What is the role of topographic heterogeneity and climate on the distribution and conservation of vascular epiphytes in the Brazilian Atlantic Forest?

Mapping diversity patterns is important to clarify its causes and is essential information for conservation policies. We map the distribution of vascular epiphytes from the Southern block of the Brazilian Atlantic Forest (SBAF) to understand the main factors responsible for the richness and species turnover, as well as to generate information for the conservation of this functional group. We gathered a data set of vascular epiphytes, mapping the richness and weighted endemism using cells of 0.5 degrees x 0.5 degrees, and performed two Generalized Dissimilarity Models (GDM) using a filter of 18 and 54 species in cells of 5 km x 5 km to evaluate the species turnover and correlation with the climatic and topographic factors. We found four sites presenting both a high richness and endemism. A gradient of richness and species turnover between the coastal and inland regions was confirmed, as well as between the lowlands and the mountainous regions. The main predictors obtained from GDM were geographic distance, cloud cover, and temperature seasonality. The topographic heterogeneity and the resulting climate changes are responsible to enhance the richness and species turnover of vascular epiphytes in the SBAF. It is important to conserve the coastal areas and the mountainous gradients due to the high richness and strong species turnover, but also the inland areas since their composition is quite distinct from previous environments.

Automated summary

The study identified four sites in the Southern block of the Brazilian Atlantic Forest with high richness and endemism of vascular epiphytes. It also confirmed a gradient of richness and species turnover between coastal and inland regions, as well as between lowlands and mountainous regions. The main predictors of richness and turnover were geographic distance, cloud cover, and temperature seasonality.