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

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Chapter 6 · Impact analysis and consequences of change

term (Bhatt et al., 2013), long-term projected changes include earlier spring greening and increased biomass and primary production (Swann et al., 2010). The current average browning trend of the tundra in Eurasia, indicating a long-term decrease in growing season, may be attributed to permafrost degradation and subsequent hydrological changes (Jorgenson et al., 2001; Frost and Epstein, 2014) and also to decreasing summer air temperatures (Bhatt et al., 2013). As vegetation and climate continue to change, browning may turn to a greening in some areas, depending on the hydrological (drying) effects of deciduous vegetation (Swann et al., 2010). Climate and vegetation changes may lead to more pest outbreaks, which in recent years have led to historically low vegetation productivity in the European North (Epstein et al., 2014). Climate induced vegetation changes may also increase potential for carbon sequestration (Chapter 4) but this effect may be masked by changes in albedo due to vegetation change (Swann et al., 2010). Overall, the potential consequences of these changes in climate, hydrology and vegetation, especially for the forestry sector, are serious and potentially rapid.These consequences are discussed further in Sections 6.3.1.3, 6.4.3 and Chapter 9. invertebrates, birds and mammals Many elements across the hydrological and social-ecological systems are interconnected. Fluxes and connections vary in strength through the seasons,andmay change completely as the climate changes,and as impacts associatedwith human activities and the presence of invasive species increase (Figure 6.1). Continued warming and increasing soil moisture will increase microorganism activity in the near and far term, increasing 6.2.1.2 Impacts on microorganisms,

large, the surrounding vegetation, and the animals depending on this (Post et al., 2009), as well as for livelihoods. See Section 6.3.1.5 for discussion on the impacts of climate change on freshwater fisheries. Direct climate- and cryospheric changes, the related indirect changes in hydrology, and grazing pressure are expected to have the greatest impacts on vegetation in the Barents area, although land-use change may become almost as important in the boreal biome (Elmhagen et al., 2015). The formation and draining of lakesmay also cause large shifts in vegetation and species balance with consequences for pastures and livelihoods.Such changes in hydrology and as a consequence vegetationmay take place over very short time scales,fromas little as three to five years to ten or more years.One example is the shift from tundra to boreal plant vegetation over a period of ten years in an alpine area of northern Swedish Lapland. This shift has had major consequences for grazing reindeer ( Rangifer tarandus ) as the grazing-important cotton grass ( Eriophorum vaginatum ) disappeared in favor of non-grazing important lingonberry ( Vaccinium vitis-idaea ) (Molau, 2010). Section 6.3.1.1 and Chapters 7 and 9 discuss the consequences of changes in temperature and precipitation for pastures and reindeer husbandry. Projections of vegetation change for the Barents area indicate gradual extensions northward and upward inmountain areas of bothpine- anddeciduous trees over the next 100 years (Wolf et al., 2007; Post et al.,2009),as temperatures and soil moisture increase especially during the first half of the century (Roderfeld et al., 2008). Open ground vegetation will largely disappear and be replaced by shrubs,whichwill decrease in extent and be gradually replaced by taller vegetation (Arctic Council, 2013). Trampling and grazing by reindeer and migrating bird populations can in some places affect vegetation composition and limit forest expansion (Ims et al., 2013), with consequences for hydrology. While growing season durationmay decrease due to hydrological changes and decreasing summer air temperatures in the short

January

December

Seasonal snow and vegetation changes

Climate

Human

Carnivores/predators

Carbon dioxide Methane

Water

Invasive species pests and diseases

Migratory species

Herbivores/prey

Glaciers

Forest

Vegetation

Ice

Snow

Lakes

Minerals, oil, gas

Permafrost

Organic material

Microorganisms

NUTRIENTS

Run-off and groundwater

Hydrological system

Greenhouse gases and nutrient fluxes

Social-ecological system

Figure 6.1 Important elements in the Arctic terrestrial and freshwater ecosystems (Bob van Oort, Cicero).