Abstract:

The quality of seed deposition often involves habitat and microenvironment selection by seed-dispersing agents (e.g. birds and small rodents) and deposition patterns (e.g. burial of seeds). However, little is known where seeds and nuts are deposited by these animals after their shedding from parent trees. In this study, seed deposition patterns of oil tea (Camellia oleifera Abel., Theaceae) influenced by seed-caching rodents were studied by tracking individual oil tea seeds (labeled with small coded tin-tags) at two stands (secondary stand and primary stand) in an experimental forest of Dujiangyan City, Sichuan Province, China. We found that over 80% of the tagged seeds were well buried 0 – 60 mm deep in the soil and a small part of them were deposited on the soil surface with some leaf litter covering at both stands. Small rodents significantly preferred to select some specific microenvironments (e.g. shrub edge and under shrubs) to cache and eat seeds at each stand. In these microenvironments, they may experience less predation risk during the foraging process. We also found that the microenvironment distributions of caches changed slightly with cache order: a higher proportion of the cached seeds was deposited under shrubs or at shrub edge at higher order cache sites (i.e. secondary and tertiary caches) than at primary cache sites at both stands. Our results indicate that burial of oil tea seeds by small rodents might be a greater benefit for seed survival, seed germination and seedling establishment. Small rodents dispersed seeds from seed sources or parent trees to different microenvironments, which may be beneficial to seed germination and seedling establishment due to more seeds deposited in a favorable environment.

Key words: seed burial, microenvironment selection, scatter-hoarding, seed dispersal, seedling recruitment, small rodents