RESUMO
The sensitivity of anuran to the effects of habitat destruction and contamination has led to a preoccupying global decline in their populations. Morphological biomarkers such as micronuclei and other erythrocyte nuclear abnormalities (ENAs), as well as the occurrence of hepatic melanin, can be used to evaluate the effects of habitat impacts. In the present study, these two parameters were combined for the in situ assessment of the effects of soybean cultivation on the grassfrog, Leptodactylus fuscus. Specimens were also collected from a protected area to provide a reference site (non-agricultural environment). The frequency of some of the nuclear abnormalities in the animals from the soybean plantation was much higher than that recorded at the reference site, in particular micronuclei, which were 3.6 times more frequent in the plantation, lobulated nuclei (3.4 times more frequent), and reniform nuclei, which were four times more common than at the reference site. The combined analysis of all the ENAs together also revealed a frequency approximately 1.4 times higher in the animals from the soybean plantation, in comparison with the protected area. Smaller areas of hepatic melanin were observed in the specimens from the soybean plantation. These results provide further evidence of the sensitivity of anurans to habitat impacts and indicate that animals found in soybean plantations are susceptible to systematic alterations of their cells.