Endangered and Threatened Wildlife and Plants: 12-month Finding on a Petition To List the White-tailed Prairie Dog as Endangered or Threatened

Federal Register: June 1, 2010 (Volume 75, Number 104)

Proposed Rules

Page 30338-30363

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

DOCID:fr01jn10-29

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service 50 CFR Part 17

Docket No. FWS-R6-ES-2008-0053

MO 92210-0-0008-B2

Endangered and Threatened Wildlife and Plants; 12-month Finding on a Petition to List the White-tailed Prairie Dog as Endangered or

Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of a 12-month petition finding.

SUMMARY: We, the U.S. Fish and Wildlife Service announce a 12-month finding on a petition to list the white-tailed prairie dog (Cynomys leucurus) as endangered or threatened under the Endangered Species Act of 1973, as amended. After a review of all available scientific and commercial information, we find that listing the white-tailed prairie dog is not warranted at this time. However, we ask the public to submit to us any new information that becomes available concerning the threats to the white-tailed prairie dog or its habitat at any time.

DATES: The finding announced in this document was made on June 1, 2010.

ADDRESSES: This finding is available on the Internet at http:// www.regulations.gov at Docket Number FWS-R6-ES-2008-0053. Supporting documentation we used in preparing this finding is available for public inspection, by appointment, during normal business hours at the U.S.

Fish and Wildlife Service, Utah Field Office, 2369 West Orton Circle,

Suite 50, West Valley City, UT 84119. Please submit any new information, materials, comments, or questions concerning this finding to the above street address.

FOR FURTHER INFORMATION CONTACT: Larry Crist, Field Supervisor, Utah

Field Office (see ADDRESSES); by telephone at 801-975-3330; or by facsimile at 801-975-3331. If you use a telecommunications device for the deaf (TDD), please call the Federal Information Relay Service

(FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(B) of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition to revise the Federal Lists of Endangered and Threatened Wildlife and

Plants that contains substantial scientific or commercial information that listing the species may be warranted, we make a finding within 12 months of the date of receipt of the petition. In this finding, we will determine that the petitioned action is: (1) Not warranted, (2) warranted, or (3) warranted, but the immediate proposal of a regulation implementing the petitioned action is precluded by other pending proposals to determine whether species are endangered or threatened, and expeditious progress is being made to add or remove qualified species from the Federal Lists of Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires that we treat a petition for which the requested action is found to be warranted but precluded as though resubmitted on the date of such finding, that is, requiring a subsequent finding to be made within 12 months. We must publish these 12-month findings in the Federal Register.

Previous Federal Action

On July 15, 2002, we received a petition dated July 11, 2002, from the Center for Native Ecosystems, Forest Guardians, Biodiversity

Conservation Alliance, and Terry Tempest Williams, requesting that the white-tailed prairie dog (Cynomys leucurus) be listed as endangered or threatened across its entire range. We acknowledged the receipt of the petition in a letter to the petitioners, dated August 27, 2002. In that letter we also stated that higher priority actions precluded addressing the petition immediately, but it would be addressed when funding allowed.

Section 4(b)(3)(B) of the Act requires that for any petition to revise the Lists of Threatened and Endangered Wildlife and Plants, to the maximum extent practicable, within 90 days after receiving the petition, we make a finding as to whether the petition presents substantial scientific or commercial information indicating that the petitioned action may be warranted. On November 9, 2004, we announced our 90-day finding (69 FR 64889) that the petition did not present substantial scientific or commercial information indicating that listing may be warranted. On July 12, 2007, in a Director's memorandum, the U.S. Fish and Wildlife Service (Service) announced that we would review the November 9, 2004, finding after questions were raised about the integrity of scientific information used and whether the decision was consistent with the appropriate legal standards. We received notice of a lawsuit from the Center for Native Ecosystems, and three other entities, on November 27, 2007, regarding our not-substantial 90-day finding. We agreed in a stipulated

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settlement agreement on February 22, 2008, to submit a notice initiating a 12-month finding for the white-tailed prairie dog to the

Federal Register on or before May 1, 2008, and to submit a 12-month finding for the white-tailed prairie dog to the Federal Register on or before June 1, 2010. Due to the stipulated settlement agreement, the petitioners dismissed the lawsuit on February 26, 2008. This notice constitutes the 12-month finding under the stipulated settlement agreement on the petition to list the white-tailed prairie dog as endangered or threatened.

Species Information

Species Description

White-tailed prairie dogs are between 340 to 370 millimeters (mm)

(13.4 to 14.6 inches (in)) in length with a 40- to 65-mm (1.6- to 2.6- in) long tail (Clark et al. 1971, p. 1). The tail has a grayish white tip and is white on the terminal half. The coat is generally yellow-tan with distinctive dark brown or black cheek patches that extend above the eye with a lighter black stripe that extends below the eye onto the cheek (Clark et al. 1971, p. 1).

Taxonomy

The white-tailed prairie dog is one of five prairie dog species that inhabit western North America (Clark et al. 1971, p. 1; Pizzimenti 1975, pp. 62-63). Prairie dogs are in the squirrel family, Sciuridae, and belong to the genus Cynomys (Hollister 1916, p. 5). The genus is split into two subgenera; Leucocrossuromys includes prairie dogs with white tails and Cynomys includes prairie dogs with black tails. White- tailed prairie dogs are included in the subgenus Leucocrossuromys along with Utah and Gunnison prairie dogs (Clark et al. 1971, p. 1;

Pizzimenti 1975, pp. 15-16). Due to this consensus, we determined that the white-tailed prairie dog is a valid taxonomic species and a listable entity under the Act.

Ecology and Life History

White-tailed prairie dogs occur at elevations ranging from 1,150 meters (m) (3,773 feet (ft)) (Flath 1979, p. 63) to 3,200 m (10,500 ft)

(Tileston and Lechleitner 1966, p. 295). Unlike the grass-dominated habitats of black-tailed prairie dogs, white-tailed prairie dogs inhabit drier landscapes with shrubland vegetation (Tileston and

Lechleitner 1966, p. 295; Clark 1977, pp. 3-5; Collins and Lichvar 1986, pp. 88-91; Gadd 2000, pp. 15-16). Their habitats are generally flat (Collins and Lichvar 1986, p. 92).

Prairie dogs are primarily herbivorous and mainly eat grasses and forbs (Kelso 1939, pp. 7-11). However, they consume other plants seasonally. Prairie dog selection of plants is somewhat dependent on site-specific conditions and seasonality. For example, white-tailed prairie dogs eat sagebrush and saltbush during early spring, grasses in the summer, and seed heads and rabbitbrush flowers in the fall (Kelso 1939, p. 10; Tileston and Lechleitner 1966, p. 302). White-tailed prairie dogs eat the least amount of grass of any prairie dog species and the most saltbush (Kelso 1939, p. 11). White-tailed prairie dogs also eat insects (Stockard 1929, p. 476). Prairie dogs obtain most of their water by eating vegetation and can become water-stressed if sufficient succulent vegetation is unavailable (Seglund et al. 2006, p. 7).

White-tailed prairie dogs prefer areas with lower vegetation heights (Collins and Lichvar 1986, p. 92), but they may use dense sagebrush adjacent to grassier areas (Tileston and Lechleitner 1966, p. 314). White-tailed prairie dogs use the dense vegetation within sagebrush habitat to hide from predators (Hoogland 1981, pp. 266-268;

Gadd 2000, pp. 24-26), reducing their need to visually search for predators and consequently reducing their need for dense colonies and cohesive social structures. This habitat use differs from black-tailed prairie dogs, who actively work to maintain the grassland vegetation surrounding their burrows for visibility.

White-tailed prairie dogs dig their own burrows. Burrow construction requires deep, well-drained soils. Preferred soils are derived from sandstone or shale and may be clay-loam, silty clay, or sandy loam (Lupis et al. 2007, p. 6). Burrows are used throughout the year for hibernation, cover from temperature extremes, predator avoidance, and birthing and raising young (Clark 1977, p. 9; Hoogland 1981, pp. 258-264). Burrow complexes are usually widespread with numerous entrances, tunnels, and chambers. The number of burrows in an area varies greatly from location to location, ranging from 0.12 to 47.75 per hectare (ha) (0.3 to 118 per acre (ac)) with a mean of 0.32 to 6.79 per ha (0.8 to 16.8 per ac) (Tileston and Lechleitner 1966, p. 314; Menkens and Anderson 1989, p. 84; Seglund and Schnurr 2009, p. 94).

For purposes of this finding, a group of burrows is referred to as a colony. A complex is a collection of colonies grouped on the landscape. There is usually a high degree of connectivity between colonies in the same complex.

White-tailed prairie dog colonies have fewer animals per unit area with less obvious borders than black-tailed prairie dog colonies

(Tileston and Lechleitner 1966, pp. 297, 314; Hoogland 1981, p. 252).

Home range sizes range from 0.2 to 1.9 ha (0.5 to 4.7 ac) (Clark 1977, p. 65; Cooke 1993, p. 23), which are generally larger than black-tailed prairie dog home ranges (Clark 1977, p. 65).

White-tailed prairie dogs can live up to 8 years in captivity but may not live past 4 years in the wild (Pauli et al. 2006, p. 18).

Prairie dog annual mortality rates average 30 to 60 percent, largely due to disease and predation (Tileston and Lechleitner 1966, p. 305;

Clark 1977, pp. 80-81).

Adult sex ratios are approximately one male to two females (Clark 1977, p. 76; Hoogland 2010, pers. comm.). White-tailed prairie dogs can reproduce at 1 year of age, and they have a single litter once a year averaging four to five pups (Bakko and Brown 1967, pp. 110-111).

Breeding occurs from late March to mid-April (Tileston and Lechleitner 1966, p. 303). Pups are born in the burrows after a gestation period of approximately 30 days (Tileston and Lechleitner 1966, p. 304), and emerge from the burrow for the first time 4 to 6 weeks after birth

(Bakko and Brown 1967, p. 103). They begin to disperse from the colony in June and July when population densities are the highest (Clark 1977, p. 72). Migration is recognized as an important factor to white-tailed prairie dog population dynamics (Clark 1977, p. 80). Plague in this species often results in near extirpation of colonies. Rapid recolonization of some areas post-plague with few or no surviving reproductive adults suggests the species is highly mobile (Seglund et al. 2006, p. 10). Dispersal distances of up to 8 kilometers (km) (4.8 miles (mi)) have been observed (Cooke 1993 in Seglund et al. 2006, p. 10)

White-tailed prairie dogs have the least cohesive social structure of any prairie dog species. Their social system is organized around family groups or ``clans,'' comprised of several reproductive females, one or two males of reproductive age, and dependent young (Clark 1977, p. 62; Cooke 1993, p. 22). Adult white-tailed prairie dogs spend little time displaying social behavior, and most of their time feeding or in alert postures (Clark 1977, p. 44). Pups spend a large amount of time playing during their first few weeks (Tileston and Lechleitner 1966, p. 300).

White-tailed prairie dog populations exhibit large fluctuations of more than

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50 percent from year to year (Menkens and Anderson 1989, p. 345).

Population fluctuations are likely due to disease cycles, vegetation quantity and quality, and drought (Seglund and Schnurr 2009, p. 16)

(see Factor A. Climate Change; Factor C. Disease). We do not know the level at which population fluctuations are a natural part of white- tailed prairie dog ecology, or the result of environmental or human- caused threat factors. In many cases, prairie dog colonies persist despite large population fluctuations (see Factor C. Disease). We define ``persistence'' as the long-term continuance of white-tailed prairie dog colonies, at a high enough level to exist in the long-term with minimal management assistance.

White-tailed prairie dogs are diurnal (active during the day)

(Tileston and Lechleitner 1966, p. 200). They are active approximately 5 to 7 months per year from early spring to fall and hibernate during late fall and winter (Clark 1977, pp. 59-60; Cooke 1993, p. 11). Time spent hibernating is determined by available food resources (Clark 1977, p. 60). In warm weather, even in mid-winter, white-tailed prairie dogs will feed if grasses are growing (Hollister 1916, p. 6; Goodrich and Buskirk 1998, p. 177). If resources are not sufficient, prairie dogs become inactive and spend more time in their burrows (Harlow and

Menkens 1986, p. 795). During periods of high summer temperatures, white-tailed prairie dogs avoid the highest temperatures of midday by foraging in the cooler morning and evening hours (Clark 1977, p. 58).

Distribution and Abundance

The overall species' distribution is mapped as ``gross range.'' The available white-tailed prairie dog literature uses the term ``gross range'' to describe the outer boundary identifying the overall rangewide distribution of the white-tailed prairie dog (Figure 1).

However, not all lands within the species' gross range are occupied or have the potential to be occupied by white-tailed prairie dogs (Seglund et al. 2006, p. 100). The predicted range is a subset of the gross range and thus represents a more accurate spatial representation of the potential range of the white-tailed prairie dog (Seglund et al. 2006, pp. 16, 110; Seglund and Schnurr 2009, p. 23). Predicted range is defined using habitat characteristics of vegetation, land use, slope, and elevation (Seglund et al. 2006, pp. 14-39). Depending on available data, we use gross range, predicted range, or mapped occupied habitat throughout this document to evaluate status and threats to the species.

For example, gross range mapping data was available for our use for all

States across the species' range. However, the data for the predicted range map (Seglund et al. 2006, p. 110; Seglund and Schnurr 2009, p. 23) was only available for the State of Colorado. Information regarding mapped occupied habitat (all areas mapped on Federal lands as occupied by white-tailed prairie dogs since 1985) was available for the State of

Utah, but not for any other States.

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The white-tailed prairie dog occurs from a small area in south- central Montana, throughout much of Wyoming, into western Colorado, and northeastern Utah. There are 20,224,801 ha (49,976,572 ac) within the gross range of the white-tailed prairie dog and 13,066,887 ha

(32,288,981 ac) within the species' predicted range (Seglund et al. 2006, p. 91). Therefore, approximately 65 percent of the gross range has the characteristics necessary to support the white-tailed prairie dog. Wyoming contains the largest amount of white-tailed prairie dog predicted range (75 percent) (Knowles 2002, p. 4). Less than 1 percent of predicted range occurs in Montana (Table 1). The majority of white- tailed prairie dog predicted range (56 percent) occurs on land managed by the Bureau of Land Management (BLM). A significant portion of the predicted range occurs on private land (37 percent). Very little of the predicted range is managed by the Service (0.4 percent), U.S. Forest

Service (USFS) (0.5 percent), or National Park Service (NPS) (0.9 percent) (Table 1).

TABLE 1. Percent Predicted Range by State and Land Management Entity (Seglund et al. 2006, pp. 91, 98, 100, 104, 109).

Total Range

Private

BLM

USFS

NPS

USFWS

State

Other

Colorado

11

37

56