Floristic and ecology of orchidaceae in semideciduous seasonal forest fragment in Araras, São Paulo, Brazil

The neotropical riparian forests are widely studied, but there are little informations about orchids in phytophisiognomies. The aim of this study was to characterize the floristic composition, and ecological relationship and categories related to habitat of Orchidaceae family representatives in riparian forest in Semideciduous Seasonal Forest fragment in Araras, SP. By the demarcation of 20 plots of 20 X 10 m (400 m2) parallel to the local water body, it was sampled 10 genera and 12 species: Baptistonia cornigera, Campylocentrum grisebachii, Campylocentrum robustum, Capanemia micromera, Catasetum fimbriatum, Cattleya loddigesii, Oeceoclades maculata, Pleurothallis miniato-lineolata, Polystachya estrellensis, Sacoila lanceolata and Lophiaris pumila. The existing populations of orchids in the study area decreased due to anthropogenic disturbance, resulting in the current low diversity. High densities presented by some species, chiefly L. pumila, make it clear the processes of recolonization related to adaptative mechanisms and to the current conservation status of the fragment.