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891.
The natural wetlands in the Changjiang Estuary, China are important ecologically. The total area of the wetlands in the Changjiang Estuary amounts to 215000 ha. The wetlands consist of littoral and sandy estuarine island areas, and are rich in biological resources. There are 136 species of vascular plant, 150 species of bird, and 68 species of benthic macro-invertebrate in the wetlands. However, the wetland in the Changjiang Estuary is a vulnerable ecosystem. Development of the wetland is mainly influenced by intensive human reclamation, pollution, movement of sediments in the Changjiang River, and the effects of tides and waves. Investigations have shown that maintaining biodiversity, providing resources for the living organisms, purifying environments and resisting natural hazards could be regarded as important functions for the protection of the wetlands. It is proposed that sustainable principles should be supported in developing the wetlands in the future.  相似文献   
892.
The right to eat and to an adequate standard of living for everyone motivates agricultural research assistance to developing countries with the primary objective of assuring sufficient food supply. This article focuses on aspects of food production and related agricultural research with specific examples from animal production. It discusses ethics of agricultural research in light of the utilitarian theory and compares livestock production in developing and developed countries. Major reasons for low outputs of animal production in developing countries are identified, and the potential for increasing the productivity of original, extensive production systems is evaluated. The article reviews the current status of biotechnology in developing countries and discusses several advanced animal technologies. The conclusions emphasize the need to involve local professionals in all phases of research and technology transfer in developing countries, avoidance of research that may worsen the situation of the recipients, sustainability of production systems, and the need for detailed assessment of potential impacts of technology on recipients.  相似文献   
893.
By combining economic analysis of markets with ecological parameters, this article considers the role that tourism-based sea turtle hatcheries (of an open-cycle type) can play in conserving populations of sea turtles. Background is provided on the nature and development of such hatcheries in Sri Lanka. The modeling facilitates the assessment of the impacts of turtle hatcheries on the conservation of sea turtles and enables the economic and ecological consequences of tourism, based on such hatcheries, to be better appreciated. The results demonstrate that sea turtle hatcheries serving tourists can make a positive contribution to sea turtle conservation, but that their conservation effectiveness depends on the way they are managed. Possible negative effects are also identified. Economic market models are combined with turtle population survival relationships to predict the conservation impact of turtle hatcheries and their consequence for the total economic value obtained from sea turtle populations.  相似文献   
894.
Recent attention has focused on resource management initiatives at the watershed scale with emphasis on collaborative, locally driven, and decentralized institutional arrangements. Existing literature on limited selections of well-established watershed-based organizations has provided valuable insights. The current research extends this focus by including a broad survey of watershed organizations from across the United States as a means to estimate a national portrait. Organizational characteristics include year of formation, membership size and composition, budget, guiding principles, and mechanisms of decision-making. These characteristics and the issue concerns of organizations are expected to vary with respect to location. Because this research focuses on organizations that are place based and stakeholder driven, the forces driving them are expected to differ across regions of the country. On this basis of location, we suggest basic elements for a regional assessment of watershed organizations to channel future research and to better approximate the organizational dynamics, issue concerns, and information needs unique to organizations across the country. At the broadest level, the identification of regional patterns or organizational similarities may facilitate the linkage among organizations to coordinate their actions at the much broader river basin or ecosystem scale.  相似文献   
895.
Future sustainability of the conservation management of socio-ecological landscapes is typically reliant on on-going agricultural management. Such management may be threatened by changes in the drivers of management and the fragility of the stakeholder networks that deliver management. This study examined evidence for the risk of abandonment in a series of case study high nature value (HNV) grassland sites. The work found that the motivation of farmers to participate in the conservation management was typically limited and often marginal. Landowners and conservation stakeholders who relied on partner farmers to manage such sites often struggled to recruit and retain their participation, leading to increased turnover among managing farmers and to some sites being under-managed. Primary reasons for difficulty of recruitment and farmer turnover included a lack of candidate farmers in the local landscape, and the marginal and fluctuating economics of grassland management. A trend towards greater financial incentivisation of farmers was evident, which policy-makers responsible for agri-environment schemes should note, and elsewhere some conservation organisations were seen to be bringing grassland management in-house. Farmers’ motivations to participate in conservation management of such systems may continue to weaken and abandonment may therefore become a significant risk to the successful conservation of such systems. Conservation stakeholders need to foster good relations with their farmer-manager partners and not further depress their limited motivations to participate, as well as consider carefully whether farmer stakeholders are being adequately compensated for their efforts.  相似文献   
896.
长江三角洲耕地资源态势与保护对策   总被引:13,自引:7,他引:13  
长江三角洲是我国东部沿海经济最发达的地区,在全国占有十分重要的经济地位。随着经济的发展,资源与环境发生了严重的问题,特别是近年来耕地资源锐减,而后备耕地资源却短缺,人地人粮矛盾更加尖锐,已成为影响这一地区农业持续发展的重要因素。本文分析了这一地区的经济特点与耕地资源的变化态势,并提出了相应的耕地保护措施。首先,要严格控制非农用地,确保基本农田,其次要采用经济手段,建立保护耕地的经济机制;此外,还要  相似文献   
897.
通过对广东连州地区植物资源的考查和研究,发现该地区有珍稀濒危植物31科42唐45种,其中国家一级保护植物4种,国家二级保护植物27种。对它们的种类组成、区系成分、分布特征进行了分析,结果显示这些珍稀濒危植物具有组成多样、亚热带性质明显、起源古老、特有现象突出等特点,分析了这些植物濒危的原因,提出了相应的保护对策。  相似文献   
898.
Use of Traditional Ecological Knowledge in Marine Conservation   总被引:6,自引:0,他引:6  
Abstract:  Traditional ecological knowledge (TEK) represents multiple bodies of knowledge accumulated through many generations of close interactions between people and the natural world. TEK and its application via customary ecological management plans can be useful in modern conservation programs. I disaggregate the term TEK into its constituent parts and show several ways in which TEK can strengthen research designs by increasing locality-specific knowledge, including environmental linkages occurring in those localities. Examples of the uses of TEK in conservation include folk taxonomy in systematics in Micronesia, species knowledge for conservation in Kiribati, and fishers' knowledge of ecological interactions for reserve design in Belize. When conservationists recognize the utility of TEK, they can engage in an equitable exchange of knowledge and foster shared responsibility with indigenous people. These types of exchanges can also provide an opportunity for indigenous people to develop a scientific infrastructure.  相似文献   
899.
ABSTRACT: Soil erosion is the most significant threat to land productivity and environmental quality on the Loess Plateau of China. The annual total sediment load of the Yellow River is 1.6 billion tons, with about 90 percent coming from soil erosion from the Loess Plateau. To reduce soil erosion from the Loess Plateau, conservation practices, including tree planting, ridge construction between fields and around gullies, terrace and ditch construction perpendicular to the main slope, and dam construction are being implemented. An evaluation of these conservation practices is required before they are implemented at the large scale. The objective of this study is to evaluate the effectiveness of conservation practices to control runoff and sediment yield from paired watersheds in the hilly gully region of the Loess Plateau. The advantage of the paired watershed approach is its sensibility in detecting differences in runoff and sediment transport by monitoring both watersheds during two periods, an initial period with no conservation practices and a treatment period with only one watershed subjected to conservation practices. Implementation of the conservation practices resulted in (1) cumulative runoff and sediment yield that were, respectively, 25 and 38 percent less from the treatment watershed than from the control, (2) a decrease in the number of rainfall events producing runoff and sediment transport (94 in the control versus 63 in treatment), and (3) a reduction in the maximum discharge and maximum suspended sediment concentration.  相似文献   
900.
ABSTRACT: Assessment and control of nutrient losses from paddy fields is important to protect water quality of lakes and streams in Korea. A four‐year field study was carried out to investigate water management practices and losses of nitrogen (N) and phosphorus (P) in rice paddy irrigation fields in southern Korea. The amount and water quality of rainfall, irrigation, surface drainage, and infiltration were measured and analyzed to estimate inputs and losses of N and P. The observed irrigation amount surpassed consumptive use, and approximately 52 to 69 percent of inflow (precipitation plus irrigation) was lost to surface drainage. Field data showed that significant amounts of irrigation water and rainfall were not effectively used for rice paddy culture. Water quality data indicated that drainage from paddy fields could degrade the recipient water environment. The nutrient balance indicated that significant amounts of nutrients (29.5 percent of total N and 8.6 percent of total P compared to input) were lost through surface drainage. Furthermore, up to half the nutrient losses occurred during nonstorm periods. The study results indicate that inadequate water management influences N and P losses during both storm and nonstorm periods. Proper water management is required to reduce nutrient losses through surface drainage from paddy fields; this includes such measures as minimum irrigation, effective use of rainfall, adoption of proper drainage outlet structures, and minimized forced surface drainage.  相似文献   
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