The landscape of fear: habitat use by a predator (Canis latrans) and its main prey (Lepus californicus and Sylvilagus audubonii)

We evaluated the degree of mutual exclusivity of distributions of coyotes ( Canis latrans Say, 1823) and their main prey (two lagomorph species: the black-tailed jackrabbit, Lepus californicus Gray, 1837, and the desert cottontail rabbit, Sylvilagus audubonii (Baird, 1858)) within the landscape by testing two models. The first assumes that prey seek high resource patches and, subsequently, predators seek prey within these patches, and predicts a high degree of overlap in patch use by both. The second model assumes that predator and prey balance not only food resources but reciprocal levels of predation risk and predation success in making decisions on whether or not to use a patch. This model predicts discordance in patch use between predator and prey. We used a combination of GPS-telemetry and camera-trapping data to assess habitat use patterns of predator and prey. Results from this study support the second model regarding spatial use of the landscape by a predator and its prey. Where the use of the landscape by predators and prey seem to be mediated by environmental constraints, both will adjust their predatory or antipredatory strategies based on these constraints. This results in a partial spatial separation of predator and prey across the landscape, providing patches of relative safety for prey but sufficient areas of overlap for predators to be successful.

Compensatory changes in escape and refuge use following autotomy in the lizard Sceloporus virgatus

Following autotomy of a body part to escape from a predator, prey may alter antipredatory strategies to compensate for the inability to use autotomy and impaired escape ability. Because prey that have been captured may increase their assessment of risk posed by a predator, effects of capture may have been attributed to autotomy. I conducted an experiment using three groups of striped plateau lizards ( Sceloporus virgatus Smith, 1938): control, captured, and autotomized. Captured and autotomized lizards were less active on the day after autotomy than controls. Flight initiation distance and distance fled were greater in both experimental groups than in the control group, but did not differ between experimental groups. Flight initiation distance was greater in autotomized than in captured lizards only in males. No sex difference occurred for distance fled. Autotomized lizards entered refuges more than other groups. Escape strategy changed after autotomy to increased reliance on refuge and, in males, to increased flight initiation distance; behaviours that are appropriate to compensate for impaired escape ability. Decreased activity and increased distance fled might erroneously have been considered effects of autotomy, had effects of capture not been assessed. Predictions of escape theory that flight initiation distance and distance fled increase with predation risk were supported.