Areas of endemism of Pteridaceae (Polypodiopsida) in Brazil: a first approach

Abstract

Areas of endemism (AoE) comprise regions host to two or more endemic taxa, whose distributional limits are congruent and not random. These areas are important for two reasons: they comprise the smallest geographic units for biogeographic analyses and they are priority targets for conservation actions. Ferns are a monophyletic group that despite having a wide geographic distribution, concentrates great species richness and endemism in some regions (centres). The southern and southeastern regions of Brazil comprise one of these centres for the Neotropics. This study aims to verify the AoE of Pteridaceae in Brazil and examine whether the results obtained here are congruent with areas already delimited for other groups and whether there is spatial correspondence between the AoE and Conservation Units. To this end, a database was created with collection records of the 205 Pteridaceae species occurring in Brazil based on a review of herbaria. We analysed 23 815 records for 205 Pteridaceae species using Endemicity Analysis (NDM-VNDM), selecting the fill and assumed parameters, and 1°, 2° and 3° grid-cells. The consensus of 158 AoE, using different grid sizes, was calculated, and subsequently, generalized AoE were established. The Guiana Shield, southern Brazil, southeastern Brazil, and southeastern Bahia were considered generalized AoE. These areas correspond to those found for animals and angiosperms, and in previous studies with ferns. Furthermore, two areas, Acre and Mato Grosso do Sul, were recovered only on grids with 2° and 3°. It will be essential to conduct more research to confirm the persistence of both AoE (Acre and Mato Grosso do Sul), especially after expanding sampling. Most endemic species distribution points occur outside protected areas, demonstrating an alarming situation regarding the conservation of these taxa. In addition, fern distribution data could (and should) be used in conservation practices, programmes and policies, given that they are good ecological indicators and that the distribution of ferns may not reflect that of angiosperms and animals.