Richness preservation in a fragmented landscape: a study of epiphytic bryophytes in an Atlantic forest remnant in Northeast Brazil

Abstract

Fragmentation and loss of habitat are considered to be the main causes for the decrease in biological diversity in tropical forests. This study aims to evaluate the size and edge effects on tree physiognomy and on the bryophyte community structure in relation to richness, composition, and distribution of ecological groups. Ten forest fragments from the Murici Ecological Station, in the state of Alagoas (Brazil) were studied. In each fragment 10 evenly spaced plots were delimited along four 100 m transects located perpendicularly to the border. One hundred and six species were found, of which 56 were liverworts and 50 were mosses. Results showed that flora impoverishment and other variations in the bryophyte community structure are related to fragment size. Shade epiphytes were the most affected. An ‘edge effect’ was not detected in this study. Vegetation physiognomy parameters contributed partially to the bryophytes’ responses. Diameter at breast height, height, and the density of trees were both positively correlated with bryophyte richness, while canopy openness was not. Our results suggest that the larger fragments are better structured physiognomically, i.e. the trees are taller and have larger diameters, which are probably important factors in enabling them to retain a rich bryophyte flora.

Keywords:

• Bryophytes
• Edge effect
• Forest physiognomy
• Shade epiphytes

The authors thank the following: Dr Olga Yano (Instituto de Botânica de São Paulo), Dr Steven Churchill (Missouri Botanical Garden), Dr Anna Luiza Ilkiu-Borges (Museu Paraense Emílio Goeldi), Dra Denise Pinheiro da Costa and Dra Thaiz Vaz (Jardim Botânico do Rio de Janeiro) for help in identifying bryophyte species and Dr Jeff Bates for all the suggestions and improvements in the text. The authors also thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Fundação O Boticário de Proteção à Natureza for the financial support.

Taxonomic Additions and Changes: Nil.