| Summary: | The contribution of Arctic wildlife to global biodiversity is substantial. The region supports globally significant populations of birds, mammals and fish. For example, over half of the world’s shorebirds and 80% of the global goose population breed in Arc- tic and Sub Arctic regions. Dramatic changes (e.g., sea-ice loss) in the Arctic’s ecosystems are predicted to occur over the next century. Arctic species that have adapted to these extreme envi- ronments are expected to be displaced by the encroachment of more southerly (Sub Arctic) species and ecosystems. Continued, rapid change in the Arctic ecosystems will have global repercus- sions affecting the planet’s biodiversity as a whole. Understanding how the Arctic’s living resources, including its vertebrate species, are responding to these changes is essential in order to develop effective conservation and adaptation strategies. In this report, vertebrate population-abundance data were used to produce an indicator of the trends in Arctic biodiversity over the past 34 years (1970 as the baseline1). This index tracks 965 populations of 306 species, representing 35% of all known vertebrate species found in the Arctic. Vertebrate abundance in High Arctic species declined 26% between 1970 and 2004. Low and Sub Arctic species have fared better over this time period: Low Arctic species experienced increasing abundance and Sub Arctic species showed a decline since the mid-1980s, but no overall change over the 34-year period. These observed trends are largely consistent with current predictions regarding the response of Arctic wildlife to climate change and expected increases in previously over-harvested species, and suggest that human-induced changes in Arctic ecosystems are already result- ing in winners and losers. Dramatic growth of certain popula- tions of migratory Arctic-nesting geese species, for instance, shows a contrast with a steady decline in other herbivorous species, most of which are not migratory. While this report highlights trends seen over 34 years, ...
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