State and management of wetlands in Bangladesh

Wetlands are a vital link between land and water in Bangladesh. A majority of the people of Bangladesh are critically dependent on wetlands. In this paper, the values of wetlands, causes and effects of wetlands degradation, as well as the present wetlands management approach, are analyzed and recommendations for wetlands management are suggested based on participatory rural appraisal (PRA), field visit, personal experience, and existing literature and information. Wetlands play a crucial role in maintaining the ecological balance of ecosystems, but wetlands habitat of Bangladesh is under constant threat due to increase of population, intensive agriculture, overfishing, siltation, pollution, ill-planned infrastructures, lack of institutional coordination, lack of awareness, etc. As a result biodiversity is reducing, many species of flora and fauna are threatened, wetlands-based ecosystem is degenerating, and the living conditions of local people are deteriorating as livelihoods, socioeconomic institutions, and cultural values are affected. Wetlands management is not addressed separately in water management activities of Bangladesh. In order to balance human needs and wetlands conservation, a mainly community-based wetlands management approach has been taken in Bangladesh, but this is not enough to prevent the degradation of wetlands. Therefore, Bangladesh now needs a comprehensive strategy combining political, economic, social, and technological approaches to stop further degradation of wetlands. Therefore, wetlands management should be incorporated into a system of integrated land and water use and, indeed, into the socioeconomic system of the country. Policies, strategies, and management plans for sustainable use and conservation of wetlands of Bangladesh must be based on solid knowledge and understanding of their ecological and socioeconomic functions and processes.     

The ecology of The Netherlands wetlands: characteristics,threats, prospects and perspectives for ecological research

Wetlands are among the worlds' most important, but also most threatened, environmental resources. Wetland losses have been in progress particularly from the industrial revolution onwards, because wetland functions could not successfully compete for space with other land uses. Wetlands became recently foci of conservation efforts because of the increased awareness of their importance in water management and wildlife conservation, and because of the diversity of their habitats. The Netherlands are relatively rich in wetlands: 16% of its' territory is regarded as internationally important wetland and 7% has been registered as such. The major Dutch wetland types are: coastal ecosystems, large riverine systems, base-rich freshwater systems, and nutrient-poor freshwater systems. Most threats to the Dutch wetlands are of man-made origin. They comprise: (1) Changes in hydrology leading to changed discharges, currents and desiccation; (2) Acidification; (3) Eutrophication; and (4) Toxification. Long-term threats are largely climate-change related, and concern temperature rise and the UV-B increase in irradiation. General conservation goals also apply to wetlands but Ramsar-registered wetlands have a special status. Conservation of the Dutch wetlands is difficult, because of the high population density of the country and its inherent threats. However, ecological targets and standards are increasingly set in national Policy Plans and international agreements. Rehabilitation and creation of wetlands is presently widely advocated, and sometimes realised. For ecological research, the sustainability of wetlands should get top priority. Such a research programme would focus on understanding the underlying ecological processes in natural and man-dominated wetland systems to prescribe conservation, rehabilitation and management strategies that would enhance the sustainability of these systems. Within this framework special attention should be directed to studies (1) At the ecosystem level of ecosystem parameters, of which natural oscillations and trends in time, and on which the impact of disturbances are quantified. Particularly these studies, in which often simulation models are used as tools for interpretation, can provide the basis for extrapolations in space and time; (2) On adaptation capacity and mechanisms of (groups of) species to extreme environmental conditions; (3) On (mutual) relationships between plants, animals and microorganisms (e.g. competition, grazing and mineralization); (4) On dispersion between small wetlands. For the contemporary quantitative assessment of the long-term effects of climate changes, the effects of temperature rise and increase in UV-B irradiation on individual species, communities and ecosystems should also be studied.     

A synthesis of past,current and future research for protection and management of papyrus (Cyperus papyrus L.) wetlands in Africa

Papyrus wetlands (dominated by the giant sedge Cyperus papyrus L.) occur throughout eastern, central and southern Africa and are important for biodiversity, for water quality and quantity regulation and for the livelihoods of millions of people. To draw attention to the importance of papyrus wetlands, a special session entitled “The ecology of livelihoods in papyrus wetlands” was organized at the 9th INTECOL Wetlands Conference in Orlando, Florida in June 2012. Papers from the session, combined with additional contributions, were collected in a special issue of Wetlands Ecology and Management. The current paper reviews ecological and hydrological characteristics of papyrus wetlands, summarizes their ecosystem services and sustainable use, provides an overview of papyrus research to date, and looks at policy development for papyrus wetlands. Based on this review, the paper provides a synthesis of research and policy priorities for papyrus wetlands and introduces the contributions in the special issue. Main conclusions are that (1) there is a need for better estimates of the area covered by papyrus wetlands. Limited evidence suggests that the loss of papyrus wetlands is rapid in some areas; (2) there is a need for a better understanding and modelling of the regulating services of papyrus wetlands to support trade-off analysis and improve economic valuation; (3) research on papyrus wetlands should include assessment of all ecosystem services (provisioning, regulating, habitat, cultural) so that trade-offs can be determined as the basis for sustainable management strategies (‘wise use’); (4) more research on the governance, institutional and socio-economic aspects of papyrus wetlands is needed to assist African governments in dealing with the challenges of conserving wetlands in the face of growing food security needs and climate change. The papers in the special issue address a number of these issues.     

A Hybrid Wetland Map for China: A Synergistic Approach Using Census and Spatially Explicit Datasets

Wetlands play important ecological, economic, and cultural roles in societies around the world. However, wetland degradation has become a serious ecological issue, raising the global sustainability concern. An accurate wetland map is essential for wetland management. Here we used a fuzzy method to create a hybrid wetland map for China through the combination of five existing wetlands datasets, including four spatially explicit wetland distribution data and one wetland census. Our results show the total wetland area is 384,864 km², 4.08% of China’s national surface area. The hybrid wetland map also shows spatial distribution of wetlands with a spatial resolution of 1 km. The reliability of the map is demonstrated by comparing it with spatially explicit datasets on lakes and reservoirs. The hybrid wetland map is by far the first wetland mapping that is consistent with the statistical data at the national and provincial levels in China. It provides a benchmark map for research on wetland protection and management. The method presented here is applicable for not only wetland mapping but also for other thematic mapping in China and beyond.     

Wetlands of Sub-Saharan Africa: distribution and contribution of agriculture to livelihoods

Wetlands contribute in diverse ways to the livelihoods of millions of people in Sub-Saharan Africa. In many places they are inextricably linked to cropping and livestock management systems. At the same time, increasing population in conjunction with efforts to increase food security is escalating pressure to expand agriculture within wetlands. The environmental impact of wetland agriculture can, however, have profound social and economic repercussions for people dependent on ecosystem services other than those provided directly by agriculture. Currently, the basis for making decisions about the extent to which wetlands can be sustainably used for agriculture is weak. This paper provides an overview of wetland distribution, type and condition across Sub-Saharan Africa. Findings from an investigation of wetland use conducted in Tanzania are presented. These highlight the reliance of communities on both wetland agriculture and natural resources, and show that the nature of household dependence varies significantly from place to place and as socio-economic status changes. Consequently, incentives to manage wetland resources will differ markedly, not only from one location to another, but also across socio-economic groups within the same community. This complexity highlights the need for critical analysis of the social and economic factors that underpin the dynamics of wetland resource use in the development of sustainable management plans.     

The application of a framework for assessing ecological condition and sustainability of use to three wetlands in Malawi

In Africa, the direct use of wetlands has long contributed to livelihoods, but use may lead to the degradation of wetlands. In order to better understand how the biophysical features of a wetland influence the sustainability of its use, an investigation was undertaken of the ecological condition and use of three wetlands in the Kasungu District, Malawi, where human pressures on wetlands are high. The first wetland, at the head of the catchment, had sandy soils and a gentle longitudinal slope, the second wetland, lower in the catchment, had clay soils and a steeper longitudinal slope, and the third wetland was intermediate. A framework was applied to score five functional components of ecological condition: hydrology, geomorphology, soil organic matter (SOM) accumulation, nutrient cycling and vegetation composition in terms of human impact, based on pre-defined field indicators. The framework highlighted particular vulnerabilities of individual wetlands in the face of human pressure. Vulnerability varied greatly across the wetlands in terms of: recovery of native vegetation composition following cultivation, geomorphic change through gully erosion and depletion of SOM. The framework is recommended for wider application in Africa as a means of highlighting the specific vulnerabilities of individual wetlands and for the improved focus of organizations which promote the ecologically sustainable use of wetlands.     

Restoration Enhances Wetland Biodiversity and Ecosystem Service Supply,but Results Are Context-Dependent: A Meta-Analysis

Wetlands are valuable ecosystems because they harbor a huge biodiversity and provide key services to societies. When natural or human factors degrade wetlands, ecological restoration is often carried out to recover biodiversity and ecosystem services (ES). Although such restorations are routinely performed, we lack systematic, evidence-based assessments of their effectiveness on the recovery of biodiversity and ES. Here we performed a meta-analysis of 70 experimental studies in order to assess the effectiveness of ecological restoration and identify what factors affect it. We compared selected ecosystem performance variables between degraded and restored wetlands and between restored and natural wetlands using response ratios and random-effects categorical modeling. We assessed how context factors such as ecosystem type, main agent of degradation, restoration action, experimental design, and restoration age influenced post-restoration biodiversity and ES. Biodiversity showed excellent recovery, though the precise recovery depended strongly on the type of organisms involved. Restored wetlands showed 36% higher levels of provisioning, regulating and supporting ES than did degraded wetlands. In fact, wetlands showed levels of provisioning and cultural ES similar to those of natural wetlands; however, their levels of supporting and regulating ES were, respectively, 16% and 22% lower than in natural wetlands. Recovery of biodiversity and of ES were positively correlated, indicating a win-win restoration outcome. The extent to which restoration increased biodiversity and ES in degraded wetlands depended primarily on the main agent of degradation, restoration actions, experimental design, and ecosystem type. In contrast, the choice of specific restoration actions alone explained most differences between restored and natural wetlands. These results highlight the importance of comprehensive, multi-factorial assessment to determine the ecological status of degraded, restored and natural wetlands and thereby evaluate the effectiveness of ecological restorations. Future research on wetland restoration should also seek to identify which restoration actions work best for specific habitats.     

Resource dependence and attitudes of local people toward conservation of Kabartal wetland: a case study from the Indo-Gangetic plains

Wetlands are rapidly disappearing from the earth's surface because of agricultural conversion and other land-use changes. The Indo-Gangetic biogeographic zone is a water-surplus area and it abounds in numerous wetlands and floodplains. Kabartal is one such freshwater wetland ecosystem situated in the mid Ganges basin. The wetland not only supports a large population of migratory and residential waterfowl but also plays an equally important role in the local economy and livelihoods of people. The objective of this paper is to examine the different wetland–society linkages, resource dependence, and attitudes of the people living in the peripheral villages of Kabartal. The results indicate that 67% of people depend on the wetland for different types of subsistence and commercial goods including fodder, fuel wood, construction materials, and fish. Kabartal wetland, like many other wetlands of the region, is used simultaneously for rice cultivation, fishing, and many other uses. This has resulted in conflict between different stakeholder groups. The non-settlement of land rights in the Kabartal sanctuary area has further complicated the situation. Agriculture was rated as the most important use of the wetland and was the basic source of income in the area. This was apparent from the attitudes of people, and most of the respondents demanded draining of the water to make more land available for agriculture. The study reveals the high dependence of people in low-income groups on wetland resources. In such a scenario, although the concept of conservation is well supported, the economic conditions of people dictate otherwise. A general lack of awareness about the ecological functions of wetlands points to the need for conservation education. Managing the wetland on the basis of zone concepts and involving local people in alternative income-generating activity by use of extension programs has been suggested as a means of reducing pressure on agricultural land and also reducing the threat to Kabartal wetland.     

Environmental watering triggers rapid frog breeding in temporary wetlands within a regulated river system

The Murray–Darling basin is the most extensively regulated river system in Australia and delivery of environmental water is increasingly being used in its management. Due to their sensitivity to hydrological changes, frogs are often targets of environmental watering actions, and site-specific data on their habitat and water requirements are essential for achieving optimal ecological outcomes. I investigated the spatial and temporal response of frogs to the environmental watering of temporary wetlands in the lower River Murray region to determine if watering (timing, duration and quality) triggered a breeding response and provided opportunities for juvenile recruitment. Frog and tadpole surveys were conducted each month from December 2014 to April 2015 at watered temporary wetlands and permanent wetlands along on the River Murray in South Australia. All seven frog species known from the lower Murray valley bred opportunistically after deliberate flooding of temporary wetland sites. Breeding was immediate and was observed at all watered sites. Tadpole development was largely synchronous and rapid, with the majority of frogs metamorphosing 3 to 4 months after wetlands were inundated. The abundance and diversity of tadpoles and frogs was significantly greater in watered wetlands than in permanent wetlands. Wetlands required inundation for a minimum duration of 4 months over summer and autumn to allow sufficient time for tadpoles to complete development. Environmental watering of wetlands via pumping, whilst highly localised, can target key ecological assets in dry conditions, and may provide critical breeding opportunities and refugia for maintaining frog species and their ecological roles.     

Impacts of human‐induced environmental change in wetlands on aquatic animals

Many wetlands harbour highly diverse biological communities and provide extensive ecosystem services; however, these important ecological features are being altered, degraded and destroyed around the world. Despite a wealth of research on how animals respond to anthropogenic changes to natural wetlands and how they use created wetlands, we lack a broad synthesis of these data. While some altered wetlands may provide vital habitat, others could pose a considerable risk to wildlife. This risk will be heightened if such wetlands are ecological traps – preferred habitats that confer lower fitness than another available habitat. Wetlands functioning as ecological traps could decrease both local and regional population persistence, and ultimately lead to extinctions. Most studies have examined how animals respond to changes in environmental conditions by measuring responses at the community and population levels, but studying ecological traps requires information on fitness and habitat preferences. Our current lack of knowledge of individual‐level responses may therefore limit our capacity to manage wetland ecosystems effectively since ecological traps require different management practices to mitigate potential consequences. We conducted a global meta‐analysis to characterise how animals respond to four key drivers of wetland alteration: agriculture, mining, restoration and urbanisation. Our overarching goal was to evaluate the ecological impacts of human alterations to wetland ecosystems, as well as identify current knowledge gaps that limit both the current understanding of these responses and effective wetland management. We extracted 1799 taxon‐specific response ratios from 271 studies across 29 countries. Community‐ (e.g. richness) and population‐level (e.g. density) measures within altered wetlands were largely comparable to those within reference wetlands. By contrast, individual fitness measures (e.g. survival) were often lower, highlighting the potential limitations of using only community‐ and population‐level measures to assess habitat quality. Only four studies provided habitat‐preference data, preventing investigation of the potential for altered wetlands to function as ecological traps. This is concerning because attempts to identify ecological traps may detect previously unidentified conservation risks. Although there was considerable variability amongst taxa, amphibians were typically the most sensitive taxon, and thus, may be a valuable bio‐indicator of wetland quality. Despite suffering reduced survival and reproduction, measures such as time to and mass at metamorphosis were similar between altered and reference wetlands, suggesting that quantifying metamorphosis‐related measures in isolation may not provide accurate information on habitat quality. Our review provides the most detailed evaluation to date of the ecological impacts of human alterations to wetland ecosystems. We emphasise that the role of wetlands in human‐altered ecosystems can be complex, as they may represent important habitat but also pose potential risks to animals. Reduced availability of natural wetlands is increasing the importance of altered wetlands for aquatic animals. Consequently, we need to define what represents habitat quality from the perspective of animals, and gain a greater understanding of the underlying mechanisms of habitat selection and how these factors could be manipulated. Furthermore, strategies to enhance the quality of these wetlands should be implemented to maximise their conservation potential.     

Sustainable planning for a coastal wetland system with an integrated ANP and DPSIR model for conflict resolution

Wetlands are important ecosystems on earth due to their capability of preserving water sources, mediating flooding, providing habitats for wildlife, and stabilizing coastlines. Wetlands play a critical role in regional sustainable development because of their ability to enhance resilience against extreme weather events. Maintaining coastal sustainability requires consideration of both the health of coastal wetlands and the resilience of urban systems while mitigating the conflict among social, economic, and environmental goals in land usages around coastal wetland environment. This study investigates a sensitive coastal wetland system located at central Taiwan for demonstration of a sustainable planning practice with an integrated model based on network topology in a socio-ecological context. There are two parts of the integrated model. Whereas a Driving force–Pressure–State–Impact–Response (DPSIR) model helps delineate the complex behaviors among different stakeholders by identifying various indicators, the analytic network process (ANP) quantifies the network topology of DPSIR. According to the survey via questionnaires answered by a group of experts, the DPSIR model is composed of 32 major indicators that can be networked by ANP. The results reveal that an effective ecological conservation depends on a series of mitigation actions, including river and habitat restorations, pollution control, green tourism, and integrated community development via better zoning policies.     

THE WHITE-BREASTED CORMORANT IN SOUTH AFRICA

Akinsola, O.A., Ezealor, A.U. &; Polet, G. 2000. Conservation of waterbirds in the Hadejia-Nguru Wetlands, Nigeria: current efforts and problems. Ostrich 71 (1 &; 2): 118–121.

The ornithological importance of the Hadejia-Nguru wetlands at both national and international levels is well known. Current efforts at conserving the avifauna of the wetlands started with the establishment of the Hadejia-Nguru Wetlands Conservation Project (HNWCP) in 1987, as a joint international initiative to promote sustainable use of this hydric ecosystem in the otherwise semi-arid zone of north-eastern Nigeria. The present phase of the project started in 1995 with the major goal of maintaining the natural resources and function of the wetlands. This paper discusses recent activities of the project that have been directed towards conserving the wetlands, particularly its avifauna.

Bird monitoring and the annual dry season (northern winter) waterbird surveys remain the most publicised bird conservation effort of the HNWCP. However, recognition of the vital and central role of water in maintaining the ecological health of the wetlands has prompted the project to evolve a new strategy of regular meetings of the wetlands' water stakeholders (tagged “water-use advocacy”), to resolve periodic water-shortage and distribution problems.

Uncontrolled hunting of birds and habitat loss remain pressing problems throughout the wetland. The HNWCP has made efforts to curb these problems by sensitising the local communities through awareness campaigns and harnessing the efforts of concerned local and national organisations. However, the HNWCP has had difficult experiences regarding the problems of crop damage by avian pests from the wetlands.     

湿地氮素传输过程研究进展

综述了湿地氮素传输过程的研究进展。湿地氮素传输过程包括物理过程、化学过程和生物过程 ,与土壤、植物的发生、发育紧密联系在一起 ,并形成了空气 -水 -土 -生命系统中物质循环和能量流动的复杂网络。湿地硝态氮的淋失直接威胁着湿地地下水水质安全 ,N2 O源汇转变受土壤和水体等环境因子的制约 ,氨挥发则与水体 p H值密切相关排放。湿地氮素的化学转化过程是矿质养分供给和 N2 O产生的主要机制 ,受环境因子和人类活动干扰的影响 ;动力学模型可用于描述氮素的化学转化过程。湿地植物的吸收和累积以及微生物的分解过程是湿地氮素循环的重要环节。最后分析了当前国内外研究中存在的不足 ,并对未来研究的重点领域进行了展望     

Rapid ecosystem service assessment of the impact of Koshi Tappu Wildlife Reserve on wetland benefits to local communities

Wetlands are important for biodiversity and are critical for human livelihoods, providing ecosystem services such as clean water, food and global climate regulation. Many wetlands are threatened by land-use conversion, but creating protected areas to conserve them can benefit both biodiversity and people. However, protected areas can also have socio-economic costs for local communities. At Koshi Tappu Wildlife Reserve in Nepal, there has been historical conflict over the creation of the reserve. In light of a recent proposal to expand the protected area, we explored the use of a rapid ecosystem service assessment tool (TESSA) to assess the impact of the reserve on some of the key ecosystem services the site provides. Based on the ecosystem services assessed we estimated that the economic value of KTWR as a protected area is $350,000 y^?1 ($20 ha^?1y^?1) less than the value of the wetland in an unprotected state. However, this difference is relatively small and is affected by the limitations of the approach and sensitivity of the values to market prices and the assumptions made, so we cannot draw clear conclusions on the overall impact of the reserve in relation to local livelihoods. However, we found TESSA to be a useful tool for engaging with the stakeholder community and for highlighting the potential impacts that land use decisions can have on key ecosystem services. In the context of informing the potential expansion of the reserve, it is clear that further intensive socio-economic assessment of the potential costs and benefits is necessary.     

Ensuring the adaptive potential of Coastal wetlands of India- the need of the hour for sustainable management

India is endowed with a variety of coastal wetlands viz., mangroves, seagrasses, saltmarshes, coral reefs, lagoons and tidal flats, and the country is also a signatory to the Ramsar Convention on Wetlands and the Convention of Biological Diversity, besides having a robust framework of laws and policies, governing the wetland conservation. However, the conservation strategies can better be improved in the context of increasing pressures and threats and limited success of restoration/rehabilitation. Land conversion and ecological degradation of coastal wetlands are the stressors, associated with rapid coastal developmental activities and climate change. The coastal wetlands require desired habitat niche and hence, the conversion of coastal wetlands to other land uses (including agricultural and urban lands) may lead to permanent loss, whereas ecologically degraded coastal wetlands may be resilient if supported by effective protection measures. Preventing the habitat conversion and maximizing the adaptive potential (viz., the ability of populations or species to adapt to rapid environmental change with minimal disruption) by preserving the ecological health are the need of the hour to safeguard the existing coastal wetlands and sustain the provisional ecosystem services offered by them rather than short-term increase in area by unproductive restoration/rehabilitation efforts. Since coastal wetlands are flow through ecosystems, preserving the hydrological connectivity, facilitating the connectivity between adjacent ecosystems and protection of natural corridors are potential strategies that are required to enhance the adaptive potential of coastal wetlands. This analysis calls for site-specific, long-term and integrated ecosystem-based protection, management and rehabilitation strategies based on scientific principles and enforcing the effective legislative measures to regularize the coastal developmental activities in India.

     

基于3S技术的图们江流域湿地生态安全评价与预警研究

图们江是我国重要的国际性河流之一,随着我国经济的迅速崛起,图们江地区进入到多国合作联合开发阶段,该区环境也因此受到了不同程度的干扰和破坏,对该区域进行湿地生态安全评价与预警研究,可为图们江流域生态环境的可持续发展提供依据。以图们江流域湿地生态安全为出发点,基于PSR模型构建了适合该区域生态环境的生态安全评价指标体系,在3S技术支持下,通过解译1976年、1990年、2000年、2010年4个年份的TM/MSS影像,获取了这4个时期的景观格局指标数据,并运用层次分析法确定指标权重;在使用逻辑斯蒂增长曲线模型对各个指标进行单指标评价的基础上,使用综合评价法对各个时期的图们江流域湿地生态安全进行评价,最终得到1976年、1990年生态安全值分别为0.650、0.620,湿地生态系统比较安全,2000年、2010年生态安全值分别为0.536、0.454,湿地生态系统处于预警状态,应及时对该区域湿地生态系统进行保护。基于灰色预测模型构建湿地生态安全预测模型,经检验,模型精度较高,可以进行图们江流域湿地生态安全的预测研究。做出了图们江流域未来40a的湿地生态安全预测,分别为0.3903、0.3345、0.2866、0.2456,湿地生态系统处于中度预警状态,并有向重度预警发展的趋势,生态安全面临的威胁越来越严重,急需对本区域湿地生态系统进行保护与管理。     

图们江下游湿地生态系统健康评价

湿地是世界上具有独特结构与功能的生态系统,图们江流域湿地生态系统的健康对该区乃至东北亚地区综合生态系统网络的建设具有重要意义。选择图们江流域下游为研究区,基于压力-状态-响应(PSR)模型,在压力系统、状态系统、响应系统三个层面选取30个指标构建了图们江下游湿地生态系统健康评价指标体系,运用层次分析法和多级模糊综合评判法对研究区湿地生态健康状况进行综合评价,其结果为0.5878,处于亚健康状态。其中,压力系统的健康指数为0.5292,响应系统的健康指数为0.6866,状态系统的健康指数为0.5116,各等级隶属度S=(16.83%, 25.37%, 16.76%, 16.97%,24.07%)。主要表现在研究区域湿地的补水水质差,导致湿地水质污染加重,富营养化现象严重;并且由于人为因素,湿地大面积退化,景观破碎化加剧,功能逐渐丧失,生产力水平下降;急需对本区域湿地进行保护与管理。     

‘HALOPHYTE FILTERS’: THE POTENTIAL OF CONSTRUCTED WETLANDS FOR APPLICATION IN SALINE AQUACULTURE

World consumption of seafood continues to rise, but the seas and oceans are already overexploited. Land-based (saline) aquaculture may offer a sustainable way to meet the growing demand for fish and shellfish. A major problem of aquaculture is nutrient waste, as most of the nutrients added through feed are released into the environment in dissolved form. Wetlands are nature's water purifiers. Constructed wetlands are commonly used to treat contaminated freshwater effluent. Experience with saline systems is more limited. This paper explores the potential of constructed saline wetlands for treating the nutrient-rich discharge from land-based saline aquaculture systems. The primary function of constructed wetlands is water purification, but other ancillary benefits can also be incorporated into treatment wetland designs. Marsh vegetation enhances landscape beauty and plant diversity, and wetlands may offer habitat for fauna and recreational areas. Various approaches can be taken in utilizing plants (halophytes, macro-algae, micro-algae) in the treatment of saline aquaculture effluent. Their strengths and weaknesses are reviewed here, and a conceptual framework is presented that takes into account economic and ecological benefits as well as spatial constraints. Use of the framework is demonstrated for assessing various saline aquaculture systems in the southwestern delta region of the Netherlands.     

Barriers and opportunities for cooperative wetland management: a case study in the greater Rocky Mountain National Park ecosystem

Wetlands Ecology and Management - The boundaries of most protected areas are not large enough to encompass natural processes such as hydrologic and ecological connections between wetlands and...