The role of the Yala swamp lakes in the conservation of Lake Victoria region haplochromine cichlids: Evidence from genetic and trophic ecology studies

Lake Kanyaboli, an isolated satellite lake of Lake Victoria, has been suggested as a potential refugium for haplochromine cichlids that have gone extinct in the main basin of Lake Victoria. Mitochondrial DNA (mtDNA) molecular markers, as well as feeding ecology studies, were employed in this study to re‐evaluate the evolutionary and ecological significance of six common Lake Kanyaboli haplochromines. The mtDNA marker revealed high genetic variability within four of the six haplochromine cichlids. Five haplotypes were discerned in Astatoreochromis alluaudi (n = 27), seven in Lipochromis maxillaris (n = 29), five in Astatotilapia nubila (n = 12) and 11 in the endangered Xystichromis phytophagus (n = 205). A haplotype genealogy suggests that Lake Kanyaboli harbours mtDNA haplotypes that could have been lost or not sampled in Lake Victoria, or could have arisen in situ. Lipochromis maxillaris appears to have undergone a recent demographic expansion. The pairwise F_STs indicated that only the comparison between X. phytophagus and A. nubila led to a non‐significant F_ST value. All other comparisons were significant at the 0.01 level, indicating the genetic distinctiveness of the haplochromines in the satellite lake. This could suggest that the lake harbours ‘pure’ relict populations of the haplochromines and therefore that Lake Kanyaboli can be considered a ‘genetic reservoir’. Gut content analysis of the six haplochromine species revealed that eight different food items were consumed. No single species fed exclusively on a single food item, but certain food items contributed higher proportions of the fish diet for each fish species. Resource partitioning therefore could be discerned within this haplochromine community. Thus, Lake Kanyaboli and similar satellite lakes provide an opportunity for conservation of both genetic and trophic diversity threatened by introduction of exotics in the Lake Victoria basin. Lake Kanyaboli should be recognized and conserved as important evolutionary significant units for Lake Victoria region haplochromine species.     

松辽流域水土保持信息管理系统建设

文中论述研制开发松辽流域水土保持信息管理系统的必要性,以全流域水土保持工作实际需要为依据,阐述了系统的模块组成与功能、特点、开发步骤、组织保障。     

The deep waters of land reform: land,water and conservation area claims in Limpopo Province,Olifants Basin,South Africa

Through investigating the reactions of commercial farmers to land and water reforms in the Trichardtsdal-Ofcolaco area, Limpopo Province, Olifants Basin, South Africa, from 1997 to 2006, it is shown that water claims are key to land redistribution processes, and that commercial farmers make strategic use of arguments for nature conservation and ecological stewardship to defend their claims to water. Given these observations, caution is warranted with respect to the implementation of land and water reforms as separate policy packages; it may be more effective to design water and conservation policies as an integral part of land reform programmes.     

高速公路弃土场变更相关水土保持问题浅析

本研究选取大庆至广州国家高速公路龙南里仁至杨村（赣粤界）段的弃土场为对象,对工程建设过程中设计与实际使用的弃土场的变更情况进行了介绍,并针对弃土场变更过程中存在的选址合理性、措施科学性等问题进行了分析及归纳,提出了建议,为同类项目弃土场的变更水土保持措施设计提供技术参考。     

The role of plant uptake on the removal of organic matter and nutrients in subsurface flow constructed wetlands: a simulation study.

Plants in constructed wetlands have several functions related to the treatment processes. It is generally agreed that nutrient uptake is a minor factor in constructed wetlands treating wastewater compared to the loadings applied. For low loaded systems plant uptake can contribute a significant amount to nutrient removal. The contribution of plant uptake is simulated for different qualities of water to be treated using the multi-component reactive transport module CW2D. CW2D is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The model for plant uptake implemented describes nutrient uptake coupled to water uptake. Literature values are used to calculate potential water and nutrient uptake rates. For a constructed wetland treating municipal wastewater a potential nutrient uptake of about 1.9% of the influent nitrogen and phosphorus load can be expected. For lower loaded systems the potential uptake is significantly higher, e.g. 46% of the nitrogen load for treatment of greywater. The potential uptake rates could only be simulated for high loaded systems i.e. constructed wetlands treating wastewater. For low loaded systems the nutrient concentrations in the liquid phase were too low to simulate the potential uptake rates using the implemented model for plant uptake.     

浅析建设项目水土保持方案对发展森林碳汇的意义

提升和充分发挥森林碳汇功能,对遏制气候恶化、缓减生态环境退化起着关键的作用。在我国现行的工程项目建设中,实行水土保持方案配套实施制度,其目的主要是为了减少水土流失。本文在分析了水土保持措施对增加森林碳汇的作用的基础上,提出在编制水土保持方案时,应最大可能地兼顾水土保持方案的森林碳汇功能。     

Responses to local and global stressors in the large southern perialpine lakes: Present status and challenges for research and management

Here, we review the state-of-the-art of limnological investigations in the large and deep lakes south of the Alps (DSLs), lakes Garda, Maggiore, Como, Iseo and Lugano. In the pre-industrial age, these lakes were ultra- or oligotrophic. Increasing anthropogenic pressure and the impact of global warming has led to an acceleration of eutrophication and a decrease in the frequency of full mixing episodes, which have induced a state of meromixis in lakes Lugano and Iseo. In the last two decades, other changes have been identified, including fundamental variations in the long-term dynamics and structure of phytoplankton communities, identification of new toxigenic cyanobacteria and cyanotoxins, increases in the introduction and establishment of allochthonous species, and continuous detection of new, emerging chemical pollutants. Overall, these fundamental changes are quickly transforming the features of the DSLs. The ability to document and reconstruct changes in lake aquatic biota and micropollutants was strongly dependent on both research efforts and the availability of technologies to appraise these changes. In this context, the ongoing adoption of new technological tools, such as high-frequency monitoring and high throughput sequencing, is opening the way to a new level of comprehension of physical, chemical and biological processes, and aquatic biodiversity. New outlooks and new conceptual frameworks are necessary to cope with the huge dimensions of high-throughput data and analysis of big data.     

江西省水土保持监督执法工作的现状和对策

江西省水土保持监督执法工作在水土保持法规宣传、配套法规制定、执法队伍建设、人为水土流失普查、执法试点等方面进行了探索，取得了成绩，但各地发展不平衡，今后，需要采取措施，进一步完善监督执法工作。     

水土保持措施防治面源污染效益研究——以河南省淅川县坡地柑橘种植为例

为保护丹江口水库水质,探索河南丹库汇水流域特色作物生态种植与氮磷污染负荷削减技术,在河南省淅川县建立坡地柑橘试验小区,采取室外人工模拟降雨,对微地形改造和植物篱的试验小区开展试验观测。结果表明,与对照小区对比,种植柑橘具有一定的水土保持效果,采取树盘等微地形改造措施能显著减少泥沙流失,而采取植物篱措施则可同时大幅度减少泥沙、全氮及全磷流失。为该类地区调整土地利用结构、扩大柑橘种植面积提供科学依据。     

Stable states,buffers and switches: An ecosystem approach to the restoration and management of shallow lakes in The Netherlands

Lake restoration in the Netherlands has been focused mainly on the control of external P loading from point sources. However, this approach did not result in the water quality desired. The algae-dominated turbid water state may be extremely stable, and then additional measures are necessary to remove certain ‘blockages’ such as: the persistent bloom of Oscillatoria algae, the P release from the lake sediments, and the abundance of fish, preventing zooplankton and submerged macrophytes from developing . This paper addresses: (1) the need for an ecosystem approach, (2) the resistance of shallow lake ecosystems to changes in nutrient loading, (3) the concept of stable states, buffers and switches, and (4) the perspectives for lake restoration in the Netherlands. Priority should be given to fighting the Oscillatoria blooms. Winter flushing with water low in TP and algae proved to be an effective tool for reducing these blooms. Reduction of planktivorous fish, such as bream and roach, could enhance the top-down control of algae through the grazing by zooplankton, particularly by the large Daphnia species.     

The relevance of species-based indicators as a tool for evaluating the structure of exploited fish assemblages: a comparative study of two tropical lakes in Mali, West Africa

A comparative study of the fish communities in two lake ecosystems in Mali (Lakes Manantali and Selingue) was based on monitoring small‐scale fishery landings for a 13‐month period. The main difference between the two lakes is the fishing pressure, being higher in Lake Selingue and lower in Lake Manantali. The effects of fishing on the structure of the fish communities in the two lakes were analysed with the use of diversity indices, rank species abundance (RSA) and abundance–biomass comparative curve (ABC) methods. The diversity differed significantly between the lakes, being higher for Lake Selingue. Analysis of the community structure, using RSA curves, indicated a more regular distribution of the weights between fish species for Lake Selingue than for Lake Manantali. The two lakes exhibited different exploited fish community structures. For Lake Selingue, the fishery was based on smaller‐sized species, compared to that for Lake Manantali. The indicators based on the species composition of exploited fish communities, in terms of abundance and life‐history traits, seemed to be more relevant in this study. Indicators such as diversity indices and RSA curves depend strongly on the exploitation strategy, being unreliable for evaluating exploited fish communities from catch data.     

The evolution of water management in Alberta,Canada: the influence of global management paradigms and path dependency

This study examines the evolution of Alberta's water management framework in response to changing demands, national policy and global paradigms. The South Saskatchewan River basin is presented as the crucible for Albertan water policy, given the severity of droughts, over-allocation, and environmental degradation. The analysis finds a distinct trend in the past two decades towards integration and sustainable management, as affirmed by the globally dominant integrated water resource management paradigm. The concept of path dependency offers valuable insight into the barriers posed by past policy frameworks to water management systems, particularly in relation to the prior-allocation system of water rights.     

Monitoring of environmental flow outcomes in a large river basin: The Commonwealth Environmental Water Holder's long‐term intervention in the Murray–Darling Basin,Australia

The Murray–Darling Basin in south‐eastern Australia contains over 70,000 km² of wetlands and floodplains, many of which are in poor condition. In response, Australian governments have committed to a major restoration program, the Murray–Darling Basin Plan that includes management of 2,750 Gl of environmental water to protect and restore aquatic ecosystems. The restoration is being undertaken within an adaptive management framework that includes monitoring the outcomes of environmental flows in seven river valleys. This paper provides an overview of the 5‐year monitoring project and some preliminary results. Monitoring design considered the Basin Plan's environmental objectives, conceptual models of ecosystem responses to flow, and an outcomes framework linking flow responses to the environmental objectives. Monitoring indicators includes ecosystem type, vegetation, river metabolism, and fish. Responses are evaluated to identify the contribution of environmental flows to Basin Plan environmental objectives and continual improvements in management. The program is unique in that it seeks to monitor long‐term outcomes of environmental flows at the river basin scale. Despite many challenges, the monitoring has become a key part of the adaptive management of environmental flows in the Murray–Darling Basin.     

湖北省城区输变电工程水土保持监测实践与分析——以武汉戴家湖110kV输变电工程为例

为控制因输变电类开发建设项目所导致的生态环境恶化,必须加强项目区水土流失动态监测工作。以武汉戴家湖110 kV输变电工程为例,介绍了工程建设过程中水土保持监测工作的实施情况,并对工程水土流失防治效果进行了评价。最后指出,由于实施了水土保持防治措施,项目区各地表扰动类型侵蚀强度降低,土壤流失量明显减少,各项水土流失防治指标均符合预期防治目标的要求。     

Strategies for building partnerships in the context of river basin management: The role of ecotechnology and ecological engineering

The theory of ecosystem management is described and its importance and application to the management of river basins and watersheds is considered. Eleven ecosystem principles and their application within the context of watershed management are discussed. The development of partnerships in river basin management is important. In their development, the research system, public and private sectors, and community participation are seen as key components.     

The role of coastal processes in the management of the mouth of the River Murray,Australia: Present and future challenges

The Murray–Darling Basin is the largest river system in Australia to enter the sea. Prior to regulation of water flows, the Murray Mouth remained open to the sea even during droughts. An open mouth assists in sustaining the ecology of a Ramsar listed wetland and enables the flushing of salt, nutrients, and suspended sediments to the sea. Construction of barrages designed to prevent saltwater ingress has separated the estuary into two sections, a set of freshwater lakes and a saline tidal lagoon area, creating a unique set of management challenges. Under current overextraction of water resources upstream, river flows have been largely insufficient to counter wave and tide processes, which propel marine sands thereby constricting the Murray Mouth. Dredging has been required to maintain an open entrance. Managing this system is part of a 2012 agreement between state and federal governments, through the Murray–Darling Basin Plan. This plan recognizes a healthy end of system; however, the hydrological models failed to factor in the power of the sea in blocking the Murray Mouth. The plan requires that there will be sufficient river flows for the mouth to be open 95% of the time without dredging. Currently, sand ingress from the sea requires dredging most of the time. It is unlikely that there will be sufficient river flows to counteract continued sequestration of marine sand into the mouth. Sea level rise and decreased rainfall in the southern half of the Basin under climate change conditions will require a review of management options to prevent the long‐term degradation of the end of system.     

Revisiting the history,concepts and typologies of community management for rural drinking water supply in India

Community management has been widely criticized, yet it continues to play a significant role in rural drinking water supply. In India, as with other ‘emerging’ economies, the management model must now adapt to meet the policy demand for ever-increasing technical sophistication. Given this context, the paper reviews the history and concepts of community management to propose three typologies that better account for the changing role of the community and external support entities found in successful cases. It argues that external support entities must be prepared to take greater responsibility for providing ongoing support to communities for ensuring continuous service delivery.     

The role of riparian woods in regulating nitrogen fluxes between the alluvial aquifer and surface water: A conceptual model

Conceptual models are proposed to explain nitrogen fluxes in the soils of riparian zones in relation to the different modalities of water logging and nitrate inputs. Non-submerged, temporarily submerged, and always submerged, sites are considered in both winter and summer. It is shown that capacities for epuration are elevated for nitrate loads from the alluvial aquifer during the lateral transfer of water from agricultural land to the river through the riparian zone. About 30 m of groundwater flow under the riparian wood studied is sufficient to remove all nitrate. Denitrification rates up to 50 mg N₂ per m² per day were observed in the field, but a potential for more denitrification exists. The efficiency of the riparian woods as natural filters regulating nutrient transfers to the river deserves more consideration in river management.     

The impact of cold water releases on the critical period of post‐spawning survival and its implications for Murray cod (Maccullochella peelii peelii): a case study of the Mitta Mitta River,southeastern Australia

The effects of cold water releases, as a by‐product of storing irrigation water in large dams, has been a source of great concern for its impact on native freshwater fish for some time. The Mitta Mitta River, northeast Victoria, is impacted by altered thermal regimes downstream of the fourth largest dam in Australia, Dartmouth dam, with some daily temperatures 10–12°C below normal. Murray cod (Maccullochella peelii peelii) were endemic to the Mitta Mitta River; however, resident Murray cod have not been found in this river since 1992. The response of eggs and hatched larvae from Murray cod to different temperature gradients of water were measured and the post‐spawning survival recorded. As a case study, post‐spawning survival was then inferred from flow data for each year of operation of Dartmouth Dam, recorded since first operation in 1978, and included in a stochastic population model to explore the impact of the altered (historical) thermal regime on population viability. Experimental results revealed no egg and larval survival below 13°C and predicted historical temperature regimes point to more than 15 years of low temperatures in the Mitta Mitta River. Population modelling indicates that the impact of cold water releases on post‐spawning survival is a significant threatening process to the viability of a Murray cod population. Additionally, we consider changes to the thermal regime to explore how the thermal impact of large dams may be minimized on downstream fish populations through incrementally increasing the temperature of the releases. The modelled Murray cod population responds to minor increases in the thermal regime; however, threats are not completely removed until an increase of at least 5–6°C. Copyright © 2005 John Wiley & Sons, Ltd.     

Impacts of climate change on hydrology and water quality: Future proofing management strategies in the Lake Simcoe watershed,Canada

The impacts of climate change on hydrology and water quality of the Black River, a tributary of Lake Simcoe, Canada, were assessed for the period 2001–2100, by integrating two models, HBV and INCA-P, and using statistically downscaled data from the Global Circulation Model CGCM3 for two IPCC scenarios (A1b and A2). The effectiveness of catchment management strategies was assessed across the 21st century by simulating controls on sewage treatment works and fertiliser applications, and implementing buffer strips and bank erosion controls.