Endangered and Threatened Wildlife and Plants; Listing Roswell springsnail, Koster's springsnail, Noel's amphipod, and Pecos assiminea as Endangered With Critical Habitat, 46304-46333 [05-15486]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 70, Number 152 (Tuesday, August 9, 2005)]
[Rules and Regulations]
[Pages 46304-46333]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-15486]



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Part III





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Listing Roswell 
springsnail, Koster's springsnail, Noel's amphipod, and Pecos assiminea 
as Endangered With Critical Habitat; Final Rule

Federal Register / Vol. 70, No. 152 / Tuesday, August 9, 2005 / Rules 
and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AI15


Endangered and Threatened Wildlife and Plants; Listing Roswell 
springsnail, Koster's springsnail, Noel's amphipod, and Pecos assiminea 
as Endangered With Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), list the 
Roswell springsnail (Pyrgulopsis roswellensis), Koster's springsnail 
(Juturnia kosteri), and Noel's amphipod (Gammarus desperatus) as 
endangered and the Pecos assiminea (Assiminea pecos) as endangered with 
critical habitat under the Endangered Species Act of 1973, as amended 
(Act). These four invertebrates occur at sinkholes, springs, and 
associated spring runs and wetland habitats. They are found at one site 
in Chaves County, New Mexico, and Pecos assiminea is also found at one 
site in Pecos County, Texas, and one site in Reeves County, Texas.
    These three snails and one amphipod have an exceedingly limited 
distribution, low mobility, and fragmented habitat. They are imperiled 
by introduced species, surface and groundwater contamination, oil and 
gas extraction activities within the supporting aquifer and watershed, 
local and regional groundwater depletion, severe drought, and direct 
loss of their habitat (e.g., through burning or removing marsh 
vegetation, or flooding of habitat). This final rule will implement the 
Federal protection and recovery provisions of the Act for these 
invertebrate species. We are also designating critical habitat for the 
Pecos assiminea in Texas.

DATES: This final rule is effective September 8, 2005.

ADDRESSES: Supporting documentation for this rulemaking is available 
for public inspection, by appointment, during normal business hours at 
the U.S. Fish and Wildlife Service, New Mexico Ecological Services 
Field Office, 2105 Osuna Road NE., Albuquerque, New Mexico 87113.

FOR FURTHER INFORMATION CONTACT: Susan MacMullin, Field Supervisor, New 
Mexico Ecological Services Field Office (telephone, 505-761-4706; 
facsimile, 505-346-2542).

SUPPLEMENTARY INFORMATION:

Background

    It is our intent to discuss only those topics directly relevant to 
this final listing determination. For more information on the four 
invertebrates, refer to the February 12, 2002, proposed rule (67 FR 
6459). However, some of this information is discussed in our analyses 
below, such as the summary of factors affecting the species.

Springsnails

    The Permian Basin of the southwestern United States contains one of 
the largest carbonate (limestone) deposits in the world (New Mexico 
Department of Game and Fish (NMDGF) 1998). Within the Permian Basin of 
the Southwestern United States lies the Roswell Basin. Located in 
southeastern New Mexico, this Basin has a surface area of around 31,080 
square kilometers (km) (12,000 square miles [mi]) and generally begins 
north of Roswell, New Mexico, and runs to the southeast of Carlsbad, 
New Mexico. The Roswell Basin contains a deep artesian aquifer and a 
shallow surficial aquifer. The action of water on soluble rocks (e.g., 
limestone and dolomite) has formed abundant ``karst'' features such as 
sinkholes, caverns, springs, and underground streams (White et al. 
1995). These hydrogeological formations create unique settings 
harboring diverse assemblages of flora and fauna. The isolated 
limestone and gypsum springs, seeps, and wetlands located in and around 
Roswell, New Mexico, and Pecos and Reeves Counties, Texas, provide the 
last known habitats in the world for several endemic species of fish, 
plants, mollusks, and crustaceans. These species include the Roswell 
springsnail and Koster's springsnail of the freshwater snail family 
Hydrobiidae, Pecos assiminea of the snail family Assimineidae, and 
Noel's amphipod (Gammaridae). These species are distributed in 
isolated, geographically separate populations, and likely evolved from 
parent species that once enjoyed a wide distribution during wetter, 
cooler climates of the Pleistocene. Such divergence has been well-
documented for aquatic and terrestrial macroinvertebrate groups within 
arid ecosystems of western North America (e.g., Taylor 1987; Metcalf 
and Smartt 1997; Bowman 1981; Cole 1985).
    North American snails of the family Hydrobiidae inhabit a great 
diversity of aquatic systems from surface to cave habitats, small 
springs to large rivers, and high energy riffles to slack water pools 
(Wu et al. 1997). Snails of the family Assimineidae are typically found 
in coastal brackish waters or along tropical and temperate seacoasts 
worldwide (Taylor 1987). Inland species of the genus Assiminea are 
known from around the world, and in North America they occur in 
California (Death Valley National Monument), Utah, New Mexico, Texas 
(Pecos and Reeves Counties), and Mexico (Bols[oacute]n de Cuatro 
C[iacute]enegas).
    The Roswell springsnail and Koster's springsnail are aquatic 
species. These snails have lifespans of 9 to 15 months and reproduce 
several times during the spring through fall breeding season (Taylor 
1987; Pennak 1989; Brown 1991). Snails of the family Hydrobiidae are 
sexually dimorphic (there are characteristic differences between males 
and females), with females being characteristically larger and longer-
lived than males. As with other snails in the family, the Roswell 
springsnail and Koster's springsnail are completely aquatic but can 
survive in seepage areas, as long as flows are perennial and within the 
species' physiological tolerance limit. These two snails occupy spring 
heads and runs with variable water temperatures (10 to 20 [deg] Celsius 
[C] (50 to 68 [deg] Fahrenheit [F])) and slow-to-moderate water 
velocities over compact substrate ranging from deep organic silts to 
gypsum sands and gravel and compact substrate (NMDGF 1998). Conversely, 
the Pecos assiminea seldom occurs immersed in water, but prefers a 
humid microhabitat created by wet mud or beneath vegetation mats, 
typically within a few centimeters (cm) (inches (in)) of running water.
    Gastropods (snails) are a class of mollusks with a body divided 
into a foot and visceral mass and a head that usually bears eyes and 
tentacles. Like most gastropods, the Roswell springsnail, Koster's 
springsnail, and Pecos assiminea feed on algae, bacteria, and decaying 
organic material (NMDGF 1988). They will also incidentally ingest small 
invertebrates while grazing on algae and detritus (dead or partially 
decayed plant materials or animals).
    These snails are fairly small; Koster's springsnail is the largest 
of the three snails, and is about 4 to 4.5 millimeters (mm) (0.16 to 
0.18 in) long with a pale tan shell that is narrowly conical with up to 
4\1/4\ to 5\3/4\ whorls or twists. The Roswell springsnail is 3 to 3.5 
mm (0.12 to 0.14 in) long with a narrowly conical tan shell with up to 
5 whorls. Pecos assiminea is the smallest of the three, with a shell 
length of 1.55 to 1.87 mm (0.06 to 0.07 in) and a thin, nearly 
transparent chestnut-brown shell that is regularly conical with up to 
4\1/2\ strongly incised (shouldered) whorls and a broad oval opening. 
Although their shells are

[[Page 46305]]

similar, the Roswell springsnail is distinguished from Koster's 
springsnail by a dark, amber operculum (a lid which closes the shell 
opening when the animal is retracted) with white spiral streaks, while 
that of Koster's springsnail is nearly colorless. The genus Assiminea 
can be determined from other snail genera by an almost complete lack of 
tentacles, leaving the eyes within the tips of short eye stalks (Taylor 
1987).
    Taylor (1987) first described the Roswell springsnail from a 
``seepage'' along the west side of an impoundment in Area 7 at Bitter 
Lake National Wildlife Refuge (BLNWR, Refuge), Chaves County, New 
Mexico. Since then, Mehlhop (1992, 1993) has documented the species on 
the BLNWR and in March 1995 also found it in a spring on private land 
(i.e., North Spring) east of Roswell (NMDGF 1998). In 2004, the Roswell 
springsnail was determined to have been extirpated from this private 
land through habitat alteration (NMDGF 2005b). Monitoring efforts at 
BLNWR (1995 to 1998) led to the discovery of Roswell springsnail 
populations in Bitter Creek, the Sago Springs Complex, and a drainage 
canal along the west shoreline of Area 6. The Roswell springsnail is 
currently known only from BLNWR with the core population in the Sago 
Springs Complex and Bitter Creek. The Sago Springs complex is 
approximately 0.3 km long (1,000 linear feet), half of which is 
subterranean with flow in the upper reaches restricted to sinkholes. 
Bitter Creek is six times longer than the Sago Springs Complex and has 
a total length of 1.8 km (1.1 miles). Monthly monitoring and ecological 
studies of the Roswell springsnail initiated at BLNWR in June 1995 are 
ongoing (NMDGF 2005b, 2005c).
    Roswell springsnail formerly occurred in several other springs in 
the Roswell area, but these habitats have dried up apparently due to 
groundwater pumping and no longer contain the species (Cole 1981; 
Taylor 1983, 1987). As noted, the Roswell springsnail historically 
occurred on private land at North Spring, but could not be found during 
surveys in 2004 (NMDGF 2005b). Pleistocene fossils of the Roswell 
springsnail are known from Berrendo Creek and the Pecos River in Chaves 
County (Taylor 1987). No populations are currently known from these 
areas.
    Taylor (1987) first reported Koster's springsnail from Sago Spring 
at BLNWR. Another population was documented in 1995 at North Spring on 
private land east of Roswell and a second population was found at BLNWR 
on the west side of Area 3 during extensive surveys conducted between 
1998 and 2001 (Warrick 2005). The species formerly occurred in several 
other springs in the Roswell area, but these habitats have since dried 
up due to groundwater pumping and no longer contain the species (Cole 
1981; Taylor 1983, 1987; NMDGF 2005b). Pleistocene fossils of Koster's 
springsnail are known from North Spring River and South Spring Creek in 
Chaves County (Taylor 1987). Monthly monitoring and ecological studies 
of Koster's springsnail initiated at BLNWR in 1995 indicate the species 
is most abundant in the deep organic substrates of Bitter Creek (NMDGF 
1998, 2005b). It also occurs at the Sago Springs Complex, but in lower 
numbers. The species has not been found in recent times along the 
western boundary of Area 3 in BLNWR (NMDGF 2005b). Koster's springsnail 
has recently been extirpated at North Spring east of Roswell (NMDGF 
2005b).
    Pecos assiminea is presently known from two sites at BLNWR, Chaves 
County, New Mexico, from a large population at Diamond Y Spring and its 
associated drainage (Diamond Y Springs Complex), Pecos County, Texas, 
and at East Sandia Spring, Reeves County, Texas. It was thought that 
Pecos assiminea occurred sporadically throughout the Bolson de Cuatro 
Cinegas, Coahuila, Mexico (Taylor 1987); however, recent investigations 
indicate that the population in Mexico might be a different species 
(Hershler 2005). Investigations are currently underway to determine 
whether the animals found in the vicinity of Coahuila, Mexico, are 
Pecos assiminea (Hershler 2005).
    Monitoring and ecological studies of Pecos assiminea initiated at 
BLNWR in 1995 showed the snail to be typically absent from substrate 
samples. Populations of Pecos assiminea occur sporadically along Bitter 
Creek, and a dense population was confirmed on moist vegetation and on 
muddy surfaces within 1 cm (0.39 in) of water in 1999 in an emergent 
marsh plant community around the perimeter of a sinkhole within the 
Sago Springs Complex (NMDGF 1999).

Noel's amphipod

    Noel's amphipod, in the family Gammaridae, is a small freshwater 
crustacean. Inland amphipods are sometimes referred to as freshwater 
shrimp. Noel's amphipod is brown-green in color with elongate, kidney-
shaped eyes, and flanked with red bands along the thoracic and 
abdominal segments, often with a red dorsal stripe. Males are slightly 
larger than females, and individuals range from 8.5 to 14.8 mm (0.33 to 
0.58 in) long (Cole 1981, 1985).
    Gammarids commonly inhabit shallow, cool, well-oxygenated waters of 
streams, ponds, ditches, sloughs, and springs (Holsinger 1976; Pennak 
1989). Because they are light-sensitive, these bottom-dwelling 
amphipods are active mostly at night and feed on algae, submergent 
vegetation, and decaying organic matter (Holsinger 1976; Pennak 1989). 
Young amphipods depend on microbial foods, such as algae and bacteria, 
associated with aquatic plants (Covich and Thorp 1991). Most amphipods 
complete their life cycle in one year and breed from February to 
October, depending on water temperature (Pennak 1978). Amphipods form 
breeding pairs that remain attached for 1 to 7 days at or near the 
substrate while continuing to feed and swim (Bousfield 1989). They can 
produce from 15 to 50 offspring, forming a ``brood.'' Most amphipods 
produce one brood but some species produce a series of broods during 
the breeding season (Pennak 1978).
    Noel's amphipod is one of three species of endemic amphipods of the 
Pecos River Basin occurring from Roswell, New Mexico, south to Fort 
Stockton, Texas, known collectively as the Gammarus-pecos complex (Cole 
1985). Noel's amphipod is currently known from the following sites at 
BLNWR: Sago Springs Complex, Bitter Creek, along the western boundary 
of Area 6, Area 7 spring-ditch, and Hunter Marsh. It is also found in a 
spring just outside the BLNWR boundary on private property owned by the 
City of Roswell (G. Warrick 2005). Noel's amphipod was first described 
by Cole (1981) from a 1967 collection of amphipods taken from North 
Spring, east of Roswell. Based on morphological similarities, specimens 
collected from Lander Springbrook near Roswell were also identified as 
Noel's amphipod (Cole 1981). The amphipod was extirpated from Lander 
Springbrook between 1951 and 1960, and the North Spring population was 
lost between 1978 and 1988. The extirpations were attributed to 
regional groundwater depletions and habitat alterations (spring 
channelization) respectively (Cole 1981, 1985).

Previous Federal Actions

    On November 22, 1985, we received a petition from Mr. Harold F. 
Olson, Director of the NMDGF, to add 11 species of New Mexican mollusks 
to the Federal list of endangered and threatened wildlife. Roswell 
springsnail (Pyrgulopsis roswellensis, formerly Fontelicella 
roswellensis (Hershler

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1994)), Koster's springsnail (Juturnia kosteri, formerly Durangonella 
kosteri and Tryonia kosteri (Hershler et al. 2002)), and Pecos 
assiminea were among the 11 species. We determined that the petition 
presented substantial information that the requested action may be 
warranted and published a positive 90-day petition finding in the 
Federal Register on August 20, 1986 (51 FR 29671). A subsequent 12-
month finding published in the Federal Register on July 1, 1987 (52 FR 
24485), concluded that the petitioned action was warranted but 
precluded by other higher priority listing actions.
    On August 29, 2001, the Service announced a settlement agreement in 
response to litigation by the Center for Biological Diversity, the 
Southern Appalachian Biodiversity Project, and the California Native 
Plant Society. Terms of the agreement required that we submit to the 
Federal Register, on or by February 6, 2002, a 12-month finding and 
accompanying proposed listing rule and proposed critical habitat 
designation for the four invertebrates addressed in this final rule. 
This agreement was entered by the court on October 2, 2001 (Center for 
Biological Diversity, et al. v. Norton, Civ. No. 01-2063 (JR) 
(D.D.C.)). A proposed rule to list the four invertebrates as endangered 
with critical habitat was published in the Federal Register on February 
12, 2002 (67 FR 6459). On May 31, 2002, we reopened the public comment 
period for 90 days (67 FR 6459). In addition, we published newspaper 
notices inviting public comment and announcing the public hearing in 
the following newspapers in New Mexico: the Carlsbad Current-Argus, the 
Artesia Daily Press, the Roswell Daily Record, and the Albuquerque 
Journal. On June 18, 2002, we held a public hearing in Carlsbad, New 
Mexico, to solicit comments on the proposed rule.
    On May 4, 2005, we announced the availability of the draft economic 
analysis and draft environmental assessment for the proposal to 
designate critical habitat for the four invertebrates (70 FR 23083). 
Section 4(b)(2) of the Act requires that we consider economic impacts, 
impacts to national security, and other relevant impacts prior to 
making a final decision on what areas to designate as critical habitat. 
We solicited data and comments from the public on these draft 
documents, as well as on all aspects of our proposal, so that we could 
consider these in this final determination.

Summary of Comments and Recommendations

    In the notices announcing the public comment periods, we requested 
that all interested parties submit comments on the proposed listings 
and critical habitat designation, as well as on the associated draft 
economic analysis and draft environmental assessment, and we also 
requested information pertaining to any actions that affect the four 
invertebrates; their current status, ecology, distribution, and 
threats; and management or conservation efforts in place. We requested 
this information in order to make a final listing determination based 
on the best scientific and commercial data currently available. We also 
solicited four independent experts who are familiar with these species 
to peer review the proposed listing and critical habitat designation. 
Two of the peer reviewers submitted substantial comments, but did not 
support or oppose the proposal. During the public comment periods, we 
also received 967 written comments (952 written comments were 
identical, in the form of automatically generated emails), and 7 
speakers gave verbal comments at the public hearing. Of those oral 
comments, one supported the proposal, two were opposed to the proposal, 
and four provided additional information. Of the written comments, 956 
supported the proposal, 8 were opposed, and 3 were neutral but provided 
information. All substantive information provided during the public 
comment periods, written and verbal, either has been incorporated 
directly into this final determination or is addressed below. Similar 
comments are grouped together by issue.

Issue 1: Biological Concerns

    (1) Comment: It is unlikely that Melanoides tuberculata, a fully 
aquatic animal, competes with Pecos assiminea, a semi-terrestrial 
species. On the other hand, the presence of introduced Melanoides 
tuberculata could pose a serious threat to aquatic species such as 
Koster's springsnail, Roswell springsnail, or Noel's amphipod.
    Our Response: The commenter is correct. It is unlikely that 
Melanoides would be a competitor with Pecos assiminea and it is very 
likely that it may be a serious threat to Koster's springsnail, Roswell 
springsnail, and Noel's amphipod. We have a more complete discussion of 
the threat of introduced species under the section, ``Summary of 
Factors Affecting the Species'' below.
    (2) Comment: The NMDGF concluded in 1999 that all four invertebrate 
species are stable on the BLNWR. There is no evidence that these 
species are at risk.
    Our Response: All four invertebrates are classified as Endangered 
by the NMDGF under the Wildlife Conservation Act of 1974 (i.e., State 
Endangered Species Act) (19 NMAC 33.6.8). As such, the NMDGF supports 
the listing and critical habitat designation for these species. They 
report that recent (1992 to present) population and habitat monitoring 
on BLNWR has documented the persistence of these species; however, they 
still face significant threats (Lang 2002, NMDGF 2005a). Our current 
understanding of the threats to the four invertebrates and their 
habitat are fully described under the ``Summary of Factors Affecting 
the Species'' section below.
    (3) Comment: Oil and gas development activities in the vicinity of 
BLNWR pose no threat to the four invertebrates because the New Mexico 
Oil Conservation Division regulations for installation of oil and gas 
wells provide protections to limit impacts.
    Our Response: The New Mexico Interstate Stream Commission (NMISC) 
and NMDGF submitted information that is consistent with the proposed 
rule, which indicated oil and gas, residential, or industrial 
development on the private lands immediately west of BLNWR may 
constitute a threat to spring water quality (Balleau et al. 1999; 
McCord et al. 2005; NMDGF 2005a) (see ``Summary of Factors Affecting 
the Species'' section below). The NMDGF also presented an overview of 
oil and gas production and potential risk to the four invertebrates 
(NMDGF 2005a). They note that, although there are no known cases of 
groundwater contamination by leaking oil or gas wells in the source-
water capture zone for the Middle Area of BLNWR (discussed further 
under ``Water Quality'' section below), groundwater contamination from 
petroleum products has been documented north of Roswell (NMDGF 2005a).
    There is a history of oil and gas industry operations on and 
adjacent to BLNWR, which have resulted in the spillage of oil and brine 
onto the BLNWR. For example, annual reports from 1994 to 1998 document 
four oil and gas related accidents on and immediately adjacent to BLNWR 
(NMDGF 2002; NMISC 2002). In May 1993, a private corporation began 
drilling a well on adjacent Bureau of Land Management (BLM) lands when 
they hit a water flow with a high chloride content (6,000 parts per 
million). The salt water was eventually contained, but serves as an 
example of

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potential issues from oil and gas development (Service 2002). 
Additionally, in 1996, about 70 to 80 barrels of oil spilled within a 
berm on an adjacent oil well located on BLM lands (Service 2002). In 
1997, an additional 11 barrels of crude oil leaked into the BLNWR 
boundary (Service 2002). In 1998, BLNWR personnel documented probable 
violations of New Mexico Oil Conservation Division regulations (e.g., a 
substandard pit for drilling cuttings, fire hazards, lack of spillage 
notification) (Service 2002; NMISC 2002). In 2000, there was an 
additional oil spill on adjacent BLM lands (NMISC 2002).
    Development of another 91 natural gas and oil wells has been 
anticipated on lands managed by the BLM within the source-water capture 
zone (NMDGF 2005a). Contamination of groundwater from underground leaks 
has the potential to occur in the future, but existing drilling and 
casing regulations by the State of New Mexico's Oil Conservation 
Division and requirements of the BLM for oil and gas drilling and 
operation in cave and karst areas (BLM 1997) are likely to 
substantially reduce this probability. The NMDGF indicates that a more 
likely pathway for petroleum-product contamination of groundwater is 
from leaking storage and transport facilities from the well site 
downstream to processing facilities (NMDGF 2005a). These may include 
leaking pipelines, overflowing storage tanks, leaking valves, and other 
sources. These data indicate that oil and gas production and 
distribution continue to threaten the four invertebrates.
    (4) Comment: Contamination threats to the four invertebrates are 
not limited to oil and gas development, but also include fire effects. 
Immediate and short-term adverse effects have been demonstrated from 
the March 2000 Sandhill Fire (NMISC 2002).
    Our Response: NMDGF recently reviewed the effects of fire on the 
invertebrates (NMDGF 2005a). We agree with their assessment and 
summarize much of the information below. We recognize that populations 
of these four invertebrates have the potential to be eliminated or 
habitat may be rendered unsuitable if fire results in complete 
combustion of vegetation and litter, high soil temperatures, 
significant amounts of ash flow, large changes in water chemistry 
(e.g., dissolved oxygen), or extensive vegetation removal resulting in 
soil and litter drying. As such, we have also revised the ``Summary of 
Factors Affecting the Species'' section below to include a more 
detailed analysis on the threat of wildfire.
    (5) Comment: Much of the literature is overly general in nature and 
is not site-or species-specific. Including such citations leaves 
readers to conclude that a particular author made a statement or 
presented data that specifically applies to the threats you believe 
exist for these invertebrates.
    Our Response: In determining and evaluating threats to the four 
invertebrates, we used the best scientific and commercial data 
available. This included articles published in peer-reviewed journals, 
data collected by NMDGF, and comments received on the proposed rule, 
draft economic analysis, and environmental assessment. You are correct 
that some of our citations are not specific to these species or the 
geographic area. Nevertheless, the citations offer evidence that 
certain threats are real for the species because similar examples have 
been documented elsewhere.
    (6) Comment: The allegation that fire caused significant decreases 
in invertebrate populations implies that quantitative sampling was 
conducted. The Service and NMDGF rarely conduct quantitative sampling, 
and the case may be overstated in your proposal.
    Our Response: Extensive quantitative pre- and post-fire monitoring 
was conducted by the NMDGF (NMDGF 2005c). Immediately following the 
Sandhill fire, Lang (2001) documented a decrease in species richness of 
localized populations of aquatic macroinvertebrates. For example, in 
1996 densities of Noel's amphipod at Dragonfly Spring were estimated at 
11,625 per square meter (m\2\). Out of 74 post-fire monitoring 
collections conducted from March 2000 to August 2004, only four Noel's 
amphipod were found (NMDGF 2005c).
    (7) Comment: Does non-native vegetation such as saltcedar (Tamarix 
sp.) threaten the invertebrates? Will New Mexico's ability to eradicate 
or manage saltcedar be restricted if these species are listed?
    Our Response: Saltcedar management or eradication activities would 
be subject to section 7 consultation requirements if a proposed project 
has the potential to affect the four invertebrate species or designated 
critical habitat. However, the environmental assessment found that some 
activities may be considered to be of benefit to the four invertebrate 
species (Service 2005). Examples of such beneficial actions could 
include removal and control of non-native vegetation, restoration of 
wetlands, and removal of non-native species.
    Non-native saltcedar is present on BLNWR and The Nature Conservancy 
(TNC) lands at the Diamond Y Spring and East Sandia Springs preserves 
(Service 2005). This non-native species is currently being controlled 
where possible by BLNWR and TNC staff. Control and removal of non-
native vegetation was identified as a factor responsible for 
extirpation of localized populations of Pecos assiminea in Mexico and 
New Mexico (Taylor 1987). However, it is possible that removal and 
control of saltcedar will improve habitat and hydrologic conditions at 
springs and seeps (Service 2005). See also ``Factor C'' under the 
``Summary of Factors Affecting the Species'' section below.
    (8) Comment: Have laboratory toxicity tests been conducted to 
determine the four invertebrates' sensitivity to low oxygen, sediments, 
or contaminants?
    Our Response: To our knowledge, laboratory tests have not been 
conducted specifically on these species to determine their sensitivity 
to low oxygen, sediments, or contaminants.
    (9) Comment: Equating the springsnails with Higgin's eye mussel is 
inappropriate. Clearly, clams and mussels are very different creatures 
than springsnails.
    Our Response: The commenter is correct that mussels that live in 
the substrate and filter water to obtain nutrition are very different 
from springsnails that crawl on the substrate and scrape periphyton 
(various forms of algae and diatoms) off the substrate. Unfortunately, 
very little research has been done specifically on the effects of 
contaminants on springsnails and mussels are one of the most closely 
related groups available for comparison. However, this reference has 
been removed from this final rule.
    (10) Comment: The relevance of South Spring River is not apparent 
in your discussion of Noel's amphipod. The South Spring River has been 
dry for many years.
    Our Response: The discussion of Noel's amphipod and the dry South 
Spring River was included to document that this previously known 
population has likely been extirpated.
    (11) Comment: Are crayfish known predators of springsnails?
    Our Response: Crayfish are known to consume aquatic macrophytes and 
algae that springsnails rely on for grazing and egg laying (Service 
2004b). In addition, crayfish have been cited as a threat and are known 
to directly prey upon aquatic invertebrates such as springsnails (e.g., 
Three Forks springsnail (Pyrgulopsis trivialis)) (Arizona Game and Fish 
Department 2003; Service 2004b). Nevertheless, we have not observed any 
crayfish within habitat occupied by

[[Page 46308]]

these four invertebrates, with the exception of Diamond Y Springs 
Complex where an undescribed native crayfish occurs. See also ``Factor 
C'' under the ``Summary of Factors Affecting the Species'' section 
below.
    (12) Comment: Effects to these species from prolonged drought, 
nutrient enrichment, and sedimentation are all unsubstantiated.
    Our Response: There is no doubt that prolonged drought leading to 
spring diminishment or drying would have a negative impact on the 
invertebrates. Little research has been done specifically on 
springsnails to document their response to elevated nutrients, 
contaminants, or sedimentation. However, based on biological principles 
and effects observed in other related invertebrates, we can draw 
reasonable conclusions about what we would expect to happen to these 
species.
    (13) Comment: Have surveys for these species been conducted at 
Bottomless Lakes State Park?
    Our Response: Surveys were conducted on Bottomless Lakes State Park 
during the 1990s by the NMDGF and during the 1980s by D.W. Taylor. 
Perennial sinks west-northwest of Lea Lake and its outflow to the 
south, which eventually flows to the BLM Overflow Wetlands, were also 
surveyed for these invertebrates (Lang 2005). Although potentially 
suitable habitat for the four invertebrates is available at Bottomless 
Lakes State Park, these surveys failed to document their occurrence 
(New Mexico Energy Minerals and Natural Resources Department 2000; 
NMDGF 2005b).
    (14) Comment: A new population of Noel's amphipod has been recently 
discovered on BLNWR.
    Our Response: The commenter is correct. Noel's amphipod currently 
persists on BLNWR at the Sago Spring wetland complex (including 
Sinkhole No. 31), Bitter Creek, and along the western boundary of Area 
6, in the west ditch along Area 7, and along the northwest fenceline of 
Hunter Marsh (NMDGF 2005c). A new population was discovered in 2004 in 
a spring belonging to the City of Roswell that borders BLNWR. This 
population is included in the listing portion of this final rule, but 
is not within the designation of critical habitat. The critical habitat 
designation does not include these private lands because section 
4(b)(4) of the Act and the Administrative Procedure Act (5 U.S.C. 551 
et seq.) requires that areas designated as critical habitat must first 
be proposed as such. Thus, we cannot make additions in this final rule 
to include areas that were not included in the proposed rule. 
Designation of such areas would require a new or revised proposal and 
subsequent final rule. Should critical habitat be considered in the 
future for the Noel's amphipod, we will consider this area in any such 
determination.
    (15) Comment: The ongoing drought appears to be more of a threat to 
these species than groundwater pumping.
    Our Response: We agree. Please refer to the ``Summary of Factors 
Affecting the Species'' for further discussion of this issue.
    (16) Comment: The proposed rule lacks documentation of groundwater 
or surface contamination threats to the four invertebrates.
    Our Response: Based upon public comments and information received, 
we have updated our analysis to include our current understanding of 
the threats from groundwater or surface contamination to the four 
invertebrates. Please see the ``Summary of Factors Affecting the 
Species'' section.
    (17) Comment: The Pleistocene Era was mentioned several times in 
the proposed rule. Does the Service intend to recover these species to 
levels that were present during this historic era?
    Our Response: No, section 4 of the Act and its implementing 
regulations (50 CFR part 424) set forth the procedures for adding 
species to the List of Endangered and Threatened Wildlife and Plants. A 
species may be determined to be endangered or threatened due to one or 
more of the five factors described in section 4(a)(1) of the Act. As 
detailed below in our analysis, we examine the listing factors and 
their application to the four invertebrates. The discussion of these 
species in relation to the Pleistocene Era was presented as evidence of 
an apparent historical decline in the numbers, range, and distribution. 
We did not intend to suggest that the four invertebrates need to be 
restored to Pleistocene Era levels to be considered recovered.
    (18) Comment: Is there a plan to control introduced or exotic 
snails or other species that may prey upon or compete with the four 
invertebrates?
    Our Response: BLNWR is managed for wildlife conservation, which 
includes restoration and maintenance of biological integrity, 
diversity, and environmental health. Major land management activities 
on BLNWR include water level management in impoundments to provide 
habitat for waterfowl, shorebirds, and other groups of species, habitat 
restoration, prescribed burning, control of saltcedar, and management 
of noxious weeds (Service 2005a). Management or removal of exotic 
species that compete with these invertebrates will be evaluated in the 
development of a recovery plan, but this management is currently 
conducted as appropriate. For example, removal of non-native fishes 
from Diamond Y Springs Complex using antimycin, netting, and trapping 
was conducted in the past for conservation of Leon Springs pupfish 
(Service 2005a). For further information and analysis concerning exotic 
species, please refer to the ``Factor C'' under the ``Summary of 
Factors Affecting the Species'' section.

Issue 2: Procedural and Legal Compliance

    (19) Comment: In the proposed rule for the four invertebrate 
species, restrictions are proposed on groundwater pumping within the 
Pecos Basin, which would have serious effects on the water supply and 
use of water by the citizens of New Mexico.
    Our Response: We disagree, the proposed rule did not propose 
restrictions on groundwater pumping. Consistent with our Interagency 
Cooperative Policy for Endangered Species Act Section 9 Prohibitions, 
published in the Federal Register on July 1, 1994 (59 FR 34272), we 
identified in the proposed rule those activities that we believe would 
or would not constitute a violation of the prohibitions identified in 
section 9 of the Act. The final Federal listing of these four 
invertebrates under the Act requires that Federal agencies consult with 
the Service on activities involving Federal funding, a Federal permit, 
Federal authorization,or other Federal actions. Consultation (under 
section 7 of the Act) is required when activities have the potential to 
affect the four invertebrates or designated critical habitat. The 
consultation will analyze and determine to what degree the species are 
impacted by the proposed action. Section 7 of the Act prohibits actions 
funded, authorized, or carried out by Federal agencies from 
jeopardizing the continued existence of a listed species or destroying 
or adversely modifying the listed species' critical habitat. This final 
Federal listing does not restrict groundwater pumping or any other 
actions.
    The environmental assessment found that spring flows within the 
proposed critical habitat on BLNWR are already protected by existing 
water rights afforded by the New Mexico Office of the State Engineer's 
administration of the Roswell Basin. In 1967, water rights were 
adjudicated in the Roswell Basin, wells were metered, and pumping rates 
administered by the Office of the State Engineer (OSE). Currently, any

[[Page 46309]]

proposed change in use of water (underground or surface depletion) in 
the Roswell Basin will undergo analysis by OSE to determine if there 
would be impairment to existing water rights (McCord et al. 2005). The 
OSE will not allow such change if it impairs the Federal water right in 
any respect (NMISC 2005). Thus the spring flows on BLNWR should be 
protected from any changes in groundwater pumping near the refuge in 
the future.
    In Texas, Pecos assiminea currently has no State or other 
regulatory protection. Some protection for the habitat of this species 
is provided with the ownership of the springs by TNC (Karges 2003). 
Groundwater pumping that could affect spring flows is subject to 
limited regulation in Texas. State agencies do not control groundwater 
pumping, and Texas courts have held that, with few exceptions, 
landowners have the right to take all the water that can be captured 
under their land (rule of capture), regardless of impacts to neighbors 
or natural resources. As noted in the economic analysis, within Texas 
further hydrological studies are necessary to determine the impact of 
groundwater pumping on surface and groundwater levels at Units 3 and 4. 
The TNC has stated that additional research on the delineation of 
watersheds is crucial to the sustainable, long-term conservation of the 
springs. If hydrological studies determine a link between the various 
aquifers, we would work with private landowners on a volunteer basis to 
minimize impacts to the Pecos assiminea from groundwater withdrawals.
    (20) Comment: The groundwater depletion analysis fails to rely upon 
the best available science, does not utilize an accurate and reliable 
model, and mischaracterizes effects of groundwater pumping.
    Our Response: Based upon new information we received during the 
comment periods, we revised our analysis from the proposed rule to 
reflect our current understanding regarding the threat of groundwater 
depletion on the four invertebrates and their habitat in New Mexico. 
Please refer to the ``Summary of Factors Affecting Species'' section.
    (21) Comment: The status of these species will not improve if they 
are listed.
    Our Response: Federal listing in and of itself does not improve the 
status of the species. Listing these species authorizes the development 
of a recovery plan. The recovery plan will likely identify both State 
and Federal efforts for conservation of these species and establish a 
framework for agencies and stakeholders to coordinate activities and 
cooperate with each other in conservation efforts. The plan will set 
recovery priorities and describe site-specific management actions 
necessary to achieve conservation and survival of the four 
invertebrates. See also response to comment 22 below for related 
information about the five factors described in section 4(a)(1) of the 
Act. Also note the discussion on section 7 consultation requirements in 
our response to comment 19 above.
    (22) Comment: Why does the Service want to list these four 
invertebrates when they are already within protected areas?
    Our Response: We have analyzed the threats to these species based 
upon the five factors described in section 4(a)(1) of the Act. Although 
these species occur on areas that are currently managed for 
conservation purposes, we have determined based on our analysis of the 
threats discussed below in the section ``Summary of Factors Affecting 
the Species,'' that these four invertebrate species are in danger of 
extinction throughout all or a significant portion of their respective 
ranges. Our analysis determined that these species are threatened by 
activities such as oil and gas production and development, groundwater 
pumping, and introduction of non-native species that are beyond the 
boundaries and/or the management protected areas where the species are 
found. Thus, the four invertebrates meet the definition of endangered 
species.
    (23) Comment: If these species are listed, is there a possible 
effect to the U.S. Bureau of Reclamation with respect to delivery of 
irrigation water?
    Our Response: Federal listing will require the Bureau of 
Reclamation (Reclamation) to consult with us on activities that have 
the potential to adversely affect the four invertebrates or designated 
critical habitat. None of Reclamation's current projects will be 
affected by the listing of the invertebrates and we are not aware of 
any future projects that may be affected by the listing. Delivery of 
irrigation water occurs via the Pecos River and we do not anticipate 
that listing these species will affect that activity.
    (24) Comment: Will the listing of these species impede the ability 
of the State of New Mexico to meet Pecos Compact River obligations?
    Our Response: No, the NMISC has been actively acquiring and leasing 
water rights to meet the State's delivery obligations to Texas as 
specified in the Pecos River Compact and pursuant to an Amended Decree 
entered by the U.S. Supreme Court. For example, between 1991 and 1999, 
$27.8 million was spent on the Pecos River water rights acquisition 
program. We do not anticipate that the listing of these species or the 
designation of critical habitat will alter the ability of the NMISC to 
meet Pecos River Compact delivery obligations. The amount of water 
being pumped from the Roswell Basin should not change; however, the use 
of water will change. For example, instead of being applied to fields, 
the water may be delivered to the Pecos River directly to meet Compact 
delivery obligations.
    (25) Comment: Will oil and gas exploration be further restricted in 
areas designated as critical habitat?
    Our Response: No, the Service does not anticipate that the 
designation of critical habitat will restrict oil and gas exploration. 
Section 7 consultation, when required, would analyze any impacts to the 
species and their designated critical habitat. The environmental 
assessment found that oil and gas projects with Federal involvement in 
the BLNWR and the surrounding area are already subject to stipulations 
for protecting groundwater (Service 2005). The Oil Conservation 
Division of the New Mexico Energy, Minerals, and Natural Resources 
Department regulates oil and gas well drilling and casing in part to 
prevent contamination of groundwater (19 NMAC 15.3).
    BLNWR is excluded from the designation of critical habitat for the 
four invertebrate species, and critical habitat would not result in 
additional section 7 consultations on federally supported oil and gas 
projects. Oil and gas well development in the vicinity of Diamond Y 
Springs Complex and East Sandia Spring occurs on private lands with no 
Federal involvement. Therefore, section 7 consultations on the effects 
to designated critical habitat would likely not occur for these 
projects. For this reason, we do not believe there would be any 
additional restrictions to oil and gas exploration activities.

Issue 3: National Environmental Policy Act (NEPA) Compliance and 
Economic Analysis

    (26) Comment: What has regulation or policy of Federal actions cost 
State and County governments before listing and critical habitat 
designation?
    Our Response: Since the proposed listing of the four invertebrates 
species, there have been specific conservation actions implemented that 
have taken into account the protection of the species. An estimated 
$366,000 to $494,000 in costs have been incurred by Federal and State 
agencies for the four invertebrates (Service 2005b). These

[[Page 46310]]

costs are related to developing the New Mexico State recovery plan and 
have included monitoring the four invertebrates' habitat, consultant 
fees, staff time devoted to developing the plan, administrative costs 
related to past conferences under section 7 of the Act, and associated 
monitoring of invertebrate habitat. We did not find that County 
governments have incurred any costs related to the conservation of 
these species.
    (27) Comment: Does the Service have an estimate of the costs 
required to recover the four invertebrates?
    Our Response: The costs of actions to recover the four 
invertebrates will be estimated during the development of a recovery 
plan.
    (28) Comment: The economic analysis should consider benefits of the 
critical habitat designation.
    Our Response: In the context of a critical habitat designation, the 
primary purpose of the rulemaking (i.e., the direct benefit) is to 
designate areas that have the features on which the species depend and 
that are in need of special management.
    The designation of critical habitat may result in two distinct 
categories of benefits to society: (1) Use benefits; and (2) non-use 
benefits. Use benefits are simply the social benefits that accrue from 
the physical use of a resource. Visiting critical habitat to see 
endangered species in their natural habitat would be a primary example. 
Non-use benefits, in contrast, represent welfare gains from ``just 
knowing'' that a particular listed species'' natural habitat is being 
specially managed for the survival and recovery of that species. Both 
use and non-use benefits may occur unaccompanied by any market 
transactions.
    A primary reason for conducting an economic analysis is to provide 
information regarding the economic impacts associated with a proposed 
critical habitat designation. Section 4(b)(2) of the Act requires the 
Secretary to designate critical habitat based on the best scientific 
data available after taking into consideration the economic impact, 
impact to national security, and any other relevant impact, of 
specifying any particular area as critical habitat. Economic impacts 
can be both positive and negative and by definition, are observable 
through market transactions.
    Where data are available, the economic analysis attempts to 
recognize and measure the net economic impact of the proposed 
designation. For example, if the fencing of a species' habitat to 
restrict motor vehicles results in an increase in the number of 
individuals visiting the site for wildlife viewing, then the analysis 
would recognize the potential for a positive economic impact and 
attempt to quantify the effect (e.g., impacts that would be associated 
with an increase in tourism spending by wildlife viewers). In this 
particular instance, however, the economic analysis did not identify 
estimates or measures of positive economic impacts that could offset 
some of the negative economic impacts analyzed earlier in this 
analysis.
    While the Act requires the Service to specifically consider the 
economic impact of a designation, it does not require the Service to 
explicitly consider any broader social benefits (or costs) that may be 
associated with the designation. In fact, the Service believes that 
this is by Congressional design, because the Act explicitly states that 
it is the Federal government's policy to conserve all threatened and 
endangered species and the ecosystems upon which they depend. While 
section 4(b)(2) of the Act gives the Secretary discretion to exclude 
certain areas from the final designation, she is authorized to do so 
only if an exclusion does not result in the extinction of the species. 
Thus, the Service believes that explicit consideration of broader 
social values for the species and its habitat, beyond economic impacts, 
is not necessary as Congress has already clarified the importance our 
society places on conserving all threatened and endangered species and 
their natural habitats upon which they depend. In terms of carrying out 
its responsibilities under section 4(b)(2) then, the Service need only 
consider whether the economic impacts (both positive and negative) are 
significant enough to merit exclusion of any particular area without 
causing the species to go extinct.
    (29) Comment: The economic analysis overstates costs by including 
past costs that occurred before the species was listed, costs that 
would result from the listing alone, and costs that derive from 
conservation efforts for other listed species. Similarly, the economic 
analysis includes costs of consultation with the Environmental 
Protection Agency (EPA) regarding Concentrated Animal Feeding 
Operations (CAFOs), which should be primarily associated with other 
listed species, and the listing of the four invertebrates, and not 
critical habitat designation.
    Our Response: This analysis identifies those economic activities 
believed to most likely threaten the four invertebrates and their 
habitat and, where possible, quantifies the economic impact to avoid, 
mitigate, or compensate for such threats within the boundaries of the 
critical habitat determination. The economic analysis considers past 
impacts associated with species conservation efforts that have been 
incurred since the proposed listing and critical habitat determination 
in 2002. The impact of these efforts is considered relevant to 
understanding the potential impact of the listing and critical habitat 
determination. Further, due to the difficulty in making a distinction 
between listing and critical habitat effects within critical habitat 
boundaries, this analysis considers all future conservation-related 
impacts to be coextensive with the designation.
    The consideration of co-extensive costs was mandated by the 10th 
Circuit Court of Appeals ruling in the New Mexico Cattle Growers 
Association case (248 F.3d at 1285), which directed us to consider all 
impacts, ``regardless of whether those impacts are attributable co-
extensively to other causes.'' As explained in the economic analysis, 
due to possible overlapping regulatory schemes and other reasons, there 
are also some elements of the analysis which may overstate some costs.
    Conversely, the 9th Circuit has recently ruled (``Gifford 
Pinchot,'' 378 F.3d at 1071) that the Service's regulations defining 
``adverse modification'' of critical habitat are invalid because they 
define adverse modification as affecting both survival and recovery of 
a species. The Court directed us to consider that adverse modification 
should be focused on impacts to recovery. While we have not yet 
proposed a new definition for public review and comment, changing the 
adverse modification definition to respond to the Court's direction may 
result in additional costs associated with critical habitat definitions 
(depending upon the outcome of the rulemaking).
    As described in section 1.2 of the economic analysis, coextensive 
effects may also include impacts associated with overlapping protective 
measures of other Federal, State, and local laws that aid habitat 
conservation in the areas proposed for designation, including 
protections for other listed species. These measures may be in part 
precipitated by the consideration of the presence of the species and 
impending critical habitat determination. Because the quantified 
habitat conservation efforts, regardless of their primary impetus, 
afford protection to the four invertebrates, they likely contribute to 
the efficacy of the critical habitat determination efforts. The impacts 
of these actions are therefore considered relevant for understanding 
the full effect of the proposed critical habitat determination. 
Enforcement actions

[[Page 46311]]

taken in response to violations of the Act, however, are not included.
    (30) Comment: The economic analysis inappropriately includes costs 
of delays in proposed drilling operations associated with industry 
appeals on applications for drilling permits. The oil and gas industry, 
however, is appealing environmental protections associated with their 
permits and burdening themselves. This should not be included as a cost 
of the critical habitat designation.
    Our Response: Industry appeals regarding drilling applications are 
a result of the implementation of environmental regulations, including 
the Act, that recommend additional species and habitat conservation 
efforts be undertaken with the drilling activity. The economic impacts 
of these delays are therefore considered relevant in understanding the 
impact of conservation efforts for the four invertebrates.
    (31) Comment: It is unclear from the economic analysis what 
additional protections from oil and gas activities may be provided by 
the Service for the four invertebrates as the economic analysis 
includes costs associated with the listing and with protections for 
other species, but no additional costs associated specifically with the 
critical habitat designation.
    Our Response: This analysis identifies the types of modifications 
to economic activities that may be undertaken to avoid, mitigate, or 
compensate for threats to the species and habitat. The draft economic 
analysis acknowledges the difficulty in distinguishing between listing 
and critical habitat effects and therefore considers all future 
conservation-related impacts to be coextensive with the critical 
habitat designation. Further, the relative level to which multiple 
considerations, including that of other species, contribute to the 
undertaking of a conservation effort is unclear. The impacts quantified 
in the analysis are assumed to be in some part precipitated by the 
critical habitat designation for the four invertebrates. Absent 
information on the specific increment by which critical habitat 
designation contributes to the undertaking of these efforts, the total 
impact of the effort is quantified, and not a fraction solely due to 
critical habitat designation.
    (32) Comment: The draft economic analysis relies on information 
provided by impacted industries to quantify the costs to those 
industries. These costs are inflated. For example, environmentally 
protective project modifications such as closed-loop systems can result 
in cost savings to the oil and gas industry. The draft economic 
analysis, however, only includes the costs to the industry of modifying 
projects to incorporate conservation measures for the species.
    Our Response: As the commenter notes, the potential for cost 
savings associated with implementing environmentally protective 
technologies, such as closed-loop systems, is acknowledged in the draft 
economic analysis on page 4-7. However, the level of benefit these 
modifications may generate is unclear. Additionally, application of 
closed-loop systems is not ubiquitous. As the industry indicates, it is 
not always the most beneficial operations alternative. The draft 
economic analysis therefore includes the full cost of this modification 
to oil and gas operations as a high-end estimate of the impact of 
conservation efforts.
    (33) Comment: The NMDGF's 2004 Biennial Review of threatened and 
endangered species in the State indicated that off-refuge land use 
practices within areas of the Roswell Artesian Basin (RAB), such as 
regional groundwater pumping for agriculture, municipal water supplies, 
and the oil and gas industries, threaten the invertebrate species. In 
contrast, a recent report prepared by the New Mexico Office of the 
State Engineer (OSE) provides the most recent information regarding the 
hydrology of the RAB. The report concludes that ``* * * an extended, 
extreme drought, and not groundwater depletion through human activity, 
would potentially threaten the future supply of water for the proposed 
critical habitat located within the BLNWR.''
    Our Response: Paragraph 77 and section 4.2.2 of the draft economic 
analysis state that no hydrologic models currently exist to determine 
the impact of groundwater pumping of the RAB on the springs at the 
BLNWR. The revised economic analysis acknowledges recent information 
resulting from the OSE report. As the draft economic analysis does not 
quantify impacts of critical habitat designation to groundwater 
pumping; however, the quantitative results of this analysis are 
unchanged as a result of this comment.

Summary of Changes From the Proposed Rule

    Based upon our review of the public comments, the economic 
analysis, environmental assessment, issues addressed at the public 
hearing, and any new relevant information that may have become 
available since the publication of the proposal, we reevaluated our 
proposed listing and critical habitat designation and made changes as 
appropriate. Other than minor clarifications and incorporation of 
additional information on the species' biology, this final rule differs 
from the proposal by:
    (1) The exclusion of critical habitat on BLNWR because special 
management considerations are currently provided to the four 
invertebrates through current BLNWR management; and
    (2) Changes to the primary constituent elements of critical habitat 
for the Pecos assiminea.

Summary of Factors Affecting the Species

    Section 4 of the Act and implementing regulations (50 CFR 424) set 
forth the procedures for adding species to the Federal lists. A species 
may be determined to be threatened or endangered due to one or more of 
the five factors described in section 4(a)(1) of the Act. These factors 
and their application to the Roswell springsnail, Koster's springsnail, 
Pecos assiminea, and Noel's amphipod are as follows.
    A. The present or threatened destruction, modification, or 
curtailment of its habitat or range.
    Several biological traits of a population have been identified as 
putting a species at risk of extinction (McKinney 1997; O'Grady 2004). 
Some of these characteristics include having a localized range, limited 
mobility, and fragmented habitat (McKinney 1997; O'Grady 2004). The 
four invertebrates have all of these characteristics. Having a small, 
localized range means that any perturbation, either natural (e.g., 
drought) or anthropogenic (e.g., water contamination) can eliminate 
many or all of the existing populations. Having a high number of 
individuals at a site provides no protection against extinction. Noel 
(1954) noted that the amphipod in Lander Spring was the most abundant 
animal present. It was extirpated from that site when the spring dried 
up (Cole 1985). The range reduction trend in these snail species (e.g., 
by extirpation of once widely distributed but localized populations) is 
supported by the Pleistocene fossil record in conjunction with re-
inventory of known site occurrences in which no individuals were 
detected (Noel 1954; Taylor 1987; Mehlhop 1992, 1993; NMDGF 1999). 
Fossil records indicate that at least one or more of these snail 
species were historically found at Berrendo Creek, North Spring, and 
South Spring Rivers, and along the Pecos River (NMDGF 1999). This 
evidence suggests an apparent historical decline in the numbers, range, 
and distribution of these species.

[[Page 46312]]

    Limited mobility restricts the ability of the invertebrates to find 
and disperse to other suitable habitats or to move out of habitat that 
becomes unsuitable. Consequently, their range remains restricted and 
they are unable to avoid contaminants or other unfavorable changes to 
their habitat. Fragmented (unconnected) habitat restricts gene flow 
among populations and limits the ability of the invertebrates to 
recolonize habitats that have been disturbed but then recover. For 
example, three springs once contributed to Berrendo Creek in the 
Roswell Basin. If the population of springsnails in one of the springs 
was eliminated because of a toxic spill, after the habitat had 
recovered, the spring could have been colonized naturally by dispersal 
of animals from the other springs. In the currently fragmented 
habitats, dispersal is highly unlikely and if a population is 
extirpated the habitat probably will not be recolonized, further 
restricting the range.
    In addition to the characteristics listed above that may put 
species at greater risk of extinction, habitat loss, introduced 
species, and habitat degradation can also lead to extinction (Meffe et 
al. 1994; Frankham et al. 2002). Each of these topics is discussed in 
detail. Curtailment of range and habitat of the four invertebrates has 
occurred primarily through the loss of suitable spring habitat. These 
species were most likely much more widely distributed throughout the 
Pecos River Basin during the wetter climatic period of the Pleistocene. 
As the climate became warmer and drier, the invertebrates were 
restricted to the remaining free-flowing springs. Fossil records 
indicate that two of the snail species were found at Berrendo Creek and 
along the Pecos River (Taylor 1987).
    In addition, in the late 1800s, flow at North Spring, South Spring, 
and Berrendo Creek was 85 cubic feet per second (cfs) (2.4 cubic meters 
per second [cms], 60 cfs (1.7 cms), and 66 (1.9 cms) cfs, respectively 
(Fiedler and Nye 1933). These systems each provided abundant habitat 
for the invertebrates. Lander Spring, a tributary spring of South 
Spring, harbored Noel's amphipod (Noel 1954). The historic connection 
of these spring systems to the Pecos River most likely facilitated 
dispersal of the invertebrates throughout the basin downstream of this 
area.
    In the 1880s, irrigated agriculture in the Roswell and Artesia 
Basins was limited to a few small farms (Fielder and Nye 1933). By the 
end of 1905, 485 artesian wells had been drilled and by 1927, 1,424 
wells were pumping water (Fiedler and Nye 1933). One well, drilled for 
the Oasis Cotton Company, is estimated to have produced 9,000 gallons/
minute (20 cfs) (Fiedler and Nye 1933, Jones and Balleau 1996). As a 
result of extensive groundwater pumping, the artesian head in the basin 
declined (Fiedler and Nye 1933). The amount of decline depended on 
location within the basin and ranged from 32 to 204 feet (9.7 to 62.2 
meters) from original levels by 1927, and led to a decrease in area 
within the basin that had artesian flow (Fiedler and Nye 1933). 
Groundwater depletion continued until the mid-1970s, when it reached 
its maximum (McCord et al. 2005).
    By 1926, South Spring was dry (Jones and Balleau 1996). Berrendo 
Spring still produced 8.3 cfs, about 12 percent of the original 1880s 
flow (Jones and Balleau 1996). Today, Berrendo Well produces less than 
1 cfs (McCord et al. 2005). Lander Spring went dry in the late 1950s or 
early 1960s (Cole 1981), extirpating the population of Noel's amphipod, 
which in the early 1950s had been described by Noel (1954) as the most 
abundant animal in the spring. Discharge at North Spring is unknown. 
Jones and Balleau (1996) list its flow as 0 in 1926, but Cole (1981) 
described 3 small separate brooks that entered a pond on a private golf 
course in 1967. Surveys in 1995 at the site indicated that Roswell 
springsnail and Koster's springsnail were still present at the location 
(Noel's amphipod once occupied the site). Surveys in 2004 found none of 
the species, most likely due to habitat modification from pond 
enlargement (NMDGF 2005a). Surface flow at BLNWR was also diminished by 
artesian pumping. Springs adjacent to Salt Creek no longer flow, and 
surface flow from the Middle Area of BLNWR (sum of flow in upper Bitter 
Creek and Middle Area springs) was 15 cfs (0.4 cms)