Арктика меняется

Hans Meltofte, Henry Huntington and Tom Barry

Figure 1. Map of the top of the northern hemisphere with the high and low Arctic zones delineated according to the Circumpolar Arctic Vegetation Map (CAVM Team 2003), together with a tentative demarcation of the sub-Arctic. Lines indicating similar marine zones are sketched (Source:CAVM Team 2003)

The Arctic is made up of the world’s smallest ocean surrounded by a relatively narrow fringe of island and continental tundra north of the tree line (Fig. 1). Extreme seasonality and permafrost determine the hydrology, biodiversity and general features of the Arctic’s terrestrial ecosystems. Similarly, seasonal and permanent sea ice is the defining feature of the Arctic’s marine ecosystems.

The Arctic holds some of the most extreme habitats on Earth, with species and peoples that have adapted through biological and cultural evolution to its unique conditions. A homeland to some, and a harsh if not hostile environment to others, the Arctic is home to iconic animals such as polar bears, narwhal, caribou/reindeer, muskoxen, Arctic foxes, ivory gulls and snowy owls, as well as numerous microbes and invertebrates capable of living in extreme cold. The Arctic also holds large intact landscapes and seascapes with little or no obvious sign of direct degradation from human activity. In addition to flora and fauna, the Arctic is known for the knowledge and ingenuity of Arctic peoples, who thanks to great adaptability and ingenuity have thrived amid ice, snow and winter darkness.

With these features in mind, the purpose of the recently published Arctic Biodiversity Assessment (ABA), is to Synthesize and assess the status and trends of biological diversity in the Arctic … as a major contribution to international conventions and agreements in regard to biodiversity conservation; providing policymakers with comprehensive information on the status and trends of Arctic biodiversity. The intent is to provide a much-needed description of the current state and recent trends in the Arctic’s ecosystems and biodiversity, create a baseline for use in global and regional assessments of Arctic biodiversity and a basis to inform and guide future Arctic Council work. The ABA provides up-to-date knowledge, identifies gaps in the data record, describes key mechanisms driving change and presents suggestions for measures to secure Arctic biodiversity.

The ABA comes in three publications: the Full Scientific Report, a stand-alone Synthesis and a Summary report for policy makers. The assessment focuses on the species and ecosystems characteristic of the Arctic region, including ecosystem services and indigenous languages, and draws together information from a variety of sources to discuss the cumulative changes occurring as a result of multiple factors. The ABA identifies current status together with historical trends in abundance and distribution where available, and includes projections of future change informed by scientific literature. It draws on a vast number of scientific publications, supplemented by ‘eye witness’ observations from indigenous peoples. The ABA has been through comprehensive peer review to ensure the highest standard of analysis and unbiased interpretation. The results are a benchmark against which to help measure and understand the significance of future change, without which the scope and gravity of future changes will be less clearly identifiable, undermining our ability to reduce harm.

Today, Arctic biodiversity is changing, perhaps irreversibly. Change in the Arctic comes in many forms and from a variety of sources. Several of these stressors have been the subject of intense research and assessments documenting the effects and impacts of human activity regionally and globally, and seeking ways to conserve the biological and cultural wealth of the Arctic in the face of considerable pressures to develop its resources. These assessments have focused primarily on effects and impacts from a range of present and future stressors, such as global warming (ACIA 2005, AMAP 2009a, AMAP 2011a), oil and gas activities (AMAP 2009b), social change (AHDR 2004), marine shipping (AMSA 2009) and environmental contaminants (AMAP 1998, 2004, 2010, 2011b). The ABA, in contrast, looks not at the stressors but at the biodiversity being stressed.

A key challenge for conservation in the Arctic is to shorten the gap between data collection and policy response. The Arctic Council has recognized this challenge and in recent years, through the working group for Conservation of Flora and Fauna (CAFF), has been developing a solution. This approach has focused on not just developing a classical assessment but also addressing the collection, processing and analysis of data on a continuous basis. The ABA is not just a one-time, static assessment, but rather provides a baseline of current knowledge, closely linked to the development of CAFF’s Circumpolar Biodiversity Monitoring Program (CBMP) as the engine for ongoing work.

Conservation action based on the findings of the ABA will not happen in a vacuum. All Arctic Council states have made commitments that, directly or indirectly, help protect biodiversity and ecosystems through a number of conventions as well as bi- and multilateral agreements, including the Convention on Biological Diversity (CBD), United Nations (UN) Framework Convention on Climate Change (UNFCCC), Convention to Combat Desertification (CCD), Bonn Convention (CMS), Ramsar Convention on Wetlands of International Importance, UN Educational, Scientific and Cultural Organization (UNESCO), World Heritage Convention (WHC) and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Each Arctic Council country is a party to at least one of these conventions and has, thereby, made commitments that have the intention toprotect and restore biodiversity.

Furthermore, based on the ABA, the Arctic Council agreed on and approved a set of key findings and recommendations at the meeting of ministers in Kiruna, Sweden in May 2013 (CAFF 2013).

Main findings of the ABA

Arctic biodiversity – the multitude of species and ecosystems in the land north of the tree line together with the Arctic Ocean and adjacent seas – is an irreplaceable cultural, aesthetic, scientific, ecological, economic and spiritual asset. For Arctic peoples, biodiversity has been the very basis for their ways of life through millennia, and is still a vital part of their material and spiritual existence. Arctic fisheries and tourism are also of particularly high value for the rest of the world, and so are the millions of Arctic birds and mammals migrating to virtually all parts of the globe during winter.

The Arctic is home to more than 21,000 species of often highly cold-adapted mammals, birds, fish, invertebrates, plants and fungi (including lichens) – together with large numbers of undescribed endoparasites and microbes. Arctic biodiversity includes charismatic and iconic species together with marine and terrestrial ecosystems such as vast areas of lowland tundra, wetlands, mountains, extensive shallow ocean shelves, millennia-old ice shelves and huge seabird cliffs.

The functional significance of different groups of organisms in maintaining the integrity, structure, services and health of Arctic ecosystems, however, is generally greatest among those we understand least. Microorganisms are key elements of Arctic ecosystems, yet they have been little studied.

Anthropogenically driven climate change is by far the most serious threat to biodiversity in the Arctic, and there is an immediate need to implement actions to reduce this stressor. Due to a range of feedback mechanisms, the 2 °C upper limit of human-induced warming, chosen by world leaders, is projected to result in an air temperature increase of between 2.8 and 7.8 °C in the Arctic, likely resulting in severe disruptions to Arctic biodiversity.

Figure 2. Trends in terrestrial June snow cover 1967-2012 based on averages for the North American and Eurasian continents, virtually all of it in the Arctic. Values are standardized anomalies with respect to the 1988-2007 mean. Solid lines are five-year running means. The combined influence of the timing of snow melt and the length of the growing season is of major importance for the functioning and feedback dynamics of Arctic Ecosystems.( Source: adapted from Derksen & Brown, Spring snow cover extent reductions in the 2008-2012 period exceeding climate model projections. Geophysical Research Letters, 2012)

Climate change is the most likely explanation for shifts already visible in several parts of the Arctic, as documented by both scientists and Arctic residents. These include northward range expansions of many species and changes in ecosystems likely resulting from habitat warming and/or drying of the substrate associated with warming and earlier snow melt (Fig. 2), together with development of new oceanic current patterns. 

Future global warming will result in further northward shifts in the distribution of a great many species. This will include boreal species and ecosystems encroaching on areas currently characterized as the low Arctic, and low Arctic species and ecosystems encroaching on areas currently characterized as the high Arctic.

Northward movement of boreal species may increase the number of species found in the Arctic, but this does not represent a net gain in global biodiversity. The additions will primarily be species that are already common in southern habitats, some of which may outcompete or displace unique assemblages of Arctic species with the risk of severe range reductions and possible extinctions.

Terrestrial habitats in the Arctic are bounded to the north by marine ecosystems. Therefore, northward ecosystem shifts are expected to reduce the overall geographic extent of terrestrial Arctic habitats – in particular for high Arctic habitats. Arctic terrestrial ecosystems may disappear in many places, or only survive in alpine or island ‘refugia’.

Arctic freshwater ecosystems are undergoing rapid change in response to the influence of both environmental and anthropogenic stressors. The distribution and number of lakes, ponds, wetlands and riverine networks are being altered with significant implications to the structure, function and diversity of associated biological communities.

Figure 3. The loss in summer extent of Arctic Ocean sea ice has occurred much faster than the initial projections had anticipated, so that the total ice cover at the summer minimum reached an all time low in September 2012 with only half the extend as compared with the 1979-2000 average. Similarly, the loss in monthly averaged Arctic Ocean ice volume for August 2013 was 76% lower than the maximum in 1979 (Polar Science Center 2013). (Source: modified from Stroeve et al.". Arctic sea ice decline: Faster than forecast" 2007)

In the marine Arctic, climate-induced effects on species and ecosystems, associated with a decrease in sea ice extent and duration (Fig. 3), are already being observed. Of key concern is the rapid loss of multi-year ice in the central Arctic basin and changes in sea ice dynamics on the extensive Arctic shelves, which affect the biodiversity and productivity of marine ecosystems.

A secondary effect of increased CO₂ in the atmosphere is ocean acidification resulting from increased dissolved CO₂. Since the solubility of CO₂ is higher in cold than warm waters, Arctic marine ecosystems are especially prone to acidification, and there are already signs of such changes in the Arctic Ocean. This is an important threat to calcareous organisms, and thereby may have cascading impacts on marine ecosystems including potential impacts on biodiversity and fisheries.

Until the second half of the 20^th century, overharvest was the primary threat to a number of Arctic mammals, birds and fishes. A wide variety of conservation and management actions have helped alleviate this pressure in many areas to such an extent that many populations are recovering, although pressures on others persist.

Since the middle of the 20^th century, a variety of contaminants have bioaccumulated in several Arctic predator species to levels that threaten the health and fecundity of both animals and humans. However, due to concerted global action to reduce the release of contaminants, there are, as yet, few demonstrated effects on Arctic species at the population level. Lack of data may mask such impacts, however. New contaminants, and changing fluxes of others, continue to be introduced to Arctic ecosystems and related food webs with unknown ecosystem effects.

Arctic habitats are among the least anthropologically disturbed on Earth, and huge tracts of almost pristine tundra, mountain, freshwater and marine habitats still exist. While climate change is the most geographically extensive and potentially harmful anthropogenic impacts at present, regionally ocean bottom trawling, non-renewable resource development and other forms of intensive land use pose serious challenges to Arctic biodiversity.

Pollution from oil spills at sites of oil and gas development and from oil transport is a serious local threat particularly in coastal and marine ecosystems. A major oil spill in ice-filled waters would be disastrous to marine mammals, birds and other biota, because containing and cleaning up oil spills in broken ice is very difficult, particularly under problematic weather, light and ice conditions.

Many Arctic species spend much of the year outside the Arctic; e.g., Arctic waterbirds are highly dependent on a network of staging and wintering areas in wetlands in many parts of the world. These habitats are experiencing severe development pressure and in some cases overharvest, particularly in East Asia, but also in other parts of the world.

At present, few human-introduced alien species, including pathogens and disease vectors, are spreading unchecked and putting Arctic species under pressure. However, the pathways by which invasive species spread, such as shipping and resource development corridors, are rapidly expanding and may dramatically increase the rate of introduction. Many potentially disruptive alien species are also found in sub-Arctic regions and will probably spread northwards along with other species in a warming climate.

There is an enormous deficit in our knowledge of species richness in many groups of organisms, and monitoring in the Arctic is lagging far behind that in other regions of the world. Even for the better-studied Arctic species and ecosystems we have insufficient data on trends in distribution, abundance and phenology and too few natural history specimens for retrospective and baseline analyses. In addition, the functioning of Arctic ecosystems is insufficiently understood making it difficult to implement ecosystem-based monitoring and management. Hence, there is a critical lack of essential data and scientific understanding necessary to improve the planning and implementation of biodiversity conservation or monitoring strategies in the Arctic.

The multitude of changes in Arctic biodiversity – driven by climate and other anthropogenic stressors – will have profound effects on the living conditions of peoples in the Arctic, including the diversity of indigenous languages, cultures and the range of services that humans derive from Arctic biodiversity. While ecosystem changes already underway may provide new opportunities, they will also lead to loss and, at a minimum, require considerable adaptation and adjustment.

Suggested conservation and research priorities

Taken together, the most serious pressure on Arctic biodiversity in the past was overharvest, whereas the most serious present and future pressure is climate change. Most overharvest problems are relatively easy to address and many have been alleviated, while others such as heavily depleted seabird populations in Greenland remain to be solved. An effective response to climate change, on the other hand, seems at the moment to be outside the capacity of human societies. This gives gloomy prospects for ecosystems and species in the Arctic and elsewhere.

The erosion of global biodiversity is not the only global crisis of our time. It has been argued that changes in climate, biodiversity, infectious diseases, energy supplies, food, freshwater, human population and the global financial system are part of one contemporary global challenge, and that they need to be addressed as such (Steffen et al. 2011). If this is not done in an integrated and sustainable way, efforts to address one challenge may very well worsen one or more of the others. Also, global markets seek the exploitation of Arctic resources, resulting in greater interconnections between the Arctic and the rest of the world.

To safeguard Arctic biodiversity and the services we receive from it, three spatial levels of stressors must be addressed: (1) global and circumpolar stressors like climate change and long-range transport of contaminants by air and sea water, (2) regional stressors like overexploitation, expanding boreal and invasive alien species, and (3) more ‘localized’ stressors like mineral extraction, oil development and ship accidents. Here, the 35 lead authors of the ABA provide a set of suggested priorities for actions defined according to these three geographical scales.

The alleviation of global and circumpolar stressors with effects on species and ecosystems generally requires international cooperation for effective management.[1]

•             Conserving the unique Arctic biome will require all possible efforts to curb human-induced global warming. 
•    Global and regional actions to reduce both legacy and new environmental contaminants entering Arctic ecosystems should continue and, where necessary, intensify under existing international conventions.
• Effective conservation of Arctic biodiversity needs to be global in scope and requires significant international cooperation to succeed. Any action to solve one global challenge should take others into account so that measures to solve one stressor do not worsen others.

Since many fish, birds and mammals move between different regional and national jurisdictions, management can benefit from regional cooperation.

•        To maximize the resilience of Arctic ecosystems, effective protection of large representative tracts of habitat, including hotspots for unique Arctic biodiversity and northern ‘refugia’ areas, is of paramount importance. This includes Arctic islands together with mountainous areas and multi-year sea ice refuges, where unique marine Arctic biodiversity has the best chance of surviving climate change.
• A major oil spill in ice filled Arctic waters would be detrimental to biodiversity and very difficult to clean up, particularly under problematic weather, light and ice conditions. However, if oil development is undertaken, a precautionary approach adhering to regulations and guidelines specific to the Arctic and based on the best available science would reduce risks. This approach should include avoiding development activities in the most sensitive areas.
•  Focused harvest management of fish, birds and mammals is needed on those species and populations that have experienced major declines for which harvest is one of the causal factors.
• To protect staging and wintering wetland areas for Arctic waterbird migrants from both habitat loss and overharvest, concerted international efforts should be conducted to conserve a network of key areas and address overharvest. This is especially critical in the East Asian flyway.
• To effectively protect Arctic native species and ecosystems from devastating effects of invasive alien species, appropriate efforts are needed to prevent their establishment in the Arctic. Early detection and preventative actions should focus on areas of human activity and disturbance.

Although many aspects of local stressors can be managed by national or local authorities, bilateral or international cooperation on common standards may be needed in some cases and can be beneficial in most.

·    To protect Arctic biodiversity from severe impacts from local development and industrial activity, biodiversity conservation needs to be a cornerstone of natural resource management and land and marine planning.

·   Improved monitoring and research is needed to survey, map, monitor and understand Arctic biodiversity including integrated, repeated data collection following recommended standardized protocols and priorities, and involving Arctic citizens in the survey and monitoring, if we are to move ahead with science-informed decisions in the Arctic. Support for national and international coordinated efforts such as the CBMP and the BAR Code of Life is important to fill critical data gaps on population abundance and trends for many Arctic terrestrial and marine species as well as on changes in the functioning and services of Arctic ecosystems.

In order to effectively respond to these suggested priorities, international cooperation and direct action at the national level are required. Many such efforts are already underway, and the Arctic countries possess strong legal frameworks that can form the basis for effective conservation of Arctic biodiversity. Nevertheless, such agreements and initiatives are of little use if not backed up by secure long-term funding, enforcement and popular support.

The ABA has succeeded in identifying what needs to be done. Now comes the harder step of actually doing it. At the Arctic Council Ministerial in May 2013 the Foreign Ministers of the eight Arctic states instructed the Senior Arctic Officials of the Arctic Council that a plan to support and implement the ABA recommendations be developed. This implementation plan is scheduled for release in April 2014.

To build upon the work of the ABA, CAFF is organizing the first Arctic Biodiversity Congress in Trondheim, Norway on November 25-27, 2014.  The Congress will promote the conservation and sustainable use of Arctic biodiversity through dialogue among scientists, policy-makers, government officials, industry, civil society and indigenous peoples.

Hans Meltofte, Department of Bioscience, Aarhus University, Denmark

Henry Huntington, Huntington Consulting, Alaska, USA 

Tom Barry, Conseration of Arctic Flora and Fauna International Secretariat, Iceland