Mapping potential habitat and range-wide surveying for the Texas Kangaroo rat

Abstract

The Texas kangaroo rat Dipodomys elator is considered a species of conservation concern by state and federal agencies. There have been a limited number of sightings in only seven counties in northern Texas during the past 30 y. The apparent decline of the species has been attributed to habitat loss due to increasing conversion of natural areas into cropland. The magnitude and exact cause of the decline are difficult to determine because of insufficient data on the distribution of the species and its habitat within its relatively small geographic range. Habitat studies have focused on the microhabitat of burrows rather than a coarser-scale identification of habitat and its distribution within the species’ historic range. Multiple species of Dipodomys have demonstrated strong associations with certain soil and land-cover types. Therefore our goal was to develop a range-wide map of potential habitat on the basis of the association of D. elator with specific soil and land-cover types. We used the map to guide roadside surveys and also updated the map with information on D. elator distribution obtained during the surveys. Over the course of two summers (2016 and 2017) we documented D. elator at 138 separate point locations in five counties. A geographic information system-based analysis of soil and land-cover data revealed that the species is associated with clay-loam and loam soils and mixed-grass/shortgrass prairie. We also found an unexpected association with cropland, although we do not know the exact extent to which D. elator actually uses cropland. The surveys provide an updated assessment of the species distribution and the maps of potential habitat indicate areas where the species may still exist.