A influência da intensificação do ciclo agrícola na diversidade de anuros (amphibia, anura) em arrozais no Sul do Brasil

Abstract

Wetlands are sources of natural resources for human beings and are among the most productive ecosystems in the world. However, approximately 50% of these ecosystems have disappeared in the last century, and one of the principal causes of this disappearance is the conversion of natural wetlands into rice plantations. These systems thus serve as a final refuge for many species that depend on the characteristics of these wetlands, such as amphibians. In this study, we evaluate and compare the structure (abundance of tadpoles and richness and composition of adults and tadpoles) of the frog community between irrigated rice fields under different levels of agricultural intensification (with or without a fallow season) in southern Brazil. We selected six fields of irrigated rice (three with fallow seasons and three without) and three natural wetlands. We documented 15 species of frogs between the tadpoles and adults. We identified 188 tadpoles, which were distributed among four families and 13 species. Of this total richness, three species were found only during the larval phase (Physalaemus gracilis, Scinax perereca and Rhinella fernandezae). However, Odontophrynus maisuma and Pseudis minuta were only observed as adults. According to this data, species richness and composition are significantly distinct among the sampling locations. Although the abundance varied among treatments, the difference was not significant. Our results show that intensification in the cultivation cycle influences frog communities, and a resting period should be included in the management of these areas so that they can harbor a larger and more diverse community of frogs.