[Federal Register Volume 63, Number 193 (Tuesday, October 6, 1998)]
[Proposed Rules]
[Pages 53620-53623]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26737]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AC13


Endangered and Threatened Wildlife and Plants; Withdrawal of 
Proposed Rule to List the San Xavier Talussnail (Sonorella eremita) as 
Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule; withdrawal.

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SUMMARY: The Fish and Wildlife Service (Service) withdraws a proposal 
to list the San Xavier talussnail (Sonorella eremita) as an endangered 
species under the Endangered Species Act of 1973, as amended. This 
species occurs on a hillside on private property in Pima County, 
Arizona. Following publication of the proposed rule, the Service 
gathered additional information on land ownership, and a conservation 
agreement was completed which reduces threats to the species to a level 
at which listing as threatened or endangered is not warranted.

ADDRESSES: The complete file for this rule is available for inspection, 
by appointment, during normal business hours at the Arizona Ecological 
Services Field Office, 2321 W. Royal Palm Road, Suite 103, Phoenix, 
Arizona 85021.

FOR FURTHER INFORMATION CONTACT: Debra Bills at the above address or 
telephone 602/640-2720.

SUPPLEMENTARY INFORMATION:

Background

    The San Xavier talussnail (Sonorella eremita) is a land snail and 
was first described in 1910 by H.A. Pilsbry and L.E. Daniels (Pilsbry 
and Ferriss 1915). The species has a globose (globular) shell with as 
many as 4.5 whorls, a white to pinkish tint and a chestnut-brown 
shoulder band. It is approximately 19 millimeters (0.7 inches) in 
diameter. Its shell is very typical of desert Sonorella (Pilsbry and 
Ferriss 1915).
    The San Xavier talussnail lives in a deep, northwestward facing, 
limestone rockslide in Pima County, Arizona. Its habitat is protected 
from drying effects of the sun by outcrops of limestone and decomposed 
granite to the northeast and southwest, and by the hill itself to the 
southeast (Pilsbry and Ferriss 1915, Hoffman 1990). The vegetation, 
slope of the hillside, and depth of the slide provide necessary 
moisture conditions. The talussnail is similar to other Sonorella 
species in that it feeds on fungus or decaying plant material (Hoffman 
1990). The San Xavier talussnail is hermaphroditic (has both male and 
female reproductive organs) (Morton 1968, Hoffman 1990). After a rain, 
the snail will lay eggs, feed, and mate. Fertilization and production 
of eggs takes several days. If the rains are short-lived, the snails 
hold the eggs until the next rain. The species requires 3 or 4 years to 
mature, depending on rainfall frequency, and has a reproductive life of 
4 to 6 years, depending on the number of days it remains active 
(Hoffman 1990).
    Talussnails are sensitive to drying and sedimentation resulting 
from disturbance of the talus slope and associated vegetation. In 
general, desert snails are known to protect themselves from drying by 
crawling into deep, cool rockslides that are not filled with soil. The 
limestone rock or other talus that contains calcium carbonate is 
crucial to the species as it aids in shell deposition and neutralizes 
carbonic acid that is produced during estivation (period of inactivity) 
(Hoffman 1990). The San Xavier talussnail is known to estivate for up 
to three years and in most years is only active for three or four days 
(Hoffman 1990).
    With the assistance of global positioning system units in February, 
1998, the Service and the Arizona Game and Fish Department were able to 
obtain the exact location of the talus slope and identify the correct 
landowner. Discussions with this landowner led to a revised assessment 
of the threats faced by the San Xavier talussnail and the talus slope 
on which it resides.

Previous Federal Action

    We included the San Xavier talussnail as a Category 2 candidate 
species in our May 22, 1984, notice of review of candidate 
invertebrates (49 FR 21664) and in our January 6, 1989, animal 
candidate Notice of Review (54 FR 554). Category 2 species were those 
taxa for which we had information indicating that listing may be 
warranted but for which the information was insufficient to support 
issuance of proposed listing rules. We included the San Xavier 
talussnail as a Category 1 candidate species in our November 21, 1991, 
animal candidate notice of review (56 FR 58804). Category 1 species 
were those taxa for which we had sufficient information to support 
issuance of listing proposals. We published a proposal to list this 
species in the Federal Register on March 23, 1994 (59 FR 21664). 
Publication of the proposal initiated a comment period which expired on 
May 23, 1994.
    Processing of a final determination on the proposed rule to list 
the San Xavier

[[Page 53621]]

talussnail was delayed by the moratorium on final listings imposed on 
April 10, 1995 (Public Law 104-6). Following lifting of the moratorium 
and restoration of significant funding for listing through passage of 
the Omnibus Budget Reconciliation Law on April 26, 1996, we developed 
listing priority guidance (May 16, 1996, 61 FR 24722) to clarify the 
order in which we would process rulemakings. We commenced work on 
resolving outstanding proposed listings in accordance with this listing 
priority guidance and following revised guidances (December 5, 1996, 61 
FR 64475; October 23, 1997, 62 FR 55268; May 8, 1998, 63 FR 25502).
    Processing of this withdrawal conforms with our current listing 
priority guidance for Fiscal Years 1998 and 1999, published on May 8, 
1998 (63 FR 25502). The guidance gives highest priority (Tier 1) to 
processing emergency rules to add species to the Lists of Endangered 
and Threatened Wildlife and Plants (Lists); second priority (Tier 2) to 
processing final determinations on proposals to add species to the 
Lists, processing new proposals to add species to the Lists, processing 
administrative findings on petitions (to add species to the Lists, 
delist species, or reclassify listed species), and processing a limited 
number of proposed or final rules to delist or reclassify species; and 
third priority (Tier 3) to processing proposed or final rules 
designating critical habitat. Processing of this withdrawal is a Tier 2 
action.
    Because of the new information on landowner status, and in 
consideration of the length of time that had elapsed since issuance of 
the proposal on March 23, 1994, and expiration of the initial comment 
period on May 23, 1994, we opened a second public comment period from 
May 22, 1998, to July 21, 1998 (63 FR 28343). We sought comments or 
suggestions from the public, other concerned governmental agencies, the 
scientific community, industry, and other interested parties. We 
requested new information that may have developed in the intervening 
period since the proposal was first published and that would expand the 
current knowledge concerning the status, distribution, or security of 
the San Xavier talussnail or any factor affecting the species or its 
habitat. During this public comment period, discussions with the 
landowner led to the development of a draft conservation agreement for 
the species and its habitat. We then published another notice in the 
Federal Register on June 23, 1998 (63 FR 34142), announcing the 
availability of this draft conservation agreement for review and 
comment. We accepted comments on the draft conservation agreement until 
the July 21, 1998, closing of the second public comment period.
    The parties to the conservation agreement, the Service, the Arizona 
Game and Fish Department, El Paso Natural Gas Company (EPNG), and the 
Arizona Electric Power Cooperative, Inc. (AEPCO), finalized and signed 
the conservation agreement on September 23 and 24, 1998. The 
conservation agreement provides the following protective measures:
    1. An Advisory Committee will be established, consisting of a 
representative of each party to the conservation agreement, to evaluate 
the results of implementation of the conservation agreement and make 
recommendations for revisions.
    2. The area encompassing and adjacent to the habitat of the snail 
(the ``Area of Concern'') will not be modified.
    3. The Advisory Committee will agree upon and mark the corners of 
the Area of Concern and will include the area that drains into the 
talus slope.
    4. Rock, soil, or construction material will not be placed in the 
Area of Concern.
    5. The dirt road above the Area of Concern will not be widened.
    6. Routine road maintenance will be conducted so as not to change 
the hydrology of the Area of Conern.
    7. Herbicides will not be applied near the Area of Concern.
    8. EPNG or AEPCO will notify the other parties to the agreement and 
take precautions when working on microwave facilities on the hilltop.
    9. The Advisory Committee will review all plans for change in 
management and ensure sufficient mitigation measures are provided to 
maintain protection for the species.

Public Comments

    In the March 23, 1994, proposed rule (59 FR 21664) and the 
associated notifications, we asked all interested parties to submit 
factual reports or information that might contribute to development of 
a final rule. We contacted appropriate State agencies and 
representatives, scientific organizations, and other interested parties 
and requested comments. We published newspaper notices for the proposed 
listing and comment period, and the reopening of the public comment 
period in the Tucson Citizen and the Arizona Daily Star.
    The proposed rule to list this species pre-dated our policy to seek 
independent peer review of listing actions (59 FR 34270, published July 
1, 1994). However, during the open comment periods, we solicited the 
expert opinions of appropriate independent specialists regarding 
pertinent scientific or commercial data relating to the taxonomy and 
ecology of the San Xavier talussnail. However, we did not receive any 
responses from the reviewers.
    In the following summary, we address the comments received during 
the two comment periods that indicate opposition to withdrawing the 
proposed rule. We grouped comments of a similar nature into one of nine 
general issues.
    Issue 1: One commenter questioned what type of land use 
restrictions and enforcement actions might result from enactment of the 
conservation agreement.
    Service Response: Because the current landowners have no plans to 
develop the habitat of the San Xavier talussnail, agreeing to protect 
the site by entering into the conservation agreement did not restrict 
any current or planned land use of the site. If the conservation 
agreement is not implemented, and if threats to the species are not 
addressed through other means, we will consider reinitiating the 
listing process for the species.
    Issue 2: Certain threats to the San Xavier talussnail identified in 
the proposed rule, including new mining, expansion of a nearby large 
copper mine, use of herbicides, vandalism, excessive collection, and 
predation, continue to threaten the species.
    Service Response: As described in detail in the ``Summary of 
Factors Affecting the Species'' section of this notice, we believe that 
new information, including protection offered by the conservation 
agreement, indicates that the threats to the San Xavier talussnail 
described in the proposed rule are substantially reduced.
    During the past public comment period, we discovered that EPNG, 
which owns the talus slope and is a signatory to the conservation 
agreement, also owns all mining claims on the talus slope. The large 
mine nearby currently has no plan to expand in the area of the talus 
slope.
    AEPCO, which owns a microwave facility at the top of the hill and 
maintains the road, has never applied herbicides to the road or 
anywhere near the talus slope. Although herbicides may be used upslope 
at the microwave facility, the application is confined to the microwave 
facility fenced area and consists of annual pre-emergent application 
between November and March. We have not documented any instances of 
adverse effects to the San Xavier talussnail from herbicide

[[Page 53622]]

application, and we do not anticipate any effects in the future.
    The parties to the conservation agreement recognize the potential 
threat to the San Xavier talussnail from vandalism and excessive 
collection. Because both AEPCO and EPNG are also concerned about 
vandalism of the microwave facility, access to the site is restricted. 
The parties to the conservation agreement are evaluating the need for 
fencing, and replacing or adding ``No Trespassing'' signs at the site, 
particularly in areas used by dirt bikes.
    Rodent predation is random and sporadic on the San Xavier 
talussnail (Hoffman 1990). We have no information indicating that 
rodent predation is above natural levels or that it poses a significant 
threat to the species.
    Issue 3: Infiltration of sediment from the dirt road passing near 
the talus slope may continue to threaten the San Xavier talussnail.
    Service Response: Access to the road is restricted by a locked 
gate. AEPCO's use of the road is primarily by microwave technicians who 
visit the microwave facility once every other month. An equipment 
problem may require daily visits until remedied, but this is rare. 
Information provided by AEPCO shows that since the construction of the 
road in 1978, maintenance has been conducted on the road on six 
occasions. The last time a grader worked the entire road was December 
1990. We have not documented any adverse effects to the San Xavier 
talussnail resulting from past road maintenance.
    As specified in the conservation agreement, AEPCO will coordinate 
future road maintenance with the Advisory Committee and will not 
conduct maintenance during the talussnail's active period except in 
emergencies. We believe these precautions adequately protect the 
species from road maintenance.
    Issue 4: The 5-year time frame mentioned in the draft conservation 
agreement is insufficient to protect the talussnail.
    Service Response: Although the draft conservation agreement 
specified a duration of five years with the possibility to be extended 
another five years, the final conservation agreement specifies a 
duration of ten years. In addition, the parties to the conservation 
agreement have committed to an annual review to ensure protection is 
sufficient. If, after the conservation agreement expires, threats to 
the species are not addressed by renewal of the conservation agreement 
or other means, we will evaluate the status of the species and consider 
reinitiating the listing process.
    Issue 5: Because the San Xavier talussnail occurs only at a single, 
small site, a single catastrophic event could be devastating for the 
species.
    Service Response: As far as we know, the talussnail has always been 
limited to this single, small site. Because the species has persisted 
under these natural conditions, we do not believe that natural 
catastrophic events pose a significant threat to the species. The 
potential human-caused catastrophic events include significant 
disturbance to the talus slope or upslope areas. We believe that the 
measures specified in the conservation agreement sufficiently reduce 
the likelihood that such human-caused catastrophic events will occur.
    Issue 6: Vandalism and excessive collection remain a threat because 
the talus slope can be accessed easily from the bottom.
    Service Response: Although no physical barriers exist to absolutely 
prevent access to the site, we believe that the conservation agreement 
adequately addresses the threats of vandalism and overcollection. The 
species is located on private land, and trespassing is prohibited. The 
parties to the agreement are evaluating the need for fencing or 
additional ``No Trespassing'' signs to further discourage trespassing. 
In addition, anyone collecting San Xavier talussnails or otherwise 
taking them would be guilty of violating State of Arizona wildlife 
regulations (see factor D of the ``Summary of Factors Affecting the 
Species'' section).
    Issue 7: Emergency road work or other emergencies, which the 
conservation agreement exempts from review and approval by the Advisory 
Committee, poses a threat to the San Xavier talussnail.
    Service Response: Major damage to the microwave tower, tower 
equipment, or control building resulting from fire, vandalism, or 
extreme weather conditions are considered emergencies requiring 
immediate repairs. Also, damage to the road causing it to be impassable 
would also be considered an emergency requiring immediate repairs. 
Routine maintenance to these facilities is not considered an emergency. 
AEPCO and EPNG have agreed to notify the other parties to the 
conservation agreement as soon as practicable after discovery of an 
emergency situation.
    Issue 8: One commenter questioned the reference to ``reasonable 
precautions'' in the conservation agreement to prevent rock, soil, or 
construction material from being transported to the talus slope.
    Service Response: Possible changes at the microwave site include 
construction of an additional tower, a larger control building, and 
additional fences. All of these activities have the potential to result 
in material being transported to the talus slope. In accordance with 
the conservation agreement, the Advisory Committee will review all 
plans for change and recommend mitigation measures. Mitigation measures 
could include removing excess materials and establishing temporary 
barriers, silt fences, or hay bales downhill from the construction 
area.
    Issue 9: The ``No Surprises'' clause in the draft conservation 
agreement shows the inadequacy of existing regulatory mechanisms to 
protect the San Xavier talussnail.
    Service Response: All references to ``No Surprises'' assurances 
have been omitted in the final conservation agreement.

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 adding species to the Federal lists. We may determine a species to 
be an endangered or threatened species due to one or more of the five 
factors described in Section 4(a)(1). These factors and their 
application to our decision to withdraw the proposal to list the San 
Xavier talussnail are as follows:

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

    The San Xavier talussnail is a very restricted endemic species and 
is vulnerable to any disturbance that would remove talus, increase 
interstitial (the spaces between the talus) sedimentation, or otherwise 
alter moisture conditions (e.g., road or trail expansion or alteration, 
mining exploration) (Hoffman 1990). We believe that new information 
received since the publication of the proposed rule, and the 
protections provided by the recently finalized conservation agreement, 
indicate that threats to the species' habitat are not as great as 
supposed or have been substantially reduced through adoption of the 
conservation agreement.
    A large, active copper mine, as well as inactive mining prospects 
and mines, are located in the vicinity of the talus slope. During the 
past public comment period, we discovered that EPNG, which owns the 
talus slope and is a signatory to the conservation agreement, also

[[Page 53623]]

owns all mining claims on the talus slope. The large copper mine 
currently has no plan to expand in the area of the talus slope.
    There are housing developments of small acreages to the north and 
to the southwest of the hill. However, the talus slope is too steep (30 
to 40 percent slope) to permit housing construction.
    A road leading to a microwave site on the hilltop passes near the 
talus slope. This road receives very little traffic; microwave 
technicians may visit the site once every other month, unless there is 
a problem on the ground which may require more frequent visits. Access 
to the road by the public is restricted by a locked gate. Information 
provided by AEPCO shows that since the construction of the road in 
1978, maintenance has been conducted on the road on six occasions. The 
last time a grader worked the entire road was December 1990. We have 
not documented any adverse effects to the San Xavier talussnail 
resulting from past road maintenance. The conservation agreement 
specifies that future road maintenance will be coordinated with the 
Advisory Committee and will not occur during the talussnail's active 
period except in emergencies. We believe these precautions adequately 
protect the species from road maintenance.

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

    Although we do not have any information indicating that any 
significant collection of the San Xavier talussnail is occurring, the 
extremely restricted distribution of the species makes it vulnerable to 
overcollection during periods when the snails are active. Trespassing 
on the talus slope is prohibited, vehicle access to the site is 
restricted by a locked gate, and collection of the species is 
prohibited by Arizona State law (see factor D). Also, additional 
measures are being evaluated to further discourage trespassing and 
collection. For these reasons, we believe that the potential threat of 
overcollection of the species is small and not significant enough to 
warrant listing the species at this time.

C. Disease or Predation

    We do not know of any diseases affecting the San Xavier talussnail. 
Rodent predation is random and sporadic on the species (Hoffman 1990). 
However, we do not have any evidence indicating that rodent predation 
is or may be a limiting factor for this species.

D. The Inadequacy of Existing Regulatory Mechanisms

    The State of Arizona has placed the San Xavier talussnail on the 
1998 Crustaceans and Mollusks Commission Order 42 and the list of 
sensitive elements that qualify for Heritage funding. This designation 
makes it illegal to collect or possess the species. The species occurs 
on private land, and trespassing is prohibited. In addition, the 
conservation agreement provides a framework for continued protection 
and management of the San Xavier talussnail and its habitat. We believe 
these provisions are adequate for the conservation of the species.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    The very restricted range of the San Xavier talussnail makes it 
vulnerable to catastrophic events. As far as we know, the talussnail 
has always been limited to the single, small site where it currently 
exists. Because the species has persisted under these natural 
conditions, we do not believe that natural catastrophic events pose a 
significant threat to the species. Potential human-caused catastrophic 
events include significant disturbance, including vandalism, to the 
talus slope or upslope areas. We believe that the measures specified in 
the conservation agreement addressing construction activities, road 
maintenance, and trespassing sufficiently reduce the likelihood that 
such human-caused catastrophic events will occur.

Finding and Withdrawal

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the San Xavier talussnail. Population trend information is 
unavailable, but the species' habitat is secure. We no longer believe 
that the San Xavier talussnail is in danger of extinction throughout 
all or a significant portion of its range or is likely to become so in 
the foreseeable future. We therefore withdraw the proposed rule to list 
the San Xavier talussnail under the Endangered Species Act.
    We will work to gather additional information on the status and 
ecology of the San Xavier talussnail. Also, we will participate with 
parties to the conservation agreement to ensure the long-term survival 
of this species. If new information becomes available indicating the 
presence of a new threat to the San Xavier talussnail or an increase in 
the severity of a threat, and if the threats are not adequately 
addressed through revision of the conservation agreement or other 
means, we will consider reinitiating the listing process for the 
species.

References Cited

Hoffman, J.E. 1990. Status survey of seven land snails in the 
Mineral Hills and the Pinaleno Mountains, Arizona. Prepared for U.S. 
Fish and Wildlife Service, Phoenix, Arizona. Contract Number: 20181-
88-00973.
Morton, J.E. 1968. Molluscs. Hutchinson University Library. London. 
244 pp.
Pilsbry, H.A. and J.A. Ferriss. 1915. Mollusca of the southwestern 
states. VII. The Dragoon, Mule, Santa Rita, Baboquivari and Tucson 
Ranges, Arizona. Proc. Acad. Nat. Sci. Phila. 67:363-418; Pls. 8-15.

    Author: The primary author of this document is Debra Bills, Arizona 
Ecological Services Field Office (see ADDRESSES section).

    Authority: The authority for this action is section 
4(b)(6)(B)(ii) of the Endangered Species Act of 1973, as amended (16 
U.S.C. 1531 et seq.).

    Dated: September 29, 1998.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 98-26737 Filed 10-5-98; 8:45 am]
BILLING CODE 4310-55-P