Grass Rejection by Capybaras Can Be Used as a Possible Strategy to Mitigate Road Accidents

Feeding management can be a good strategy for avoiding wildlife–vehicle collisions (WVCs), which are a worldwide concern. In this study, we aimed to identify grass species that capybaras (Hydrochoerus hydrochaeris) reject as feeding material. These species could be planted to make roadsides less attractive to capybaras and, consequently, decrease WVCs involving this species. We planted 3 grass species (Brachiaria decumbens cv. Basilisk, B. hybrid Mavuno, and Zoysia japonica) in 4 blocks, applying a randomized-complete blocks design. The first 2 species we assumed would be rejected, since some animals do not consume them due to their high levels of chemical secondary compounds, such as saponin. The third species is the grass currently planted on roadsides in the state of São Paulo, Brazil. All blocks were surrounded by an electrified fence that was removed for collecting data on capybara grass consumption. To estimate the consumption or growth of each grass species, we determined the difference between the initial and the final height of grass, measuring 180 swards, 1,336 leaves, and 240 tillers after capybaras had cleared access to the blocks. We also recorded capybara behavior for 3 days using infrared video cameras. Our data showed that the consumption of Z. japonica was higher than that of B. decumbens cv. Basilisk and B. hybrid Mavuno (P P = 0.770). Z. japonica seems to be a palatable food source for capybaras, and so we strongly recommend the removal of this species from roadsides. As capybaras showed almost no consumption of B. decumbens cv. Basilisk or B. hybrid Mavuno, we recommend planting either of these species on roadsides to decrease their attractiveness to capybara and hence to decrease the risk of WVCs.