Dispersal and germination of big and small nuts of Quercus serrata in a subtropical broad-leaved evergreen forest

Abstract

Few studies have concerned with the differences in seed dispersal, germination and seedling establishment between big and small seeds within a tree species. In this study, the dispersal and fates of big and small nuts (labeled with coded tin-tags) of Quercus serrata (a dominant canopy tree species) were monitored at two stands (a primary stand and a secondary stand) in a subtropical broad-leaved evergreen forest in the Dujiangyan Region, Sichuan Province, China. We also examined the differences in germination of big and small nuts of Q. serrata without predation by sowing nuts on the ground surface or in the soil. We found that, the big nuts were better survived with longer cache lifetime, longer dispersal distances and higher proportion of emerged seedlings (2% at primary stand, 0.5% at secondary stand) than small nuts. We also found that, there was a marginally physiological difference in germination (germination proportion and seedling height) between big and small nuts. Burial obviously improves germination of both big and small nuts. It is suggested that small rodents may act as an important selective force to affect seed fates, seed shadows and seedling establishment for big and small nut of Q. serrata.