Rönne å river

The main purpose with the LIFE CONNECTS in Rönne å river is to improve connectivity and river habitats to gain favorable conservation status for prioritised Nature 2000 habitat types and species, especially Atlantic salmon, Freshwater pearl mussel and Thick-shelled river mussel.

Rönne å river is one of the longest watercourses in Skåne Caunty with a length of about 85 km. Along with its tributaries, the river also has one of the largest catchment areas of 1,897 km2. The river runs from it sources at the lake Ringsjöarna through a largely flat landscape dominated by agriculture and deciduous forest to enter in the Gulf of Skälderviken in Kattegat at Ängelholm city. There is a distinct change in geology about 38 km upstreams from the coast where rock formations create impressive rapids with unique habitats. Because of the migration obstacles in the river, many migratory species have not been able to reach these environments during the last 70 years.
As in most watercourses in Skåne County and in many other parts of the country, the river has been affected by human activity for a long time through damming, straightening and cleaning of riverbed substate. In Rönne å river, there are several definitive migration obstacles , the first already 38 km from the sea, which has contributed to the absence of  migratory fish in the system and decreased sediment transport to the sea. Fish passages have never been installed at these obstacles, which means that species such as Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) have not reached the spawning and nursery areas in the upper parts of the river. Only the European eel (Anguilla anguilla) has been present in the upper part since it has been caught and transported upstream and downstream around the barriers. The salmon population in Rönne å river is unique since it represents an endemic strain, which, however, is expected to decrease in the future if the migration posibilities is not improved and the habitats restored. Rönne å river has a moderate ecological status (classification according to the Water Framework Directive, WFD) due to lack of connectivity, morphology and eutrophication.

Despite its moderate status Rönne river has high natural values in some parts of the river. In the river it has been reported around 22 fish species, including the Atlantic salmon,  Brown trout and European eel as well as European river lamprey (Lampetra fluviatilis), Gudgeon (Gobio gobio) and European minnow (Phoxinus phoxinus). Small populations of the threatened Freshwater pearl mussel (Margaritifera margaritifera) and Thick-shelled river mussel (Unio crassus) are present in tributaries today but are believed to have existed in headstream of Rönne å river previously. Rönne å river also has a high values ​​for terrestrial plants and animals living near the river, especially birds such as White-throated dipper (Cinclus cinclus), Kingfishers (Alcedo atthis) and Grey wagtail (Motacilla cinerea). A species that is protected according to the Habitats Directive, and which is now found in the Rönne å river after almost completely disappeared, is the Eurasian otter (Lutra lutra).
Within LIFE CONNECTS, measures will be implemented in the headstream and in three tributaries; Klövabäcken, Skärån and Ybbarpsån. The measures include the dismantling of three power plants, remediation of further minor obstacles to migration and river restoration in the form of block restoration and creating spawning grounds. In total, at least five migration obstacles will be addressed and around 35 km of river will be restored. When the migration obstacles are removed and fauna passages created, virtually all of Rönne å river will be open for fish migration and species such as Atlantic salmon and Brown trout will be able to reach the Ringsjöarna (the source) and several of the tributaries (about 100 km), which have nice spawning and nursery grounds. The measures will also contribute to the increase of flowing waters, which benefits streamwater living species and create more natural flows and structures. Together, it gives a significant positive impact on the hydrology, water quality and biodiversity of the river. Improved spawning and nursery habitats together with improved migration, even to tributaries, will increase the fish production enormously and thus improve the conservation status of salmon and eel. Total salmon smolt production is estimated to increase to over 17,000 individuals five years after restoration is completed compared to pre-restoration conditions. In addition, the restorations will increase the populations of host fishes and improve habitats for the river Freshwater pearl mussel and Thick-shelled river mussel.

In Rönne å river, there are both larger and smaller Natura 2000 sites with the nature 2000 type “Waters with floating leaf vegetation or aquatic mosses” (Nature 2000 code 3260). Designated Natura 2000 species are the beetle Graphoderus bilineatus, Northern crested newt and Eurasian otter.
When the effects of the measures show favorable conservation status, the management plan for the Natura 2000 sites will be revised. Similarly, the plan for national interest in outdoor recreation will be revised. Rönne å river is a popular place for fishing, canoeing and hiking. Many tourists from all over the world visit the area every year to see and experience the beauty and power of the Rönne å river. LIFE CONNECTS will inspire more people to visit and experience the river.

This post is also available in: Svenska (Swedish)