A new approach: a gradual, ecological freshwater-saltwater transition between Wadden Sea, IJsselmeer and the hinterland

PROJECT DESCRIPTION

BACKGROUND

In the past, Europe had an estuarine coastline characterised by gradients and natural dynamics. Together with rivers in the hinterland, these coastal waters formed a natural system. For fish, the estuarine area was a vital link in migration routes between the sea and these rivers, while birds used the area to breed, forage and live. After dams, dikes and engineering structures were put up, disturbing the coastline. Open connections were blocked and the estuarine area disappeared. In the Netherlands, the construction of the Afsluitdijk created a barrier between the Wadden Sea and the IJsselmeer. As a result, the interconnected natural system disappeared. As a consequence, it is difficult or impossible for fish to migrate and birds have fewer suitable habitats than before. This applies to the Wadden Sea and the IJsselmeer, but also to the surrounding polder and belt canal systems and rivers in the hinterland, such as the IJssel and the Rhine.

OBJECTIVES

The Fish migration & BirdLIFE project aims at the restoration of a natural river course – to encourage fish migration – by restoring the connectivity between the Wadden Sea and the IJsselmeer. The concrete conservation actions will consist of the natural landscaping of the fish migration river and the creation of breeding islands and high-tide resting areas for birds. These project actions will:

Restore estuarine conditions in the transition between the Wadden Sea and the Ijsselmeer. These actions target fish species that use the Ijsselmeer as an acclimatisation zone and habitat in their migration route between the Wadden Sea and the wider Rhine river basin, and also benefit bird species that use the estuarine area to breed, forage and live;

Increase food availability for birds in and around the Ijsselmeer; and

Increase the number of breeding and high-tide resting areas for birds in the Wadden Sea.

The targeted species are designated in the Habitats and Birds directives for the IJsselmeer and/or Wadden Sea Natura 2000 network sites; their conservation status is unfavourable. The European eel is not included in the annexes of the Habitats Directive, but has a status of “critically endangered” in the European Red List. The project will contribute to population growth of eight fish species and 26 bird species (11 breeding and 15 non-breeding species), of which two fish species are priority for conservation listed in annex II of the Habitats Directive and one (breeding) bird species is listed as a priority in the Birds Directive.

By creating estuarine conditions, the impact of rising sea levels and changing river discharge regimes due to climate change in the fish migration river will be minimised.

Expected results:

Fish migration:

70% of the fish that, before the project, were halted behind the sluice will use the naturally landscaped fish migration river within five years of completion;

Improved species’ conservation status for: sea lamprey (Petromyzon marinus), European river lamprey (Lampetra fluviatilis), allis shad (Alosa alosa), twait shad (A. fallax) and Atlantic salmon (Salmo salar); and

Populations of other fish species, including, the houting (Coregonus oxyrinchus), European sea sturgeon (Acipenser sturio) and European eel (Anguilla Anguilla), will also benefit.

Food availability:

Increased fish populations in the Ijsselmeer; and

Bird species in Natura 2000 network sites around the Ijsselmeer will benefit.

Habitat (bird breeding ground and resting areas):

10% population growth for: common tern (Sterna hirundo), sandwich tern (Thalasseus sandvicensis), little tern (S. albifrons) and Arctic stern (S. paradisaea) - breeding;

5% population growth for: great bittern (Botaurus stellaris) - breeding, great crested grebe (Podiceps cristatus), great cormorant (Phalacrocorax carbo), little gull (Hydrocoloeus minutus), black tern (Chlidonias niger), goosander (Mergus merganser), smew (Mergellus albellus), teal (Anas crecca), Eurasian wigeon (A. Penelope), pintail (A. acuta), eider (Somateria mollissima), oystercatcher (Haematopus ostralegus), avocet (Recurvirostra avosetta), Eurasian curlew (Numenius arquata), redshank (Tringa tetanus) and ruddy turnstone (Arenaria interpres) - non-breeding;

5% habitat increase (riparian zone) in the Ijsselmeer; and

Restoration of breeding grounds: western marsh harrier (Circus aeruginosus), sedge warbler (Acrocephalus schoenobaenus), ringed plover (Charadrius hiaticulas), Kentish plover (C. alexandrines) and common eider (Somateria mollissima).