Edge-Related Loss of Tree Phylogenetic Diversity in the Severely Fragmented Brazilian Atlantic Forest

Abstract

Deforestation and forest fragmentation are known major causes of nonrandom extinction, but there is no information about their impact on the phylogenetic diversity of the remaining species assemblages. Using a large vegetation dataset from an old hyper-fragmented landscape in the Brazilian Atlantic rainforest we assess whether the local extirpation of tree species and functional impoverishment of tree assemblages reduce the phylogenetic diversity of the remaining tree assemblages. We detected a significant loss of tree phylogenetic diversity in forest edges, but not in core areas of small (<80 ha) forest fragments. This was attributed to a reduction of 11% in the average phylogenetic distance between any two randomly chosen individuals from forest edges; an increase of 17% in the average phylogenetic distance to closest non-conspecific relative for each individual in forest edges; and to the potential manifestation of late edge effects in the core areas of small forest remnants. We found no evidence supporting fragmentation-induced phylogenetic clustering or evenness. This could be explained by the low phylogenetic conservatism of key life-history traits corresponding to vulnerable species. Edge effects must be reduced to effectively protect tree phylogenetic diversity in the severely fragmented Brazilian Atlantic forest.

Predicting tropical insect herbivore abundance from host plant traits and phylogeny

“…Disturbance leads to welldocumented changes in the structural and functional diversity of plant communities (Guariguata et al 1997, Chazdon 2003, Poorter et al 2004, Santos et al 2010), and we observed generally similar trends in New Guinea. The impacts of forest conversion on herbivorous insects are less well understood.…”

Habitat fragmentation and the future structure of tree assemblages in a fragmented Atlantic forest landscape

“…This has clear implications to contemporary forest diversity even if only a modest fraction of this ecological group can become hyper-abundant in edge-dominated habitats as advocated here. Pioneer-dominated tree assemblages, including those at Serra Grande, have reduced floristic and functional diversity , reduced size structure , low levels of carbon retention (Paula et al 2011), and reduced diversity of floral attributes (Girão et al 2007;Lopes et al 2009) and phylogenetic traits (Santos et al 2010). Moreover, pioneer-dominated assemblages present an altered pattern of fruit phenology and much lower relative abundance of trees bearing large fruits (Tabarelli et al 2010a), which can reduce habitat quality for many frugivorous vertebrates (sensu lato) that play important roles in forest regeneration as seed dispersers and seed predators.…”

“…Population declines, species extinctions, shifts in community structure, and collapse in forest structure proceed rapidly as soon as forest edges are created. Although species losses are expected to reach a relaxation point over time, the ultimate nature/composition of tree assemblages in human-modified landscapes remains an open question ( ArroyoRodriguez et al 2012;Arroyo-Rodriguez et al 2009;Santos et al 2010;Santos et al 2008).…”

Recurrent patterns of phylogenetic habitat filtering in woody plant communities across phytogeographically distinct grassland-forest ecotones

“…Most studies addressing edge effects have usually evaluated fragmented landscapes with abrupt edges (Santos et al 2010), as well as the recolonization of areas that were formerly occupied by forest vegetation (Letcher 2010). On the other hand, edge effects on natural vegetation mosaics, where edges tend to be less abrupt, still lack a deeper assessment (Duarte et al 2007).…”