Challenges and objectives for geomorphology in U.K. river management     

Andrew Brookes 《地球表面变化过程与地形》1995,20(7):593-610

This paper reviews some of the challenges and objectives in the application of fluvial geomorphology to improved river management in the U.K. It describes the mechanisms by which geomorphology can be applied to solve problems, including the development of design guidance, policy, management approaches, procedures and training. While it is true that geomorphology is being used increasingly, there remain a number of challenges, such as the need to promote a more professional image and to develop appropriate standards. The scientific basis on which decisions relating to the water environment are made needs to be developed further. Perhaps some of the most significant challenges for fluvial geomorphology in U.K. river management during the next decade will concern river and floodplain restoration.  相似文献   

Chemistry and trophic evolution of Lake Lugano in relation to nutrient budget   总被引：1，自引：0，他引：1  

Alberto Barbieri  Rosario Mosello 《Aquatic Sciences - Research Across Boundaries》1992,54(3-4):219-237

Chemical studies performed in the last 50 years on the northern and southern basins of Lago di Lugano are reviewed and discussed in relation to the phosphorus and nitrogen loads from the drainage area.Both basins became eutrophic in the fifties as a consequence of the dense population and industrial activity in the drainage area; the effect of these was aggravated by the meromictic condition of the layer below 100 m in the northern basin.The reduction of phosphorus loads in progress since 1976 has resulted in a significant improvement in the chemical and biological condition of the southern basin and the upper 100 m of water in the northern basin. On the other hand, the balance between dissolved oxygen and reducing substances in the northern basin is shifting toward a decrease of the net oxygen concentration, partly as a consequence of the unusually dry conditions of the last three years.A reduction in phosphorus load down to 18 and 22 t a^–1 in the northern and southern basins respectively is still necessary in order to reduce the lake phosphorus concentration to 30–35 µg O l^–1.  相似文献   

Pelagic food web interactions and hypolimnetic oxygen depletion: Results from experimental enclosures and lakes     

Asit Mazumder  D. J. McQueen  W. D. Taylor  D. R. S. Lean 《Aquatic Sciences - Research Across Boundaries》1990,52(2):144-155

Large lakes enclosures were used to examine the influence of nutrient (P, N) enrichment and planktivorous fish (1 + yellow perch) predation on hypolimnetic oxygen depletion. Results were compared to similar data for lakes with high (Lake St. George) and low (Haynes Lake) abundances of planktivorous fish. In both the unfertilized and fertilized enclosures, fish predation on large cladocerans increased the biomasses of pico- and nanoplankton (0.2–20 µm), phytoplankton (chlorophyll a) and total phosphorus (TP), reduced sedimentation, water clarity, and hypolimnetic oxygen concentrations (AHO). Fertilized enclosures without fish had highest TP and sedimentation rates, but the AHO were low. The high planktivore lake had higher pico- and nanoplankton, higher chlorophyll a, reduced water clarity, and lower AHO than the low planktivore lake. Areal hypolimnetic oxygen depletion (AHOD) rates were strongly related with Secchi depth and plankton size-distribution (r ² = 0.77, and 0.79, respectively), but not as strongly with TP, chlorophyll a, and sedimentation rates (r ² = 0.25, 0.53, and 0.02, respectively). Such observations are useful in forming a generalized hypothesis that lakes with low planktivory and high water clarity have lower oxygen depletion because 1) plankton that are settling are larger and spend less time in the hypolimnetic water column before reaching the sediment, and therefore undergo less decomposition, and 2) the euphotic depth extends into the hypolimnion and production of oxygen can take place.  相似文献   

Implementing the WSSD decision of restoring marine ecosystems by 2015—scientific information support in the public domain     

Cornelia E. Nauen 《Marine Policy》2006

Among the relatively few decisions taken by heads of States and government at the World Summit on Sustainable Development (WSSD) in September 2002 in Johannesburg, South Africa, was the time-bound objective to restore degraded stocks to productive levels in its Plan of Implementation. The paper examines the evidence leading to this decision and the broadening of cognitive maps it implies. In particular, it documents how public archiving of research results and other knowledge sources particularly those accessible through the FishBase (www.fishbase.org) and Sea Around Us (www.seaaroundus.org) websites has been effective in enabling citizens in addition to specialist publics to counteract shifting baselines and monitor progress against the WSSD plan. The increased targeting and cost-effectiveness of research efforts and the social benefits of public research spending this implies militates for the extension of such approaches to other groups as an enabling mechanism for WSSD decisions on restoring marine ecosystems by 2015.  相似文献   

Trialling tools using hand-weeding,weed mat and artificial shading to control nuisance macrophyte growth at multiple scales in small agricultural waterways     

Kathryn E. Collins  Catherine M. Febria  Hayley S. Devlin  Kristy L. Hogsden  Helen J. Warburton  Brandon C. Goeller 《新西兰海洋与淡水研究杂志》2020,54(3):512-526

ABSTRACT

Introduced aquatic macrophytes can dominate small agricultural waterways in summer and autumn becoming a significant management problem. Excessive growth can clog waterways, causing drainage issues and reducing agricultural productivity while in-stream velocities are reduced and sedimentation increased. Consequently, water managers remove them by mechanical clearance, chemical spray and cutting which can be costly and have negative impacts on in-stream habitat and ecological health. We trialled three tools to reduce macrophytes: hand-weeding, weed mat and artificial shading, at a reach-scale (50?m) and larger-scale (200–400?m). Hand-weeding reduced cover in the short-term, however macrophytes recovered to pre-treatment levels within one season. Weed mat along the banks was effective at reducing emergent macrophytes, particularly Erythranthe guttata (monkey musk) and Nasturtium microphyllum (watercress). Weed mat lasted for several growing seasons and continued to be effective. Shading over the waterway using polythene markedly reduced submerged macrophytes indicating that heavy shading by riparian plantings could reduce submerged macrophytes in the longer-term. These results indicate that in the short-term, weed mat could be used to limit sprawling emergent macrophytes. In the longer-term, weed mat used in conjunction with riparian planting could provide shading so that macrophyte cover in these small waterways could be reduced and controlled.  相似文献   

Management measures and fishers' commitment to sustainable exploitation: a case study of Atlantic salmon fisheries in the Baltic Sea     

Haapasaari  P.; Michielsens  C. G. J.; Karjalainen  T. P.; Reinikainen  K.; Kuikka  S. 《ICES Journal of Marine Science》2007,64(4):825-833

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硬岩场地生态环境恢复技术探讨——以山东省东平县石灰石露天采场综合治理为例     

侯明允  王延岭  赵新卓 《华北地质》2009,32(2)

为了消除露天采石场残山存在的崩塌、滑坡等地质灾害隐患,减轻废弃土石对大气的污染,恢复原有的生态环境,本文以东平县石灰石露天采场综合治理为例,探讨了硬岩场地矿山地质环境恢复治理的综合方法,包括针对边坡进行放坡、对采坑进行推高垫低的工程施工方法,生态恢复物种的选取和培育方法等,为其它类似采石场地质环境的综合治理提供借鉴.  相似文献   

滦河口湿地黑嘴鸥原繁殖地恢复研究   总被引：2，自引：0，他引：2  

孙立汉  杜静  高士平  李东明  张茹春 《地理与地理信息科学》2005,21(3):84-87

滦河口湿地曾是世界四大黑嘴鸥繁殖地之一。近年来该地生态环境日益恶化,使黑嘴鸥失去了繁殖地。该文分析滦河口湿地环境因子变化和人为干扰对黑嘴鸥繁殖的影响,探讨恢复黑嘴鸥原繁殖地生态环境的目标和关键问题,为滦河口湿地恢复黑嘴鸥繁殖地以及有效保护黑嘴鸥种群提供理论依据。  相似文献   

浅谈河南省遂平县781废矿区治理与生态环境恢复工程     

吕志涛 《地质灾害与环境保护》2005,16(2):169-171

针对河南省遂平县781废矿基本自然环境、矿区破坏现状、对环境造成的危害进行了论述。提出具体的有针对性的治理措施。通过781废矿区的矿山治理,可控制废矿渣中的核辐射对人和牲畜、水质、植物等的危害,消除人们的恐惧心理,体现了党和政府“以人为本”的思想。  相似文献   

不同强度等级石漠化土地植被恢复技术初步研究——以贵州花江试验示范区查尔岩试验小区为例   总被引：28，自引：9，他引：19  

梅再美  王代懿  熊康宁  兰安军  陈永毕  孙建昌  余金勇 《中国岩溶》2004,23(3):253-258

分析了贵州花江试验示范区查尔岩试验小区中不同强度等级石漠化土地所表现出的缺土、缺水、植被覆盖度低、土地总体生产力水平低下等特征,提出了不同强度等级石漠化土地的植被恢复途径与对策,以及不同强度石漠化土地植被恢复过程中的主要造林植草技术。   相似文献