Predation risk alters prey caching behavior and resultant tree establishment patterns

The drivers of plant dispersal and distribution are poorly understood. For nut-bearing trees, interactions between seeds and caching granivores can have a strong influence on population dynamics as unrecovered caches often recruit new trees. Granivore-seed interactions may be constrained by predators as fear alters caching and foraging behavior. We investigated how predation risk affects caching and foraging behavior in fox squirrels (Sciurus niger) and subsequent recruitment patterns of American turkey oak (Quercus laevis) acorns. We marked and tracked acorns to locate fox squirrel cache and consumption points where we assessed fox squirrel perceived predation risk, measured how caching influenced acorn survival and dispersal, and surveyed juvenile oak distributions. Fox squirrels perceived greater risk at caches than consumption points, suggesting predation risk influences caching decisions and cache distribution. Buried acorns survived at higher rates and only buried acorns germinated, though survival did not vary with dispersal distance. Juvenile oaks and cache locations showed similar hump-shaped patterns of establishment away from nearest potential source trees. We conclude that predation risk indirectly shapes plant establishment by altering granivore behavior.