A vifauna em três florestas estacionais deciduais em Minas Gerais - Brasil

Abstract

The objective of this work was: I, find variations in birds' composition and diversity in three areas of Seasonally Dry Tropical Forests (SDTFs) in different special e temporal scales; II, analyze if the distribution pattern’ plant and birds between STDFs are similar; III, evaluate the influence of structural heterogeneity on birds’ richness and abundance between SDTFs. The birds were sampled in 2012 in three areas of SDTFs, Parque Estadual Lagoa do Cajueiro (PELC) and Parque Estadual da Mata Seca (PEMS), both in a northern region of Minas Gerais state, and in Santana do Riacho (SRMG), in the central region of this state. The avifauna data were obtained with point counts methodology. The differences of birds’ richness and abundance between different SDTFs, and between wet and dry season, was verified using generalized linear models (GLMs). To verify differences in birds' composition between three areas and also between two seasons, was used non-metric multidimensional scaling analysis (NMDS) and Tukey test. For a verify if the pattern of plants composition is similar of the birds composition, were used Pianka's overlap index. The positive correlation between structural heterogeneity and species richness was verify using generalized linear mixed models (GLMERs). The result of GLMs showed significant differences between all SDTFs, except in the relationship between PEMS and PELC. About the abundance, all areas showed significant differences. The NMDS pointed differences in the bird communities structure between the SDTFs, in which was observed that a relationships between PELC and PEMS showed more greater similarity in the birds composition than all other. For Tukey test, the result was the same observed in the NMDS. For seasonal variations, the NMDS indicate what birds' composition did not show significant differences only in the SRMG, in which there was not significant change in the structure. The largest similarity in birds composition was observed between PELC and PEMS and also the greater richness and abundance of birds, may be due of historical and biogeography factor. The birds composition between seasons showed significant differences, these may be understood by structural changes occurred in habitat between seasons, what further change in the habitat selection by birds. The plant composition showed the same pattern of similarity observed for the birds composition between the STDFs. The GLMERs didn’t show difference between birds diversity and measures of structural heterogeneity. Some explanations can be suggested: first, the small variation of some structural characteristics between sampled areas; second, in environments with lowest primary productivity, how the SDTFs, a energetic concentration is one factor that more influence the species diversity; third, the structural measures used in this work may not be so important in structuring the bird community. In summary, there was variation in richness, abundance and composition at different scales, in which biogeographical and ecological factors are probably the main responsible for these variations. The structural heterogeneity do not corroborate, because habitat more heterogeneous do not has higher species richness. Thus, this study showed the importance of study in different scales to better understand the diversity and distribution of species in the environment.