Determinants of Habitat Selection by Desert Horned Lizards (Phrynosoma platyrhinos): The Importance of Abiotic Factors Associated with Vegetation Structure

Abstract

Abstract The degree to which microhabitat elements such as shade from shrubs are used by lizards and the relative importance of such factors compared to others (e.g., prey availability) remains poorly understood. We examined habitat associations of Desert Horned Lizards (Phrynosoma platyrhinos) to evaluate the determinants of lizard occurrence using surveys along a shrub-steppe bajada in northwestern Utah. We then examined microhabitat preferences of lizards maintained in an experimental arena to explore further the potentially influential factors explaining habitat choice. Greater shrub cover, open understory, and greater cover by cryptobiotic soil crusts were the best predictors of lizard occurrence. While the role of soil crusts is unclear, these other factors may benefit lizards by providing open space for unhindered locomotion and opportunities for temperature regulation through sun/shade shuttling and burrowing. In contrast ants, a primary food source, did not appear to be a significant determinant ...