Agricultural drainage and wetland management in Ontario

Land drainage is recognized as an integral part of agricultural activity throughout the world. However, the increase in agricultural production has resulted in the loss of wetland functions and values. Therefore, wetland management and agricultural drainage illustrate the conflict between economic development and natural values. This research assesses the approval process for agricultural land drainage in Ontario, Canada, to determine how the benefits of increased agricultural production are balanced against the loss of wetland values. A permit review of drainage applications was conducted from 1978 to 1997 in Zorra Township, Ontario, Canada. Data collection also included the document reviews, interviews with government agencies and wetland evaluation files. The selected criteria include efficiency, equity, consistency and adequacy. The results indicate that while the process is efficient, fundamental problems remain with the bargaining process.     

Mapping wetlands in the Lower Mekong Basin for wetland resource and conservation management using Landsat ETM images and field survey data

The Mekong River Basin is considered to be the second most species rich river basin in the world. The 795,000 km(2) catchment encompasses several ecoregions, incorporating biodiverse and productive wetland systems. Eighty percent of the rapidly expanding population of the Lower Mekong Basin (LMB), made up in part by Lao PDR, Thailand, Cambodia and Viet Nam, live in rural areas and are heavily reliant on wetland resources. As the populations of Cambodia and Lao PDR will double in the next 20 years, pressure on natural resources and particularly wetlands can only increase. For development planning, resource and conservation management to incorporate wetland issues, information on the distribution and character of Mekong wetlands is essential. The existing but outdated wetland maps were compiled from secondary landuse-landcover data, have limited coverage, poor thematic accuracy and no meta-data. Therefore the Mekong River Commission (MRC) undertook to produce new wetland coverage for the LMB. As resources, funding and regional capacity are limited, it was determined that the method applied should use existing facilities, be easily adaptable, and replicable locally. For the product to be useful it must be accepted by local governments and decision makers. The results must be of acceptable accuracy (>75%) and the methodology should be relatively understandable to non-experts. In the first stage of this exercise, field survey was conducted at five pilot sites covering a range of typical wetland habitats (MRC wetland classification) to supply data for a supervised classification of Landsat ETM images from the existing MRC archive. Images were analysed using ERDAS IMAGINE and applying Maximum Likelihood Classification. Field data were reserved to apply formal accuracy assessment to the final wetland habitat maps, with resulting accuracy ranging from 77 to 94%. The maps produced are now in use at a Provincial and National level in three countries for resource and conservation planning and management applications, including designation of a Ramsar wetland site of international importance.     

Identifying Determinants of Nations' Wetland Management Programs Using Structural Equation Modeling: An Exploratory Analysis

Integrated management and policy models suggest that solutions to environmental issues may be linked to the socioeconomic and political characteristics of a nation. In this study, we empirically explore these suggestions by applying them to the wetland management activities of nations. Structural equation modeling was used to evaluate a model of national wetland management effort and one of national wetland protection. Using five predictor variables of social capital, economic capital, environmental and political characteristics, and land-use pressure, the multivariate models were able to explain 60% of the variation in nations' wetland protection efforts based on data from 90 nations, as defined by level of participation in the international wetland convention. Social capital had the largest direct effect on wetland protection efforts, suggesting that increased social development may eventually lead to better wetland protection. In contrast, increasing economic development had a negative linear relationship with wetland protection efforts, suggesting the need for explicit wetland protection programs as nations continue to focus on economic development. Government, environmental characteristics, and land-use pressure also had a positive direct effect on wetland protection, and mediated the effect of social capital on wetland protection. Explicit wetland protection policies, combined with a focus on social development, would lead to better wetland protection at the national level.     

基于生态学研究制定湿地保护策略：以台湾七股湿地为例

制定合理有效的滨海湿地保护法律制度和管理策略,需要我们理解生物多样性、生态功能和生态系统服务之间的相互关系,并正确地评估滨海湿地的脆弱性以及人类活动和环境变化对湿地的影响。然而,当前滨海湿地保护政策制定过程中有关生态及经济评估数据尚显不足。在此,本文以台湾七股滨海区域作为案例,展示了滨海湿地环境保护政策制定过程生态学研究发挥的影响力,并体现出对其他领域和当地居民相互协作的力量整合,最终实现湿地保护的策略。     

湿地资源的功能类型及其开发与保护

简介了湿地的定义及其分类,并全面概括了湿地的功能类型和保护的意义,指出了中国湿地的现状及开发利用中的生态环境问题,并提出相应的保护对策。     

Floodplain management in London,Ontario, Canada: Assessing implementation of section 28 of the conservation authorities act

An assessment of floodplain regulation by the Upper Thames River Conservation Authority in the City of London for the period 1978–1989 was undertaken. Utilizing a mix of data sources available through the conservation authority office, questionnaires administered to flooplain residents, interviews with relevant government officials, and housing statistics, the study concludes that regulations have been administered in an equitable and efficient manner. However, regulations have had some problems in controlling all development activity and in addressing policy objectives. Problems arise from weaknesses in the Conservation Authorities Act, an ensuing lack of judicial and participating municipal support in prosecuting violations, and inadequate monitoring and enforcement of development activity. Without addressing these issues, the basic problems associated with floodplain management in Ontario will remain.     

Wise Use of Wetlands: Current State of Protection and Utilization of Chinese Wetlands and Recommendations for Improvement

Wetland protection and utilization sometimes appear to be in conflict, but promoting the wise use of wetlands can solve this problem. All countries face the challenge of sustainable development of wetlands to a greater or lesser extent, but the problem is especially urgent in developing countries, such as China, that want to accelerate their economic development without excessive environmental cost. Chinese wetlands contribute greatly to economic development, but improper use of these natural resources has endangered their existence. It is thus necessary to provide scientific guidance to managers and users of wetlands. In this paper, we analyze the present status of Chinese wetland protection and utilization, and discuss problems in six categories: a lack of public awareness of the need for wetland protection; insufficient funding for wetland protection and management; an imperfect legal system to protect wetlands; insufficient wetland research; lack of coordination among agencies and unclear responsibilities; and undeveloped technologies related to wetland use and protection. The wise use of Chinese wetlands will require improvements in four main areas: increased wetland utilization research, scientific management of wetland utilization, improved laws and regulations to protect wetlands, and wider dissemination of wetland knowledge. Based on these categories, we propose a framework for the optimization of wetland use by industry to provide guidance for China and other countries that cannot sacrifice economic benefits to protect their wetlands.     

Modeling wetland loss in coastal Louisiana: Geology,geography, and human modifications

Habitat change in coastal Louisiana from 1955/6 to 1978 was analyzed to determine the influence of geological and man-made changes on landscape patterns within 7.5 min quadrangle maps. Three quantitative analyses were used: principal components anlaysis, multiple regression analysis, and cluster analysis.Regional differences in land loss rates reflect variations in geology and the deltaic growth/decay cycles, man-induced chages in hydrology (principally canal dredging and spoil banking), and land-use changes (principally urbanization and agricultural expansion). The coastal zone is not homogeneous with respect to these variables and the interaction between causal factors leading to wetland loss is therefore locally variable and complex.The relationship between wetland loss, hydrologic changes, and geology can be described with statistically meaningful results, even though these data are insufficient to precisely quantify the relationship. However, these data support the hypothesis that the indirect impacts of man-induced changes (hydrologic and land use) may be as influential as the direct impacts resulting in converting wetlands to open water (canals) or modified (impounded) habitat.Three regions within the Louisiana coastal zone can be defined, based on the potential causal factors used in the analyses. The moderate (mean = 22%) wetland loss rates in region 1 are a result of relatively high canal density and developed area in marshes which overlie sediments of moderate age and depth; local geology acts, in this case, to lessen indirect impacts. On the other hand, wetland loss rates in region 2 are high (mean = 36%), despite fewer man-induced impacts; the potential for increased wetland loss due to both direct and indirect effects of man's activity in these areas is high. Conversely, wetland loss (mean = 20%) in region 3 is apparently least influenced by man's activity in the coastal zone because of sedimentary geology (old, thin sediments), even though these areas have already experienced significant direct habitat alteration and wetland loss.     

湿地水权实践中的成员权表达——基于D村W大塘的案例分析

湿地是我国生态环境系统中的重要组成部分。但长期以来,我国湿地被各方掠夺性开发,湿地生态环境面临的形势严峻。造成这一局面的主要原因是湿地产权界定不清带来的外部不经济。试图通过对发生在一个湿地资源型村庄的案例的分析,来呈现因产权界定不清以致湿地生态环境被破坏的过程:集体化结束后,村社成员试图重新界定湿地水面产权。集体成员权作为一种身份和资格,成为界定湿地水权时最为关键的权利。村社的成员权实践受到受到国家法律政策逻辑和乡土逻辑的双重影响。当双重逻辑在成员权实践中共同发挥作用时,村社成员的权益表达就比较和谐;而当双重逻辑逐渐失能时,村社成员的权益表达就会逐渐不和谐;若这双重逻辑完全消解,村社成员就可能放弃自己的权益表达。后果就是湿地被无序开发,当地的生态环境遭到严重破坏。要改变这一情况,亟需国家政治力量和地方社区力量的集体参与——国家要完善湿地环境保护方面的法律政策,使社会在调处湿地水权纠纷时有法可依;同时基层政府应因地制宜地制定湿地环境保护政策,并应以更加积极的姿态介入到村社湿地水权纠纷调处中;村社成员也应主动对接国家政治力量,“迎法下乡”,使依法治村在村社湿地水权纠纷调处中成为可能。     

Freshwater Wetland dynamics in South Kingstown,Rhode Island, 1939–1972

The extent and causes of changes in the fresh-water wetlands of South Kingstown, Rhode Island were determined through field work and through the analysis of panchromatic aerial photographs taken in 1939 and 1972. During this period, there was a net loss of 0.9 percent of the total area (2345.2 ha) of wetland present in 1939. Highway construction and residential development accounted for most of this loss. Approximately 17 percent of the wetland present in 1939 had changed sufficiently by 1972 to warrant reclassification. Plant succession alone accounted for 57 percent of the changes in wetland types, while man's activities were influential in 41 percent of the cases. Ninety-two percent of the natural changes in wetland types was progressive, while 58 percent of the changes induced by man and undetermined causes was retrogressive. Man's major role was to alter the water regimes and vegetation of wetlands. There was a decrease in wetland diversity as the most abundant type, wooded swamp, grew in area while the abundance of shallow marshes, meadows, and shrub swamps declined. A knowledge of wetland dynamics is essential in the management of wetlands for a diversity of wildlife and other natural values.     

Evaluation of US EPA Environmental Monitoring and Assessment Program's (EMAP)-Wetlands sampling design and classification

The United States Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) will monitor the nation's resources by evaluating the status and trends of selected indicators of condition using a probability-based sampling design. The EMAP-Wetlands program will monitor the condition of the nation's wetlands. The EMAP classification system is an aggregation of the many subclasses of the US Fish and Wildlife Service's National Wetlands Inventory (NWI) classification system. This aggregation results in fewer wetland classes with more wetlands per class than the NWI system. Aggregation of the NWI classification was based primarily on dominant vegetation cover, flooding regimes, dominant water source, and adjacency to rivers and lakes. We evaluated the EMAP classification system and sampling design using NWI digital wetlands data for portions of Illinois, Washington, North Dakota, and South Dakata. Relative numbers of wetlands, total areas, average areas, and common versus rare classes were compared between the EMAP and NWI classification systems. As expected, the EMAP classification provided fewer wetland polygons, each with larger areas, without altering total wetland area. Summary statistics comparing sample estimates to true population parameters (represented by the NWI data) demonstrated the effectiveness of the EMAP sampling design with the exception of rare EMAP classes in the selected regions. Although simple random sampling is inadequate for both large and small wetlands, the EMAP sampling design is readily adapted to provide better estimates for these categories. Aggregating the NWI classification to the EMAP classification provides fewer wetland classes, with more wetlands per class, for EMAP's annual reports and statistical summaries. The research in this report has been funded by the United States Environmental Protection Agency (EPA) under contracts 68-C8-0006 to ManTech Environmental Technology, Inc. and 68-03-3532 to The Bionetics Corporation. Mention of trade names does not constitute endorsement or recommendation for use.     

Wetland boundary and land-use planning in southern Ontario,Canada

There is a general lack of understanding of wetland processes and a general paucity of scientific research to predict the effects of development on wetland boundary. This paper presents the results of a survey of wetland managers as to how they delineate wetland boundaries, define compatible land uses, and restrict land uses adjacent to wetland boundaries. A major finding from the survey is that 75% of land-use planners and wetland managers failed to identify any compatible land use or restricted land use for development proposals that may affect provincially significant wetlands. The government agencies overwhelmingly lack adequate methodologies and/or criteria to delineate and protect wetland boundaries. The paper closes with a plea to consider dynamic hydrological factors in land-use planning.     

Rapid Mapping and Prioritisation of Wetland Sites in the Manawatu–Wanganui Region,New Zealand

The extent of wetland in New Zealand has decreased by approximately 90% since European settlement began in 1840. Remaining wetlands continue to be threatened by drainage, weeds, and pest invasion. This article presents a rapid method for broad-scale mapping and prioritising palustrine and estuarine wetlands for conservation. Classes of wetland (lacustrine, estuarine, riverine, marine, and palustrine) were mapped using Landsat ETM+ imagery and centre-points of palustrine and estuarine sites as ancillary data. The results shown are for the Manawatu–Wanganui region, which was found to have 3060 ha of palustrine and 250 ha of estuarine wetlands. To set conservation priorities, landscape indicators were computed from a land-cover map and a digital terrain model. Four global indicators were used (representativeness, area, surrounding naturalness, and connectivity), and each was assigned a value to score wetland sites in the region. The final score is an additive function that weights the relative importance of each indicator (i.e., multicriteria decision analysis). The whole process of mapping and ranking wetlands in the Manawatu–Wanganui region took only 6 weeks. The rapid methodology means that consistent wetland inventories and ranking can now actually be produced at reasonable cost, and conservation resources may therefore be better targeted. With complete inventories and priority lists of wetlands, managers will be able to plan for conservation without having to wait for the collection of detailed biologic information, which may now also be prioritised.     

Management and valuation of an environmentally sensitive area: Norfolk Broadland,England, case study

Wetlands, like any other environmentally sensitive resource, require very careful evaluation. While it is accepted that all wetlands may be equally valuable in terms of maintaining global life-support systems, individual areas may be ranked according to their uniqueness or the irreplaceability of the resource should the wetland be developed. The various techniques available for evaluating the wetland resource in the development versus conservation conflict situation are critically assessed. Indirect appraisal via the opportunity cost method can generate valuable data which have contributed to the mitigation of such conflict situations.The Broadland, in Norfolk, England, recently designated an environmentally sensitive area (ESA), provides a case study example of wetland management. The search for an acceptable flood alleviation strategy for the ESA is examined in detail. The economic and environmental asset structure of the study area is examined at two levels. A basic screening system is applied to each of the identified flood protection planning units to enable the rank ordering of the units. A more detailed appraisal is then made of the value of selected units so that the cost-effectiveness of any planned expenditure on flood protection works can be assessed. Specific management issues and their likely effect on the environment, in terms of land use for example, are also addressed. The 1986 Agriculture Act marks a potential watershed in British conservation policy. The ESA policy encompasses a dual management strategy that attempts to stimulate compatible agricultural and conservation practices and activities. Other countries that still retain significant unspoiled wetland resources may find that preemptive regulatory government intervention in favor of conservation would help to avoid the worst aspects of the British experience.     

Wetland cultivation and hydrological management in eastern Africa: Matching community and hydrological needs through sustainable wetland use

Wetlands are critical natural resources in developing countries where they perform a range of environmental functions and provide numerous socio-economic benefits to local communities and a wider population. In recent years, however, many wetlands throughout eastern Africa have come under extreme pressure as government policies, socio-economic change and population pressure have stimulated a need for more agriculturally productive land. Although wetland drainage and cultivation can make a key contribution to food and livelihood security in the short term, in the long term there are concerns over the sustainability of this utilization and the maintenance of wetland benefits. This article draws upon recent research carried out in western Ethiopia, which addressed the sustainability of wetland agriculture in an area of increasing food insecurity and population pressure. It discusses the impacts of drainage and cultivation on wetland hydrology and draws attention to local wetland management strategies, particularly those characterized by multiple use of wetlands, where agriculture exists alongside other wetland uses. The article suggests that where multiple wetland uses exist, a range of benefits can be sustained with little evidence of environmental degradation. Ways of promoting and empowering such sustainable wetland management systems are discussed in the context of the wider need for water security throughout the region.     

A rationale for coastal wetland restoration through spoil bank management in Louisiana,USA

The rationale and outline of an implementation plan for restoring coastal wetlands in Louisiana is presented. The rationale for the plan is based on reversing the consequences of documented cause-and-effect relationships between wetland loss and hydrologic change. The main feature is to modify the extensive interlocking network of dredged spoil deposits, or spoil banks, by reestablishing a more natural water flow at moderate flow velocity (<5 cm/sec). Guidelines for site selection from thousands of potential sites are proposed. Examples of suitable sites are given for intermediate marshes. These sites exhibit rapid deterioration following partial or complete hydrologic impoundment, implying a strong hydrologic, rather than sedimentological, cause of wetland deterioration. We used an exploratory hydrologic model to guide determination of the amount of spoil bank to be removed. The results from an economic model indicated a very effective cost-benefit ratio. Both models and practical experience with other types of restoration plans, in Louisiana and elsewhere, exhibit an economy of scale, wherein larger projects are more cost effective than smaller projects. However, in contrast to these other projects, spoil bank management may be 100 to 1000 times more cost effective and useful in wetland tracts <1000 ha in size. Modest spoil bank management at numerous small wetland sites appears to offer substantial positive attributes compared to alternative and more intensive management at a few larger wetland sites.     

A better rationale for wetland management

The present US Federal wetland management strategy under Section 404 of the Clean Water Act does not account for the differences in the natural values of wetlands and their different vulnerability to development pressure. The strategy, aimed at reducing the regulatory burden, provides for different levels of wetland protection, primarily by designating certain activities in or affecting wetlands as essentially harmless, having only minor impacts even when considered for their cumulative effects. Such activities are authorized under general permits precluding any evaluation of project impacts. A sounder, yet practical, rationale for wetland management and regulatory relief should be linked to the scarcity of certain wetland habitats, the habitat diversity or carrying capacity, the degree of degradation from past development, and the incremental losses already incurred within the same wetland ecosystem. The regulatory effort should be concentrated where these characteristics indicate high-value wetlands.Wetland impacts appear to fit into five basic orders of magnitude; these pertain to the relative cost and difficulty of impact mitigation. Up to 13 ecological and public-interest variables can modify the seriousness of the basic impact. Together, the basic orders of impact and modifying variables describe the theoretical framework for wetland management. However, a practical rationale for better wetland management must be constrained to factors not requiring a field investigation in advance of project planning for construction and development.This article was produced in part from work funded by the Office of Technology Assessment (OTA) of the United States Congress for use in its study, Wetlands: Their Use and Regulation. The views expressed do not necessarily represent those of OTA.     

The nature of cumulative impacts on biotic diversity of wetland vertebrates

There is no longer any doubt that cumulative impacts have important effects on wetland vertebrates. Interactions of species diversity and community structure produce a complex pattern in which environmental impacts can play a highly significant role. Various examples show how wetlands maintain the biotic diversity within and among vertebrate populations, and some of the ways that environmental perturbations can interact to reduce this diversity.The trophic and habitat pyramids are useful organizing concepts. Habitat fragmentation can have severe effects at all levels, reducing the usable range of the larger habitat generalists while threatening the genetic integrity of small, isolated populations. The complexity of trophic interactions, and the propensity, or necessity, of vertebrates to switch from one food source to another—something we know little about—makes using food chain support as a variable for predicting environmental impacts very questionable.Historical instances illustrate the effects of the accumulation of impacts on vertebrates. At present it is nearly impossible to predict the result of three or more different kinds of perturbations, although long-range effects can be observed. One case in point is waterfowl; while their ingestion of lead shot, harvesting by hunters during migration, and loss of habitat have caused waterfowl populations to decline, the proportional responsibility of these factors has not been determined.Further examples show multiplicative effects of similar actions, effects with long time lags, diffuse processes in the landscape that may have concentrated effects on a component subsystem, and a variety of other interactions of increasing complexity. Not only is more information needed at all levels; impacts must be assessed on a landscape or regional scale to produce informed management decisions. I conclude that a system of replicate wetland reserves that are allowed to interact naturally with the surrounding landscape will be more effective in preserving biotic diversity than isolated sanctuaries.     

Integrated action planning for biodiversity conservation and sustainable use of highland aquatic resources: evaluating outcomes for the Beijiang River,China

The need for enhanced environmental planning and management for highland aquatic resources is described and a rationale for integrated action planning is presented. Past action planning initiatives for biodiversity conservation and wetland management are reviewed. A reflective account is given of integrated action planning from five sites in China, India and Vietnam. Eight planning phases are described encompassing: stakeholder assessment and partner selection; rapport building and agreement on collaboration; integrated biodiversity, ecosystem services, livelihoods and policy assessment; problem analysis and target setting; strategic planning; planning and organisation of activities; coordinated implementation and monitoring; evaluation and revised target setting. The scope and targeting of actions are evaluated using the Driving forces, Pressures, State, Impacts and Responses framework and compatibility with biodiversity conservation and socio-economic development objectives are assessed. Criteria to evaluate the quality of planning processes are proposed. Principles for integrated action planning elaborated here should enable stakeholders to formulate plans to reconcile biodiversity conservation with the wise use of wetlands.     

An inventory of wetland impoundments in the coastal zone of Louisiana,USA: Historical trends

We inventoried wetland impoundments in the Louisiana, USA, coastal zone from the late 1900s to 1985. Historically, impoundment of wetlands for reclamation resulted in direct wetland loss after levees (dikes) failed and the impounded area was permanently flooded, reverting not to wetland, but to open-water habitat. A current management approach is to surround wetlands by levees and water control structures, a practice termed semi-impoundment marsh management. The purpose of this semi-impoundment is to retard saltwater intrusion and reduce water level fluctuations in an attempt to reduce wetland loss, which is a serious problem in coastal Louisiana. In order to quantify the total impounded area, we used historic data and high-altitude infrared photography to map coastal impoundments. Our goal was to produce a documented inventory of wetlands intentionally impounded by levees in the coastal zone of Louisiana in order to provide a benchmark for further research. We inventoried 370,658 ha within the coastal zone that had been intentionally impounded before 1985. This area is equal to about 30% of the total wetland area in the coastal zone. Of that total area, approximately 12% (43,000 ha) is no longer impounded (i.e., failed impoundments; levees no longer exist or only remnants remain). Of the 328,000 ha still impounded, about 65% (214,000 ha) is developed (agriculture, aquaculture, urban and industrial development, and contained spoil). The remaining 35% (114,000 ha) of impoundments are in an undeveloped state (wetland or openwater habitat). In December 1985, approximately 50% (78,000 ha) of the undeveloped and failed impoundments were open-water habitat. This inventory will allow researchers to monitor future change in land-water ratios that occur within impounded wetlands and thus to assess the utility of coastal wetland management using impoundments.