Polar bears
Polar_bearsEstimates of polar bear populations made in 2009 indicate that of the 19 recognized polar bear subpopulations, only one is currently increasing. Of the remaining subpopulations, three are stable, eight are declining, and seven have insufficient data from which to detect a trend. As polar bears are fundamentally dependent upon sea ice, increased fragmentation and loss of sea-ice habitat as a result of climate change is one of the greatest conservation concerns for this species. Pollutants entering the Arctic via long-range transport are another issue of concern for this top predator as contaminant loads are increasing in some populations.
Wild reindeer and caribou
reindeerWild reindeer and caribou have declined by about 33% since populations peaked in the 1990s and early 2000s. While some of the smaller populations are either stable or increasing, the majority of the large herds are in decline. The major stressors contributing to declines vary between herds but climate is an important factor for many herds. For more southern herds, increased human activity and industrial development are of particular concern. The broad spectrum of changes occurring across the tundra environment may delay or slow the recovery of some herds, and some herds may disappear altogether.
Shorebirds – red knot
ShorebirdsOf the six subspecies of red knot, three are in decline and two appear to be declining, while the trend for the sixth subspecies is not clear. Although the red knot is not yet considered to be threatened globally, it is a long-distance migratory species dependent on a limited number of stopover and wintering sites, and is particularly vulnerable to habitat change along its migration routes. Climate change may be beneficial to this species in the short term if there is an earlier snowmelt and more food is available but ecosystem changes over the longer term may result in a loss of Arctic breeding habitat. The decline in red knots is representative of the overall declining trend in waders.
Seabirds – murres (guillemots)
Seabirds1Murres are among the most abundant seabirds in the Northern Hemisphere with a population in excess of ten million adults. No obvious global trend has been identified but the majority of regional populations have shown declines over the past three decades. While they are currently abundant, climate change is projected to pose problems to murres in the future, especially for the more northern species, the thick-billed murre, which is strongly associated with sea ice. Other threats include fisheries interactions, over-exploitation, contaminants, and oil spills, the latter becoming more important if climate change expands shipping and hydrocarbon development in the Arctic.
Seabirds – common eiders
Seabirds2Common eiders are important for traditional food and lifestyles, as well as being the basis of a commercial industry. The world population ranges between 1.5 and 3.0 million breeding pairs. Along with other eider species, common eiders have experienced substantial declines over several decades. Current trends vary but some populations in Alaska, Canada, and Greenland are recovering with improved harvest management. Disease outbreaks such as avian cholera can dramatically affect common eiders, while fishing by-catch in gillnets is a significant problem in some areas. Increasing oil and gas activities may put eider ducks at further risk in the future.
Arctic char
Arctic_charArctic char are widely distributed throughout the circumpolar north and are an important species culturally, socioeconomically, and scientifically. Populations of char in the Arctic are generally healthy in comparison to more southern populations. There are, however, many examples of stressed populations, especially near communities where over-fishing, sometimes combined with habitat change, has led to population collapses. The effects of climate change on Arctic char may be both positive and negative within different populations, and may impact the fish directly or indirectly through habitat and ecosystem changes.
Invasive species (human-induced)
Invasive_speciesAcross the globe, invasive species have caused extensive economic and ecological damage and are a significant factor in the endangerment and extinction of native species. As native species are lost so too are the potential cultural, subsistence, and other human uses of that biodiversity. Although biological invasions are less studied in the Arctic, invasive species have been reported in both aquatic and terrestrial environments. Arctic lands and waters have thus far remained largely intact and less invaded than more temperate environs, but are increasingly at risk of invasion. In terrestrial ecosystems, many invasive plants have been recorded along limited road systems and other altered habitats. There is less information on marine ecosystems but they are believed to be at increasing risk from shipping and offshore development activity. As climate change alters Arctic ecosystems and allows more human access and activity, the number of invasive species and the extent of their impacts in this region are likely to increase.
The Arctic Species Trend Index
ASTIThe Arctic Species Trend Index (ASTI) was developed to provide a pan-Arctic perspective on trends in Arctic vertebrates. Tracking this index will help reveal patterns in the response of Arctic wildlife to growing pressures and thereby facilitate the prediction of trends in Arctic ecosystems. A total of 965 populations of 306 species were used to generate the ASTI. Overall, the average population of Arctic species rose by 16% between 1970 and 2004, although this trend is not consistent across biomes, regions, or groups of species. The terrestrial index shows an overall decline of 10%, largely a reflection of declines (-28%) in terrestrial high Arctic populations such are caribou, lemmings, and the high Arctic brent goose. Declines in terrestrial high Arctic populations may be partly due to the northward movement of southern species in combination with increasing severe weather events in the high Arctic and changing tundra vegetation. Although both freshwater and marine indices show increases, the data behind the freshwater index is currently too sparse in terms of species and populations, while the marine index is not spatially robust.
Arctic genetic diversity
Arctic_geneticUnderstanding genetic variation in Arctic species is critical to their conservation and effective management in this time of rapid environmental change. Genetic analyses can be used for a variety of purposes, from determining the history of species dispersal and diversification to evaluating the conservation status of a species of concern. As the range and abundance of species declines, the genetic variability needed to respond to novel challenges will also be reduced. A significant increase in our efforts to build temporally-deep and spatially-extensive specimen archives is needed. These specimens will provide a baseline of environmental conditions and, when combined with mapping of genetic structure, will be crucial for both effective recovery efforts for declining species and for predicting species response in the face of climate change and other human impacts in the Arctic.