Anuran assemblage in a rice field agroecosystem in the Pantanal of central Brazil

Abstract

Agricultural practice is an important factor that threatens biodiversity. However, modified habitats such as irrigated rice fields could serve as potential refuges for several species of amphibians. This study describes the composition of an anuran assemblage in an irrigated rice field system in the Pantanal floodplains of central Brazil. The low species richness found in rice fields and neighbouring habitats can be interpreted as resulting from the structural limitations of a modified environment. Flooding occurs for longer periods than in natural areas and leads to a lack of dry space, hindering the presence of terrestrial anuran species. Furthermore, the absence of herbaceous vegetation and shrubs in cultivated fields prevents the establishment of species of large tree frog. A positive correlation was found between rainfall and richness, although the abundance of some species did not fit this relationship. The present study suggests that only anuran species that are generalists and highly resilient will survive as the natural wetlands are transformed into irrigated rice plantations.

Keywords:

• amphibians
• wetlands
• rice fields

Acknowledgements

The authors are grateful to Universidade Federal de Mato Grosso do Sul and Conselho Nacional de Desenvolvimento Científico e Tecnológico (Process no. 470148/2006-3) for financial support on the research, to Fazenda San Francisco for logistic support and to Ibama for permission to capture anurans (Process no. 13788-1). Thanks are extended to F.I. Martins and C. Aoki who helped with fieldwork, B. Allain who kindly improved early drafts of the manuscript and C.P.A. Prado, R.A. Brandão, C. Strüssmann, V.L. Ferreira and A.P. Lima who made valuable suggestions on the manuscript. F.L. Souza receives a research grant from Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq (306034/2008-5).