Monster Seminar JAM - Fish Based Assessment Methods and Application to River Restoration in Austria and Europe
Dr. Stefan Schmutz
Institute of Hydrobiology and Aquatic Ecosystem Management, University for Natural Resources and Applied Life Sciences
This presentation summarises (1) methodological approaches to assess the ecological status of running waters based on fish and (2) how these methods are used for evaluations of river restoration projects.
Main focus is given to different methodologies used to assess restoration success. The key element is to elucidate the role of spatial resolution in the evaluation process encompassing micro, meso and macro scales. Within reviewed projects mainly fish is used as biological indicator. The results show that at the micro and meso scale a clear response of the fish fauna to restoration activities can be observed using case-study-specific criteria. However, most restoration studies still fail in demonstrating restoration success at larger, e.g. (sub)catchment level. This is in contradiction to the water legislation of European Union (Water Framework Directive - WFD) requiring biological assessment of entire river catchments in order to achieve the directives objectives, the good ecological status. Therefore standardised and highly aggregated biological indices are needed for large scale evaluations compliant to the WFD.
One contribution to standardised large scale assessment is the European FAME project, where we developed different methods for assessing the ecological status of European rivers. Method development of the FAME project (http://fame.boku.ac.at) is based on data from 12 countries, 17 ecoregions, 2700 rivers and some 15000 samples. Two different approaches were tested: a site-specific approach resulted in the European Fish Index (EFI) and a spatially based type-specific approach based on European Fish Types (EFT). (1) The EFI is the first assessment method applicable across Europe. The method accounts for environmental variability of rivers by using environmental variables (e.g. altitude) for predicting reference fish communities (regression models). Reference conditions are described by 10 metrics selected from a set of 250 potential metrics. The basic principle is to examine the deviation of observed metric values from the reference metrics and to transform this difference into the probability of representing the reference status for any given site. The index is the average of the 10 metrics. (2) For the spatially based approach sites with homogeneous species composition were clustered into fish types resulting in 15 EFT. For each of the EFT a multi-linear model (Discriminant Analyses) was developed to distinguish between 5 levels of degradation using a set of type-specific metrics. Comparison among FAME methods and with existing regional methods demonstrated that the EFI is about as precise as other methods. The FAME methods are able to discriminate between unimpacted and impacted conditions in about 80 % (EFI) to 90 % (EFT) of the cases when comparing the indices with existing pressures.
Date and Time:
October 20, 2005,
11:00 am - 12:30 pm