Search

The Brazilian Atlantic Forest (sensu lato) is constituted by Dense Ombrophilous Forest, Mixed Ombrophilous Forest and Seasonal Semideciduous Forest, in which tree species are distributed in gradients, whichever latitude, longitude, or altitude is considered. We investigated whether herb species living on the floor of these forests would have the same geographic distribution pattern. If tree and herb-layer species have coincident distribution patterns, the same conservation units can conserve both species sets; otherwise, specific conservation actions should be taken. We built a presence/absence matrix of 803 terrestrial native species in 80 surveys across the southern and southeastern Brazilian Atlantic Forest. We performed UPGMA, CA and RDA multivariate analyses in order to investigate the distribution patterns. The high degree of agreement among the analyses led us to assume that the geographic distribution of the herb-layer flora occurs as gradients among three main floristic groups: Tropical Ombrophilous forests (mostly lowland forests), Subtropical Ombrophilous forests (mostly montane and upper-montane forests in lower latitudes and sub-montane and lowland forests in higher latitudes, i.e., where temperature is lower), and Seasonal Semideciduous forests (with a marked dry season). Based on different patterns and processes between herbs and trees, and in order to encompass the highest flora diversity, we highlight the importance of creating more reserves in each one of the three main floristic groups of herb-layer species in the Brazilian Atlantic Forest.

Most of southern Brazil is located in a subtropical region, thus representing a climatic and biogeographic transition, which results in different floristic contingents of both tropical and temperate origin in any particular study area. In order to verify the biogeographic affinities of climbing plants, a floristic survey was carried out in a Semideciduous Seasonal Forest remnant located in mideastern Rio Grande do Sul. The presence of the sampled species was recorded for three gradually more distant areas along four divergent expansion lines starting from the study area: northeast, northwest, midwest, and southwest. The distribution data were compiled from the available local and regional literature. The 82 species found comprised 55 genera and 33 families; most species occurred in a single family (Asteraceae), followed secondarily by Apocynaceae, Passifloraceae, Bignoniaceae and Fabaceae. Many species presented a relatively large geographic range, and most species occurred along the northern tropical expansion line. Multivariate analysis included the study area in a group formed exclusively by rain forests of a northeastern expansion line, indicating a southern continuity of the Brazilian Atlantic Forest, although it was locally represented by a lower number of species.