Case Study: Using Soil Survey to Help Predict Sonoran Desert Tortoise Population Distribution and Densities

Micro-geographic variation in burrow use of Agassiz’s desert tortoises in the Sonoran Desert of California

“…Tortoises typically occupy multiple burrows in a given year, in different substrates, and burrows are usually characterised by their half-dome-shaped entrance and large mound of excavated material at the opening (Burge, 1978;Luckenbach, 1982). Tortoises are believed to select burrows based on a variety of factors that affect their suitability for survival including slope, aspect, and proper soil type for digging and stability (Anderson et al, 2000;Bulova, 2002;Ernst & Lovich, 2009;Lovich & Daniels, 2000;Stager et al, 2017). Proper placement and construction of a burrow has important fitness consequences for a tortoise because they provide protection from predators, thermal extremes, floods, fires, and other mortality factors (Kinlaw, 1999;Lovich & Daniels, 2000).…”