Mammal use of some crossing structures in a Federal Highway in Jalisco, México

Abstract

Since the construction of Federal Highway 200 in the coast of Jalisco, México, there have been environmentally detrimental processes along its length. With no wildlife crossing structures built at the time, mammal connectivity has been “safely” maintained through streams and rivers and their corresponding bridges.  We used photo-trapping to assess 2 bridges and 1 culvert in the vicinities of Careyes within the influence area of the Chamela-Cuixmala Biosphere Reserve from November 2020 to March 2021.  We compared bridges with upstream cameras to see whether there were differences in species richness and relative abundance.  With 736 camera / nights, we obtained a total of 421 mammal records, of which 252 were crossings of 14 mammal species,12 native and 2 introduced beneath the highway, 241 through bridges and 11 through the culvert. Upstream cameras showed higher diversity values compared to the bridges. Upstream cameras showed higher mammal diversity values compared to the bridges.  Streams and bridges serve to maintain mammal connectivity through the highway.  Ungulates might cross the highway more often than carnivores due to their reticence of going near roads.  Future wildlife crossing structures along this highway should keep this in mind.