Status and trends of biodiversity, including benefits from biodiversity and ecosystem services
Denmark is home to about 30,000 species of plant, fungus and animal. In terms of natural ecosystems, Danish woods are both deciduous and coniferous with a high proportion devoted to plantation or production forest. The forest ecosystem is considered the most diverse national ecosystem and presents considerable species richness. Coastal ecosystems are also unique because of the 7,000 km long dynamic coastline, continuously reshaped by erosion and deposition, with succession in built-up areas, lagoons and salt lakes. Species richness of invertebrates in marine areas is very high, with more than 500 species in Denmark’s inner waters, despite variations between local areas.
Yet Danish biodiversity is nowadays in net decline. Currently, 6,367 species in 8 major species groups have been assessed according to IUCN Red List criteria, and 1,514 or 23.7% of these have been red-listed. In agricultural ecosystems, trends are negative for 22 species of farmland birds, brown hare, vascular plants of small biotopes, butterflies, bumble bees and beetles. The area occupied by open habitat types, such as commons, heaths, bogs and sand dunes is decreasing; 66% have a poor conservation status and their area has fallen from 12.5% in 1965 to 9.2% in 2000. In contrast, forests are in a rather good conservation status, and forest area is even growing as a result of reforestation policies. A survey for the 2001-2006 period indeed shows that, out of 9 forest types in Denmark, as specified in the EU Habitats Directive, 6 have favourable, 1 has moderately unfavourable, 1 has unfavourable and 2 have unknown conservation status. Nevertheless, forests constitute 52% of the habitat affiliations for red-listed species and, while undisturbed forest is today estimated to account for 7% of Danish forest, only 1.6% of it enjoys direct protection. In terms of aquatic biodiversity, there have been marked improvements in species diversity in watercourses, with the incidence of the most sensitive small animals (caddis fly (Trichoptera), mayfly (Ephemeroptera) and stonefly (Plecoptera)) increasing by 23% in Danish watercourses between 2000 and 2007.
The conservation status is unfavourable for all 5 types of lake listed by the Habitats Directive and for 1 of 2 watercourse types. Of the 14 terrestrial habitat types in coastal zones, the conservation status is unknown or not evaluated for 7 types, favourable for 2 types and unfavourable for 5 types. Finally, the number of seabed species more than halved between 1994 (almost 14 species per sample) and 2007 (6.5 species per sample).
Though part of the Kingdom of Denmark, the Government of Greenland has management responsibility over, amongst other things, biodiversity and living resources. Eighty-five per cent of Greenland is ice-covered, 15% ice-free. There is a large range of terrestrial habitat types (including heath, scrub, forest, snow-bed, herb-slope, grassland, steppe, mires), resulting in a diversity of living conditions for terrestrial organisms. Melting of glaciers and the Ice Cap, as well as summer rainfall create a range of freshwater habitats (e.g. homeothermic springs and saline lakes). The status of all habitat types has been assessed as favourable. Yet 3 species/subspecies/discrete populations are categorised as extinct or regionally extinct, 6 as critically endangered, 3 as endangered, 12 as vulnerable and 12 as near-threatened and the above-mentioned freshwater habitats face threat from the proximity of human settlements.
Biodiversity offers considerable benefits. In Greenland, for example, traditional hunting is of significant socioeconomic importance and central to the cultural identity of the people. Fishing notably is the lifeline of Greenland and the primary industry in the country, with 90 % of all export deriving from it.
Main pressures on and drivers of change to biodiversity (direct and indirect)
Over the last century, extensive drainage and intensification of forestry for timber production has led to a significant net decrease in open forest glades, forest wetlands and structures related to old growth forests. Based on expert judgment, it is likely that the rare specialist species are declining due to a delayed negative response (extinction debt) to ongoing loss of habitats for these species, and due to a general scarcity of old growth habitats in the forests and plantations of the present day. The main threats to Danish watercourses, lakes, coastal and marine environment include maintenance, discharge of sewage and former practices to straighten and dam watercourses, introduction of agricultural nutrients, loss of natural disturbance caused by marine and wind erosion, cessation of grazing, construction of dikes, invasive scrub species threatening herbaceous dune and grassland habitats and de-oxygenation, bottom-trawling. Climate change also is an important driver of biodiversity change. Yet its effects on ecosystems are ambiguous. On the one hand, climate change is expected to have considerable impacts on food webs (notably in lakes), plant and animal composition (for instance, by enhancing the competitive exclusion of subordinate stress-tolerant plants and their associated herbivore insects, while denser and taller sward will limit the area of warm and sunny open ground, so critical to invertebrate diversity). It will impose an important future threat to coastal biodiversity, sea level rise leading to significant loss of low altitude coastal habitats. On the other hand, climate might benefit some ecosystems, such as forest ecosystems, through the increased occurrence of windfalls.
In Greenland, climate change constitutes a considerable threat. Average temperatures are predicted to rise by 2 degrees in southern Greenland and by 6-10 degrees in northern Greenland, with an increase in rain and snowfall of 10-50%. There is a risk that most of the high Arctic zone will be replaced by low Arctic conditions. Climate change is notably affecting the marine ecosystem: northern shrimp has already started to disappear from the waters off southern Greenland, while large stocks of northern cod are reappearing. Additional threats include environmental contaminants and, to some extent, habitat fragmentation, invasive species, increased shipping and air traffic, and regional development such as oil and gas exploration and production.