Kurjenrahka National Park includes the largest mires of Southwest Finland which are in their natural state, and the surrounding forests, of which some are old. The soil in the National Park is low in nutrients, which can be seen in the natural features of the area: the forests are mostly dry, and the mires are barren raised bogs, where the centre is higher than the edges, so nutritious water from the surrounding areas cannot run there. The plants of the raised bogs live only on the nutrients they get from the rain water.
Geographically Kurjenrahka National Park can be divided into three parts:
- The large raised bogs of Kurjenrahka and Lammenrahka,
- Vajosuo mire area with the forests on its edges, and
- the mires and forests in Laidassuo, Lakjärvenrahka and Pukkipalo.
The Diverse Mire Areas
The Mires in Kurjenrahka are unique to Southwest Finland in their size and diversity. Although some areas round the edges of the mires have been drained before now, most of the mire is still undisturbed. In addition, many of the ditches have become blocked, and the original vegetation of the mire is growing back.
This process can be speeded up by mire habitat restoration works (www.metsa.fi), such as blocking the ditches and felling the trees which have grown because of the mire drying.
The Diverse Old-growth Forest of Pukkipalo
The forests of the National Park grow round the edges of mires, or in forested islands in the middle of mires. Most part of the forests have been used for commercial forestry. However, there are many islands in the mires where the forests have been saved from logging for a long time, and they appear as if they were in their natural state: there are trees of different age, especially stout old trees, a lot of decayed wood, and many different tree species. Pukkipalo old-growth forest in the eastern corner of Laidassuo and Lakjärvenrahka mires is a good example of that.
Pukkipalo has the most handsome old-growth forests of the region. There are old spruces, dead standing barkless trees, and old decayed wood on the ground. In places which are higher than their surroundings, old pines with their shield bark grow as if they were guarding the peace of the area.
In the old-growth forests live the hole-nesting birds, many insects and fungi. The set of decay fungi species of Pukkipalo is impressive; the threatened species like Fomitopsis rosea and Amylocystis lapponica show, that there has continuously been a lot of decayed wood, which is rare in Southern Finland.
Even though the animals living in the National Park are mostly typical for mire areas, there also live many rare and threatened species of wilderness. Some of them are far away from their main distribution areas, for example for many northern bird species this is their southernmost nesting area.
The nesting birds of the National Park include many species which are rare or threatened in Southwest Finland, such as the Northern Hobby (Falco subbuteo), the Common Kestrel (Falco tinnunculus), the European Nightjar (Caprimulgus europeaus), the Grey headed Woodpecker (Picus canus), the Wood Lark (Lullula arborea) and the Red-breasted Flycatcher (Ficedula parva). A lucky passer-by can also see the Peregrine Falcon (Falco peregrinus) on top of a pine tree on a mire, or flying up in the sky. Kurjenrahka is probably one of the southernmost places in Finland, where the Willow Grouse (Lagopus lagopus) nests. In addition, the southernmost Rustic Buntings (Emberiza rustica) in Finland can be seen on the pine bogs and in the willow thickets around the mires.
In the old-growth forests on the edges of the mires, and on the forested islands, nest the Common Raven (Corvus corax), the Tengmalm's Owl (Aegolius funereus), the Ural Owl (Strix uralensis), the Black Woodpecker (Dryocopus martius), the Three-toed Woodpecker (Picoides tridactylus), the Black Grouse (Tetrao tetrix) and the Western Capercaillie (Tetrao urogallus). In the spring and autumn, many migrating birds stop on the mires of the National Park. For example the Bean Goose (Anser fabalis) and the Common Crane (Grus grus) rest in the area.
Butterflies and Beetles
In the old-growth forests live several rare beetle species, which depend on decaying wood. Especially Pukkipalo old-growth forest has a diverse set of beetle species. The threatened species of the area include Aradus betulinus, Aradus pictus and Calitys scabra. There are also rare and threatened moths such as Straw Belle (Aspitates gilvaria), and butterflies such as the Freija's Fritillary (Clossiana freija).
The Siberian Flying Squirrels (Pteromys volans) of the National Park live quietly in the old mixed-wood forests round the mires. They eat leaves, bark and pollen of the old deciduous trees, and hide in the spruces. The worst enemy of the Flying Squirrel in the National Park is the Pine Marten (Martes martes), but also the Northern Goshawk (Accipiter gentilis) and the Ural Owl (Strix uralensis) can be dangerous.
Lake Savojärvi, north of Kurjenrahka mire, is the territory of an Otter (Lutra lutra) couple. In the night, the Otter regularly goes on a foray from the Lake Mynäjärvi nearby to Lake Savojärvi and up to the head waters of Järvijoki River.
The National Park also has a permanent Lynx (Lynx lynx) population. The Moose (Alces alces), the White-tailed Deer (Odocoileus virginianus) and the Western Roe Deer (Capreolus capreolus) are common. Sometimes a lone Wolf (Canis lupus) or Brown Bear (Ursus arctos) might visit the park.
Kurjenrahka, Lammenrahka and Vajosuo Mires
Kurjenrahka, Lammenrahka and Vajosuo are raised bogs, where hummocks (higher and dryer places) are winding between wet hollows. On the hummocks grow the Marsh tea (Ledum palustre) and sparse tortuous pines (Pinus sylvestris). The hollows between them are at some places deceitfully soft and wet, real bogholes. "Rahka" in the names of the mires originates from the Finnish word for Sphagnum moss (Sphagnum sp), which is typical for these mires.
Kurjenrahka Mire, which the National park is named after, is with its area of more than 20 sq.km. one of the largest unbroken mires in the whole of Southern Finland. It is a raised bog divided by forested islands, and its wettest part, so called "puddle part", is the northern and western side of it. The puddles are small ponds on the mire, where many birds live. Because it is not easy for predators to get there, it is a safe place for the birds to build their nests.
Lammenrahka Mire, next to Lake Savojärvi, is a typical Southwestern raised bog, where dry hummocks and wet hollows circle the centre of the mire. At some places it is more luxuriant than Kurjenrahka Mire, and it also has many small ponds with clear water. On Lammenrahka Mire live probably more birds than anywhere else in the National Park. Separate Vajosuo Mire is a smaller raised bog, where the centre is flat with few trees, and on the edges there is a pine bog zone.
Laidassuo and Lakjärvenrahka Mires
Laidassuo and Lakjärvenrahka, located in the western part of the park, are completely different from the large Kurjenrahka and Lammenrahka areas. Here the mires have formed between large, rocky forests, usually as elongated chains.
The area of Laidassuo and Lakjärvenrahka Mires for most part resembles a labyrinth, at some places it seems wilderness-like. In between the mires, there are forested islands, some of them in their natural state, such as Pukkipalo old-growth forest area.