Journal
ECOLOGY
Volume 84, Issue 9, Pages 2432-2443Publisher
WILEY
DOI: 10.1890/02-0448
Keywords
anthropogenic resources; California; Common Raven; Corvus corax; desert tortoise; Gopherus agassizii; hyperpredation; Mojave Desert; prey decoy; spatial distribution of risk; spillover predation
Categories
Ask authors/readers for more resources
Common Ravens (Corvus corax) in the Mojave Desert of California, USA are subsidized by anthropogenic resources. Large numbers of nonbreeding ravens are attracted to human developments and thus are spatially restricted, whereas breeding ravens are distributed more evenly throughout the area. We investigated whether the spatial distribution of risk of predation by ravens to juveniles of the threatened desert tortoise (Gopherus agassizii) was determined by the spatial distribution of (1) nonbreeding ravens at human developments (leading to spillover predation) or (2) breeding individuals throughout developed and undeveloped areas (leading to hyperpredation). Predation risk, measured using styrofoam models of juvenile desert tortoises, was high near places Attracting large numbers of nonbreeding ravens, near successful nests, and far from successful nests when large numbers of nonbreeding ravens were present. Patterns consistent with both spillover predation and hyperpredation were thug observed, attributed to the nonbreeding and breeding segments of the population, respectively. Furthermore, because locations of successful nests changed almost annually, consistent low-predation refugia for juvenile desert tortoises were nearly nonexistent. Consequently, anthropogenic resources for ravens could indirectly lead to the suppression, decline, or even extinction, of desert tortoise populations.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available