IW12 Directive inland water species
Status of Habitats Directive species
Inland waters offer a habitat for 28 Habitats Directive species. They represent a variety of species groups and occur both in lakes and ponds as well as rivers. More than a half of them are vertebrates. Invertebrates include eight insect species, two mussels, a crustacean and an annelid. Only two fresh water plant species are included in Habitats Directive. All species occur in the boreal region, and five of them - Otter, Common Frog, Whitefish, Salmon, Grayling and Freshwater Pearl Mussel - also in the alpine region.
In the alpine region, the conservation status of all five species is favourable. The state of the northern water systems has remained good in comparison to southern Finland, where human impact has overall been stronger.
Conservation status of most Habitats Directive species in the boreal region has been evaluated as favourable. These include European Beaver, Otter, frogs, fishes, European Crayfish, beetles and four dragonfly species. The status of six species is unfavourable-inadequate, and for the dragonfly Green Hawker still weakening. Even though the ranges of all boreal species has been evaluated as favourable, the conservation status of these six species has been weakened by the inadequate amount and quality of their habitats. In addition the populations of Freshwater Pearl Mussel, Green Hawker and the plant Najas tenuissima are in an inadequate state. The population of Slender Naiad is too poorly known for relevant assessment.
Lake Saimaa Ringed Seal is the only directive inland water species whose conservation status is inadequate-bad. During the assesment period (2001–2006) the population of Lake Saimaa Ringed Seal has been somewhat increasing, but it is still in a bad state. Also the future prospects of the species are weak. Conservation status of two species, European Medical Leach and the newcomer Siberian Winter Damsel, is unknown.
The most common threats to the viability of inland water species have to do with different kind of changes in water bodies and courses. These include dredging, drainage, clearence of aquatic and shore vegetation as well as regulation of watercourses. Decrease in water quality due to eutrophication and pollutants forms another threat. Eutrophication may also result in excessive plant growth, which is a significant threat to Green Hawker, for example. The Naiads are in turn harmed by competition with other species and European Crayfish by parasites.
Poor conservation status of Lake Saimaa Ringed Seal is a sum of several factors. In addition to general threats affecting the overall state of inland waters, seals are threatened by human disturbance and the risk of drowning in fishnets. In the future global change will probably have a negative impact on seal populations, since rising temperature weakens the wintertime ice cover on lakes. Lake Saimaa Ringed Seals have their young on ice and therefore depend on strong ice cover and snow for shelter.
Read more about inland water species IW11 Threatened species.
- Updated (14.05.2013)