Impact of edge effects on avian foraging guilds in Mahamavo Forest, Madagascar

Abstract

Tropical forests around the world are becoming increasingly fragmented as a result of anthropogenic influences, resulting in forests becoming more and more vulnerable to edge effects. Edge effects have been noted to have not only an impact on ecological structures of habitats, but also on species diversity and abundance. However, edge effects on avifauna is unclear, especially in the understudied Mahamavo Forest. General patterns of abundance and species richness were initially analyzed, with further investigation on the impact of edge effects on bird foraging guilds. NMDS plots and ANOVA tests revealed that there was no significant difference in species between forest core and edge habitats. Based on Kendall rank correlations between foraging guilds and distance from edge, insectivore, granivore, carnivore, and frugivore species abundance significantly decreases as distance from edge increases. Nectarivores and omnivores were not significantly correlated to distance from edge. Future studies should investigate how foraging guilds may be affected by species in surrounding matrix landscapes and how roadside effects may change the standard definition of forest edge effect.