Summary Core area of the site is pool with standing freshwater, which acts as reservoir of sewage plant. Site is nationally best breeding area for two species: Gallinula chloropus and Anas strepera, and one of the best for Podiceps auritus and Larus ridibundus.
Site description Suomenoja has been earlier a bay of sea with river estuary. The bay was separated from the sea and river by dams in 1960’es. Core area of the site is now pool with standing freshwater, which acts as reservoir of sewage plant. The pool gets temporarily water influxes from communal sewage and very rarely from the sea (when water level of the sea rises very high). Next to the pool are pasture and reedbed flooded regularly by sea. SIte includes also few hectares of ruderal land and alluvial forests.
Key Biodiversity The status of Suomenoja as a nationally important bird area was published in 2002 (report by Leivo et al 2002). At that time site was recognised important as holding nationally significant numbers of Gadwall Anas strepera, Moorhen Gallinula chloropus and Great Reed Warbler Acrocephalus arundinacea. Additionally the site was known holding 11 pairs of Horned Grebes Podiceps auritus, 850 pairs of Black-headed Gulls Larus ridibundus (Lammi & Routasuo 2001).
Values of the Suomenoja have apparently improved during last decade and values are also better known, as being more intensively monitored during last decade. The statement of Finnish Environment Research Centre (Pekka Rusanen, 28.11.2005) and further monitoring data, with over 3000 records (!) of this site in database of BirdLife Finland (Tiira, introduced in 2006), have revealed following values:
- Suomenoja is one of the most important breeding site for Horned Grebe Podiceps auritus in Finland (18 pairs in 2005, 16 pairs in 2007, being nationally third best place for the species in overall number and nationally best place in population density). Suomenoja holds about 1 % of national population and 0,3 % of population of EU. Species is listed in Annex I of Birds Directive.
- Suomenoja is known nationally most important breeding site for Moorhen Gallinula chloropus (about 14 pairs in 2005, 25 pairs in 2007, which means about 10-20 % of national population). Species was classified vulnerable in the last assessment for national Red Data Book (Rassi & al 2001).
- Suomenoja is known nationally best breeding site for Gadwall Anas strepera (12 pairs in 2005, 23 pairs in 2007, which means 2-5 % of national population).
- Suomenoja is populated by one of the biggest breeding colonies of Black-headed Gull Larus ridibundus (2400 pairs in 2005, 3400 pairs in 2008, which means about 2-5 % of national population). Species was classified vulnerable in the last assessment for national Red Data Book (Rassi & al 2001).
- Suomenoja is also one of the few regular breeding places of Great Reed Warbler Acrocephalus arundinacea in Finland, with 1-3 territories annually, which mean 1-10 % of national population. Species was classified vulnerable in the last assessment for national Red Data Book (Rassi & al 2001).
Suomenoja is also one of the best reproduction site for waterfowl in Finland if the effect of area is taken into account. At least five broods per hectare are raised annually. Good reproduction is documented at least by Horned Grebe, Moorhen, Gadwall and Black-headed Gull (Tiira, database of BirdLife Finland) and some commoner species (Coot, Shoveler, Goldeneye etc). Because of good reproduction, Suomenoja is definitely vital source of breeding populations for other breeding sites, thus making it enormously valuable. Place is true “hotspot” with corea area (the pool) being only 18 hectares in size. The protection of this site would be cost-efficient, as good reproduction and relatively very high numbers of mentioned species of conservation concern overlaps in small area. Small size makes the site vulnerable to development projects.
Rivers and streams; Standing freshwater; Water fringe vegetation
Artificial - terrestrial
Alluvial and very wet forest; Mixed woodland
Land ownership Municipality of Espoo and Fortum (powerplant owner next to the site).
Extent (% of site)
References Lammi, E. & Routasuo, P. 2001: Monitoring the bird wetlands of Espoo municipality in 2000. – Environment Council of Espoo municipality, publication 1/2001 (in Finnish, 65 pages)
Leivo, M., Asanti, T., Koskimies, P., Lammi, E., Lampolahti, J., Mikkola-Roos, M. & Virolainen, E. 2002: Finnish important bird areas – FINIBA. – BirdLife Finland’s conservation publication nr 4 (in Finnish, 142 pages).
Rassi, P., Alanen, A., Kanerva, T. & Mannerkoksi, I. (editors) 2001: The 2000 Red List of Finnish Species. – Ministry of Environment and Finnish Environment Research Center. (in Finnish, 432 pages).
Rusanen, Pekka 2005: Statement of values of the Suomenoja. – Annex in the complaint made on the plan of harbour, next to the FINIBA-site Suomenoja.
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