Efeito de cercamentos sobre a mortalidade de fauna na rodovia BR-262/MS

Abstract

Wildlife-vehicle collisions impact animals and their populations, as well as put human safety at risk. Structures that aim to prevent animals from accessing the road are a potential solution to this problem, but their effectiveness is highly variable. This study aims to assess whether the long and short lengths of fencing installed on the BR-262/MS highway had any effect on the mortality of the species recorded. Through a BACI (Before-After Control-Impact) sampling design, with records obtained over six years of systematic monitoring, we compared carcass counts before and after fencing, as well as fenced stretches of road and control stretches without mitigation, using generalized linear mixed models (GLMM). The results indicate that the long stretches of fencing led to a significant reduction in the mortality of yacare caimans (Caiman yacare) – while there was a 20% increase in mortality along the control stretches, fenced stretches showed a 70% reduction. However, these fences were not effective in reducing the general mortality rate of wild animals along these mitigated stretches. To improve the effectiveness of fences, since this is species-dependent, target species must first be chosen so that the location, extension, and model of fences adequately address the particularities of each species. Furthermore, to maintain the integrity of the fences, continuous maintenance of the structures and quality communication with the local community are essential. Even so, to reduce the general mortality of wild animals on the highway, there must be careful planning with well-defined goals and multiple strategies to reduce collisions with the different target species. Long-term monitoring of roadkill is fundamental for the periodic evaluation of the installed structures and the identification of possible adaptations. Lastly, to incorporate scientific and technological knowledge in the planning phase, there needs to be more of a connection between researchers, environmental analysts, and decision makers, as well as political will so that the problem of vehicle collisions can be truly addressed.