摘要:

AbstractIf fresh waters are to be managed sustainably, and the potential to resolve conflicts of use realised, the general public must be more involved in their management. Participation in water management in England and Wales occurs at three levels, formal consultation, public involvement or actual direct participation by the public. Formal consultations often leave the public in the role of the ‘objector’ and ignore the ‘silent majority’, focusing on the more vociferous minority of the population. Public involvement is less formal and can take a variety of forms. Although not allowing the public to be directly involved in the decision‐making processes, it provides the public with the opportunity to comment upon plans for river works or the re‐development of a river location, or to indicate what they want from the rivers that flow through their own local area and which they use for recreation and amenity. True participation is where the public are actively involved in the decision‐making processes. Public participation at all three levels provides environmental education, however, personal experience promotes a greater environmental awareness and understanding by the public.There have been a number of educational initiatives aimed at schools in the United Kingdom which incorporate participation and education. Care of, and learning about, the natural environment is part of Key Stage 2 of the National Curriculum taught in all schools for eight‐ to twelve‐year‐old children.This paper reflects upon approaches to public participation and environmental education in the United Kingdom and provides examples of specific projects and campaigns involving both formal organizations and

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00042.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractOpen‐cast lignite mining has exposed formerly anaerobic layers to the air. Pyrite and marcasite are oxidized to sulfuric acid and iron sulfate, which later hydrolyses to iron hydroxide. When the pit is refilled with groundwater, its pH is 2–3. These geogenically acidified mining lakes are brown, with high iron content. Biological conditions differ greatly from those in most natural lakes and resemble those in sulfur‐acidic lakes impaired by acid rain. The usability of these fish‐free lakes is also restricted for recreational purposes.Neutralization with lime is expensive. The iron‐buffered water has a high base buffering capacity stabilizing at pH 2–4. The complex of potential measures for neutralization comprises: the revegetation of the waste heaps, the hydrological regime and coupled transport processes, the selection of suitable filling water and in‐lake technologies. Desulfurication takes place with sulfidic binding of iron and natural neutralization under locally anaerobic conditions in the reclaimed overburden heaps, in the deep water of mining lakes, in macrophyte stands and in the sediments.Anaerobic conditions should be established within the lakes during stratification periods: in the hypolimnion of eutrophic or the monimolimnion of meromictic lakes. Acidic lakes often are not sufficiently productive to achieve deep‐water oxygen depletion. Measures to increase the stability of stratification may be necessary, for example by installation of barriers to establish an environment suitable for biological neutralization. Carbon sources for microbial desulfurication may be added artificially or autochthonically produced by primary producers. Therefore, a controlled eutrophication may be useful in the initial filling stages of acid

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00043.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractChenderoh Reservoir on the Perak River, Malaysia, is a small tropical reservoir. Being a flow‐through reservoir, the water‐level management and retention time of the reservoir are dependent on the water management schemes of the three upper reservoirs. The fish biodiversity in the reservoir is relatively higher than that shown by areas downstream of the reservoir. Most species found in the downstream area are‘r’strategists in contrast to those in the reservoir where‘K’strategist species are more abundant. Biodiversity is higher in the reservoir possibly due to the higher number of niches available through the inundation of the shoreline and the creation of various coves and bays. There is, however, a reduction in biodiversity in the reservoir over time. This reduction could be due to environmental perturbation caused by land‐use activities along the shoreline of the reservoir. Although the fish standing stock is relatively low, small artisanal fisheries exist in the reservoir supporting the local communities. In order to maintain sustainability of the fisheries, the local fishers have been practising community‐based management since the early 1980s and prior to the official enactment of the Perak State Fisheries Riverine Rules. In general, because of the sensitivity of tropical reservoirs to environmental perturbation as well as limited living space created by the existence of a permanent thermocline, tropical reservoirs should be properly managed so as to protect and maintain their biodiversity and sustainability through wise use of the aq

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00044.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe growth and production of the annual floating‐leaved water chestnut (Trapa natans) were studied during summer 1993 at three sites at Lago di Candia (Northern Italy). These sites were subjected to different levels of harvesting from 1986 to 1992. Site USD was the unharvested control site; site 30S was harvested in alternate years (1987, 1989 and 1991); site 30D was harvested every year from 1986 onwards (except 1989) and moreover was sown during 1990, 1991 and 1992 with 8, 4 and 4 seeds/m2, respectively. Despite differences in seed density in the sediment, reflecting different harvesting and sowing practices, neither the biomass of water chestnut nor the fruit production were statistically different in the three sites although the production of buds, flowers and fertilized ovaries was higher at site 30D. In this site, where the plant density was four times lower, water chestnut increased the number of rosettes per plant two to fourfold. This productivity increased the population's invasive capacity. In Lago di Candia, water chestnut grows to 3 m in depth and it competes successfully with hornwort (Ceratophyllum demersum) in the littoral zon

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00045.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractLong‐term eutrophication data collected by the South Florida Water Management District at eight stations in the pelagic region of Lake Okeechobee since 1980 were combined with those from littoral region stations collected since 1986. These data were supplemented by those collected by the University of Florida in conjunction with the Lake Okeechobee Ecosystem Study. Generalized additive models (GAM) were fit to the chlorophyllaresponse for each of five previously documented‘ecological zones’, each using the same predictor variables for comparison between zones. Significant nonlinear increasing relationships between log10TP and log10chlorophyllawere found for littoral and near littoral regions of the lake, which change to decreasing at certain (high) levels of log10TP. This change to a decreasing function suggests light limitation associated with high TP levels due to particle resuspension. The error distribution of the GAM compare favourably to those of linear models. The relationship of the chlorophyllaresponse to the predictors used in the GAM appear similar for littoral and near littoral regions, as they do for north pelagic and central pelagic ecological zones, with intermediate shapes of these functions found in the transition zone between these two g

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00046.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractLake Victoria has recently undergone immense biological changes. These have led to the extinction of indigenous ecosystems and biota. Decrease in biodiversity has been characterized by mass extinction of cichlid fishes and benthic macroinvertebrates, especially insects. Increasing pollution and/or eutrophication has resulted in the deterioration of water quality and an increase in water‐borne diseases. Infestation of the water hyacinth (Eichhornia crassipes), which occurred recently, is the latest problem. These problems suggest several responses. A genebank of the remaining fish species should be created. Cage and/or open sea farming of the endangered fishes in Lake Victoria is a viable option in captive breeding of the remaining cichlids. Rehabilitating sewage pumping plants and extending treatment to unsewered urban areas would control organic pollution. Filtration systems based on macrophytes could be used in small urban centres to decrease pollution. Special attention to the taxonomy of the benthic group of insects is needed since undescribed species are being los

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00047.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractMexico, with its unique northwest‐southeast horn‐like shape, attains its largest continental area toward the northwest. It spans more than 15° of latitude and longitude. Two‐thirds of its territory lie 800 m or more above sea‐level. The relief, dominated by mountains, is rugged. Climate is varied and includes arid, steppe‐like, temperate and tropical lands, with a general trend of increasing aridity north of the Trans‐Mexican Volcanic Belt. Such a heterogeneous physiographic‐climatic scenario leads to a wide diversity of epicontinental aquatic resources, with a general trend of increasing water availability south of the Trans‐Mexican Volcanic Belt. Nonetheless, Mexico scarcely holds 0.1% of the worlds’inland aquatic resources. In order to characterize, plan, and manage aquatic resources of so extensive an area, it is important to undertake a limnological regionalization. Considering the hydraulic, climatic, geographical and geological attributes of Mexico, a lake inventory and regionalization is provided to improve knowledge of the extent of Mexican limn

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00048.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractLimnological investigations of the river reservoir Mavčiče (the Sava River, Slovenia) were carried out between May and October at regular three‐week intervals. The scope of our investigation was to determine physico‐chemical parameters, species composition, abundance and changes in the plankton community during summer stratification. The dominant taxa of phytoplankton were Chlorophyceae and Dinophyceae, and less so Cyanophyceae and Bacillariophyceae, while Rotatoria and less so Ciliata, Heliozoa and Cladocera were common zooplankton taxa. Eutrophication is in progress and primarily results from the high input of municipal and industrial wastewater from the nearest town. The concentration of total phosphorus and nitrates regulates the extent of primary production in the reservoir. The result is oxygen depletion in the hypolimnetic layer and anoxic conditions in the sedi

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00049.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIn Japan, there was an unusually cool and rainy summer in 1993, and an unusually hot and dry summer in 1994. We investigated chemical species in the waters of Lake Biwa during these two years. Samples were collected vertically from stations off Omimaiko in the mesotrophic northern basin and at a dredged area in the eutrophic southern basin, and surface water samples were also collected from three other stations at about one month intervals. We also studied chemical species in precipitation collected at Otsu, on the southeast shore of the southern basin, and sediment cores collected from the southern basin. The features of the lake water were very dependent on the summer climate. In 1993, abundant rain and weak thermal stratification supported high nutrient concentrations in the epilimnion. In 1994, nutrients were depleted and a high transparency and low concentration of chlorophyll a were observed in the epilimnion of the northern basin. This is because the supply of nutrients was limited owing to little rain and a well‐developed thermocline. However, a great deal of dissolved reactive phosphorus (DRP) occurred until late August in the southern basin. Local anoxic conditions were extensively developed in 1994, since a large amount of macroalgae grew and regressed in the southern basin owing to a high water temperature (30°C) and decline in the water‐level. Presumably DRP was desorbed from ferromanganese oxides that were reduced in the anoxic sediments and the DRP found its way into the lake water. Although it has been reported that the concentration of phosphorus in the lake water had not significantly increased in the last two decades, phosphorus which had steadily accumulated in the sediments had a crucial effect on the quality of the lake w

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00050.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe construction of Kariba dam resulted in the development of an unplanned town, Kariba. The sanitary services of this town originated from provisional arrangements. The town now has a population of about 27 000 inhabitants. Tourism, both local and international, is one of the major sources of employment. This study has revealed the presence of high levels of coliform bacteria in the inshore waters of the urban environment. The main sources of these bacteria are poorly managed private and municipal wastewater disposal systems. The private sector contribution emanates mainly from the lake‐shore tourist resorts. Although there are wastewater management defects indicated in the study, the main cause of the problem is identified as the immaturity of governance in which state employees can be in dereliction of duty with impunit

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY