The Relevance of Burial to Evade Acorn Predation in an Oak Forest Affected by Habitat Loss and Land Use Changes

Abstract

Seed burial was proposed as an effective mechanism to evade seed predation in continuous forests. However, the relevance of burial as a mechanism to evade seed predators may be compromised in fragmented forests intensely affected human activities because: (1) predators are usually concentrated within forests patches and this may elevate consumer pressure on seed banks at these habitats; and (2) fragmentation reduces seed production in remnant trees and this then decreases the availability of resources for seed consumers. Thus, seed predators within forest patches might be forced to consume buried seeds after seeds on the soil surface are depleted. Indeed, they may even explore the surrounding matrix habitat in search of food when seeds within the patches become scarce. This study assesses the relevance of burial as a mechanism to evade seed predators in a fragmented oak forest from central Mexico where human activities have generated four habitat types: the interior of remnant forest patches, their edges, the matrix habitat surrounding the patches, and an abandoned agricultural field in the neighborhoods of the fragmented forests. We experimentally assessed removal rates of acorns exposed on the soil surface and buried acorns in all these habitat types and compared them. Our results indicated that acorn burial may be an effective mechanism to evade predation in habitats strongly affected by human activities (e.g., the matrix surrounding the forest patches or the abandoned agricultural field), while it would have little relevance within forest patches.