Stable isotopic composition of Bothrops atrox (common lancehead) in four distinct land covers in eastern Amazonia

Since consumers reflect the isotopic composition of an assimilated diet, stable isotopes can be a useful tool to address the feeding ecology of tropical snakes. This is the first study reporting carbon and nitrogen stable isotopic composition of Bothrops atrox (Linnaeus, 1758) living in different landscapes located in the lower Amazon river, encompassing four main natural landscapes of the Amazon: old-growth forests, v & aacute;rzeas (flooded forests), savannas, and pastures. Our null hypothesis is that the delta C-13 of forest specimens of B.atrox is more negative because forests are dominated by C-3 plants, while C-4 plants are common in the other landscapes. On the other hand, delta N-15 of forest specimens should be more positive, since the delta N-15 of old-growth forests are higher than plants of savanna, v & aacute;rzea, and pastures. Confirming our hypothesis, the delta C-13 of B. atrox scales of the Tapaj & oacute;s National Forest was approximate -25 parts per thousand to -24 parts per thousand, increased to approximately -23.5 parts per thousand to -23.0 parts per thousand in the savanna and pasture, and to -21 parts per thousand in the v & aacute;rzea, showing an increased contribution of C-4-derived carbon. Some specimens of B. atrox had delta N-15 as high as 18 parts per thousand, which is much higher than the average delta N-15 of the snake's prey (7 parts per thousand), confirming the apex position of B. atrox in the Amazon region. The delta N-15 values of the forest specimens were 5 parts per thousand higher than the savanna specimens, and this difference decreased to 3 parts per thousand between the forest and the pasture, and the v & aacute;rzea specimens. Finally, there were not large differences between delta N-15 values of livers and scales in any of the landscapes, suggesting a constant diet through time, and reinforcing the possibility of the use of snake's scale as a less invasive and non-lethal tissue to analyze.