Supplementary material S1: GPS collars have an apparent positive effect on the survival of a large carnivore

• Main Authors: Cyril Milleret, Richard Bischof, Pierre Dupont, Henrik Brøseth, John Odden, Jenny Mattisson
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: Ecology; population level; representativeness; population dynamics; Gulo gulo
• Online Access: https://doi.org/10.6084/m9.figshare.14790458.v1; https://figshare.com/articles/journal_contribution/Supplementary_material_S1_GPS_collars_have_an_apparent_positive_effect_on_the_survival_of_a_large_carnivore/14790458

Are instrumented animals representative of the population, given the potential bias caused by selective sampling and the influence of capture, handling and wearing bio-loggers? The answer is elusive due to the challenges of obtaining comparable data from individuals with and without bio-loggers. Using non-invasive genetic data of a large carnivore, the wolverine ( Gulo gulo ) in Scandinavia and an open-population spatial capture–recapture model, we found a 16 (credible interval: 4–30) percentage points lower mortality probability for GPS-collared individuals compared to individuals without GPS collars. While the risk of dying from legal culling was comparable for collared and non-collared wolverines, the former experienced lower mortality probabilities due to causes other than legal culling. The aforementioned effect was pronounced despite a potentially lower age, and, therefore, likely higher natural mortality, of collared individuals. Reports of positive effects of bio-loggers on the survival of individuals are uncommon and we argue that GPS collars could shield animals from poaching. Our results highlight the challenges of drawing population-level inferences for populations subjected to poaching when using data from instrumented individuals.