Swamp vegetations in Brazilian hotspots: Threats, phytogeographical patterns and influences of climate

Abstract

This study reviews and synthesizes information regarding swamps exposed to permanent waterlogging throughout the two Brazilian biodiversity hotspots: the Cerrado and the Atlantic Forest. Our aims were to answer the following questions related to tree composition in these swamps: i) how do climatic and geographical variation influence the similarity and diversity of the swamps? ii) which are the most common species and how do they differ between the hotspots? iii) what is the floristic similarity between the swamps? and iv) what are the threats to which the forests are exposed? Diversity is related to variations in rainfall and temperature that are influenced both by distance from the Atlantic Ocean and altitude. Although sharing key species, the species composition of the swamps shows greater similarity with their surrounding biome than with each other. Swamps are mainly threatened by logging and fragile conservation policies. At least 11 species occurring in this plant community are endangered, reinforcing the need for stricter conservation measures. We offer an updated list of species occurrence and identify species that are the most characteristic of swamp vegetation.