65FR35033 Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for the Buena Vista Lake Shrew
robop...@us.govnews.org
Posting-number: Volume 65, Issue 106, Page 35033
[Federal Register: June 1, 2000 (Volume 65, Number 106)]
[Proposed Rules]
[Page 35033-35040]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01jn00-40]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
RIN 1018-AGO4
Endangered and Threatened Wildlife and Plants; Proposed
Endangered Status for the Buena Vista Lake Shrew
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to
list the Buena Vista Lake shrew, Sorex ornatus relictus, as endangered
pursuant to the Endangered Species Act of 1973, as amended (Act). Prior
to 1986, this subspecies had not been observed since it was first
described in 1932. In 1986, three Buena Vista Lake shrews were observed
at a permanent pond located within a former preserve, approximately 26
kilometers (km) (16 miles (mi)) south of Bakersfield, CA. No more than
38 individuals have been observed since they were rediscovered in 1986.
The only known extant Buena Vista Lake shrew population is threatened
primarily by agricultural activities, modifications and potential
impacts to local hydrology, uncertainty of water delivery, possible
toxic effects from selenium poisoning, and random naturally occurring
events. This proposal, if made final, would implement the Federal
protection and recovery provisions afforded by the Act for the Buena
Vista Lake shrew.
DATES: We must receive comments from all interested parties by July 31,
2000. Public hearing requests must be received by July 17, 2000.
ADDRESSES: Send your comments and materials concerning this proposal to
the Field Supervisor, Sacramento Fish and Wildlife Office, U.S. Fish
and Wildlife Service, 2800 Cottage Way, Rm W-2605, Sacramento,
California 95825. Comments and materials received, as well as the
supporting documentation used in preparing the rule, will be available
for public inspection, by appointment, during normal business hours at
the above address.
FOR FURTHER INFORMATION CONTACT: Dwight Harvey, Sacramento Fish and
Wildlife Office (see ADDRESSES section) (telephone 916/414-6600;
facsimile 916/414-6710).
SUPPLEMENTARY INFORMATION:
Background
The Buena Vista Lake shrew, Sorex ornatus relictus, is one of nine
subspecies within the ornate shrew Sorex ornatus species complex known
to occur in California (Hall 1981; Owen and Hoffmann 1983; Maldonado
1992). Sorex ornatus belongs to the order Insectivora and family
Soricidae, subfamily Soricinae, and the tribe Soricini, with three
subgenera (Owen and Hoffmann 1983; Junge and Hoffmann 1981).
Sorex ornatus relictus are primarily insectivorous mammals that are
the approximate size of a mouse. They have a long snout, tiny bead-like
eyes, ears that are concealed, or nearly concealed, by soft fur, and
five toes on each foot (Ingles 1965; Burt and Grossenheider 1964).
Sorex ornatus relictus are active day or night. When they are not
sleeping, they are searching for food. These shrews eat more than their
own weight each day (Burt and Grossenheider 1964) to withstand
starvation and maintain their body weight at high rates of metabolism
(McNab 1991). Sorex ornatus relictus can have an impact on surrounding
plant communities by consuming large quantities of insects, slugs, and
other invertebrates that can influence such things as plant succession
and control the irruptions of pest insects (Maldonado 1992; Williams
1991). Sorex ornatus relictus also may be an important prey species for
raptors, snakes, and carnivores (Maldonado 1992).
Grinnell (1932) was the first to describe Sorex ornatus relictus.
According to Grinnell's description, the Buena Vista Lake shrew's back
is predominantly black with a buffy-brown speckling pattern, its sides
are more buffy-brown than the upper surface, and its underside is
smoke-gray. The tail is faintly bicolor and blackens toward the end
both above and below. The Buena Vista Lake shrew weighs approximately 4
grams (g) (0.14 ounces (oz)) (Kathy Freas, Stanford University, pers.
comm. 1994) and has a total length ranging from 98 to 105 millimeters
(mm) (3.85 to 4.13 inches (in.)) with a tail length of 35 to 39 mm
(1.38 to 1.54 in.) (Grinnell 1932). The Buena Vista Lake shrew differs
from its geographically closest subspecies, the ornate shrew Sorex
ornatus spp. ornatus, by having darker, grayish-black coloration,
rather than brown. In addition, S. o. ssp. relictus has a slightly
larger body size; shorter tail; skull with a shorter, heavier rostrum;
and a higher and more angular brain-case in dorsal view than S. o. ssp.
ornatus (Grinnell 1932).
Ornate shrews, on the average, rarely live longer than 12 months,
and evidence indicates that the normal
[[Page 35034]]
lifespan does not exceed 16 months (Rudd 1955). In montane woodlands,
shrews have a well-defined reproductive season that lasts from mid-May
through August (Williams 1991). They give birth to up to two litters
per year containing four to six young. The number of litters depends on
how early or late in the year the young are born and can become
sexually active (Owen and Hoffmann 1983). The Buena Vista Lake shrew
has a breeding season that begins in February or March, and may either
extend later in the year, based on habitat quality and availability of
water, or end with the onset of the dry season in May or June (Jesus
Maldonado, University of California-Los Angeles, pers. comm. 1998).
The Buena Vista Lake shrew was originally described by Grinnell
(1932) as a new subspecies, Sorex ornatus relictus, based on the type
specimen and two other specimens collected around the old Buena Vista
Lake bed. On October 21, 1909, a single specimen of S. o. ssp. relictus
was collected at Buttonwillow, a town approximately 40 km (25 mi)
northwest of Buena Vista Lake (Williams 1986; Doug Long, California
Academy of Sciences, pers. comm. 1998). Grinnell (1932) noted evidence
that integration between the subspecies Sorex ornatus ornatus and S. o.
ssp. relictus occurred in areas of geographic overlap. This integration
prompted Freas (1990) to question the legitimacy of the Buena Vista
Lake shrew's status as a distinct subspecies. Currently, the entire
Sorex ornatus complex (consisting of eight subspecies in California and
one in Baja California) is undergoing additional genetic and
morphological evaluation (J. Maldonado, pers. comm. 1998). Preliminary
results from strictly morphological measurements for this group were
equivocal throughout California. However, mitochondrial DNA and micro-
satellite nuclear sequences and allozyme data have aided in determining
subspecies ranges. From these data, researchers determined that the
Buena Vista Lake shrew is a distinct subspecies from other S. ornatus
subspecies; it is unlike any other sampled throughout the southern San
Joaquin Valley (J. Maldonado, pers. comm. 1998).
Based on Grinnell's (1933) records in the Museum of Vertebrate
Zoology at Berkeley (three museum specimens and related field notes),
the distribution of the Buena Vista Lake shrew was historically limited
to the marshlands of the southern San Joaquin Valley south from
approximately where the waters of the Kings River divide toward the San
Joaquin River and bed of Tulare Lake, with the animals living in the
swampy margins of Kern, Buena Vista, Goose, and Tulare Lakes. However,
by the time the shrew was discovered, Grinnell stated that the beds of
these lakes were already dry and mostly cultivated with only sparse
remnants of the original fauna (Grinnell 1932). Williams (1986) stated
that nearly all of the valley floor in the Tulare Basin is cultivated
and that most of the lakes and marshes had been drained and cultivated.
The Buena Vista Lake shrew was likely historically distributed in
the marshlands of the San Joaquin Valley throughout most of the Tulare
Basin (Grinnell 1933; U.S. Fish and Wildlife Service 1997). The Buena
Vista Lake shrew occurs on property owned by the J.R. Boswell Company
(Company), formerly known as the Kern Lake Preserve (Preserve), on the
old Kern Lake bed, in Kern County, California (California Natural
Diversity Data Base (CNDDB)1986). This property totals about 33.5
hectares (ha) (83 acres (ac)), and the only known viable population of
Buena Vista Lake shrews inhabits a small 1.2-ha (3-ac) wetland area
that exists there. Although the Preserve has remained relatively
unchanged since the Buena Vista Lake shrew was detected at this site in
1986, the future management of the Preserve and the future existence of
this subspecies is uncertain.
Water is a necessary component of the Buena Vista Lake shrew's
environment. Moisture is required to support a diverse insect fauna,
which is the primary food source needed to maintain the shrew's high
metabolism. During surveys conducted on the Preserve in 1988 and 1990,
Freas (1990) found a clear trend in preference of moderately moist
(mesic) habitats over drier (xeric) habitats by the shrew, with 25
animals being captured in the mesic environments and none in xeric
habitat. Maldonado (1992) also acknowledged this type of habitat
preference, stating that the shrew is closely associated with dense,
riparian understories that provide food, cover, and moisture.
The permanent pond where the subspecies occurs is located within
the Preserve, called Gator Pond, which is not an artesian system. It is
dry for many years, filling only when there is adequate flood runoff,
or as in 1986, when the Company used the area for storage of excess
water (The Nature Conservancy (TNC) in litt. 1986; Rick Hewett, TNC, in
litt. 1987). The Rim Ditch forms the southern border of the Preserve,
and another ditch was installed by the Company to convey irrigation
flows to agricultural land north of the Rim Ditch. The land in and
around the pond has a high (perched) water table because it is
underlined with a natural hardpan soil layer that is somewhat
impervious to water. In the past, this hardpan soil layer kept the area
very wet and prevented it from being productively farmed. In 1982, the
company installed a system of perforated tile line (drain pipes), which
drains water from west to east under the Preserve, then northeast to
the South Sump. Within 1 year, the perched water table began to
subside, and the pond remained dry for the next 3 years (CNDDB 1986).
As a result of the installation of the tile line, the areas northeast
of the pond and southwest of the South Sump became arable allowing
wheat and sorghum to be grown in these areas (TNC, in litt. 1986). The
land west of the pond has never been farmed, but weeds are cleared off
once a year. The land around the pond was disked annually until 1985,
when TNC signed a lease and took over the management of the 33.5-ha
(83-ac) Preserve. Only about 12 ha (30 ac) around the pond is now
suitable habitat for the shrew (J. Maldonado, pers. comm. 1994).
All water that runs north from the Rim Ditch into the tile lines
ends up in the South Sump. The water, referred to as tail water, is
pumped back to the Rim Ditch. The Company agreed they could supply the
excess tail water to the Preserve in the early fall for the TNC leased
area. June through August are the critical irrigation months for the
Company's cotton and alfalfa production. During that period, all
available water is presumably used for these purposes. In 1986, the
Company allowed TNC to install a separate pipe from the Rim Ditch
directly to the pond as a way of providing water to this area. Three
Buena Vista Lake shrew were discovered during the digging of a ditch
for this pipe. (CNDDB 1986).
The Company originally supplied sufficient water to maintain the
marshes on the Preserve. This water was sold to TNC through a lease
agreement (Company, in litt. 1995). The Company committed to supplying
water only during the years when quantities would be available in
excess of that required for other corporate uses, primarily
agriculture. Without this supplemental water supply, the remaining
marshlands will dry up (J. Maldonado, pers. comm. 1994). In 1994, the
Fish and Wildlife Service asked the Company to commit to a conservation
agreement that would support the long-term maintenance of the Preserve
and the survival of the Buena Vista Lake shrew, but the Company
declined. (Edward Gierman, J.G. Boswell Company, in litt. 1995). TNC
was concerned about the long-term health of the Preserve, but
considered it
[[Page 35035]]
a ``non-defensible parcel'' because the land surrounding the Preserve
has been converted to cotton (Reed Tollefson, TNC, pers. comm. 1994).
Water diverted away from the Preserve for agricultural purposes has
caused a drop in the already shallow water table, thereby eliminating
most of the habitat that historically supported the shrew (R. Hewett,
in litt. 1987). TNC staff estimated that proper management of the
Preserve would require 1.9-2.5 hectare-meters (15-20 acre-feet) of
water per year (R. Tollefson, pers. comm. 1995). Without a reliable
water source, TNC declined to renew the lease and terminated their
arrangement with the Company to maintain the Preserve (Sabin Phelps,
TNC, pers. comm. 1995).
Since the rediscovery of the Buena Vista Lake shrew at the
Preserve, the subspecies has been found only three other times. In
1992, one shrew was found alive under a sprinkler cover, and another
was found dead in a manager's residence at the Kern National Wildlife
Refuge (Refuge), Kern County, California (Morgan Cook, Service, pers.
comm. 1995). One additional shrew was found dead in 1994 within the
same residence on the Refuge. This residence is currently the Refuge
headquarters and is one of two buildings located on a 4-ha (10-ac)
compound surrounded by lawns and trees (Jack Allen, Service, pers.
comm. 1998). The Refuge is located approximately 80 km (50 mi)
northwest of the Preserve (Joseph Engler, Service, in litt. 1994).
Water management practices at the Refuge have focused on waterfowl,
and riparian habitat has not received adequate water over the years to
maintain riparian diversity (J. Engler, in litt. 1994). If Sorex
ornatus relictus still exists, it would probably be found around a 323-
ha (800-ac) marsh unit located on the south side of the Refuge where
emergent vegetation, such as willows and cottonwoods exist. The marsh
unit also remains moist longer than most other marshes on the Refuge
(J. Allen, pers. comm. 1998). The constant lawn, shrub, and tree
watering and the ponds at the Refuge headquarters may be sufficient to
maintain any potential shrew populations (J. Engler, in litt. 1994).
Recent genetic data have confirmed that the shrews found at the
Refuge were Buena Vista Lake shrews (J. Maldonado, pers. comm. 1998).
No additional Buena Vista Lake shrews, nor any other shrew species,
have been found at the Refuge.
The elimination of most of the riparian vegetation with associated
marsh habitat that once occurred in the southern San Joaquin Valley has
drastically reduced the amount of suitable habitat available to the
shrew, and may have restricted the animal to the Preserve. Rapid
agricultural, urban, and energy developments since the early 1900s have
severely reduced and fragmented native habitats. Historically, the
Tulare Basin, including the former Tulare, Buena Vista, Goose, and Kern
Lakes with their respective overflow marshes, provided 19 percent of
the Tulare Basin valley floor habitat (Werschkull et al. 1992). Around
the turn of the 20th century, the Tulare Basin had 104,890 ha (259,189
ac) of valley fresh water marsh, 177,005 ha (437,388 ac) of valley
mixed riparian forests, and 105,333 ha (260,283 ac) of valley sink
scrub, making a total of 387,229 ha (956,860 ac) of potentially
suitable Buena Vista Lake shrew habitat. By the early 1980s, the
combined total had been reduced to 19,019 ha (46,996 ac), less than 5
percent of the original habitat (Werschkull et al. 1992). As of 1995,
intensive irrigated agriculture comprised 1,239,961 ha (3,064,000 ac)
or about 96 percent of the total lands within the Tulare Basin. Cotton,
grapes, and alfalfa represented the top three crops (California
Department of Water Resources (DWR) 1998).
All of the natural plant communities in the Tulare Basin have been
affected by the transformation of this area to production of food,
fiber, and fuel at the expense of the natural biological diversity
(Spiegel and Anderson 1992; Griggs et al. 1992). As more canals were
built, and more water was diverted for irrigation of the floodplains of
the major rivers of the southern San Joaquin Valley, less water was
available to keep the riparian forests alive, and less water reached
the lakes. By the early 1930s, the former Tulare, Buena Vista, Goose,
and Kern Lakes were virtually dry and open for cultivation (Griggs
1992).
Irrigation, combined with subsurface drainage, have caused
naturally occurring selenium to be leached from agricultural soils in
the San Joaquin Valley. Elevated concentrations of selenium are
believed to have caused major wildlife mortalities in places like the
Kesterson National Wildlife Refuge (Kesterson) (Moore et al. 1989). The
leaching of selenium has increased in recent times due to the increased
supply of irrigation water for the cultivation of crops in the Tulare
Basin. In 1984, elevated selenium levels in the blood and liver were
measured in several small and large mammals from Kesterson (Clark 1987;
Clark et al. 1989). Ornate shrews captured around Kesterson showed
selenium concentrations (parts per million (ppm) dry weight) 3 to 25
times greater than those found for any other small mammal at the same
site (Clark 1987). As with other forms of wildlife, selenium toxicity
represents a serious threat to the continued existence of the Buena
Vista Lake shrew.
Previous Federal Action
The September 18, 1985, Notice of Review (50 FR 37958), included
the Buena Vista Lake shrew as a category 2 candidate species for
possible future listing as threatened or endangered. Category 2
candidates were those taxa for which listing as threatened or
endangered might be warranted, but for which adequate data on
biological vulnerability and threats were not available to support
issuance of listing proposals.
We received a petition dated April 18, 1988, from Ms. Doris Dixon
of The Interfaith Council for the Protection of Animals and Nature to
list the Buena Vista Lake shrew and three additional shrew species as
endangered species. We determined that the petition presented
substantial information indicating that the requested action may be
warranted. We announced this finding in the Federal Register on
December 30, 1988 (53 FR 53030). The Buena Vista Lake shrew remained a
category 2 candidate in the January 6, 1989, Notice of Review (54 FR
554). In the November 21, 1991, Notice of Review (56 FR 58804), the
Buena Vista Lake shrew was elevated to category 1 status based on new
information received by us. Category 1 taxa were those taxa for which
we had on file sufficient information on biological vulnerability and
threats to support preparation of a listing proposal.
The processing of this proposed rule conforms with our listing
priority guidance published in the Federal Register on October 22, 1999
(64 FR 57114). This guidance clarifies the order in which we will
process future rulemakings. The highest priority is processing
emergency listing rules for any species determined to face a
significant and imminent risk to its well-being (Priority 1). The
second priority (Priority 2) is processing final determinations on
proposed additions to the lists of endangered and threatened wildlife
and plants. The third priority is processing new proposals to add
species to the lists. The processing of administrative petition
findings (petitions filed under section 4 of the Act) is the fourth
priority. This proposed rule ranks as a Priority 3 action.
[[Page 35036]]
Summary of Factors Affecting the Species
Section 4 of the Endangered Species Act (Act) of 1973, as amended
(16 U.S.C. 1533 et seq.), 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 List of Endangered and Threatened
Wildlife. A species may be determined to be endangered or threatened
based on one or more of the five factors described in section 4(a)(1)
of the Act. These factors and their application to the Buena Vista Lake
shrew, Sorex ornatus relictus, are as follows:
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
The amount of suitable habitat for the Buena Vista Lake shrew has
been significantly reduced over time due to the systematic drainage of
land and shallow lakes for the purpose of agricultural crop production.
As a result, over 95 percent of the riparian vegetation and associated
marsh habitat of the southern San Joaquin Valley has been eliminated.
The Buena Vista Lake shrew appears to be restricted to the Preserve
location.
Clark et al. (1982) were unsuccessful in capturing any Buena Vista
Lake shrews in suitable habitat found on TNC's Paine Wildflower
Preserve or at the Voice of America site west of Delano. The Paine
Wildflower Preserve is about 13 km (8 mi) south of the Kern National
Wildlife Refuge and 72 km (45 mi) northwest of the Preserve. The Voice
of America site is located 40 km (25 mi) due east of the Kern Refuge
and 80 km (50 mi) north of the Preserve. No Buena Vista Lake shrews
were found after conducting surveys for small mammals along the Kern
River Parkway in 1987 (Beedy et al. 1992). This area supports 68 ha
(168 ac) of riparian woodlands, as well as 9 ha (22 ac) of freshwater
marshes, and it is located 30 km (19 mi) due north of the Preserve. In
1991, surveys were conducted in suitable habitat on the Tule Elk State
Reserve, 32 km (20 mi) northwest of the Preserve. No shrews were
captured in these surveys (Maldonado 1992). In a 1995 survey at the
Preserve, a total of 10 individuals were trapped (Maldonado 1998).
The only known remaining population of Buena Vista Lake shrews
exists on the Preserve. Water delivery to maintain the Preserve and
support the Buena Vista Lake shrew habitat cannot be assured because
the natural water table has been lowered by past and present
agricultural practices on and around the Preserve. Despite available
water supplies, the Company supplies water to the Preserve only during
years of high runoff, at times when excess water is available at the
end of the growing season, and after commercial crop needs are met.
This process occurs through an informal agreement between the Company
and the lease holder of the property. Without a dependable water supply
of approximately 1.9-2.5 hectare-meters (15-20 acre-feet) required to
maintain the Preserve's marshes, the continued existence of the Buena
Vista Lake shrew is unlikely.
Other remnant patches of suitable habitat that might support the
Buena Vista Lake shrew include areas within the Buena Vista Lake
Aquatic Recreation Area, the Buena Vista Golf Course, and along the
Buena Vista Slough, Goose Lake Slough, and the Kern River west of
Bakersfield, CA (Maldonado 1994; J. Maldonado, pers. comm. 1998; U.S.
Fish and Wildlife Service 1997). Additional areas of suitable moist
locations that might provide remnant shrew habitat occur within the
Pixley National Wildlife Refuge west of the former Tulare Lake bed, as
well as around the former Goose Lake bed. However, small habitat
patches within these areas are marginal at best and would not likely
support a significant number of animals (J. Maldonado, pers. comm.
1998). In addition, these areas represent highly disjunct and
fragmented habitat that may not be reconnected in the foreseeable
future.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The subspecies has no known commercial or recreational value. The
only known extant population of the Buena Vista Lake shrew is on
private property.
C. Disease or Predation
Although there are no documented cases of disease related to Buena
Vista Lake shrews, the possibility of disease and associated threats
exists. The small population size and restricted distribution increases
their vulnerability to epidemic diseases. Buena Vista Lake shrews, like
most small mammals, are host to numerous internal and external
parasites, such as round worms, mites, ticks, and fleas, that may
infest individuals and local populations in varying degrees with
varying adverse effects (J. Maldonado, pers. comm. 1998). However, the
significance of the threat of disease and parasites to the Buena Vista
Lake shrew is not known.
Most carnivores of the Tulare Basin, such as coyotes, foxes,
weasels, raccoons, feral cats and dogs, as well as certain avian
predators such as hawks, owls, herons, jays and egrets, are all known
predators of small mammals (Ingles 1965; J. Maldonado, pers. comm.
1998).
D. The Inadequacy of Existing Regulatory Mechanisms
The primary cause of decline of the Buena Vista Lake shrew is the
loss and fragmentation of habitat due to human activities. Federal,
State, and local laws have not been adequate in preventing destruction
of the limited Buena Vista Lake shrew habitat.
Under section 404 of the Clean Water Act (33 U.S.C. 1344 et seq.),
the U.S. Army Corps of Engineers (Corps) regulates the discharge of
fill material into waters of the United States, including wetlands.
Section 404 regulations require applicants to obtain a permit for
projects that involve the discharge of fill material into waters of the
United States. However, many farming activities do not require a permit
due to their exemption under the Clean Water Act (53 FR 20764; R.
Wayland III, Environmental Protection Agency (EPA), in litt. 1996).
Projects that are subject to regulation may qualify for authorization
to place fill material into headwaters and isolated waters, including
wetlands, under several nationwide permits. Moreover, these projects
can normally be permitted with minimal environmental review by the
Corps. An individual permit may be required by the Corps if a project
otherwise qualifying under a nationwide permit would have greater than
minimal adverse environmental impacts. No activity that is likely to
jeopardize the continued existence of a threatened or endangered
species, or that is likely to destroy or adversely modify the critical
habitat of such species, is authorized under any nationwide permit.
However, the Corps typically confines its evaluation of impacts
only to those areas under its jurisdiction (i.e., wetlands and other
waters of the United States). Impacts to uplands and mitigation for
upland habitat losses are not typically addressed by the Corps unless
such actions affect a listed species. More importantly, the termination
of water sales to the Preserve does not fall under Corps jurisdiction.
The lack of a guaranteed water supply is one of the major reasons TNC
determined that the habitat on the Preserve could not remain viable and
led to TNC's refusal to renew the lease
[[Page 35037]]
and manage the Preserve (S. Phelps, pers. comm. 1995).
The California Environmental Quality Act (CEQA) (Public Resources
Code Sec. 21000-21177) requires a full disclosure of the potential
environmental impacts of proposed projects. The public agency with
primary authority or jurisdiction over a project is designated as the
lead agency and, therefore, is responsible for conducting a review of
the project and consulting with the other agencies concerned with the
resources affected by the project. Section 15065 of the CEQA
Guidelines, as amended, requires a finding of significance if a project
has the potential to ``reduce the number or restrict the range of a
rare or endangered plant or animal.'' Once significant effects are
identified, the lead agency has the option to require mitigation for
effects through changes in the project or to decide that overriding
considerations make mitigation infeasible (CEQA Sec. 21002). In the
latter case, projects may be approved that cause significant
environmental damage, such as destruction of listed endangered species
and/or their habitat. Protection of listed species through CEQA is,
therefore, dependent upon the discretion of the agency involved.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
As stated previously, selenium toxicity represents a serious threat
to the continued existence of the Buena Vista Lake shrew. No cases of
widespread selenium poisoning (selenosis) among native mammals in
nature have been well documented. The lowest dietary threshold for
mammalian toxicity was 1.4 parts per million (ppm) (dry weight) as
associated with sublethal effects from lifetime exposure in rats
(Eisler 1985). Longevity was reduced at 3 ppm in the lifetime diet.
Olson (1986) reports a minimum dietary exposure associated with
reproductive selenosis in rats of 3 ppm. Although stomach content data
for the Buena Vista Lake shrew is lacking, aquatic insects such as
brine flies Diptera ephydridae, damselflies Odonata zygoptera, and
midge flies Diptera chironomidae, have been found in the stomachs of
other shrew species (Churchfield 1991), and could be a dietary source
for the highly insectivorous Buena Vista Lake shrew. Selenium
concentrations have been measured in the above species of flies
collected at agricultural drainage evaporation ponds throughout the
Tulare Basin (Moore et al. 1989). Concentrations of selenium have been
measured from 1.4 to 26.9 ppm (dry weight) in these flies from six
evaporation ponds located a few miles west of the Preserve to the
northern border of the Kern National Wildlife Refuge (Moore et al.
1989). The potential dietary selenium concentration levels are well
within the known range that is toxic to small mammals (Olsen 1986), and
could potentially adversely affect the Buena Vista Lake shrew. Such
effects could include, but may not be limited to, reduced reproductive
output or premature death (Eisler 1985).
Some of the highest selenium levels (greater than 200 parts per
billion) have been measured from ground water throughout the historic
range of the Buena Vista Lake shrew within the Tulare Basin, and
specifically, in evaporation ponds within the agricultural lands
immediately surrounding the only known population of shrews at the
Preserve (DWR 1997). The increased supply of imported water and little
or no exported drain water has resulted in the raising of the ground
water table throughout the Tulare Basin (DWR 1997). Water table levels
have been measured at 1.5 to 3 m (5 to 10 ft) beneath the Preserve and
have steadily moved upwards since 1988 (DWR 1997). As selenium and
other dissolved salts move upward with the elevated water table
(perched water table), the surface vegetation takes up selenium with
the water via root transpiration and enters the food chain of the shrew
by becoming concentrated in insects that forage on the vegetation or
reside in aquifers that concentrate these salts (Saiki and Lowe 1987;
Moore et al. 1989).
Due to the hardpan soil layer beneath the Preserve, the water table
is high and frequently floods despite the installation of tile drains.
In dry years, the water supply is controlled by a single ditch or small
pipe. These unpredictable variables limit the maintenance of suitable
moist habitat for this population of Buena Vista Lake shrews. These
conditions restrict alternative land management practices for shrews on
the Preserve in the event of drought, flooding, harsh winter
conditions, or human-induced environmental impacts.
The only known population of Buena Vista Lake shrews is vulnerable
to the risks associated with small, restricted populations. Impacts to
species populations that can lead to extinction include the loss or
alteration of essential elements, such as habitat or food, the
introduction of limiting factors into the environment, such as poison
or predators, and catastrophic random changes or environmental
perturbations, such as floods, droughts, or disease (Gilpin and Soule
1986). Many extinctions are the result of a severe reduction of
population size by some deterministic event, followed by a random
natural event that extirpates the species. The smaller a population is,
the greater its vulnerability to such perturbations (Terbough and
Winter 1980; Gilpin and Soule 1986; Shaffer 1987). The elements of risk
that are amplified in very small populations include: (1) The impact of
high death rates or low birth rates; (2) the effects of genetic drift
(random fluctuations in gene frequencies) and inbreeding; and (3)
deterioration in environmental quality (Gilpin and Soule 1986). When
the number of individuals in the sole population of a species or
subspecies is sufficiently low, the effects of inbreeding may result in
the expression of deleterious genes in the population (Gilpin 1987).
Deleterious genes reduce individual fitness in various ways, most
typically by decreasing survivorship of young. Genetic drift in small
populations decreases genetic variation due to random changes in gene
frequency from one generation to the next. This reduction of
variability within a population limits the ability of that population
to adapt to environmental changes.
One scenario where loss of habitat may lead to extinction is when
the species is a local endemic (because of its isolation and restricted
range) (Gilpin and Soule 1986). The Buena Vista Lake shrew is a limited
local endemic subspecies (Williams and Kilburn 1992), which has never
been found to be locally abundant, and lives in very restricted areas
of marshy wetland habitat (Bradford 1992). Because the sole population
is small (only 10 known individuals as of 1995) and occurs in a single
small location (12 ha (30 ac)), the Buena Vista Lake shrew is extremely
vulnerable to natural or human-caused environmental impacts. No known
viable populations of Buena Vista Lake shrews exist outside the former
Kern Lake Preserve for recolonization if a catastrophic event were to
occur at this site. While the subspecies still occurs within its
limited range, whether the population is declining, how habitat
conditions may be affecting the population, or how small population
size may be affecting genetic and behavioral stability is unknown.
Based on the vulnerability of this small population in its limited
range and the extremely limited potential for suitable habitat outside
this range, we believe that threats to currently occupied or potential
habitat and individuals put this subspecies at a high risk for
extinction.
In developing this proposed rule, we have carefully assessed the
best
[[Page 35038]]
scientific and commercial information available regarding the past,
present, and future threats facing this subspecies. The Buena Vista
Lake shrew is threatened primarily by agricultural activities,
modifications and potential impacts to local hydrology, uncertainty of
water delivery to the Preserve, possible toxic effects from selenium
poisoning, and by random naturally occurring events. Only one known
population exists, and any decrease in its numbers could result in
decreased genetic variability. Because of the high potential that these
threats, if realized, will result in the extinction of the Buena Vista
Lake shrew, the preferred action is to list the subspecies as
endangered. Not listing the subspecies or listing it as threatened
would not provide adequate protection and would not be consistent with
the Act.
Critical Habitat
Critical habitat is defined in section 3 of the Act as: (i) 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 (I) essential to the conservation
of the species and (II) that may require special management
considerations or protection and; (ii) specific areas outside the
geographical area occupied by a species at the time it is listed, upon
a determination that such areas are essential for the conservation of
the species. ``Conservation'' means the use of all methods and
procedures needed to bring the species to the point at which listing
under the Act is no longer necessary.
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, we designate critical habitat at the time the species
is determined to be endangered or threatened. 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.
We propose that critical habitat is prudent for Sorex ornatus
relictus. In the last few years, a series of court decisions have
overturned Service determinations regarding a variety of species that
designation of critical habitat would not be prudent (e.g., Natural
Resources Defense Council v. U.S. Department of the Interior 113 F. 3d
1121 (9th Cir. 1997); Conservation Council for Hawaii v. Babbitt, 2 F.
Supp. 2d 1280 (D. Hawaii 1998)). Based on the standards applied in
those judicial opinions, we believe that designation of critical
habitat would be prudent for Sorex ornatus relictus.
In the absence of a finding that critical habitat would increase
threats to a species, if any benefits would result from critical
habitat designation, then a prudent finding is warranted. In the case
of this species, designation of critical habitat may provide some
benefits. The primary regulatory effect of critical habitat is the
section 7 requirement that Federal agencies refrain from taking any
action that destroys or adversely modifies critical habitat. While a
critical habitat designation for habitat currently occupied by this
species would not be likely to change the section 7 consultation
outcome because an action that destroys or adversely modifies such
critical habitat would also be likely to result in jeopardy to the
species, in some instances, section 7 consultation might be triggered
only if critical habitat is designated. Examples could include
unoccupied habitat or occupied habitat that may become unoccupied in
the future. Designating critical habitat may also provide some
educational or informational benefits. Therefore, we find that critical
habitat is prudent for the Buena Vista Lake shrew.
As explained in detail in the Final Listing Priority Guidance for
FY 2000 (64 FR 57114), our listing budget is currently insufficient to
allow us to immediately complete all of the listing actions required by
the Act. We plan to employ a priority system for deciding which
outstanding critical habitat designations should be addressed first. We
will focus our efforts on those designations that will provide the most
conservation benefit, taking into consideration the efficacy of
critical habitat designation in addressing the threats to the species,
and the magnitude and immediacy of those threats. Deferral of the
critical habitat designation for the Buena Vista Lake shrew will allow
us to concentrate our limited resources on higher priority critical
habitat and other listing actions, while allowing us to put in place
protections needed for the conservation of the Buena Vista Lake shrew
without further delay. We will make the final critical habitat
determination with the final listing determination for the shrew. If
this final critical habitat determination is that critical habitat
designation is prudent, we will develop a proposal to designate
critical habitat for the Buena Vista Lake shrew as soon as feasible,
considering our workload priorities.
Available Conservation Measures
Conservation measures provided for species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness and
conservation actions by Federal, State, and local agencies, private
organizations, and individuals. The Act provides for possible land
acquisition and cooperation with the States, and requires that recovery
actions be carried out for all listed species. The protection required
by Federal agencies and the prohibitions against certain activities are
discussed, in part, below.
Section 7(a) of the Act, as amended, requires Federal agencies to
evaluate their actions with respect to any species that is proposed or
listed as endangered or threatened, and with respect to its critical
habitat, if any is being designated. Regulations implementing this
interagency cooperation provision of the Act are codified in 50 CFR
part 402. Section 7(a)(2) of the Act requires Federal agencies to
ensure that activities they authorize, fund, or carry out are not
likely to jeopardize the continued existence of a listed species or
destroy or adversely modify its critical habitat. If a Federal action
may affect a listed species or its critical habitat, the responsible
Federal agency must enter into formal consultation with us.
Federal agency actions that may require conference and/or
consultation as described in the preceding paragraph include the U.S.
Army Corps of Engineers and their authorization of projects such as the
construction of drainage diversions, roads, bridges, and dredging
projects subject to section 404 of the Clean Water Act.
The Buena Vista Lake shrew has been included as a candidate species
in the Recovery Plan for Upland Species of the San Joaquin Valley of
California (Recovery Plan) (U.S. Fish and Wildlife Service 1998).
Historically, the Buena Vista Lake shrew was most common in wetland
habitat, and all of its extant and potential habitat is included within
the habitats of the listed species that use alkali sink and associated
communities. Because the subspecies is not federally listed as
endangered or threatened, the recovery actions are identified as
conservation actions and are designed to ensure long-term conservation.
The recovery actions include additional surveys in areas of potentially
suitable
[[Page 35039]]
habitat, habitat restoration and creation on private as well as public
lands, and study of the feasibility of reintroduction at the Tule Elk
State Reserve near Tupman, California. Also identified as needed
conservation actions are population genetic studies, as well as the
continuous monitoring of the only known viable population at the
Preserve.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to all endangered
wildlife. The prohibitions, codified at 50 CFR 17.21, in part, make it
illegal for any person subject to the jurisdiction of the United States
to take (includes harass, harm, pursue, hunt, shoot, wound, kill, trap,
capture, or collect; or to attempt any of these), import or export,
ship in interstate commerce in the course of commercial activity, or
sell or offer for sale in interstate or foreign commerce any endangered
wildlife species. It is also illegal to possess, sell, deliver, carry,
transport, or ship any such wildlife that has been taken illegally.
Certain exceptions apply to our agents and State conservation agencies.
Permits may also be issued to carry out otherwise prohibited
activities involving endangered wildlife under certain circumstances.
Regulations governing permits are codified at 50 CFR 17.22 and 17.23.
Such permits are available for scientific purposes, to enhance the
propagation or survival of the species, and for incidental take in
connection with otherwise lawful activities.
As published in the Federal Register on July 1, 1994 (59 FR 34272)
our policy, to identify to the maximum extent practicable at the time a
species is listed those activities that would or would not constitute a
violation of section 9 of the Act. The intent of this policy is to
increase public awareness of the effect of a proposed listing on
proposed and ongoing activities within a species' range.
We believe that, based on the best available information, the
following actions will not likely result in a violation of section 9,
provided these actions are carried out in accordance with any existing
regulations and permit requirements:
(1) Actions that may affect the Buena Vista Lake shrew that are
authorized, funded, or carried out by a Federal agency, when the action
is conducted in accordance with a biological opinion issued by us
pursuant to section 7 of the Act; and
(2) Actions that may affect the Buena Vista Lake shrew when the
action is a part of an approved habitat conservation plan and conducted
in accordance with an incidental take permit issued by us pursuant to
section 10(a)(1)(B) of the Act.
Activities that we believe could likely result in a violation of
section 9 include, but are not limited to:
(1) Actions not authorized under section 7 or 10 of the Act that
lead to the destruction or alteration of occupied Buena Vista Lake
shrew habitat through the discharge of fill material, draining,
ditching, tiling, pond construction, rock removal, stream
channelization, or diversion of ground water flow into or out of
riparian habitat of this subspecies that are associated with activities
such as the construction or installation of roads, impoundments,
discharge or drain pipes, and storm water detention basins;
(2) Burning, cutting, or mowing of riparian vegetation that results
in death of injury to Buena Vista Lake shrews or that results in
degradation of their occupied habitat;
(3) Application of pesticides that results in death of or injury to
Buena Vista Lake shrews; and
(4) Discharging or dumping toxic chemicals or other pollutants
(such as sewage, oil, or gasoline) that results in death of or injury
to Buena Vista Lake shrews.
Direct your questions regarding whether specific activities may
constitute a violation of section 9 to the Field Supervisor of the
Sacramento Fish and Wildlife Office (see ADDRESSES section). Requests
for copies of the regulations concerning listed wildlife and general
inquiries regarding prohibitions and permits may be addressed to the
U.S. Fish and Wildlife Service, Ecological Services, Endangered Species
Permits, 911 NE. 11th Avenue, Portland, Oregon 97232-4181 (telephone
503/231-2063; facsimile 503/231-6243).
Public Comments Solicited
We intend that any final action resulting from this proposal will
be as accurate and as effective as possible. Therefore, comments or
suggestions from the public, other concerned governmental agencies, the
scientific community, industry, or any other interested party
concerning this proposed rule are hereby solicited. We will follow our
current peer review policy (59 FR 34270) in the processing of this
rule. Comments are sought particularly concerning:
(1) Biological, commercial, or other relevant data concerning any
threat (or lack thereof) to the Buena Vista Lake shrew;
(2) The location of any additional populations of this subspecies
and habitat association (including specific vegetation and soil type),
and the reasons why any habitat should or should not be determined to
be critical habitat as provided by section 4 of the Act;
(3) Additional information concerning the range, distribution, and
population size and genetics of this subspecies;
(4) Current or planned activities in the subject area and their
possible impacts on this subspecies; and
(5) Additional relevant information concerning the life-history,
habits, and dispersal of this subspecies.
A final determination for this subspecies will take into
consideration the comments and any additional information received by
us. Such communications may lead to a final determination that differs
from this proposal.
The Act provides for one or more public hearings on this proposal,
if requested. Requests must be received within 45 days of the date of
publication of the proposal in the Federal Register. Such requests must
be made in writing and addressed to the Field Supervisor, Sacramento
Fish and Wildlife Office (see ADDRESSES section).
National Environmental Policy Act
We have determined that environmental assessments and environmental
impact statements, as defined in the National Environmental Policy Act
of 1969, need not be prepared in connection with regulations adopted
pursuant to section 4(a) of the Act. We published a notice outlining
our reasons for this determination in the Federal Register on October
25, 1983 (48 FR 49244).
Paperwork Reduction Act
This rule does not contain any new collections of information other
than those already approved under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq., and assigned Office of Management and Budget
clearance number 1018-0094. An agency may not conduct or sponsor, and a
person is not required to respond to, a collection of information
unless it displays a currently valid control number. For additional
information concerning permit and associated requirements for
endangered species, see 50 CFR 17.21 and 17.22.
References Cited
A complete list of all references cited herein is available upon
request from the Field Supervisor, Sacramento Fish
[[Page 35040]]
and Wildlife Office (see ADDRESSES section).
Author
The primary author of this proposed rule is Dwight Harvey, U.S.
Fish and Wildlife Service, Sacramento Fish and Wildlife Office (see
ADDRESSES section).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulations Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
1. The authority citation for part 17 continues to read as follows:
Authority: 6 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; Pub. L. 99-625, 100 Stat. 3500, unless otherwise noted.
2. Section 17.11(h) is amended by adding the following, in
alphabetical order under ``MAMMALS,'' to the List of Endangered and
Threatened Wildlife:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate
-------------------------------------------------------- population where Critical Special
Historic range endangered or Status When listed habitat rules
Common name Scientific name threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mammals
* * * * * * *
Shrew, Buena Vista Lake.......... Sorex ornatus U.S.A. (CA)........ Entire............. E 699 NA NA
relictus.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dated: May 16, 2000.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 00-13706 Filed 5-31-00; 8:45 am]
BILLING CODE 4310-55-P