HABITAT ATTRIBUTES AND POPULATION SIZE OF TEXAS KANGAROO RATS ON AN INTENSELY GRAZED PASTURE IN WICHITA COUNTY, TEXAS

摘要

An assessment of burrows was conducted at a 15-ha site in north-central Texas known to contain a population of Texas kangaroo rats (Dipodomys elator). The greatest numbers of burrows were in loose, elevated soils where 30-year-old unburned brush piles had decayed, followed by elevated, open areas. The least occupied habitats were fence rows, woody vegetation such as lotebush (Zizyphus obtusifolia) and honey mesquite (Prosopis glandulosa), and rocks. Texas kangaroo rats favored slightly elevated, well-drained, clay loam soils. Dominant vegetation at the study site was indicative of disturbances such as intense grazing by livestock. Burrows were associated with high percentages of bare ground, and herbaceous and woody vegetation of low height. Vegetation in areas immediately surrounding burrows was significantly different from that along transects leading away from burrows in percentages of bare ground and grasses. Dipodomys elator and four other mammalian species were captured during 640 trap nights. The population size of D. elator was estimated to be 33 (± 6) individuals. Sixty-six burrows were counted and multiple burrow use by the Texas kangaroo rat is hypothesized. Counting of burrows is less expensive and time consuming than trapping, and if suitable conversion factors can be established by additional investigations, burrow counts have potential as a means of estimating size of populations that would provide information useful to conservation of this endemic, state-listed, threatened species.