MORTALIDAD POR ATROPELLO VEHICULAR Y DISTRIBUCIóN DE ANFIBIOS Y REPTILES EN UN BOSQUE SUBANDINO EN EL OCCIDENTE DE COLOMBIA

we studied the mortality of amphibians and reptiles due to motor vehicles in a segment of 2.4km along the buga-buenaventura road. this road crosses the forestal reserve bosque de yotoco, a fragment of sub-andean forest in the western andes of colombia. we also recorded the variation in composition and structure of herpetofaunal assemblages from areas close to the road versus areas away from the road (forest interior). we found a mortality rate of one vertebrate every 3-4 days; 50% were amphibians, mostly reptiles (snakes, 0.047 individual/day/km). amphibians appeared to be more susceptible than the reptiles to road disturbance. amphibian richness was higher away from the road, in areas of forest interior (seven species) than in areas close to the road (four species), while reptiles exhibited an opposite pattern (twelve species close to the road versus eight species in the forest interior). five species of amphibians and reptiles were recorded exclusively in areas near the road, five species exclusively in the forest interior, and eleven species in both areas. we discuss changes in distribution of species as a consequence of alteration in microclimatic characteristics and vegetal complexity in areas in proximity to the road, but other factors may have an influence as well (e.g., noise, pollution).