Use of microhabitats affects butterfly assemblages in a rural landscape

Abstract

Landscapes composed of small rural properties may support highly heterogeneous habitat, because they often support distinct types of land uses adjacent to surrounding forest fragments. Many butterfly species may benefit from this kind of landscape, as very distinct microhabitats can be found in a very restricted spatial scale. To better understand how different microhabitats are related to fragmentation in rural landscapes the present study collected the butterfly fauna in 18 sampling point sites, representing distinct types of forest edges and forest interiors. Although closely located, these sites showed no spatial autocorrelation. Instead, a major distinction in species richness and composition was found among forest interior and edge habitats while no significant difference was found in species composition among distinct edge habitats. Therefore, the high segregation of butterfly assemblages found in a very restricted geographic scale suggests the presence of two different groups of butterflies that respond independently to forest fragmentation, the forest interior assemblages and forest edge assemblages. This distinction of butterfly assemblages related to forest interior and forest edges were already reported, but our results highlights that these differences are found mostly due to species turnover between those habitats. In other words, both microhabitat types present a high number of specialized species compared to a smaller fraction of generalist species that may occurs in both microhabitats. Althoug, in the case of Atlantic Forest the species of special conservation concern are those true specialized in forest interior habitats and not those specialized in forest edges, the present study corroborates the importance of sampling different microhabitats when studying fragmentation processes, both inside and outside of fragments. Although forest edges may present different kinds of habitat types, species present along border tend to be as heterogeneous as species present in different locations inside the forest. This information should be considered in sampling designs of biodiversity essays that focus on a more consistent representation of local diversity.