[Federal Register: March 25, 1999 (Volume 64, Number 57)] [Proposed Rules] [Page 14424-14428] From the Federal Register Online via GPO Access [wais.access.gpo.gov] [DOCID:fr25mr99-44] ======================================================================= ----------------------------------------------------------------------- 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