Efeitos da fragmentação sobre espécies arbóreas em remanescentes de floresta estacional semidecidual.

Abstract

The fragmentation of habitats and the resulting biodiversity loss process today is the main problem to be faced by environmentalists. Several changes are resulting from this process in plant communities as changes in species composition, structural and functional modifications. The study objectives were to evaluate the influence of fragmentation on the composition, richness, diversity, evenness and functional characteristics between forest patches of different sizes, and check for nesting patterns between communities and the influence of environmental and spatial variables on these patterns. Twelve areas were sampled in 12 forest fragments in FES Caiuá Ecological Station and its surrounding area in the city of North Diamond - PR, one sample area per patch. For the inventory of vegetation was used the point center quarter method for two quadrants of sampling strata, stratum 1 for individuals with Circumference at Breast Height (CBH) > 15 cm 2 for individuals and stratum greater than 1 m in height and with CBG <15 cm. The tree community appeared highly influenced by the fragmentation process, with significant differences found between the size of the fragments to species richness, diversity, evenness and functional groups. Selective extinction processes generating nested communities were detected between communities is influenced mainly for shape and altitude of the fragments. Overall, the study indicates differences in the composition and structure of tree communities in fragments between different areas and shapes. Larger fragments were more conducive to maintaining a tree community with greater richness, diversity and evenness, however, the preservation of smaller areas becomes important in maintaining the richness of micro-habitats and connectivity processes. The onset of nesting patterns indicated response processes of extinction on the community resulting from the fragmentation demonstrating the importance of these standards in planning and implementing conservation actions in fragmented landscapes.