Edge effects on fern community in an Atlantic Forest remnant of Rio Formoso, PE, Brazil

Abstract

We have investigated how edge effects influence the fern community of Jaguarão Forest (08º 35' 49" S and 35º 15' 39" W), located in the district of Rio Formoso, Pernambuco, Brazil. A comparative analysis was made of the interior and edge of the fragment of forest, regarding the richness, abundance and diversity of ferns in the two areas. Six plots of 10 × 20 m were chosen, three in each area. A total of 381 ferns were recorded, which were distributed among 25 species, 17 genera and 12 families. The two areas (edge and interior) were found to differ, with distinct relative air humidities and temperatures (p = 0.00254 and p = 0.00019, respectively). The interior showed higher diversity (t = 7.251 and p = 0.018) and richness (t = 6.379 and p = 0.023) than the edge area, but the same abundance (t = 1.728; p = 0.226) as the edge. Regarding the composition of the flora, it was clear that the interior is a habitat completely distinct from the edge with regard to the fern community, given that only one species, Adiantum petiolatum Desv., was common to both environments. It was concluded that the edge effect causes a decrease in richness and abundance of the fern species found in Jaguarão Forest, where the more sensitive species are being replaced by species that are tolerant to the disturbance caused by the creation of an edge.

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.…”

“…In contrast, in a remnant of Atlantic rainforest in northeastern Brazil, other authors observed that temperatures were higher at forest edges (Silva et al 2011). Although some authors (Lovejoy et al 1986;Kapos 1989;Murcia 1995;Laurance 1997) suggest that air temperature is one of the most decisive factors for edge effects to occur, evidence to support this fact was not found in this study.…”

“…There are also few studies describing how other taxonomic groups, including ferns and lycophytes (Paciencia & Prado 2004;Barros et al 2006;Silva et al 2011;Pereira et al 2014) and fruticose lichens (Esseen & Renhorn 1998) or bryophytes (Baldwin & Bradfield 2007), respond to these effects.…”

“…The Atlantic rainforest is Brazil's richest biome in terms of seedless vascular plants, and approximately 40% of the fern and lycophyte species that occur in the Atlantic rainforest are endemic to this biome (Forzza et al 2012). Ferns and lycophytes are considered important indicators of environmental quality, because they are responsive to changes in abiotic factors (Ferrer-Castán & Vetaas 2005;Silva et al 2011) such as humidity (Windisch 1992) and light availability (Sharpe & Mehltreter 2010). Grime (1985) demonstrated that many species of ferns and lycophytes are unable to resist the climatic changes caused by edge effects, because they are sensitive to the greater light intensity and wind velocity.…”

“…Certain species in these groups that inhabit the interiors of forests have very narrow ecological amplitude, being practically excluded by the conditions of some microhabitats, and it has been shown that they are highly sensitive to environmental changes (Senna & Kazmirczak 1997) caused by fragmentation. In Brazil, Paciencia & Prado (2004; and Silva et al (2011; conducted comparative analyzes of edges and interiors of rainforests in northeastern Brazil and found that the species richness of ferns and lycophytes was reduced in edges when compared with sites in the forest interior. The edge effect can result in substitution of more sensitive species by those that are more tolerant to the impacts caused by fragmentation, resulting in impoverishment and decharacterization of the local native flora .…”