The climate and soil conditions are important predictors of spatial patterns and alpha diversity of plant populations. The spatial distribution of plant populations provides information about ecological processes that control the communities. In this study we investigated the richness and intra and interspecific spatial patterns of ferns in an Evergreen Seasonal Forest in the Amazonia-Cerrado transition. We described the spatial patterns by the univariate and bivariate O’ring function. We recorded four species of ferns samambaias (Trichomanes pinnatum, Lindsaea pallida, Adiantum incertum e Campyloneurum phyllitidis). All species exhibited the intraspecific spatial pattern aggregated. A positive interspecific pattern was observed between T. pinnatum and A. incertum, and L. pallida and A. incertum, however, we did not observe spatial relations between T. pinnatum and L. pallida. The strong climatic seasonality combined with a topographic homogeneity may be influencing the low species richness. The aggregation of these species is indicative that the dispersion limitation and the habitat structuration are determining their distribution. The species positive spatial associations may be reinforced by the environmental stress during the dry season. The absence of spatial relationships may be an indication that neutrality may partially explain the distribution of ferns in the studied forest.
interspecific spatial associations; intraspecific spatial associations; spatial distribution; species richness