Edge effects of linear canopy openings on understorey communities in a lowland Atlantic tropical forest




Does the creation of linear canopy openings in a lowland Atlantic tropical forest cause edge effects on understorey treelets, saplings and shrubs?


União Biological Reserve, Rio de Janeiro state, southeastern Brazil (22°25′30″S, 42°02′30″W).


We sampled shrub, sapling and treelet communities at forest edges adjacent to two linear canopy openings (gas pipeline and power line) and in forest interiors far from any edge. Rarefaction curves were plotted to assess differences in species richness among treatments. Variation partitioning was used to assess main drivers of species composition and abundance. Partial Mantel correlations were calculated to verify edge effects controlling for effect of space on the abundance of Euterpe edulis palm and two ecological groups. For this purpose, species were classified either as disturbance-tolerant or disturbance-sensitive.


Edge effects of linear canopy openings affect understorey species composition, but not species richness. Disturbance-tolerant species were more abundant in edges than in forest interiors, while disturbance-sensitive species did not show differences among treatments. However, the late-successional palm Euterpe edulis, which is abundant in forest interiors, was significantly less common at edges. Response to edge effects was stronger among treelets than shrubs and saplings.


The creation of infrastructure-related linear canopy openings caused edge effects that significantly affected understorey communities in the studied lowland Atlantic forest remnant. Such effects however were clearly distinct from those found at typical edges of tropical forest fragments.