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981.
综述了河流生物监测的概念、常用指示生物与监测指标、国外相对完善的技术体系及发展趋势。大型底栖动物、着生藻类、鱼类是河流生物监测中最常使用的指示生物,可以单独使用,也可结合使用,详述了这些类群在河流生态系统中的重要地位及用于生物监测的优点。常用的监测指标包括生物多样性指数、生物指数、多参数指数、多变量指数及功能性指数。许多国家和地区(如英国、美国、欧盟等)都已经将生物监测纳入水环境管理系统,并开发出自己的技术体系。未来的河流生物监测中,功能性指数的应用会越来越多,分子技术的介入也会为提高分类辨识度和检测遗传多样性提供更为有效的途径。最后,思考并总结了国内河流生物监测的现状及趋势。  相似文献   
982.
生态补偿的概念自提出便受到学界和政府决策者的广泛关注,并迅速成为近20年来生态保护的主要政策手段。虽然基于生态补偿的政策手段被大范围使用,但是生态补偿的相关理论却处于发展与争论的阶段,该理论的适用性及对现实问题的剖析在实践过程中备受质疑。本文梳理了生态补偿理论发展及构建的过程,将其总结为生态系统服务概念的提出、生态系统服务价值评估方法的建立、以及生态系统服务市场机制的构建三个主要阶段。已有研究更多集中在生态补偿的具体实施层面,如补偿标准、补偿方式、效果评估等方面,但是对基础理论探讨不足。本文从生态补偿理论发展及构建的三个过程,综述了目前对生态补偿理论的讨论及争议,认为在处理"社会—生态"关系的核心问题上,尤其在一些长期依赖并利用自然资源的传统地区或者民族地区,目前学术界和政策决策者均对此问题缺乏深入的理解,这也是实践中生态补偿政策未达到理想效果的主要原因之一。最后,本文提出用"社会生态系统服务"一词代替目前所使用的"生态系统服务",这一概念有助于在理论上避免忽视社会系统及社会与生态系统二者之间的关系,减少不当外部政策干预。  相似文献   
983.
Land use change can significantly affect the provision of ecosystem services and the effects could be exacerbated by projected climate change. We quantify ecosystem services of bioenergy‐based land use change and estimate the potential changes of ecosystem services due to climate change projections. We considered 17 bioenergy‐based scenarios with Miscanthus, switchgrass, and corn stover as candidate bioenergy feedstock. Soil and Water Assessment Tool simulations of biomass/grain yield, hydrology, and water quality were used to quantify ecosystem services freshwater provision (FWPI), food (FPI) and fuel provision, erosion regulation (ERI), and flood regulation (FRI). Nine climate projections from Coupled Model Intercomparison Project phase‐3 were used to quantify the potential climate change variability. Overall, ecosystem services of heavily row cropped Wildcat Creek watershed were lower than St. Joseph River watershed which had more forested and perennial pasture lands. The provision of ecosystem services for both study watersheds were improved with bioenergy production scenarios. Miscanthus in marginal lands of Wildcat Creek (9% of total area) increased FWPI by 27% and ERI by 14% and decreased FPI by 12% from the baseline. For St. Joseph watershed, Miscanthus in marginal lands (18% of total area) improved FWPI by 87% and ERI by 23% while decreasing FPI by 46%. The relative impacts of land use change were considerably larger than climate change impacts in this paper. Editor's note : This paper is part of the featured series on SWAT Applications for Emerging Hydrologic and Water Quality Challenges. See the February 2017 issue for the introduction and background to the series.  相似文献   
984.
为评估嘧菌酯·噻呋酰胺4%展膜油剂在我国稻田水溢出对水生生态系统的风险,本研究依据中华人民共和国农业行业标准NY/T 2882.2—2016《农药登记环境风险评估指南第2部分:水生生态系统》,采用TOP-RICE暴露模型分别单独评估了嘧菌酯和噻呋酰胺2种有效成分稻田滴撒方式应用时水溢出对水生生态系统的风险。其中,TOP-RICE初级暴露模型中有我国连平和南昌2个水稻-地下水暴露场景,每个场景都对分蘖期和拔节期进行分别评估。分析结果显示,嘧菌酯·噻呋酰胺4%展膜油剂中的嘧菌酯按照申请的良好农业规范(GAP)使用,生物富集风险可接受,初级风险评估对无脊椎动物(急性)和无脊椎动物(慢性)风险不可接受,但经中宇宙研究后,在连平和南昌2个场景点,均为拔节期用药对无脊椎动物的风险可接受,但分蘖期用药对无脊椎动物的风险不可接受;嘧菌酯·噻呋酰胺4%展膜油剂中的噻呋酰胺按照申请的GAP使用,生物富集带来的风险可以接受,经初级风险评估风险均可接受。在忽略2种有效成分相互间作用时,初步认为嘧菌酯·噻呋酰胺4%展膜油剂在我国稻田拔节期按照GAP要求施用时水溢出对水生生态系统的风险可接受,但应避免在分蘖期用药,以免其中的有效成分嘧菌酯对水生无脊椎动物产生不良影响。  相似文献   
985.
基于2000/2005/2010年三期土地利用现状遥感监测数据,利用GIS空间分析技术,分析长江流域土地利用变化方式、过程、区域特征和生态系统服务功能变化。研究表明:2000~2010年长江流域城乡建设用地、林地和水域面积增长显著,而耕地、草地面积持续减少;耕地减少和城乡建设用地增加相关,草地减少和林地增加相关,水域增加与三峡蓄水及退田还湖相关;四川盆地、中游城市群和长三角城市群等人类活动热点区域的土地利用程度显著提高;受土地利用变化影响,2000~2010年长江流域生态系统服务总价值逐年提高,水源涵养、废物处理和娱乐文化服务功能增强,而土壤形成与保护、食物生产服务功能明显减弱;生态服务价值高值区主要分布在沿江湖泊和湿地,其次是林草地覆盖区,青海高原荒漠区生态服务价值最低。  相似文献   
986.
Traditional approaches for evaluating aesthetic value rely on surveys or interviews. Social media provides a new type of crowdsourcing data to examine the relationships between aesthetic value and citizens' activities. The main goal of this paper was to evaluate aesthetic value in Nebraska by using citizen-reported geo-tagged photographs posted on two social media sites – Panoramio and Flickr. The study used the application programming interface from Panoramio and Flickr to obtain the latitude and longitude of the geo-tagged photographs, and then used ArcGIS spatial statistical tools to examine spatial patterns with areas of aesthetic value in Nebraska. The outcomes identified the clusters of pictures with the locations of ecosystem service provisioning areas of aesthetic value in Nebraska, identified new areas with aesthetic value, and drew comparisons with local and regional population distribution. This study provided an innovative approach to using crowdsourcing data to verify the value of ecosystem services.  相似文献   
987.
Abstact Aboveground biomass, aboveground litterfall, and leaf litter decomposition of five indigenous tree stands (pure stands ofPinus brutia,Pinus nigra,Cedrus libani,Juniperus excelsa, and a mixed stand ofAbies cilicica,P. nigra, andC. libani) were measured in an eastern Mediterranean evergreen needleleaf forest of Turkey. Measurements were converted to regional scale estimates of carbon (C) stocks and fluxes of forest ecosystems, based on general non-site-specific allometric relationships. Mean C stock of the conifer forests was estimated as 97.8± 79 Mg C ha−1consisting of 83.0 ± 67 Mg C ha−1in the aboveground and 14.8 ± 12 Mg C ha−1in the belowground biomass. The forest stands had mean soil organic carbon (SOC) and nitrogen (SON) stocks of 172.0 ± 25.7 Mg C ha−1and 9.2 ± 1.2 Mg N ha−1, respectively. Mean total monthly litterfall was 376.2± 191.3 kg C ha−1, ranging from 641 ± 385 kg C ha−1forPinus brutiato 286 ± 82 kg C ha−1forCedrus libani. Decomposition rate constants (k) for pine needles were 0.0016 forCedrus libani, 0.0009 forPinus nigra, 0.0006 for the mixed stand, and 0.0005 day−1forPinus brutiaand Juniperus excelsa. Estimation of components of the C budgets revealed that the forest ecosystems were net C sinks, with a mean sequestration rate of 2.0 ± 1.1 Mg C ha−1 yr−1ranging from 3.2 ± 2 Mg C ha−1forPinus brutiato 1.6 ± 0.6 Mg C ha−1forCedrus libani. Mean net ecosystem productivity (NEP) resulted in sequestration of 98.4 ± 54.1 Gg CO2 yr−1from the atmosphere when extrapolated for the entire study area of 134.2 km2(Gg = 109 g). The quantitative C data from the study revealed the significance of the conifer Mediterranean forests as C sinks  相似文献   
988.
The Northern River Ecosystem Initiative (NREI), 1997–2004, has provided new scientific knowledge in response to specific recommendations from its predecessor, the Northern River Basins Study (NRBS), 1990–1996. The two initiatives together provide a remarkable body of science which is, and will continue to be, used by resource managers responsible for economic and environmental sustainability in the northern watersheds of Alberta. The NREI focused its investigative efforts on improving our understanding related to ecological considerations of changes in river flow, effect of climate change on flow, ecological responses to pollution and cumulative effects, vulnerability of drinking water quality, and to a lesser degree, wildlife (birds) response to large scale changes within the watersheds. Key findings are briefly presented in this paper and discussed in greater detail in the other NREI papers included in this. Commensurate with the undertakings of NREI, provincial and territorial governments, First Nation and Métis communities, and other administrative organizations such as the Mackenzie River Basin Board, undertook policy, regulatory, and watershed initiatives towards achieving sustainability and providing reliable drinking water quality.  相似文献   
989.
This paper provides a comparison of ecosystem management (EM) to the traditional regulatory management approach and outlines the characteristics of EM from a policy perspective, defining the conditions under which this management tool can be successfully implemented. Ecosystem management is a collaborative and integrative tool focused on balancing societal needs, economic growth, and environmental protection to ensure the long-term ecological integrity of a particular ecosystem. The characteristics of this particular tool include: (1) its holistic approach to environmental problems; (2) its integration of values (economic, social, and environmental) through a collaborative, multi-partner, decision making structure; (3) its reliance on science to guide decisions and set boundaries; and (4) its ability to learn from the implementation of decisions (adaptive management). Examples are draw from Environment Canada's various regional ecosystem initiatives.  相似文献   
990.
Unprecedented rates of human-induced changes in land use and land cover (LULC) at local and regional scales lead to alterations of global biogeochemical cycles. Driving forces behind LULC changes mainly include rapid growth rates of population and consumption, lack of valuation of ecological services, poverty, ignorance of biophysical limitations, and use of ecologically incompatible technologies. One of the major ecological tragedies of the commons in a Mediterranean region of Turkey is the loss of Lake Amik at the expense of increasing the area of croplands, which used to provide vital ecosystem goods and services for the region. In this study, we aimed at quantifying the effects of past land-use transitions on soil organic carbon (SOC) pools (0–20 cm) in a Mediterranean region of 3930 km2, between 1972 and 2000. LULC changes were quantified from a time series of satellite images of Landsat-MSS in 1972, Landsat-5 TM in 1987, and Landsat-7 ETM+ in 2000 using geographic information systems. The study showed that the increase in croplands between 1972 and 1987 took place at the expense of the irreversible losses of Lake Amik and its related wetlands of over 53 km2. In the period of 1972 to 2000, croplands, settlements, and evergreen forests increased by 174%, 106%, and 14%, respectively. The increase in settlements occurred mostly to the detriment of croplands. Given the average rates of all the land-use transitions, and associated changes in SOC density for the study region of 3930 km2, total SOC pool was estimated to decrease by 14.1% from 130.1 Mt in 1972 to 111.7 Mt in 2000.  相似文献   
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