Forest formations of the Itapuã State Park, Rio Grande do Sul: habitat characterization of the Brown Howler Monkey (Alouatta clamitans CABRERA, 1940

Abstract

This study aimed to (i) characterize the different forest formations of the ‘Morro do Campista’, Parque Estadual de Itapuã, Viamão, RS, and to (ii) assess aspects related to the composition and the structures of these forest formations that can be influence the density and habitat use of the brown howler monkey (Alouatta clamitans). The transect point sampling method was used to gather data on habitat characterization. Round plots of 6m ratio (113 m2) were used, summing up 107 sampling units. In each unit, all the specimens with a diameter at breast height (DBH) wider than 10cm were registered. The physiognomy of the vegetation of each sampling unit was classified. The phytosociological parameters and Shannon-Wiener diversity index of each formation were assessed. Four forest formations were characterized: hygrophilous, mesophilous, subxerophilous and psamophilous. 1038 individuals of 70 species distributed in 32 families were sampled; amog these, 45 species are included in the diet of the brown howler (A. clamitans). At each forest formation, the occurrence of species used as a food resource by the brown howler monkey was evaluated. Guapira opposita, one of the items of this monkeys’s diet, was the most important species in all formations. Differences were observed in the structure and floristic composition of the forest formations at the ‘Morro do Campista’.  These differences might influence density variations and habitat use by the brown howler monkey groups present in the area, which may have an important effect on the dispersal and distribution of the plant species in the area.