Biodiversity Effects: Prey

One of the biggest conservation issues surrounding invasives is the impact they have on native species. The American mink has had major effects on European biodiversity, as the mink prey on many native species, such as ground-nesting birds, waterfowl, the water vole and some reported amphibians and snakes. 

We've already explored the biology of the American mink which makes it a good invader. This same biology is what causes mink to have such a large impact on the biological viability of European ecosystems.

Mink use unusual method of surplus killing, killing more than it needs to survive. This greatly affect its prey populations. Mink have tended to establish themselves in the wild in the places with “high prey biomass that can sustain mink” (Bonesi et al., 2007) 

Waterfowl and ground-nesting birds

Velvet Scoter: common prey of American mink in Finland

Waterfowl and wetland ground-nesting bird populations have been greatly affected by the predation of American mink. There are studied decreasing populations of waterfowl in Czech Republic, Estonia, Iceland, Ireland, Latvia, Lithuania, Poland, Sweden and the UK (Bonesi, 2007). Presence of American mink was found to significantly decreased the number of moorhen and coot pairs (Ferreras et al., 1999). Many ground-nesting sea-birds are threatened easily because they typically lack terrestrial predators in their, and therefore they have little defensive behavior to protect themselves in the presence of American mink (Kauhala, 1996). Studies in Finland show that American mink affect the smaller water fowl, such as the mallards and other ducks. (Nordstrom et al., 2002). American mink limiting breeding population densities and therefore reducing genetic diversity in the waterfowl communities. The waterfowl populations were shown to reestablish themselves after the removal of American mink.

Water vole (Arvicola amphibius)

European water vole

  Overtime, at sites in the river Thames in England, European
water vole populations decreased as American mink populations increased.
Courtesy of (MacDonald et al, 2003)  

Water vole populations have been declining in rapidly as they are a common prey of the American mink. In the UK, water vole has declined 97% since 1900, mostly due to the mink (Bonesi, 2007). American mink have had such a large effect on water voles because they have a preference for small mammal prey (MacDonald et al., 2003). Water voles are also innately afraid of the mink's odor and do not have any "anti-predator adaptations" that are effective against American mink. In one study, there were no signs of American mink at any sites where water vole persisted (MacDonald et al., 2003). 

Other prey

• salmonoids/fish 
• the effect on salmonoids is unclear and needs to be further researched
• rabbit
• American mink eat large amount of rabbits in England
• however, rabbits are very abundant so this does not pose a problem for rabbit populations (Kauhala, 1996)
• reptiles & snakes
• more studies need to be completed
• many aquatic species are hunted, but mink do no have a significant impact on the prey's population size (Melero et al., 2012)
• Check out mink hunting videos here