Herpetofauna and roads: a review
Roads and traffic are tightly related to some of the mains threats for biodiversity. Road network affects wildlife populations due to, among other effects, partial occupation and transformation of landscape, alteration of surrounding habitat, dispersal of physicochemical pollutants, fragmentation and loss of connectivity, or direct road-kills. Because of their ecological characteristics, amphibians and reptiles are very exposed to road effects. In this article we review the relationship between these faunal groups and the road network. Amphibians exhibit high road-kill rates that can condition viability of some populations, and are vulnerable to pollution of road margins. Reptiles also suffer casualties because of road-kills when they move to paved roads for thermoregulation. Roads, especially those with high traffic load, act as barriers that difficult movements and contribute to population isolation in both groups. However, road impacts do not have equal intensity over space and time, and consequently some spatio-temporal patterns can be defined. Not all species show the same degree of exposure to road impacts, which depend on specific ecological requirements in each case. Mobile species are generally more vulnerable than sedentary ones. There are also intra-specific differences as a function of gender and age. All these considerations must be taken into account when designing and implementing the corresponding mitigation measures necessary to reduce the negative effects of roads on herpetofauna populations.