放牧,草原生态系统存在的基本方式——兼论放牧的转型

放牧是国内外普遍运用的土地管理的基本手段,至今全球陆地大约半数以上处于放牧管理之下。但受传统农耕文化的影响,我国当前对放牧管理系统存在很多误解,尤其是把草原的生态恶化、牧区贫困、文化落后都归罪于草原放牧,导致禁牧盛行。从放牧的基本内涵看,当前我国草原所面临的问题,不在放牧本身,而是对放牧认识的不足和放牧管理的缺陷,割裂了人居-草地-畜群之间的联系。从历史角度看,放牧做出了巨大贡献。而随着社会和科技的进步,放牧历经原始游牧期、放牧转型期与放牧现代化时期三阶段。西方发达国家在20世纪30年代就实现了放牧的现代化转型。畜牧业现代化的核心是以人居-草地-畜群放牧系统单元为内核的划区轮牧。划区轮牧是一种开放的农业技术体系,具有多种方式,适应于不同的农业系统,可兼顾生态与生产的需求,是草地放牧管理的重大进步。为了实现草原生态系统的生态和经济双重效应,我国畜牧业应该尽快实现草原管理和放牧的现代化转型。这是我国草地畜牧业现代化的必经之路,也是现代农业的必要内涵。     

我国亚热带山地生态系统脆弱区生态恢复的战略思想——基于长汀水土保持11年研究成果

在探析以长汀为代表的我国亚热带山地生态系统脆弱区生态恢复过程内在关联性的基础上,提出"天时、地利、人和"的生态恢复策略。该策略以人地关系和谐论为指导,其含义为:顺乎天时,最大限度地发挥自然界的再生能力;调控坡面径流,化地害为地利;发挥人的主观能动性,构建物质与经济良性循环的土地和谐利用模式。在实践这个策略过程中,必须实现在观念、策略、技术上的转变以及技术瓶颈、空间局限和体制障碍的突破。     

藏北草地生态系统可持续发展能力评价

藏北草地是我国重要的畜牧业生产基地和生态安全屏障。然而,草地退化引发了一系列的生态、经济、环境和社会问题,不仅直接威胁到我国的生态屏障安全和当地的畜牧业生产,而且严重影响着藏北草地生态系统的可持续发展。研究以藏北那曲地区为例,利用复合生态系统场方法,构建了以生态功能、生产功能和生活功能为基础的可持续发展评价指标体系和模型,并通过对1985-2008年那曲地区草地生态系统的发展变化分析,定量评价了草地生态系统的可持续发展能力。评价结果表明,藏北那曲草地生态系统的发展位已超过了系统的最大承载能力,发展势缺乏潜能,协调性较差,可持续发展度很低,草地生态系统处于不可持续的发展状态。     

生态系统固碳特征及其研究进展

生态系统固碳是人类应对气候变化以及全球系统变化过程的研究热点。论文结合生态系统固碳和碳汇概念,探讨生态系统自然固碳、人为工程固碳措施对生态系统功能的影响并分析生态系统固碳特征及风险。研究得出如下结论:陆地生态系统对CO₂的自然吸收与封存是相对安全有效的固碳措施,对人类与生态系统健康的影响要小于地质层与海洋层固碳。海洋生态系统固碳容易导致海水酸化以及生态系统不可逆的损害;由于地壳运动很难预测,所以地质层固碳可能面临不可预知的风险。因此,利用生态系统自然固碳能力、发展绿色固碳技术是降低人为工程固碳生态风险和减少CO₂排放到大气中的最佳选择。     

Materialphilia,biophilia, and sustainable use of the planet

SUMMARY

The intricate and complex relationships between transhumant pastoralists, livestock and environment at the high altitudes of Indian Central Himalaya has started to break down at an alarming rate. Some of the important factors attributed to this are depletion of grazing resources, commercialization of the rural economy, and integration of these communities with the mainstream of development through education and employment. Traditionally these livestock were assigned different roles in society depending upon their economic benefit and utility. The roles which once depended upon attitude to various risks, such as environmental, social and economic, have lost their significance due to changing of the production process. This paper gives an overview of the various types of roles the livestock played in the transhumant society, and how they are being replaced by the developmental process in the region, and whether the changes are sustainable for such remote regions in a developing country.     

Metal accumulation in sediment,water, and freshwater fish in a Dam Lake

Metal concentrations were determined in water, sediment, and freshwater fish samples (Squalus cephalus, Barbus esocinus, and Barbus xanthopterus) collected from Karakaya Dam Lake, Turkey, to estimate the risk of human consumption and pollution. Metal concentrations differed between the species (p??Zn?=?Cu in water and Fe?>?Zn?>?Mn?>?Ni?>?Cu in sediment. In general, the accumulation order of elements in the tissues all of the species sampled were found as Fe?>?Zn?>?Se?>?Mn?>?Cu?>?Ni?>?Cd in muscle, Zn?>?Fe?>?Mn?>?Se?>?Cu?>?Ni?>?Cd in gills, Fe?>?Zn?>?Se?>?Mn?>?Cu?>?Ni?>?Cd in liver and gonad, and Zn?>?Fe?>?Cu?>?Mn?>?Se?>?Ni?>?Cd in kidney. It was concluded that the fish from the dam lake are not heavily burdened with metals, but they should be controlled periodically to avoid excessive intake of trace metals by humans, and to monitoring the pollution of aquatic environment.     

Cd,Pb, and Cu in water and sediments and their bioaccumulation in freshwater fish of some lakes in Hanoi,Vietnam

The seasonal variations of Cd, Pb, and Cu in the water, sediments, and freshwater fish (Hypophthalmichthys molitrix, Cirrhinus molitorella, and Oreochromis mossambicus) of four lakes in Hanoi, Vietnam, were investigated. Samples for analysis were taken four times from April 2010 to March 2011. The levels in water were lower than the Vietnamese standards, except for Pb, but they were all much higher than the Canadian standards for protection of aquatic life; in the sediments, they were higher than world average levels. Bioaccumulation of the three metals in fish was site-dependent and species-dependent, but correlations of their levels in fish to those in water and sediments were weak. Levels of Pb in fish exceeded those of the UK and the WHO standards, and the recommended values of Vietnam for human consumption. Overall, the results show that the lakes are polluted with these metals, and consumption of high quantities of fish from them may be problematic. The outcome of this research helps to establish background data for future monitoring.     

Public attitudes and perceptions to the West-to-East Pipeline Project and ecosystem management in large project construction

Ecosystem management addresses transboundary, interdisciplinary and multiparty issues from an ecosystem perspective. In this regard, public participation of ecosystem management is particularly important for achieving a successful outcome. However, public attitudes and perceptions on ecosystem management in project construction are often ignored in the developing countries. Large project construction in China is booming, for example, oil/gasoline pipelines, water diversion projects, highway networks and high-speed railway networks. These projects may have important impacts on China's economy, as well as ecosystems. The perception of local people on these projects is crucial for their safe fulfilment. In this paper, the West-to-East Pipeline Project (WEPP), a large project in China built in 2004 to transport gas from the north-west to the south-east, was used as a case study to examine public participation and perceptions on ecosystem management. Field interviews were conducted in the summer of 2005 for data collection, and logistic regression models were used for data analysis. Modelling results show that public attitudes to WEPP construction are closely related to education, occupation and place of residence. Generally, interviewees with higher education and more involvement in WEPP have a positive attitude. However, local people have a poor understanding of ecological restoration and ecosystem management. For safe implementation of WEPP, some adjunct projects are required to improve the local economy and ecosystem functions, and different economic compensation schemes should be designed for stakeholders by region. Additionally, development strategies, such as offering part-time jobs, education and training to local farmers, are necessary to change attitudes and improve awareness on ecosystem management. It is also important to strengthen public participation in the early stages of project construction.     

Assessment of the erosion control function of forest ecosystems based on GIS: a case study in Zhangjiajie National Forest Park,China

Erosion control is one of the most important functions of forest ecosystems, and its accurate assessment is useful to illuminate the importance of forest ecosystem services for humans so as to rationally conserve forest resources. This paper examines Zhangjiajie National Forest Park, the first national forest park in China, to seek practical methods for assessment of the forest erosion control function using a geographical information system (GIS). The results show that the potential and actual amounts of soil erosion are 2.92 million ton and 0.14 million ton per year, respectively, in Zhangjiajie National Forest Park. The total reduction in soil loss reaches 2.77 million ton per year with the existence of a forest ecosystem. The erosion control function of near mature, mature and over mature broadleaf forest is excellent, and natural forest conservation and natural restoration of the degraded forest ecosystem can provide the largest benefits in soil erosion control. Nearly all the near mature, mature and over-mature forest in the park is at the top and in steep mountain areas, and could be rationally cut and utilized by local communities, but extensive timber felling should be strictly prohibited.     

海州湾生态系统健康诊断

根据开敞海湾浅海生态系统特征,构建了包含环境现状、环境风险、环境背景、系统结构功能和系统稳定性5类诊断指标以及24个诊断因子的浅海生态系统健康诊断指标体系,并采用层次分析法对海州湾浅海生态系统2009年12月和2010年11月的健康状况进行诊断.结果表明,2009年12月和2010年11月海州湾浅海生态系统的综合健康指数值分别为0.500～0.689和0.553～0.750,浅海生态系统处于亚健康～较健康状态,近岸海域基本处于亚健康状态,离岸海域基本处于较健康状态,近岸海域生态系统健康水平低于离岸海域,这与近岸海域开发活动干扰多以及环境压力大有关.