Functional redundancy in bird community decreases with riparian forest width reduction

1. Riparian ecosystems are suffering anthropogenic threats that reduce biodiversity and undermine ecosystem services. However, there is a great deal of uncertainty about the way species composition of assemblages is related to ecosystem function, especially in a landscape fragmentation context.
2. Here we assess the impact of habitat loss and disturbance on Functional Diversity (FD) components Functional Redundancy (FRed), Functional Evenness (FEve) and Functional Richness (FRic) of riparian forest bird assemblages to evaluate (1) how FD components respond to riparian forest width reduction and vegetation disturbance; (2) the existence of thresholds within these relationships; (3) which of the main birds diet guild (frugivores, insectivores and omnivores) respond to such thresholds. We predict that FD components will be affected negatively and non-linearly by riparian changes. However, guilds could have different responses due to differences of species sensitivity to fragmentation and ...