Seeuferrenaturierung

Abstract

Central European lakeshores suffer from intense human use. Extensive sections of shore line are degradated by land fills, bank reinforcements, construction and dredging so that habitats and biocoenoses are no longer in a natural state (Chap. 1). The present ecological status should be improved by the restoration of morphologically degraded shore sections. This report concisely summarises the basics of, and new approaches to, lake shore restoration, and gives an overview of experience to date in Germany (DE), Austria (AT), Switzerland (CH) and eastern France.In order to perform restoration works in a target-oriented way, a conceptual model (reference) of the nature (Chap. 2, 4.1) and the specific degradations (Chap. 3) of a given shore section are required. In practice, the means by which restoration works are carried out are determined by a legal framework (i. e. laws regarding nature conservation, water protection and flood prevention) which varies between the countries concerned (DE, AT and CH) (Chap. 4.2). The planning process should support a check-up and assessment, so that even after a number of years, comparisons can be made between the original and present state. This report gives a detailed description of such an improved planning process, from a definition of planning and effective perimeters and the shore-type specific reference, through to the survey of the initial state, the analysis of ecological deficits and the restoration potential. The report also includes suggestions regarding implementation planning, ecological surveillance of construction, and management plans (Chap. 4.3). The operation methods used to date include extensification of uses and management of visitor flows, prevention of bank erosion, reduction of silting and accumulation of drifting matter, planting and establishment of wetland plants, and the re-shaping of a near-natural shore profile (Chap. 5). Special approaches are needed in the case of artificial and heavily modified standing water bodies (e. g. reservoirs, open pit lakes, navigation canals) (Chap. 5.6).The advantages associated with an accompanying ecological surveillance (i. e. preliminary investigation, ecological surveillance of the works, function checking) have often been neglected, although it is helpful in optimising efficiency and effectiveness of shore restoration projects (e. g. introduction of target species, re-establishing ecological functions) (Chap. 6). To this end, a number of rules must be abided by, which also contain elements of sampling planning, statistical testing of results, and quality assurance.The final chapter summarises the experience gained so far in relation to lake shore restoration projects in DE, AT, CH, and eastern France. Unfortunately, the transboundary exchange of concepts and methods has not been very intense (Chap. 7). A glossary of terms and a detailed list of literature, laws and standards round the report off.