Natural History Characteristics of Focal Species in the New Mexico Highlands Wildlands Network
Total Page：16
File Type：pdf, Size：1020Kb
Natural History Characteristics of Focal Species in the New Mexico Highlands Wildlands Network May 2003 By David R. Parsons River otter account by Paul Polechla and Kathy Daly For additional information contact: Wildlands Project P.O. Box 455 Richmond, VT 05477 802/434-4077 [email protected] www.wildlandsproject.org ©2003 by the Wildlands Project. CONTENTS Gray Wolf (Canis lupus) . .1 Distribution Habitat Food habits/ hunting behavior Population dynamics Movements Ecology Justification and focal value Management recommendations Mountain Lion (Puma concolor) . .11 Distribution Habitat Food habits/ hunting behavior Population dynamics Movements Ecology Justification and focal value Management recommendations Black Bear (Ursus americanus) . .18 Distribution Habitat Food habits/ foraging behavior Population dynamics Movements Ecology Justification and focal value Management recommendations American Marten (Martes americana) . .25 Distribution Habitat Food habits/ hunting behavior Population dynamics Movements Ecology Justification and focal value Management recommendations Bighorn Sheep (Ovis canadensis ssp.) . .32 Distribution Habitat Food habits/ foraging behavior Population dynamics Movements ii WILDLANDS PROJECT Ecology Justification and focal value Management recommendations Elk (Cervus elaphus nelsoni) . .40 Distribution Habitat Food habits/ foraging behavior Population dynamics Movements Ecology Justification and focal value Management recommendations Beaver (Castor canadensis) . .48 Distribution Habitat Food habits/ foraging behavior Population dynamics Movements Ecology Justification and focal value Management recommendations River Otter (Lontra canadensis) . .52 History and current status Ecology and habitat Population structure and viability Movements Threats and sensitivities Justification and focal value Management recommendations Lynx (Lynx canadensis) . .55 Distribution Habitat Food habits/ foraging behavior Population dynamics Movements Ecology Justification and focal value Management recommendations Literature Cited . .62 iii Gray Wolf (Canis lupus) township (36 mi2 or 93 km2). U.S. Biological Survey trapper, J. Stokely Ligon, estimated the New Mexico state-wide popu- *Please see accompanying Excel chart of Gray Wolf Habitat lation of gray wolves at 103 adults in 1917, 45 in 1918, and Characteristics in the folder titled “Focal Species Habitat practically eliminated in 1927 (Bailey 1931). Bednarz (1988) Characteristics Charts” on the compact disk. proposed 1942 as the estimated year of functional extirpation of gray wolves from New Mexico. Dispersing wolves from INTRODUCTION Mexico continued to enter New Mexico and Arizona for anoth- er three decades. The last wild wolf in New Mexico was dis- Historically, the gray wolf (Canis lupus) was widely distributed covered (dead) in the Peloncillo Mountains (south of the NM throughout the NM Highlands planning area. It was primari- Highlands planning area) in 1970 (Brown 1983). ly associated with mountainous areas and occupied habitats ranging from foothill grasslands to subalpine meadows. The Current. The U. S. Fish and Wildlife Service is currently gray wolf is a top predator and preys primarily on large ungu- restoring gray wolves to the Gila National Forest in the south- lates, especially deer (Odocoileus spp.) and elk (Cervus elaphus). It ern portion of the NM Highlands planning area. As of April requires large core areas for population persistence and safe 2002, two Mexican gray wolves (C. l. baileyi) were known to be linkages between patches of suitable habitat. Gray wolves are free-ranging in the Gila National Forest. About 14 more fully protected as endangered, threatened, or reintroduced Mexican gray wolves were known to be free-ranging in the “experimental” populations by the Endangered Species Act adjacent Apache National Forest in Arizona; and an additional throughout the conterminous United States. Ecologically, the 16 released or wild-born wolves have unknown statuses gray wolf is a top carnivore that serves to maintain ecosystem (Colleen Buchanan, USFWS, personal communication). stability and promote overall biological diversity on a landscape scale. Potential. Areas of approximately 1000 km2 (386 mi2) or greater within foothill or mountainous terrain with the follow- ing characteristics generally represent potentially occupied DISTRIBUTION range for gray wolves: 1) persistent populations of deer and/or elk; 2) low densities of humans and roads; and 3) either con- Historic. Originally the gray wolf was widespread throughout nected by linkages of suitable habitat to, or not more than 80 North America, occurring from near Mexico City to arctic km (50 mi) from, areas of suitable gray wolf habitat of at least regions and from the Atlantic to Pacific oceans (Young 1944). 10,000 km2 (3860 mi2). Large core areas are necessary to pro- It was absent only from extreme desert regions, such as south- vide a source of dispersing gray wolves to recolonize smaller western Arizona, southern Nevada, and southern California areas which are individually unlikely to sustain viable popula- (Young 1944) and from the southeastern United States, which tions over long periods of time. was home to the red wolf (Canis rufus) (Goldman 1944). “Apparently, [gray] wolves were very common in New Mexico at the beginning of its settlement by the Spaniards and later by HABITAT the Americans” (Young 1944:41). Bailey (1931) documented the historical presence of wolves throughout New Mexico, General. The abundance and availability of hoofed mam- including the eastern plains. Conflicts between gray wolves malian prey species (e.g., deer and elk) dictate the potential for and domestic livestock in the Southwest began with early wolves to inhabit an area (Fuller 1997). Otherwise, the gray Spanish settlements (which extended into southern Colorado) wolf is a habitat-generalist, historically occupying all major in the 1600s. Wolf-livestock conflicts peaked in the late 1800s vegetative community types that supported large ungulates in and early 1900s when large numbers of livestock were stocked the Northern Hemisphere, except tropical rain forests and arid on Southwestern rangelands and forests following the comple- deserts (Goldman 1944; Young 1944; Mech 1970; Fuller tion of railroad lines to the region (Brown 1983). 1997). Wolves are adaptable and are not generally affected by non-intensive human activities within otherwise suitable habi- Bednarz (1988) estimated an historical abundance of about one tat, except as those human activities (e.g., illegal shooting, gray wolf per 62 km2 (24 mi2) of suitable habitat or about 1500 predator control, vehicle collisions, or elimination of prey) wolves occupying New Mexico prior to federal predator control might facilitate the killing or elimination of wolves (Fritts and measures initiated in 1915. Bailey (1931) estimated wolf den- Carbyn 1995; Noss et al. 1996; Fuller 1997). Because of high sity in the Gila National Forest in 1906 at about one wolf per human-caused mortality, wolves generally occur where both 1 road and human densities are low (Fuller et al. 1992). Thurber et al. 1994) and are sensitive to disturbances near However, Mech (1995a) notes that improved public attitudes active den sites (Weaver et al. 1996). In Minnesota, wolves per- toward wolves, which presumably translates to increased sist in areas where human densities are less than 4 persons/km2 human tolerance, has led to wolves occupying areas of higher (0.4 mi2) and road densities were <0.70 km/km2 (1 mi/0.9 mi2) road density in Minnesota. Mech (1995a) postulates that grad- and in areas where human densities are <8 persons/km2 (0.4 ual habituation results in wolves becoming more tolerant of mi2) and road densities were <0.50 km/km2 (1 mi/1.2 mi2) human disturbances. (Fuller et al. 1992). W. Robinson placed the critical threshold for human population density at somewhere between 6 and 12 Preferred. Ninety-two percent of the variation in wolf densi- persons per square mile (2.3-4.6 persons/km2) (Klinghammer ty throughout North America is directly related to variation in 1975:433). ungulate biomass (Fuller 1997). That is, the greater the ungu- late biomass, the higher the density of wolves until, theoreti- Thus, the relative quality of wolf habitat is inversely related to cally, other factors (e.g., territoriality) set an upper limit to wolf density of humans, livestock, pets, and roads and directly relat- numbers (Boyce 1995; Messier 1995). ed to the level of favorable human attitudes toward wolves. Since humans cause significant mortality in many gray wolf Because gray wolves have large territorial requirements, rela- populations, isolation or protection from humans or a high level tively large areas are required to ensure population viability of tolerance by humans increase the quality of gray wolf habi- (Soulé 1980; Fritts and Carbyn 1995; Noss et al. 1996). Mech tat. Except for the possibility of vehicle collisions, roads have (1995b:544) defined candidate areas for wolf recovery as “exten- little effect on potential habitat use by wolves. Wolves show a sive wilderness areas with, or near, minimal areas of livestock slight aversion up to about 1 km (0.6 mi) from well-traveled grazing or human residences.” However, in the West and roads, but readily use lightly-traveled, closed, or unplowed Southwest, where most wilderness areas and public lands are roads as travel ways (Thurber et al. 1994; James and Stuart- grazed by domestic livestock, creative incentives to induce Smith 2000). The