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新疆奎屯河水文特征分析 总被引:2,自引:0,他引:2
依据奎屯河1972~2006年的水文统计资料对河流水文特征进行了初步分析,结果表明:奎屯河属于多泥沙的季节性河流,流域降水稀少,蒸发旺盛;河流主要以冰川融雪水为补给源;正常径流量为6.18×108m3,径流年内分配不均,集中度高,年际变化相对稳定,变幅较小;水质为中性,矿化度不高。 相似文献
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依据奎屯河1972~2006年的水文统计资料对河流水文特征进行了初步分析,结果表明:奎屯河属于多泥沙的季节性河流,流域降水稀少,蒸发旺盛;河流主要以冰川融雪水为补给源;正常径流量为6.18×108m3,径流年内分配不均,集中度高,年际变化相对稳定,变幅较小;水质为中性,矿化度不高。 相似文献
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河流生态健康评价不仅可以客观评价河流生态系统现状,还有助于决策者确定河流的管理活动,对于流域可持续开发和管理、产业结构合理布局、实现环境功能目标等具有重要意义。选取云南牛栏江为研究河流,采用多指标法对生态健康状况进行综合评价,分析影响河流生态健康的现存环境问题,并从开展河道治理及生态修复、推进农村农业面源污染整治、加大工业水污染源治理力度、加快流域陆域生态建设步伐、构建流域综合管理体系网络、划定并严守流域生态保护红线等方面,提出了生态健康保护对策,以期维护流域生态功能、逐步恢复河流水质、有效减缓生态压力,为其他河流生态健康发展提供借鉴。 相似文献
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食物链长度是生态系统的基本属性,其变化决定着群落结构和生态系统功能。稳定同位素分析技术的进步推进了生态系统中食物链长度决定因子相关研究的开展。尽管近期的研究证明了食物链长度与资源可利用性、生态系统大小、干扰等远因之间的关系,但是对于食物网内部结构变化这一近因对食物链长度的影响作用关注较少。综述了边界明确和开放类型淡水生态系统中食物链长度的相关研究进展;探讨了远因和近因机制在决定食物链长度中的作用;给出了判断不同层次和尺度上决定食物链长度机制的概念框架;为今后更好的开展不同生态系统间食物链长度的比较研究提出了建议。 相似文献
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随着我国城市化进程的加快,城市生态环境面临着越来越严峻的考验,为了促进城市的可持续发展,构建城市绿地生态网络、维护城市生态系统的稳定性成为众多领域研究的重点。河流作为城市绿地生态网络的核心空间结构,开放空间作为绿地生态网络的基础,二者关系的研究对构建城市绿地生态网络具有重要意义。在研究河流与开放空间耦合关系的基础上,结合对城市绿地生态网络含义、功能机制、评价指标的分析,以南阳市为例,提出河流与开放空间耦合的城市绿地生态网络构建方法。 相似文献
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西南大西洋是世界重要的渔区之一,捕捞国家包括阿根廷等西南大西洋沿海国以及中国、日本等众多非沿海国家,其中阿根廷滑柔鱼(Illex argentinus)、阿根廷无须鳕(Merluccius hubbsi)、巴西小沙丁鱼(Sardinella brasiliensis)与弗氏绒须石首鱼(Micropogonias furnieri)是西南大西洋年均产量最高的4种主要经济渔获物。探究气候变化对西南大西洋生态系统的影响有利于建立基于生态系统的渔业资源保护与利用格局。本文从渔业资源与生态系统两个角度出发,分别归纳了生态系统的生物因子(主要经济渔获物)、非生物因子(环境因素)与营养结构(食物链和食物网)对气候变化的响应情况。分析认为,在今后探究西南大西洋生态系统对气候变化的响应的研究中,选取代表物种表征生态系统的变化并结合人类活动与气候变化的影响可以丰富生态系统的相关结论,为西南大西洋海域提供基于生态系统的科学管理策略。 相似文献
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目前,水利工程对于天然河流造成的不利影响已经受到了社会各界的关注。从河流生态系统的特点出发,分析水利工程对于河流的生态系统造成了哪些胁迫。 相似文献
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河道作为城市生态系统的重要组成部分,其污染问题受到了普遍关注.近年来,全国掀起了城市河道治理的热潮,一些城市的点源污染已得到控制,黑臭现象基本消除,城市河道面貌初步改观.在点源污染得到控制的基础上,面源污染的控制和生态系统的恢复逐渐成为河流研究的热点和治理城市河道的大趋势.综述了目前国内外主要应用的河道生态修复技术,提出必须结合多种河道修复技术,并且从流域尺度进行河道的生态系统恢复. 相似文献
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Ecologists have long been studying stability in ecosystems by looking at the structuring and the strengths of trophic interactions in community food webs. In a series of real food webs from native and agricultural soils, the strengths of the interactions were found to be patterned in a way that is important to ecosystem stability. The patterning consisted of the simultaneous occurrence of strong "top down" effects at lower trophic levels and strong "bottom up" effects at higher trophic levels. As the patterning resulted directly from the energetic organization of the food webs, the results show that energetics and community structure govern ecosystem stability by imposing stabilizing patterns of interaction strengths. 相似文献
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五里湖生态系统能量流动模型初探 总被引:3,自引:0,他引:3
根据2009年五里湖的渔业资源和生态环境调查数据,利用EwE 6.0构建五里湖生态系统的生态通道模型。该模型包括大型鲌、其他食鱼性鱼类、湖鲚、鲤、鲫、野杂鱼、鲢、草食性鱼类、大型虾蟹类、软体动物、其他底栖动物、浮游动物、沉水植物、其他维管束植物、浮游植物和碎屑等17个功能组,基本覆盖了五里湖生态系统能量流动的主要过程。模型分析表明:2009年五里湖生态系统处在趋于成熟时期。生态网络分析表明,生态系统各功能组的营养级范围为1~3.958,能量流动主要有6级,来自初级生产者的能量效率为4.4%,来自碎屑的传递效率为5.1%,平均能量传递效率为4.9%。生态系统功能组直接来源于碎屑的比例占总流量的60%,来源于初级生产者的比例为44%。生态系统的总初级生产计算量/总呼吸量(TPP/TR)、连接指数(CI)、系统聚合度(A)、Finn′s循环指数(FCI)、Finn′s平均能流路径长度(FCL )和系统杂合度(SOI)分别为1.339、0.277、0.267、0.155、3.393、0.119。 相似文献
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基于Ecopath的热带东太平洋生态系统模型构建及其比较 总被引:3,自引:2,他引:1
建立2017年东太平洋生态系统Ecopath模型,并与1997年模型进行比较。结果表明:(1)生态系统总体能量转化效率为18.78%,表明该生态系统能量的利用效率已达到最适程度。生态系统杂食指数和联结指数分别为0.323和0.272,表明功能组的聚合度较低,食物网内部结构复杂程度较低,较易受到外界环境因素和捕捞的干扰。总初级生产量与总呼吸量的比值为2.593,表明该生态系统不成熟。(2)对比两个阶段的系统总流量、总生物量以及总循环流量指标,与1997年相比,2017年生态系统规模扩大,食物网复杂程度升高,成熟度增大但仍然处于发展阶段。(3)假设黄鳍和大眼金枪鱼这两个主要捕捞种类的大、小个体相对资源量统计存在不确定性,并考虑3个比例水平分别构建3个生态系统模型,结果表明,这一相对资源量统计误差,明显影响了对生态系统的认识。因此,在今后类似的研究中,应充分考虑主要捕捞种类不同体长组的营养结构及其对生态系统的影响。 相似文献
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Beef with environmental and quality attributes: Preferences of environmental group and general population consumers in Saskatchewan, Canada 总被引:1,自引:0,他引:1
We attempt to quantify and qualify the preferences of consumers for beef with a number of environmental and food quality attributes.
Our goal is to evaluate the viability of a proposed food co-operative based in the Wood River watershed of southern Saskatchewan,
Canada. The food co-operative was designed to provide a price premium to producers who adopted alternative management practices.
In addition, the study evaluated the acceptance of a proposed food co-operative by consumer that had environmental interests
as compared to the general population. Conjoint analysis was used to determine the trade-off and relative value of beef with
the following production and purchasing characteristics: (a) use of hormones, antibiotics and vaccination in production; (b)
method of obtaining the beef including monthly or yearly purchase contracts or a local market; (c) price relative to beef
purchased from the local grocery store; and (d) impact on the river ecosystem. Consumers from environmental groups had stronger
environmental and food quality preferences than individuals from the general population. However, consumers from both groups
expressed a willingness to pay higher prices for food that had these attributes. It was uncertain whether the magnitude of
the premium, in combination with a desire not to enter a long-term purchasing commitment, would be large enough to encourage
farmers to adopt the alternative management.
Ken W. Belcher is an Associate Professor in the Department of Agricultural Economics at the University of Saskatchewan. His research has
focused on ecological economics and environmental policy with a particular interest in environmental conservation in agricultural
landscapes.
Andrea E. Germann was a Research Assistant with the Centre for Studies in Agriculture, Law and the Environment at the University of Saskatchewan.
Josef K. Schmutz is a Research Fellow with the Centre for Studies in Agriculture, Law and the Environment. Joe has expanded his research interest
on prairie raptors by fostering strategic design for alternative, local economies that include the conservation of birds and
their ecosystems. 相似文献
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The small-watershed approach to problems of nutrient cycling has these advantages. (i) The small watershed is a natural unit of suitable size for intensive study of nutrient cycling at the ecosystem level. (ii) It provides a means of reducing to a minimum, or virtually eliminating, the effect of the difficult-to-measure variables of geologic input and nutrient losses in deep seepage. Control of these variables makes possible accurate measurement of nutrient input and output (erosion) and therefore establishes the relationship of the smaller ecosystem to the larger biospheric cycles. (iii) The small-watershed approach provides a method whereby such important parameters as nutrient release from minerals (weathering) and annual nutrient budgets may be calculated. (iv) It provides a means of studying the interrelationships between the biota and the hydrologic cycle, various nutrient cycles, and energy flow in a single system. (v) Finally, with the small-watershed system we can test the effect of various land-management practices or environmental pollutants on nutrient cycling in natural systems. 相似文献
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