Long-Term Changes in Survival of Eurasian Lynx in Three Reintroduced Populations in Switzerland

Abstract

For conservation or management programs, basic data on vital rates are important but often hard to acquire for long-lived and elusive wildlife species such as large carnivores. In this study, we analyzed long-term changes in survival rates for different sexes and age classes (juvenile, subadult, adult) in three reintroduced Swiss lynx populations (Alps, Jura, Northeastern Switzerland). A novel modeling approach allowed us to combine picture data from camera trapping and lynx pictures resulting from chance observations, telemetry data, and dead recoveries over a monitoring period of 25 years (1997–2022). Mean annual survival of adult lynx varied between 0.71 and 0.81 for males and between 0.70 and 0.85 for females. Mean survival of subadults ranged between 0.59 and 0.89 among populations. Juvenile survival was highly variable and low on average (< 0.4). Our findings highlight that unknown sources of mortality exist in some populations and that future studies on mortality causes and potential effects of inbreeding on survival are needed to ensure long-term conservation of the lynx in Switzerland. Our study can serve as a basis for future studies on population viability and conservation threats to the species in human-dominated landscapes and demonstrates the complexity and high variation of survival between different age and sex classes in space and time, potentially leading to source-sink dynamics.