Status van de Nederlandse otter-populatie: genetische variatie, mortaliteit en infrastructurele knelpunten in 2021

Samenvatting

The Dutch otter population is surveyed each year for the Ministry of Agriculture, Nature and Food Quality to monitor its genetic status. Particular attention is given to roadkill mortality and a possible reduction in genetic variation as a result of inbreeding. The aim of the annual survey is therefore twofold: a) to closely monitor the genetic variation within the population, and b) to identify and localize roadkill hotspots.The total number of verified dead otters found in 2021 was 132 (of which 117 were roadkill victims), which for the first time was a lower amount than in the previous year. The most likely explanation for this is a temporary reduction in traffic intensity as a result of the Covid-19 measures. The main roadkill hotspots were identified for each province in the Netherlands within the distribution area of the otter population.From DNA profiles obtained from roadkills it can be concluded that the total genetic variation within the Dutch otter population is reasonably stable. However, to maintain genetic variation on the longer term, it will be important to get a better view on the existence of genetic exchange with neighbouring populations in Germany and Flanders.