Where do you find them?
Invertebrates on Svalbard can be found just about anywhere, flying, under rocks, in the soil, crawling on the vegetation, in the streams and ponds, even on the surface of glaciers. However, they are more common where there is some soil and vegetation and also on the warmer west coast. As they are generally small they are often not obvious and some effort is required to observe them. Nonetheless, there they are and often in vast numbers. Areas of Colesdalen can have over 800,000 individuals of one species of collembolan every square metre.
Organic soils on Svalbard are generally extremely shallow, often less than 10cm deep. However, densities of animals can be very high. Tundra heath vegetation often has among the deepest organic soils and consequently greatest numbers of soil animals, up to 40,000 Collembola and 10,000 mites per square metre. In addition to the mites and Collembola, there are also various small worms present, both nematode and enchytraeid - small white worms varying between a few millimetres to a couple of centimetres in length.
Although polar semi-desert vegetation may appear more barren, it can often contain extremely high densities of soil animals. Densities of over 250,000 Collembola per metre squared are often found. This may be because although the soil is less deep, the open and free draining nature of the soil means that soil temperatures during the summer may be considerable warmer than in tundra heath vegetation and may approach 30oC.
The soil animals feed largely on dead organic matter, fungi, bacteria and each other. Since most require some form of soil they are usually found where there are plants and organic soil. Plants on Svalbard are extremely nutrient limited. The effect of nutrient addition is evident in how the plants have greened and have larger than usual leaves in this patch where a reindeer carcass lay for a few years.
The effect of nutrients on the vegetation is also particularly clear under bird cliffs where the nutrients from the bird gauno lead to abundant plant growth.
On a more limited manner, skua mounds often develop where arctic skuas have sat for generations on the look out for passing seabirds to attack. The guano deposited by these waiting birds enables the mosses to grow better and higher providing a better look out perch for the birds and so the cycle repeats. On the east coast of Svalbard skua mounds have been dated at several thousand years old.
Streams and ponds also provide a habitat for animals, including Crustacea such as the fairly shrimp, Lepidurus arcticus, and water fleas, Daphnia species but also the larvae of the non-biting chironomid midges.
also provide a potential habitat. Several studies from Svalbard have shown that the insect and mite fauna can be a little unusual. Some species on Svalbard are only known from bird nests.
Another unsual environment is around whale bones along the coast line. In some areas nutrients leaching out of these bones fertilise the plants which leads to an accumulation of organic soil and an special habitat for the soil animals.
Humans can also create unique environments suitable for both native and species introduced by humans. In the photograph we see a slope in the Russian settlement Barentsburg with many accidentally introduced plant species. 23% of the identified invertebrates at this site have not been seen from other locations in Svalbard and are considered to have been imported to Svalbard from southern European Russia/Ukraine along with soil for the greenhouse in the town. Link to article (Polar Research)
An unsual microhabitat with a diverse invertebrate fauna are the glacier mice of Iceland. These glacier, a direct translation from the Icelandic jokla-mys, are moss balls growing on the surface of the glacier. Although glacier mice from Iceland have been shown to have Collembola (springtails), mites, nematode worms and tardigrades, similar studies on a very few mice collected in Svalbard by the UNIS AB:201 Arctic Terrestrial Biology course in summer 2013 have yet failed to find invertebrates present.