Fluxes of dissolved organic and inorganic nitrogen in relation to stand characteristics and latitude in Scots pine and Norway spruce stands in Finland

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.