Examining desert bighorn habitat using 30-m and 100-m elevation data

Recent advances in detailed topographic data availability and computing pow er have caused researchers to scrutinize their use of scale and resolution in their study designs. We undertook this study to determine whether 100-m resolution elevation data would accurately delineate the quality of desert bighorn sheep (Ovis canadensis nelsoni) habitat for females compared to 30- m resolution elevation data. We examined 3 eastern Mojave Desert mountain r anges to determine which resolution best categorized the habitat of female desert bighorn sheep. For each mountain range, locations of females had a s ignificantly less Land Surface Ruggedness index (LSRI) value and significan tly less average habitat classification value at 100-m than at 30-m resolut ion. Seventy-six percent of habitat classifications for females did not cha nge from one data resolution to the other. In addition, although there was a significant overall difference in habitat-quality ratings between resolut ions, there was very little differentiation in proportion of landscape desi gnated as good or excellent habitat (30 m = 27.5%, 100 m = 26.6%), Although 30-m resolution data may be more desirable because of a finer grain of res olution, 100-m data derived from 3-arc-second data yields similar results, is available for more areas, and provides adequate detail to grossly catego rize habitat of desert bighorn females.