Using population genetic structure of an invasive mammal to target control efforts: an example of the American mink in Scotland

The detrimental effect of invasive species on native ecosystems is well established and motivates management strategies to reduce their impact. Eradication can be difficult in mainland areas but control is often a feasible option, providing recolonisation of control areas is minimised. Molecular genetic techniques can be used to define management units in invasive populations and these can be used to target efforts effectively for invasive species control. The American mink is an invasive predator in many countries following introduction through fur farming. Its colonisation of a variety of habitats has devastated many native bird and small mammal populations thus control is of utmost importance. The spread of mink throughout Scotland, UK, is reasonably well documented and projects designed to manage mink are currently underway. In order to provide practical advice for mink management both in Scotland and elsewhere, over 500 mink were genotyped at 12 microsatellite loci to resolve genetic structure, delimit populations and establish patterns of connectivity across areas. STRUCTURE-based analyses identified mink populations in the west and east of Scotland as belonging to different genetic clusters and variation in gene flow between populations was found within and between these clusters. Landscape features were shown to affect the rate and direction of colonisation, with mountains restricting and valleys facilitating dispersal. Recommendations for reducing the distribution of mink in Scotland, based on these findings, are provided which can be applied to both mink and general invasive species control.