Variabilidade espacial e temporal de comunidades de aves no Parque Nacional de Chapada dos Guimarães, MT, Brasil

Abstract

We present information about bird communities in three vegetation types of the Cerrado: savanna woodlands (cerrado strictu sensu), swamps (vereda) and forests (cerradão and gallery forests). Samples were collected in a grid with 14 sampling plots, using both mist-netting and point counts. Diversity is measured using presence-absence data. Beta diversity is quantified as a pairwise dissimilarity measure among habitats, using mean Jaccard dissimilarity index. Variation in species composition is expected to occur as environmental conditions changes in distinct dominant vegetation types, considered as different bird habitats: savanna woodlands, forests and swamps. We found greater species richness in forests than in swamps and savanna woodlands. The more contrasting species composition occurred between forests and savanna woodlands and between savanna woodlands and swamps. Forests and swamps didn´t show difference in species composition. Species like Bucco tamatia, Leptopogon amaurocephalus, Pipra fascicauda, Hemitriccus striaticollis, Momotus momota, Nemosia pileata, Myiopagis viridicata, Monasa nigrifrons, Galbula ruficauda, Pachyramphus viridis, Parula pitiayumi, Xolmis velatus, Picumnus albosquamatus, Polioptila dumicola, and Herpsilochmus longirostris were only found in forests. Species like Lepidocolaptes angustirostris, Formicivora rufa, Myiarchus ferox, Legatus leucophaius, Piranga flava, Neothraupis fasciata, Nystalus chacuru and Nystalus maculatus were only found in savanna woodlands. Temporal variation was between seasons. Our findings suggest a positively relationship between bird richness and habitat complexity on one hand, and a negative relationship between bird richness and environmental stressing conditions on the other hand. The results demonstrated that abrupt environmental changes across the habitat gradient cause species variation and each habitat type must be preserved to maintain the regional species diversity. The Cerrado biome is a biodiversity hotspot, and political management strategies should be implemented in order to generate viable strategies in order to insure the conservation of world’s richest tropical savanna.