Spatial structure of bryophyte communities along an edge-interior gradient in an Atlantic Forest remnant in Northeast Brazil

Abstract

The species richness and diversity of epiphytic and epiphyllous bryophytes were investigated along an edge-interior gradient in a large Atlantic Forest remnant in Northeast Brazil. Bryophyte samples were collected at 60 geographically randomised points, which were distributed among five zones located at different distances in from the forest edge. In each site the altitude was recorded and a hemispherical photograph was taken to determine the degree of canopy opening and light transmittance. There was no statistically significant variation of species-richness and diversity in relation to the forest edge, even at 1084 m from the edge. Instead, among the microenvironment variables studied, only altitude supported the most diverse bryophyte floras, especially epiphyllous and shade-tolerant species that are sensitive to disturbance. Besides this, the degree of canopy cover was also relevant, albeit with less significance. These results show that bryophytes respond better to scattered and unique conditions, within moderate microclimates, in the remnant itself than they do to the edge-interior gradient distances alone.