ABSTRACT The ready availability of water resources distinguishes the humid forest of Chapada do Araripe, Ceará State, Brazil, from the semiarid vegetation around it. The regional climate demonstrates a marked seasonality of rainfall that affects the ecological strategies of the species found there. We studied the bryophytes of the humid forest of Chapada do Araripe, analyzing their diversity, geographic distributions, and ecological and reproductive aspects. Bryophytes were collected from different substrates using the random-walk method. We gathered information concerning the geographic distribution, functional groups (life forms, light tolerance guilds, and habits) and reproductive aspects of each taxon. We found 76 bryophyte species, predominantly mosses (45 species). Ten new occurrences were recorded for Ceará State, including a new taxon for northeastern Brazil. Most species are widely distributed in that country. Desiccation tolerant (turf) and intermediate (mat and weft) life forms predominated, as well as generalist species in terms of their light requirements. Sixty eight percent of the species demonstrated substrate preferences. Monoicous (67 %) sexual systems predominated over dioicous. The species displayed functional groups and reproductive aspects tolerant to adverse conditions that maximized the use of available resources and allowed their persistence under the seasonal conditions of the forest.

ABSTRACT Environmental conditions in distinct tropical rainforest phytophysiognomies can act as regional filters in determining the distribution of montane bryoflora likewise, local filters inherent to phorophyte species can have modulating influences. We analyzed the bryophyte communities in three phytophysiognomies of Atlantic Forest, in order to examine the influences of local (phorophyte species) and regional (forest phytophysiognomies) filters on their distributions. The study was undertaken in the Serra do Mar State Park, Ubatuba, SP, Brazil, using 1 ha plots in three forest phytophysiognomies along an elevational gradient. Four phorophyte species were selected, with three to seven replicates each. The line-intercept method was used on each phorophyte for collecting botanical material. Multivariate analyses were used to correlate species distributions with environmental filters. A total of 71 taxa were identified. Mean bryophyte coverage did not vary among the different phytophysiognomies, and although their species compositions were markedly distinct, no cohesive or isolated groups were found. Among the local filters examined, phorophyte DBH was found to be correlated with bryophyte coverage; the pH of the bark of Euterpe edulis and the high rugosity of the trunk of the Cyatheaceae influenced species compositions. Other filters not evaluated here may also be relevant for determining species distributions.