Diversidade Beta da Comunidade de Pteridófitas de Florestas de Terra-Firme da Amazônia Central

Abstract

Conservation planning in Amazon is a big challenge. The heterogeneity of habitats is high even in small scales. The understanding of the relationships of biological communities and environmental and geographic variation is needed for conservation planning. The differences of the composition of pteridophytes (ferns and fern allies) between plots due to some local environmental characteristics and geographic distance between plots were evaluated. Thirty eight plots of 0,0625 ha in 150 km2of undisturbed forest in Central Amazon were sampled. The results show that clay content is the main gradient determining species turnover. Canopy openness is negatively related with richness, probably because many species of pteridophytes are susceptible to small increases of light penetration in the understory. The floristic distance between plots was not related to geographical distance, suggesting that ferns are not dispersal limited at this scale. The heterogeneity of pteridophyte communities maybe misrepresented in small reserves because the Amazon is a complex mosaic of habitats and organisms.