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

Abstract

Edge effects impact species richness and composition as a result of environmental changes caused by fragmentation. This study analyzed edge effects on a community of terrestrial ferns and lycophytes in an Araucaria forest in Brazil at sites subjected to differing edge conditions: (1) a site bordering a road running through the interior of a conservation unit, and (2) a site bordering an agricultural property. Twelve 10 × 10 m plots were selected at the edge and in the interior of each site, and accounted for a total of 48 plots. The edges had lost their characteristic floristic identity, suggesting that many species are sensitive to variations in environmental conditions. The edge effect had a negative impact on species richness as shown by the greater average numbers of fern and lycophyte species in forest interiors at both sites. The results showed that the forest fragments in contact with agricultural areas were subjected to more intense edge effects than the fragments bordering a road within a conservation unit.

Survival and development of reintroduced Cattleya intermedia plants related to abiotic factors and herbivory at the edge and in the interior of a forest fragment in South Brazil

“…), and this may have caused changes in the plant appearance and increased rates of herbivory. It may happen due to the low luminosity, as recorded here, and other abiotic factors, such as wind speed, which contribute to plant desiccation and leaf abscission (Murcia 1995;Silva & Schmitt 2015). Since there were no significant development differences between individuals, the herbivory rates may have been more related to the seasonal variations of developmental parameters, such as the intensity of shoot formation.…”

“…As an increasingly fragmented biome, the remaining patches of Atlantic Forest habitat are small, highly impacted and possess a high degree of heterogeneity in abiotic conditions (Viana & Pinheiro 1998). This habitat fragmentation leads to edge effects, which include many microclimatic changes, like increased light and wind exposure and reduced humidity (Silva & Schmitt 2015). Also, changes in forest structure and composition can especially affect the diversity, abundance and distribution of epiphyte plants (Laurance & Yensen 1991;Bernardi & Budke 2010;Bianchi & Kersten 2014).…”

Impacto do efeito de borda sobre a comunidade de samambaias epifíticas em floresta com araucária

“…Outros estudos realizados no sul do Brasil também indicam que há grande número de espécies concentrado em poucas famílias (SCHNEIDER & SCHMITT, 2011;SILVA & SCHMITT, 2015). Polypodiaceae está entre as famílias mais ricas nos levantamentos epifí-ticos realizados no Brasil por Labiak & Prado (1998), Bernardi & Budke (2010) e Schneider & Schmitt (2011).…”

“…Em um estudo desenvolvido por Silva & Schmitt (2015) com espécies terrícolas, a maior riqueza e cobertura no interior desse sítio também foram observadas, sinalizando que as samambaias podem ser consideradas excelentes bioindicadoras de qualidade ambiental, independente do ambiente preferencial de estabelecimento. Em um trabalho de Bataghin et al (2008) verificou-se que a comunidade epifítica apresentou maior afinidade com os ambientes de interior em floresta com araucária.…”

“…Samambaias podem ser um bom instrumento para testar os efeitos da fragmentação e perda de habitats (PEREIRA et al, 2014;SILVA & SCHMITT, 2015). Apesar disso, estudos específicos considerando efeito de borda com esse grupo são escassos.…”