Pollen and seed flow patterns of Carapa guianensis Aublet. (Meliaceae) in two types of Amazonian forest.

摘要

Various factors affect spatial genetic structure in plant populations, including adult density and primary and second-ary seed dispersal mechanisms. We evaluated pollen and seed dispersal distances and spatial genetic structure of Carapa guianensisAublet. (Meliaceae) in occasionally inundated andterra firmeforest environments that differed in tree densities and secondary seed dispersal agents. We used parentage analysis to obtain contemporary gene flow estimates and assessed the spatial genetic structure of adults and juveniles. Despite the higher density of adults (di-ameter at breast height25 cm) and spatial aggregation in occasionally inundated forest, the average pollen dis-persal distance was similar in both types of forest (195106minterra firme and 17587 m in occasionally inundated plots). Higher seed flow rates (36.7% of juveniles were from outside the plot) and distances (155 84 m) were found interra firme compared to the occasionally inundated plot (25.4% and 11469 m). There was a weak spatial genetic structure in juveniles and interra firme adults. These results indicate that inundation may not have had a significant role in seed dispersal in the occasionally inundated plot, probably because of the higher levels of seedling mortality.