[Federal Register Volume 64, Number 57 (Thursday, March 25, 1999)]
[Proposed Rules]
[Pages 14424-14428]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-7273]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 90-day Finding for
a Petition To List the Black-Tailed Prairie Dog as Threatened
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding.
-----------------------------------------------------------------------
SUMMARY: We have received a petition to list the black-tailed prairie
dog (Cynomys ludovicianus) throughout its range in Arizona, Colorado,
Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South
Dakota, Texas, Wyoming, southern Saskatchewan, Canada, and northern
Mexico. The petition presents substantial scientific and commercial
information that the request for listing may be warranted. Therefore,
we are initiating a status review to determine if the petitioned action
is warranted. To ensure that the review is comprehensive, we are
soliciting information and data regarding this action. We will use
information received during the comment period for this status review
in our review of the black-tailed prairie dog.
DATES: The finding announced in this document was made on March 17,
1999. A status review is initiated. To have
[[Page 14425]]
information considered in the status review and subsequent 12-month
finding for the petition, submit information to us by May 24, 1999.
ADDRESSES: Data, information, technical critiques, comments, or
questions relevant to this finding should be submitted to the Field
Supervisor, Ecological Services, U.S. Fish and Wildlife Service, 420
South Garfield Avenue, Suite 400, Pierre, South Dakota 57501-5408. You
may inspect the petition, finding, and supporting documents, by
appointment, at the above address. You may request and receive
electronic copies of the petition and finding via e-mail from
r6fwe__pie@fws.gov.
FOR FURTHER INFORMATION CONTACT: Pete Gober, at the address given
above, or telephone (605) 224-8693.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Endangered Species Act (Act) of 1973 as
amended (16 U.S.C. 1531 et seq.), requires us to make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial scientific and commercial information to demonstrate that
the petitioned action may be warranted. This finding is to be based on
all information available to us at the time we make the finding. To the
maximum extent practicable, we make this finding within 90 days of
receipt of the petition and we promptly publish a Notice in the Federal
Register. This document provides a summary of the information in the
90-day finding, which is our decision document. When we make a positive
finding, we are required to promptly initiate a status review of the
species. A positive 90-day finding is not a decision to list a species.
This document meets the requirement for publication of a 90-day finding
on the petition discussed below.
We have made a 90-day finding on a petition to list the black-
tailed prairie dog (Cynomys ludovicianus). The petition, dated July 30,
1998, was submitted by Thomas France, Esq., and Dr. Sterling Miller,
both of Missoula, Montana, and Kimberly Graber, Esq., of Denver,
Colorado, on behalf of the National Wildlife Federation (NWF; ``the
Petitioners''), and was received by us on July 31, 1998, accompanied by
a letter from Mark Van Putten, Chief Executive Officer for NWF. The
Petitioners requested that we list the black-tailed prairie dog as a
threatened species throughout its range. The Petitioners also requested
that the black-tailed prairie dog receive emergency listing under the
Act.
We received another petition regarding the same species from the
Biodiversity Legal Foundation, the Predator Project, and Jon C. Sharps
on August 26, 1998. They requested that we list the black-tailed
prairie dog as threatened throughout its known historic range in the
contiguous United States. We accepted this second request as
supplemental information to the NWF petition.
The Petitioners presented extensive information regarding the
biology and ecology of the black-tailed prairie dog. The Petitioners
and other interested parties also provided supplemental information to
the NWF petition that has been considered in this finding.
Additionally, we have reviewed information in our files, other readily
available information, and information submitted by Federal, State, and
Tribal agencies. We expect to solicit and receive additional
information through the status review of the species.
The Petitioners expressed concern about continuing human activities
that pose a threat to the black-tailed prairie dog and additional
threats that might be anticipated following the filing of their
petition. The Petitioners predicted that poisoning and shooting
activities would increase and result in significant population declines
for the species during the normal rulemaking process. Thus, the
petitioners requested that we emergency list the black-tailed prairie
dog. Under 16 U.S.C. 1533(b)(7), the Secretary of the Interior has the
authority to suspend normal rulemaking procedures and issue emergency
regulations for a species, when there is a significant risk to the
species and where the routine listing process is not adequate to
prevent losses that may result in extinction. We determined, and
advised the Petitioners, that based on our initial review of the
petition, it would be inappropriate to emergency list this species
based on its current known status. Furthermore, it is typically
inappropriate to emergency list a species as threatened because the
threatened definition only covers species that are at risk of becoming
endangered, not extinct. We acknowledged that existing regulatory
mechanisms for black-tailed prairie dogs may not preclude continued
losses of individuals from some populations of the species. However, we
believe that the normal petition review and rulemaking procedures are
sufficient and appropriate. We will revisit the issue of emergency
listing if the immediacy or magnitude of threats increase such that
black-tailed prairie dogs require immediate protection.
The historical range of the black-tailed prairie dog includes
southern Saskatchewan, Canada; eastern Montana, Wyoming, Colorado, and
New Mexico; western North Dakota; western and central South Dakota,
Nebraska, Kansas, and Oklahoma; western, northwestern, and northern
Texas; and northeastern Mexico (Miller et al. 1996). The species was
present historically in eastern Arizona, but was extirpated in recent
years (Alexander 1932). The Petitioners noted that the species still
occurs generally throughout its historic range, although much reduced
in numbers and in the amount of habitat that it occupies. The
Petitioners asserted that the black-tailed prairie dog once occupied
more than 100 million acres (ac) or 40 million hectares (ha) of western
North America, contrasted that with current estimates of occupied
habitat (Knowles 1998a), and concluded that the species' population has
been reduced by 99 percent. The Petitioners attributed reductions in
occupied habitat to habitat loss and degradation related to the
conversion of prairie grasslands to farmland, urban development,
extensive poisoning efforts, unregulated shooting, disease,
combinations of these factors, and other causes.
The Petitioners asserted that the small size and widely spaced
distribution of most remaining black-tailed prairie dog colonies create
concerns of adverse influences of habitat fragmentation, dispersal
limitations, and other factors. They asserted that the cumulative
effect of these factors is to reduce the viability of the species and
increase the probability of extinction for the species. They
acknowledged that the number of individual black-tailed prairie dogs
appears to be comparable to many other species that are not thought to
be in danger of extinction. However, they argued that the species is
threatened as evidenced by (and due to) its precipitous historic
population decline, its recent population declines, and the number and
variety of threats to it. The Petitioners emphasized the colonial
nature of the black-tailed prairie dog and the subsequent population
responses en masse to habitat conversion, poisoning efforts, and
especially disease (i.e., sylvatic plague, a disease exotic to North
America and to which prairie dogs have no immunity).
The Petitioners pointed out that all States within the range of the
black-tailed prairie dog have classified it as a pest for agricultural
purposes, either permitting or requiring eradication of the species.
They also asserted that these States allow or promote unlimited
[[Page 14426]]
recreational shooting. The Petitioners believed that there are
inconsistent Federal policies regarding all species of prairie dogs,
and that the legal mechanisms under which they have declined remain in
place. The Petitioners asserted that some Tribes have a sophisticated
management program for the black-tailed prairie dog and play an
important role in its conservation.
We have previously addressed the status of the black-tailed prairie
dog. On October 21, 1994, the Biodiversity Legal Foundation and Jon C.
Sharps petitioned us to classify the black-tailed prairie dog as a
Category 2 candidate species pursuant to the Administrative Procedures
Act and the ``intent of the Endangered Species Act'' (Biodiversity
Legal Foundation and Sharps 1994). At that time a Category 2 candidate
species was a taxon for which we believed listing might be appropriate,
but for which there was not sufficient data regarding biological
vulnerability or threats to support a proposed rule. We no longer use
this candidate classification system. The addition of a species to the
list of Category 2 candidates was not an action petitionable under the
Act. However, we reviewed the status of the black-tailed prairie dog in
1994-1995 and concluded that the numbers, distribution, and
reproductive capability of the species were such that it did not
warrant candidate status at that time (Terrell, U.S. Fish and Wildlife
Service, in litt. 1995). New information has become available since
then and we believe that an additional status review is now
appropriate.
Black-tailed prairie dogs are small, stout, ground squirrels
approximately 14-17 inches (in) long and weighing 1-3 pounds (lbs).
Black-tailed prairie dogs are highly social colonial, diurnal,
burrowing animals. Individual appearance within the species varies with
a mix of brown, black, gray, and white, but with a characteristic
black-tipped tail (Hoogland 1995). The black-tailed prairie dog is a
colonial ground squirrel and one of five species in the genus Cynomys,
all of which occur in western North America. There are two subspecies
of the black-tailed prairie dog--the Arizona black-tailed prairie dog
(C. l. arizonensis), and the more widespread black-tailed prairie dog
(C. l. ludovicianus) (Hall and Kelson 1959), which is usually what is
thought of when the common name ``black-tailed prairie dog'' is used.
Historical and Current Distribution
The Arizona subspecies (C. l. arizonensis) is found in northeastern
Mexico (Ceballos et al. 1993), is extirpated (extinct) in Arizona
(Alexander 1932), may or may not be present in New Mexico, and is
remnant in west Texas (Davis 1974; Hall and Kelson 1959). Individuals
of this subspecies in Chihuahua, Mexico, comprise the largest prairie
dog complex (90,000 ac or 36,000 ha) remaining in North America. This
complex is the only significant population remaining in Mexico
(Ceballos et al. 1993). The black-tailed prairie dog is listed as
threatened by the Lista de las Especies Amerzadas, the official
threatened and endangered species list of the Mexican Government
(SEMARNAP 1994).
The major subspecies, C. l. ludovicianus, is found in Montana,
Wyoming, Colorado, New Mexico, North Dakota, South Dakota, Nebraska,
Kansas, Oklahoma, northern Texas, and Canada. In Canada, the black-
tailed prairie dog is designated as vulnerable by the Committee on the
Status of Endangered Wildlife in Canada. In the remainder of this
finding, the name ``black-tailed prairie dog'' will be used to include
both subspecies.
In addition to the large colony in Mexico, we know of only six
other black-tailed prairie dog colonies larger than 10,000 ac (4,000
ha) remaining throughout the species' range--one in Montana, one in
Wyoming, and four in South Dakota. South Dakota, the only State where
plague is absent, contains an estimated 32 percent of the remaining
black-tailed prairie dog occupied habitat. All other remaining black-
tailed prairie dog colonies are smaller, more isolated, and spottily
distributed throughout the species range.
Rangewide, the black-tailed prairie dog is estimated to inhabit
only a small fraction of the area that it once occupied, perhaps as
little as 800,000 ac (320,000 ha) (Knowles 1998a) of what may have been
300 million ac or more (120 million ha) in its original range (Seton
1953). Seton (1953) estimated that individuals of black-tailed prairie
dogs once numbered 5 billion. Many prairie dog colonies were quite
large and interconnected (Miller et al. 1996). By 1961, the area
occupied by black-tailed prairie dogs in the United States had declined
to approximately 364,000 ac (147,000 ha) (Bureau of Sport Fisheries and
Wildlife 1961). Knowles (1998a), Weurthner (1997), Barko (1997),
Knowles (1995), Mulhern and Knowles (1995), and Fagerstone and Ramey
(1995) concluded that an approximate decrease in area occupied of 94-99
percent had occurred compared to historic estimates. Generally, State
wildlife agencies confirm this decline, but some point out that
disproportionately more occupied habitat remains in some areas than in
others. Knowles' (1998a) estimated that 677,000 ac (274,000 ha) of
black-tailed prairie dog occupied habitat in the United States remains.
Some increases in black-tailed prairie dog occupied habitat occurred in
1961-1980 (notably in Wyoming and South Dakota), but in 1980-1998,
significant declines occurred in Montana, Mexico, and South Dakota.
Three major impacts have had substantial influence on black-tailed
prairie dog populations and distribution. The petitioners asserted that
the first major impact on the species historically was the conversion
of prairie grasslands to farmland in the eastern portion of its range,
and that the second major impact on the species was large-scale
poisoning conducted to reduce perceived competition between prairie
dogs and domestic livestock. A third major impact on the species was
the inadvertent introduction of an exotic disease from the Old World,
sylvatic plague, into the North American prairie ecosystem. Other
authors also address these threats to the black-tailed prairie dog, as
discussed below.
Threats
A. The Present or Threatened Destruction, Modification, or Curtailment
of the Species' Habitat or Range
The petitioners asserted that conversion of prairie habitat to
farmland was one of the primary causes of the decline in occupied
habitat of the black-tailed prairie dog. Between 1880 and 1899, 104
million ac (42 million ha) of the total western plains surface area was
converted to crop productions (Laycock 1987). Native grasslands have
been reduced by approximately 60 percent (Burke in prep.) resulting in
significant destruction of black-tailed prairie dog habitat. Some
agricultural conversion of native grasslands continues today, and could
accelerate with the increase of dryland cropping and use of genetically
engineered drought resistant crop strains. Hexem and Krupa (1987)
identified 57,700,000 ac (23,400,000 ha) of unplowed land in the
western Great Plains with potential for cropland conversion. Such
conversion could significantly reduce the remaining native prairie and
black-tailed prairie dog habitat.
Urbanization also presents a significant loss of black-tailed
prairie dog habitat in local areas near metropolitan areas such as
Wichita,
[[Page 14427]]
Kansas; Helena, Montana (Knowles 1995); and the Front Range of Colorado
near Denver (Weber, Colorado Division of Wildlife, pers. comm. 1998).
Habitat loss also occurs through degradation of burrows and vegetation
changes in areas where black-tailed prairie dogs have been removed.
Once underground burrows collapse or there is an increase in woody or
taller vegetation, the species is less likely to reestablish itself in
the area. At the Rocky Mountain Arsenal National Wildlife Refuge in
Colorado, reintroduced black-tailed prairie dogs reestablished
themselves quickly where intact burrows constructed by previous prairie
dogs (extirpated by sylvatic plague) had not deteriorated (Seery, U.S.
Fish and Wildlife Service, pers. comm. 1998). Where burrows had
deteriorated, prairie dogs established themselves slowly and with
little success. Weltzin et al. (1997) determined that historically,
black-tailed prairie dogs, and the herbivores and granivores associated
with their colonies, probably maintained grassland and savanna by
preventing woody species such as mesquite from establishing or
attaining dominance. List (1997) reported that poisoning of black-
tailed prairie dogs in Mexico resulted in the invasion of mesquite
shrubs that rendered the landscape unsuitable for reoccupation by the
species; moreover, fire suppression would likely maintain this
situation. Davis (1974) also noted that removal of the species from
some sites in Texas resulted in the invasion of brush. Thus, when
degradation of burrows or vegetation changes occur, the amount of
habitat suitable for recolonization may be reduced. Current levels of
conversion of rangeland to farmland or urban development may not be as
important to the species' numbers and viability as are indirect losses
caused by poisoning or disease. These indirect losses of individuals or
local populations may result in habitat loss for the species through
the deterioration of burrows and the alteration of vegetative
communities.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
One activity impacting black-tailed prairie dog populations in some
local areas is unregulated recreational (sport or varmint) shooting.
Shooting has increased appreciably in popularity in recent years. An
example of this is the Buffalo Gap National Grasslands in South Dakota
where the number of annual shooter days has increased from a few
hundred in the mid-1990's to an estimated 6,500 in 1998 (Perry, U.S.
Forest Service, pers. comm., 1998). High-powered rifles with high-
quality scopes enable the modern varmint shooter to be consistently
accurate at distances of 400 yards (yd) (400 meters (m)) or greater,
and an individual shooter may shoot a considerable number of animals
each day (Kayser 1998). Many States do not require hunting licenses and
have no bag limits or seasonal restrictions for taking prairie dogs.
Prairie dog density may decrease with increased shooting pressure and
prairie dogs may spend more time on alert and less time foraging
(Vosberg 1996). Shooting also may contribute to population reduction
and fragmentation, reduce colony productivity and health, and preclude
or delay recovery of colonies reduced by other factors such as sylvatic
plague. Recreational shooting may significantly impact colonies in
local areas where shooting is most intense or colony numbers are
already reduced from other losses.
C. Disease or Predation
Sylvatic plague is a non-native disease caused by the bacterium,
Yersinia pestis, which fleas can harbor and transmit to rodents and
other species (Cully 1989). The term ``sylvatic'' refers to the
occurrence of the disease in the wild (Berkow 1982). Barnes (1993)
recorded sylvatic plague in 76 species of 6 mammalian orders, although
it is primarily a rodent disease. Rodent species vary in their
susceptibility to plague, with some species acting as hosts or carriers
of the disease or infected fleas and showing no symptoms (e.g.,
kangaroo rats, Dipodomys sp., and deer mice, Peromyscus maniculatus).
Conversely, black-tailed and Gunnison's prairie dogs show nearly 100
percent mortality when exposed to sylvatic plague (Barnes 1993, Cully
1993).
Sylvatic plague is an exotic disease foreign to the evolutionary
history of North American species. Scientists discovered the plague
among wild rodents near San Francisco in 1908 and it has spread
throughout much of the Great Plains over the past century (Eskey and
Haas 1940, Miles et al. 1952 in Cully 1989, Ecke and Johnson 1952).
Black-tailed prairie dogs show neither effective antibodies nor
immunity to the disease. Death occurs quickly for prairie dogs exposed
to sylvatic plague; noticeable symptoms usually do not develop (Cully
1993). Data obtained from the Rocky Mountain Arsenal National Wildlife
Refuge show that plague has the potential to severely depress black-
tailed prairie dog populations and cause local extirpations (Seery and
Matiatos, in press; U.S. Fish and Wildlife Service 1998). Scientists
have also observed longterm plague-related declines in white-tailed
prairie dogs near Meeteetse, Wyoming (Biggins, U.S. Geological Survey,
Biological Resources Division, pers. comm. 1998).
Many mammals, snakes, and raptors prey on prairie dogs (Hoogland
1995) and the species has evolved resilience to natural levels of
predation. Scientists do not generally see predation as a threat to the
species but, in unusual circumstances intense levels of predation may
be problematic to individual small colonies, particularly if they are
already reduced by other causes.
D. The Inadequacy of Existing Regulatory Mechanisms
All States within the historic range of the black-tailed prairie
dog classify the species as a pest for agricultural purposes and either
permit or require their eradication (Mulhern and Knowles 1995). Fish
and wildlife agencies in many States classify black-tailed prairie dogs
by categories such as ``unclassified game'' that permit licensed or
unlicensed shooting with no limitations on take or season. Knowles
(1995) reviewed Federal regulatory management policies as they relate
to the black-tailed prairie dog. Significant black-tailed prairie dog
occupied habitat is found on public lands managed by the BIA, the
Bureau of Land Management (BLM), the Service, USFS, and the National
Park Service (NPS). The BLM manages prairie dogs to meet multiple-use
resource objectives (Knowles 1995). Various National Forest Resource
Management Plans address black-tailed prairie dog habitat on USFS-
administered land; these plans reflect Forest Service policy, not
regulation. Two tribes have voluntary prairie dog management plans in
place (Knowles 1995). In areas where black-footed ferrets are re-
established, some programs to conserve prairie dogs are in place.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Control (Poisoning)
Hanson (1993) cited poisoning as a major factor in the reduction of
prairie dog populations. An extensive poisoning effort has occurred
over most of the species' range (Bell 1921, Cain et al. 1971, Anderson
et al. 1986, Roemer and Forrest 1996, and Forrest and Proctor in
prep.). Organized prairie dog control gained momentum from 1916 to
1920, when property owners and Federal agencies poisoned prairie dogs
[[Page 14428]]
on millions of acres of western rangeland (Bell 1921); Federal programs
were responsible for much of this effort. From 1937-1968, 30,447,355 ac
(12,321,875 ha) of occupied prairie dog habitat was controlled (Cain et
al. 1971). After the 1970's some toxicants previously used for prairie
dog control were banned and although prairie dog control continued, it
occurred at a reduced rate.
Federal agencies are involved to varying degrees in active control
of prairie dog colonies. The Environmental Protection Agency regulates
use of prairie dog poisons. The Animal and Plant Health Inspection
Service-Wildlife Services (APHIS-WS) provides technical assistance and
distributes prairie dog poison to State and Federal agencies, Tribes,
and private landowners. Based on information obtained from the APHIS
Freedom of Information Act web page (foia.aphis.usda.gov), the agency
controlled 95,076 ac (38,480 ha) of black-tailed prairie dog habitat
from 1991-1996. Although this number could have included some acreage
that was treated more than once, this number indicates that over a 5-
year period, AHPIS-WS alone has conducted prairie dog control on 14
percent of the estimated remaining black-tailed prairie dog habitat.
Control programs have significantly reduced black-tailed prairie
dog populations. These programs essentially remove all animals from the
area treated and directly contribute to habitat fragmentation and
vegetation changes that limit future recolonization by the black-tailed
prairie dog. In particular, Federal control programs may play a
significant role in the continued decline of black-tailed prairie dog
populations.
Habitat Fragmentation
The grassland biome in North America has arguably suffered the most
extensive fragmentation and transformation of any biome on the
continent (Groombridge 1992). More fragmented, more isolated, and less
connected populations usually have higher extinction rates (MacArther
and Wilson 1967, Wilcox and Murphy 1985, Clark 1989). Miller et al.
(1996) describe existing prairie dog populations as small, disjunct,
and geographically isolated. They further describe the discontinuous
nature of remaining populations as widely separated islands where
habitat fragmentation has increased the likelihood of individual colony
extinction due to genetic inbreeding and random demographic events.
Lost genetic diversity is inherently detrimental to most species.
Black-tailed prairie dog dispersal movements that previously offset
these adverse effects likely are limited by short migration distances,
as reported by Hoogland (1995) and Knowles (1985), and longer distances
between remaining colonies.
Finding
We have reviewed the petition, as well as other available
information, published and unpublished studies and reports, information
received from State, Tribal and private entities, and agency files. On
the basis of our review of the petition, literature cited in the
petition, and other readily available information, we find there is
sufficient information to indicate that listing of the black-tailed
prairie dog may be warranted, and we initiate a status review. However,
we also find there is no substantial information to warrant an
emergency listing at this time, as was requested by the petitioner.
Based on our review of the petition and other readily available
information, we believe that the decline, especially the recent
decline, of the black-tailed prairie dog likely is due to many factors.
One of the most influential and unpredictable factors is the widespread
occurrence of plague, an exotic and completely lethal disease to the
species. We believe that we should evaluate black-tailed prairie dog
reduced colony size and connectivity in light of factors such as
plague, control, land conversion, and shooting, in a thorough analysis
of the status of the species. Therefore, with the completion of this
90-day Finding, a status review of the species will be undertaken with
a subsequent Finding as to whether the petitioned action is warranted
(section 4(b)(3)(B) of the Act). We will consider all relevant
information in conducting a full status review to determine if listing
is warranted. We are hereby requesting any additional data or
scientific information from the public, scientific community, Tribal,
State and Federal governments, and other interested parties concerning
the status of and threats to the black-tailed prairie dog throughout
the species' range.
References Cited
You may request a complete list of all references cited herein, as
well as others, from the Service's Pierre Field Office (see ADDRESSES
section).
Author
Pete Gober (see ADDRESSES section) prepared this document.
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531-1544 et seq.).
Dated: March 17, 1999.
Jamie Rappaport Clark,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 99-7273 Filed 3-23-99; 8:45 am]
BILLING CODE 4310-55-P
