Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Roswell Springsnail, Koster's Springsnail, Noel's Amphipod, and Pecos Assiminea, 33036-33064 [2011-13227]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 109 (Tuesday, June 7, 2011)]
[Rules and Regulations]
[Pages 33036-33064]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-13227]



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Vol. 76

Tuesday,

No. 109

June 7, 2011

Part II





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; Designation of Critical 
Habitat for Roswell Springsnail, Koster's Springsnail, Noel's Amphipod, 
and Pecos Assiminea; Final Rule

Federal Register / Vol. 76 , No. 109 / Tuesday, June 7, 2011 / Rules 
and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2009-0014; 92210-1117-0000-B4]
RIN 1018-AW50


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for Roswell Springsnail, Koster's Springsnail, Noel's 
Amphipod, and Pecos Assiminea

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service, designate critical 
habitat for the Pecos assiminea (Assiminea pecos), Roswell springsnail 
(Pyrgulopsis roswellensis), Koster's springsnail (Juturnia kosteri), 
and Noel's amphipod (Gammarus desperatus), under the Endangered Species 
Act of 1973, as amended. In total, we are designating as critical 
habitat approximately 521.3 acres (211.0 hectares) for the four species 
of aquatic invertebrates. The critical habitat is located in Chaves 
County, New Mexico, and Pecos and Reeves Counties, Texas.

DATES: This rule becomes effective on July 7, 2011.

ADDRESSES: This final rule and the associated final economic analysis 
and final environmental assessment are available on the Internet at 
https://www.regulations.gov or https://www.fws.gov/southwest/es/NewMexico/. Comments and materials received, as well as supporting 
documentation used in preparing this final rule, are 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 Rd, NE, Albuquerque, NM 87113; telephone 505-346-
2525; facsimile 505-346-2542.

FOR FURTHER INFORMATION CONTACT: Wally ``J'' Murphy, Field Supervisor, 
U.S. Fish and Wildlife Service, New Mexico Ecological Services Field 
Office, 2105 Osuna Rd, NE, Albuquerque, NM 87113; telephone 505-761-
4781; facsimile 505-246-2542. If you use a telecommunications device 
for the deaf (TDD), call the Federal Information Relay Service (FIRS) 
at 800-877-8339.

SUPPLEMENTARY INFORMATION:  It is our intent to discuss in this final 
rule only those topics directly relevant to the development and 
designation of critical habitat for the Roswell springsnail 
(Pyrgulopsis roswellensis), Koster's springsnail (Juturnia kosteri), 
Noel's amphipod (Gammarus desperatus), and Pecos assiminea (Assiminea 
pecos) (four invertebrates). For more information on the biology and 
ecology of the four invertebrates, refer to the final listing rule 
published in the Federal Register on August 9, 2005 (70 FR 46304). For 
information on the four invertebrates' critical habitat, refer to the 
proposed rule to designate critical habitat for the four invertebrates, 
published in the Federal Register on June 22, 2010 (75 FR 35375), and 
February 17, 2011 (76 FR 9297).

Previous Federal Actions

    On February 12, 2002, we proposed listing the Roswell springsnail, 
Koster's springsnail, Noel's amphipod, and Pecos assiminea as 
endangered with critical habitat (67 FR 6459) under the Endangered 
Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.). 
Proposed critical habitat for the four species included portions of 
Bitter Lake National Wildlife Refuge (Refuge) in New Mexico, as well as 
two sites in Texas for the Pecos assiminea. On May 31, 2002, and again 
on May 4, 2005, we reopened the comment period on our February 12, 
2002, proposed listing of the four invertebrates with critical habitat 
(67 FR 38059 and 70 FR 23083, respectively).
    On August 9, 2005, we listed Roswell springsnail, Koster's 
springsnail, Noel's amphipod, and Pecos assiminea as endangered under 
the Act (70 FR 46304). In that rule, we also designated critical 
habitat for Pecos assiminea at Diamond Y Springs Complex in Pecos 
County, Texas, and at East Sandia Springs in Reeves County, Texas. We 
excluded proposed areas on the Refuge from the final critical habitat 
designation because special management for the four invertebrates was 
already occurring there. As a result, only the Pecos assiminea had 
critical habitat designated for two areas in Texas, and no critical 
habitat was designated for the other three species.
    On March 12, 2009, in response to a complaint filed by Forest 
Guardians (now WildEarth Guardians) challenging the exclusion of the 
Refuge from the final critical habitat designation for the four 
invertebrate species, we published an announcement reopening a 60-day 
comment period on the proposed designation of lands of the Bitter Lake 
National Wildlife Refuge as critical habitat for the four invertebrates 
(74 FR 10701).
    On June 22, 2010, we published a proposed rule to revise critical 
habitat for the Pecos assiminea and propose new critical habitat for 
Roswell springsnail, Koster's springsnail, and Noel's amphipod (75 FR 
35375). The comment period was open for 60 days and closed on August 
23, 2010. Information we received during that comment period led to our 
consideration of a new area for critical habitat for the Noel's 
amphipod along the Rio Hondo on the South Tract of the Refuge and, 
therefore, led to our publication of an additional document on February 
17, 2011 (76 FR 9297), to accept public comment on the proposed 
designation of this additional area.

Summary of Comments and Recommendations

    We requested written comments from the public on the proposed 
designation of critical habitat for the four invertebrates during the 
comment periods held from March 12 to May 11, 2009; June 22 to August 
23, 2010; and February 17 to March 21, 2011. We did not receive any 
requests for a public hearing, and none was held. We also contacted 
appropriate Federal, State, and local agencies; scientific 
organizations; and other interested parties and invited them to comment 
on the proposed rule, draft economic analysis, and draft environmental 
assessment during the last two comment periods.
    During the comment periods, we received six comment letters 
directly addressing the proposed critical habitat designation. All 
substantive information provided during comment periods has either been 
incorporated directly into this final determination as appropriate or 
addressed below.

Peer Review

    In accordance with our peer review policy published on July 1, 1994 
(59 FR 34270), we solicited expert opinions from three knowledgeable 
individuals with scientific expertise that included familiarity with 
the species, the geographic region in which the species occur, and 
conservation biology principles. We received responses from two of the 
peer reviewers.
    We reviewed all comments received from the peer reviewers for 
substantive issues and new information regarding critical habitat for 
the four invertebrates. The peer reviewers generally concurred with our 
methods and conclusions and provided additional information, 
clarifications, and suggestions to improve the final critical habitat 
rule. Peer reviewer comments are addressed in the following summary and 
incorporated into the final rule as appropriate.

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Peer Reviewer Comments

    (1) Comment: Both peer reviewers and the State of New Mexico 
recommended the habitat supporting the Rio Hondo population of Noel's 
amphipod on the South Tract of the Refuge be included in this critical 
habitat designation.
    Our response: We agree that the Rio Hondo population of Noel's 
amphipod should be included in this designation of critical habitat, 
and we published an additional document to request public comments on 
the proposed designation of the additional area on February 17, 2011 
(76 FR 9297). We have included this area in this final critical habitat 
designation.
    (2) Comment: One peer reviewer and the State of New Mexico 
requested we clarify the language discussing the number of locations of 
Pecos assiminea that occur on the Refuge, which stated disparate 
numbers of populations.
    Our response: We have revised the language accordingly in this 
final critical habitat designation.
    (3) Comment: One peer reviewer suggested we designate additional 
areas of Hunter Marsh on the Refuge that may likely contain additional 
habitat occupied by the four invertebrates.
    Our response: We considered all areas of Hunter Marsh for possible 
inclusion as critical habitat. In doing so, we relied on species 
experts and Refuge staff to identify those areas occupied by any of the 
four invertebrates at the time of listing that contain the physical or 
biological features essential to the conservation of the species and 
which may require special management considerations or protection. 
Using mapping techniques and field visits, we designated all areas 
within this tract on the Refuge that meet the criteria for critical 
habitat. For areas not occupied by any of the four invertebrates at the 
time they were listed, we found none that would meet the criteria to be 
essential for the four invertebrates' conservation, and none of the 
four invertebrates is likely to become established in other areas.
    (4) Comment: One peer reviewer and the State of New Mexico noted 
that the Pecos assiminea proposed critical habitat map does not show 
any of the property owned by the City of Roswell (City) as being 
proposed for critical habitat.
    Our response: In the proposal, we incorrectly identified the Refuge 
boundary. The revised map shows the correct boundary, accurately 
displaying portions of Units 2a and 2b as City property.

Comments From States

    Section 4(i) of the Act states, ``the Secretary shall submit to the 
State agency a written justification for his failure to adopt 
regulations consistent with the agency's comments or petition.'' We 
received two comment letters from the State of New Mexico. The comments 
in the first letter are addressed above (see (1), (2), and (4) under 
Peer Reviewer Comments). The second letter specifically addressed our 
February 17, 2011 (76 FR 9297), proposed rule, stating that the New 
Mexico Department of Game and Fish (NMDGF) supports the critical 
habitat designation.

Public Comments

    (5) Comment: One commenter suggested we include additional areas 
surrounding depleted springs and ponds as critical habitat.
    Our response: Much of the historic habitat for these four 
invertebrates has been degraded to such a degree that it no longer 
contains the physical and biological features necessary for 
conservation of these species. Only areas meeting the criteria for 
critical habitat for the four invertebrates are designated as critical 
habitat in this rule, as well as surrounding areas contiguous with 
occupied habitat that may be inhabited in the future. Because the 
depleted springs and ponds mentioned by the commenter are dewatered due 
to groundwater loss in the area, it is not likely they could be 
rehabilitated in the future to restore the necessary habitat features 
for the four invertebrates. Therefore, these areas are unlikely to 
contribute to the recovery of the species, are not considered essential 
to their conservation, and are not included in this critical habitat 
designation.
    (6) Comment: One commenter recommended limiting designation of 
critical habitat to areas of the Refuge where the four invertebrates 
can occur.
    Our response: Updated geographic information system (GIS) 
techniques have allowed us to more closely map the wetlands, springs, 
and seeps on the Refuge in which the four invertebrates can occur; 
therefore, our designation is refined from the 2002 proposal to 
designate critical habitat for the four invertebrates (February 12, 
2002; 67 FR 6459) and no longer includes uplands or other Refuge lands 
that do not contain the essential physical and biological features of 
critical habitat for these four invertebrates.

Summary of Changes From the Proposed Rule

    Since the publication of the June 22, 2010, proposed rule to revise 
critical habitat for the Pecos assiminea and propose new critical 
habitat for Roswell springsnail, Koster's springsnail, and Noel's 
amphipod (75 FR 35375), we have made the following changes:
    (1) Because the Pecos assiminea occupies different habitats than 
the Roswell springsnail, Koster's springsnail, and Noel's amphipod, we 
created separate critical habitat units for the Pecos assiminea on the 
Refuge.
    (2) Due to the discovery of a population of Noel's amphipod along 
the Rio Hondo on the South Tract of the Refuge, we proposed an 
additional critical habitat area on February 17, 2011 (76 FR 9297). 
This area is included as critical habitat in this final rule.
    (3) Because of the addition of new units for the Pecos assiminea 
and Noel's amphipod, the unit numbers have changed from those in the 
proposed rule.
    (4) Due to a mapping error, the total amount of critical habitat is 
0.5 acres (ac) (0.2 hectares (ha)) more than was proposed. No 
additional critical habitat has been designated in this rule, as the 
error was purely mathematical.

Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species and
    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance,

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propagation, live trapping, and transplantation, and, in the 
extraordinary case where population pressures within a given ecosystem 
cannot be otherwise relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that Federal agencies ensure, in consultation 
with the U.S. Fish and Wildlife Service (Service), that any action they 
authorize, fund, or carry out is not likely to result in the 
destruction or adverse modification of critical habitat. The 
designation of critical habitat does not affect land ownership or 
establish a refuge, wilderness, reserve, preserve, or other 
conservation area. Such designation does not allow the government or 
public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by 
non-Federal landowners. Where a landowner seeks or requests Federal 
agency funding or authorization for an action that may affect a listed 
species or critical habitat, the consultation requirements of section 
7(a)(2) of the Act would apply, but even in the event of a destruction 
or adverse modification finding, the obligation of the Federal action 
agency and the landowner is not to restore or recover the species, but 
to implement reasonable and prudent alternatives to avoid destruction 
or adverse modification of critical habitat.
    For inclusion in a critical habitat designation, the habitat within 
the geographical area occupied by the species at the time it was listed 
must contain physical and biological features which are essential to 
the conservation of the species and which may require special 
management considerations or protection. Critical habitat designations 
identify, to the extent known using the best scientific and commercial 
data available, those physical and biological features that are 
essential to the conservation of the species (such as space, food, 
cover, and protected habitat), focusing on the principal biological or 
physical constituent elements (primary constituent elements) within an 
area that are essential to the conservation of the species (such as 
roost sites, nesting grounds, seasonal wetlands, water quality, tide, 
soil type). Primary constituent elements are the elements of physical 
and biological features that provide for a species' life history 
processes and are essential to the conservation of the species.
    Under the Act, we can designate critical habitat in areas outside 
the geographical area occupied by the species at the time it is listed, 
upon a determination that such areas are essential for the conservation 
of the species. We designate critical habitat in areas outside the 
geographical area occupied by a species only when a designation limited 
to its range would be inadequate to ensure the conservation of the 
species. When the best available scientific data do not demonstrate 
that the conservation needs of the species require such additional 
areas, we will not designate critical habitat in areas outside the 
geographical area occupied by the species. An area currently occupied 
by the species but that was not occupied at the time of listing may, 
however, be essential to the conservation of the species and may be 
included in the critical habitat designation.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards Under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658)), and our associated Information Quality 
Guidelines, provide criteria, establish procedures, and provide 
guidance to ensure that our decisions are based on the best scientific 
data available. They require our biologists, to the extent consistent 
with the Act and with the use of the best scientific data available, to 
use primary and original sources of information as the basis for 
recommendations to designate critical habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources may include the recovery plan for the 
species, articles in peer-reviewed journals, conservation plans 
developed by States and counties, scientific status surveys and 
studies, biological assessments, or other unpublished materials and 
expert opinion or personal knowledge.
    We recognize that critical habitat designated at a particular point 
in time may not include all of the habitat areas that we may later 
determine are necessary for the recovery of the species. For these 
reasons, a critical habitat designation does not signal that habitat 
outside the designated area is unimportant or may not be required for 
recovery of the species. Areas that are important to the conservation 
of the species, both inside and outside the critical habitat 
designation, will continue to be subject to: (1) Conservation actions 
implemented under section 7(a)(1) of the Act, (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to insure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species, and (3) the prohibitions of section 9 of the Act if actions 
occurring in these areas may affect the species. Federally funded or 
permitted projects affecting listed species outside their designated 
critical habitat areas may still result in jeopardy findings in some 
cases. These protections and conservation tools will continue to 
contribute to recovery of this species. Similarly, critical habitat 
designations made on the basis of the best available information at the 
time of designation will not control the direction and substance of 
future recovery plans, habitat conservation plans (HCPs), or other 
species conservation planning efforts, if new information available at 
the time of these planning efforts calls for a different outcome.

Physical and Biological Features

    In accordance with sections 3(5)(A)(i) and 4(b)(1)(A) of the Act 
and the regulations at 50 CFR 424.12, in determining which areas within 
the geographical area occupied at the time of listing to designate as 
critical habitat, we consider the physical and biological features 
essential to the conservation of the species that may require special 
management considerations or protection. These include, but are not 
limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historic, geographical, and ecological 
distributions of a species.
    We derive the specific physical and biological features required 
for the four invertebrates from studies of these species' habitat, 
ecology, and life history as described in the Critical Habitat section 
of the proposed rule to designate critical habitat published in the 
Federal Register on June 22, 2010 (75 FR 35375) and in the information 
presented below. Additional information can be found in the final 
listing rule published in the

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Federal Register on August 9, 2005 (70 FR 46304). We have determined 
that the following physical and biological features are required by the 
four invertebrates.
Space for Individual and Population Growth and for Normal Behavior
Roswell Springsnail, Koster's Springsnail, Noel's Amphipod
    The aquatic environment provides foraging and sheltering habitat 
for Roswell springsnail, Koster's springsnail, and Noel's amphipod, as 
well as habitat structure necessary for reproduction and survival of 
offspring. These invertebrates are completely aquatic and require 
perennial, flowing water for all of their life stages. The springsnails 
can survive in seepage areas, as long as flows are perennial and within 
the species' physiological tolerance limit; pool-like habitat is less 
suitable for these species, which prefer flowing water. They inhabit 
springs and spring-fed wetland systems with variable water temperatures 
(50-68 degrees Fahrenheit ([deg]F)) (10-20 degrees Celsius ([deg]C)). 
In general, the springsnails inhabit slow to moderate water velocities 
over compact substrate (material on the bottom of the stream) ranging 
from deep organic silts to gypsum sands and gravel (NMDGF 2005, pp. 13, 
16). Habitat of Koster's springsnail consists of soft substrates of 
springs and seeps (Taylor 1987, p. 43). Roswell springsnail, on the 
other hand, was found to be most abundant on hard, gypsum substrate 
(NMDGF 2005, p. 16), which may make the species more susceptible to 
sedimentation. Noel's amphipod is found beneath stones and in aquatic 
vegetation (Cole 1988, p. 5; Smith 2001, pp. 572-574). The addition of 
stones, which increased current velocity, appeared to improve habitat 
for Noel's amphipod along the Unit 6 spring-ditch on the Refuge (Lang 
2002, p. 2).
    The two springsnails and Noel's amphipod are sensitive to water 
contamination. Amphipods generally do not tolerate habitat desiccation 
(drying), standing water, sedimentation, or other adverse environmental 
conditions; they are very sensitive to habitat degradation (NMDGF 1999, 
p. B3; Smith 2001, p. 575; NMDGF 2005, p. 15). Further, Taylor (1985, 
p. 15) concluded that an unidentified groundwater pollutant was 
responsible for reduction in abundance of springsnail species in the 
headspring and outflow of Diamond Y Spring, in Pecos County, Texas.
Pecos Assiminea
    The Pecos assiminea requires saturated, moist soil at stream or 
spring-run margins and is found in wet mud or beneath mats of 
vegetation, usually within 1 inch (in) (2 to 3 centimeters (cm)) of 
flowing water. Spring complexes that contain flowing water create 
saturated soils that provide the specific habitat needed for population 
growth, sheltering, and normal behavior of the species. Although this 
snail seldom occurs immersed in water, the species cannot withstand 
permanent drying of springs or spring complexes. Consequently, wetland 
plant species are required to provide leaf litter (dead leaf material), 
shade, and appropriate microhabitat. Plant species such as Scirpus 
americanus (American three-square), Eleocharis spp. (spike rush), 
Distichlis spicata (inland saltgrass), and Juncus spp. (rushes) provide 
the appropriate cover and shelter required by Pecos assiminea (NMDGF 
2005, p. 13).
Food
    Invertebrates in small spring ecosystems depend on food from two 
sources: that which grows in or on the substrate (aquatic and attached 
plants and algae) and that which falls or is blown into the system 
(primarily leaves). Leaves from nonnative plants that fall into the 
water are often less suitable food sources for invertebrates because of 
either their resins or their physical structure (Bailey et al. 2001, p. 
445). Water is also the medium necessary to provide the algae, detritus 
(dead or partially decayed plant materials or animals), bacteria, and 
submergent vegetation (vegetation submerged in water) on which the four 
species depend as a food resource, although submergent vegetation is 
less important for the Pecos assiminea because it inhabits the wet 
soils just above the water's edge.
Roswell Springsnail and Koster's Springsnail
    The springsnails feed on algae, bacteria, and decaying organic 
material (NMDGF 2005, p. 14). They will also incidentally ingest small 
invertebrates while grazing on algae and detritus. Submergent 
vegetation contributes the necessary nutrients, detritus, and bacteria 
on which these species forage. Resource abundance and productivity 
appears to be an important factor in regulating population size (NMDGF 
2005, p. 16).
Noel's Amphipod
    Amphipods are omnivorous, feeding on algae, submergent vegetation, 
and decaying organic matter (Holsinger 1976, p. 28; Pennak 1989, p. 
476). Noel's amphipod is often found in beds of submergent aquatic 
plants, indicating that they probably feed on a surface film of algae, 
diatoms (single-celled algae with high silica content), bacteria, and 
fungi (Smith 2001, p. 575; NMDGF 2005, p. 14). Young amphipods depend 
on microbial foods, such as algae and bacteria, associated with aquatic 
plants (Covich and Thorp 1991, p. 677). Cannibalism may occur at high 
densities when food becomes limiting (Smith 2001, p. 575; NMDGF 2005, 
p. 15).
Pecos Assiminea
    The Pecos assiminea has a file-like radula (a ribbon of teeth) 
situated behind the mouth that it uses to graze or scrape food from the 
foraging surface. Saturated soils and wetland vegetation adjacent to 
spring complexes contribute to the necessary components to support the 
algae, detritus, and bacteria on which this species forages.
Primary Constituent Elements
    Under the Act and its implementing regulations, we are required to 
identify the physical and biological features essential to the 
conservation of the Roswell springsnail, Koster's springsnail, Noel's 
amphipod, and Pecos assiminea in areas occupied at the time of listing, 
focusing on the features' primary constituent elements. We consider 
primary constituent elements to be the elements of physical and 
biological features that provide for a species' life-history processes 
and are essential to the conservation of the species.

Primary Constituent Elements for Roswell Springsnail and Koster's 
Springsnail

    Based on the above needs and our current knowledge of the life 
history, biology, and ecology of the species and the habitat 
requirements for sustaining the essential life history functions of the 
species, we have determined that the primary constituent element 
essential to the conservation of Roswell springsnail and Koster's 
springsnail is springs and spring-fed wetland systems that:
    (1) Have permanent, flowing water with no or no more than low 
levels of pollutants;
    (2) Have slow to moderate water velocities;
    (3) Have substrates ranging from deep organic silts to limestone 
cobble and gypsum;
    (4) Have stable water levels with natural diurnal (daily) and 
seasonal variations;

[[Page 33040]]

    (5) Consist of fresh to moderately saline water;
    (6) Vary in temperature between 50-68 [deg]F (10-20 [deg]C) with 
natural seasonal and diurnal variations slightly above and below that 
range; and
    (7) Provide abundant food, consisting of:
    (a) Algae, bacteria, and decaying organic material; and
    (b) Submergent vegetation that contributes the necessary nutrients, 
detritus, and bacteria on which these species forage.

Primary Constituent Elements for Noel's Amphipod

    Based on the above needs and our current knowledge of the life 
history, biology, and ecology of the species and the habitat 
requirements for sustaining the essential life history functions of the 
species, we have determined that the primary constituent element 
essential to the conservation of Noel's amphipod is springs and spring-
fed wetland systems that:
    (1) Have permanent, flowing water with no or no more than low 
levels of pollutants;
    (2) Have slow to moderate water velocities;
    (3) Have substrates including limestone cobble and aquatic 
vegetation;
    (4) Have stable water levels with natural diurnal (daily) and 
seasonal variations;
    (5) Consist of fresh to moderately saline water;
    (6) Have minimal sedimentation;
    (7) Vary in temperature between 50-68 [deg]F (10-20 [deg]C) with 
natural seasonal and diurnal variations slightly above and below that 
range; and
    (8) Provide abundant food, consisting of:
    (a) Submergent vegetation and decaying organic matter;
    (b) A surface film of algae, diatoms, bacteria, and fungi; and
    (c) Microbial foods, such as algae and bacteria, associated with 
aquatic plants, algae, bacteria, and decaying organic material.

Primary Constituent Elements for Pecos Assiminea

    Based on the above needs and our current knowledge of the life 
history, biology, and ecology of the species and the habitat 
requirements for sustaining the essential life history functions of the 
species, we have determined that the primary constituent element 
essential to the conservation of Pecos assiminea is moist or saturated 
soil at stream or spring run margins:
    (1) That consists of wet mud or occurs beneath mats of vegetation;
    (2) That is within 1 in (2 to 3 cm) of flowing water;
    (3) That has native wetland plant species, such as salt grass or 
sedges, that provide leaf litter, shade, cover, and appropriate 
microhabitat;
    (4) That contains wetland vegetation adjacent to spring complexes 
that supports the algae, detritus, and bacteria needed for foraging; 
and
    (5) That has adjacent spring complexes with:
    (a) Permanent, flowing, fresh to moderately saline water with no or 
no more than low levels of pollutants; and
    (b) Stable water levels with natural diurnal and seasonal 
variations.
    With this designation of critical habitat, we intend to identify 
the physical and biological features essential to the conservation of 
the species, through the identification of the primary constituent 
elements sufficient to support the life-history processes of the 
species. All units designated as critical habitat are currently 
occupied by at least one of the four invertebrates and contain the 
primary constituent elements sufficient to support the life history 
needs of the species.

Special Management Considerations or Protection

    When designating critical habitat, we assess whether the specific 
areas within the geographical area occupied by the species at the time 
of listing contain features that are essential to the conservation of 
the species and that may require special management considerations or 
protection. As stated in the final listing rule (70 FR 46304; August 9, 
2005), threats to the four invertebrates include reducing or 
eliminating water in suitable or occupied habitat through drought or 
pumping; introducing pollutants to levels unsuitable for the species 
from urban areas, agriculture, release of chemicals, and oil and gas 
operations; fires that reduce or eliminate available habitat; and 
introducing nonnative species into the invertebrates' inhabited spring 
systems such that suitable habitat is reduced or eliminated. Each of 
these threats is discussed below.
Water Quantity
    These four invertebrate species depend on water for survival. 
Therefore, the loss or alteration of spring habitat continues to be the 
main threat to the four invertebrates. The scattered distribution of 
springs makes them aquatic islands of unique habitat in an arid-land 
matrix (Myers and Resh 1999, p. 815).
    Members of the snail family Hydrobiidae (including Roswell and 
Koster's springsnails) are susceptible to extirpation or extinction 
because they often occur in isolated desert springs (Hershler 1989, p. 
294; Hershler and Pratt 1990, p. 291; Hershler 1994, p. 1; Lydeard et 
al. 2004, p. 326). There is evidence these habitats have been 
historically reduced or eliminated by aquifer depletion (Jones and 
Balleau 1996, p. 4). The lowering of water tables through aquifer 
withdrawals for irrigation and municipal use has degraded desert spring 
habitats. At least two historical sites for the invertebrates (South 
Spring, Lander Spring) are currently dry due to aquifer depletion (Cole 
1981, p. 27; Jones and Balleau 1996, p. 5), and Berrendo Spring, 
historical habitat for the Roswell springsnail, is currently at 12 
percent of the original 1880s flow (Jones and Balleau 1996, p. 13). 
However, during the mid-1970s, when groundwater pumping was at its 
highest rate and the area was experiencing extreme drought (McCord et 
al. 2005, p. 6), the springs currently inhabited by the species 
continued to flow. This suggests these springs and seeps may be 
somewhat resilient to reduced water levels, although climate change may 
test that resiliency.
    Models suggest climate change may cause the southwestern United 
States to experience the greatest temperature increase of any area in 
the lower 48 States (IPCC 2007, p. 15). There is also high confidence 
that many semi-arid areas like the western United States will suffer a 
decrease in water resources due to climate change (IPCC 2007, p. 16), 
as a result of less annual mean precipitation and reduced length of 
snow season and snow depth (Christensen et al. 2007, p. 850). These 
predictions underscore the importance of special management to maintain 
aquifer levels to ensure survival of the four invertebrates.
    The primary threat to Pecos assiminea in Texas is the potential 
failure of spring flow due to excessive groundwater pumping or drought 
or both, which would result in total habitat loss for the species. 
Diamond Y Spring is the last major spring still flowing in Pecos 
County, Texas (Veni 1991, p. 2). Pumping of the regional aquifer system 
for agricultural production of crops has resulted in the drying of most 
other springs in this region (Brune 1981, p. 356). Other springs that 
have already failed include Comanche Springs, which was once a large 
spring in Fort Stockton, Texas, about 8 miles (mi) (12.9 kilometers 
(km)) from Diamond Y Spring. Comanche Springs flowed at more than 142 
cubic feet per second (cfs) (4.0 cubic meters per second (cms))

[[Page 33041]]

(Scudday 1977, p. 515; Brune 1981, p. 358) and undoubtedly provided 
habitat for rare species of fish and invertebrates, including 
springsnails. The spring ceased flowing by 1962 (Brune 1981, p. 358), 
except for brief periods (Small and Ozuna 1993, p. 26). Leon Springs, 
located upstream of Diamond Y Spring in the Leon Creek watershed, was 
measured at 18 cfs (0.5 cms) in the 1930s and was also known to contain 
rare fish, but ceased flowing in the 1950s following significant 
irrigation pumping (Brune 1981, p. 359). There have been no continuous 
records of spring flow discharge at Diamond Y Spring by which to 
determine trends in spring flow.
    East Sandia Spring discharges at an elevation of 3,205 feet (ft) 
(977 meters (m)) from alluvial sand and gravel (Schuster 1997, pp. 92-
93). Brune (1981, pp. 385-386) noted that flows from East Sandia Spring 
were declining. East Sandia Spring may be very susceptible to over-
pumping in the area of the local aquifer that supports the spring. 
Measured discharges in 1995 and 1996 ranged from 0.45 to 4.07 cfs 
(0.013 to 0.11 cms) (Schuster 1997, p. 94). The small outflow channel 
from East Sandia Spring has not been significantly modified, and water 
flows into an irrigation system approximately 328 to 656 ft (100 to 200 
m) after surfacing.
    In summary, special management considerations are needed to protect 
the habitats of the four invertebrates from the loss or alteration of 
spring habitat as a result of drought or pumping.
Water Contamination
    Water contamination, particularly from oil and gas operations, is a 
significant threat for these four invertebrates. In order to assess the 
potential for contamination, a study was completed in September 1999 to 
delineate the area that serves as sources of water for the springs on 
the Refuge (Balleau et al. 1999, pp. 1-42). This study reported that 
the sources of water that will reach the Refuge's springs include a 
broad area beginning west of Roswell near Eightmile Draw, extending to 
the northeast to Salt Creek, and southeast to the Refuge. This area 
represents possible pathways that contaminants may enter the 
groundwater that feeds the springs on the Refuge. This broad area sits 
within a portion of the Roswell Basin and contains a mosaic of Federal, 
State, and private lands with multiple land uses, including expanding 
urban development.
    There are 378 natural gas and oil wells that are potential sources 
of groundwater contamination in the 12-township area encompassing the 
source-water capture zone for the springs where the four invertebrates 
occur on the Refuge (Go-Tech 2010). Of these, 17 oil and gas leases are 
currently within the habitat protection zone designated by the 
Department of the Interior's Bureau of Land Management (BLM) to reduce 
risk to the endangered Pecos gambusia (Gambusia nobilis) from drilling 
operations. The BLM habitat protection zone will also reduce risk to 
the four invertebrates from drilling operations because it protects the 
same source-water capture zone for the four invertebrates. This habitat 
protection zone encompasses 12,585 ac (5,093 ha) of the Federal mineral 
estate within the water resource area for the Refuge (U.S. Fish and 
Wildlife Service (Service) 2005a, pp. 3-8). Twenty natural gas wells 
currently exist on these leases. The BLM has estimated, according to 
well spacing requirements established by the New Mexico Oil 
Conservation Division (Service 2005a, pp. 4-6), a maximum potential 
development of 66 additional wells within the habitat protection zone. 
From 2002 to 2004, there were 200 notices of ``intentions to drill'' 
(59 on State, 33 on private, and 108 on Federal lands) filed for oil or 
natural gas in Chaves County (Go-Tech 2010).
    There are additional risks of groundwater contamination from 
accidental release of pollutants on State and private lands. Existing 
State regulations apply to all State and private lands where oil and 
gas operations occur and are designed to minimize the risk of spills 
and leaks. However, there are numerous examples in which oil and gas 
operations have met these regulatory standards within karst lands in 
New Mexico and other States, but where these measures failed to protect 
groundwater resources and prevent aquifer drawdown (Quarles 1983, p. 
155; Richard and Boehm 1989, p. 1). Groundwater contamination can be a 
serious threat because to clean the aquifer would be extremely 
difficult should it become contaminated by oil, chemicals, or organics, 
such as nitrates. In most cases, contamination of an underground 
aquifer by agricultural, industrial, or domestic sources is treated 
only at the source. When a contamination site is discovered, the source 
of the contamination is treated, and rarely do remediation efforts pump 
water from the aquifer and treat it before sending it back. This is 
largely because these techniques are very costly and difficult to apply 
(S. McGrath, pers. comm. 2001). Because these invertebrate species are 
sensitive to contaminants, efforts to clean up pollution after the 
aquifer has been contaminated may not be sufficient to protect these 
species and the aquatic habitat on which they depend.
    Currently there are two active gas wells on the Middle Tract of the 
Refuge that are upstream (within the underground watershed) of occupied 
habitat for the four invertebrates. In 2006, Yates Petroleum applied 
for two additional gas wells, one of which would have been just 
upstream of occupied habitat for the four invertebrates. The 
applications have since been withdrawn due to ecological concerns of 
the proposal (including possible effects on the four invertebrates and 
the endangered fish, Pecos gambusia) and other issues, although the 
potential for oil and gas development remains.
    The Diamond Y Springs Complex is within an active oil and gas 
extraction field. At this time there are still many active wells and 
pipelines located within 100 meters of the surface waters at the 
springs. In addition, a natural gas refinery is located within 0.5 mi 
(0.8 km) upstream of Diamond Y Spring. There are also old brine pits, 
which can contribute salt and other mineral pollutants to the 
groundwater, associated with previous drilling within feet of surface 
waters. In addition, oil and gas pipelines cross the spring outflow 
channels and marshes where the Pecos assiminea occurs, creating a 
constant potential for contamination from pollutants from leaks or 
spills. These activities pose a threat to the habitat of the Pecos 
assiminea by creating the potential for pollutants to enter underground 
aquifers that contribute to spring flow or for pollutants to 
contaminate the surface through spills and leaks of petroleum products.
    As an example of the likelihood of a spill occurring, in 1992, 
approximately 10,600 barrels of crude oil were released from a 6-in 
(15.2-cm) pipeline that traverses Leon Creek above its confluence with 
Diamond Y Draw. The oil was from a ruptured pipeline at a point several 
hundred feet away from the Leon Creek channel. The site itself is about 
1 mi (1.6 km) overland from Diamond Y Spring. The distance that surface 
runoff of oil residues must travel is about 2 mi (3.2 km) down Leon 
Creek to reach Diamond Y Draw. The pipeline was operated at the time of 
the spill by the Texas-New Mexico Pipeline Company, but ownership has 
since been transferred to several other companies. The Texas Railroad 
Commission has been responsible for overseeing cleanup

[[Page 33042]]

of the spill site. Remediation of the site initially involved 
aboveground land farming of contaminated soil and rock strata to allow 
microbial degradation. In recent years, remediation efforts have 
focused on vacuuming oil residues from the surface of groundwater 
exposed by trenches dug at the spill site. No impacts on the rare fauna 
of Diamond Y Springs Complex have been observed, but no specific 
monitoring of the effects of the spill was undertaken (Service 2005a, 
pp. 4-12).
    Water contamination is a significant threat for Noel's amphipod in 
the small spring vents (where the spring opens to the surface) along 
the Rio Hondo on the South Tract of the Refuge. One possible source of 
water contamination is runoff of agricultural fertilizers and 
pesticides that are applied to the croplands on the South Tract of the 
Refuge. This tract encompasses approximately 1,400 ac (570 ha) that are 
closed to public access. About 330 ac (130 ha) are used as agricultural 
cropland to provide food, habitat, and feeding areas for wintering 
migratory bird populations (Service 1998, p. 7). Alfalfa, corn, hegari, 
barley, winter wheat, sorghum, and other small grains are cultivated on 
this tract (Service 2010, p. 14). Although crop rotation minimizes the 
need for chemical fertilizers, both fertilizers and pesticides are used 
on this tract, and these chemicals have the potential to enter the 
springs inhabited by Noel's amphipod. Chemicals used on the South Tract 
in the past 10 years include Accent (Nicosulfuron), Banvel (Dicamba), 
Pounce (Permethrin), Roundup and equivalents (Glyphosate), Pursuit DG 
(Imazathapyr), Rhonox (2-ethylhexyl ester of 2-methyl-4-
chlorophenoxyacetic acid), Steadfast (Nicosulfuron/Rimsulfuron), 
Malathion 57 (Malathion), and Impact (Topramezone) (Service 2010, pp. 
43-44). To protect aquatic life in the Rio Hondo, the Refuge implements 
chemical-specific buffers within which the chemicals cannot be used. 
Additionally, restrictions are in place on Refuges prohibiting use of 
chemicals that dissolve and travel in groundwater. These restrictions 
and buffers serve to minimize exposure of Noel's amphipod to these 
chemicals. Nevertheless, there remains a potential for contamination 
and negative effects to Noel's amphipod and its habitat.
    The Refuge is in the process of reviewing the farming program on 
the South Tract. A draft environmental analysis (Service 2010, pp. 1-
55) evaluates the effects of several levels of farming on this tract. 
The current preferred alternative is to eliminate farming on the South 
Tract; if the draft environmental analysis is adopted, no future 
chemical application of fertilizers or pesticides would occur in the 
vicinity of Noel's amphipod populations, and this source of potential 
water contamination would be eliminated.
    Another potential source of water contamination in Noel's amphipod 
habitats on the South Tract is from periodic inundation by water from 
the Rio Hondo. The Rio Hondo is a perennial stream from Roswell to its 
confluence with the Pecos River, and its watershed extends eastward to 
the Sacramento Mountains. The majority of the lower Rio Hondo valley is 
used for extensive agricultural purposes, including ranching, 
commercial livestock feeding, and crop production, as well as 
residential land use (USACE 1974, p. 8). Stormwater runoff from areas 
with these land uses is one way contaminants can be transported into 
the Rio Hondo and into Noel's amphipod habitats. While we have no 
specific information on the water quality of the stormwater entering 
the Rio Hondo, stormwater runoff from other urban areas has been 
identified as potentially containing materials such as solids, 
plastics, sediment, nutrients, metals, pathogens, salts, oils, fuels, 
and various chemicals, including antifreeze, detergents, pesticides, 
and other pollutants that can be toxic to aquatic life (Burton and Pitt 
2002, pp. 6-7; Selbig 2009, p. 1).
    Another way the Rio Hondo receives contaminants is by wastewater 
effluent discharge (USACE 1974, p. 9; Smith 2000, p. 65). At the 
present time, the average return flow from City of Roswell Wastewater 
Treatment Facility is approximately 6.2 cfs (0.18 cms). Effluent from 
the Roswell Wastewater Treatment Facility is largely used for crop 
irrigation from February through November or is discharged to the North 
Spring River, which flows 5 mi (8 km) before entering the Rio Hondo 
(Smith 2000, p. 65; USEPA 2006, p. 2), upstream of the Noel's amphipod 
population. In 2010, the Roswell Wastewater Treatment Facility was 
modified to provide a higher level of water purification that should 
improve the quality of the effluent discharge (USEPA 2007, p. 5; J. 
Anderson, City of Roswell, pers. comm. December 9, 2010). However, some 
nutrients, bacteria, metals, pesticides, oxygen-demanding substances, 
organic chemicals, surfactants (materials that remove surface tension 
of water, such as soaps and detergents), flame retardants, personal 
care products, steroids, hormones, and pharmaceuticals are expected to 
remain in the Rio Hondo (USEPA 2009, pp. 26-39).
    Past analysis of water quality in the Rio Hondo has indicated some 
concerns. For example, sampling in the past yielded that total 
dissolved solids in Rio Hondo water averaged 935 milligrams per liter 
(mg/L), sulfates averaged 722 mg/L, and chlorides averaged 40 mg/L 
(USACE 1974, p. V-4) (both sulfates and chlorides are components of 
salt). However, more recent sampling by the New Mexico Environment 
Department (NMED) (2006a, p. 13) found higher total dissolved solids 
(average 7,321 mg/L), including more chloride (average 2,640 mg/L) and 
slightly more sulfate (average 776 mg/L) than reported by the U.S. Army 
Corps of Engineers (USACE 1974, p. V-4). In addition, the NMED (2006b, 
p. 32) identified water quality parameters of nutrients, bacteria, 
salinity, and temperature as a concern in the upper Rio Hondo 
watershed. Potential sources of nutrients or bacteria are municipal 
wastewater treatment facility effluents, onsite waste treatment systems 
(septic tanks), residential areas, landscape maintenance, livestock 
feeding operations, rangeland grazing, atmospheric deposition, stream 
modification or destabilization, and urban areas and construction sites 
(NMED 2006b, p. 32).
    Riverine conditions in the Rio Hondo are not suitable for Noel's 
amphipod; the amphipod is found only in the nearby springs. However, 
Noel's amphipod could be affected by river water entering the spring 
runs during periods of high flow by either flushing the amphipods 
downstream or by river water mixing with spring water and introducing 
contaminants or altered water chemistry to the spring habitats. The Rio 
Hondo has a base flow between 2 and 6 cfs (0.06 to 0.17 cms) but 
exceeds 10 cfs (0.03 cms; a flow high enough to inundate the springs) 
approximately 5 to 10 times per year for short durations (USGS 2010, p. 
1). Under base flow conditions, the spring runs that harbor Noel's 
amphipod are found along the riverbank at elevations higher than the 
stream, and, therefore, the water from the river does not mix with the 
spring outflow water. However, when Rio Hondo flows are elevated, these 
springs become inundated with water from the river, and the amphipods 
may be exposed to contaminants from the Rio Hondo. The impacts of any 
such contaminants would be lessened due to the high dilution rate of 
any treated wastewater discharge during a flood event.
    Groundwater that supplies the outflow to the springs where the 
amphipod occurs is an additional potential source of spring water

[[Page 33043]]

contamination. This water is clearly distinct from the water of the 
nearby Rio Hondo based on very different temperatures and low dissolved 
oxygen measurements (Lusk 2010, p. 1). Low dissolved oxygen is typical 
of spring water conditions, as oxygen enters the water mainly through 
the atmosphere (White et al. 1990, p. 584), and spring water 
temperatures remain much more constant throughout the year due to the 
insulating effect of soil and rock on groundwater (Constantz 1998, p. 
1610). The South Tract of the Refuge lies within the same groundwater 
source area as the Middle Tract, where the other Noel's amphipod 
populations are found and is, therefore, subject to the same threat of 
contamination from oil and gas activities as discussed above.
    There has been no research on the specific effects on Noel's 
amphipod of contaminants such as metals, pesticides, fertilizers, 
nutrients, or bacteria. However, there is some evidence that freshwater 
amphipods in the family Gammaridae (in particular, Gammarus) may 
require higher oxygen levels and less polluted water than some other 
amphipods such as Crangonyx (e.g., MacNeil et al. 1997, pp. 350, 356; 
MacNeil et al. 2000, p. 2). Gammarid amphipods (such as Noel's 
amphipod) may be considered an indicator of relatively unpolluted 
waters (MacNeil et al. 1997, p. 356; MacNeil et al. 2000, p. 6). 
Additionally, bacteria in high levels can affect amphipods directly 
through infections, or indirectly by depleting the dissolved oxygen in 
the water column through respiration or decomposition (Boylen and Brock 
1973, p. 631).
    In summary, special management efforts are needed to protect 
habitats of the four invertebrates from the potential effects of water 
contamination from oil and gas operations, agricultural activities, 
wastewater effluent, and stormwater runoff.
Wildfire
    Fire suppression efforts on the Refuge are largely restricted to 
established roads due to the safety hazards of transporting equipment 
over karst terrain. This severely limits the ability to quickly 
suppress fires that threaten fragile aquatic habitats on the Refuge. On 
March 5, 2000, the Sandhill wildfire burned 1,000 ac (405 ha) of the 
western portion of the Refuge, including portions of Bitter Creek. The 
fire burned through Dragonfly Spring, a spring in the headwaters of 
Bitter Creek, which is occupied habitat for Noel's amphipod and 
Koster's springsnail. The fire eliminated vegetation shading the 
spring, and generated a substantial amount of ash in the spring system 
(Lang 2002, p. 3; NMDGF 2005, p. 15). This resulted in the formation of 
dense algal mats, increased water temperature fluctuations, increased 
maximum water temperatures, and decreased dissolved oxygen levels (Lang 
2002, pp. 5-6). The pre-fire dominant vegetation of submergent aquatic 
plants and mixed native grasses within the burned area has also been 
replaced by the invasive common reed (Phragmites australis) (NMDGF 
2005, p. 15; 2008, p. 8). Following the fire at Dragonfly Spring, a 
dramatic reduction in Noel's amphipod was observed, and Koster's 
springsnail presently occurs at lower densities than were observed 
prior to the fire (Lang 2002, p. 7; NMDGF 2006a, p. 9). Strategically 
timed prescribed burns throughout the range of the species would 
significantly reduce fuel loads, limiting the risk of detrimental 
wildfires.
    Removal of vegetative cover by burning in habitats occupied by 
Pecos assiminea may be an important factor in decline or loss of 
populations (Taylor 1987, p. 5, NMDGF 2005, p. 16). It is likely that 
Pecos assiminea may survive fire or other vegetation reduction if 
sufficient litter and ground cover remain to sustain appropriate soil 
moisture and humidity at a microhabitat scale (Service 2004, pp. 4-5; 
NMDGF 2005, p. 16). Complete combustion of vegetation and litter, high 
soil temperatures during fire, or extensive vegetation removal 
resulting in soil and litter drying may create unsuitable habitat 
conditions and loss of populations (NMDGF 2005, p. 16). Pecos assiminea 
was discovered at Dragonfly Spring following the burning of habitat 
there during the Sandhill fire (NMDGF 2005, p. 16). Season of burning, 
intensity of the fire, and frequency of fire likely determine the 
magnitude of the fire's effects on Pecos assiminea population 
persistence and abundance (NMDGF 2005, p. 16), as the species has been 
found to persist in areas following fires (Lang 2002, p. B8). Pecos 
assiminea is relatively vulnerable to fires because the assiminea 
resides at or near the surface of the water.
    In summary, special management efforts are needed to correctly plan 
prescribed fires in order to protect habitats of the four invertebrates 
from the potential effects of wildfire.
Introduced Species
    Introduced species are one of the most serious threats to native 
aquatic species (Williams et al. 1989, p. 18; Lodge et al. 2000, p. 7). 
Because the distribution of the four invertebrates is so limited, and 
their habitat so restricted, introduction of certain nonnative species 
into their habitat could be devastating. Several invasive terrestrial 
plant species that may affect the invertebrates are present on the 
Refuge, including Tamarix spp. (saltcedar), common reed, and Salsola 
spp. (Russian thistle). Saltcedar, found on the Refuge and at Diamond Y 
Spring Complex and East Sandia Spring, threatens spring habitats 
primarily through the amount of water it consumes and from the chemical 
composition of the leaves that drop to the ground and into the springs. 
Saltcedar leaves that fall to the ground and into the water add salt to 
the system, as their leaves contain salt glands (DiTomaso 1998, p. 
333). Additionally, dense stands of common reed choke the stream 
channel, slowing water velocity and creating more pool-like habitat; 
this habitat is less suitable for Roswell and Koster's springsnails, 
which prefer flowing water. Finally, Russian thistle (tumbleweed) can 
create problems in spring systems by being blown into the channel, 
slowing flow and overloading the system with organic material (Service 
2005b, p. 2). In one case, even efforts to control nonnative vegetation 
by physical removal of the plants inadvertently caused local 
extirpations of populations of Pecos assiminea in New Mexico due to 
vegetation removal that resulted in soil and litter drying, thereby 
making the habitat unsuitable (Taylor 1987, p. 9; NMDGF 2005, p. 16).
    Nonnative mollusks have affected the distribution and abundance of 
native mollusks in the United States. Of particular concern for three 
of the invertebrates (Noel's amphipod, Roswell springsnail, and 
Koster's springsnail) is the red-rim melania (Melanoides tuberculata), 
a snail that can reach tremendous population sizes and has been found 
in isolated springs in the west. The red-rim melania has caused the 
decline and local extirpation of native snail species, and it is 
considered a threat to endemic aquatic snails that occupy springs and 
streams in the Bonneville Basin of Utah (Rader et al. 2003, p. 655). It 
is easily transported on fishing boats and gear or aquatic plants, and 
because it reproduces asexually (individuals can develop from 
unfertilized eggs), a single individual is capable of founding a new 
population. It has become established in isolated desert spring 
ecosystems such as Ash Meadows, Nevada, and Cuatro Ci[eacute]negas, 
Mexico, and in the 1990s, the red-rim melania became established in 
Diamond Y Springs Complex (Echelle 2001, p. 18). It has become the most 
abundant snail in the upper watercourse of the Diamond Y Springs 
Complex (Echelle 2001, p. 14). In many locations, this

[[Page 33044]]

exotic snail is so numerous that it essentially is the substrate in the 
small stream channel. The effect the species is having on native snails 
is not known; however, it probably has less effect on Pecos assiminea 
than on the other endemic aquatic snails present in the spring because 
it is aquatic.
    In summary, special management efforts are needed to protect the 
four invertebrates from the potential effects of invasive, nonnative 
terrestrial plants and invasive, nonnative snails.

Criteria Used To Identify Critical Habitat

    As required by section 4(b) of the Act, we used the best scientific 
and commercial data available in determining which areas should be 
designated as critical habitat for the four invertebrates. We relied on 
information from knowledgeable biologists and recommendations contained 
in State wildlife resource reports (Cole 1985, p. 102; Jones and 
Balleau 1996, pp. 1-16; Boghici 1997, pp. 1-120; Balleau et al. 1999, 
pp. 1-42; NMDGF 1999, pp. A1-B46; NMDGF 2006b, pp. 1-16; NMDGF 2007, 
pp. 1-20; NMDGF 2008, pp. 1-28) and the State recovery plan (NMDGF 
2005, pp. 1-80) in making this determination. We also reviewed the 
available literature pertaining to habitat requirements, historical 
localities, and current localities for these species. This includes 
data submitted during section 7 consultations and regional geographic 
information system (GIS) coverages.
    In accordance with the Act and its implementing regulation at 50 
CFR 424.12(e), we considered whether designating additional areas--
outside those currently occupied as well as those occupied at the time 
of listing--is necessary to ensure the conservation of the species. In 
revising critical habitat for the Pecos assiminea, and designating 
critical habitat for Roswell springsnail, Koster's springsnail, and 
Noel's amphipod, we selected areas within the geographical area 
occupied at the time of listing that contain the features essential to 
their conservation that may require special management considerations 
or protection. We also considered areas outside of the geographical 
area occupied at the time of listing to designate critical habitat for 
the four invertebrates, if the areas were considered essential to the 
conservation of the species.
Occupancy
    We consider an area to be occupied at the time of listing if 
Roswell springsnail, Koster's springsnail, Pecos assiminea, or Noel's 
amphipod were found to be present by species experts within 5 years of 
the listing in 2005, and no major habitat modification has occurred 
that would preclude their presence. Five years is an appropriate time 
period because surveys may not occur in all areas in all years. The 
species would be likely to persist in an area over multiple years 
unless major habitat modification occurred. We are designating as 
critical habitat all sites occupied by at least one of the four 
invertebrates at the time of listing because all of these areas contain 
the physical and biological features essential for the conservation of 
the species and require special management.
    Since the June 22, 2010, critical habitat proposal (75 FR 35375), 
we identified an additional site along the Rio Hondo on the South Tract 
of the Refuge that is occupied only by Noel's amphipod. We believe this 
site was occupied by Noel's amphipod at the time of listing because 
amphipods were first found at this site in 2006, one year after listing 
(Warrick 2006, p. 1). However, they were not taxonomically confirmed to 
be Noel's amphipod until 2010 (Berg 2010, p. 1; Lang 2010, p. 1). 
Because this spring area is isolated from other occupied areas and no 
reintroduction efforts have taken place, it has likely been occupied 
for a very long time, but appropriate surveys had not been previously 
conducted to verify it. We reasonably assume, therefore, that the site 
was occupied at the time of listing in 2005.
Essential Areas
    For areas not occupied by the species at the time of listing, the 
Service must demonstrate that these areas are essential to the 
conservation of the species in order to include them in a critical 
habitat designation.
    There are several locations within the historical range of the four 
invertebrates where the species no longer occur and that were not 
occupied at the time of listing. These areas include the South Spring 
River, Lander Springbrook, Berrendo Spring, and North Spring in New 
Mexico. These areas no longer contain the physical and biological 
features to support any of the four invertebrates. South Spring and 
Lander Spring are both dry due to aquifer depletion (Cole 1981, p. 27; 
Jones and Balleau 1996, p. 5), and reaches of Berrendo Creek (the 
springbrook from Berrendo Spring) remain dry and unable to support the 
invertebrates (NMDGF 2005, p. 18). North Spring, located on the grounds 
of the Roswell Country Club, was enclosed by a brick wall, native 
vegetation was removed from the margins of the springhead and 
springbrook, and the banks were sodded (Cole 1988, p. 2; NMDGF 2005, p. 
18). The brick wall at North Spring has since been removed and the 
spring outflow has been widened, allowing a nearby pond to back into 
the spring, introducing carp to the system (B. Lang, NMDGF, pers. 
comm., 2010). Springsnails have not been found at North Spring since 
1995, and suitable habitat is not present there.
    Because these formerly occupied sites have been so severely