Step on it: can footprints from tracking tunnels be used to identify lizard species?

Abstract

There are few effective or efficient established methods for monitoring cryptic herpetofauna. Footprint tracking tunnels are routinely used to index small mammal populations, but also have potential for monitoring herpetofauna. We evaluated the utility of tracking tunnels for identification of New Zealand lizards using captive- and wild-sourced animals (four skink and eight gecko species). All skink prints that we obtained were indistinct or obscure, but we obtained relatively clear, measurable prints for all gecko species. We found that identification to species level was possible for the two gecko species for which we had a large sample—Naultinus gemmeus and Woodworthia ‘Otago large’—using linear discriminant analysis (the best model correctly assigned 96.1% of individuals). Our findings suggest that footprints from tracking tunnels may be used to distinguish between species of geckos. Additional research is needed to assess the ability to further discriminate intra- and inter-genera lizard footprints from tracking tunnels, and the utility of the technique for surveying and monitoring lizard populations.