Functional diversity of phyllostomid bats in an urban–rural landscape: A scale-dependent analysis

Abstract

Urbanization is one of the most pervasive processes of landscape transformation, responsible for novel selection agents promoting functional community homogenization. Bats may persist in those environments, but the mechanisms responsible for their adaptability and the spatial scales in which the landscape imposes environmental filtering remain poorly studied in the Neotropics. We tested the hypothesis that landscape composition interacts with the spatial scale to affect the functional diversity of phyllostomids in an urban–rural gradient. Based on functional traits, we calculated indices of functional richness, divergence, evenness, and community-weighted means of morphological traits, and classified species into functional groups. We evaluated the changes in those variables in response to forest, grassland, and urbanized areas at 0.5, 1.25, and 2km scales. The number of functional groups, functional richness, and functional evenness tended to be higher in areas far from cities and with higher forest cover, whereas functional divergence increased in more urbanized areas. Our results show that the mean value of wing loading in the assemblage was negatively associated with landscape transformation at several spatial scales. However, environmental filtering driven by grass cover was particularly robust at the 0.5km scale, affecting big-sized species with long-pointed wings. Retaining natural forest in cattle ranging systems at ~12 km2 appears to favor the functional evenness and number of functional groups of phyllostomids. Recognizing the scale of the effect on phyllostomid functional responses appears to be a fundamental issue for elucidating the spatial extent to which phyllostomid conservation planning in urban–rural landscapes should be addressed. Abstract in Spanish is available with online material.