Efeitos da distância espacial e da heterogeneidade ambiental sobre os componentes da diversidade Beta em metacomunidades de borboletas europeias

Abstract

Human activities are among the major causes of the decline in biodiversity as they negatively impact two factors that determine the structuring of metacommunities: connectivity and environmental heterogeneity. However, most studies on these factors use only data on the presence and absence of species or focus on abundance but on small spatial scales. To better understand the processes that influence the regional distribution of species in hundreds of European metacommunities, we used butterfly abundance data obtained with high spatial resolution and covering a large geographic extent. We focus on insects because they represent the greatest diversity of terrestrial animals, generally react quickly to environmental changes, and tend to be more susceptible to decline due to changes in habitat quality. Butterflies, in particular, play an important role as pollinators as well as being quite sensitive to changes in habitat quality. Therefore, to understand the processes that lead to the distribution of these organisms and with the aim of potentially contributing to their conservation, we tested different hypotheses about the role of environmental heterogeneity, spatial connectivity and latitude on beta diversity and its components: nestedness and turnover. In our study, a large part of the explanation in the variation of the indices occurred due to the spatial connectivity gradient, both for the beta diversity and for the turnover component. Furthermore, the effect of environmental heterogeneity, which was also spatially structured, proved to be an important determinant of species replacement. We also find a reduction in turnover and an increase in nestedness with latitude, as hypothesized. On the other hand, beta diversity did not show any relationship with the latitudinal gradient. Our study demonstrates the importance of maintaining landscape connectivity and environmental heterogeneity to ensure that species track optimal environmental conditions, as well as the need to partition beta diversity into its components to better understand emerging patterns of species distribution over large spatial scales.