Different bat guilds have distinct functional responses to elevation

Abstract

Understanding biodiversity's responses to environmental variations is a challenging task in ecological research. Under a functional perspective, studies have shown that environmental alterations can affect organisms' traits that are related to their performance, fitness and ecological functions. In the present study, we evaluated how the diversity and functional traits of two distinct bat guilds are affected by an elevational gradient in Atlantic forest, southeastern Brazil. Indices regarded to functional diversity and to dominant functional traits (Rao Quadratic Entropy - RaoQ and Community Weighted Mean - CWM) were calculated for both bat guilds: understory and open-space bat faunas. Generalized Linear Models (GLMs) were applied to verify the relation of each metric with elevation, and the presence of non-linear relationships were tested. Results showed that each guild of the bat community reacted differently to the elevational gradient, with statistically significant results of RaoQ for understory bats and of CWM for both guilds (for aspect ratio) or for only one bat guild (mass for understory bats and wing load for open-space bats). Our results illustrate how an environmental gradient can impose different selective pressures in each bat guild and how the distinct bat groups are affected by elevation. This is the first study considering functional aspects of open-space bats in the Neotropics.