Drastic erosion in functional attributes of tree assemblages in Atlantic forest fragments of northeastern Brazil

• Published in: Biological conservation Vol. 141; no. 1; pp. 249 - 260
• Main Authors: Santos, Bráulio A., Peres, Carlos A., Oliveira, Marcondes A., Grillo, Alexandre, Alves-Costa, Cecília P., Tabarelli, Marcelo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2008; Kidlington, Oxford: Elsevier Science Ltd; Elsevier
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Conservation, protection and management of environment and wildlife; Edge effects; forest ecology; Forest regeneration; forest stands; forest trees; Forestry; Fundamental and applied biological sciences. Psychology; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Habitat fragmentation; old-growth forests; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; plant communities; secondary forests; species diversity; Species richness; Trees; tropical forests; Brazil; Trees; Habitat fragmentation; Edge effects; Forest regeneration; Species richness; Forests; Fragmentation; Edge effect; Atlantic Façade; Tree; Habitat; Community; Erosion; Environmental protection
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/j.biocon.2007.09.018

The long-term dynamics of plant communities remain poorly understood in isolated tropical forest fragments. Here we test the hypothesis that tropical tree assemblages in both small forest fragments and along forest edges of very large fragments are functionally much more similar to stands of secondary growth (5–65-yr old) than to core primary forest patches. The study was carried out in a severely fragmented landscape of the Brazilian Atlantic forest. Nine functional attributes of tree assemblages were quantified by sampling all trees (DBH ⩾ 10 cm) within 75 plots of 0.1 ha distributed in four forest habitats: small forest fragments (3.4–79.6 ha), forest edges, second-growth patches, and primary forest interior areas within a large forest fragment (3500 ha). These habitats were markedly different in terms of tree species richness, and in the proportion of pioneer, large-seeded, and emergent species. Age of second-growth stands explained between 31.4% and 88.2% of the variation in the functional attributes of tree assemblages in this habitat. As expected, most traits associated with forest edges and small forest fragments fell within the range shown by early (<25-yr old) and intermediate-aged secondary forest stands (25–45-yr old). In contrast to habitat type, tree assemblage attributes were not affected by vegetation type, soil type and the spatial location of plots. An ordination analysis documented a striking floristic drift in edge-affected habitats. Our results suggest that conservation policy guidelines will fail to protect aging, hyper-fragmented landscapes from drastic impoverishment if the remaining forest patches are heavily dominated by edge habitat.