Is the Seed Dispersal Related to Spatial Pattern of Individuals in Populations? The Case of Dalbergia cearensis

Abstract

The spatial distribution of plant species reveals how members of a population are horizontally organized in the environment. Individuals at different development stages can be influenced differently by abiotic and biotic factors because they are temporally separated. This may cause changes in spatial patterns in ontogenetic stages. The objectives of this study were to verify the pattern of spatial distribution of saplings and adults in Dalbergia cearensis Ducke and relate it to the pattern of seed dispersal. In two areas of 4.0 ha each, located in a Private Natural Heritage Reserve (RPPN) "Não Me Deixes", there were counted all saplings and adults. This data were applied to the spatial analysis by distance indices, using the software Sadie Shell, version 8.0. The aggregation index (Ia) of adults was significant for both areas and showed aggregated distribution. D. cearensis saplings showed an aggregated distribution in the area I and area II. The dispersion distance was proportional for both areas, and the highest proportion of seeds was 10 -20 m away from the center of the aggregation. Spatial analysis by distance indices showed an aggregated spatial distribution pattern for saplings and adults of D. cearensis.