Ecosystems and climate change
Almost all of Finland is located in the northern boreal ecoregion of Eurasia with only the southwest and southern coasts and the Åland Islands belonging to the temperate mixed forest biome. Climatic conditions and the associated biotopes vary between the south and the north. Southern Finland is characterised by a more diverse range of species, variation between broadleaf, mixed, and coniferous forests, and scenery broken up by agricultural regions, roads, and cities and towns. Habitats that have become increasingly rare, such as old-growth forests, spruce mires, and cultural landscapes, are strongholds of biodiversity. Nature in the north is more barren and characterised by treeless fells, string bogs, and boreal coniferous forest. Lakes, rivers, and smaller water systems are common features throughout the country. Finland's long coastline with its maze of islands is sensitive to the effects of human activity, but the condition of the sea on the whole is affected by activity across the entire drainage basin of the Baltic Sea .
According to the 2008 conservation status assessment, a total of 188, or 51%, of the biotopes found in Finland are currently at risk of becoming extinct. The percentage of threatened biotopes is considerably higher in Southern Finland than in Northern Finland. A threatened status has been given to a total of 93% of cultural biotopes and 70% of forest biotopes. More than half of the marine and coastal biotopes of the Baltic Sea as well as bog biotopes have also been classified as threatened. The most important threats to biotopes include the effects of forest regeneration and management, drainage, eutrophication and contamination of water bodies, the ploughing-up of land, and hydraulic engineering .
Climatic conditions affect the structure of vegetation and the distribution of ecosystems within an area. Ecosystems can also be categorised according to limiting factors as either temperature-limited or water-limited. Other factors that affect ecosystems include interference by fire and pests, for example . Climate change can affect all these factors.
The effects of climate change are believed to be the most extensive or the fastest in environments characterised by snow, ice, and permafrost , which are found across Finland. Impacts on the Baltic Sea, inland waterways, coastal regions and wetland areas, bogs, forests, and fells will be the most substantial. Changes will also occur in agricultural ecosystems and cultural landscapes. Effects on rock outcrops and screes, for example, are expected to be less significant . Information about the effects of climate change on urban environments is still limited.