ABSTRACT Amphibians inhabiting agricultural areas are constantly exposed to large amounts of chemicals, which reach the aquatic environment during the rainy season through runoff, drainage, and leaching. We performed a comet assay on the erythrocytes of tadpoles found in the surroundings of agricultural fields (soybean and corn crops), where there is an intense release of several kinds of pesticides in different quantities. We aimed to detect differences in the genotoxic parameters between populations collected from soybeans and cornfields, and between them and tadpoles sampled from non-agricultural areas (control group). Tadpoles collected from ponds located at soybean fields had significantly more DNA damage, followed by tadpoles collected from cornfields. In contrast, animals sampled from non-agricultural areas had the lowest incidence of DNA damage. In addition, we found a negative correlation between the parameters of the comet assay and the area of the ponds surrounding soybean. This correlation indicates a possible dilution effect in the concentration of pesticides. Finally, Physalaemus cuvieri Fitzinger, 1826 seems to be a good bioindicator for detecting the genotoxic effects of field agricultural insecticides; therefore, we suggest that this species should be used in environmental biomonitoring studies, since it is common and abundant where it occurs.

A diversidade biológica e os processos ecológicos do bioma Cerrado ainda são pouco conhecidos. Neste estudo são apresentadas informações acerca da estrutura da anurofauna do município de Barro Alto, estado de Goiás (Brasil Central). Cinco corpos d'água foram amostrados entre os anos de 2007 a 2010 (outubro-março), três deles associados à área florestal e dois associados à área aberta. Registraram-se 39 espécies de anuros, caracterizados como especialistas de hábitat aberto, florestal ou generalistas. A curva de acumulação de espécies apresentou a formação de uma assíntota, evidenciando que as técnicas e esforço de amostragens foram adequados para se estimar a riqueza de espécies de anuros na região. A riqueza foi influenciada pela umidade e temperatura, já que a maioria das espécies se reproduz na estação quente e chuvosa. Diferenças significativas na composição de espécies entre os sítios reprodutivos de áreas florestais e abertas foram registradas. A fauna de anuros no Cerrado parece ser constituída a partir da heterogeneidade horizontal dos hábitats no espaço. Assim, hábitats contrastantes no espaço são importantes para a manutenção da riqueza da anurofauna, e portanto, relevantes em termos conservacionistas.

The biological diversity and ecological processes in Cerrado biome are still poorly understood. Herein we present information about anuran species of the municipality of Barro Alto, state of Goiás (Central Brazil). Five water bodies were sampled between the years 2007 and 2010 (October-March), three of them associated with forested area and two with open areas. We recorded 39 anuran species, characterized as open habitat specialists, forest habitat specialists and generalists. The rarefaction curve shows an asymptote formation, which demonstrates adequate effort and sampling techniques to assess the species richness of the region. Species richness was influenced by air humidity and temperature, since most of the species reproduce in the rainy season. We found significant differences in species composition between breeding sites in open and forested areas. The anurofauna in Cerrado seems to be formed from habitat's horizontal heterogeneity in space. Thus, contrasting habitats in space are important for maintaining the anuran richness, and therefore relevant in conservation terms.