Are the pattern of abundance and distribution of anuran related with the structure of plant communities in aquatic habitats of San Luis city (Argentina)?

Abstract

The presence and permanence of anurans in urban ecosystems relies on the availability of aquatic habitats for reproduction, where vegetation is an important feature determining habitat selection. The aim of this study was to estimate species composition and relative abundance of anurans, based on vocalizations, and to explore relationships between these variables and composition and structure of vegetal communities and environmental variables (temperature, humidity and photoperiod) in urban aquatic habitats in San Luis city. Urban aquatic habitats were occupied by three anuran amphibian species, Leptodactylus mystacinus, Rhinella arenarum y Odontophrynus americanus, during their reproductive period. L. mystacinus and R. arenarum showed a similar and significantly higher than O. americanus relative abundance. The number of larvae fluctuated not significantly during the reproductive period and was not signifi cantly affected by environmental variables. Total relative abundance was significantly affected by photoperiod, but only the relative abundanceof R. arenarum varied temporally, being significantly higher on November than in February and March. Relative abundance of anurans (all species) was different between sites; this could be influenced by the perturbation degree and the structure and composition of plant communities, which are, at the same time, determined by environmental variables. Anurans were favored in urban areas away from the city center, where the exotic plants cover was low and the herb stratum was high and complex.

Key words: amphibians, vegetation, species richness, urban ecosystems.