PROJECT DESCRIPTION
BACKGROUND
According to the most recent Article 17 report of the Habitats Directive, the conservation status of the thick shelled river mussel (Unio crassus) is “unfavourable – bad” in both Denmark and the wider Continental biogeographical area. Until recently the species was considered to be extinct in Denmark. However, in 2004, it was discovered at one major water course (Odense Å) and more recently (2007) in the Torpe Kanal, a tributary to the Suså river system.
Currently the Suså river system is unfavourable to the river mussel due to a number of threats such as poor physical conditions and a lack of continuity. In addition the host fish, common minnow (Phoxinus phoxinus) and bullhead (Cottus gobio), for larvae (glochidiae) are not present in the water course.
OBJECTIVES
The main objective of the UC LIFE Denmark project is to contribute to obtaining a favourable conservation status of the thick shelled river mussel in Denmark and in the Continental biogeographic region.
This will be achieved by increasing the number of available habitat areas for the species and by reintroducing it into the Suså river system.
At a secondary level, the project will also benefit endangered habitat types (Annex I-listed) of the EU Habitats Directive, such as water courses of plain to montane levels and Hydrophilous tall herb fringe communities and the Annex II-listed fish, brook lamprey (Lampetra planeri), and spined loach (Cobitis taenia) – hence the designation of the Suså site within the Natura 2000 network.
Expected results: Overall, UC LIFE Denmark will contribute towards a favourable conservation status of the thick shelled river mussel. Specific expected results include:
Physical water course improvements on c. 18 km, enabling appropriate bottom substrate and continuity conditions for the river mussel and its host fish; A comprehensive stocking programme of the host fish. Minnows and bullheads infected by mussel larvae and released into the river system will create a starting point for rebuilding a viable, reproductive population of the river mussel on 18 km; The population of the thick shelled river mussel will be increased from zero to c. 0.1-0.2 individuals/ m2 of water course during the project. This is equivalent to about 10 000 new individuals; Through the combined efforts of improved physical conditions and reintroductions, the project will result in coverage of the river mussel in one additional water course system (it is currently found in two water course systems in Denmark). The population and the gene pool will be markedly more robust at the national level; By reintroducing host fish into the Suså water course, the reproductive cycle of the thick shelled river mussel will be secured after LIFE; Following the project, the sites will continue to be protected by the Nature Protection Act. This, together with their Natura 2000 network designations will ensure the highest legal protection; There will be an increase in the diversity of other habitat types; There will be public awareness of water course biodiversity in Denmark and the EU through a targeted communication strategy that includes public meetings, information boards and a website; In the context of a functioning ecosystem, the project will also support improved genetic diversity and act to encourage ecotourism; and It will encourage best management and restoration practices through networking with similar projects in Europe.
