Where have all the young wolves gone? Traffic and cryptic mortality create a wolf population sink in Denmark and northernmost Germany

• Published in: Conservation Letters
• Main Authors: Sunde, Peter, Collet, Sebastian, Nowak, Carsten, Thomsen, Philip Francis, Hansen, Michael Møller, Schulz, Björn, Matzen, Jens, Michler, Frank Uwe, Vedel-Smith, Christina, Olsen, Kent
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Canis lupus; Denmark; genetic wildlife monitoring; Germany; human–wildlife conflict; illegal killings; large carnivores; poaching; recolonization; roadkills; source–sink
• Online Access: https://pure.au.dk/portal/en/publications/902a28f1-b4a0-4626-8f09-e66eb2b725d6; https://doi.org/10.1111/conl.12812; http://www.scopus.com/inward/record.url?scp=85105802319&partnerID=8YFLogxK

Large carnivores are currently recolonizing Europe following legal protection, but increased mortality in landscapes highly impacted by humans may limit further population expansion. We analyzed mortality and disappearance rates of 35 wolves (of which three emigrated, nine died and 14 disappeared by 1 January 2020) by genetic monitoring in the heavily cultivated and densely populated Jutland peninsula (Denmark and Schleswig-Holstein, Germany). Annual traffic kill rate estimates ranged from 0.37 (95% CI: 0.11–0.85) to 0.78 (0.51–0.96) in the German part, equivalent to 0.08 (0.02–0.29)–0.25 (0.13–0.46) for the entire region, in the absence of any registered Danish roadkills. In Denmark, annual mortality rate estimates ranged from 0.46 (0.29–0.67) to 0.52 (0.35–0.71), predominantly from cryptic mortality. Despite successful reproductions, we conclude the region is a wolf population sink, primarily driven by cryptic mortality, most likely illegal killing. We hypothesize that frequent encounters between wolves and wolf-averse persecutors in cultivated landscapes may cause unsustainably high mortality rates despite the majority of hunters respecting protection laws.