Balticsea 2020

Restoration of vegetation clad bottoms

One of the clearest signs of eutrophication in the coastal zone is the disappearing of bladderwrack and vascular plants from the inner archipelago protected environments. It is a serious problem thus these plants serve many important ecological functions. According to the Swedish Water Framework Directive, a lush plant society is essential for a good ecological status. The Swedish Water Ecologists, in collaboration with researchers at Stockholm University and the Baltic Sea Centre, has launched a project in which the vegetation area in the bay of Björnöfjärden will be improved.

The importance of the plants
A condition for good ecological status according to the Water Framework Directive is a lush plant society. In the Baltic Sea the vegetation of macro algae, crane algae and vascular plants, fills many important ecological functions. The plants creates e.g. critical environments for the wildlife in and by the sea. Among the plants a variety of small invertebrates thrives that are food for many fish and bird species. The fish search for vegetation-clad bottoms both in search for food but also for appropriate spawning grounds. The vegetation clad bottoms also attracts herbivorous birds and birds that hunt fish. The bottom vegetation in coastal areas also reduces nutrition from land and other emissions. On soft bottoms the plants also stabilize and prevent damages on the sediments and contribute to a better water quality (clearer water).

Implantation of species that earlier have declined or disappeared as a result of eutrophication in the bay of Björnöfjärden can speed up the restoration so that the bay regains a good ecological status. Suitable species for implantation is bladderwrack and vascular plants, which occurs naturally in the bay and serve important functions in the ecosystem.

Aims and objectives
The overall aim of this project is to examine (1) the conditions for successful implantation of important species when the water quality in the bay of Björnöfjärden is improved, (2) identify cost-implantation methods of these species, and (3) identify the effect of algae establishment ability, species diversity and area coverage.

The goal is an improved water quality in the bay of Björnöfjärden with clearer water so that the bay regains a rich vegetable- and animal life.

Living coast
For more information about the project Living coast, click here, and read more about the measures to improve the ecological status in Björnöfjärden.