| Videos &, photos: |
Terrestrial Ecosystems Summary
Section Coordinators: D. A. "Skip" Walker1 and Mike Gill2
1University of Alaska Fairbanks, Fairbanks, AK, USA
2Canadian Wildlife Service, Environment Canada, Whitehorse, YT, Canada
& Conservation of Arctic Flora and Fauna (CAFF) / Circumpolar Biodiversity Monitoring Programme
November 10, 2011
The Terrestrial Ecosystem section of the 2012 Arctic Report Card illustrates the interconnections between the Arctic marine and terrestrial ecosystems. An example is the direct link between increases in Arctic tundra vegetation productivity and earlier peak productivity in many parts of the Arctic on one hand and increasing duration of the open water season and decreasing summer sea ice extent on the other (see the essay on Sea Ice).
The Normalized Difference Vegetation Index (NDVI) shows that there is a long-term trend of increased biomass production in many parts of the Arctic. Over the whole Arctic from 1982 to 2010, the maximum summer NDVI increased by an average of 8%. However, there is considerable spatial variability, ranging from a 26% increase in lands adjacent to the Beaufort Sea to a small decline in several areas. The areas of greatest increase appear to be correlated with adjacent coastal areas that have experienced dramatic retreats in summer sea ice extent (see the essay on Sea Ice). Despite these long-term trends, annual variation is significant. In 2009, circumpolar NDVI showed a dip that corresponded to elevated atmospheric aerosols and generally cooler summer temperatures over the Arctic. Then, in 2010, NDVI rebounded strongly in North America, but less so in Eurasia. Information from long-term ground-based observations shows that, in addition to increasing air temperatures and loss of summer sea ice, widespread greening is also occurring in response to other factors. These include landslides and other erosion features related to warming permafrost, tundra fires and factors related to increased human presence in the Arctic.
The impacts of increased biomass production in Arctic tundra ecosystems on arctic wildlife are unclear. Despite changes in tundra biomass, migratory barren-ground caribou appear to be within known ranges of natural variation, with many herds that have experienced declines in the past decade beginning to increase or stabilize. Despite this, rapid environmental and social changes in the Arctic are a concern.
Photograph of Arctic landscape courtesy of Vladimir Romanovsky.
