En uppföljning av floran i Enköpings vattenpark
kan anlagda våtmarker med vattenrening som huvudsyfte bidra till naturvård och biologisk mångfald?
Wetlands are important ecosystems and form habitat for both common and threatened species. In Sweden, as well in many other places on earth, there is a lack of wetlands. There is an expressed will to adjust this lack through restoration of wetlands with reduced function and through construction of new wetlands. Follow-ups and evaluations are important steps to optimize these actions. The wetland Vattenparken was constructed 1999 ? 2000 for treatment of surface water. During the construction a big effort was made to ensure the benefits for biodiversity, mainly through planting of wetland vegetation and introduction of wetland plant species.
This study involves an inventory of the flora of the constructed wetland Vattenparken that was made in the summer 2008. The goal with the study is to evaluate the contribution of the wetland for biodiversity. The result of the inventory shows that the wetland includes a high number of species but a very uneven distribution. Cattail (Typha latifolia) and common reed (Phragmites australis) was found to dominate and these two species cover more then half of the inventoried area. The different types of planting have a significant effect on number of species and on diversity. The wetland Vattenparken has a positive impact on biodiversity in the region, probably also on other groups of organisms than plants, such as birds, reptiles and evertebrates. Though, there is a risk of an ecological community with more uniform structure and with less species in the future, because of competition from increasingly dominant plant species.
Arrangements which are supposed to increase the conditions for a high biodiversity in the wetland Vattenparken is to eliminate the common reed (through mainly mechanical methods as mowing) and introduce naturall variations of the water-level. A proposal for new constructed wetlands is to build two connected systems of pools where biodiversity and water treatment are optimized separately. Consequently, naturally hydrology can be maintained to create a viable habitat without risking the effect of the process of water treatment.