Araucaria Forest fragments have been used for cattle grazing in the Pelotas River basin. We sampled five fragments using 20 x 20 m plots to evaluate the effects of cattle grazing on the population structure of Araucaria angustifolia, Clethra scabra, Dicksonia sellowiana and Maytenus ilicifolia. Despite the small size of the fragments and the high intensity of cattle grazing and selective logging, the species occurred in abundance and had higher seedling and sapling density than did the trees. The effects of cattle grazing on the population structure of A. angustifolia were influenced by the habitat heterogeneity of each fragment, thus a reliable pattern could not be found. Since the other species occurred abundantly in only one fragment, the results obtained were not conclusive.
Endangered species; fragmentation; situ conservation
