The distribution Pattern of Paepalanthus polyanthus was surveved in relation to topography variation and associated vegetation cover in a sand dune slack. Praia da Joaquina, Florianópolis, State of Santa Catarina, Brazil. Quadrats of 0.5 m² were settled continuously along 4 line transects. The density of P. polyanthus, the percentage cover and the predominant species were determined in each quadrat. P. polyanthus showed a contagious pattern of distribution (Dispersion index of Morisita Id>1, P<0.001) in all transects. The individual were concentrated in intermediary areas of the microrelief. P. polyanthus was not observed at elevated sand dune areas, also characterized by lower percentage cover. At lake shores and flooded sites its density was low or the species absent. The factors limiting the distribution of P. polyanthus are discussed on aspects of its population dynamics. P. polyanthus exhibits high mortality after inundation and in higher sand dune areas lower emergence and seedling survival are observed, mainly in periods of low pluviosity. A negative association with Ischaemum minus is suggested and possibly explained by eventual floods or by interference of the dense cover of this grass species on germination and growth of P. polyanthus.
Paepalanthus polyanthus; Eriocaulaceae; Spatial distribution pattern; sand dune slack