Effects of prescribed and wild fires on pine regeneration: the role of seed dispersal by animals

Abstract

As large-scale wildfires are becoming frequent in semi-arid western forests after decades of fire suppression, detailed knowledge of post-fire regeneration dynamics is critical to inform management and restoration efforts. Experiments in unburned forest showed that several species of granivorous rodents (Tamias amoenus, T. speciosus, Peromyscus maniculatus and Spermophilous lateralis) cached pine seeds in microsites in which seedling emergence and survival was significantly higher than microsites typical of wind dispersal. I examined the effects of fire on several aspects of this interaction. A laboratory study suggested that changes in the forest floor after fire may affect the mechanisms, e.g. olfaction and spatial memory, by which rodents find, cache and retrieve seeds. In ash arenas, chipmunks made greater or equal numbers of caches than in sand, retrieved high proportions of their own caches, but detected significantly fewer caches made by others. This suggests that olfaction is less effective in ash and that ash may represent a secure location for storing seeds to avoid pilferage.