Mirmecofauna em áreas de preservação permanente e plantios florestais no noroeste do Rio Grande do Sul

The ants comprise a very diverse taxon of insects, present high richness and are ecologically important in the different terrestrial ecosystems. The richness and diversity of ants tend to increase according to the complexity of the environments in terms of vegetation and the stage of biodiversity conservation. This study aimed at inventorying and characterizing ant assemblages that occur in two permanent preservation areas, characterized as fragments of native vegetation surrounded by crops, and two eucalyptus plantations, surrounded by crops and pastures. The study was carried out in the municipality of Frederico Westphalen (27 ° 21 '27 ", 53 ° 23' 40" W), located in the northwestern region of Rio Grande do Sul state. Ten pitfall traps and 20 baits, 10 sardines and 10 glucose ones were used in each area. The richness was defined as the number of species that occurred in each sample and was compared by means of rarefaction analysis based on the number of occurrences. The relationship between the ant species and the different environments was verified through a Principal Component Analysis (PCA). The richness of ants was 71 species, belonging to 19 genera and five subfamilies. Seven  species occurred in four sampled environments. The subfamily Myrmicinae and the genera Pheidole and Camponotus were the richest ones in the study. A significant difference was observed regarding the richness, abundance and composition of ant assemblages among the sampled environments. A total of 76.4% of the variation in the occurrence of ants, according to the environments sampled, was explained by the first two components of the PCA. The results point out differences between ant assemblages from forest fragments and those from eucalyptus plantations. They add information about the biodiversity of the study region.