Spatial analysis of Euterpe edulis (Arecaceae) in the Atlantic Forest. Does adult density affect the spatial distribution of the seedlings?

Abstract

Spatial analysis of Euterpe edulis (Arecaceae) seedlings in the Atlantic Forest. Does adult density affect their spatial distribution? The activity of frugivores and seed dispersers can affect the spatial distribution of plants. We evaluated whether seed dispersal affected the spatial distribution of palmetto, Euterpe edulis, in the atlantic forest of Ihla do Cardoso, Brazil. Our specific questions were: 1) can adult density affect seedling distributions? and 2) do E. edulis seedlings distribute spatially similar to the seedlings of other woody species in the area? To answer these questions, we selected two (10 m x 10 m) plots and spatially mapped all the individuals occurring in them. We found more seedlings, higher densities and seedling clumping both for palmetto and other species in the plot with more E. edulis adults. Furthermore, both the variance in number of seedlings/0.25 m2 and the distance at which the variance estabilized were higher within the plot with higher adult density. These results suggest that the density of palmetto adults influences not only the quantity but also the spatial distribution of its seedlings and the seedlings of other species at finer spatial scales through the activity of frugivores. However, sapling's abundance suggests that diverse density-dependence mechanisms acting on successive life-stages may modify the initial spatial pattern created by frugivores.