摘要:

AbstractThe Canada–United States Great Lakes Water Quality Agreement calls for the use of a systematic and comprehensive ecosystem approach (i.e. accounting for interrelationships among water, air, land, and all living things, including humans, and involving all user groups in comprehensive management) in water resource planning, research, and management. This Agreement further calls for the public to be consulted in all management actions. Remedial action plans (RAP) are being developed and implemented to restore uses in degraded areas of the Great Lakes and lakewide management plans (LaMP) are being developed and implemented to restore uses in open lake waters. These planning processes represent practical application of ecosystem approach theory. Lessons from practical experiences with Great Lakes RAP and LaMP include: an ecosystem approach can result in eliminating overlap and increasing efficiency; there can be positive effects from opening up decision‐making processes through meaningful public participation; priority should be placed on reaching agreement on problems and priorities; identification of key actions and delineation of sequencing, timeframe, and responsibilities is essential to ensure accountability; there is a need for a step‐wise approach to use restoration and demonstration of incremental progress; emphasis should be placed on planning cooperatively and sharing responsibilities for programme delivery; governments should provide resources to factilitate multi‐stakeholder decision‐making processes; spatial and temporal scale issues must be addressed; management actions should be treated as experiments; coupling of research and management has proven time and again to be cost‐ and ecosystem‐effective; and emphasis should be placed on measuring and celebrating progress for continuou

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00056.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe first International Conference on Conservation and Management of Lakes was held in Otsu, Japan, in 1984. Succeeding conferences were held in the USA, Hungary, China and Italy. Other global environmental activities include the Stockholm UN conference in 1972, the Nairobi Declaration in 1982 and the UN report on our common future in 1987. In 1992, the Earth Summit was held in Brazil and environmental restoration began on a global scale. The Rio declaration stressed that harmony with nature is important. Agenda 21 outlines an action plan for mankind, where not only the role of state and local government is described, but also that of non‐government organisations (NGO), industry, labour, scientists and farmers. In Japan, the Basic Environmental Law was enacted in 1993 in response to the Earth Summit; the Basic Environmental Plan was formulated in 1995. In the plan there are four keywords: circulation, coexistence, participation and international activities. Circulation means to create an economic social society based on circulation. Coexistence means to restore and to maintain an ecosystem, and to ensure coexistence between nature and humankind. Participation means that each entity cooperates and works actively for environmental preservation. International activities means to make the best use of experience, technology and capability in order to promote international cooperation. We are in the midst of a major movement towards global environmental preservation. We have a responsibility to pass on a healthy and beautiful Earth to our children, grandchildren and great‐grandchildren. However, environmental improvement is not an easy task; in particular, the improvement of the lake environment is lagging beh

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00057.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPakistan covers 79.1 million ha in which the area of water is estimated at 7.8 million ha and provides food and shelter to the local inhabitants as well as visiting and resident wildfowl. From early July to late September, monsoons reach into Pakistan and are of immense significance to the country's wildlife and agro‐based communities. However, a vast part of the country, mainly Baluchistan province, remains deprived of this rain but in winter seasonal rains and snow occur, particularly in Quetta, Zhoba and Pishin valleys. This rain and snow melt water provides a source of sustenance to the people of not only Baluchistan, but also Afghanistan. This water settles in a chain of lagoons in the Chagai desert, and provides much bird habitat. For centuries, Lake Zangi Nawar has been used by hundreds of thousand of birds and many local tribes. The people and governments have collectively made small dams so that this large source of water may be of help through seasonal agriculture and pasture management for their livestock, on which the people mainly depend. The lake is the sole source for raising the water‐table for the nearby villages who use this for drinking purposes. These Baluch tribes are barely literate, but with experience they have recognized that the lake and its valuable by‐products are of immense advantage. Thus, they carefully watch and guard the whole area. The study considers the available resources, the community response, and the development made by the visitors at Zangi Nawar. It also provides options and suggestions for long‐term sustainable management of the wetland and its re

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00058.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAbundance and diversity (number of taxa) of planktonic and epibenthic invertebrates were examined between October and December 1994 in a small shoreline marsh of southwestern Okanagan Lake, British Columbia, and compared to adjacent shoreline that was (i) slightly modified by human activity, and (ii) heavily modified by riprap placement. Planktonic and epibenthic invertebrate abundance and diversity was several‐fold higher in the shoreline marsh habitat, intermediate in the slightly modified shoreline habitat, and lowest in the riprap shoreline. A mid‐1930 survey of Okanagan Lake reported that only 9% of its shoreline had rooted aquatic vegetation, so historically the lakeshore marshes were scarce. Currently, only small vestiges of such habitat remain in a 42 km stretch of its southwestern shoreline where 80% of this length has been altered by various development activities: 41% by lakeshore housing and cottages, 27% by lakeshore road riprap, and 12% by parks, swimming beaches and other recreational developme

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00059.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractIndian Remote Sensing Satellite (IRS‐IA) LISS I and LISS II data were studied to delineate major lake environments along the east coast of Tamilnadu, India. IRS‐IA satellite data were useful in delineating the spatial extent of lacustrine water‐bodies, their probable origin and regional setting, and their influence on the local environment. A few water‐bodies (i.e. Pulicat, Kalveli and lakes along the Vedaranniyam coast) were selected for particular study. They are the result of marine transgression during the late Cretaceous, and form an integral part of neotectonic and land‐building activities of the area. This study explains the relationship between lakes and coastline configuration, and is significant in understanding the lake environment and its subsequent role in coastal zone

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDuring the first year of a 4 year pond experiment, the conditions under which fish manipulation has any effect on lower trophic levels and water clarity was studied. Cyprinid fish of mature age classes (3+‐ 4+) were introduced into each of three experimental ponds with an area of 0.3 ha (average depth ∼1.7 m), while a fourth pond was left free of fish. Bream (Abramis bramaL.), white bream (Blicca bjoerknaL.) and roach (Rutilus rutilusL.) made up 75% of the total cyprinid biomass, with wild carp (Cyprinus carpioL.) as the remaining 25%. The introduced fish spawned successfully. Different fish stocks (100, 300 and 500 kg ha−1) were simulated in each of the three experimental ponds. The high (above 300 kg ha−1) planktivorous and benthivorous fish stocks resulted in several qualitative and quantitative alterations to the food chain structure in these simulation pond experiments. These alterations must largely be assigned to changes caused by both the zooplanktivorous and benthivorous nature of the stocked fish populations. At the higher levels of fish biomass, Secchi depth was influenced significantly by chlorophyllaconcentration. Most of the variance in suspended solids concentration could be explained by the biomass ratio of the mature benthivorous fish. There was a clear shift in algal cell size in the ponds with the higher fish stocks; ponds with more fish had large cells later in the summer. The relative influence of young cyprinid fish on crustacean species composition and biomass, and mature populations on benthic fauna abundance and biomass, was significantly greater at higher (300‐500 kg ha−1) fish

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00061.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe growth and nitrogen fixation ofAzolla filiculoidescultured in polluted pond water and two types of secondary effluent were investigated. The gradual decreases in the growth and acetylene reduction activity (ARA) of the plants in pond water were due mainly to a phosphorus deficiency. In the secondary effluent, ammonium was an important factor limiting growth and ARA.Azollaplants were screened for tolerance to ammonium ion on the basis of their growth on the medium with or without ammonium.Azolla niloticawas the most sensitive species of all, followed byA. rubra. Azolla pinnatavanpinnatawas the most tolerant one. Nutrient removal capacities by 10Azollastrains in batch culture were examined. The highest capacities and the growth were found in May for allAzollastrains. In August and December,Azollastrains showed poor growth and low nutrient removal capacities.

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThree core samples from Lake Biwa, Japan, were analysed for mercury (Hg) and other heavy metals (iron, manganese, zinc, copper, lead, nickel, chromium, cobalt). The concentration of Hg in the core samples investigated varied from 106 to 222 ng/g. The sedimentary records of the lake indicate that the anthropogenic input of Hg parallels the increasing intensity of cultural activities in the lake basin. The maximum anthropogenic input could be identified for Hg during the mid‐1960s. The geo‐chemical data of the lake sediments are used to evaluate the behaviour of Hg with other trace met

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractSixteen lakes in Estonia and five lakes in Finland were investigated during 1992–95, using mainly optical methods. A total of 14 expeditions were undertaken, but the number was different for each lake. Vertical profiles of solar irradiance (spectral and integral), temperature and dissolved oxygen in the water column were measured, and Secchi disk depths were determined. Chlorophyllaand suspended matter concentrations were determined in the laboratory from water samples. Spectrophotometrical processing of the water samples (unfiltered and filtered water) was carried out to describe the beam attenuation coefficient spectra and to determine the spectral influence of yellow substance in the water. Passive optical remote sensing measurements were made from on board a boat. The data obtained show a rather high variability in water characteristics, although the lakes investigated are situated in the same climatic region. Several lakes receive human impact, and this has led to a decrease in water transparency and an increase in eutrophication. Despite rather low values for attenuation depth in lakes, water quality can be estimated using optical remote sensing dat

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00064.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn outdoor enclosure experiment was carried out to study the effect of some selected pesticides on phytoplankton of Lake Omdalsvann, Norway. The experiment lasted 2 weeks during 1990 July/August). The pesticides tested were chlorosulfuron (herbicide), propiconazole (fungicide), dimethoate (insecticide) and glyphosate (herbicide). The pesticides were tested at three concentration levels (1 μg L−1, 10μg L−1and 100μg L−1) of their active ingredients. Samples for phytoplankton analysis were collected twice each week. The species richness differed greatly among the experimental bags. All treatments resulted in a significant (P<0.05) decrease in species number compared with the results of the control. At the same time, great differences did exist in algal biomass in response to different pesticides tested. The pattern of biomass deviation from control (positive or negative) and magnitude (significant or non‐significant, atP= 0.05) were mainly dependent on toxicant type, concentration and the exposure time. Shannon‐Wiener diversity indices ranged between 2.69 and 2.76. The index values decreased significantly at all pesticide treatments with lowest values usually recorded 2 days after adding the pesticides. The biomass of some natural algal taxa varied quite independently not only to the different pesticides but also to their concentrations; a finding which supports the concept of species‐dependent variation in algal sensitivity to chemicals.In situtoxicity testing seems to be a reliable protocol to generate more realistic data necessary for environmen

ISSN:1320-5331    

DOI:10.1111/j.1440-1770.1996.tb00065.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY