The Response of Avian Feeding Guilds to Tropical Forest Disturbance

Abstract

Anthropogenic habitat disturbance is a major threat to tropical forests and understanding the ecological consequences of this disturbance is crucial for the conservation of biodiversity. There have been many attempts to determine the ecological traits associated with bird species' vulnerability to disturbance, but no attempt has been made to synthesize these studies to show consensus. We analyzed data from 57 published studies (covering 1214 bird species) that investigated the response of tropical bird assemblages to moderate forest disturbance (e.g., selective logging). Our results show that the mean abundance of species from six commonly reported feeding guilds responded differently to disturbance and that species' ecological traits (body size, local population size, and geographic range size) and evolutionary relationships may influence responses in some guilds. Granivore abundance increased significantly and insectivore and frugivore abundance decreased significantly following disturbance. These general conclusions were robust to the effects of ecological traits and phylogeny. Responses of carnivores, nectarivores, and omnivores were less clear, but analyses that accounted for phylogeny indicated that these guilds declined following disturbance. In contrast to the other guilds, the reported responses of carnivores and nectarivores differed among regions (Asia vs. Neotropics) and were influenced by the sampling protocols used in different studies (e.g., time since disturbance), which may explain the difficulty in detecting general responses to disturbance in these guilds. Overall, general patterns governed the responses of species to habitat disturbance, and the differential responses of guilds suggested that disturbance affects trophic organization and thus ecosystem functioning.

Ecological impacts of tropical forest fragmentation: how consistent are patterns in species richness and nestedness?

“…These results are consistent with previous studies of birds on impacts of commercial selective logging [91,92] and fragmentation [53] showing that avian feeding guilds differed in their sensitivity to habitat disturbance, and that granivores were least affected. The sensitivity of avian carnivores and predatory ants to fragmentation may reflect their relatively high trophic status, for example, if their feeding requirements mean they have large minimum-area requirements for persistence.…”

“…The sensitivity of avian nectarivores to habitat fragmentation that we detected may reflect that they are generally small specialist species with restricted ranges, which might be expected to be more adversely affected by fragmentation ( [24,93]; but see [53]). In contrast, avian granivores and some guilds of ants may be able to exploit resources in matrix habitats [91].…”

Functional structure of ant and termite assemblages in old growth forest, logged forest and oil palm plantation in Malaysian Borneo

“…Berry et al 2010;Edwards et al 2011) many taxa are strongly affected by disturbance. For example, a review of bird responses to tropical forest disturbance (Gray et al 2007) found significant declines in richness and abundance of insectivores, omnivores and frugivores, although increases in granivores. Also, a review of tropical forest dung beetle communities showed similar diversity declines with increasing habitat disturbance, along with a reduction in the number of forest species (Nichols et al 2007).…”

Do insectivorous bird communities decline on land-bridge forest islands in Peninsular Malaysia?

“…Post-fragmentation bird communities are often unevenly structured, being dominated by few species. Moreover, the fact that bird species consume a variety of food items means that responses to habitat disturbances differ, depending on feeding guild (Gray et al 2007). Insectivorous and frugivorous birds have been shown to be more strongly affected by forest fragmentation (Sodhi et al 2004b) than other major feeding guilds.…”