Plastron color patterns allow for individual photo-identification in two different chelonian species

Abstract

Natural marks have increasingly been used as a tool for individual identification in capture–mark–recapture techniques. Photo-identification is a noninvasive alternative to traditional marking techniques, allowing individual recognition of species through time and space. We tested the APHIS (Automatic Photo Identification Suite) software as a software capable of identifying individuals of Hermann’s Tortoise ( Testudo hermanni Gmelin, 1789) and European Pond Turtle ( Emys orbicularis (Linneaus, 1758)) in different populations during capture–release sessions in the field based on plastron color patterns, since they can be used as natural marks for identification. For this individual identification, spot pattern matching (SPM) and image template matching (ITM) procedures were tested, achieving 100% success of individuals recognized in both procedures and visually verified by comparing the images. However, the ITM procedure was more efficient at recognizing recaptures than SPM because ITM allowed faster recapture verification, since most of the matches were directly placed in the first position on the candidate list. Previous studies used photo-identification on freshwater or sea turtles but never with terrestrial tortoise species. Consequently, it was corroborated that APHIS is a competent and efficient software considering photo-identification of T. hermanni and E. orbicularis, and that it can be applied to close species with similar and unique individual color patterns in their plastron.