Arboreous vegetation of an alluvial riparian forest and their soil relations: Porto Rico island, Parana river, Brazil

摘要

The dynamics of alluvial deposits in floodplains forms islands and sandbanks. Deposits frequently accumulate at the river margins and on islands with consequent side growths. One of these sandbanks which started to form in 1952 annexed an area of 12.4ha to the Porto Rico island (53 deg 15 min W and 22 deg 45 min S). At present a forest fragment of approximately 2.0 ha exists in this place. The structural analysis of arboreous vegetation of this fragment showed a floristic gradient related to the physical and chemical variations of the substratum. High density of pioneer species associated to the absence of recruitment of new individuals of these and other successional categories indicated that the forest was impaired in its succession process. Thisfact could be associated with constant disturbances caused by cattle in the area.