Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To Delist the Idaho Springsnail; 12-Month Finding on a Petition To List the Jackson Lake Springsnail, Harney Lake Springsnail, and Columbia Springsnail; and Proposed Rule To Remove the Idaho Springsnail From the List of Threatened and Endangered Wildlife, 56938-56948 [E6-15915]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 71, Number 188 (Thursday, September 28, 2006)]
[Proposed Rules]
[Pages 56938-56948]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-15915]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AU66


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To Delist the Idaho Springsnail; 12-Month Finding on a 
Petition To List the Jackson Lake Springsnail, Harney Lake Springsnail, 
and Columbia Springsnail; and Proposed Rule To Remove the Idaho 
Springsnail From the List of Threatened and Endangered Wildlife

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of two 12-month petition findings and a proposed rule to 
delist the Idaho springsnail (Pyrgulopsis idahoensis).

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SUMMARY: We, the U.S. Fish and Wildlife Service (USFWS, Service, or 
we), under the Endangered Species Act of 1973, as amended (Act), 
announce combined 12-month findings on a petition to delist the 
endangered Idaho springsnail (Pyrgulopsis idahoensis) and a petition to 
list the Jackson Lake springsnail (P. robusta), Harney Lake springsnail 
(P. hendersoni), and Columbia springsnail (P. species A (unnamed)). 
Evidence collected subsequent to the December 14, 1992, listing (USFWS 
1992, pp. 59244-59527 (57 FR 59244)) of the Idaho springsnail indicates 
it no longer constitutes a distinct species. It is now described as the 
Jackson Lake springsnail (P. robusta), a single taxon, composed of four 
previously distinct springsnail species (Idaho, Jackson Lake, Harney 
Lake, and Columbia springsnails), and therefore we are proposing to 
remove

[[Page 56939]]

the Idaho springsnail from the Federal List of Endangered and 
Threatened Wildlife. We evaluated the best available scientific and 
commercial information regarding the status of, and threats to, the 
newly described P. robusta, and determined that the threats to the 
species do not warrant its listing at this time. Additionally, based on 
our status review of P. robusta, we also find that listing the Jackson 
Lake springsnail, Harney Lake springsnail, and Columbia springsnail as 
separate species is not warranted.

DATES: The 12-month findings on the delisting and listing petitions 
announced in this notice were made on September 28, 2006. We request 
that new information be submitted to us concerning the status of, or 
threats to, Pyrgulopsis robusta, whenever it becomes available.
    We will accept comments from all interested parties regarding the 
proposal to delist the Idaho springsnail until November 27, 2006. We 
must receive requests for public hearings on or before November 13, 
2006.

ADDRESSES: Comments may be submitted on the proposed rule to delist the 
Idaho springsnail by any of the following methods. Please include RIN 
1018-AU66 in any subject line.
     E-mail: fws1srbocomments@fws.gov.
     Fax: (208) 378-5262.
     Hand carry, Postal Delivery, or Courier: Snake River Fish 
and Wildlife Office, U.S. Fish and Wildlife Service, 1387 S. Vinnell 
Way, Room 368, Boise, ID 83709.
     Federal Rulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments.
    Please see the Public Comments Solicited section below for file 
format and other information about electronic filing.

FOR FURTHER INFORMATION CONTACT: The Snake River Fish and Wildlife 
Office by mail at the above address; by telephone at 208/378-5243; by 
facsimile at 208/378-5262; or by electronic mail at: 
fw1srbocomment@fws.gov.

SUPPLEMENTARY INFORMATION:

Public Comments Solicited

    We intend that any final action resulting from this proposal will 
be as accurate and effective as possible. Therefore, comments or 
suggestions from the public, other concerned governmental agencies, 
Native American Tribes, the scientific community, industry, or any 
other interested party concerning this proposed rule are hereby 
solicited. Please note that comments merely stating support or 
opposition to the actions under consideration without providing 
supporting information, although noted, will not be considered in 
making a determination, because section 4(b)(1)(A) of the Act directs 
that determinations as to whether any species is a threatened or 
endangered species shall be made ``solely on the basis of the best 
scientific and commercial data available.''
    You may submit materials concerning this proposal by any one of 
several methods (see ADDRESSES section). Please submit Internet 
comments to fws1srbocomments@fws.gov in ASCII file format and avoid the 
use of special characters or any form of encryption. Please also 
include ``RIN 1018-AU66'' in your e-mail subject header and your name 
and return address in the body of your message. If you do not receive a 
confirmation from the system that we have received your Internet 
message, contact us directly (see ADDRESSES). Please note that the 
Internet address fws1srbocomments@fws.gov will be unavailable at the 
termination of the public comment period.
    Our practice is to make comments, including names and home 
addresses of respondents, available for public review during regular 
business hours. Individual respondents may request that we withhold 
their home addresses from the rulemaking record, which we will honor to 
the extent allowable by law. There also may be circumstances in which 
we would withhold from the rulemaking record a respondent's identity, 
as allowable by law. If you wish us to withhold your name and/or 
address, you must state this prominently at the beginning of your 
comment, but you should be aware that the Service may be required to 
disclose your name and address pursuant to the Freedom of Information 
Act. However, we will not consider anonymous comments. We will make all 
submissions from organizations or businesses, and from individuals 
identifying themselves as representatives or officials of organizations 
or businesses, available for public inspection in their entirety. 
Comments and other information received, as well as supporting 
information used to write this rule, will be available for public 
inspection, by appointment, during normal business hours at the above 
address. In making a final decision on this proposal, we will take into 
consideration any additional information we receive. Such 
communications may lead to a final regulation that differs from this 
proposal.

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.) requires that, for any petition 
to revise the List of Threatened and Endangered Species that contains 
substantial scientific and commercial information that suggests a 
change in status may be warranted, we make a finding within 12 months 
of the date of the receipt of the petition on whether the petitioned 
action is: (a) Not warranted; (b) warranted; or (c) warranted, but the 
immediate proposal of a regulation implementing the petitioned action 
is precluded by other pending proposals to determine whether a species 
is threatened or endangered, and expeditious progress is being made to 
add or remove qualified species from the List of Threatened and 
Endangered Species. Such 12-month findings are to be promptly published 
in the Federal Register. In addition, section 4(b)(3)(C) of the Act 
requires that a petition for which the requested action is found to be 
warranted but precluded shall be treated as though resubmitted on the 
date of such finding (i.e., requiring a subsequent finding to be made 
within 12 months).

Previous Federal Action

    We published the final rule listing the Idaho springsnail as 
endangered on December 14, 1992 (57 FR 59244). In that rule, we 
described range reduction, continued adverse habitat modification, 
deteriorating water quality from multiple sources, and the appearance 
of the invasive New Zealand mudsnail (Potamopyrgus antipodarum) as the 
major threats to the species. We have not designated critical habitat 
for the Idaho springsnail.
    On June 28, 2004, we received a petition from the Idaho Office of 
Species Conservation and the Idaho Power Company (IPC) requesting that 
the Idaho springsnail be delisted based on a recent taxonomic revision 
of the species. The petitioners also provided new Idaho springsnail 
scientific information, and contrasted this new information with 
information used in the 1992 Idaho springsnail listing decision (57 FR 
59244). The petitioners stated that most, if not all, threats to Idaho 
springsnail identified in the 1992 listing rule have been eliminated, 
are being actively addressed by State and private entities, or are not 
relevant, based on new scientific information.
    On August 5, 2004, we received a petition from Dr. Peter Bowler, 
the Biodiversity Conservation Alliance, the Center for Biological 
Diversity, the Center for Native Ecosystems, the

[[Page 56940]]

Western Watersheds Project, and the Xerces Society, requesting that the 
Jackson Lake springsnail, Harney Lake springsnail, and Columbia 
springsnail be listed as either threatened or endangered species, and 
as either individual species or combined as the new species, 
Pyrgulopsis robusta. This listing petition cited habitat loss and 
degradation from development impacting springs, domestic livestock 
grazing, and groundwater withdrawal, among other factors, as threats to 
the continued existence of these three springsnail species. The listing 
petition also discussed the recent springsnail taxonomic revision and 
acknowledged that the Jackson Lake springsnail, Harney Lake 
springsnail, Columbia springsnail, and Idaho springsnail may be one 
species (P. robusta), but contended that, whether considered 
individually or as one species, all four springsnails warranted the 
protection of the Act.
    On April 20, 2005, we published combined 90-day petition findings 
(USFWS 2005, pp. 20512-20514 (70 FR 20512)), stating that both 
petitions provided substantial information suggesting that delisting of 
the Idaho springsnail, or listing of Jackson Lake springsnail, Harney 
Lake springsnail, and Columbia springsnail, may be warranted.

Species Information

    The Idaho springsnail (Pyrgulopsis idahoensis; Hydrobiidae) was 
first described by Pilsbry (1933, pp. 11-12) and placed in the genus 
Amnicola. Greg and Taylor (1965, pp. 103-110) established the new genus 
Fontelicella and then placed P. idahoensis in the subgenus Natricola, 
created in 1965 (Greg and Taylor 1965, pp. 108-109). Natricola 
contained the Idaho springsnail, the Harney Lake springsnail (P. 
hendersoni), and the Jackson Lake springsnail (P. robusta). After 
several taxonomic revisions, the subgenus Natricola was placed in 
synonymy with the genus Pyrgulopsis by Hershler and Thompson (1987, p. 
29). Pyrgulopsis is the largest genus of freshwater mollusks in North 
America, comprised of over 120 described species (Liu and Hershler 
2005, p. 284). The greatest diversity of the genus occurs in the Great 
Basin of the western United States (Hershler and Sada 2000, p. 367; 
Hershler and Sada 2002, p. 255).
    In 2004, Hershler and Liu (2004, pp. 78-79) revised the taxonomic 
status of four springsnails Pyrgulopsis idahoensis, P. hendersoni, P. 
robusta, and the Columbia springsnail (P. species A (unnamed)), by 
placing all four springsnails into the oldest available taxon of the 
four revised species, P. robusta (Jackson Lake springsnail, Walker 
1908, p. 97). All four species were considered members of the subgenus 
Natricola. Members of the subgenus Natricola are very similar in size 
and shape, being distinguished primarily by the morphology of the 
shell. The authors reviewed morphological characters, mitochondrial DNA 
sequences, and nuclear DNA sequences to establish the need for 
taxonomic status change.
    Several morphological metrics, including the position of the callus 
(thickened portion) on the operculum (serves as a cover for the opening 
in the shell); the shape of the central cusp of the central teeth; the 
number of cusps on central teeth; notching of inner marginal teeth; 
number of cusps on outer marginal teeth; the male penile features; and 
female genitals, did not differ significantly among the four 
springsnail species (Hershler and Liu 2004, pp. 70-75). Five shell 
parameters were significantly heterogeneous in a comparison of the four 
springsnail species. In only one case did a single springsnail species 
differ significantly from the other three; the Idaho springsnail 
differed significantly from the other three springsnail species for the 
ratio of shell height to height of body whorl (Hershler and Liu 2004, 
p. 71).
    To construct species topologies, Hershler and Liu (2004, pp. 67-69) 
sequenced selected genes of four springsnail species, Pyrgulopsis 
robusta, P. idahoensis, P. hendersoni, and P. species A (unnamed), as 
well as congeners P. imperialis, P. intermedia, P. kolobensis, and P. 
species B (unnamed). The mitochondrial DNA data revealed little 
difference in the partial CO1 gene among the four springsnail species. 
Differences ranged from 0.0 to 0.8 percent (0 to 5 base pairs) among 
the four springsnail species and 2.6 to 6.9 percent (16 to 43 base 
pairs) with congeners. Nuclear DNA data revealed differences in the 
ITS-1 sequences within the four springsnail species that were 
substantially smaller (0.0 to 0.6 percent) than differences among other 
congeners (5.9 to 20.4 percent) (see Figure 8 in Hershler and Liu 2004, 
pp. 73-75). These two lines of evidence show that DNA sequence 
differences among the four springsnail species are very small compared 
to differences with other recognized taxa within the genus Pyrgulopsis.
    Hershler and Liu (2004, p. 77) concluded ``three independent data 
sets (morphology, mitochondrial, and nuclear DNA sequences) congruently 
suggest that these four Natricola snails do not merit recognition as 
distinct species according to various currently applied concepts of 
this taxonomic rank.'' The methods employed by Hershler and Liu (2004, 
pp. 67-70) are considered contemporary in the field of genetics and are 
consistent with those used by numerous authors reconstructing 
phylogenies based on molecular evidence in general (Raahauge and 
Kristensen 2000, pp. 87-89; Jones et al. 2001, pp. 281; Attwood et al. 
2003, pp. 265-266), and with western hydrobiid snails in particular 
(Hershler et al. 2003, pp. 358-359; Liu et al. 2003, pp. 2772-2775; 
Hurt 2004, pp. 1174-1177; Liu and Hershler 2005, p. 285). Further, it 
is the position of the American Malacological Society that the Hershler 
and Liu (2004) revised taxonomy sets the standard for understanding 
this group of springsnails (Leal 2004). Hershler and Liu (2004, pp. 66-
81) represents the best available scientific and commercial data on the 
taxonomic status of the four petitioned springsnails, and we therefore 
will refer to the four former springsnail species as Pyrgulopsis 
robusta for the rest of this document.

Biology

    Pyrgulopsis robusta shells are large for the genus, usually ovate 
(oval) to narrow-conic (cone shaped), rarely subglobose (not quite 
rounded), with whorls weakly to moderately convex (curving outward). 
The shell is clear-white and the periostracum (outer layer of the shell 
matrix) is tan. The aperture is ovate and weakly angled above. The 
inner lip is complete in larger specimens. The penial lobe and filament 
are about equal in length. The dorsal proximal lobule is well 
developed, usually overlapping the base of the filament and often borne 
on a weak proximal swelling. The terminal gland is elongate and 
transverse. The dorsal distal lobule is well developed and is usually 
bearing one or a series of small glands. The ventral lobule is well 
developed and bears a large gland (Hershler and Liu 2004, p. 79).
    Information available to describe the life history of Pyrgulopsis 
robusta varies widely. The species is hypothesized to primarily feed on 
periphyton (i.e., diatoms and algae), which covers the surface of most 
benthic (submerged bottom) substrates. Although little specific 
information exists regarding reproductive strategies of P. robusta, 
members of the genus Pyrgulopsis are generally dioecious (i.e., male 
and female individuals) (Dillon 2000, pp. 102-103; Lysne 2003, p. 80). 
Pyrgulopsis robusta is hypothesized to

[[Page 56941]]

reproduce once in an annual life cycle, and laboratory studies estimate 
average survival to be 382 days (Lysne 2003, p. 82). However, field 
data show that not all P. robusta die within a year (Finni 2003a, pp. 
3-5), a life history pattern suggested by Dillon (2000, p. 162) to be 
exhibited by many populations, allowing extended survivorship and 
multiple reproductive events. Additional P. robusta life history 
information regarding reproduction and growth rates can be found in the 
following references: Finni 2003a, pp. 3-5; Lysne 2003, pp. 24, 36, 38, 
79-81; Riley et al. 2003, p. 33; Dillon 2000, p. 103; and, Hershler 
1994, pp. 1-119.

Habitat

    Species in the genus Pyrgulopsis require permanent fresh waters 
(Taylor 1985, pp. 265, 276; Hershler 1998, p. 1; Hershler and Sada 
2002, p. 255). Pyrgulopsis robusta utilizes a wide range of flow 
conditions and habitats. For example, P. robusta has been found in the 
mainstem Snake River, Idaho, in various habitats; in C.J. Strike and 
Swan Falls Reservoirs, Idaho (Clark 2005); and in two springs that flow 
through Yellowstone National Park and John D. Rockefeller National 
Parkway in Wyoming: Marmot Spring, a relatively stable groundwater-fed 
spring, and Polecat Creek, a geothermal spring (Riley 2005a, pp. 1, 8; 
Hall et al. 2003, p. 408). In southeastern Oregon, P. robusta primarily 
occurs in cold springs and spring pools of variable size (Frest and 
Johannes 1995, p. 196), but is also found in the South Fork Malheur 
River (Hershler and Liu 2004, p. 67). Although P. robusta evolved in 
prehistoric Lake Idaho (Taylor 1982, p. 2; Taylor 1985, pp. 288, 309), 
the species presently occurs more frequently and abundantly in river 
habitat than in lake or reservoir habitat (Clark 2005).
    Pyrgulopsis robusta is found on a wide range of substrates in the 
Snake and Columbia Rivers, from silt and pebbles to cobbles and 
boulders, but in the Snake River the species achieves highest density 
on gravel to cobble substrates (Stephenson et al. 2004, A3 pp. 1-4, A4 
pp. 1-4). In Southeastern Oregon, the species is generally found on 
coarse sand to cobble substrates but may also be associated with the 
submerged aquatic plant genus Rorippa (Frest and Johannes 1995, p. 
196).
    Field and laboratory information indicate Pyrgulopsis robusta has a 
wide temperature tolerance (Stephenson and Bean 2003, pp. A1, A2; 
Stephenson et al. 2004, A3 pp. 1-4, A4 pp. 1-4; Lysne 2003, p. 27). 
Pyrgulopsis robusta has been documented to survive and grow at 
temperatures that exceeded the State of Idaho's water temperature 
criteria for cold-water life of 66 degrees Fahrenheit (F) (19 degrees 
Celsius (C)) mean daily and 72 degrees F (22 degrees C) maximum daily 
water temperatures (Lysne 2003, pp. 27-29). Pyrgulopsis robusta have 
been routinely collected in the Snake River at water temperatures 
greater than 68 degrees F (20 degrees C) (Stephenson and Bean 2003, pp. 
A1, A2; Stephenson et al. 2004, A3 pp. 1-4, A4 pp. 1-4). In Wyoming, 
high numbers of P. robusta have been collected in Polecat Creek, a 
geothermal spring creek with temperatures ranging from approximately 
57.2 degrees F (14 degrees C) in winter to 75.2 degrees F (24 degrees 
C) in summer (Hall et al. 2003, p. 408). Other variables that 
potentially influence P. robusta habitat selection and use have not 
been well documented.

Range and Distribution

    Pyrgulopsis robusta is now comprised of four geographically 
isolated populations that include the northwestern Wyoming population, 
the Snake River population in Idaho, the Columbia River population in 
Oregon and Washington, and the Oregon closed-basin population (Hershler 
1994, p. 91; Hershler 1998, p. 99; Riley et al. 2003, p. 6; Frest 
2005a; Riley 2005b). In Wyoming, P. robusta is currently known from 
only two locations in Yellowstone National Park and John D. Rockefeller 
National Parkway. There have been past collections at other sites, and 
P. robusta may be found at additional locations in the future. Recent 
surveys have failed to locate the species in Jackson Lake (Riley 
2005b), the type locality of P. robusta as described by Walker in 1908.
    In southeastern Oregon, Pyrgulopsis robusta occurs in few locations 
(six or fewer) in the Oregon Interior Basin, in isolated cold springs 
and spring pools (Frest and Johannes 1995, p. 196), and in the South 
Fork Malheur River, a tributary to the Snake River (Hershler and Liu 
2004, p. 67), in Harney and Lake Counties. Pyrgulopsis robusta was 
historically found along the shores of Malheur and Harney Lakes (Frest 
and Johannes 1995, p. 196) and was associated with open water habitats 
(as opposed to wetland habitats with emergent vegetation) 8,000 to 
10,000 years ago (Wriston 2003, p. 28). Pyrgulopsis robusta is not 
known to currently exist in Harney or Malheur Lakes, and it is 
uncertain when P. robusta last existed there (Frest and Johannes 1995, 
p. 196). Many isolated springs and other aquatic habitats of Utah, 
Nevada, and Idaho in the Great Basin, including parts of southeastern 
Oregon, have been surveyed specifically for springsnails, but no 
additional P. robusta have been located (Hershler 1998, p. 3; Hershler 
and Sada 2002, p. 259).
    In the Snake River, Pyrgulopsis robusta is known to occur at 
numerous locations along a stretch of 214 river miles (344 kilometer 
(km)) between river mile (rm) 340 (river kilometer mile (rkm) 547) and 
rm 554 (rkm 892). There have been at least 174 collections from this 
reach of river and the extent of P. robusta is believed to be well 
defined and relatively abundant. The distribution of P. robusta in the 
Columbia River is less well known than in the Snake River, particularly 
in the Hanford Reach below Priest Rapids Dam. In the Columbia River, P. 
robusta is known from 17 locations, beginning at approximately rm 20 
(rkm 32) and continuing for nearly 400 miles (649 km) upstream to just 
below Priest Rapids Dam (Frest 2005a). Although there have been several 
hundred invertebrate samples collected in the Columbia River over the 
past several years, P. robusta has been found only in a few of these 
samples (Frest 2005a).

Status Review Process

    On April 20, 2005, we initiated combined 12-month status reviews 
(70 FR 20512) of the petitioned springsnails, as well as a 5-year 
review of the Idaho springsnail under section 4(c)(2)(A) of the Act, 
and solicited additional information from the public on the biology, 
ecology, distribution and status, threats affecting the petitioned 
springsnail species, and any ongoing or planned conservation measures.
    During the 60-day public comment period, we contacted numerous 
Federal and State resource agencies, interested Tribal governments, and 
County governments. On June 7, 2005, we attended an information 
exchange meeting with the State of Idaho Office of Species 
Conservation, Idaho Department of Fish and Game (IDFG), Idaho 
Department of Environmental Quality (IDEQ), U.S. Bureau of Reclamation 
(BOR), U.S. Bureau of Land Management (BLM), and others. After this 
information exchange meeting, our staff assimilated and analyzed all 
the new information submitted during the 60-day public comment period, 
along with the existing information already obtained from published 
scientific literature, unpublished technical documents, and written and 
personal communications. As part of our routine Status Review process, 
we took this synthesized information and created a document titled: 
Draft Best Available Biological Information for Four Petitioned 
Springsnail Species from

[[Page 56942]]

Idaho, Oregon, Washington, and Wyoming (Draft BAI). The Draft BAI 
represented our comprehensive, best available scientific and commercial 
information on the petitioned springsnails.
    On August 3, 2005, through a widely distributed outreach effort 
that included a news release, Dear Interested Party letter, posting on 
the Service's Web site, and a request for peer review, we opened an 
additional 30-day public and peer review comment period on the Draft 
BAI. After the public and peer review, Service staff incorporated the 
additional information and technical corrections received, and wrote 
Version 2.0 Best Available Biological Information for Four Petitioned 
Springsnail Species from Idaho, Oregon, Washington, and Wyoming (BAI). 
The revised BAI constituted the peer-reviewed state of knowledge with 
regard to the taxonomy, biology, ecology, distribution, and status of 
the four petitioned springsnail species, now combined as Pyrgulopsis 
robusta, and was used throughout the remainder of the Status Review 
process as the primary source of best available scientific and 
commercial data.
    The Service utilized a structured decision making model to assess 
the available data. Based on an early assessment of the degree of 
uncertainty surrounding the population trends and conservation status 
of Pyrgulopsis robusta, the Service used two panels to inform our 
recommended course. The first panel (Expert Panel) was made up of six 
scientists from outside the Service with expertise in relevant fields, 
including snail biology and ecology, community ecology, population 
ecology, stream ecology, aquatic ecotoxicology, and regional water 
quality. This Expert Panel met on October 18-19, 2005, to discuss the 
strengths and weaknesses of the various data, hypotheses, and opinions 
relative to the current status of P. robusta. The Expert Panel only 
addressed the scientific aspects of risk and threats, and estimated the 
probable extinction risk to P. robusta. A second ``Managers Panel'' of 
five Service managers and senior biologists met on October 20-21, 2005, 
to consider the Expert Panel's input and all other information 
necessary to conduct an extinction risk assessment of P. robusta. 
Information generated from these two Panels was used in the Service's 
status review to assess threats to, and evaluate the listing status of, 
P. robusta. Further details about the structured decision making 
process used by the two panels are documented in our administrative 
record for this proposed rule.
    Inspection of the petition to delist the Idaho springsnail, the 
petition to list the Jackson Lake, Harney Lake, and Columbia 
springsnails, and the supporting information, administrative finding, 
and other relevant materials may be made in person, by appointment, at 
the address listed above (see ADDRESSES).

Summary of Factors Affecting the Species

    Section 4 of the Act and regulations (50 CFR Part 424) promulgated 
to implement the listing provisions of the Act set forth the procedures 
for listing, reclassifying, and delisting species. A species may be 
listed as threatened or endangered if one or more of the five factors 
described in section 4(a)(1) of the Act threaten the continued 
existence of the species. A species may be delisted, according to 50 
CFR 424.11(d), if the best scientific and commercial data available 
substantiate that the species is neither endangered nor threatened 
because of: (1) Extinction; (2) recovery; or (3) error in the original 
data, or the data analysis, used for classification of the species. For 
species that are being considered for delisting, the analysis of 
threats must include an evaluation of threats that existed at the time 
of listing and those that currently exist or that could, with a 
reasonable degree of likelihood, potentially affect the species in the 
foreseeable future after its delisting and the consequent removal of 
the Act's protections.

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

    The 1992 final listing rule (57 FR 59244) described activities such 
as proposed large hydroelectric dam developments, peak-loading 
operations of existing hydroelectric water projects, small 
hydroelectric developments, water pollution, and water diversions whose 
cumulative effects threatened the habitat and fragmented populations of 
the Idaho springsnail (Pyrgulopsis idahoensis). After reviewing the 
best available scientific and commercial information regarding present 
or threatened destruction, modification, or curtailment of the habitat 
or range of P. robusta, we determined that the principal habitat-
related threats are not proceeding at a rate that will threaten the 
continued existence of the species within the foreseeable future.
Dams and Reservoirs
    Our 1992 listing of the Idaho springsnail was based on information 
that indicated that the species was found only in permanent flowing 
waters of the mainstem Snake River, and that its historic range had 
been reduced nearly 80 percent, in large part by dam and reservoir 
development and operations.
    Populations of Pyrgulopsis robusta have been collected from various 
habitats, including springs, river reaches, and both lake and reservoir 
locations (Bickell 1977, p. 33; Hershler 1998, p. 99; Richards and 
Lester 2002, pp. 6-7; Stephenson et al. 2004, pp. 11, 21). In the Snake 
River in Idaho, where P. robusta occurs over a range of 214 river miles 
(344 km), the greatest number of live collections and the highest 
percentages of P. robusta occurrence are generally found in flowing 
waters influenced by reservoirs (Clark 2005). While extensive surveys 
conducted in downstream reaches (i.e., below Hells Canyon) of the Snake 
River (Shinn et al. 2001, pp. 80-82; Finni 2003b, p. 1; Richards et al. 
2005, pp. 4-5) and Columbia River basins (Frest and Johannes 1995, p. 
203) have not documented the presence of springsnails, springsnails 
have been known to persist in habitats associated with reservoirs 
(i.e., C.J. Strike and Swan Falls). At the upstream end of their range 
in C.J. Strike Reservoir, abundant numbers of springsnails are located 
at the mouth of a small tributary (i.e., main-pool) and on the gravel 
shores of the Bruneau River Arm, where comparatively cool and flowing 
waters (i.e., relative to the Snake River) of the Bruneau River run 
into C.J. Strike Reservoir (Stephenson et al. 2004, p. 21). In Swan 
Falls Reservoir, P. robusta are found in the headwaters (i.e., the 
nebulous upstream end of a reservoir and downstream end of free-flowing 
river) of the reservoir, but only one snail has been collected (at rm 
460; rkm 740) in the main pool from the dam to 7 miles (11.2 km) 
upstream of the dam (Clark 2005).
    At the downstream end of Pyrgulopsis robusta's range in Idaho, the 
species' known distribution ends immediately above the Hells Canyon 
Complex at the headwaters of Brownlee Reservoir (approximately rm 340 
(rkm 547)). The Hells Canyon Complex includes three large reservoirs 
(Brownlee, Oxbow, and Hells Canyon) that are deep (two have very steep 
sides) and whose waters fluctuate on both a daily and annual basis 
(Esch 2005). Surveys by the IPC in and below the Hells Canyon Complex 
have not yielded P. robusta (Finni 2003b, pp. 9, 19; Meyers and Foster 
2003, pp. 17-18; Richards et al. 2005, pp. 71-78, 103-149). The 
particular habitat conditions of these reservoirs may not be able to 
support P. robusta and may also prevent successful

[[Page 56943]]

downstream migration to suitable habitat below the Hells Canyon Complex 
(Shinn et al., 2001, p. 20; Meyers and Foster 2003, pp. 18-20).
    In Oregon and Washington, Pyrgulopsis robusta has been documented 
in the lower Columbia River below Dalles and John Day Dams and in their 
pools (Frest 2005a). These collections were in areas where the flow is 
greater and the river is shallower than in the reservoir (Frest 2005a). 
In southeastern Oregon, P. robusta was found in the south fork of the 
Malheur River (Hershler and Liu 2004, p. 79; Frest 2005a). These 
collections were reported to have been taken 60 miles upstream of Warm 
Springs Dam in an area of spring up-welling from the hyporheic zone 
(area below the streambed where water passes through spaces between the 
rock and cobble) (Frest 2005a, b).
    Our current status review indicates that Pyrgulopsis robusta is not 
restricted to permanent free-flowing water; the species also occurs in 
slower moving reservoir reaches and also in areas with and without 
spring inflow or upwelling occurrences. Our previous concern, as stated 
in the 1992 listing rule, regarding the historic range of the species 
in the Snake River having been reduced nearly 80 percent by dams and 
reservoirs, does not apply to P. robusta. New information collected on 
the Idaho springsnail population's life history, distribution, and 
status has been incorporated into this status review, together with 
information about the three other P. robusta populations (Jackson Lake, 
Harney Lake, and Columbia River). Much of this information has been 
collected during aquatic and mollusk surveys conducted by the IPC in 
the Snake River and Frest (2005 a, b) for the Columbia River and 
southeast Oregon populations. The IPC has been collecting information 
on Idaho springsnail populations throughout the Snake River since 1995. 
Based on the results of these surveys and laboratory studies, we now 
have a much better understanding of the basic life history as well as 
current distribution and status of P. robusta in the Snake River. These 
surveys have documented that P. robusta is more widely distributed in 
the Snake River than originally described in the 1992 listing rule. IPC 
biologists have surveyed over 400 river miles (644 km) in the Snake 
River and have documented the species at over 174 known locations over 
214 river miles (344 km), between rm 340 (rkm 547) and rm 554 (rkm 892) 
(Clark 2005), a nearly 500 percent increase, or 179 river miles (292 
km), of its known range. In summary, P. robusta has been determined to 
be more widely distributed and to occur on a much wider diversity of 
substrate types and sizes, and in a greater variety of aquatic habitats 
than was known at the time of the Idaho springsnail's listing in 1992. 
The species occurs throughout long reaches of the Snake River and 
Columbia Rivers in areas that are influenced by dams and reservoirs.
    The 1992 listing rule discussed ``peak-loading, the practice of 
artificially raising and lowering river levels to meet short-term 
electrical needs by local run-of-the-river hydroelectric projects,'' as 
a threat that ``may adversely affect three known populations of the 
Idaho springsnail'' (57 FR 59252). Certain hydroelectric power 
generating operational scenarios (e.g., water storage, diversion, and 
peak-loading) have been documented to have adverse impacts on aquatic 
communities (Armitage 1984, pp. 141-143; Brusven 1984, p. 167; Vaughn 
and Taylor 1999, pp. 915-916; Watters 2000, p. 1). C.J. Strike Dam is 
the primary peak-loading hydroelectric facility in the Snake River, yet 
Pyrgulopsis robusta persists in the peak-loading-affected area (Clark 
2005). For example, the largest monitored colony of P. robusta exists 
in the Snake River approximately 3 river miles (4.8 km) downstream of 
C.J. Strike Dam (Stephenson et al. 2004, p. 14). The Expert Panel and 
Service's Manager Panel both acknowledged that because colonies of P. 
robusta are widespread and known to occur over a 214-mile (344-km) 
stretch of the Snake River that is subject to long-term, recurring 
peak-loading and fluctuating flows, these colonies are resilient and 
will likely continue to persist into the foreseeable future.
    The effects of dams and reservoirs have been suggested as barriers 
to dispersal for Pyrgulopsis robusta. Species that have limited 
distributions and/or smaller, isolated populations may have a higher 
risk of local extirpations due to various threats and demographic 
stochasticity (variability) (Meffe et al. 1997, pp. 284-299; Vaughn and 
Taylor 1999, p. 916; Fagan et al. 2002, p. 3250). Both the Expert 
Panelists and Service's Manager Panelists acknowledged this risk for 
springsnails, but did not expect these populations to become extirpated 
due to possible barriers to dispersal in the foreseeable future.
Groundwater Pumping
    Groundwater pumping is only a concern for Pyrgulopsis robusta 
populations in southeast Oregon. Groundwater pumping for domestic use, 
agriculture, and industry may deplete flows from groundwater-fed spring 
systems by altering, modifying, or curtailing habitats dependent on 
those groundwater sources (Sada and Vinyard 2002, pp. 277-278).
    The Oregon Water Resources Department (OWRD) regulates water 
development (OWRD 2005a), but very little information is available for 
the Malheur Basin or the Abert Lake Basin, where the Harney Lake 
population of Pyrgulopsis robusta is found. While spring development 
and/or destruction have been implicated in native species declines in 
southeastern Oregon (Frest and Johannes 1995, p. 196), we are not aware 
of spring alterations, modifications, or conservation efforts that are 
affecting P. robusta in southeastern Oregon. Although at least one 
location previously containing P. robusta in southeastern Oregon no 
longer has springsnails (Hershler 1994, p. 41; Frest and Johannes 1995, 
p. 196), groundwater pumping can not be explicitly linked to the 
springsnail's absence. In two OWRD observation wells in the Malheur 
Basin, groundwater levels seem to have been relatively stable since 
1960 (OWRD 2005b). We acknowledge that diversion of springwater flows 
and groundwater pumping can represent barriers to dispersal and 
potentially isolate populations of P. robusta. However, these effects 
are limited to populations only in southeast Oregon, and not elsewhere 
in the species' range.
Water Quality--Temperature, Nutrients, and Chemical Stressors
    The 1992 listing rule (57 FR 59244) stated, ``The quality of water 
in these habitats has a direct effect on the species survival. The 
species requires cold, well-oxygenated unpolluted water for survival. 
Any factor that leads to a deterioration in water quality would likely 
extirpate these taxa.''
    Numerous reaches of the Snake and Columbia Rivers are classified as 
water-quality-impaired due to the presence of one or more pollutants 
(e.g., total phosphorous, sediments, total coliforms) in excess of 
State or Federal guidelines. Nutrient-enriched waters primarily enter 
the Snake and Columbia Rivers via springs, tributaries, fish farm 
effluents, municipal waste treatment facilities, and irrigation returns 
(U.S. Environmental Protection Agency (USEPA) 2002, pp. 4-20 to 4-22; 
USFWS 2004, p. 1; U.S. Geological Survey (USGS) 2005, p. 5). Irrigation 
water returned to rivers is generally warmer, contains pesticides or 
pesticide byproducts, has been enriched with nutrients from agriculture 
(e.g., nitrogen

[[Page 56944]]

and phosphorous), and frequently contains elevated sediment loads. 
Pollutants in fish farm effluent include nutrients derived from 
metabolic wastes of the fish and unconsumed fish food, disinfectants, 
bacteria, and residual quantities of drugs used to control disease 
outbreaks. Recent research found elevated levels of fine sediments and 
nitrogen as well as elevated levels of trace elements, including zinc, 
copper, cadmium, lead, and chromium, immediately downstream of 
aquaculture discharges (Falter and Hinson 2003, p. 53). Additionally, 
concentrations of lead, cadmium, and arsenic were detected in snails 
collected during a research study in the Snake River (Richards 2002). 
Researchers at the USGS (1998, p. 15) detected concentrations of some 
pesticides in fish tissues, streams, irrigation canals, and irrigation 
returns in the Snake River Basin in concentrations exceeding the 
aquatic-life criteria established by the USEPA. While some effects of 
pollutants, including metals and organic compounds in stream organisms, 
are documented in the literature (Naimo 1995, pp. 351-352; Clements 
1999, pp. 1076-1078; Courtney and Clements 2002, pp. 1770-1773), the 
potential impact of these contaminants on Pyrgulopsis robusta has not 
been studied and is unknown. However, P. robusta has been documented to 
occur downstream in these stretches of the Snake River where municipal, 
aquaculture, and agricultural discharges occur.
    In the upper Snake River Basin in Wyoming, very low levels of 
ammonia, nitrite and nitrate, phosphorus, trace metals, and pesticides 
have been detected in water quality assessments (USGS 2004, p. 39). 
Polecat Creek, which contains Pyrgulopsis robusta (Riley et al. 2003, 
p. 6), was included in Wyoming's section 303(d) of the Clean Water Act 
list of impaired waterbodies due to fecal coliform contamination (WDEQ 
2004, pp. 1-91). However, water quality in the upper Snake River Basin 
in Wyoming is generally described as good (USGS 2004, p. 38).
    Changes in a river's flow and depth as a result of dams lead to 
changes in sediment deposition dynamics and thermal characteristics 
(Poff et al. 1997, p. 773; Platts 1992, p. 2). Water-transported 
sediments that would be flushed downstream and deposited in pools, 
eddies, and other still water environments under normal river flows now 
settle in slow moving reservoir waters (Poff et al. 1997, p. 773; 
Simons 1979, pp. 96, 100-104). Additionally, drops in water velocity in 
reservoirs may result in elevated surface water temperatures and 
reductions in dissolved oxygen (USGS 2005, p. 11). Pyrgulopsis robusta 
has adapted to, and survives in, a relatively wide range of 
temperatures within the Snake River (Lysne 2003, p. 27). The IPC has 
collected P. robusta in water temperatures ranging from near freezing 
to 80 degrees F (27 degrees C) (Clark 2005). While high temperatures 
may be of concern for some aquatic snail species, we are not aware that 
water temperature limits growth, reproduction, or survival of P. 
robusta in any portion of its range. Pyrgulopsis robusta is widespread 
and abundant, occurring in a variety of water quality, flow, and 
temperature ranges. Expert and Manager Panels noted that water quality 
has not significantly modified or curtailed the habitat or range of P. 
robusta to an extent that threatens the continued existence of the 
species.
Grazing
    Grazing by cattle has been suggested to be a threat to Pyrgulopsis 
robusta habitat in southeastern Oregon (Frest and Johannes 1995, p. 
196), but not in other areas. However, little information exists 
regarding the impact of livestock grazing on the P. robusta in 
southeastern Oregon. Since the mid 1980s, cattle have been excluded 
from riparian areas, springs, and spring creeks in both the Harney and 
Malheur Lakes region (Burnside 2004). The Expert and Manager panels 
agreed that grazing does not appear to constitute a threat to the 
continued existence of the species since it is limited only to portions 
of the southeastern Oregon populations.
Summary of Factor A
    In summary, Pyrgulopsis robusta is distributed over a wide 
geographic area and a wide range of aquatic habitats in Idaho, Oregon, 
Washington, and Wyoming. Based on new information, previous concerns 
about the species being restricted to permanent free flowing water and 
a reduction in range limiting its distribution or threatening its 
existence are no longer valid. For example, since the 1992 listing, P. 
robusta in the Snake River has been collected at 174 locations over 214 
river miles (342 km). We are not aware that water temperature limits 
growth, reproduction, or survival of P. robusta in any portion of its 
range. Dam-induced changes to large river habitats in the Snake River 
or Columbia River may create conditions that likely represent barriers 
to P. robusta migration; however, the species persists throughout long 
reaches of these two river systems in areas influenced by dams and 
hydroelectric operations. Barriers to dispersal (i.e., isolated and 
fragmented populations) were considered a threat factor by the Expert 
Panel for the southeastern Oregon populations, but were considered 
relatively insignificant in both the Snake and Columbia Rivers. The 
fact that P. robusta is often locally abundant, resilient, and 
adaptable to a range of extrinsic factors, contributes to the 
determination that P. robusta is not in danger of extinction within the 
foreseeable future. Thus, based on the best scientific and commercial 
data, we conclude that the present or threatened destruction, 
modification, or curtailment of P. robusta's habitat or range is not a 
factor that threatens or endangers the species throughout all or a 
significant portion of its range.

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

    Overutilization of Pyrgulopsis robusta for commercial, 
recreational, or scientific purposes was not considered to be an 
applicable threat at the time of the 1992 listing (57 FR 59242), and is 
still not considered by the Expert Panel and Service's Manager Panel to 
be a threat to P. robusta throughout all or a significant portion of 
its range.

C. Disease or Predation

    We have no information on the actual effects of disease or 
parasites on Pyrgulopsis robusta.
    At the time of the 1992 listing, fish predation was not considered 
to be a major threat (57 FR 59242). There is currently no information 
regarding the threat of predation on the continued existence of 
Pyrgulopsis robusta. Predation on snails, in general, is documented and 
is a natural occurrence (Merrick et al. 1992, p. 231; McCarthy and 
Fisher 2000, p. 387), but information on the effects of predation on P. 
robusta is limited. In the only known account of predation by fish on 
P. robusta, Beetle (1957, p. 17) reported shells were found in the 
digestive tract of a Roseyside sucker (Catostomus fecundus) near 
Jackson Lake Dam, Wyoming. A recent study of predation ecology with 
Pyrgulopsis species failed to observe predation by native crayfish 
(Pacifasticus spp.) (Lysne and Koetsier 2001, p. 6).
    The Expert Panel did not identify disease or predation as a 
significant threat, but information is lacking to draw any definitive 
conclusions about risks to Pyrgulopsis robusta due to predation. Based 
on the best scientific and commercial data available, we conclude that 
disease and predation are

[[Page 56945]]

not factors that endanger or threaten P. robusta throughout all or a 
significant portion of its range.

D. The Inadequacy of Existing Regulatory Mechanisms

    In the 1992 Idaho springsnail listing rule (57 FR 59244), nutrient 
loading and pollution in the middle Snake River were identified as 
areas of concern. We stated that it was unlikely that the downward 
trend in water quality would be reversed any time soon, because it 
would take several years before any recommendations to improve water 
quality, as outlined in comprehensive resource management plans for the 
Snake River, were fully implemented through local, State, and Federal 
programs and efforts. However, since the 1992 listing rule, some water 
quality improvements have been realized in localized reaches of the 
Snake River, primarily with regard to sediment and phosphorus reduction 
(Buhidar 2005). These improvements are more fully discussed in the 
Water Quality Management section below.
    Based on our status review, we describe various regulatory 
mechanisms implemented by State and Federal resource agencies to 
protect Pyrgulopsis robusta and its habitat. Federal agency regulations 
are generally consistent across States, but State regulations may 
differ considerably with regard to similar natural resource issues. 
Analogous State natural resource agencies exist in Idaho, Oregon, 
Washington, and Wyoming.
Wildlife Conservation Statutes and Plans
    Washington has the comprehensive statutory authority and mandate to 
``preserve and protect'' all wildlife, including invertebrates such as 
Pyrgulopsis robusta, within its borders (Revised Code of Washington 
77.04.012). The Idaho Department of Fish and Game (IDFG) developed a 
Comprehensive Wildlife Conservation Strategy (Idaho Strategy) that 
lists P. robusta as a ``species of greatest conservation need'' (IDFG 
2005, p. 413). For example, Pyrgulopsis robusta conservation will be 
considered when IDFG engages other States, Federal agencies, and other 
conservation partners on proposed activities affecting Snake River 
habitats (e.g., boat ramp construction). The Idaho Natural Heritage 
Program lists Idaho springsnail as a species of concern, the Oregon 
Natural Heritage Program lists Columbia and Harney Lake springsnails as 
species of concern (ODFW 2005, p. 354), and in Wyoming, the Jackson 
Lake springsnail is also listed as a species of concern (WGFD 2005, p. 
15). These State wildlife conservation strategies and plans are useful 
to land managers because they provide the best available information 
for species of greatest conservation need and allow these managers to 
make informed decisions about land use changes.
Water Quality Management
    There are various State-managed water quality programs within the 
range of Pyrgulopsis robusta in Idaho, Washington, Wyoming, and Oregon. 
These programs are tiered off of the Clean Water Act (CWA), which 
requires States to establish water quality standards that provide for 
the protection and propagation of fish, shellfish, and wildlife, and 
recreation in and on the water (``fishable/swimmable''). In addition, 
as part of the CWA, States must also include an antidegradation policy 
that protects waterbody uses, and high-quality waters. In Idaho, 
Washington, Wyoming, and Oregon, point source discharges are regulated 
through the National Pollutant Discharge Elimination System (NPDES) 
program. These NPDES permits are written to meet all applicable water 
quality standards established for a waterbody to protect human health 
and aquatic life.
    Idaho has established water quality standards (e.g., water 
temperature and dissolved oxygen) for the protections of cold-water 
biota (e.g., invertebrate species) in many reaches of the Snake River. 
Although conditions within the river periodically exceed these limits 
during the summer months (USGS 2005, pp. 7-12), Pyrgulopsis robusta has 
been collected in water temperatures ranging from near freezing to 80 
degrees F (27 degrees C) (Clark 2005). While high temperatures may be 
of concern for some aquatic snail species, water temperature does not 
seem to limit growth, reproduction, or survival of P. robusta in any 
portion of its range.
    Waters that do not meet standards due to point- and non-point 
source pollution are listed on USEPA's 303(d) list of impaired water 
bodies. States must submit to USEPA a 303(d) list (water quality-
limited waters) and a 305(b) report (status of the State's waters) 
every two years. Water quality improvements with regard to point and 
non-point sources have been realized in localized reaches of the Snake 
River where P. robusta occurs (Buhidar 2005), primarily with regard to 
sediment and phosphorus criteria. The IDEQ, under authority of the 
State Nutrient Management Act, is coordinating efforts to identify and 
quantify contributing sources of pollutants (including nutrient and 
sediment loading) to the Snake River basin via the Total Maximum Daily 
Load (TMDL) approach. TMDLs are developed, adopted, and implemented 
within State Agricultural Water Quality Program, CWA section 401 
Certification, BLM Resource Management Plans, the State Water Plan, and 
local ordinances.
    In Oregon, point- and non-point source pollution is managed by 
Oregon's Department of Environmental Quality (ODEQ). TMDLs for several 
stream reaches are in development for the Malheur River Basin where 
Pyrgulopsis robusta exists. TMDLs establish mechanisms to address point 
and non-point sources to bring these reaches into compliance with water 
quality standards.
    In Washington, the State's Department of Ecology (WECY) has a 
mandate to manage point and non-point sources of pollution entering 
Washington's waters (WECY 2005). Non-point sources of pollution are 
regulated by numerous State of Washington statutes (WECY 2005), and 
managed primarily through Washington's Water Quality Management Plan to 
Control Non-point Source Pollution (Plan), published in 2000. 
Pyrgulopsis robusta is found in the Columbia River, and the Plan may 
indirectly benefit the springsnails that occur there.
    In Wyoming, Pyrgulopsis robusta exists within waters that occur in 
National Parks and are designated as Class 1 or ``outstanding waters'' 
by the Wyoming Department of Environmental Quality. Maintaining this 
designation is one of the National Park Service's highest priorities 
(USGS 2004, p. 2). We are not aware of any proposals to modify these 
designations or of activities that would impair these water bodies.
Federal Land Management
    Many large scale Federal management plans (e.g., U.S. Forest 
Service Land and Resource Management Plans, U.S. Bureau of Land 
Management (BLM) Resource Management Plans, National Wildlife Refuge 
Comprehensive Conservation Plans, and Interior Columbia Basin Ecosystem 
Management Plan) promote conservation of aquatic and terrestrial 
habitats, including those on which Pyrgulopsis robusta depends.
    Much of the Federal lands adjacent to the Snake River in Wyoming, 
Idaho, Oregon, and Washington are managed by the BLM. Resource 
Management Plans (RMPs) that guide BLM resource management include 
provisions to protect water quality and riparian habitats. The Service 
and the BLM in Idaho have finalized a Conservation

[[Page 56946]]

Agreement (USBLM 2006, pp. 1-11) that commits the BLM to carry out 
specific actions to assess status and distribution of P. robusta in 
areas affected by management actions and also to modify those actions 
to avoid and minimize impacts to the species in the Snake River. In 
addition, BLM has completed Endangered Species Act section 7 
consultations for some actions that may affect P. idahoensis, now known 
as P. robusta. The BLM's Boise and Twin Falls Districts have completed 
a joint section 7 consultation for ongoing livestock grazing activities 
in allotments adjacent to P. robusta habitats in the Snake River. Under 
that consultation, the BLM and grazing permitees have implemented 
actions to reduce the amount of shoreline grazing and grazing-related 
sediment, thereby reducing the risk of take of P. robusta resulting 
from livestock management.
Water Rights and Operations
    In Idaho, there have been improvements in Snake River water 
management since the time of listing the Idaho springsnail in 1992 (57 
FR 59244). Portions of the Snake River are temporarily protected from 
further allocation of consumptive use water rights (Barker et al. 2005) 
by order of the Director of the Idaho Department of Water Resources, 
although this does not preclude future water diversion or consumption 
projects within the range of Pyrgulopsis robusta in the Snake River of 
Idaho. For the other geographic areas where P. robusta occurs, we are 
not aware of any State-sponsored programs restricting allocation of 
consumptive use water rights.
    The U.S. Bureau of Reclamation (BOR) operates numerous water 
projects in the Snake River basin and is involved in a variety of fish 
and wildlife conservation efforts through a number of different 
programs in Oregon, Washington, and Idaho (USBOR 2005). The BOR has 
conducted numerous surveys for sensitive mollusks for several years 
(USBOR 2002, p. 2; 2003, p. 2; 2004, p. 2). Pyrgulopsis robusta has not 
been found in the upper reaches of the Snake River. The BOR has 
developed 10-year Resource Management Plans designed to create a 
balance of resource development, recreation, and protection of natural 
and cultural resources for the lands and waters they manage. These 
plans outline resource management policies and actions that will be 
implemented to protect natural resources (e.g., sensitive mollusk 
species) over each plan's 10-year life (USBOR 2005).
    The U.S. Army Corps of Engineers (USACE) operates several 
hydroelectric projects on the Columbia River within the known range of 
Pyrgulopsis robusta, including John Day, Dalles, and Bonneville Dams. 
Since passage of the National Environmental Policy Act of 1969, 
environmental protection has been an important mission for the 
Northwestern Division of the Corps (USACE 2005). Since legislation 
passed in 1990 establishing environmental protection as one of the 
primary missions of water resource projects, the Corps has taken steps 
to ensure that projects meet Federal, State, and local environmental 
requirements (USACE 2005).
    A Settlement Agreement between the IPC and Service concerning the 
relicensing of IPC's mid-Snake and C.J. Strike hydroelectric projects 
(IPC and USFWS 2004) requires IPC to implement studies to assess 
effects on two listed Snake River aquatic snails, including Pyrgulopsis 
robusta, from operation of hydroelectric dams. The 1992 listing rule 
stated that proposals for numerous small hydroelectric projects to be 
developed on remaining free-flowing portions of the middle Snake River 
within the species' range, threatened the Idaho springsnail. However, 
those proposals have subsequently been withdrawn or were not approved 
by the Federal Energy Regulatory Commission (FERC) (Barker et al. 
2005), reducing the likelihood of new FERC licensed hydroelectric 
projects impacting P. robusta.
Summary of Factor D
    A wide variety of regulatory mechanisms managed by State and 
Federal resource agencies are in place to manage and protect 
Pyrgulopsis robusta and the habitats upon which it depends. Federal 
land management plans address conservation of P. robusta habitats, and 
Federal and State agencies are managing water projects to minimize 
impacts on P. robusta and protect the water quality where the species 
occurs. Water withdrawals for the allocation of consumptive water use 
in the Snake River basin have been halted through a temporary 
moratorium by the State of Idaho. Additionally, IPC hydroelectric 
projects on the Snake River in Idaho have begun to address P. robusta 
management needs via specific commitments in recent Settlement 
Agreements. Given that P. robusta occurs as multiple populations 
distributed over a wide geographic area, and a wide range and variety 
of habitat types, the variety of State and Federal regulatory 
mechanisms that directly and indirectly provide conservation benefits 
for P. robusta are generally considered adequate.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    Numerous non-native and invasive species have become established 
throughout the range of Pyrgulopsis robusta, and others threaten to 
become established; however, their impacts on native species and 
ecosystems have not been well studied or understood. (Frest and 
Johannes 2000, p. 1; Anderson 2004, pp. 15-18; Sytsma et al. 2004, pp. 
33-34).
    In the 1992 listing rule (57 FR 59244) for the Idaho springsnail, 
we stated that the New Zealand mudsnail (Potamopyrgus antipodarum) was 
a potential threat to the Idaho springsnail. The New Zealand mudsnail 
was discovered in North America in 1987 in the Snake River, and has 
spread rapidly (Bowler 1991, p. 175; Richards and Lester 2003, p. 1; 
Richards et al. 2004, p. 114). The New Zealand mudsnail appears to 
flourish in warm waterbodies in Wyoming and Montana on substrates of 
silt to cobbles (Hall et al. 2003, p. 407; Cada 2004, p. 29), but is 
also reported to reach high densities within the much cooler waters of 
the Snake River (Clark et al. 2005, p. 17). The wide physical and 
physiological tolerances of the New Zealand mudsnail allow it to thrive 
in various habitats (Richards et al. 2001, pp. 375, 378; Hall et al. 
2003, p. 408). The ability of the New Zealand mudsnail to occupy 
numerous habitat types, including those typically occupied by native 
snails (Richards et al. 2001, pp. 375, 378; Richards 2004, pp. 137-
139), does not always provide a competitive advantage for the New 
Zealand mudsnail in interactions with native species (Cowie 2004).
    In the Greater Yellowstone Ecosystem, researchers found evidence 
that New Zealand mudsnails limit the colonization of, and may influence 
the large-scale distribution of, other macroinvertebrates (Kerans et 
al. 2005, p. 135). Research in Wyoming has demonstrated that New 
Zealand mudsnails have reduced densities of Pyrgulopsis robusta in 
Polecat Creek in Yellowstone National Park, but P. robusta and New 
Zealand mudsnails continue to co-exist (Riley et al. 2003, pp. 16-18; 
Gustafson 2005, pp. 7-8). The threat the New Zealand mudsnail poses to 
P. robusta remains uncertain. However, the New Zealand mudsnail does 
not appear to currently endanger or threaten P. robusta throughout all 
or a significant portion of its range.
    The Expert Panel and Service's Manager Panel identified the threat 
of non-native species, including the New Zealand mudsnail, to 
Pyrgulopsis robusta's survival as low. Both panels

[[Page 56947]]

identified the lack of information about non-native species 
interactions with P. robusta as an area of uncertainty. However, direct 
cause and effect information that non-native species are endangering or 
threatening P. robusta populations does not exist.
    Thus, based on the best scientific and commercial data available, 
we have concluded that other natural and manmade factors do not 
endanger or threaten Pyrgulopsis robusta throughout all or a 
significant portion of its range.

Summary of Threats Section

    Evidence collected since the Idaho springsnail was listed in 1992 
as endangered (57 FR 59244) indicates Pyrgulopsis idahoensis no longer 
constitutes a distinct species. The revised species, Pyrgulopsis 
robusta, is a combined taxon composed of four previously regarded as 
taxonomically distinct springsnails--the Idaho, Jackson Lake, Harney 
Lake, and Columbia River springsnails.
    Pyrgulopsis robusta populations in the Columbia and Snake Rivers 
have relatively high abundance and occur as multiple populations 
distributed over a wide geographic area. The Columbia River population 
of P. robusta is currently known from 17 locations starting from river 
mile 20 (rkm 32) and continuing for nearly 400 river miles (644 rkm) 
upstream to just below Priest Rapids Dam. In the Snake River, P. 
robusta is more widely distributed than originally cited in the 1992 
listing rule and has been documented at over 174 known locations, over 
214 river miles (344 km). The species occurs in a range of habitat 
types, and is resilient to changes in flow and water quality. Extant 
populations occur in various habitats, including springs, and river 
reaches characterized by a wide range of flow conditions, and both 
occur in lake and reservoir locations. Pyrgulopsis robusta has adapted 
to, and survives in, a relatively wide range of temperatures. 
Fluctuating water temperatures likely do not limit growth, 
reproduction, or survival of P. robusta in any portion of its range. 
Adequate existing regulatory mechanisms contributing to P. robusta 
conservation include water quality regulations and FERC hydropower 
Settlement Agreements. At this time P. robusta exists in multiple 
populations in the States of Oregon, Washington, Idaho, and Wyoming and 
is expected to persist into the future. We evaluated the best available 
scientific and commercial data regarding status of and threats to the 
newly described P. robusta, and determined that the species is not in 
danger of extinction, nor is it likely to become endangered in the 
foreseeable future throughout all or a significant portion of its 
range, and therefore does not meet the definition of threatened or 
endangered.

Finding

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
faced by this species. We reviewed the petitions, available published 
and unpublished scientific and commercial information, and information 
submitted to us during the public comment period following our 90-day 
petition findings. This finding reflects and incorporates information 
we received during the public comment period and responds to 
significant issues (i.e., incorporates appropriate information raised 
in comments regarding P. robusta taxonomy, life history, distribution, 
status, and threats). We also consulted with recognized springsnail 
experts and Federal and St