In early summer, the wetlands in Espoo treat us with a spectacle of vibrant colours and scents. Labrador tea bogs are like the nature's version of rhododendron gardens, because the two belong to the same genus of plants. The bank of a bog bond is spotted with bogbeans and marsh cinquefoils. The shady mire offers a perfect place for admiring miniature wood horsetail forests and, if you are lucky, listening to the melancholy singing of the Hawfinch.
Outside the busy summer season, bogs and marshes can offer our busy minds a place to quiet down and enjoy the present. In late autumn, there are not even horseflies or mosquitoes to make nuisance. Cranberries can be picked until there is snow and again in the spring after the thaw. In November-December, the continuously green Sphagnum-moss seems to downright glow. A few evergreen plants – the Pine, the Labrador tea, the Crowberry and the Bog rosemary among them – retain their leaves throughout winter. Winter moths, resistant to the cold, can be seen flying about still in November.
Endangered species and traces of the past
In Espoo, as elsewhere in Finland, about half of wetlands have been drained. Conservation of the remaining habitats is thus of paramount importance. Most wetlands in Espoo are bogs followed by mires and fens. They are primarily convex, oligotrophic highmoors or sedge marshes. In the depths of our wetlands there are hidden messages from our past, such as water chestnut nuts, a plant which has not grown in Finland in thousands of years.
With the declining natural wetlands, also their native species have become endangered. In Espoo, such species include the Oblong-leaved sundew, the Marsh helleborine and the Herzodiella moss. Bog bonds are the preferred habitat for the Red-throated diver and the Leucorrhinia albifrons, strictly protected under the EU Natural Habitats Directive. Many of the most prestigious wetlands in Espoo are protected by law. These include, among others, Tremanskärr, Pitkäsuo in Luukki, and the Matalajärvi fens and swamps. Many regionally valuable wetlands remain unprotected, however.
Tremanskärr – pearl of Espoo mires
The flagship of mire habitats in Espoo is the 45 ha Tremanskärr, a Natura 2000 network site. Thanks to the conservation, it has retained its natural state and remains one of the most versatile wetland areas in the Helsinki Metropolitan Area. The easiest way to explore the Tremanskärr mire is to walk the self-guided nature trail.