Situation of federal American mink (Neovision vision) in Catalonia: expansion, distribution, ecology and population control

Abstract

We studied the expansion and ecology of the American mink in Catalonia (NE Spain) using 2567 records of the species collected between 1974 and 2014 as part of the National Control Project and previous literature data. The species expanded from occupying one 10×10-km cell located in northern Montseny in the 1970s to 159 cells of the same size in 2014. The average expansion rate was 0.39 cells/year at the start of the invasion, but it increased to 0.91 cells per year in the last five years. The species currently occupies more than 2770 km of river and 2 km2 of wetlands, with an estimated population size of between 5725 and 8390 resident adults. Nevertheless, annual mortality in the population is high (50%) with a high turnover rate (average of 5-6 foetuses per female) and few individuals living to 4-5 years. The distribution of the species is best explained by the availability of prey and resting sites, as well as other environmental factors such as distance to rivers, land-use diversity, summer and annual rainfall and the minimum annual temperature. The diet of the species was composed mainly of small mammals, birds, fish and crayfish, with seasonal differences. American mink poses a serious threat to native biodiversity, such as the European mink and European polecat in Europe and Catalonia, respectively. The control project is still ongoing but more systematic work is needed to increase the effectiveness of the platform traps to reduce the invasive species and safeguard the native ones.