Ferns are an important component in the understorey of tropical forests and their distribution is influenced by several biotic and abiotic factors. At a regional scale, soil characteristics and canopy openness play an important role in fern species composition and richness, as well as in the abundance of individuals. Our objective was to compare the influence of edaphic conditions and vegetation structure on the abundance and distribution of fern communities in Atlantic forest and restinga forest. Our hypotheses were that fern species richness and diversity are higher in Atlantic forest than in restinga due to limiting conditions in this habitat and the composition of fern species in Atlantic forest differs from restinga, especially due to differences in edaphic conditions. A principal coordinates analysis was applied to ordinate sampling units in relation to the environmental variables and a permutational multivariate analysis of variance was used to test that environmental variables did not differ between the two vegetation types. Species richness was compared using rarefaction curves. The influence of abiotic variables in species composition and abundance was verified using canonical correspondence analysis. No differences were observed in species richness, diversity or dominance between vegetation types, although abundance was higher in restinga. Fern communities respond to edaphic conditions and vegetation structure variations between vegetation types, the soil playing a major role. A greater variety of habitats resulting from differences in soil drainage in restinga facilitates the co-existence of species with different ecological tolerance, increasing local diversity and compensating for limiting conditions in restinga.

A checklist of ferns and lycophytes from the Lagoa do Peri Municipal Park (LPMP), an Atlantic Forest remnant in Florianópolis, Santa Catarina, southern Brazil, is presented. Collections were made from October 2015 to April 2016. Herbarium specimens were also analyzed. A total of 81 species of ferns and one lycophyte were found, belonging to 14 families and 42 genera. The most representative families were Polypodiaceae (21 spp.) and Pteridaceae (12 spp.). Among the species, 44% were terrestrial, 31% epiphytes, 29% rupicolous, and 2% hemi-epiphytes. Macrothelypteris torresiana (Gaudich.) Ching, an exotic invasive species, was recorded. The number of species found here is lower than reported for similar areas, likely due to anthropogenic activities around and within the park. The constant urbanization occurring around the LPMP emphasizes the importance of the park for conservation of the Atlantic Forest and for maintaining the diversity of ferns and lycophytes.