Illegal hunting threatens the establishment of a lynx population and highlights the need of a centralized judiciary approach

摘要: O_LIIllegal hunting (poaching) represents a major threat to the conservation of large predators. Yet, its impact remains difficult quantify as there are strong incentives conceal this criminal activity. Attributing changes in population status carnivores part poaching is therefore an important challenge. C_LIO_LIWe present case study lynx (Lynx lynx) southwestern Switzerland (canton Valais) where current distribution range much smaller than it was recent past and density now >80% lower other populations Swiss Alps, particularly adjacent Pre-Alps. We tested four hypotheses explain far density: 1) too low trail camera-traps deployed for surveys Valais compared Pre-Alps (i.e. methodological artefact); 2) less favourable environmental conditions around camera-trap sites; 3) densities main prey; 4) poaching. estimated ungulate at camera sites, were able clearly reject first three hypotheses: monitoring protocol similarly effective; trapping sites even more detection Pre-Alps; prey supply larger. Concerning hypothesis 4, we discovered local, but dense network 17 illegal traps narrow immigration corridor into from thriving Pre-Alps, suggesting intense local C_LIO_LIOur findings substantiate suspicions long-lasting establishment survival population. The fact that instances publicly known since 1995 remained unabated least two decades, until conviction occurred, questions commitment authorities address wildlife crime. Our shows inquiries about crime such top predator may need be carried out highest levels jurisdiction avoid any risk collusion between law enforcement agents poachers. C_LI