The Heterogeneity of Amazonian Treefall Gaps and Bird Community Composition
Year: 2008
Type: article
Abstract: It is widely recognized that the physical disturbances created by treefall gaps influence animal communities in tropical forests. However, how the bird community is affected by the internal heterogeneity of gaps is still unstudied. Twenty- five treefall gaps were sampled for their understory and canopy bird assemblages in a mature Central Amazonian rain forest. Mist nets, binoculars, and tape recorders were used to sample the bird community. Environmental variables were chosen for their known influence on forest regeneration through variation in sunlight exposure (gap size, canopy openness, aspect, gap orientation, and elevation), and for representing gap dynamics (gap age and vegetation structure). The bird community attributes analyzed were species abundance, richness, and community composition. Species richness and relative abundance did not vary significantly according to gap characteristics. The gap variables that most influenced bird community composition were related to sunlight exposure, and frugivores and nectarivores were the most affected guilds. Insectivores were affected only by gap size while understory species were not affected at all. The results indicate that differences among treefall gaps in the Manaus region may have a stronger influence just on some species, as shown by changes in community composition only than on overall species abundance and richness. Among all groups, frugivorous and nectarivorous birds were shown to be the most affected guilds by gap environmental variables. As previously suggested, we bring more evidence showing that treefall gaps may indeed function as keystone places for birds for their role in sustaining frugivores and nectarivores in periods of fruit scarcity in the forest. Accepted 15 January 2008.
Authors: Cristina Banks‐Leite, Renato J. Cintra
Language: English
Topic: Avian ecology and behavior
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W2182644262