Interreg Projekt ALFFA

Holistic (cross-scale) analysis of the influencing factors and their effect on the fish fauna in the inner alpine region.

infoboxWith the increasing use of our cultural landscape, the water systems are also subject to an increasing influence by various anthropogenic measures. Most water bodies are subject to multiple pressures due to combinations of interventions. A resulting multiplication effect can lead to dramatic changes in aquatic habitats and their organism communities. Fish are used as bioindicators for water systems throughout Europe. Reliable statements about the condition of a water body can be made via the existing species spectrum, the abundance and dominance ratios and the population structure of the individual species.
The sometimes dramatic changes of the fish fauna in Tyrol and South Tyrol range from the local decline of individual populations to the current threat to the stocks and in individual cases even to the disappearance of species. In contrast to most previous studies, the ALFFA project does not aim to identify individual causative factors, but rather the combination of as many influences as possible on a large scale and make them recognizable with the help of geostatistical and cross-scale models. The knowledge gained from this should be an important aid in future decisions regarding watercourse and environmental management.

In the currently ongoing watercourse status surveys in Austria and Italy, the changes caused by anthropogenic influences are clearly emerging. The main causes of these impairments are assumed to be morphological (e.g. watercourse interruptions) and hydrological (e.g. hydropeaking, residual water). Investigations concerning the influence of the surrounding area have so far been limited to banks, embankments and at most to the valley floor of the water body. In the present project, the large-scale influence of the surrounding area is to be considered in particular. According to initial indications, the anthropogenic influences in the catchment area are likely to have a much greater impact on fish fauna and aquatic ecology than previously assumed. New to the assessment concept is the combination of individual factors (hydrology, morphology, management, biogenic pressures, and surrounding environment). Previous approaches usually considered only individual factors or a few combinations of factors, and thus often failed to provide satisfactory explanations with respect to the loss of quality of water systems.
The aim is to achieve a better understanding of the interactions between the ecosystem water body and the surrounding environment. To achieve this goal, existing data (landscape mapping) will be used or, where necessary, new data will be collected. For an effective alignment of the data, a transboundary harmonization of the survey methods is indispensable (e.g. with regard to electrofishing), which will also be of great benefit for future surveys. The joint evaluation of all influencing factors (including in-water impairments) will create a model to explain the fish fauna. A better understanding of the different influences on the fish fauna and thus also on the quality of our water bodies should have a positive impact on future environmental and water body management.
The strength of this project lies in the inter- and transdisciplinary cooperation of qualified project partners from different fields (university and research institution, public administration, public law institutions and economy), the use and linking of institutionally already existing data and the associated holistic approach. This approach makes it possible for the first time to create a comprehensive picture of possible factors influencing water bodies and fish fauna, whereas previous European studies each covered different partial aspects. This comprehensive analysis, taking into account all major influencing factors, allows a weighing of the different influencing factors and a better evaluation of the different parameters, which was not possible in the previous individual studies.
In the North and South American region, work is already being done on and after holistic approaches with regard to fish fauna. Another innovation is the inclusion of endocrine disruptors (hormone pollution from sewage treatment plants), whose potentially very damaging effects have only recently been recognized. By selecting the areas to be investigated, a wide variety of geomorphological, climatic and land use factors are taken into account. In order to obtain as holistic a picture as possible, the focus will not be on individual species relevant to fisheries, but rather the total fish population will be surveyed and evaluated. The results of this project will therefore provide an important basis for further decisions regarding water protection. In addition, the results of this project can make a significant contribution to identifying the causes of the Europe-wide declining trend in freshwater fish fauna.

Members of this working group

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