Land-based fauna on Svalbard
Svalbard has a rich bird and animal life. Over long periods of time, some species have adapted to the climate here, while others migrate between Svalbard and warmer climes. Most extreme is the Arctic tern, which commutes between Svalbard and the Antarctic.
Despite its location in the far North, the archipelago of Svalbard has a rich and diverse birdlife. Numerically, it is the seabirds that dominate, but the terrestrial ecosystem is also home to many species.
A large number of different bird species have been observed on Svalbard (212 as at 01.01.2015), but only 28 of them are considered to be habitual nesting birds. 13 species are considered to be sparse, irregular or probable nesters and a further 12 have been recorded as nesting on at least one occasion. The remaining species are sporadic guests. As climate change progresses, observations of new species are expected in its wake, either as vagrants or as nesting birds.
Among the terrestrial bird species, the Svalbard rock ptarmigan (Lagopus muta hyperborea) and the snow bunting (Plectrophenax nivalis) are probably the best known. The Svalbard rock ptarmigan is an indigenous sub-species of the ptarmigan and the only terrestrial bird that resides on Svalbard year-round. The snow bunting is a migratory bird, but, against that, is Svalbard's only passerine.
In summer, the terrestrial ecosystem gains a number of migratory species that nest in the tundra landscape. Common nesting species are the red-throated diver (Gavia stellata), the brent goose (Branta bernicla), the barnacle goose (Branta leucopsis), the pink-footed goose (Anser brachyrhynchus), the purple sandpiper (Calidris maritima), the European golden plover (Pluvialis apricaria), the dunlin (Calidris alpina), the grey phalarope (Phalaropus fulicarius), the ringed plover (Charadrius hiaticula), the sanderling (Calidris alba), the ruddy turnstone (Arenaria interpres), the red-necked phalarope (Phalaropus lobatus). Of these, the purple sandpiper is the commonest and most numerous species, the red-throated diver is spread over most of Svalbard, typically at smaller lakes and tarns, while the populations of barnacle goose and pink-footed goose have grown strongly in the last 30-40 years.
Many of Svalbard's birds are on the Norwegian Red List either because their populations are declining or they live as small, vulnerable populations at the extremes of their distribution ranges. This is the case for the waders (European golden plover, dunlin, red knot, red phalarope, sanderling, ringed plover and turnstone), long-tailed skua and brent goose.
The seabirds constitute an important link between the marine and terrestrial ecosystems, by fertilizing the areas within and around the bird cliffs. This creates a resource for nutrient-rich vegetation, which the terrestrial birds exploit.
The terrestrial bird species are affected by various environmental factors, of which climate change is the most important. The Svalbard rock ptarmigan which lives year round on Svalbard is affected negatively by mild rainy winters with iced-covered grazing which prevents access to grazing plants and limits food availability. An earlier start to spring can cause changes in nesting biology and a mismatch between the time of hatching and the nutritional content and presence of important grazing plants for the chicks, which are specialists. Similarly, increasing goose populations may cause more competition with the indigenous herbivores, ptarmigan and reindeer, for important grazing plants.
The Svalbard rock ptarmigan and pink-footed goose are harvested through annual small-game hunting by residents, visitors (only ptarmigan) and a few professional hunters. The Svalbard rock ptarmigan is the most popular and is harvested in the largest numbers, whereas far fewer pink-footed geese are shot. The population of pink-footed geese has increased rapidly as a result of a combination of land-use changes in the overwintering areas and climate change. A reduction of the population is desirable due to the strong influence that the pink-footed goose can have on processes and functions in the ecosystem, through, for example, pasture damage and competition for important grazing plants with the indigenous species.
The terrestrial bird species are vulnerable to human traffic to varying degrees. The most vulnerable period is the nesting time before hatching, and species which nest in concentrations or colonies are most vulnerable. This is the case, for example, for the pink-footed goose and the barnacle goose. Here, human foot traffic and low-flying helicopters may contribute to lower reproduction. The pink-footed goose has proved to be most sensitive to disturbances. The goose species are also vulnerable during moulting, in July-August
The Svalbard rock ptarmigan has been included in MOSJ (Environmental Monitoring of Svalbard and Jan Mayen) since the annual monitoring began in 2000. It is proposed to include the pink-footed goose and barnacle goose in the scheme. The Svalbard rock ptarmigan and pink-footed goose are included in the COAT (Climate-Ecological Observatory for Arctic Tundra) scheme. It is considered important to register all three goose species and the ptarmigan in the Circumpolar Biodiversity Monitoring Program (CBMP).
Within Svalbard's terrestrial ecosystem, only three species of mammal overwinter. The fauna consists of two herbivores: the indigenous Svalbard reindeer (Rangifer tarandus platyrhynchus) and a local, introduced population of the sibling vole (Microtus levis) and the predator and scavenger, the Arctic fox (Vulpes lagopus).
The mammals in the terrestrial ecosystem are vulnerable to and affected by climate change. Earlier snow melt in spring, warmer summers, longer growing season, milder winters with more precipitation and more frequent rainy periods will affect the food supply, living environment and the species' demographic rates (reproduction and mortality). The effect of icing episodes leading to increased mortality and lower reproduction in Svalbard reindeer and southern voles is well-documented. The Arctic fox is affected indirectly by tundra icing with a negative response in growth potential, delayed by a year, resulting from ice-covered reindeer pasture. The greatly increasing stocks of geese nesting on Svalbard may be a positive factor for the Arctic fox due to an increase in access to prey in the form of adult birds, chicks and eggs. The Arctic fox also depends on access to sea ice in the fjords in late winter during the birthing period of ringed seals in order to obtain food. A lack of fjord ice in the spring months may cause this food source to disappear. If the sea ice in the Arctic Ocean disappears, the Arctic fox population in Svalbard will be isolated, since they use the sea ice as a platform for moving between the Arctic land masses.
Both the Arctic fox and Svalbard reindeer are harvested locally, but the present catch is not considered to affect the stocks notably. A restricted hunt of the reindeer for residents and a few professional hunters has been allowed on Svalbard since 1983. Between 117 and 235 reindeer are culled annually, in addition to a commercial quota. Residents catch Arctic fox in 25 hunting areas on Nordenskiöld Land and at Kongsfjorden in addition to a few professional hunters. Between 35 and 160 Arctic fox are trapped annually. Population monitoring data shows no clear indications of any consistent decline in population size despite the Arctic fox having been hunted over a long period. Explanations for this are that trapping occurs in restricted areas and that the population's growth potential and/or immigration inhibits a reduction in its size.
Human traffic may affect both species, perhaps particularly in late winter after a hard winter, if there is a lot of snowmobile traffic in key grazing areas (Svalbard reindeer), during calving periods for Svalbard reindeer and near den locations (Arctic fox). There is data from provocation studies of foot and snowmobile traffic for Svalbard reindeer. These say something about the impact of traffic on individuals but its significance for the population's survival and reproduction is unknown. In areas of large and regular snowmobile traffic, much points to the ability of Svalbard reindeer to become habituated to such disturbances.
Among the terrestrial species, it is only the Arctic fox that is subject to high levels of environmental toxins since it also feeds from the marine food chain. Otherwise, the terrestrial mammals are not so exposed to environmental toxins as marine species. The levels of toxins in Arctic foxes may be affected by climate change, since access to different prey species is strongly influenced by climate and the different prey have different levels of environmental toxins. There are reasons to believe that these high toxin levels may have negative effects on the foxes' health.
The incidence of disease and parasites such as Echinococcus multilocularis and rabies in Arctic foxes is being investigated and is significant for animal health and the transmission of disease to other wildlife (reindeer) and human health (zoonosis).
The Svalbard reindeer and Arctic fox are included in MOSJ (Environmental Monitoring of Svalbard and Jan Mayen). At present, there is no monitoring of southern vole or the incidence of the Echinococcus multilocularis tapeworm. Annual reports are made of reindeer population numbers for central areas of Nordenskiöld Land (1979─ ) and on Brøggerhalvøya (1978─ ) and the proportion of dens with pups in Adventdalen/Sassendalen (1997─) and on Brøggerhalvøya (1993─). The numbers of culled reindeer and trapped Arctic foxes are also reported. Reindeer and Arctic fox are also key species for monitoring in the Circumpolar Biodiversity Monitoring Program (CBMP) and in the Climate-Ecological Observatory for Arctic Tundra (COAT).