Abstract:
The Pan-American Highway in Costa Rica is currently undergoing expansion in capacity as a response
to growth in vehicle traffic associated with growing international trade. This highway bisects the Pacific lowlands
Tropical Dry Forest of the Guanacaste Conservation Area, a World Heritage site of the United Nations Educational,
Scientific and Cultural Organization, with notably high biodiversity, including herpetofauna. As wildlifevehicle collisions are one of the main direct causes of animal mortality, we quantified the species composition,
seasonality, and location of amphibians and reptiles killed along a 30 km segment of the highway running through
the conservation area. From August 2016 to February 2017, we mapped roadkill hotspots using Kernel Density
Estimation (KDE) with KDE+ software. We detected 1,298 carcasses of 28 species, including seven anuran, one
caecilian, three lizard, 15 snake, and two turtle species; the Neotropical Yellow Toad (Incilius luetkenii) comprised
over half the total roadkill. The two most severe roadkill hotspots were short road segments near seasonally flooded
depressional wetlands where I. luetkenii and other anurans breed. We urge construction of mitigation measures
including barriers and subterranean passages to conserve amphibian populations, especially if the Pan-American
Highway will be widened at these sites.
