Functional attributes change but functional richness is unchanged after fragmentation of Brazilian Atlantic forests

1. Fragmentation of tropical forests is one of the greatest threats to global biodiversity. Understanding how biological and functional attributes of communities respond to fragmentation and, in turn, whether ecosystem functioning is impacted upon are critical steps for assessing the long-term effects and conservation values of forest fragments. Ecosystem functioning can be inferred through functional diversity metrics, including functional richness, evenness and divergence, which collectively quantify the range, distribution and uniqueness of functional traits within a community.\ud \ud 2. Our study was carried out in forest remnants of the Brazilian Atlantic rain forest, which is a global hotspot of threatened biodiversity that has undergone massive deforestation and fragmentation. We focus on trees, which play critical functional roles in forest structure, food provisioning and carbon storage, to examine community organization and functional diversity across a gradient of fragmentation, from small to large fragments and at edge versus interior habitats.\ud \ud 3. The interiors of small fragments have marginally higher species richness, but similar community structures, to the interiors of bigger fragments. In contrast, fragment edges suffered significant losses of species and changes in community structure, relative to fragment interiors.\ud \ud 4. Despite shifts in community organization, functional richness was not impacted by fragmentation, with the same number of functions provided independent of fragment size or proximity to edge. However, functional evenness and functional divergence both increased with decreasing fragment size, while fragment edges had lower functional evenness than interiors did, indicating that the abundance and dominance of functional traits has changed, with negative implications for functional redundancy and ecosystem resilience. At fragment edges, large-fruited trees, critical as resources for fauna, were replaced by early successional, small-seeded species. The influence of fragment size was smaller, with a reduction in very large-fruited trees in small fragments counterbalanced by increased numbers of fleshy- and medium-fruited trees. Wood density was not impacted by fragmentation.\ud \ud 5. Synthesis: these results suggest that the interiors of even small fragments can contain important biodiversity, ecosystem functions and carbon stores, offering potential opportunities for cobenefits under existing carbon markets. Retaining forest fragments is an important conservation strategy within the highly threatened Brazilian Atlantic forest biome

Variações estruturais e características edáficas em diferentes estádios sucessionais de floresta ciliar de Tabuleiro, ES

Este estudo teve como objetivo analisar a comunidade arbórea em três estádios sucessionais florestais ciliares na Área de Proteção Ambiental Lagoa de Jacunem, no Município da Serra, ES. Para a caracterização estrutural foram empregadas 60 parcelas de 10 m², totalizando 0,6 ha amostrado. As parcelas foram distribuídas equitativamente entre cada estádio sucessional, onde foram incluídos os indivíduos com CAP > 15 cm, a 1,30 m do solo. Em cada estádio também foram coletadas amostras compostas de solo para posterior análise química. As áreas apresentaram solos distróficos, sendo por isso pobre em nutrientes e com acidez elevada. Foi amostrado um total de 851 indivíduos, distribuídos em 79 espécies. A diversidade (H') de espécies foi aumentando gradativamente seus valores, sendo 2,70 no estádio inicial, 2,88 no estádio médio e 2,96 no estádio avançado, respectivamente. A equabilidade J' foi de 0,77 nos estádios inicial e médio e 0,73 no estádio avançado. A densidade decresce significativamente (ANOVA; F=6,55; P<0,01) em direção aos serais mais avançados. Os valores de área basal total variaram significativamente entre os estádios sucessionais (ANOVA; F = 24,87; P<0,0000001). Esses resultados evidenciaram características estruturais e diversidades diferenciadas de acordo com o estádio de sucessão em que cada fragmento se encontrava

Indirect effects of habitat loss via habitat fragmentation: A cross-taxa analysis of forest-dependent species

Recent studies suggest that habitat amount is the main determinant of species richness, whereas habitat fragmentation has weak and mostly positive effects. Here, we challenge these ideas using a multi-taxa database including 2230 estimates of forest-dependent species richness from 1097 sampling sites across the Brazilian Atlantic Forest biodiversity hotspot. We used a structural equation modeling approach, accounting not only for direct effects of habitat loss, but also for its indirect effects (via habitat fragmentation), on the richness of forest-dependent species. We reveal that in addition to the effects of habitat loss, habitat fragmentation has negative impacts on animal species richness at intermediate (30–60%) levels of habitat amount, and on richness of plants at high (>60%) levels of habitat amount, both of which are mediated by edge effects. Based on these results, we argue that dismissing habitat fragmentation as a powerful force driving species extinction in tropical forest landscapes is premature and unsafe