Geographic distribution patterns of species of Pteridaceae (Polypodiopsida) in Brazil

Abstract

The geographical distribution of a taxon is the result of factors specific to the organisms and the environment in which they live. Similar, repetitive, and non-random occurrence arrangements comprise the distribution patterns. Ferns are a group with a wide range, whose spatial patterns are often associated with spore dispersion and environmental factors. Pteridaceae is the most species-rich fern family in Brazil, present in all phytogeographic Brazilian domains. This study aimed to map the occurrence of all Pteridaceae species in Brazil to verify distribution patterns. The occurrence points of the species were obtained from the review of herbaria, and the patterns were delimited according to the congruence of the limits of species presence, and the range in Brazilian states and the biogeographical provinces. Each taxon’s range was classified as continuous and disjunct; for the first one, some subtypes were also considered: very restricted, restricted, moderately wide, and wide. The presence of 205 species was verified, with natural occurrences for Brazil. Minas Gerais and Rio de Janeiro are the richest states in the number of species, and regarding the provinces, the Atlantic and Paraná Forests are the richest. A total of 123 patterns were defined, 93 (173 species) for continuous, and 30 for disjunct (32 species). Considering the continuous patterns, 18 were classified as very restricted (70 species), 14 as restricted (27 species), 51 as moderately wide (63 species), and 10 as wide (13 species). The Brazilian mountain regions are home to a large number of endemic species (such as Serra do Mar, Serra da Mantiqueira, and the Guiana Shield). Environmental characteristics, such as rock types, humidity, precipitation, and elevation seem to be important for the species’ establishment. Furthermore, the dispersal ability of the spores must be considered, given the range of occurrence of the taxa and the age of the lineages.