Denmark - Geography and the Environment

Denmark - Geography and the Environment - Animal Life

Denmark
5. Geography and the Environment
5.8 Animal Life

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5.8.1 The Development of the Fauna
5.8.2 Preservation and Nature Conservancy

Animal Life The temperate northern coastal climate and the mostly fertile soil in a gently undulating landscape divided by fjords and sounds, together with the late arrival of flora and fauna in Denmark (after the last ice age) provide the most important conditions determining the animal life on which, today more than ever, Man has made his mark. On land, Danish animal life is clearly affected by intensive agriculture, urban development and the consequent pollution. At sea, human influence is seen especially in fishing, the discharge of sewage and the addition of nutrients, principally nitrates stemming from agriculture.

The Development of the Fauna [top]

Along with the soil, damp, mild winters and cool summers have determined the natural types of vegetation. Originally, 80-90% of the country was covered by a mixed deciduous forest. Danish animal life was therefore predominantly a forest fauna, as it still is when reckoned in the number of animal species.

The undisturbed forest contains many species which, in a complicated food chain, make use of the high and stable production of the forest so that scarcely anything is wasted. The forest is characterised by many specialised and often rare species. This is not true of the modern, rationally run and often planted forest. The lack of large, dead or dying trees and branches, together with a reduction in the number of wet areas, has led to a reduction in the number of animal species in these new forests.

It is impossible to determine accurately the total number of animal species in Denmark. In 1995 the National Forest and Nature Agency estimated the number of free, naturally occurring and breeding species of vertebrates in Denmark at 424, including 49 mammals, 209 birds, 5 reptiles, 14 amphibians, 37 freshwater fish and 110 saltwater fish. Far more uncertain is the estimated number of invertebrates, put at 21,000, of which insects alone account for 18,000. In 1997 the Danish catalogue of plants and animals most in need of protection showed that 54% of these had their habitat in the forest. This includes, for instance, the pine marten and 14 other species of mammal, 74 species of bird, 2 species of reptile, 5 species of amphibian, 15 species of freshwater fish and 964 species of beetle. These latter make up 26% of the beetles in need of protection.

Forests were formerly the dominant type of landscape; today it is agricultural land which covers almost 2/3 of the land area. Taking area into account, it is the fauna found on agricultural land which is most significant in Denmark. This may well be true in terms of the number of individuals, but is far from true in terms of the number of different species. The fauna found on agricultural land consists of a limited selection of species from the original fauna, supplemented by several other species introduced or advented by Man.

Whereas stability used to be a characteristic of the undisturbed forest, allowing many specialist species to settle and adapt, the conditions on agricultural land are, in contrast, very unstable. Fields are treated mechanically and chemically several times a year, and the vegetation cover is removed and changed, often annually. As a result, only a limited number of species can survive solely in cultivated areas. A large proportion of the animal life on agricultural land is consequently dependent on the availability of small biotopes in the form of live hedges, field margins, ponds, spinneys and other not cultivated areas.

Perennial crops, a minimal use of fertiliser and pesticides, and a closely interrelated and varied pattern of small biotopes are what produce the most abundant animal and plant life. But until recently, the trend has been in the exactly opposite direction. In future years some improvement is expected as a result of changed agricultural support systems and more active nature protection.

The hare, the partridge and the skylark presumably spread throughout the country in the wake of cultivation. The steep decline in these species in our days is probably due to the decreasing variation in crops, the decline in the number of biotopes and a reduction in the food available as a result of pesticides.

The drainage of wetlands as a result of agricultural methods has had a drastic effect on the fauna. In agricultural land, between 95% and 98% of the original wetlands have disappeared during the course of the 19th and 20th centuries. This is significant when we seek to explain why 5 out of 14 Danish amphibian species are today considered to be in need of protection.

The urban landscape becomes increasingly impoverished in fauna the nearer we come to the city centres, where the pigeon, the sparrow and the rat are the only vertebrates certain to be found. But in a country with no mountains, buildings in the cities can provide homes for species such as rock doves, black redstarts and swifts that would otherwise be rare or no longer exist.

In the residential areas on the outskirts of towns, there is a far greater variety of animal life. Although the number of species is still limited, the number of individuals per unit of area is very high. Here we find foxes, hedgehogs and house martens in addition to an array of birds species of which the most common are the house sparrow, tree sparrow, blackbird, great titmouse and starling.

Denmark has a sea area of 104,000 square kilometres and a land area of 43,000 square kilometres, meaning that around two thirds of Denmark consists of sea. What animals can thrive there depends, among other things, on the depth of the water, the current and the salinity. The almost ocean water of the North Sea, with a salt content of 3.5%, has a far greater number of species (approximately 1500) than the brakish waters to the east of Bornholm, where the salt content is under 1% (around 200 species).

Danish waters are generally shallow; only in the Skagerrak does the depth exceed 100 metres. The bottom is usually soft and consists of sand or mud. This leads to a relative paucity of marine species, something that has not been improved over the last few decades by the arrival of large quantities of fertiliser from land. Large parts of the sea bed are now affected by an annual reduction in oxygen, and are no longer able to provide a habitat for perennial fauna. The fauna is richer in shallow waters, where the oxygen conditions are better, especially on reefs and mussel beds.

Marine animal life is rich and varied: Plankton, such as jellyfish and copepods float in the water; nekton such as porpoise, cod, herring and plaice swim around freely; sea-bed fauna can be divided into in-fauna in the seabed such as cockles and lug worms, and epi-fauna on top of the seabed such as common mussels, crabs and starfish.

Finally, there are seals and sea birds. Due to the combination of low coasts, shallow water, currents, salinity and nutrition, the Danish waters are unique in international significance as resting grounds or wintering grounds for sea birds. Over 20% of the total number of individuals of some 28 bird species appear in Danish waters every year. Many other species of migrant water birds are dependent on the Danish waters and coasts, making the regulation of hunting and other activity in these areas an important international responsibility for Denmark.

Lakes, rivers, marshes, dunes, moorland and salt meadows are all homes to specific animal and plant life. The first three are by nature highly nutritious and therefore both productive and home to many species. However, the injection of large amounts of fertiliser via water and air has generally had a negative effect on the number of species in all habitats. This is especially true in the case of rivers, where the further establishment of obstructions in the form of dams and water mills over the centuries has meant that most of the Danish migrant fish today need special attention. Thus sturgeon, alice shad, twaite shad and white-finned miller's thumb have disappeared from Denmark within the last hundred years.

Preservation and Nature Conservancy [top]

Danish animal life is typical of a densely populated industrialised society. However, an ever more efficient management regime for the natural environment is under development, and consideration for the environment is being incorporated into the individual social sectors. The growing efforts being made to improve conditions for animal life are desperately needed. Conservation is needed for certain species such as the cormorant, the numbers of which, after it was protected in 1980, grew from 2000 to 40,000 pairs in 2001. In the case of other species, such as the fire-bellied toad, the need is for the re- establishment of its habitats.

For other species the primary need is a more general change towards being "nature friendly" in terms of production and the organisation of society. This applies especially to the animal life in the forests and on agricultural land. More untouched areas of forest, perennial crops, permanent pastures and other extensively exploited areas will have significance for the fauna, both the forest fauna of which there are many species, and the agricultural fauna so rich in individuals.

For all species of animal, as for nature as a whole, it is true that their continued presence and distribution in Denmark is in the hands of man more than anything else. In an intensively exploited land (and sea) such as ours, it is thus a social and political question as to how much and what kind of wildlife we want.

Peder Agger

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