Fragmentation and loss of habitat: consequences for the fern communities in Atlantic forest remnants in Alagoas, north-eastern Brazil

Abstract

Background: The reduction of forest areas and the fragmentation of remaining forest is a major threat to biodiversity and is one of the primary causes of species extinction in the Atlantic forest biome. Aims: To evaluate the effects of the fragmentation and loss of habitat (size, edge effect, isolation and type of matrix) the richness, abundance, diversity and species composition of ferns in Atlantic forest fragments. Methods: For each of 11 fragments, plots of 10 × 20 m 2 were compared in the interior and at the forest edge. Data were analysed by general linear models, or by the use of similarity indices for floristic composition. Results: Eighty-eight species were recorded. Fragment size and type of environment (interior vs. edge) were related to the biological variables studied: large fragments and forest interior environments had larger populations of ferns, with a higher diversity. Floristic compositions were distinct for both the interior vs. edge environments and large vs. small fragments. Conclusions: Although larger fragments present a higher number of species, the preservation of smaller fragments, which have a different suite of species from those found in the large fragments, is important to guarantee the maintenance of the highest number of fern species in the Atlantic forest. Small fragments are not merely subsets of the species occurring in the larger fragments. The turnover in the species composition between fragments of different size suggests high spatial variability in the study area.

The effects of fragmentation on Araucaria forest: analysis of the fern and lycophyte communities at sites subject to different edge conditions

“…Nevertheless, it was observed that the edge effect was stronger in Cravina, where the species richness reduced to half, compared with Macaco Branco, suggesting that an agricultural matrix enhances the edge effect. The current study therefore provides further evidence supporting the findings of Paciencia & Prado (2004), Silva et al (2011), andSilva et al (2014), indicating that ferns and lycophytes are potentially vulnerable to edge effects.…”

Trees represent community composition of other plant life-forms, but not their diversity, abundance or responses to fragmentation

“…However, most fragmentation studies of plants have concentrated on trees, which might be expected to respond slowly to environmental changes relative to other life-forms because of their long life spans and generation times, and larger size 25 – 27 . By comparison, rapid responses to fragmentation have been observed in herbs 28 , 29 , lianas 30 , 31 , and ferns 32 , 33 , suggesting that trees may not represent their dynamics well. Studies of multiple plant life-forms provide a more robust understanding of fragmentation impacts on plant communities 34 , 35 , but they are rare.…”

Diversity and composition of ferns and lycophytes in a fragmented landscape in Ecuadorian Amazonia

“…Moreover, forest-patch configurations, such as patch size, isolation, and the distance to edge, have also been related to changes in fern diversity (Murakami et al 2005;Silva et al 2015). Fern richness tends to be lower near forest edges (Silva et al 2014), with some groups, such as the epiphytes, being more vulnerable to the environmental conditions near edges than terrestrial species (Zuleta et al 2016). Due to ferns' sensibility to modifications in their habitat, it has been claimed that they can be used as an indicator group for environmental degradation caused by increasing edge effects in the landscape (Paciencia & Prado 2005b;Silva et al 2015Silva et al , 2018.…”