PROJECT DESCRIPTION
BACKGROUND
The huchen or Danube salmon (Hucho hucho), the largest central European salmonid, whose natural habitat is restricted to the Danube river system, was once widespread in Austria but is now in danger of extinction. Whereas previously stock depletion was due mainly to water pollution and overfishing, today other factors are responsible: barriers like dams often present insurmountable obstacles for spawning fish and prevent exchange between subpopulations, while watercourse regulation has led to the loss of important spawning and feeding grounds. Since the species has all but disappeared in Bavaria, the remaining natural huchen stocks in the four Austrian Danube tributaries Mur, Pielach, Drau and Gail were the largest in the European Union in the late 1990s. The project area covers the middle and lower stretches of the Pielach and Melk/Mank rivers in Lower Austria, with a total length of 45 km. Whereas some stretches of the Pielach are still in their natural state, the Melk has been altered considerably by regulation and canalisation works.
OBJECTIVES
The aim was to improve migration opportunities for the huchen and other endangered river fish such as Chondrostoma nasus and Barbus barbus over a total length of 78 km by opening up the Pielach and Melk/Mank rivers and linking them with the freely flowing stretch of the Danube in the Wachau district. This would be done by removing or altering weirs and other obstacles so that fish would be able to pass through. In addition to these main measures, it was also planned to create buffer strips along the banks of meanders so that fluviatile dynamics (e.g. bank erosion) do not conflict with agriculture and other land uses, and suitable spawning grounds are formed. All this was to be implemented in close cooperation with the water authorities, and involving landowners and holders of rights to use water. The project counted on the support of licensed anglers who had been campaigning for the preservation of the huchen for years. The municipality of Loosdorf, the Austrian Friends of Nature, WWF and the Federal Environment Ministry would bear part of the costs - an indication of the broad base on which the project was founded.
RESULTS
This project achieved its targets as regards the central objective of improving fish spawning migration on the rivers Melk and Pielach. 11 obstacles to fish migration (weirs and river thresholds) were adapted through the removal of thresholds or the construction of fish by-passes. A river continuum 78 km long has been created. As a result, Danube fish are again able to enter freely in both rivers during their spawning migrations. This was confirmed by the results of the monitoring carried out as part of the project. The project exceeded targets as regards its second objective, the purchase of alluvial land and buffer strips for habitat restoration (through river bed enlargement and planting alluvial forests). 75 ha land was purchased, well in excess of the original target, and which will allow the river dynamics to continue in the future. The third objective was the restoration of 2.6 km of regulated river sections at Mank and Melk. Whereas the regulated river's structure was a simple v-shaped channel, the restored river is much closer to a free-flowing natural stream with many different types of river habitats (deep, shallow, fast-flowing, slow-flowing sections etc.) and a variety of river substrates. In both sections, at Mank and Melk, the project carried out an initial restoration - in the years to follow the river dynamics will continuously change the morphology. The effects on the target species were positive: spawning of the fish Chondrostoma nasus was observed for the first time in 2004 in the Mank river section, while by project end the otter was regularly using this restored section for feeding and hunting. On the Melk section kingfisher, little ringed plover and goosander started to breed (again). Fish ecological monitoring was carried out since 1999: the University of Natural Resources and Applied Life Sciences of Vienna was responsible for a fish status quo ante inventory, structural mapping of the riverbed (68 ha mapped), a fish migration survey and monitoring of the impact of the restoration works on fish populations. Daily fish monitoring results could be seen on http://homepage.boku.ac.at/zitek. Altogether, 3,434 individuals (38 species) were caught at 9 fish migration infrastructures. Further outputs of the LIFE project include: Management plan laying down monitoring and mapping of vegetation, amphibians, fish, otter and river mussels and management guidelines for subsites which need recurring management (restored river sections, alluvial strips). It covers the implementation of LIFE actions and the long-term management after LIFE. This management plan was earmarked to be used as a model for the elaboration of Natura 2000 management plans, and its results would be used for the update of the Natura 2000 data forms as well. Website with home page http://www.life-huchen.at Project folder (3000 copies) Topical folders with titles “river continuum”, “freshwater habitats”, “management of river bank trees” and “river bed load”. Individual meetings with political decision-makers, anglers, tenants of water rights, farmers and foresters. Information meetings with the municipal councillors in 5 communes - Melk, Loosdorf, Hafernbach, Zelking-Matzleinsdorf and St. Leonhard. Numerous individual and several group meetings with the landowners of land sections in the alluvial sub-sites "Neubacher Au" and "Mühlau". (for all meetings with locals, DIN A4 information flyers were distributed, explaining the project concept and the specific local actions in detail). A nature film with the title "Die Pielach - ein Juwel unter Österreichs Flüssen", entirely devoted to the LIFE-Nature project. The film was also presented during local information events in the Pielach valley. Information panels at five different sites within the project area, with additional panels on 12 sites (LIFE and Natura 2000 explanations included). Presentation of the LIFE project at the open days of the commune Melk. Itinerant exhibition (6 posters) about the project in the Melk valley. About 50 press articles and several TV broadcasts.