A comparison of bird communities in the anthropogenic and natural-tree fall gaps of a reduced-impact logged subtropical forest in Bolivia

We studied bird community composition and abundance within four vegetation and disturbance categories located within selectively logged and unlogged forest in a Bolivian subtropical lowland forestry concession. The logged forest was subject to reduced-impact logging between 1 and 4 years prior to our study. The four categories were: 1) 'gap' points possessing natural or anthropogenic tree-fall gaps,' 2) 'target' points with one of five commercial tree species of harvestable size; 3) 'future' points possessing a commercial tree below harvestable size; and 4) 'non-target' points not possessing harvestable tree species. The bird community composition of logging gaps significantly differed from that found within natural tree-fall gaps in the unlogged forest (P < 0.05). Species richness was higher in natural tree-fall gaps than in anthropogenic gaps. Furthermore, a higher proportion of disturbance sensitive species were associated with natural-tree fall gaps, whereas a higher proportion of disturbance tolerant species were associated with anthropogenic gaps. No significant difference was detected in the bird community composition for the other three vegetation categories surveyed. We discuss the conservation and silvicultural repercussions of these results.