LEAF-LITTER EFFECTS ON SEED AND SEEDLING PREDATION OF THE PALM ASTROCARYUM-MURUMURU AND THE LEGUME TREE DIPTERYX-MICRANTHA IN AMAZONIAN FOREST

The amount of leaf litter fall produced by different: tree species in tropical forests varies in space and time. Falling litter may cover se eds and thereby enhance their survival by making their detection by se ed predators more difficult. Tests were made to determine whether Astr ocaryum murumuru and Dipteryx micrantha seeds survive better in micros ites covered by leaf litter. Seed numbers and litter cover on the fore st floor were experimentally manipulated. How natural variation in lea f litter cover and thickness affects seed and seedling survival of the se two plant species was also examined. Seed survivorship was signific antly higher for both plant species in microsites with leaf litter tha n in those with bare soil. Results from an experiment in which the lit ter was not disturbed showed that Astrocaryum seed survival was positi vely correlated with litter thickness (defined as the number of overly ing dead leaves). Astrocaryum seedling survival was also significantly affected by leaf litter; more seedlings survived in shallow litter. L eaf litter had no effect on Dipteryx seedling survival. The results of the study suggest that early recruitment of both Astrocaryum and Dipt eryx is influenced by the spatial distribution and amount of forest le af litter.