Termitofauna (Insecta, Isoptera) em remanescentes de floresta estacional semidecidual em São Leopoldo, Rio Grande do Sul, Brasil

Abstract

It has been reported that forest fragmentation modifies the richness and/or the abundance of communities. To test this hypothesis it was evaluated the fauna of termites of six fragments of stationary semideciduous forest and an area in early succession. In each one it was designed a transect (100 m x 2 m), divided into 20 plots (5 m x 2 m). In ten of these plots the collections were conducted under stones, in the nests, trunks and branches, over/under trunk barks and in five soil samples (340 cm3) of the A-horizon by plot with a sampling effort of 60 minutes/plot. The composition, the observed and estimated species richness, the relation between area and observed richness, as well as the occurrence and dominance patterns of each species were analyzed. Eleven species from nine genera and two families (Kalotermitidae and Termitidae) were collected, rising the number of species registered in the state from 14 to 18. The subfamily, Apicotermitinae with the upper species richness (S=6), was found in five of the seven areas, while Nasutitermitinae, with the second highest number of species (Sobs=4), was collected in all areas. The richness varied from two to six species, and was not related to the area size. Five species were considered rare, but the others were intermediate. The areas were grouped in four groups with 60, 57, 50 and 40% of similarity, with the species composition as the highest difference between them, suggesting that fragmentation of the local forest influenced more the composition than the richness of termites.