Microclimatic conditions at forest edges have significant impacts on vegetation structure in large Atlantic forest fragments

Abstract

Forest fragmentation creates forest edges, and the effect of those edges increases as the size of forest fragments decreases. Edge effects include changes to microclimatic conditions at the forest edge, which affect vegetation structure. No previous studies have directly tested the relationship between microclimate and vegetation structure (for instance, basal area, trees mean height, dead trees and damage trees) at the edge of forest fragments in the Atlantic Forest domain. We tested the following three hypotheses: (i) the microclimatic conditions differ between the edge and the interior of the forest, (ii) the forest structure differs between the edge and the interior of the forest and (iii) changes to microclimatic conditions at the forest edge negatively affect vegetation structure at the edges. Our results demonstrate that edge habitats are significantly more susceptible to strong winds, lower humidity and higher air temperatures than forest interiors. The microclimate may be considered the principal factor that explains the difference between the vegetation structure of the forest edge and the forest interior. Our results suggest that even large forest fragments in the Brazilian Atlantic Forest may be impacted by negative edge effects.