Andreas Chovanec

The Austrian way of assessing the ecological integrity of running waters: a contribution to the EU Water Framework Directive

The term ‘Oekologische Funktionsfaehigkeit’, synonymously used as ecological integrity, has become a pivotal word within both Austrian water management and limnological research. Incorporated in the most important laws concerning water management issues, the term ecological integrity reflects the necessity of considering water bodies as ecological systems. Although ecological integrity of running waters is and must remain a holistic concept, the current Austrian methodology aims at assessing it by investigating a number of key components: hydromorphological aspects (particularly habitat structures, flow regime, connectivity), physico-chemical parameters, macroinvertebrate and fish assemblages, biological water quality assessment and ecotoxicological evaluations. The classification is based on the assessment of these individual criteria by means of a comparison between a river-type-specific reference state and the current conditions. This approach, which has been laid down in the Austrian Standard M 6232 ‘Guidelines for the ecological study and assessment of rivers’, also meets the general requirements of the classification of the ecological status of running waters discussed in the EU Water Framework Directive. Besides describing the Austrian way of assessing the ecological integrity of running waters, some nation-wide programmes concerning water quality, habitat assessment, and river typology are briefly presented.

Rehabilitation of a Heavily Modified River Section of the Danube in Vienna (Austria): Biological Assessment of Landscape Linkages on Different Scales

The ecological condition of the Danube section in Vienna (Austria) has been greatly impaired by urban development, regulation, channel straightening and the construction of a hydroelectric power plant. In 1997, the shoreline of the Danube in this area was restructured by artificial side channels, coves, gravel banks, pools and temporary waters. A monitoring programme has been established focusing on the investigation of the functional integrity of these inshore structures: first results show that the sites isolated from the Danube serve as stepping stone biotopes for dragonflies and amphibians. Particularly amphibians are suitable indicators of the ecological functioning of riparian migration linkages on a (macro-) habitat scale. Rheophilic fish species (e.g. Chondrostoma nasus) colonise side channels connected with the Danube and indicate a longitudinal connectivity on a landscape scale. The role of these structures within an urban greenway is discussed.

Man-made wetlands in urban recreational areas ― a habitat for endangered species

Abstract A man-made pond, created in 1989/1990 on the Donauinsel (‘Danube Island’) in Vienna, called Tritonwasser, is described. The main items of discussion are as follows. Planning, design and construction of the pond—the pond was planned and designed according to the ecological requirements of amphibians and dragonflies, which were primarily met by a structural diversification of the shorelines and the near surroundings of the pond. Cultivation measures and control of the flow of visitors—special measures have been taken to minimise disturbances and damages on account of leisure activities of the visitors of the Donauinsel to guarantee a development as undisturbed as possible of the aquatic habitat. Efficiency control by bioindicators—the success of the project can only be assessed by regular follow-up investigations. The colonisation of the Tritonwasser by amphibians and dragonflies has been investigated for a 3 year period (1990–1992) following construction. From the number of species which colonised the Tritonwasser it can be concluded that by constructing (and successfully managing) artificial wetlands, refuges for endangered species can be created, even in highly frequented urban areas.

Chapter 18 Fish as bioindicators

Abstract In this article, the role of fish as bioindicators is discussed. The comprehensive knowledge of taxonomy, habitat requirements, and physiology of fish is a key prerequisite of using fish as indicators. No other aquatic organism is suitable for the application of so many different methods which allow the evaluation of the severity of toxic impacts by determining the accumulation of toxicants in tissues, by using histological and haematological approaches or by detecting morphological anomalies. Due to its complex habitat requirements the fish fauna is a crucial indicator of the ecological integrity of aquatic systems at different scales, from micro- habitat to catchment. The fitness of fish species both at the individual level (e.g. growth performance) and at population level (e.g. population structure) is determined by the connectivity of different habitat elements in a broad spatial-temporal context. Thus bioindication using fish represents a good monitoring tool especially with regard to both pollution aspects and to river engineering, e.g. river restoration and management.

Heavy metals and pesticides in anuran spawn and tadpoles, water, and sediment

High concentrations of metals (cadmium, copper, lead, and zinc) and of lindane were measured in the sediment and in the spawn and tadpoles of Bufo bufo, Rana dalmatina, and Rana ridibunda from two Austrian locations. Residues in spawn suggest maternal transfer. Increase of the metal concentrations from spawn to advanced tadpole stage is explained by the larval microphaguous feeding habits which cause high exposition of the tadpoles to substances concentrating in sediments and suspended particles. Metal and pesticide concentrations in spawn and tadpoles are toxic to various other aquatic organisms and are furthermore considered to be potentially hazardous to the anurans themselves. The results are conform with world‐wide observations of contamination of anuran larvae with heavy metals, and prove the significance of non‐point source chemical exposure due to allochthonous toxicant input by wind load and precipitation.

River monitoring and water quality assessment in Austria

Since 1991, a new water quality monitoring programme for running waters has been established in Austria. The present paper shortly describes the legal and administrative framework of the project and the design of the monitoring network. Results of the first investigation period for the parameters BOD, NH4–N, AOX, and atrazine are also presented.

Sediment analysis as a method of monitoring industrial emissions

A number of investigations of river pollution in Austria are reported. Analysis of wastewater and river water was supplemented by investigations of sediments to characterize the influence of the different emission sources on the aquatic ecosystems. Examples of sediment investigations as tools for environmental monitoring are presented and the advantages of these methods are discussed.

Pesticides in the aquatic environment ‐ experiences from Austrian monitoring programmes

The present paper deals with the impact of pesticides on water quality in Austria. Results of different monitoring programmes and surveys concerning the contamination of groundwater and running waters are provided; various aspects of sediment analyses and bioindication are also discussed. The evaluation of the data reveals a rather serious situation particularly in the eastern parts of the country intensively used by agricultural activities. The substances most often detected are triazines and lindane. Legal measures and key figures on the Austrian agriculture are also presented.