thefederalregister.com

Daily Rules, Proposed Rules, and Notices of the Federal Government

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2012-0082; 4500030114]

RIN 1018-AY20

Endangered and Threatened Wildlife and Plants; Proposed Revision of Critical Habitat for the Comal Springs Dryopid Beetle, Comal Springs Riffle Beetle, and Peck's Cave Amphipod

AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to revise designation of critical habitat for the Comal Springs dryopid beetle (Stygoparnus comalensis), Comal Springs riffle beetle (Heterelmis comalensis), and Peck's cave amphipod (Stygobromus pecki), under the Endangered Species Act of 1973, as amended (Act). In total, approximately 169 acres (68 hectares) are being proposed for revised critical habitat. The proposed revision of critical habitat is located in Comal and Hays Counties, Texas.
DATES: We will accept comments received or postmarked on or before December 18, 2012. Comments submitted electronically using the Federal eRulemaking Portal (seeADDRESSESsection, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown inFOR FURTHER INFORMATION CONTACTby December 3, 2012.
ADDRESSES: (1)Electronically:Go to the Federal eRulemaking Portal:http://www.regulations.gov.In the Search box, enter FWS-2-ES-2012-0082, which is the docket number for this rulemaking. You may submit a comment by clicking on "Comment Now!."

(2)By hard copy:Submit by U.S. mail or hand-delivery to: Public CommentsProcessing, Attn: FWS-R2-ES-2012-008,; Division of Policy and Directives Management; U.S. Fish and Wildlife Service, 4401 N. Fairfax Drive, MS 2042-PDM, Arlington, VA 22203.

We request that you send comments only by the methods described above. We will post all comments onhttp://www.regulations.gov.This generally means that we will post any personal information you provide us (see Information Requested section below for more information).

The coordinates or plot points or both from which the maps are generated are included in the administrative record for this critical habitat designation and are available at (http://www.fws.gov/southwest/es/austintexas/),www.regulations.govat Docket No. FWS-R2-ES-2012-0082, and at the Austin Ecological Services Field Office (seeFOR FURTHER INFORMATION CONTACT). Any additional tools or supporting information that we may develop for this critical habitat designation will also be available at the Fish and Wildlife Service Web site and field office set out above, and may also be included in the preamble and/or atwww.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor, U.S. Fish and Wildlife Service, Austin Ecological Services Field Office, 10711 Burnet Road, Suite 200, Austin, TX 78758; telephone at 512-490-0057 extension 248; or by facsimile at 512-490-0974. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION: Executive Summary

Why we need to publish a rule.Under the Endangered Species Act, any species that is determined to be threatened or endangered requires critical habitat to be designated, to the maximum extent prudent and determinable. Designations and revisions of critical habitat can only be completed by issuing a rule. This is a proposed rule to revise critical habitat for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod. With this rule, we are proposing to revise critical habitat for the three endangered invertebrates as follows:

• Comal Springs dryopid beetle: 39.4 acres (ac) (15.56 hectares (ha)) of surface and 139 ac (56 ha) of subsurface critical habitat. The original designation was surface critical habitat of 39.5 ac (16.0 ha) without subsurface;

• Comal Springs riffle beetle: 54 ac (22 ha) of surface critical habitat only. The original designation was surface critical habitat of 30.3 ac (12.3 ha) ; and

• Peck's cave amphipod: 38.4 ac (15.16 ha) surface and 138 ac (56 ha) of subsurface critical habitat. The original designation was surface critical habitat of 38.5 ac (15.6 ha) without subsurface.

• Areas that meet the definition of critical habitat for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod species that are covered by the Edwards Aquifer Recovery Implementation Program Habitat Conservation Plan are being considered for exclusion from the final critical habitat designation.

The proposed critical habitat revision is located in Comal and Hays Counties, Texas.

The basis for our action.Previously, we designated critical habitat for these three invertebrates on July 17, 2007 (72 FR 39248). However, on January 14, 2009, the Center for Biological Diversity, Citizens Alliance for Smart Expansion, and Aquifer Guardians in Urban Areas (CBD, et al.v.Kempthorne, No.1:09-cv-00031-LY (W.D. Tex.)) filed suit in Federal Court (Western District of Texas) alleging that the Service failed to use the best available science in the critical habitat designation. On December 18, 2009, the parties filed a settlement agreement where we agreed to submit a revised proposed critical habitat determination for publication in theFederal Registerby October 17, 2012, and a final revised determination by October 13, 2013. This proposed rule is published in accordance with that agreement.

We are preparing an economic analysis.To ensure that we consider the economic impacts, we are preparing a new economic analysis of the proposed designation. We will publish an announcement and seek public comments on the draft economic analysis when it is completed.

We will seek peer review.We are seeking comments from independent specialists to ensure that our critical habitat designation is based on scientifically sound data, assumptions, and analyses. We have invited these peer reviewers to comment on our specific assumptions in this revision of the critical habitat designations. Because we will consider all comments and information received during the comment period, our final determinations may differ from this proposal.

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other concerned government agencies, the scientific community, industry, or any other interested party concerning this proposed rule. We particularly seek comments concerning:

(1) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531et seq.) including whether there are threats to the species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threat outweighs the benefit of designation such that the designation of critical habitat may not be prudent.

(2) Specific information on:

(a) The amount and distribution of the three invertebrates' habitats;

(b) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of the species, should be included in the designation and why;

(c) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change; and

(d) What areas not occupied at the time of listing are essential for the conservation of the species and why.

(3) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.

(4) Information on the projected and reasonably likely impacts of climate change on the Comal Springs dryopid beetle, Comal Springs riffle beetle, Peck's cave amphipod, or their proposed critical habitat revision.

(5) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation; in particular, any impacts on small entities or families, and the benefits of including or excluding areas that exhibit these impacts.

(6) Any data documenting the extent of subsurface areas used by any of the species for breeding, feeding, or sheltering.

(7) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act, in particular for those areas that may benefit from the proposed Edwards Aquifer Recovery ImplementationProgram Habitat Conservation Plan (HCP). Copies of the draft HCP are available from the Austin Ecological Services Field Office (seeFOR FURTHER INFORMATION CONTACT).

(8) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.

You may submit your comments and materials concerning this proposed rule by one of the methods listed inADDRESSES. We request that you send comments only by the methods described in theADDRESSESsection.

We will post your entire comment—including your personal identifying information—onhttp://www.regulations.gov.You may request at the top of your document that we withhold personal information such as your street address, phone number, or email address from public review; however, we cannot guarantee that we will be able to do so.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection onhttp://www.regulations.gov,or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Austin Ecological Services Field Office (seeFOR FURTHER INFORMATION CONTACT).

Previous Federal Actions

The final rule to list Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod as endangered species was published in theFederal Registeron December 18, 1997 (62 FR 66295). Critical habitat was not designated at the time of listing due to the determination by the Service that designation for the three invertebrate species would not provide benefits to the species beyond listing and any evaluation of activities required under section 7 of the Act. The lack of designated critical habitat for these species was subsequently challenged by the Center for Biological Diversity in the U.S. District Court for the District of Columbia. As part of a stipulated settlement agreement between the plaintiff and the Service, the Service subsequently proposed critical habitat on July 17, 2006 (71 FR 40588), and designated critical habitat for the species on July 17, 2007 (72 FR 39248).

On August 28, 2007, the Center for Biological Diversity, Citizens Alliance for Smart Expansion, and Aquifer Guardians in Urban Areas provided us with a 60-day notice of intent to sue on the final critical habitat rule. On January 14, 2009, the plaintiffs filed suit in Federal Court (Western District of Texas) alleging that the Service failed to use the best available science. On December 18, 2009, the parties filed a settlement agreement where we agreed to submit a revised proposed critical habitat determination for publication in theFederal Registerby October 17, 2012, and a final revised determination by October 13, 2013. This proposed rule is published in accordance with that agreement.

Background

For more information on these species, refer to the final rule listing the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod that published in theFederal Registeron December 18, 1997 (62 FR 66295) and the San Marcos & Comal Springs & Associated Aquatic Ecosystems (Revised) Recovery Plan (Service 1996), available online athttp://ecos.fws.gov/docs/recovery_plan/960214.pdf.

Species Information

The Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod are all freshwater invertebrates (Gibsonet al.2008, p. 74). The Comal Springs dryopid beetle has been found in two spring systems (Comal Springs and Fern Bank Springs) that are located in Comal and Hays Counties, Texas, respectively (Barr and Spangler 1993, pp. 3, 41). The Comal Springs dryopid beetle is a subterranean insect with vestigial (poorly developed, nonfunctional) eyes (Barr and Spangler 1992, pp. 40-41). The Comal Springs dryopid beetle larvae are thought to inhabit moist areas associated with roots, debris, and soil lining the ceiling of subterranean cavities and spring orifices (Barr and Spangler 1992, p. 41; Gibson, R. 2012d, pers. comm.).

The Comal Springs riffle beetle is an aquatic insect that is primarily surface-dwelling associated with Comal Springs in Comal County and San Marcos Springs in Hays County (Gibsonet al.2008, pp. 74, 76).

The Peck's cave amphipod is an eyeless, subterranean (below ground) arthropod that has been found in Comal Springs and Hueco Springs (also spelled Waco Springs), both located in Comal County (Barr 1993, pp. 3, 37, 52). The Peck's cave amphipod is likely an omnivore capable of consuming detritus and microorganisms from decaying roots near spring outlets as well as acting as a scavenger or predator inside the aquifer (Gibson, R. 2005, pers. comm.).

Potential food sources for all three invertebrate species include detritus (decomposed materials), leaf litter, and decaying roots. Roots not only provide a food source to these invertebrates, but penetrate underground into water pools where they can also serve as habitat for the amphipod and dryopid beetle. These invertebrate species are typically found on roots where they feed on fungus and bacteria (Gibsonet al.2008, p. 77, Gibson, R. 2012d pers. comm.).

Habitat Information

The four spring systems—Comal, San Marcos, Hueco, and Fern Bank—where these three invertebrate species occur are produced by discharge of aquifer water along the Balcones Fault Zone at the edge of the Edwards Plateau in central Texas (Gibsonet al.2008, p. 74). These spring systems vary in size. Comal Springs and San Marcos Springs are the two largest spring systems in Texas with respective mean annual flows of 284 and 170 cubic feet per second (8 and 5 cubic meters per second) (Fahlquist and Slattery 1997, p. 1; Slattery and Fahlquist 1997, p. 1). Fern Bank Springs and Hueco Springs have considerably smaller flows, and each consists of one main spring with several satellite springs or seep areas.

The source of water flows for Comal Springs and San Marcos Springs is the San Antonio segment of the Edwards Aquifer (Lindgrenet al.2004, pp. 4-6; Lindgrenet al.2009, p. 2). This aquifer is characterized by highly varied, below ground spaces that have been hollowed out within limestone bedrock through dissolution by rainwater. Hueco Springs is recharged from the local watershed basin and possibly by the San Antonio segment of the Edwards Aquifer (Guyton and Associates 1979, p. 2). The source of water for Fern Bank Springs has not been determined, but it is speculated it could be drainage from the nearby Edwards Aquifer Recharge Zone, water lost from the Blanco River, or a combination of these possible sources (Veni, G. 2006, pers. comm.).

The four spring systems proposed for critical habitat revision are characterized by high water quality and relatively constant water flows. Although flows from San Marcos Springs can vary according to fluctuations in the source aquifer, records indicate that this spring system has never ceased flowing since 1894 (Puente 1976, p. 27). Comal Springs has a flow record nearly comparable; however, Comal Springs ceased flowing from June 13 to November 3, 1956, during a severe drought in conjunction with water being pumped from the aquifer (U.S. Army Corps of Engineers1965, p. 59). Unlike the Comal and San Marcos Springs, the Hueco Springs has gone dry a number of times in the past during drought periods (Puente 1976, p. 27; Guyton and Associates 1979, p. 46). Although flow records are unavailable for Fern Bank Springs, the spring system may be perennial (Barr 1993, p. 39).

Each of the four spring systems and related subterranean aquifers typically provide adequate resources to sustain life cycle functions for resident populations of the Comal Springs dryopid beetle, Comal springs riffle beetle, and the Peck's cave amphipod except during extreme drought periods or from excessive groundwater pumping.

New Genetic Information Since the 2007 Final Critical Habitat Rule

A recent analysis of known Peck's cave amphipod populations examined genetic variation to assess population structure within the species (Nice and Ethridge 2011, p. 2). This study estimated the degree to which the sampling localities of this species were differentiated or isolated from each other. Nice and Ethridge (2011, pp. 7-8) found that genetic sequences showed high levels of differentiation within and among Peck's cave amphipodlocalities. They also found sequences from two distinct haplotypes (a genetic segment or group of genes inherited from a single parent) with deep divergence (Nice and Ethridge 2011, pp. 7-8). The two haplotypes were not geographically separated and often co-occurred in similar proportions. This observation suggests that what appears to be a single species of Peck's cave amphipod might instead be two similar-looking species living together that do not interbreed. Another explanation could be that a common ancestor separated some time ago causing divergence that resulted in two core subterranean populations isolated by hydrogeology. Then over time, these populations reconnected at Comal Springs via a downstream dispersal mechanism while dispersal upstream into the aquifer (mixing of core populations) might be hindered. For example, predation and competition with the established community and hydrogeological features such as underground waterfalls, tight interstitial spaces, and high flow conduits might allow immature individuals to pass downstream but block upstream dispersal (Gibson 2012a, pers. comm.). Despite this new information, a formal, peer-reviewed description of the two possible species has not been published. Therefore, we do not recognize a separation of the Peck's cave amphipod into two species because this split has not been recognized by the scientific community.

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, 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 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 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.

Under the first prong of the Act's definition of critical habitat, areas within the geographical area occupied by the species at the time it was listed are included in a critical habitat designation if they contain physical or biological features (1) which are essential to the conservation of the species and (2) which may require special management considerations or protection. For these areas, critical habitat designations identify, to the extent known using the best scientific and commercial data available, those physical or biological features that are essential to the conservation of the species (such as space, food, cover, and protected habitat). In identifying those physical and biological features within an area, we focus on the principal biological or physical constituent elements (primary constituent elements such as roost sites, nesting grounds, seasonal wetlands, water quality, tide, soil type) that are essential to the conservation of the species. Primary constituent elements are the specific elements of physical or biological features that provide for a species' life-history processes and are essential to the conservation of the species.

Under the second prong of the Act's definition of critical habitat, 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. For example, an area currently occupied by the species but that was not occupied at the time of listing may be essential to the conservation of the species and may be included in the critical habitat designation. 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.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific data available. Further, our Policy on Information Standards under the Endangered Species Act (published in theFederal Registeron 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, other unpublished materials, or experts' opinions or personal knowledge.

Habitat is dynamic, and species may move from one area to another over time. 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 needed 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 ensure 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.

Prudency Determination

Section 4(a)(3) of the Act, as amended, and implementing regulations (50 CFR 424.12), require that, to the maximum extent prudent and determinable, the Secretary shall designate critical habitat at the time the species is determined to be an endangered or threatened species. Our regulations (50 CFR 424.12(a)(1)) state that the designation of critical habitat is not prudent when one or both of the following situations exist:

(1) The species is threatened by taking or other human activity, and identification of critical habitat can be expected to increase the degree of threat to the species, or

(2) Such designation of critical habitat would not be beneficial to the species.

There is currently no imminent threat of take attributed to collection or vandalism for any of these species, and identification and mapping of critical habitat is not expected to initiate any such threat. In the absence of finding that the designation of critical habitat would increase threats to a species, if there are any benefits to a critical habitat designation, then a prudent finding is warranted. Here, the potential benefits of designation include: (1) Triggering consultation under section 7 of the Act, in new areas for actions in which there may be a Federal nexus where it would not otherwise occur because, for example, it is or has become unoccupied or the occupancy is in question; (2) focusing conservation activities on the most essential features and areas; (3) providing educational benefits to State or county governments or private entities; and (4) preventing people from causing inadvertent harm to the species. Therefore, because we have determined that the designation of critical habitat will not likely increase the degree of threat to the species and may provide some measure of benefit, we find that designation of critical habitat is prudent for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod, and reaffirmed our previous determination concerning the prudency of designating critical habitat for these species.

Critical Habitat Determinability

Having reaffirmed that designation is prudent, under section 4(a)(3) of the Act we then evaluate whether critical habitat for the eight species is determinable. Our regulations at 50 CFR 424.12(a)(2) state that critical habitat is not determinable when one or both of the following situations exist:

(i) Information sufficient to perform required analyses of the impacts of the designation is lacking, or

(ii) The biological needs of the species are not sufficiently well known to permit identification of an area as critical habitat. When critical habitat is not determinable, the Act allows the Service an additional year to publish a critical habitat designation (16 U.S.C. 1533(b)(6)(C)(ii)).

We reviewed the available information pertaining to the biological needs of the species and habitat characteristics where these species are located. This and other information represent the best scientific data available and led us to conclude that the designation of critical habitat is determinable for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod.

Physical or Biological Features

In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and regulations at 50 CFR 424.12, in determining which areas within the geographical area occupied by the species at the time of listing to designate as critical habitat, we consider the physical or biological features that are essential to the conservation of the species and which 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 historical, geographic, and ecological distributions of a species.

We derive the specific physical or biological features essential for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod from studies of this species' habitat, ecology, and life history as described below. Additional information can be found in the final listing rule published in theFederal Registeron December 18, 1997 (62 FR 66295), the previous critical habitat designation (72 FR 39248, July 17, 2007), the Revised Recovery Plan (Service 1996), and the draft Edwards Aquifer Recovery Implementation Program Habitat Conservation Plan (HCP). We have determined that the following physical or biological features are essential for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod:

Space for Individual and Population Growth and for Normal Behavior

Very little is known regarding the space needed by the three invertebrate species for individual and population growth and for normal behavior. The Peck's cave amphipod and Comal Springs dryopid beetle are most commonly found in subterranean areas where plant roots are inundated or otherwise influenced by aquifer water. Gibsonet al.(2008) found Peck's cave amphipod in gravel, rocks, and organic debris (leaves, roots, wood) immediately inside of or adjacent to springs, seeps, and upwellings of Comal Springs and their impoundment, Landa Lake. They were not observed in nearby surface habitats. Gibsonet al.(2008, p. 76) collected Peck's cave amphipods in drift nets (a net that floats freely on surface water) which were placed over spring openings at Hueco and Comal springs. At Panther Canyon Well, specimens were collected in a baited bottle trap, which is located about 360 feet (ft) (110 meters (m)) from Comal Spring Run No. 1 (Gibsonet al.2008, p. 76; R. Gibson 2012b, pers. comm.). Gibsonet al.(2008, p. 77), also found Comal Springs riffle beetles in drift nets at Comal Springs that were placed in or over spring openings. Therefore, based on the information above, we identify springs, associated streams, and underground spaces immediately inside of or adjacent to springs, seeps, and upwellings to be a primary component of the physical or biological features essential to the conservation of the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod.

Food, Water, Air, Light, Minerals, or Other Nutritional or Physiological Requirements

Food—Although specific food requirements of the three invertebrate species are unknown, potential food sources for all three invertebrate species include detritus (decomposed plant materials), leaf litter, and decaying roots. It is possible that the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod all feed on microorganisms such as bacteria and fungi associated with decaying riparian vegetation. Both beetle species likely are detritivores (detritus-feeding animals) that consume detrital materials from spring-influenced riparian (associated with rivers, creeks, or other water bodies) zones (Brown 1987, p. 262; Gibsonet al.2008, p. 77). Riparian vegetation is likely important for these species as they are typically found on roots where they feed on fungus and bacteria (Gibsonet al.2008, p. 77, Gibson 2012c, pers. comm.). Larvae of the Comal Springs dryopid beetle are also presumed to feed on bacteria and fungi associated with roots, debris, and soil lining the ceilings of subterranean cavities (Barr and Spangler 1992, p. 41). Available evidence suggests Peck's cave amphipod is likely an omnivore (consumes everything available including both animal and plant matter). It can feed as a scavenger or predator within the aquifer and as a detrivore where plant roots are exposed providing a medium for microbial growth as well as a food source to potential prey (Gibson 2012a, pers. comm.). Among other things, trees and shrubs in riparian areas adjacent to the spring system provide plant growth necessary to maintain food sources such as decaying material for these invertebrates. Roots from trees and shrubs in proximity to spring outlets are most likely to penetrate underground down to the water pools where these roots can serve as habitat for the amphipod and dryopid beetle.

Therefore, based on the information above, we identify sources of detritus (decomposed materials), leaf litter, and decaying roots of riparian vegetation to be primary components of the physical or biological features essential to the conservation of the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod.

Water—The Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod are all spring-adapted, aquatic species dependent on high-quality, unpolluted groundwater that has low levels of salinity and turbidity. The two beetle species are generally associated with water that has adequate levels of dissolved oxygen for respiration (Brown 1987, p. 260; Arsuffi 1993, p. 18). High-quality discharge water from springs and adjacent subterranean areas help sustain habitat components essential to these three aquatic invertebrate species.

The temperature of spring water emerging from the Edwards Aquifer at Comal Springs and San Marcos Springs ordinarily occurs within a narrow range of approximately 72 to 75 Fahrenheit degrees (°F) (22 to 24 Celsius degrees (°C)) (Fahlquist and Slattery 1997, pp. 3-4; Groegeret al.1997, pp. 282-283). Hueco Springs and Fern Bank Springs have temperature records of 68 to 71°F (20 to 22 °C) (George 1952, p. 52; Brune 1975, p. 94; Texas Water Development Board 2006, p. 1). The three listed invertebrate species complete their life-cycle functions within these relatively narrow temperature ranges.

Each of these four spring systems typically provide adequate resources to sustain life-cycle functions for resident populations of the Comal Springs dryopid beetle, Comal Springs riffle beetle, or Peck's cave amphipod. However, a primary threat to the three invertebrate species is the potential failure of spring flow due to drought or groundwater pumping, which could result in loss of aquatic habitat for the species.

Barr (1993, p. 55) found Comal Springs dryopid beetles in spring flows with low- and high-volume discharge and suggested that presence of the species was not necessarily dependent on high spring flow. However, Barr (1993, p. 61) noted that effects on both subterranean species (dryopid beetle and amphipod) from extended loss of spring flow and low aquifer levels could not be predicted since details of their life cycles are unknown.

Riffle beetles are most commonly associated with flowing water that has shallow riffles or rapids (Brown 1987, p. 253). Riffle beetles are restricted to waters with high dissolved oxygen due to their reliance on a plastron (thin sheet of air held by water-repellent hairs of some aquatic insects) that is held next to the surface of the body by a mass of water-repellent hairs. The mass of water-repellent hairs function as a physical gill by allowing oxygen to passively diffuse from water into the plastron in order to replace oxygen absorbed during respiration (Brown 1987, p. 260). However, slow-moving insects like riffle beetles are limited to habitats with high oxygen levels because oxygen will diffuse away from the beetle if concentrations are higher in the plastron than in the surrounding water (Reshet al.2008, pp. 44-45).

Bowleset al.(2003, p. 379) pointed out that the mechanism by which the Comal Springs riffle beetle survived the 1950s drought and the extent to which its population was negatively impacted are unknown. Bowleset al.(2003, p. 379) speculated that the riffle beetle may be able to retreat back into spring openings or burrow down to the hyporheos (groundwater zone) below the stream channel. In reference to the Comal Springs population of the riffle beetle, Bowleset al.(2003, p. 380) stated that “Reductions in water levels in the Edwards Aquifer to the extent that spring-flows cease likely would have devastating effects on * * * [this] population of this species and could result in its extinction.”

Therefore, based on the information above, we identify unpolluted, high-quality water with stable temperatures flowing through subterranean habitatand exiting at spring openings to be primary components of the physical or biological features essential to the conservation of the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod.

Habitats Protected From Disturbance or Representative of the Historical, Geographic, and Ecological Distributions of the Species

These freshwater invertebrates rely on spring water that follows established hydrological flow paths within a limestone aquifer before emerging. Water inside limestone aquifers flows through fractures, pores, cave stream channels, and conduits (open channels) that have been hollowed out within the limestone by dissolution processes (White 1988, pp. 119-148, 150-151). Alteration of subsurface water flows through destruction of geologic features (for example, excavation) or creation of impediments to flow (for example, concrete filling) in proximity to spring outlets could negatively alter the hydraulic connectivity necessary to sustain these species. Areas of subsurface habitat must remain intact to provide adequate space for feeding, breeding, and sheltering of the two subterranean species (amphipod and dryopid beetle). In addition, subsurface habitat must remain intact with sufficient hydraulic connectivity of flow paths and conduits to ensure that other constituent elements (water quality, water quantity, and food supply) for the proposed critical habitat remain adequate for all three listed invertebrates.

Although Comal Springs riffle beetles occur in conjunction with a variety of bottom substrates that underlay these flow paths, Bowleset al.(2003, p. 372) found that these beetles mainly occurred in areas with gravel and cobble ranging between 0.3 to 5.0 in (inches) (8 to 128 millimeters (mm)) and did not occur in areas dominated by silt, sand, and small gravel. Collection efforts in areas of high sedimentation generally do not yield riffle beetles (Bowleset al.2003, p. 376; Gibson, 2012d, pers. comm.).

Therefore, based on the information above, we identify spring water that follows established hydrological flow paths within a limestone aquifer to be a primary component of the physical or biological features essential to the conservation of the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod.

Primary Constituent Elements for the Comal Springs Dryopid Beetle, Comal Springs Riffle Beetle, and Peck's Cave Amphipod

Under the Act and its implementing regulations, we are required to identify the physical or biological features essential to the conservation of the three invertebrates 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 or biological features that provide for a species' life-history processes and are essential to the conservation of the species.

Based on our current knowledge of the physical or biological features and habitat characteristics required to sustain the species' life-history processes, we determine that the primary constituent elements specific to the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod are:

(1) Springs, associated streams, and underground spaces immediately inside of or adjacent to springs, seeps, and upwellings that include:

(a) High-quality water with no or minimal pollutant levels of soaps, detergents, heavy metals, pesticides, fertilizer nutrients, petroleum hydrocarbons, and semivolatile compounds such as industrial cleaning agents; and

(b) Hydrologic regimes similar to the historical pattern of the specific sites must be present, with continuous surface flow from the spring sites and in the subterranean aquifer.

(2) Spring system water temperatures that range from 68 to 75 °F (20 to 24 °C).

(3) Food supply that includes, but is not limited to, detritus (decomposed materials), leaf litter, living plant material, algae, fungi, bacteria, other microorganisms, and decaying roots.

With this proposed designation of critical habitat, we intend to identify the physical or biological features essential to the conservation of the species, through the identification of the features' primary constituent elements sufficient to support the life-history processes of the species. All units proposed to be revised as critical habitat designation are currently occupied by one or more of the three 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 geographic area occupied by the species at the time of listing contain features, which are essential to the conservation of the species and which may require special management considerations or protection.

For the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod, threats to adequate water quantity and quality (PCEs 1 and 2) include alterations to the natural flow regimes affecting the aquifer recharge system and its associated springs, streams, and riparian areas. Threats to water quantity and quality include water withdrawals, impoundment, and diversions; hazardous material spills; stormwater drainage pollutants including soaps, detergents, pharmaceuticals, heavy metals, fertilizer nutrients, petroleum hydrocarbons, and semivolatile compounds such as industrial cleaning agents; pesticides and herbicides associated with pathogenic organisms or invasive species; invasive species altering the surface habitat; excavation and construction surrounding the springs and in the watershed; and climate change. All of these threats are known to be ongoing at various levels in and around the Edwards Aquifer ecosystem. Examples of management actions that would ameliorate these threats include: (1) Maintenance of sustainable groundwater use and subsurface flows; (2) use of adequate buffers for water quality protection; (3) selection of appropriate pesticides and herbicides; and (4) implementation of integrated pest management plans to manage existing invasive species as well as preventing the introduction of additional invasive species.

Climate change could potentially affect water quantity and spring flow as well as the food supply (PCEs 1, 2, and 3) for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's Cave amphipod. According to the Intergovernmental Panel on Climate Change (IPCC; 2007, p. 1), “warming of the climate system is unequivocal, as is now evident from observations of increases in global averages of air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.” Localized projections suggest the southwestern United States may experience the greatest temperature increase of any area in the lower 48 States (IPCC 2007, p. 8), with warming increases in southwestern States greatest in the summer. The IPCC also predicts hot extremes, heat waves, and heavy precipitation will increase in frequency (IPCC 2007, p. 8).

The degree to which climate change will affect habitats of the Comal Springsdryopid beetle, Comal Springs riffle beetle, and Peck's Cave amphipod is uncertain. Climate change will be a particular challenge for biodiversity in general because the interaction of additional stressors associated with climate change and current stressors may push species beyond their ability to survive (Lovejoy 2005, pp. 325-326). The synergistic implications of climate change and habitat fragmentation are the most threatening facets of climate change for biodiversity (Hannah and Lovejoy 2005, p. 4). Current climate change predictions for terrestrial areas in the Northern Hemisphere indicate warmer air temperatures, more intense precipitation events, and increased summer continental drying (Fieldet al.1999, pp. 1-3; Hayhoeet al.2004, p. 12422; Cayanet al.2005, p. 6; IPCC 2007, p. 1181). Climate change may lead to increased frequency and duration of severe storms and droughts (McLaughlinet al.2002, p. 6074; Cooket al.2004, p. 1015; Golladayet al.2004, p. 504).

An increased risk of drought could occur if evaporation exceeds precipitation levels in a particular region due to increased greenhouse gases in the atmosphere (CH2M HILL 2007, p. 18). The Edwards Aquifer is also predicted to experience additional stress from climate change that could lead to decreased recharge and low or ceased spring flows given increasing pumping demands (Loáicigaet al.2000, pp. 192-193). CH2M HILL (2007, pp. 22-23) identified possible effects of climate change on water resources within the Lower Colorado River Watershed (which contributes recharge to Barton Springs). Barton Springs is fed by the Barton Springs segment of the Edwards Aquifer, not far to the north of the area used by these invertebrates. A reduction of recharge to aquifers and a greater likelihood for more extreme droughts were identified as potential impacts to water resources (CH2M HILL 2007, p. 23). The droughts of 2008-2009 and 2010-2011 were two of the worst short-term droughts in central Texas history, with the period from October 2010 through September 2011 being the driest 12-month period in Texas since rainfall records began (Lower Colorado River Authority (LCRA) 2011, p. 1). As a result, the effects of climate change could compound the threat of decreased water quantity due to drought.

Criteria Used To Identify Critical Habitat

As required by section 4(b)(2) of the Act, we use the best scientific data available to designate critical habitat. We review available information pertaining to the habitat requirements of the species. In accordance with the Act and its implementing regulation at 50 CFR 424.12(e), we consider whether designating additional areas—outside those currently occupied as well as those occupied at the time of listing—are necessary to ensure the conservation of the species. We are proposing to designate critical habitat in areas within the geographical area occupied by the species at the time of listing in 1997.

During our preparation for proposing critical habitat for these three endangered invertebrate species, we reviewed the best available scientific information including: (1) Historical and current occurrence records, (2) information pertaining to habitat features for these species, and (3) scientific information on the biology and ecology of each species. We have also reviewed a number of studies and surveys of the three listed invertebrates including: Holsinger (1967), Bosseet al.(1988), Barr and Spangler (1992), Arsuffi (1993), Barr (1993), Bio-West (2001), Bio-West (2002a), Bio-West (2002b), Bio-West (2003), Bowleset al.(2003), Bio-West (2004), Frieset al.(2004), and Gibsonet al.(2008).

Based on this review, the proposed critical habitat areas described below constitute our best assessment at this time of areas that: (1) Are within the geographical range occupied by at least one of the three invertebrate species, and (2) contain features essential to the conservation of these species which may require special management considerations or protections. All areas proposed to be designated as critical habitat are occupied by at least one of the three invertebrates and contain sufficient primary constituent elements to support the life functions of the resident species. We defined the boundaries of each species based on the below criteria.

Comal Springs Dryopid Beetle

We identified both surface and subsurface components of critical habitat for this species, which has been found in Comal Springs and Fern Bank Springs in Comal and Hays Counties, Texas. However, this species was recently collected from Panther Canyon Well, located about 360 ft (110 m) away from the spring outlet of Spring Run No. 1 (Barr and Spangler 1992, p. 42; Gibson 2012e, pers. comm.). Collections made from 2003 to 2009 further extended the known range of the beetle within the Comal Springs system to all major spring runs, seeps along the western shoreline of Landa Lake (the impounded portion of the Comal Springs system), Landa Lake upwellings in the Spring Island area, and Panther Canyon Well (Bio-West, Inc. 2003, p. 34; Bio-West 2004, pp. 5-6; Bio-West 2005, pp. 5-6; Bio-West 2006, p. 37; Bio-West to 2009, pp. 40-43; R. Gibson 2012e, pers. comm.). This information indicates that the Comal Springs dryopid beetle can travel through the aquifer up to a distance of 360 ft (110 m); therefore, we used this distance from spring outlets to identify the subsurface area of critical habitat for this species.

To determine surface critical habitat, we used an area consisting of a 50-ft (15-m) distance from spring outlets. We used this area because this distance has been found to contain food sources where plant roots interface with water flows of the spring systems. This 50-ft (15-m) distance defines the lateral extent of surface critical habitat that contains elements necessary to provide for life functions of this species with respect to roots that can penetrate into the aquifer. The 50-ft (15-m) distance was calculated from evaluations of aerial photographs and is based on tree and shrub canopies occurring in proximity to spring outlets. Extent of canopy cover reflects the approximate distances where plant root systems interface with water flows of the two spring systems. Critical habitat unit boundaries were delineated by creating approximate areas for the units by screen-digitizing polygons (map units) using ArcMap, version 10 (Environmental Systems Research Institute, Inc.) and 2011 aerial imagery.

Comal Springs Riffle Beetle

For the Comal Springs riffle beetle, we only identified surface critical habitat because this species' habitat is primarily restricted to surface water, which is located in two impounded spring systems in Comal and Hays Counties, Texas. In Comal County, this aquatic beetle is found in various spring outlets of Comal Springs that occur within Landa Lake over a linear distance of approximately 0.9 mi (1.4 km). The species has also been found in outlets of San Marcos Springs in the upstream portion of Spring Lake in Hays County. However, populations of Comal Springs riffle beetles may exist elsewhere in Spring Lake (excluding a slough portion that lacks spring outlets), but sampling for riffle beetles at spring outlets within the lake has only been done on a limited basis. Excluding the slough portion that lacks spring outlets, the approximate linear distance of Spring Lake at its greatest length is 0.2 mi (0.3 km). Critical habitat unit boundaries for surface area were delineated using the same criteria as described above for the Comal Springs dryopid beetle.

Peck's Cave Amphipod

We identified both surface and subsurface components of critical habitat for this species, which has been found in Comal Springs and Hueco Springs, both located in Comal County, Texas. The extent to which this subterranean species exists below ground away from spring outlets is unknown; however, other species within the genusStygobromusare widely distributed in groundwater and cave systems (Holsinger 1972, p. 65). Like the Comal Springs dryopid beetle, the Peck's cave amphipod has been collected from the bottom of Panther Canyon Well, which is located about 360 ft (110 m) away from the spring outlet of Spring Run No. 1 in the Comal Springs complex (Barr and Spangler 1992, p. 42; Gibsonet al.2008, p. 76). To determine surface critical habitat, we used a 50-ft (15-m) distance from the shoreline of both Comal Springs and Hueco Springs (including several satellite springs that are located between the main outlet of Hueco Springs and the Guadalupe River) to include amphipod food sources in the root-water interfaces around spring outlets. Critical habitat unit boundaries were delineated using the same criteria as described above for the other two invertebrate species.

The definition of critical habitat under the Act includes areas outside the geographical area occupied by the species at the time of listing, if those areas are found to be essential to the conservation of the species. In the case of the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod, the geographical area occupied by the species at the time of listing encompasses the known historic range of these species. As such, we have not found any areas outside the geographical areas occupied by these species at the time of their listing to be essential to the conservation of these species and, therefore, we are not proposing to designate any unoccupied areas as critical habitat.

When determining proposed critical habitat boundaries, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures on the surface that lack physical or biological features necessary for the Comal Springs dryopid beetle, Comal Springs riffle beetle and Peck's cave amphipod. Subterranean critical habitat for the Comal Springs dryopid beetle and Peck's cave amphipod may extend under such structures and remains part of the critical habitat. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed lands. Any such lands inadvertently left inside critical habitat boundaries shown on the maps of this proposed rule have been excluded by text in the proposed rule and are not proposed for designation as critical habitat. Therefore, if the critical habitat is finalized as proposed, a Federal action involving these lands would not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific action would affect the physical or biological features in the adjacent critical habitat.

We are proposing for designation of critical habitat lands that we have determined are occupied at the time of listing and contain sufficient elements of physical or biological features to support life-history processes essential for the conservation of the species.

Units were proposed for designation based on sufficient elements of physical or biological features being present to support Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod life-history processes. All units contain all of the identified elements of physical or biological features and support multiple life-history processes.

The critical habitat designation is defined by the map or maps, as modified by any accompanying regulatory text, presented at the end of this document in the rule portion. We include more detailed information on the boundaries of the critical habitat designation in the preamble of this document. We will make the coordinates or plot points or both on which each map is based available to the public onhttp://www.regulations.govat Docket No. FWS-R2-ES-2012-0082, on our Internet siteshttp://www.fws.gov/southwest/es/austintexas/, and at the field office responsible for the designation (seeFOR FURTHER INFORMATION CONTACTabove).

Summary of Changes From Previously Designated Critical Habitat

The areas identified in this proposed rule constitute a proposed revision of the areas we designated as critical habitat for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod on July 17, 2007 (72 FR 39248). The significant differences between the 2007 rule and this proposal are:

(1) In the 2007 critical habitat rule for these species, we did not designate subsurface critical habitat. However, we are designating subsurface critical habitat for the Comal Springs dryopid beetle and the Peck's cave amphipod in this rule.

(2) The amount of critical habitat is increasing in this proposed rule because (1) we are including subsurface habitat for the Comal Springs dryopid beetle and Peck's Cave amphipod, and (2) we are including the area 50 ft (15 m) from the shoreline for the Comal Springs riffle beetle.

(3) The primary constituent elements have been consolidated from five in the original critical habitat rule to three to better incorporate and define subsurface attributes.

Proposed Critical Habitat Designation

We are proposing four units as critical habitat for the three invertebrates. The critical habitat areas we describe below constitute our current best assessment of areas that meet the definition of critical habitat for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod. The four units we propose as critical habitat are: (1) Comal Springs, (2) Hueco Springs, (3) Fern Bank Springs, and (4) San Marcos Springs. Table 1 shows the occupied units, and Tables 2, 3, and 4 provide the approximate area of each proposed critical habitat unit for each species.

Table 1—Occupancy of Comal Springs Dryopid Beetle, Comal Spring Riffle Beetle, and Peck's Cave Amphipod by Proposed Critical Habitat Units Unit Occupied at time of listing? Currently
  • occupied?
  • Listed species in unit
    1. Comal Springs Yes Yes Comal Springs dryopid beetle, Comal Springs riffle beetle, and Pecks cave amphipod. 2. Hueco Springs Yes Yes Peck's cave amphipod. 3. Fern Bank Springs Yes Yes Comal Springs dryopid beetle. 4. San Marcos Springs Yes Yes Comal Springs riffle beetle.
    Table 2—Proposed Critical Habitat Units for the Comal Springs Dryopid Beetle. Area Estimates Reflect All Land Within Critical Habitat Unit Boundaries Critical habitat units for the Comal Springs Dryopid Beetle Land ownership by type Size of unit in acres (hectares) (subsurface critical habitat) Size of unit in acres (hectares) (surface critical habitat) 1. Comal Springs State, City, Private 124 (50) 38 (15) 2. Fern Bank Springs Private 15 (6) 1.4 (0.56) Total 139 (56) 39.4 (15.56) Note:Area sizes may not sum due to rounding. Table 3—Proposed Critical Habitat Units for the Comal Springs Riffle Beetle. Area Estimates Reflect All Land Within Critical Habitat Unit Boundaries Critical habitat units for the comal springs riffle beetle Land ownership by type Size of unit in acres (hectares) (surface critical habitat) 1. Comal Springs State, City, Private 38 (15) 2. San Marcos Springs State 16 (6) Total 54 (22) Note:Area sizes may not sum due to rounding. Table 4—Proposed Critical Habitat Units for the Peck's Cave Amphipod. Area Estimates Reflect All Land Within Critical Habitat Unit Boundaries Critical habitat units for the Peck's Cave amphipod Land ownership by type Size of unit in acres (hectares) (subsurface critical habitat) Size of unit in acres (hectares) (surface habitat) 1. Comal Springs State, City, Private 124 (50) 38 (15) 2. Hueco Springs Private 14 (6) 0.4 (0.16) Total 138 (56) 38.4 (15.16) Note:Area sizes may not sum due to rounding.

    We present brief descriptions of all units, and reasons why they meet the definition of critical habitat for the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod, below.

    Unit 1: Comal Springs Unit

    The purpose of this unit is to independently support a population of Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod in a functioning spring system with associated streams and underground spaces immediately inside of or adjacent to springs, seeps, and upwellings that provide suitable water quality, supply, and detritus (decomposed plant material).

    Unit 1 contains Comal Springs and consists of 124 ac (50 ha) of subsurface critical habitat for the Comal Springs dryopid beetle and the Peck's cave amphipod (Table 2 and 4). Unit 1 also contains 38 ac (15 ha) of surface habitat for these two species along with the Comal Springs riffle beetle (Table 3). This unit was occupied at the time of listing and is still occupied by the Comal Springs dryopid beetle, Comal Springs riffle beetle, and Peck's cave amphipod (Table 1).

    The