Long-Term Impact of Forest Fragmentation on Tree Functional Diversity, Trait Composition and Aboveground Biomass.

Abstract

Background: Community composition on fragmented forest remnants has been shown to diverge from their natural successional path, revealing an alternative state which has been known as retrogressive succession. Here we show the long-term monitoring of a small forest fragment concerning community structure, species richness, functional diversity and composition throughout 17 years to offer a means to generalize community performance under the impacts of forest fragmentation. Results: The adult tree community showed shifts on its functional composition: reduction in species’ maximum height and percentage of simple leaves, indicating an investment in resource-acquisitive and disturbance adapted traits. However, we also found a gradual increase in wood density throughout the years for the adult community. For the overall community, functional composition analysis indicated a gradual reduction in the percentage of simple leaves and a significant increase in aboveground biomass. The decrease in Hmax and simple leaves, especially for the adult tree community, are mostly related do microenvironmental conditions caused by edge effects, as desiccation and tree canopy damage.Conclusion: Our results show that natural regeneration is being negatively affected, except for aboveground biomass. Although these findings could have resulted from a transient dynamic, they constitute a warning to future conservation policies around the ecological integrity of small forest fragments.