Species richness and distribution of bryophytes within different phytophysiognomies in the Chapada Diamantina region of Brazil

Emilia De Brito Valente,Cid José Passos Bastos,Kátia Cavalcanti Pôrto

doi:10.1590/s0102-33062013000200006

Abstract

The Chapada Diamantina ecoregion is within the caatinga (shrublands) biome of Brazil. Environmental factors determine the phytophysiognomies that distinguish the ecoregion from the surrounding areas. This study aimed to investigate the distribution of bryophyte flora in this ecoregion, by phytophysiognomy and elevational zone. Analyzing specimens we collected from five municipalities in the region, together with specimens (previously collected from the region) in herbaria, we identified 400 taxa. The phytophysiognomies that presented the highest species richness and the greatest numbers of exclusive taxa were forests and campos rupestres (dry, rocky grasslands), which respectively accounted for 51% and 40% of the taxa, compared with only 5% and 4%, respectively, for the caatinga and cerrado (savanna). Species richness and the numbers of exclusive taxa were highest in the lower and upper montane zones. There was a predominance of neotropical taxa and a significant number of disjunct species found in Brazil and in the Andes region. We conclude that the Chapada Diamantina region is an important center of bryophyte diversity, harboring not only a great number of species overall but also a considerable number of species exclusive to the region, primarily in forests and campos rupestres at elevations above 800 m.

Highlights

The ecoregion of Chapada Diamantina, in the state of Bahia, Brazil, is one of the centers of plant diversity of the Americas (Giulietti et al 1997)
In Brazil, the elevational zonation of bryophytes has been examined in two separate studies, both conducted in the Atlantic Forest within the state of Rio de Janeiro (Costa & Lima, 2005; Santos & Costa, 2010a)
Considering the physical and climatic conditions, the phytophysiognomies within the Chapada Diamantina ecoregion and the bryophyte response to these conditions, this study aimed to investigate the distribution of the bryophyte flora in the phytophysiognomies and elevational zones in this ecoregion within the caatinga biome of Brazil

Summary

Introduction

The ecoregion of Chapada Diamantina, in the state of Bahia, Brazil, is one of the centers of plant diversity of the Americas (Giulietti et al 1997). In Brazil, the elevational zonation of bryophytes has been examined in two separate studies, both conducted in the Atlantic Forest within the state of Rio de Janeiro (Costa & Lima, 2005; Santos & Costa, 2010a) In both studies, the authors found that there is a variation in bryophyte flora composition along an elevational gradient, and that species richness, the number of exclusive taxa and the number of endemic taxa are highest in montane forests (sensu Veloso et al 1991), followed by upper montane formations, lower montane formations and lowlands (sensu Veloso et al 1991)

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