Tolerant and avoiders in an urban landscape: anuran species richness and functional groups responses in the Yungas’ forest of NW Argentina

Abstract

Urbanization is one of the most important causes of ecological changes and biodiversity loss worldwide, and forests in Latin America provide valuable scenarios to understand the ecological effects of this human-driven phenomenon due to its high urbanization rate. Our aim was to investigate how urbanization shapes species richness (SR) and composition of anuran communities in NW Argentina, and to determine which suite of life history traits are related to anuran tolerance to urban development. We classified anuran species in Functional Groups (FG) based on a series of ecological traits and recognized them as urban-tolerant or urban-avoiders. We constructed an urbanization composite index (UI) through an exploratory factor analysis based on measures of artificial light intensity, noise pollution, land use types, and mean values of LTS, NDMI, and NDVI. We tested the response of SR, FG and species occurrence to UI with Generalized Linear Models and a variation partitioning analysis. Our results showed the negative influence of urbanization on anuran diversity and suggested that the loss of anuran species is not random, pointing to the presence of environmental filters. Only terrestrial frogs that build aquatic foam nests were not affected by an increase in urbanization, so they may be considered as urban--tolerant. Further, our results highlighted the important role of dispersal capacity in structuring the urban anuran assemblages. As ecologists working in urban habitats, we emphasize the need of a more comprehensive and generalized understanding of ecological and life history traits associated with urban tolerant anurans.