Influence of environmental variables in araucaria forest lotical environments on a taxonenosis odonata

Abstract

The size of the water bodies can be considered the main controller of the physical and chemical characteristics of the lotic environments. Therefore, the substrate type, river flow, organic and inorganic composition, and habitat heterogeneity are directly related to the size of the lotic environment. In turn, these characteristics are determinant in the distribution and diversity of the immature fauna of Odonata. In this context, we test the hypothesis that different dimensions of lotic environments support similar diversity of Odonata immatures, however, differ in their composition. Thus, we evaluated the influence of water body size on abiotic factors and Odonata immature body taxocenosis. We carried out five seasonal samplings between 2011 and 2012, in the Araucarias National Park, Santa Catarina, in eight environments, through quantitative and qualitative methods. There were 520 Odonata individuals, distributed in eight families and 41 genera. The environments were evidently separated by the classification of the rivers. The highest values ​​of diversity, richness and equitability were recorded in small streams, environments with greater habitat heterogeneity, higher percentage of organic matter and protected by ciliary forest. It was confirmed by this study that the high habitat heterogeneity in low order lotic environments influences the diversity, abundance and richness of the Odonata fauna. Another determining factor for the high indexes was the integrity of the study site, favoring the protection and cycling of nutrients in water bodies.