Blowin' in the wind: ferns and lycophytes connect biogeographic refuges in the Atlantic Forest

Resumen

Aim

Test the floristic structure of fern and lycophyte in the Northeastern Atlantic Forest based on sub-regions of endemism.

Location

Northeastern Atlantic Forest

Taxon

Ferns and lycophytes.

Methods

Floristic composition and environmental data were extracted from 57 remnants and PCA analyses were carried out to assess environmental structuring, NMDS to test floristic dissimilarity, and generalized dissimilarity modeling (GDM) to examine environmental effects on community distribution. Clusters were formed by K-means, and statistical analyses such as Permanova and Anosim were carried out to test the significance of the results.

Results

A total of 307 species were recorded, 93.2% of which were ferns and 6.8% lycophytes. The floristic composition showed 71.6% of species shared between the sub-regions. PCA showed significant environmental differences between montane inland wet forests and coastal forests, but NMDS did not indicate any separation in floristic composition. However, the clusters identified by K-means were highly significant (R = 0,445), in contrast to the groupings of the sub-regions (R = 0,124). GDM explained 78.8% of the distribution pattern and highlighted variables such as geographic distance, cloud cover, rainfall, silt content and soil pH as determinants of the communities.

Main Conclusions

Despite differences in environmental factors between montane inland wet forests and coastal forests, the floristic composition of ferns and lycophytes does not reflect this separation, suggesting that historical biogeography and long-distance dispersal facilitate high connectivity between these sub-regions.