Temporal variation in a sand dune slack vegetation, Joaquina Beach, Florianópolis, SC

Abstract

The varíation in florístic structure and percentage cover of species present in 3 pennanent plots (5m X 5m) were registered in a sand dune slack. The plots presented differences in topography and water table regime. From december 1989 to december 1990, an increase in species richness and in percentage cover were observed in plot 3 (not flooded) and plot 1 (partially flooded), as a consequence of the great humidity in summer. A great reduction in species number and a small decrease in cover occured until december 1991 being related to lower rainfall. Plot 2 (completely flooded) was surveyed only in december 1990 and april 1992 due to inundation, and showed greater cover percentage but lower species richness. The variationof each species in relation to dry, wet and flooded periods is presented. Among the species of higher cover, the following showed gratest variations in time: Desmodium barbatum, Indigofera sabulicola, Paepalanthus polyanthus, Panicum racemosum, Paspalum arenarium and Stylosanthes viscosa, in plot 3, Paepalanthus polyanthus, Panicum racemosum, P. sabulorum, Petunia littoralis e Stylosanthes viscosa in plot 1 and Eleocharis geniculata and Andropogon selloanus in plot 2.