Effect of toe-clipping on the survival of several lizard species

Abstract

ABSTRACT: Toe-clipping is an extensively used technique for individual identification of amphibians and reptiles. However, this method might result in negative effects including reduced survival. In this study, we used capture-mark-recapture data obtained from ten different lizard species, including more than one population for two species, to examine whether survival rates varied as a function of the number of toes that were clipped. We used likelihood methods and multi-state models to estimate survival probabilities. Specifically, we tested if the number of clipped toes had an effect on annual survival, comparing survival among groups of individuals that shared the same number of toes that were clipped. We found clear reductions in survival associated with the removal of several toes in seven study sites that correspond to five different species. These represent 37% of all the species and populations that we examined. Therefore, we conclude that this marking method potentially causes severe damage and may lead to biased parameter estimates in ecological studies of lizard species. Whenever possible, toe-clipping should be avoided and replaced by less invasive methods for individual identification.