Larval development of anuran amphibians in a river impacted by urbanization: The effect of environmental factors

Abstract

In this work we studied the effects of environmental variables on the abundance and larval development of anuran amphibians in a river impacted by urbanization in the province of San Luis, Argentina. Larval abundance and richness, water temperature and flow rate were assessed in seven sites with different degrees of urban impact along the Volcán river, during four months. Larvae were identified at the level of species, and their length was measured and their stage estimated based on a sample; larvae from three anuran species were recognized in the river: Rhinella arenarum, Hypsiboas pulchellus and Odontophrynus occidentalis. The abundance and richness of larvae varied between sites with different characteristics and, even though they were not significantly correlated with urban impact, it was possible to identify punctual events of impact on larval abundance. Anuran larvae grew and developed in sites with different degrees of perturbation. Effects of flow rate, water temperature and anthropization on growth and development were detected. This work provides basic relevant information on the development of anurans in lotic systems and on the effects of environmental variables in areas with urban impact. The generated knowledge is useful for integrated analyses of environmental quality and as a tool for basic conservation measures of the native anuran fauna.

Keywords: abundance, larvae, environmental impacts.