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1.
黑河流域土地利用变化对生态系统服务价值的影响 总被引:21,自引:4,他引:21
利用1987年和2000年1:100000Landsat TM图像解译数据分析了黑河流域土地利用变化,在此基础上,采用中国陆地生态系统服务价值的测算方法,评估了黑河流域土地利用变化引起的生态环境质量变化。结果表明,在过去的13年间,黑河流域土地利用变化总的趋势是森林、草地、河流冰川面积大幅减少,耕地、盐碱地和建筑用地迅速增加。这一变化损害了该区域的生态系统服务功能,使生态系统服务总价值(人民币)从404.22亿元/a下降到370.3亿元/a,损失率达到了8.39%。 相似文献
2.
桉树人工林间种山毛豆,增加了凋落物量和养分归还量,改善了营养元素的生物小循环。在一个轮伐期内山毛豆归还土壤养分的数量如下:氮528.37kg/hm^2,磷28.06kg/hm^2,钾66.20kg/hm^2,钙184.96kg/hm^2,镁57.21kg/hm^2;而同期刚果W5桉归还土壤养分的数量为:氮85.98kg/hm^2,磷3.94kg/hm^2,钾11.80kg/hm^2,钙36.98kg/hm^2,镁18.30kg/hm^2。由于间种山毛豆增加了生态系统的养分收入,减少了水土流失的养分支出,系统的各种养分出现了盈余的状况。 相似文献
3.
桉树人工林生态系统养分循环和平衡研究Ⅱ. 桉树人工林生态系统的养分循环 总被引:1,自引:4,他引:1
根据大量的观测分析资料,论述了刚果W5桉树人工林生态系统养分的地球化学循环和生物小循环。研究结果表明,每公顷每年通过地表径流和地下渗漏从生态系统输出的养分质量以K最多,达21.25 kg/(hm2a);其次为N,达17.21 kg/(hm2a)。桉树人工林生态系统养分流通质量的净变化值f(K)、f(Ca)为负值,f(N)、f(P)、f(Mg)为正值;桉树人工林生态系统养分的生物小循环研究表明,在一个轮伐期内,每公顷桉树吸收养分的质量,依次为Ca 429.03 kg/hm2,其次为N 277.01 kg/hm2和K 208.12 kg/hm2。而在一个轮伐期中归还的养分质量,Ca只有99.78 kg/hm2,K为113.04 kg/hm2。在养分循环率方面,与热带半落叶季雨林比较,桉树人工林生态系统的养分循环率要小得多,说明桉树人工林土壤养分趋向于减少。 相似文献
4.
桉树人工林生态系统养分循环与平衡研究Ⅰ. 桉树人工林生态系统的养分贮存 总被引:8,自引:5,他引:8
采用田间试验和定位方法,在标准样地中研究养分的输入、输出和贮存。桉树人工林生态系统的养分贮存,包括土壤、桉树林分和凋落物三者贮存的养分。在田间试验的基础上,获得了大量的分析数据。论述了刚果W5桉树人工林生态系统土壤养分的贮存量、林分的养分贮存量和凋落物层的养分贮存量以及上述分系统内大、中量元素的含量比例。土壤养分的贮存量,全量养分以K最多,其次为N、P;有效养分贮存量大小的顺序为N,K,Ca,P,Mg,Mn,Zn,Cu,B。桉树林分的总养分贮存量,是逐年增加的,但以第2年的增量最大;各元素贮量大小,则每年不同。凋落物层的养分贮存量,总体上逐年增长,但以第4年最多;各元素贮存量大小的顺序为N,Ca,Mg,K,P。这些结果,对于指导桉树施肥,有重要的参考价值。 相似文献
5.
桉树人工林生态系统养分循环和平衡研究Ⅲ. 桉树人工林生态系统的养分平衡 总被引:6,自引:5,他引:6
在当地现行的生产技术规程和营林措施的条件下,刚果W5桉树人工林生态系统中,N和K的收支帐为亏损,P、Ca、Mg为盈余。在一个轮伐期内,每公顷养分质量的收入中,N为327.13kg/hm^2,P为110.48kg/hm^2,K为206.13kg/hm^2。,Ca为679.53kg/hm^2,Mg为173.72kg/hm^2;每公顷养分质量的支出中,N为366.59kg/hm^2,P为35_3lkg/hm^2,K为212.22kg/hm^2,Ca为452.77kg/hm^2,Mg为79.52kg/hm^2。但这仅仅是一种表观数字。桉树人工林生态系统养分不平衡的主要原因,是桉树凋落物和采伐剩余物不能回归土壤,以及严重的水土流失。解决问题的关键是转变思想认识,制定有效的措施,使桉树凋落物和采伐剩余物回归土壤,同时在桉树行间间种豆科绿肥牧草。 相似文献
6.
水电开发对河流生态系统服务功能影响的价值评估初探 总被引:5,自引:1,他引:5
提出了计算“流量”,即计算受水电开发影响的河流生态系统服务功能的价值变化量的评估思路和方法,并以广东省河源市风光水利枢纽工程为案例进行了定量分析。在对河流生态系统服务功能进行分类的基础上,根据河流生态系统服务功能可能受到水电开发影响的现实情况和影响特征,选择适当的生态系统服务功能价值核算的方法和参数,计算受影响的生态系统服务功能的价值变化量。案例研究结果表明,风光水利枢纽工程开发方案引起的河流生态服务功能价值变化的正效益为7 676万元/a,负效益为-3 894万元/a,负效益占到其正效益的一半以上,说明该工程开发对东江河流生态系统的消极负面影响也是不容忽视的,应采取适当的生态补偿措施。 相似文献
7.
Serdar Eyeberenov Baijing Cao Fengting Li 《Frontiers of Environmental Science & Engineering》2009,3(2):221-225
Prior to independence, Central Asian countries were closely interconnected through the regional management incorporating water, energy, and food sectors. This approach, supported by the central government of Union of Soviet Socialist Republics (USSR), functioned effectively — meeting the needs of both upstream and downstream countries. However, after independence, Central Asian countries started prioritizing their own economic development policies without due account to regional concerns such as joint use of water resources, leading to instability. In this study, the case of Syrdarya basin was investigated to show how such strategies create tension in the region, since primary focus is given to national interests, without consideration for regional problems. To address this issue, an integrated approach to incorporating water, energy, and agriculture is needed. It is suggested that a single sector approach on water alone does not lead to stability, and a multi-sectoral approach is necessary to ensure sustainable development. Countries sharing benefits from the river have to be responsible for costs of operation and maintenance of the water facilities. 相似文献
8.
Integrating wetlands and riparian zones in river basin modelling 总被引:1,自引:0,他引:1
Wetlands, and in particular riparian wetlands, represent an interface between the catchment area and the aquatic environment. They control the exchange of water and related chemical fluxes from the upper catchment area to surface waters like streams and lakes. Their influence on water and nutrient balances has been investigated mainly at the patch scale. In this study an attempt was made (a) to integrate riparian zones and wetlands into eco-hydrological river basin modelling, and (b) to quantify the impacts of riparian wetland processes on water and nutrient fluxes in a meso-scale catchment located in the northeastern German lowland. The investigation was performed by analysing hydro-chemical field data and applying the eco-hydrological model SWIM (Soil and Water Integrated Model), which was extended to reproduce the relevant water and nutrient flows and retention processes at the catchment scale in general, and in riparian zones and wetlands in particular. The main extensions introduced in the model were: (1) implementation of daily groundwater table dynamics at the hydrotope level, (2) implementation of water and nutrient uptake by plants from groundwater in riparian zones and wetlands, and (3) assessment of nutrient retention in groundwater and interflow. The simulation results indicate that wetlands, though they represent relatively small parts of the total catchment area, may have a significant impact on the overall water and nutrient balances of the catchment. The uncertainty of the simulation results is considerably high, with the main sources of uncertainty being the model parameters representing the geo-hydrology and the input data for land use management. 相似文献
9.
流域生态补偿理论探讨 总被引:2,自引:0,他引:2
流域生态补偿是协调流域生态环境保护和经济发展之间矛盾,调整流域内区域间损益关系的有效手段。文章从流域内人类活动产生的损益人手,论述了流域生态补偿的概念、理论基础和运行机铷,并利用经济学原理,对生态补偿的必要性和补偿标准进行了理论解析,给出了流域生态补偿必要性的理论依据和需要补偿量的理论值。在此基础上,根据流域人类活动的正负外部性等原则,对流域生态补偿进行了分类。依据流域生态补偿分类,梳理出了我国流域生态补偿重点区域。通过对流域生态补偿理论探讨,以期作为进一步研究和应用实践的参考和启示。 相似文献
10.
The fresh water reaching an estuary fluctuates on many scales and the fluctuation in the flow over a time period is also due to the anthropogenic activities like construction of dams, diversions and upstream withdrawals. These fluctuations may have profound effects on the estuarine ecosystem, which usually has remarkable biological productivity and diversity. A desktop analysis is carried out by compiling historical records of discharge and other hydrological information to study the dynamics of the river Coleroon, a distributary of the Cauvery River, Tamil Nadu, India. Remote sensing analysis was carried out on images ranging from the years 1977 to 2008 and the changes in the Pichavaram mangrove areas adjoining the Coleroon were studied by comparing the results with the freshwater flow into the ecosystem. Environmental flow analysis indicates that the minimum flow needed for a healthy mangrove system in Pichavaram is 750.75 cumecs; however, this is currently achieved only 12 % of the time. The reduction in freshwater flow over the years has resulted in loss of species diversity and degradation of the mangroves; this needs to be corrected immediately to conserve the Pichavaram mangrove ecosystem. 相似文献