Non-Invasive Genetic Mark-Recapture as a Means to Study Population Sizes and Marking Behaviour of the Elusive Eurasian Otter (Lutra lutra)

摘要: Quantifying population status is a key objective in many ecological studies, but often difficult to achieve for cryptic or elusive species. Here, non-invasive genetic capture-mark-recapture (CMR) methods have become very important tool estimate parameters, such as size and sex ratio. The Eurasian otter (Lutra lutra) an species of management concern increasingly studied using faecal-based sampling. For unbiased ratios estimates, the marking behaviour otters has be taken into account. Using 2132 faeces wild Upper Lusatia (Saxony, Germany) collected over six years (2006–2012), we applied closed CMR models accounting misidentification sizes ratios. We detected difference with jelly samples being more defecated by males placed actively exposed on frequently used sites. Since are higher DNA quality, it not only concentrate this kind sites invest sufficiently high numbers repetitions non-jelly ensure Furthermore, seemed increase intensity due handling their spraints, hence behavioural response could important. provided first precise confidence intervals (for 2012: N^ = 20 ± 2.1, 95% CI 16–25) showed that spraint densities reliable index abundances. further demonstrated when minks live sympatry comparably densities, non-negligible number supposed actually mink origin. This severely bias results monitoring if genetically identified.