Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

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Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

The Barents Sea has been monitored and investigated for more than 50 years in a collaborative effort between Norway and Russia.This has provided an extensive knowledge base for this sea area (Sakshaug et al., 2009; Jakobsen and Ozhigin, 2011). 6.2.2.1 Impacts of climate variability and change Large climate and ecological variability is a key feature of the Barents Sea marine ecosystem. Climate variability is expressed on different time scales includingmulti-decadal and interannual fluctuations. The observed responses to climate variability of ecosystem components including plankton, fish, benthos, birds andmarine mammals form a basis of reference for assessing the likely impacts of future climate change.With the warming over recent decades there has been a general increase in the overall abundance and spread of boreal species, and a decline and retreat of Arctic species. This ‘borealization’ with a northward shift in distribution is likely to continue under the warming projected for the next 50 years (Fossheim et al., 2015). The cold waters of theArctic Ocean are particularly vulnerable to the rapid and progressive process of ocean acidification (AMAP, 2014b and references therein). The pH of surface waters in the Norwegian Sea has decreased significantly over the past 30 years (Skjelvan et al., 2014). While not uniform across the area and demonstrating seasonal and interannual variability, ocean acidification has direct and indirect effects on Arctic marine life (Orr et al., 2005; AMAP, 2014b). While impacts vary significantly for different organisms (Secretariat of the Convention on Biological Diversity, 2014), they are likely to lead to significant changes in marine ecosystems, such as changes in species composition, leading to potential impacts on Arctic fisheries and economic and social impacts on livelihoods (AMAP, 2014b). Continued decline in winter sea ice in the Barents Sea (see Chapter 4) is expected to lead to increased primary production by phytoplankton (Ellingsen et al., 2008; Skaret et al., 2014) and decreased primary production by ice algae. But because the contribution of ice algae to the total primary production in the Barents Sea has been low in recent years (<5%) despite extensive ice cover (Hegseth, 1998;Wassmann et al., 2006; von Quillfeldt et al., 2009), the effect on total production is low and compensated for by increased production by phytoplankton. However, less ice algae as well as reduced occurrence of other ice biota represents a major qualitative change in the ecosystem in the northern Barents Sea. Increased warming and little or no ice in the Barents Sea by 2070 (see Chapter 4), is expected to result in an expansion of boreal zooplankton and a reduction in Arctic zooplankton. With warming there is an extension of the reproductive habitat for the dominant copepod Calanus finmarchicus in the southern and central Barents Sea, and increased production due to a greater role for a second generation of the copepods in the warmer AtlanticWater (Melle and Skjoldal, 1998; Skaret et al., 2014). However, this species is expected to continue to be expatriated and not able to occupy the still cold waters of the northern Barents Sea for its breeding habitat. For the closely related Arctic species C. glacialis , the impact of warming and little or no sea ice is unclear.It is possible that the overall effect of warming and less ice may be favorable for C. glacialis , allowing

decomposition, nutrient cycling, and vegetation productivity, which will in turn increase greenhouse gas emissions and carbon uptake. Invertebrate activity will also increase, which is important because invertebrates play a crucial role in the pollination of many Arctic plants and are the major food source for many breeding birds and freshwater fish species. An increase in invertebrate activity and diversity may further promote dispersal of vegetation and increase populations of both Arctic and invasive species of birds and fish. Importantly for reindeer herding, the seasonal pattern of occurrence and abundance of biting flies and mosquitos is increasing in some places (CAFF, 2013a,b). Similar to today, harvest, disturbance, and habitat loss outside the Arctic are expected to influence the population trends of many Arctic (including migratory) birds in the future. The consequences of changing climatic and vegetation conditions on Barents area bird populations are difficult to project, but are expected to be a gradual and continuous process, rather than a ‘sudden’ tipping point change (Lenton, 2012). Changing bird populationsmay have consequences for society via their impacts on vegetation (through grazing) and on eutrophication of lakes and as hunting species. Some grouse species, important for hunting and seed dispersal,may be affected more immediately by disappearing snowbeds (which provide cover) and changes in insect abundance (Arctic Council, 2013 and references therein). For overwintering small rodents and for reindeer, decreasing snow cover may be critical as snowbeds provide cover (frommosquitos) and temperature relief in summer, and their gradual melt through the season improves pasture quality for reindeer (Lenton, 2012). Thus, decline in snow cover may decrease pasture quality and have consequences for reindeer health and reproduction (Callaghan et al., 2011). Further effects of changes in snow abundance and quality as well as trends in industrial development and fragmentation are discussed in Section 6.3.1.1 and Chapter 7 and in other sections on reindeer herding.Otherwise, climate change and a continued northward expansion of the boreal forest may allow moose ( Alces alces ) (an important hunting species) and southern generalist species to spread further north (Elmhagen et al., 2015). The ultimate impact of climate change,increasingly pronounced interannual variability and increasing impacts of human activities depend on the complex interactions between the different drivers and species (Arbo et al., 2012).The combined changes will have consequences for society especially through their effects on ecosystem services (Jansson et al., 2015 and Chapter 2). Main research needs include more monitoring to better understand species interactions, biome shifts and future land-use changes (including forestry, farming and recreation), as well as better understanding of ecosystem service use in the Barents area, including Russia. 6.2.2 Marine and coastal ecosystems The Barents Sea is a flow-through system with Atlantic Water entering from the Norwegian Sea in the southwest and leaving between Novaya Zemlya and Franz Josef Land in the northeast (see Chapter 2). This sets the stage for the Barents Sea being a biogeographical transition zone between a warmer boreal region in the southern part and an Arctic region in the north.