Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 10

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  land-water ecotone
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

From land-water ecotones to the concept of ecohydrology

100%
Fournier F.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 3
2

Planning approaches to mitigate adverse human impacts on land-water ecotones

86%
Kondolf G. M.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 flood control channels. These measures increase flood hazard downstream and result in loss of valuable riparian and aquatic habitats. Similarly, human settlements along river banks may be threatened by natural channel migration, leading to ill-conceived bank stabilization projects, which eliminate riparian habitat. Environmental planning strategies to minimize these impacts include reducing stormwater runoff through use of permeable pavement, infiltration galleries, and detention basins; ordinances protecting urban streams and riparian corridors (from development, filling, etc.); prohibitions or restrictions on development on floodplains; retention of vegetative buffer strips along stream channels; maintenance of continuity of riparian corridors for wildlife and human use; use of alternatives to traditional flood control strategies; and release of flushing flows to mimic effects of natural floods below reservoirs.
3

Fish and land-inland water ecotones - overview and synthesis

58%
Zalewski M., Schiemer F., Thorpe J.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 conservation. Land-water ecotones, if restored and managed in a sustainable way, can buffer and filter impacts on aquatic ecosystems due to catchment development, by moderating hydrological processes, improving water quality, and increasing spatial complexity of habitats. This way, fish resources can be safeguarded, restored and sustained. The programme of the 'Fish and Land-Inland Water Ecotones' (FLIWE) team has shown strong links between fish life histories and structures and processes in land-water ecotones. To be able to sustain freshwater fish populations a good understanding is needed of the biological linkages and pathways through land-water ecotones; of biogeochemistry; of modern techniques for habitat inventories; and of methods of habitat evaluation, planning and assessment of socio-economic feedback.
4

Fish and riparian ecotones - a hypothesis

58%
Zalewski M., Thorpe J. E., Naiman R. J.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 animals living in them. Riparian ecotones provide feeding places and shelter for fish, and are particularly important for their reproduction and earliest life-history stages. The complexity and biological importance of riparian ecotones depend on the extent to which the system is self-regulating, which depends in turn on geology, physiography, climate, vegetation, human activity and the age of the system. By changing riparian ecotone character, fish density can be regulated through controlling reproduction and recruitment, and energy flow through the food chain can be controlled for management of water quality.
5

Buffering role of land-water ecotones in the structuring of the fish community of the Sorraia system

58%
Coelho M. M., Pires A. M., Collares-Pereira M. J., Sousa E. C., Zalewski M.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 in the dominant vegetation). The variation in species abundance and distribution was correlated with physical factors. The results showed the preference of barbel and nase for riparian vegetation and greater depth and of roach for zones with macrophytic vegetation and high current velocity. Fish community of the Sorraia system does not exhibit a consistent pattern of temporal variation, what is usually observed in Southern streams of the Iberian Peninsula. This fact is probably related to the landscape disturbance.
6

Riparian ecotones, invertebrates and fish: life cycle timing and trophic base

58%
Bretschko G., Waidbacher H.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 improved the fish population immediately. Instream ecotones are equally important for the fish community in high order streams. Data are given for the 9th order Danube. The duration of floodplain inundation is unpredictable but generally short in the temperate climatic zone. Fish do not migrate far into the inundated terrestrial vegetation but stay in or near to the enlarged backwaters. In backwaters separated from the main stream, a potamal fish population survives in an otherwise rhithral stream section. Floodplain inundation is predictable and lasts over long periods in the tropics. Fish and invertebrates are adapted to use the vast resources of habitats and food by active migration into the inundated forests.
7

Economic aspects of agricultural area management and land-water ecotone conservation

58%
Petersen H. G.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 of property rights. Then it explains why sensible perspectives do exist, but are still not transformed into practical political measures or reforms.
8

Riparian ecotone as a key factor for stream restoration

58%
Zalewski M., Bis B., Frankiewicz P., Lapinska M., Puchalski W.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 as total protein, was significantly correlated with the amount of deposited CPOM and depended on stream order. Macroinvertebrate biomass was highest at an intermediate riparian ecotone complexity with an adequate supply of organic matter and incident light. Fish biomass followed the same trend, being lowest in heavily shaded areas and in open channels without riparian vegetation, but highest in ecotones of intermediate complexity. These results indicate that the riparian ecotone structure and the heterogeneity of the stream channel may regulate biodiversity, productivity and nutrient retention in the fluvial corridor.
9

The role of land-inland water ecotones in fish ecology on the basis of Russian research - a review

58%
Dgebuadze Y. Y.
International Journal of Ecohydrology and Hydrobiology
|
2001
|
tom 01
|
nr 1-2
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 scale ecotone studies of model and restored microhabitat of salmonid rivers; comparison of the ecotone patterns and fish abundance in two rivers differing by historical origin of their ichthyofauna; the analysis of the effect of cattle ranching on fish assemblages distribution, dynamics and productivity along a river course in the steppe zone; and the influence of periodically drying up lakes and ecotones on the dynamics of fish populations in the connected river system.
10

Effect of land-water ecotone on changes in heavy metal content in waters of agricultural area

58%
Szpakowska B., Karlik B., Goldyn H.
Polish Journal of Ecology
|
2003
|
tom 51
|
nr 2
Concentrations of zinc, cadmium and lead in ionic forms and in forms bound to humic substances isolated from ground and surface waters of drainage catchment were analysed. Higher total concentrations of examined metals were found in ground waters as opposed to surface waters. Particularly clear difference was observed in case of cadmium. Mean concentrations of cadmium in ground waters amounted to 0.92 μg l⁻¹, whereas in surface waters 0.50 μg l⁻¹. Similar tendency of higher heavy metals concentrations in ground waters as compared to surface waters was also observed in case of their ionic forms. Due to strong complexing properties organic matter can bind large amounts of metals and therefore influence bioavailability of the metals for aquatic organisms. Moreover the distribution of metals in aquatic environment depends on the presence of such biogeochemical barrier like belt of meadow, which can modify metals migration.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.