Evaluation de l'efficacité d'un piège photographique pour l'étude des amphibiens par capture - marquage - recapture

Abstract

The capture-mark-recapture (CMR) method has emerged as a reference method for studying amphibian population dynamics. It involves individualization which, for some species, can be based on photographs of marks naturally present on individuals. Currently, the implementation of a study based on a CMR requires the capture and the handling of individuals, which is laborious and source of disturbance for individuals and their habitat. In this article, we evaluate the effectiveness of the Newtrap camera trap (Patent LU93388). This tool automatically produces ventral images of amphibians in the field without capturing or handling them. Six Newtrap camera traps were used in a study based on a CMR to assess the occupation parameters of a pond in the Grand Duchy of Luxembourg by a population of crested newts (Triturus cristatus) during the 2019 breeding season. The results were compared with those of a reference technique (funnel traps) applied simultaneously to the same population. Overall, the results show a similar population size estimate using the Newtrap or the funnel trap method. In detail, the dynamics of entry and exit of the pond as well as the capture rate and the number of individuals captured differ according to the method. The results obtained with the funnel traps method seem to be more in accordance with the scientific literature. However, the use of the Newtrap camera trap makes it possible to carry out a study based on a CMR in a much faster and more animal-friendly way. The presence of trap-dependence and transience in datasets may have introduced a bias in model selections. Among the possible solutions, it could be considered to model the trap-dependence or remove the transience in the dataset by removing all the first captures of individuals.