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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 422-423 (2000), S. 85-97 
    ISSN: 1573-5117
    Keywords: ecological integrity ; running waters ; fish ecology ; extended serial discontinuity concept ; connectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Current ecological theories and concepts describe running waters as four-dimensional systems, their longitudinal, lateral and vertical linkages, interactions and exchange processes varying over time and over different scales. According to Ward & Stanford's (1983) extended serial discontinuity concept (ESDC), along a three-reach river, model the relative strength of the longitudinal pathways is highest in the constrained headwaters, vertical interactions reach their maximum in the braided middle course and lateral connectivity plays the major role in alluvial floodplain rivers. The present paper examines the general tenets of the ESDC from a fundamental fish ecology perspective. Specifically, it focuses on the degree to which the spatial/temporal connectivity requirements of fish communities or key fish species along a schematic longitudinal river course are compatible with the underlying principles of the ESDC and whether these requirements provide basic criteria for assessing the ecological integrity of running waters. From the fish ecological perspective, the examples provided here demonstrate a principle agreement with the concept of the four-dimensional nature of running waters, whose key functional and structural elements are spatial/temporal fluvial dynamics, disturbances, connectivity, succession and ecotones. Fish are particularly useful indicators of the temporally variable connectivities on the full range of scales at the three spatial dimensions. As far as the habitat requirements of typical species/developmental stages are concerned, two major modifications of the ESDC are needed. In constrained headwaters, in addition to longitudinal connectivity, the crucial importance of the vertical pathway river/bed sediments for reproduction must be emphasized. Also, in addition to lateral connectivity, longitudinal connectivity remains a vital basis for potamal fish communities in alluvial braided and meandering zones.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 386 (1998), S. 195-202 
    ISSN: 1573-5117
    Keywords: habitat assessment ; abiotic criteria ; physical environment ; ecological integrity ; habitat integrity ; habitat quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Based upon well-known relations between abiotic and biotic components of river systems, habitat assessment can serve as an indirect procedure to evaluate the ecological integrity by demonstrating the degree of man-induced alterations of the physical environment. Detailed habitat analysis has been an integral part of aut- or synecological investigations in aquatic environments. In many countries, however, the assessment of the physical environment on a larger spatial scale has become a regular part of watershed management programmes. A primary methodological aspect of large-scale habitat assessment is the selection and definition of evaluation criteria specifically designed to identify key functions and processes of intact river systems. Therefore, special emphasis has to be given to integrative parameters, that reflect the spatial and temporal dynamics of running waters as well as the interactions between rivers and their wetlands. Four groups of evaluation criteria are discussed within the framework of their relevance for aquatic biocoenoses and their validity to identify severe human impacts on running water ecosystems: (1) discharge regime; (2) morphological character; (3) lateral connectivity and (4) longitudinal corridor.
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  • 3
    ISSN: 1573-5117
    Keywords: assessment ; ecological integrity ; concept ; Water Framework Directive
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 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.
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  • 4
    ISSN: 1573-5117
    Keywords: water quality ; assessment criteria ; biological hierarchy ; reference conditions ; MuLFA ; Austria ; Europe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We propose a multi-level concept for fish-based assessment (MuLFA) of the ecological integrity of running waters. This concept is designed for large-scale monitoring programmes such as required for the proposed Water Framework Directive of the EU. Out of five different biological organisation levels (fauna, community, guild, population and individual), we propose seven criteria: River-type-specific species, species with self-sustaining populations, fish region, number of guilds, guild composition, population size and population age structure. The principle of the MuLFA is based on assessing the deviation from undisturbed reference conditions. Reference conditions have to be compiled for every distinct river type using historical fish and abiotic data, present river-type-specific reference sites and reference models. The final assessment procedure is done by comparing the assessment reach with the reference conditions using a 5-tiered normative scheme and assigning that reach to the level of highest coincidence. The benefit of the MuLFA is its potential for consistent sensitivity to low- and high-dose human alterations, and due to its general character, its adaptability to all river types.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 303 (1995), S. 183-194 
    ISSN: 1573-5117
    Keywords: river restoration ; revitalization ; river management ; ecological improvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An analysis of restoration projects carried out both in Austria and abroad shows that most projects are limited to design measures within the river bed with the general intention to increase habitat diversity. The various measures are not based on the type-specific characteristics of the river and thus there is a danger of creating uniform restoration stretches, independent of the specific landscape area, river morphology, discharge regime or site specific biocoenoses. Such proceeding lacks in considering a comprehensive improvement of ecological functioning of the whole river-system. To meet those demands a type-specific guiding view (‘Leitbild’) has to be developed based on the pristine river conditions. The comparison of the river pattern including the characteristic features of its unmodified state with the actual situation leads to a comprehensive set of measures. The essential goals of such management-concepts are the integrity of the river habitat, self-regulation and self-regeneration, the preservation of intact resources, as well as the possibility to experience the uniqueness, diversity and beauty of natural river landscapes.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 303 (1995), S. 195-206 
    ISSN: 1573-5117
    Keywords: river restoration ; instream structures ; land/water ecotone ; fish fauna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Investigations of fifteen sections of seven Austrian epipotamal (barbel region) streams between 1981 and 1984 demonstrate the impact of instream river bed structures on fish communities. Reduced spatial heterogeneity due to river straightening resulted in decreasing species number, diversity, stock density and biomass. Reincreased variability of the river bed in the frame of a subsequent restructuring project improved all community-specific values significantly within a 3-year investigation period (1988–1990). Besides the regained habitat variability in form of riffle pool sequences and other instream structures, the newly created riparian zones obviously provided important niches, e.g. as refuge areas during flooding and as nursery grounds for fish fry. The positive effects of the recreated land/water ecotone are discussed with respect to river restoration projects.
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  • 7
  • 8
    Publication Date: 1995-04-01
    Print ISSN: 0018-8158
    Electronic ISSN: 1573-5117
    Topics: Biology
    Published by Springer
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  • 9
    Publication Date: 1995-04-01
    Print ISSN: 0018-8158
    Electronic ISSN: 1573-5117
    Topics: Biology
    Published by Springer
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