Northern deer. Photo: Oleg Kozlov/shutterstock.com

The latest Arctic Report Card (ARC), released December 2012 by the National Oceanic and Atmospheric Administration (NOAA) with contributions from the Conservation of Arctic Flora and Fauna (CAFF)’s Circumpolar Biodiversity Monitoring Program (CBMP), highlights “profound and continuing changes” in the Arctic marine ecosystem, a greening of the Arctic, and some alarming trends in shorebird species, along with other stories of how Arctic wildlife are responding to environmental changes.

The chapters in the report highlight meaningful detectable changes of regional, continental and global significance, suggest key factors responsible for the changes (be it climate, anthropogenic or both) and illustrate the connections between the Arctic marine and terrestrial ecosystems.

The terrestrial section has five chapters that focus on primary producers (vegetation), herbivores (lemmings and caribou/reindeer) and predators (Arctic fox). Another essay highlights changes in Arctic migratory wader (shorebird) populations, which introduces and emphasizes the influence of southern stressors and drivers on Arctic wildlife.

The marine section has six chapters discussing productivity and nutrients, benthos, seabirds, fish and fisheries, marine mammals and a focus on the Barrow Canyon as a region for change detection.

A greening Arctic 

Dryas octopetala. Photo: zimowa/shutterstock.comOver the past 30 years, the typically white landscapes of the Arctic have been turning green, a sign of increased plant cover as a result of warming temperatures. 

The North American Arctic has become 15.5 per cent more green while the Eurasian Arctic has increased 8.2 per cent, according to the Normalized Difference Vegetation Index (NDVI). The greatest “greening” has occurred in the southern most tundra, where biomass has increased 20-26 per cent. Shrubs, grasses and even some flowering plants are expanding their ranges into the Arctic, and the growing season is getting longer.

 

 

 

 

Sharp and alarming declines in some shorebird populations 

Shorebirds. Photo: Jan van de KammMore than 40 per cent of Arctic waders are in decline, with just nine per cent increasing, according to the report. 

Arctic shorebirds migrate to almost all corners of the world, along extensive migratory corridors, or flyways. When analyzed along their migratory paths, clear and worrying pictures can be apparent, especially as they are good indicators of overall global coastal ecosystem health.

The African-Eurasian flyway is the most stable, with one-quarter of the 46 shorebird populations in decline. In North America, 56 per cent of the 34 populations are in decline. In Central Asia trends are known for only three of 20 populations, and are thought to be stable. In East Asia, all populations with known trends are declining. Hunting, harvesting, pollution and habitat loss are contributing to these dramatic declines.

Unknown effects on Arctic land mammals

Arctic fox. Photo: Carsten Egevang/ARC-PIC.comThe ARC identifies that lemmings are a key species in the Arctic, as their numbers can dramatically alter the composition of the tundra food web, including the productivity of birds and mammals that depend on them for food. The regularity and predictability of lemming population cycles is decaying. Recent studies suggest a link between changes in the lemming population cycle and changes in the characteristics of the snow pack, e.g., duration and number of ice layers, and the subsequent impact on ground conditions, e.g., temperature and ice layers.

The Arctic fox is most directly affected by lemming population dynamics as it is a primary food source. In the European Arctic, the Arctic fox has declined to near extinction because it has not recovered from historical over-harvesting and recent lemming declines. Just 200 individuals remain, compared to over 15,000 in the mid-1800s. In North America, the Arctic fox is abundant. In both regions, the red fox has expanded northward into historic Arctic fox-only territories. The red fox, twice the size of the Arctic fox with about twice the home range area, affects the Arctic fox via competition for resources and predation. 

The ARC also indicates that caribou/reindeer populations appear to be within their natural ranges, and many herds that have experienced declines are beginning to stabilize or increase.

 

Effects of sea-ice loss 

Sea ice. Photo: Carsten Egevang/shutterstock.comThis year the Arctic summer sea ice extent hit a record low. Sea ice is an important regulator primary productivity, and affects the abundance and composition of algae and phytoplankton, the elements that kick-start the marine food web. New satellite observations suggest that previous estimates of annual primary production in waters may be about ten times too low in places.

Shifts in primary and secondary production have direct impacts on benthic communities. Recent findings include: species range changes in sub-Arctic seas and on inflow shelves; changes in feeding guild composition in the deep Fram Strait; reduction of benthic biomass in the Barents and northern Bering seas; and no apparent change in infaunal biomass in the Kara Sea. Recent sea ice declines have allowed gray whales to stay longer and feed on both benthic amphipods and zooplankton in the Barrow Canyon region of northwest Alaska.

Seabirds, long considered a valuable indicator of changing marine conditions, are showing changes in phenology, diet, foraging behavior and survival rates across the Arctic. Seabirds, it is believed, are responding, at least in part, to warming sea surface temperatures and concurrent changes in prey availability. 

 

 

Management and response

CAFF’s Arctic Biodiversity Assessment (ABA) work is highlighted in another section of the ARC. It summarizes what is known about population sizes, trends and distributions for species that inhabit sub-Arctic and Arctic waters. The ABA will create a baseline of information which will be constantly fed by the CBMP to improve rapid detection of system perturbations and provide scientific understanding to support decision-making.

NOAA scientist conducting benthic sampling. Photo: Bodil Bluhm/NOAA

New programs are underway to more effectively measure, monitor and document changes in the marine ecosystem. The Distributed Biological Observatory (DBO) is an international change detection array for the identification and consistent monitoring of biophysical responses in the Pacific Arctic. One essay highlights provisional results from a production ‘hotspot’ in Barrow Canyon, which was investigated during the DBO pilot program.

During International Polar Year (2007-2009), the first coordinated, year-round sampling of underwater acoustic marine mammal habitats at two sites in the high Arctic documented the seasonal occurrence of both Arctic and sub-Arctic species in Fram Strait (Atlantic Arctic), but only Arctic species on the Chukchi Plateau (Pacific Arctic). The Fram Strait recorders also discovered that Spitzbergen’s bowhead whales were singing almost continuously through the winter, suggesting that this critically endangered population may be larger than previously thought and that Fram Strait may be an important over-wintering area for it.

 

Contact 

Mike Gill

Chair

Circumpolar Biodiversity Monitoring Program

+1 867 334 3258

Mike [DOT] gill [AT] ec [DOT] gc [DOT] ca 

 


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