Banks, P. B., Nordström, M., Ahola, M, Salo, P., Fey, K. & Korpimäki, E. 2008: Impacts of alien mink predation on island vertebrate communities of the Baltic Sea Archipelago: review of a long-term experimental study. Boreal Env. Res. 13: 3–16.

Feral American mink (Mustela vison) are emerging as one of the biggest threats to biodiversity in northern Europe. Here we summarize responses of migratory seabirds, island small mammals and amphibians to 15 years of large-scale, experimental mink removal in the outer Finnish archipelago. Mink control led to increases in breeding populations of 14 of 22 species of seabirds, which were generally of smaller body size and later breeders as compared with those species which showed no responses. Mink also suppressed the natural summer increases of bank vole (Clethrionomys glareolus) and field vole (Microtus agrestis) populations but only during years of good rainfall. Impacts on common frogs (Rana temporaria) took seven breeding seasons to appear probably because of delayed maturation of frogs; the less palatable common toads (Bufo bufo) seemed unaffected. It appears then that the disruptive effects of mink impacts may cover the entire island vertebrate community with cascading consequences to the whole archipelago ecosystem. Ongoing research is focused on the effects of the native apex predator, the white-tailed sea eagle (Haliaeetus albicilla), whose return may suppress the detrimental effects of mink.

Gren, I.-M. 2008: Economics of alien invasive species management — choices of targets and policies. Boreal Env. Res. 13: 17–32.

The purpose of this paper is to present the economic analysis and research on invasive species management, which implies, in principle, a focus on two main questions: (i) how to set targets for species damage mitigation? and (ii) which policy instruments are best in achieving the target(s)? The results indicated that a majority of the studies recognize the need for addressing the links between economic and ecological systems and accounting for the uncertainty associated with predicting damages from invasive species. A common result is that strategies for prevention, control and damage reduction are complementary, and neglect of any of them may lead to unnecessary large social costs. Furthermore, unless economy-wide adjustments are accounted for when designing tariffs on imports, counteractive results may occur where the risk of invasive species damage increases. However, due to insufficient availability of data on the environmental impacts of alien invasive species, there is a lack of empirical applications.