Man-made infrastructures as accidental traps for herpetofauna in eastern Spain: incidence and modelling

Water supplies in arid regions have traditionally been assured by cisterns, channels, wells, among other man-made structures with smooth vertical walls that can be deadly traps for several animals, including  amphibians and reptiles. In this study, we investigate the incidence of such “trap structures” on the herpetofauna of the eastern Iberian Peninsula. We explored which features of these structures and which biological traits are associated with higher incidence of falling into these traps. We studied 205 trap structures and found 1,224 amphibians or reptiles representing 25 different species, including endangered and protected ones. Broad-scale macroclimate and landscape variables were not associated with the incidence of traps. Instead, trap impact was influenced mainly by trap morphology and season of the year, which suggests that construction design and species phenology are the main factors to affect the incidence of a trap. Biological traits (subterranean or aquatic habits, diet, nocturnal activity or emission of reproductive calls) in some species were related to the probability of falling into these traps. Some species of snakes, lizards, and toads were more prone to fall in trap structures than other species. We conclude that trap structures can strongly impact amphibian and reptile survival, especially in arid or semi-arid regions where wells and water cisterns are widespread.