Characterization of Sympatric or Adjacent Habitats of 2 Deer Species in West Texas

Abstract

Fourteen vegetative parameters and a Land Surface Ruggedness Index (LSRI) were quantified on 306,000 ha of rangeland in western Texas and eastern New Mexico that differentially supported high and low densities of desert mule deer (Odocoileus hemionus crooki) and white-tailed deer (0. virginianus texanus). Percent woody cover was the only parameter measured that was significantly different (P 75%. Increases in white-tailed deer densities were positively correlated (r = 0.69, P < 0.001) with increases in percent woody cover. Using the measurement of percent woody cover, we correctly classified 83 and 65% of the 17 study areas into high and low density classes, respectively, for white-tailed deer and desert mule deer. It is apparent that desert mule deer populations on rangelands in this region could be enhanced by limiting woody plant canopy cover in their habitats to about 40%. Conversely, white-tailed deer populations would be favored by encouraging brush encroachment above this level. J. WILDL. MANAGE. 50(1):129-134 The Trans-Pecos and Panhandle regions of west Texas accommodate ranges of both desert mule deer and white-tailed deer. Landowners, spo smen, and biologists are concerned about an apparent population decline in desert mule deer and an increase in white-tailed deer in areas traditionally considered desert mule deer range (Harwell and Gore 1981). Although no substantive data are available, it is thought that this situation resulted from brush infestation 'Present address: School of Forestry, Fisheries, and Wildlife, 112 Stephens Hall, University of MissouriColumbia, Columbia, MO 65211. 2 Present address: Caesar Kleberg Wildlife Research Institute, P.O. Box 218, Texas A&I University, Kingsville, TX 78363. This content downloaded from 157.55.39.236 on Tue, 11 Jul 2017 17:51:06 UTC All use subject to http://about.jstor.org/terms 130 DEER IN WEST TEXAS * Wiggers and Beasom J. Wildl. Manage. 50(1):1986 (Humphrey 1958, Johnston 1963, U.S. Dep. Agric. 1964) that has altered habitat conditions to favor white-tailed deer (Harwell and Gore 1981). Krfimer (1972) reported similar patterns of white-tailed deer encroachment in the westcentral United States and southern Canada. He suggested that the increasing densities of woody vegetation along water channels may have influenced a shift in species ratio favoring whitetailed deer. Habitat requirements for either deer species in west Texas are not well defined, especially on sympatric and adjacent ranges. This knowledge is essential before concerns regarding the future status of the desert mule deer can be addressed. Further, the lack of habitat information restricts the formulation of management guidelines for possible habitat improvement for either species. Our objective was to determine if selected habitat attributes differentially influenced population levels of desert mule deer and white-tailed deer. Support for this work was provided by the U.S. For. Serv., Rocky Mt. For. and Range Exp. Stn., and the Dep. Range and Wildl. Manage., Texas Tech Univ. We thank the many private ranchers in west Texas and personnel of the Tex. Parks and Wildl. Dep., the U.S. Soil Conserv. Serv., the U.S. Natl. Park Serv., and the U.S. Bur. Land Manage. (BLM) for their support in this project. STUDY AREAS AND METHODS Study areas were selected that were known to support or previously have supported populations of both deer species. They included all or parts of 30 private ranches, 1 state and 1 federally administered park in west Texas, and the Mescalero Sands area in southeastern New Mexico (Fig. 1). These areas totaled 306,000 ha of habitat where desert mule deer and whitetailed deer populations are sympatric or contiguously allopatric. Overlapping populations of desert mule deer and white-tailed deer in Texas occur in the Panhandle and Trans-Pecos geographic regions (Harwell and Gore 1981, Russ 1981). In the Panhandle Region, including the Mescalero Sands in southeastern New Mexico, deer are associated primarily with the Rolling Plains Physiographic Area. The Rolling Plains occupies a zone between the arid, desert regions to the southwest and the more humid regions to the east. Precipitation averages about 52 cm NEW MEXICO