Look before you cross the road: herpetofauna roadkill hotspots in a Mexican Biosphere Reserve

The principal impacts of road infrastructure on wildlife include biodiversity loss, habitat fragmentation, increased human presence, and the creation of barriers or boundaries. These effects can have significant repercussions, particularly for amphibians and reptiles. In tropical ecosystems, information on the impacts of roads within Protected Natural Areas (PNA) is limited. Therefore, this research seeks to identify hotspot areas exhibiting high mortality rates among herpetofauna within and outside the Selva El Ocote Biosphere Reserve, Chiapas, Mexico. Given the biological characteristics of herpetofauna, particularly their ectothermic nature, coupled with the relatively more pristine vegetation within the PNA, it is anticipated that the most significant incidence of roadkill will occur within the PNA limits. In this regard, 20 road surveys were conducted along 5-km transects on two highway corridors from July 2019 to March 2020. A total of 140 instances of road mortality among herpetofauna were documented, comprising 52 amphibians and 88 reptiles. The kilometric index for global roadkill abundance was calculated to be 0.28 roadkilled individuals per kilometer. Furthermore, six roadkill hotspots were identified within the Selva El Ocote Biosphere Reserve, three outside the reserve boundaries. The critical regions identified in this study encompass a variety of endangered (5) and native species (2). These locations, which exhibit elevated mortality rates among herpetofauna, will serve as the basis for developing strategies to mitigate the impact of roadways on these taxa within Selva El Ocote.