Movement of Desert Grassland Whiptails, Aspidoscelis uniparens, in a Structured Landscape

Landscape structure can affect movement, which is influenced by foraging, thermoregulation, and predation risk. We evaluated search paths relative to landscape cover for a unisexual lizard (Aspidoscelis uniparens) whose movement is primarily motivated by foraging. In outdoor enclosures, we arranged artificial plants in three distributions (uniform, mildly clumped, heavily clumped cover), testing the hypotheses that search effort and efficiency will vary with landscape configuration, and that movement patterns will reflect changes in foraging to accommodate thermoregulation and predation avoidance. We recorded movement parameters, assessing search paths relative to effort, efficiency, and space use. Effort did not vary with landscape configuration, but efficiency, movement patterns, and space use varied with plant distribution. With mildly clumped cover, lizards entered plants more frequently than in other cover configurations. Lizards in both clumped configurations preferentially used areas with more plants. Plant residence times also varied—short-duration visits occurred most often with mildly clumped cover, but with heavily clumped cover, long-duration visits were most common and median residence times were longest. The likelihood of moving to the nearest plant was highest with uniform cover, and that of revisiting plants was lowest with heavily clumped cover. The distribution of cover influenced movement patterns, space use, and search efficiency, likely arising from variation in predation risk.