Climatic dependence in the daily and seasonal calling activity of anurans from coastal wetlands of southernmost Brazil

ABSTRACT

Calling activity is an important indicator of the daily and seasonal patterns of anurans activity and can be regulated by a variety of biotic and environmental factors. We studied the influence of environmental factors on the daily and seasonal calling activity of an assembly of anurans in subtemperate coastal wetlands from southernmost Brazil. We recorded the local environmental variables and species calling activity from December 2012 to April 2014. We recorded 10 active frog species with the aid of an automated audio recording system that enhances the data acquisition in the field. The calling activity was mainly influenced by water temperature and rainfall which is a different pattern from that of subtropical areas, where the air temperature is the main environmental factor regulating frog activity. Species of closely related taxonomic groups had reproductive modes dependent on certain environmental variables. Leptodactylidae species were more often active in the warmer seasons whilst Hylidae species were less dependent on temperature. Most species were nocturnally active and had a calling activity negatively related to temperature, a pattern that reinforces the role of the sunset as a main environmental predictor of the onset of the calling activity in nocturnal species.

KEYWORDS:

• Amphibia
• digital recorders
• environmental factors
• subtemperate climate

Acknowledgements

This study was supported by the Research Support Foundation of the State of Rio Grande do Sul (FAPERGS) and the Coordination for the Improvement of Higher Education Personnel (CAPES) under the FAPERGS/CAPES 09/2012 grant. S. Cechin is grateful to CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for the research fellowship (process no. 309095/2016-6). We are also grateful to ICMBio-IBAMA (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis) for providing the sampling permission (licence no. 37007-1). We are grateful to M. T. Hartmann and P. A. Hartmann for providing comments on an earlier version of this manuscript. To the anonymous reviewers for their helpful comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [309095/2016-6]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [09/2012].