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

9

Chapter 2 · Status of the natural and human environments

(CAFF, 2013), in terms of species density, include nematodes (Nematoda), springtails (Collembola), non-biting midges (Chironomidae),mosquitoes (Culicidae), flies (Diptera),mites (Arachnida), moths (Lepidoptera), tardigrades (Tardigrada) and small earthworms (Enchytraeidae). The length of the growing season (seasonal spread of photosynthetic activity) in the Barents area has increased over the past 30 years, and plant flowering has advanced by up to 20 days during a single decade in some areas (Xu et al., 2013). Primary productivity and vascular plant biomass have increased rapidly in terrestrial communities – particularly in terms of increased growth and expansion of tall shrubs.However, plants in the lowest vegetation layers, such as mosses and lichens, are declining in terms of abundance (CAFF, 2013). See Chapter 6 for further discussion. Glaciers Glaciers constitute about 4% of the area and are mainly present on Novaya Zemlya and the islands of Svalbard and Franz Josef Land, meaning they are well within the HighArctic as defined by the Arctic Council working group Conservation of Arctic Flora and Fauna (CAFF). Climatic conditions are harsh, with an average July temperature of 4–6°C and an average annual precipitation of less than 200 mm to just above 400 mm. The glaciers are classed into different types based on morphology. Most dominant by area are the large continuous ice masses – plateau glaciers – that are subdivided into individual ice streams by mountain ridges and nunataks (isolated peaks of rock projecting up through the ice). The presence of small animals during summer has probably been noted by most people walking on glaciers in summer. However, recognizing the existence of glacial ecosystems exploiting habitats such as wet snow, cryoconite holes, streams, ponds and moraines in the ice masses is relatively new (De Smet and van Rompu, 1994; Säwström et al., 2002). According to Hodson et al. (2008) there are two key glacial ecosystems, one inhabiting the glacier surface (the supraglacial system) and one at the ice- bed interface (the subglacial system). Life in the supraglacial ecosystem, with its snowpack, supraglacial streams and melt pools is characterized by bacteria, algae, phytoflagellates, fungi, viruses and occasional rotifers, tardigrades, and diatoms. The basal ice/till mixtures and subglacial lakes of the subglacial system are dominated by bacteria and probably viruses (Säwström et al., 2007). Despite differences between continental glaciers (decreasing) and oceanic glaciers (increasing), the overall trend is a major decline in glacier volume and area throughout the Barents area. See Chapter 4 for further discussion of changes in glaciers. Freshwater ecosystems The Barents area contains abundant and wide-ranging freshwater ecosystems, including lakes, ponds, rivers and streams and a complex array of wetlands and deltas. These contain habitats of varying ecological complexity that support a range of permanent and transitory species adapted to life in a highly variable and extreme environment (Vincent and Laybourn-Parry, 2008). They also serve as important 2.2.1.3 Glaciers, freshwater ecosystems, wetlands

temperatures down to around -30°C.Mean annual precipitation ranges between 150 and 250mm inmainland areas (Figure 2.2), but is lower in High-Arctic desert areas such as Svalbard and Novaya Zemlya.However, due to low rates of evaporationmost tundra areas often appear wet. Permafrost prevents the shallow lakes and bogs from draining and these wetland areas are very important for insects as well as for providing food and water for many birds. In contrast, alpine tundra lacks permafrost and so has better-drained soil. Tundra vegetation is dominated by perennial dwarf shrubs, sedges,grasses,bryophytes and lichens (Chernov andMatveyeva, 1997; Olson et al. 2001; Kobyakov and Jakovlev, 2013). Freeze- thaw activity,a thin active layer (in areas of permafrost),and soil slippage during the summer thaw contribute to strong controls on vegetation patterns and create a mosaic of microhabitats and plant communities. So even though many of the same plant species (at least for alpine tundra) occur in the taiga, the vegetation cover in the tundra looks different as it is often less continuous and the vascular plant species are shorter. Animal species have evolved strategies to withstand the harsh environment (CAFF, 2013).Among resident mammals and birds, such as the Arctic hare ( Lepus arcticus ), Arctic fox ( Vulpes lagopus ) and ptarmigan ( Lagopus muta ), morphological adaptations expressed as a thick insulating cover of feathers or fur, and pelage and plumage that turn white in winter and brown in summer are among the adaptive suite of characters common to the terrestrial community. In addition, physiological adaptations such as the ability to accumulate thick deposits of fat during the short growing season, which then act as insulation and a store of energy for use during winter, are important characteristics of the animals of the northern Barents area. Other common species include lemming ( Lemmus spp.) and reindeer ( Rangifer tarandus platyrhynchus ). For the High Arctic in particular, the resident terrestrial fauna of birds and mammals (Ims et al., 2014) has low species diversity, and this is especially true for Svalbard and Franz Josef Land in the northern reaches of the Barents area. Only the reindeer, Svalbard ptarmigan ( Lagopus mutus hyperboreus ) and Arctic fox reside on land year round. This is not too surprising given that over 60% of the land in Svalbard and 85% of the land in Franz Josef Land is glaciated. The reindeer in Svalbard is a unique subspecies compared to the mainland or to Greenland; its relationship to animals in Franz Josef Land is not known. The ptarmigan in Svalbard is likely to be the same subspecies as that in Franz Josef Land, based on morphology, so both terrestrial grazers have experienced island-endism phenomena. The Arctic fox travels widely across the sea ice between land masses and so populations are broadly spread and genetically open to other areas. Migratory species such as waterfowl, shorebirds and domesticated reindeer avoid the harsh winter by moving south into the boreal forest or even further south at the end of the growing season. In spring, they return to the tundra to breed and feed. Many invertebrate species are endemic to the Arctic. Due to their small size and ability to move they can utilize the variety of microhabitats in the landscape, interacting with climatic differences and the contrasting biotic environment (Coulson, 2000). Common groups of invertebrate tundra species