Diversidade e sazonalidade de Coleoptera em vegetação de caatinga e floresta ciliar no Semiárido Paraibano.

Abstract

The loss of species diversity because of the fast degradation of ecosystems is a worrying fact and a possible tool for evaluating the environmental structure is monitoring of indicator organisms. The Caatinga region is considered the third most degraded biome in Brazil. For the recognition of the environmental structure as well as to increase the knowledge of species richness, it is necessary to survey systematically the components of the biological communities. The order Coleoptera, one of the most diverse groups of insects with approximately 350 000 species, has an enormous economic and ecological importance, and is yet little studied, especially in the Caatinga. This study aimed to: a) characterize aspects of the structure of assemblages of Coleoptera of northern savanna sampled by Malaise traps; b) compare the structure of these assemblages in two units of Paraiba caatinga landscape: an area with preserved xerophytic caatinga vegetation and the other with remnants of riparian forest; c) evaluate the seasonal variation in abundance and richness of species and families. The study was developed in Tamanduá Farm, in the city of Santa Terezinha (7°01’S, 37°24’ W), Paraíba, Brazil. Sampling was conducted during one year, using malaise traps, being three points marked in each sampling unit, and there always was a trap in each of the two areas studied. A total of 1608 individuals were captured from 22 families and 176 species. Considering all the annual survey there was no difference in families and species richness and the number of individuals registered between the two areas. Regarding seasonality, there is difference between the rainy and dry seasons: the families and species richness and number of individuals were higher in the rainy season. There was no significant difference for the two studied units in the rainy regarding these aspects, but in the dry season it was registered a higher families and species richness and a higher number of individuals in the riparian forest. Comparing the number of families and individuals collected in malaise surveys in Caatinga and areas of forest in Paraná state, Southern Brazil, it was concluded that it is lower in caatinga.