Environmental integrity as a modeler of the composition of the Odonata community.

Abstract

Human actions often alter natural environments, causing homogenization of micro-habitats and, consequently, the loss or replacement of species. Our research evaluates how the effects of environmental integrity and the physical and chemical characteristics of streams influence the adult Odonata community in a region of the Amazon, in western Pará. The data were obtained in 15 streams of first and second order in the municipality of Santarém, Pará, between October and December 2014 (dry season) and between March and May 2015 (rainy season). A total of 544 specimens were collected, distributed in 23 genera, 35 species. Significant differences were observed in the composition of Odonata based on the integrity of streams, and species are replaced as the habitat integrity gradient is reduced, with species that need more preserved conditions extinct locally, making room for generalist species. However, only Psaironeura tenuissima was an indicator of more preserved sites, while Argia sp.1 and Mnesarete smaragdina were indicative of altered sites. None of the variables had any influence on the richness or abundance of Odonata.