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The paper questions the usefulness of the static concept of the habitat as a templet in analyses of the influence of the riparian environment on the dynamics of riverine fish assemblages. Studies on the effect of deforestation on the water quality and invertebrate assemblages in upland streams in mid-Wales found that changes in the nature of the riparian habitat caused by logging had relatively few...
Land-inland water ecotones are environments of exceptional diversity, but are also highly vulnerable to impacts from human settlement. Settlement on floodplains and exacerbation of peak runoff from land-use changes have resulted in flood damage to human structures, leading in reaction to widespread efforts to control flooding through such measures as land drainage and construction of levees and artificial...
The roach preferred branches of spruce and juniper as artificial spawning substratum rather than pine and birch. Perch preferred birch over conifers. Thus altering the availability of spawning substrata in the littoral zone should be effective in controlling the density and structure of juvenile roach and perch communities in reservoirs. Density dependent processes affects the early life history of...
Riparian vegetation is a typical ecotone by its structural and functional position between the terrestial part of the watershed and the stream (Naiman, Decamps 1990). In consequence, the riparian zone forming an integrated component of stream ecosystems significantly determines the aquatic community. Macroinvertebrates are affected by defined variability of environmental factors. In streams under...
Increasing emphasis is being placed on managing aquatic resources on an integrated, basinwide basis. Traditional ground inventory methods are time-consuming and expensive, and are not easy to integrate over large areas. Remote sensing, combined with Geographic Information Systems (GIS) and Geographic Positioning System (GPS) technology, offers a more flexible, cost-effective method for gathering and...
To test the role of riparian ecotones in fish community dynamics three different sites along the Sorraia system, were selected. Each station has been under distinct anthropogenic pressure, and characterized by a mosaic of habitat conditions. Fish were collected by electrofishing from October 1991 to October 1993 using two distinct sampling scales, (50 m and small sectors defined according to discontinuities...
Natural riverine ecosystems are characterized by a high level of heterogeneity manifest across a range of spatio-temporal scales. Ecotonal habitats are both the result of and contributors to the spatio-temporal dynamics of riverine ecosystems. Natural disturbances play an important rôle in maintaining a diversity of ecotonal habitats. A typology of riverine ecotones is developed that provides an expansive...
Number of species (S), density (N) and standing crop (B) were investigated in 331 sites in the catchment of the Narew River, the biggest tributary of the Vistula, against 4 categories of riparian ecotone intensity in various-width rivers. All populations were first analyzed together, then within the scope of three most abundant ecological spawning groups. The image obtained is to some extent blurred...
The effect of riparian ecotone functional complexity and stream hydraulics on an upland river ecosystem has been analysed. The amount of nutrients retained by the bottom sediment was lowest on a sandy substrate and highest in wetland bays. A stream bed covered by Berula erecta had about three times higher nutrient retentive capacity than did a sandy substrate. The trophic potential of CPOM, measured...
The investigations were carried out in the lacustrine-fluvial system of the Lizhma river (the Ladoga lake basin) in its natural condition (until 1993) and during the exploitation of its trout complex. The authors show the water bodies to increase their content of biogenic elements at the expense of the organic form. They mark some changes in the structure of algoflora. The abundance of alkophylic...
Development culture, based on the dominance of man over nature and the built over the natural, continues to predominate. To take one example, the demands of an ever-increasing number of amateur fishermen are satisfied by financing the continuous re-stocking of rivers with juvenile or small-size fish while ignoring the extinction of native species, and the damage caused by the introduction of non-native...
This review summarises some results of investigation carried out by Russian scientists, concerning the influence of land/inland water ecotones on fish. The main objectives and hypotheses developing in the framework UNESCO MAB working group "Fish and land/inland ecotones" in Russia are: comparison of fish population in salmonid rivers affected or non-affected by lake-rivers ecotones; small...
Water (including increasing use relative to availability, and deteriorating quality) may be one of the most severe stresses on the exponentially growing human population in the next century. Problems are becoming increasingly complex and diverse and require more and more specific knowledge from both a technical and non-technical perspective. These complexities create the need to understand and comprehend...
Riparian ecotones are either within the bankfull lines (instream ecotones) or beyond (bank vegetation and floodplains). Instream ecotones (e.g. gravel bars) are most intimately and permanently interconnected with the stream system. The third order river Melk was channelized some decades ago with devastating effects on the fish fauna. The restoration of instream ecotones and of the riparian vegetation...
Today’s management of agricultural areas is hardly in accordance with actual economic and ecological goals. In view of the future risks for the global system a revolutionary change within our current land use systems is essential. The paper gives an example of a workable strategy for agricultural policy baded on the internalization of external burdens into a market price system as well as the expansion...
Authors present the hypothesis that freshwater fish diversity, recruitment and production depend greatly on riparian ecotones. These boundary environments are usually the most diverse elements of aquatic systems. Riparian ecotones moderate the transfer of energy and materials from the land, provide a high load of organic matter including invertebrate food, and moderate competition and predation among...
Water and land ecotones harbour complex interactions of hydrosphere, biosphere, atmosphere and lithosphere. Exchange processes at their interfaces involve multiple feedback mechanisms which to a large extent affect the overall conditions on earth. Hydrological processes affect ecotones and vice versa. The paper outlines briefly some of the effects and gives examples of ecotones in arid and urban environments.
The last free stretch of the River Paraná inside of Brazilian territory, about 230 km of the former 810 km, runs in a wide floodplain, which flood regime is controlled in part by upstream dams. Aim to evaluate the impacts of different levels of hydrological control on the regional fish diversity, nutritional condition, trophic categories proportion, reproduction and young abundance monthly sampling...
The dramatic depletion of diversity and standing crop of freshwater fish has been due mostly to degradation of their habitats and water quality. To halt and reverse this negative trend, a new approach is needed urgently toward sustainability of fish resources. The UNESCO MAB programme on the role of land-water ecotones has opened a new perspective towards solving problems in landscape management and...
In many rheophilic fish species, young stages with low swimming capacities are confined to lateral habitats protected from the main current. Among these lateral habitats, we defined „dead zones” as small bays with shallow water and slow water current caused by physical structures (obstacles or curves of the bank), but without a clear frontier with the main channel. Nevertheless, a study using two...
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