Habitat heterogeneity and diversity of bryophytes in campos rupestres

Abstract

Campos rupestres (rupestrian grasslands) are characterized by the presence of rock outcrops associated with an herbaceous-shrub physiognomy typically growing on quartzitic soils; they occur a wide variety of habitats. Bryophytes respond rapidly and efficiently to variation in microclimate. The present work aimed to study bryophyte species richness, diversity and composition, their life forms, and the substrates they colonize in exposed and shaded habitats in campos rupestres of Chapada Diamantina. Collections were made in 25 x 25 m sampling plots. One hundred and nine species were recorded and included a predominance of mosses (78 spp.) over liverworts (31 spp.). Most species (79 %) were restricted to one of the two types of habitat (exposed versus shaded). While the genera Campylopus, Polytrichum, Schlotheimia, Macromitrium and Syrrhopodon were prevalent in exposed habitats, Sphagnum, Lepidozia, Micropterygium, Bazzania and Odontoschisma prevailed in shaded habitats. The rupicolous community was more prominent than the other communities in both types of habitat. “Weft” was the most frequent life form in shaded areas, while “turf” predominated in exposed sites. The high number of rare, and exclusive, species illustrates the high degree of heterogeneity among bryophyte communities in campos rupestres, and demonstrates the importance of habitat heterogeneity for the high diversity.