Diversidade de cupins (insecta, isoptera) em brejos de altitude: variação espacial, influência de fatores ambientais e similaridade com domínios morfoclimáticos brasileiros.

Abstract

The taxonomic and trophic structures of termite assemblages were studied in 10 areas of altitudinal forests ( Brejo de Altitude ) in the Caatinga dryland biome and their patterns of species richness and distribution were analyzed. A standardized sampling protocol (30 hours x person) was performed in five 5 x 2 m plots distributed along each of six 65 x 2 m transects; the densities of termite nests were also estimated in each of the 10 forest areas in six 65 m x 20 m plots, and climatic, vegetation, and soil parameters were evaluated. Faunal similarity analyses were made between the 10 altitudinal forest areas and 36 other sites distributed among the major Brazilian morphoclimatic domains. Seventy-one morpho species of termites were identified among 799 specimens encountered. In general, the Apicotermitinae were represented by the largest numbers of species and relative abundance, with the humivorous group being dominant. A total of 13 species constructing conspicuous nests were recorded, with an average of 13.1 to 71.8 active nests/ha. Phosphorus was the best predictor variable of termite richness and abundance in all of the areas, with trunk perimeter being the second best predictor. Grouping analysis of the altitudinal forests formed group I (SOR+RFB+RSN) composed of areas at higher altitudes located in the western region of the Borborema Plateau that showed relatively low richness and abundance, and group II [(SJB+RPF+RMM+PVS)+(PRM+PUB)] composed of areas closest to the coastal Atlantic Forest + areas in Ceará State that showed greater richness and relative abundance; the Triunfo/PE site demonstrated the least faunal similarity with the other areas. These results corroborated the hypothesis that Brejos de Altitude forests do not constitute a distinct biogeographical unit. These Brejos de Altitude forests demonstrate greater faunal similarity with Atlantic Forest and Caatinga areas but less similarity with Amazon and Cerrado sites. These patterns of termite distributions appear to reflect Quaternary period cycles of expansion and retraction of Tropical Rainforests during glacial and interglacial periods as well as current climatic and geomorphological factors.