematic surveys in Mexico, and very few 
population estimates.
    Information on a species' rarity is relevant to the conservation 
status of a species. Generally speaking, a species that has a 
geographically restricted range is likely to be more susceptible to 
environmental threats (e.g., fire, flood, drought, human land use), 
should they occur, than a species that is not rare, because one fire or 
flood could affect a larger total percentage of the range of a rare 
species than of a widespread species. However, there is no available 
information in this case to evaluate whether any environmental threats 
are currently acting upon this potentially rare species in a negative 
way, or are reasonably likely to act on it in the future. The fact that 
a rare species is potentially vulnerable to stochastic processes does 
not necessarily mean that it is reasonably likely to experience, or 
have its status affected by, a given

[[Page 62729]]

stochastic process within timescales that are meaningful under the Act.
    A species that has always been rare, yet continues to survive, 
could be well-equipped to continue to exist into the future. Many 
naturally rare species have persisted for long periods within small 
geographic areas, and many naturally rare species exhibit traits that 
allow them to persist despite their small population sizes. 
Consequently, the fact that a species is rare does not necessarily 
indicate that it may be in danger of extinction in the foreseeable 
future.
    The best available information provides no evidence that effects 
often associated with small populations that were not naturally rare, 
such as inbreeding depression or genetic drift, may be occurring in A. 
gonzalezii populations. There is also no evidence that potential 
effects to the species or its habitat may be more significant than 
historically present such that a naturally rare species, such as A. 
gonzalezii, would be at risk. Therefore, we conclude that overall 
rarity and small population size are not a threat to A. gonzalezii, nor 
are they likely to become so.

 Finding for Amoreuxia gonzalezii

    As required by the Act, we evaluated the five factors in assessing 
whether Amoreuxia gonzalezii is endangered or threatened throughout all 
or a significant portion of its range. We examined the best scientific 
and commercial information available regarding the past, present, and 
future threats faced by A. gonzalezii. We reviewed the petition, 
information available in our files, other available published and 
unpublished information, and we consulted with recognized species 
experts.
    There are no obvious threats to Amoreuxia gonzalezii or its 
habitat. The species has been used historically as a food source by 
indigenous people, but we have no information that collection and use 
of the plants and tubers are currently a threat to the species or 
likely to become so. Long-term drought and reduced summer rainfall will 
likely affect individual plants and populations. However, the plants 
are tolerant of moderate disturbance, and the species is adapted to 
arid condition, as evidenced by the plants' survival during recent 
periods of reduced summer rainfall. Based on the limited information 
available, we conclude that drought is not threat to this species or 
likely to become so. Climate change will likely affect the status of A. 
gonzalezii in the future; however, the limited information available 
that can be applied at a local scale does not suggest that climate 
change is likely to threaten the species. Regarding other factors 
potentially affecting A. gonzalezii, including nonnative, invasive 
species; fire; development; mining; and watershed degradation, the best 
available scientific information provides no evidence indicating that 
they are currently threatening the species or likely to do so in the 
future. Similarly, there is no evidence that overutilization, disease, 
or predation are affecting this species. In addition, we have 
determined that small population size is also not a threat to the 
species because the species appears to be naturally rare and there are 
no potential threats acting on the species above historical levels. 
Further, because we have determined there are no threats on the 
species, and none likely, existing regulatory mechanisms are adequate.
    Based on our review of the best available scientific and commercial 
information pertaining to the five factors, we find that the potential 
threats are not of sufficient imminence, intensity, or magnitude to 
indicate that Amoreuxia gonzalezii is in danger of extinction 
(endangered) or likely to become endangered within the foreseeable 
future (threatened), throughout all of its range.

Significant Portion of the Range

    Having determined that Amoreuxia gonzalezii is not in danger of 
extinction, or likely to become so, throughout all of its range, we 
must next consider whether there are any significant portions of the 
range where A. gonzalezii is in danger of extinction or is likely to 
become endangered in the foreseeable future.
    The Act defines an endangered species as one ``in danger of 
extinction throughout all or a significant portion of its range,'' and 
a threatened species as one ``likely to become an endangered species 
within the foreseeable future throughout all or a significant portion 
of its range.'' The term ``significant portion of its range'' is not 
defined by the statute. For the purposes of this finding, a portion of 
a species' range is ``significant'' if it is part of the current range 
of the species, and it provides a crucial contribution to the 
representation, resiliency, or redundancy of the species. For the 
contribution to be crucial, it must be at a level such that, without 
that portion, the species would be in danger of extinction. We also 
considered the historical range of the species, and have determined 
that the current range is no different from the historical range. 
Therefore, there has been no loss of the historical range, and no 
further analysis of the historical range is required.
    In determining whether Amoreuxia gonzalezii is endangered or 
threatened in a significant portion of its range, we considered status 
first to determine if any threats or potential threats acting 
individually or collectively endanger or threaten the species in a 
portion of its current range. We evaluated the current range of A. 
gonzalezii to determine if there is any apparent geographic 
concentration of the primary stressors potentially affecting the 
species including nonnative, invasive plants; fire; development; 
mining; watershed degradation; and drought. We have analyzed the 
stressors to the degree possible, and determined that they are 
essentially uniform throughout the species' range. We also found the 
stressors are not of sufficient imminence, intensity, magnitude, or 
geographically concentrated such that it warrants evaluating whether a 
portion of the range is significant under the Act. We do not find that 
A. gonzalezii is in danger of extinction now, nor is likely to become 
endangered within the foreseeable future, throughout all or a 
significant portion of its range. Therefore, listing A. gonzalezii as 
an endangered or threatened species under the Act is not warranted at 
this time.
    We request that you submit any new information concerning the 
distribution and status of, or threats to, Amoreuxia gonzalezii to our 
U.S. Fish and Wildlife Service Office (see ADDRESSES section) whenever 
it becomes available. New information will help us monitor A. 
gonzalezii and encourage its conservation. If an emergency situation 
develops for A. gonzalezii, or any other species, we will act to 
provide immediate protection.

Species Information for Astragalus hypoxylus

Species Description

    Barneby (1964, pp. 1028-1029) and Warren et al. (1991, pp. 3-4) 
describe Astragalus hypoxylus as an herbaceous perennial, in the 
Fabaceae (Pea) family. The species forms a compact mat of stems that 
typically lay flat against the ground, although the outer ends of the 
stems may turn up. The mat can be up to 15 cm (6 in) in diameter. The 
species forms a tap root that is dense and fibrous. The alternate 
leaves are compound with 11 to 13 ovate leaflets that are each 2 to 4.5 
millimeters (mm) (0.1 to 0.2 in) long. The leaflets are bicolored; the 
undersides are gray with sparse tiny hairs; the tops of the leaflets 
are yellowish-green, smooth, and

[[Page 62730]]

hairless. The leaflets have a distinct fold along the midrib.
    The inflorescence is very compact and ball-shaped, approximately 1 
cm (0.4 in) in diameter and 1 to 1.5 cm (0.4 to 0.6 in) long and looks 
somewhat like clover flowers. The flowers are approximately 6 mm (0.2 
in) long with petals that are whitish, with light purple tips. The 
flower stalks are erect above the vegetative mat. Fruits are small, 
oval pods 7 to 9 mm (0.3 to 0.35 in) long and 2 to 2.5 mm (0.1 to 0.16 
in) diameter. The pods are yellowish at the base and purplish towards 
the tip when ripe. The pods do not split open, but drop whole from the 
plant (Warren et al. 1991, pp. 3-4).
    Astragalus hypoxylus most closely resembles A. parvus (no common 
name) and A. nothoxys (sheep milkvetch). Astragalus parvus is only 
known from Mexico, but A. nothoxys may be found with A. hypoxylus 
(Johnson et al. 1992, p. 3). There are field characteristics that 
differentiate the two species. A. nothoxys has much longer flowering 
stalks, and the inflorescence is spread out along the flowering stems, 
unlike the compact, clover-like flowers of A. hypoxylus. The seed pods 
of A. nothoxyus are longer, narrower, three-sided, and green when fully 
ripe, while those of A. hypoxylus are oval and yellowish-purple when 
ripe. There has never been any disagreement in the scientific 
literature regarding the taxonomy of this species; thus we consider A. 
hypoxylus to be a valid taxon and a listable entity.

Habitat and Biology

    Levin (1987, pp. 170-171) described the habitat that supports 
Astragalus hypoxylus as ``stony openings in pine-oak juniper woodland, 
restricted to limestone derived soils.'' Van Devender (1986, pers. 
comm.) noted the same type of habitat, on a south-to-southwest 
exposure. Warren et al. (1991, p. 7) observed that A. hypoxylus is 
found in open, rocky clearings in woodlands comprised of Quercus emoryi 
(Emory oak), Q. oblongifolia (Mexican blue oak), Juniperus deppeana 
(alligator juniper), and Pinus cembroides (Mexican pinyon). The ground 
is characterized by loosely consolidated, gravelly soil composed of 
limestone and weathered rock. The plants are found at an elevation of 
approximately 1,676 m (5,500 ft) (Warren et al. 1991, p. 7). This 
habitat type is referred to as oak-savannah and is relatively common in 
the mountains of southeastern Arizona between elevations of 1,370 to 
1,830 m (4,494 to 6,000 ft) (Brown 1982, p. 59).
    Astragalus hypoxylus produces flowers in the spring (April-May), 
with fruits maturing approximately 3 weeks after the onset of flowering 
(Johnson et al. 1992, p. 5). Pollination studies on different species 
of Astragalus (Karron 1988, p. 332; Sugden 1985, pp. 303-304; Green and 
Bohart 1975, pp. 383-384; Geer et al. 1995, p. 23) reported that 
several bee species in the genera Bombus, Osmia, and Anthophora were 
the primary pollinators. However, there have been no studies on the 
pollinators for A. hypoxylus.
    The pods of Astragalus hypoxylus do not split open when ripe and 
usually fall to the ground near the parent plant. However, the pods are 
light and may be blown to other locations by the wind (Johnson et al. 
1992, p. 6). Seedlings are often detected in open places away from the 
parent plants; however, nothing is known regarding seed dispersal of 
this species (Falk, 2011, pers. obs.).
    Germination studies of Astragalus hypoxylus were carried out by the 
Desert Botanical Garden (Garden) as part of the Center for Plant 
Conservation National Collection program for conserving rare plants and 
their germplasm. Seeds were collected from the Harshaw and Bear Canyon 
populations in 1991 and 1992. During the seed collection trips, the 
biologists noted that ``plants were frequent along disturbed areas 
(erosion cuts, dirt roads)'' (Pritchett-Kozak and Ecker 1992, p. 20). 
Two germination tests were done in 1992, with germination rates of 66 
and 76 percent (Pritchett-Kozak and Ecker 1992, p. 20). Tests done in 
1991 with fresh seed and previously frozen seed were used, and the 
germination rates were high for both sets of seeds, indicating that 
freezing does not interfere with seed viability. Germination took place 
during an average daytime temperature range of 73 to 86 [deg]F (23 to 
30 [deg]C) (Ecker 1991, p. 1). These warm daytime temperatures may 
indicate that the seeds germinate in the summer, in response to summer 
rainfall, rather than in the winter. Also, the seeds readily germinated 
in August, indicating that there is no summer dormancy for these seeds 
(Ecker 1991, p. 1). Currently, there are approximately 14,000 seeds in 
frozen storage at the Garden and the National Seed Storage Lab in Ft. 
Collins, Colorado (https://www.centerforplantconservation.org). These 
seeds are available for re-introduction efforts or augmentation of 
existing populations.
    In 1993, plants produced from collected seed were initiating floral 
buds in the greenhouse by February 20. These were plants that were 
produced from previous seedling experiments. On March 16, the plants 
were placed outside on the grounds of the Garden, underneath native 
trees. The plants began flowering profusely by early April. Open 
pollination (plants were left in the open and pollination occurred 
naturally) was successful, and the plants were producing numerous 
fruits by April 20. There was no indication of pollinators in the area. 
Plants that had been previously left in the greenhouse had not produced 
seed, probably due to a lack of pollinators in the greenhouse. 
Controlled cross-pollination of two plants (two flowers per plant) was 
conducted on April 13, which resulted in two fruits per plant 
(Pritchett-Kozak 1993, p. 20). Earlier attempts at self-pollination 
failed, but the technique (use of a small paintbrush to transfer the 
pollen) may not have been optimal (Pritchett-Kozak and Ecker 1992, p. 
21). The results of the open pollination and the controlled cross-
pollination experiment likely indicate that Astragalus hypoxylus is an 
obligate outcrosser (Pritchett-Kozak 1993, p. 20).
    In conclusion, there is not a great deal of information on the 
biology and ecology of this species. The pollinators of the species are 
unknown; it is surmised that the plants are obligate outcrossers, and 
that pollination takes place in the field because fruit and seeds are 
produced. It is not known how seed is dispersed. Based on the 
germination experiments conducted by the Desert Botanical Garden, the 
best available information suggests that plants germinate in response 
to summer rainfall. Also, there is some anecdotal information that 
these plants occupy disturbed areas and may be tolerant of moderate 
disturbance.

 Distribution, Abundance, and Trends

    Astragalus hypoxylus was first collected by J. G. Lemmon in 1882 in 
Cochise County, Arizona, at a location described as ``Mahoney's Ranch, 
near Ft. Huachuca.'' (Johnson et al. 1992, p. 4). This site description 
proved to be so vague that this area was never able to be located again 
(Johnson et al. 1992, p. 4). The species was not detected again until 
1986, when it was collected in the Patagonia Mountains, approximately 
4.5 kilometers (km) (2.8 miles (mi)) south of Harshaw on the road to 
Washington Camp, in the Coronado National Forest (Levin 1987, pp. 170-
171). Later in 1986, botanists visited this same location and counted 
approximately 107 plants in the area, again noting that the plants were 
``common in grassy openings in oak woodland on relatively steep slopes 
with coarse sandy soils'' (Van Devender 1986, pers. comm.; Kennedy 
1986, pers. comm.). In 1991, Malusa et al. (1992, p. 25) found two 
additional populations in the Patagonia

[[Page 62731]]

Mountains, near the Harshaw site. Approximately 180 plants were found 
in adjacent canyons. These populations are within a couple of miles of 
the Harshaw site and, for the purposes of this finding, will be 
referred to as the Harshaw2 populations.
    In addition, many surveys were undertaken by staff at the Nature 
Conservancy and other botanical contractors to the Coronado National 
Forest,