Forest microspatial heterogeneity and seed and seedling survival of the palm Astrocarym murumuru and the legume Dipteryx micrantha in an Amazonian forest / Renato Cintra, John Terborgh.

We examined naturally occurring variation in microsites to determine correlates of post-dispersal seed survival and the performance of established seedlings of two common Amazonian tree species: the palm Astrocaryum murumuru and the legume Dipteryx micrantha. At small spatial scales, variation in leaf litter, understory vegetation, and incident light had significant effects on Astrocaryum seed survival. Survival of Dipteryx seedlings was inversely related to the number of plants of all species around them. Seedling growth and survival of both plant species were unaffected by variations in the biotic and abiotic components of microsites, such as microrelief, leaf litter thickness, and the presence of an adult palm tree. At larger spatial scales Astrocaryum seedling survival was inversely related to the density of broad-leaved monocots (Heliconi spp.) and positively related to incident light. Mammals were primarily responsible for both seed and seedling mortality. The results of this study indicate that environmental heterogeneity created by leaf litter, understory vegetation and light could be important determinants of offspring survival in these two large-seeded Amazonian tree species.