Urban areas are a variable habitat type and somewhat open to different interpretations. It is estimated however, that in Finland their area covers approximately 1.4 million hectares which equals to 3.5% of all habitat types. The share of urban habitat species of all well-known species in 11%. This is notably more than could be espected from their share of total area. Parks, yards and gardens are a primary habitat for 44% of urban habitat species. Ruderal environments, road edges, railway terrace and gravel pits are inhabited by 42% of the species. The remainig 9% occur in buildings and structures.
Parks, yards and gardens are species-rich habitats. They are a secondary habitat for many demanding species, such as beetles, fungi, butterflies, flies and mosquitoes as well as ants, bees and wasps. Some vascular plants and fungi also favour these habitats. The species living in buildings are mainly beetles, butterflies, fungi and lichens. Ditches are inhabited by mosses, but also vascular plants and mosquitoes and flies.
The abundance of species is often higher in urban areas than in the surrounding scattered settlements or rural area. The large number of species is thought to be due to the diversity of urban habitats and the abundant and repeated disturbance caused by human activity. Disturbances maintain the early stages of succession. In addition, urban habitats typically host several invasive species.
What and where?
Urban areas mean most of all population centres and industrial areas as well as habitats in their immediate proximmity. In addition, the surroundings of roads, harbours, airports and other traffic concentrations are included. Urban habitats are dependent on human activity which changes the landscape and habitat conditions. Then again, urban areas are often built on valuable natural state environments which may become endangered as for example cities expand. Intensifying landuse, erosion and the increasing nutrient loads also threaten the species wich otherwise favour urban areas.
Urban areas can be found almost everywhere in Finland, but their share is the most significant in southern Finland. In the county of Uusimaa, urban areas cover 14.2% of such area wich does not include sea areas, and in Varsinais-Suomi 10.2%. The corresponding share for the two northernmost municipalities of Inari and Enontekiö in Lapland is 0.3%.
- Updated (14.05.2013)