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81.
82.
The oxygen isotopic composition of land-snail shells may provide insight into the source region and trajectory of precipitation. Last glacial maximum (LGM) gastropod shells were sampled from loess from Belgium to Serbia and modern land-snail shells both record δ18O values between 0‰ and − 5‰. There are significant differences in mean fossil shell δ18O between sites but not among genera at a single location. Therefore, we group δ18O values from different genera together to map the spatial distribution of δ18O in shell carbonate. Shell δ18O values reflect the spatial variation in the isotopic composition of precipitation and incorporate the snails' preferential sampling of precipitation during the warm season. Modern shell δ18O decreases in Europe along a N-S gradient from the North Sea inland toward the Alps. Modern observed data of isotopes in precipitation (GNIP) demonstrate a similar trend for low-altitude sites. LGM shell δ18O data show a different gradient with δ18O declining toward the ENE, implying a mid-Atlantic source due to increased sea ice and a possible southern displacement of the westerly jet stream. Balkan LGM samples show the influence of a Mediterranean source, with δ18O values decreasing northward.  相似文献   
83.
John Overton 《Geoforum》2010,41(5):752-762
Geographers have developed a keen interest in the social production of space - in the way meanings and values are ascribed to places as a result of changing social, cultural and political processes. There is a need to explore this approach further, seeing how social and economic values of places are inter-related and how these values are constructed in often deliberate and concerted ways. There is also a need to explore how such values are consumed: how the values in place are traded, appropriated and redistributed, both through the products of places and in land markets. This paper examines the New Zealand wine industry where certain wine regions have been identified and developed in ways which attempt to emphasise their distinctiveness in terms of wine quality and thus enhance the value of the wine produced. Different strategies have been employed in this process of place construction and this reflects the differential role of capital, striving on the one hand to increase the price and marketability of the products of distinctive places but, on the other, careful not to over-inflate land values and thus restrict further expansion. The paper suggests that the issue of consumption of space, involving a complex relationship amongst land, capital and place, is worthy of further exploration.  相似文献   
84.
张常桦  陈妮  赵亮  江悠丽 《地下水》2011,33(5):170-173
针对甘肃庆城县独特的土地利用过程中出现的一系列水生态环境问题,使用生态修复的概念,对其用地进行安排布局,并提出水生态环境建设用地空间管制、安全控制分区及水土流失区域坝系建设等修复措施。  相似文献   
85.
The questions of how land use change affects climate, and how climate change affects land use, require examination of societal and environmental systems across space at multiple scales, from the global climate to regional vegetative dynamics to local decision making by farmers and herders. It also requires an analysis of causal linkages and feedback loops between systems. These questions and the conceptual approach of the research design of the Climate-Land Interaction Project (CLIP) are rooted in the classical human-environment research tradition in Geography.This paper discusses a methodological framework to quantify the two-way interactions between land use and regional climate systems, using ongoing work by a team of multi-disciplinary scientists examining climate-land dynamics at multiple scales in East Africa. East Africa is a region that is undergoing rapid land use change, where changes in climate would have serious consequences for people’s livelihoods, and requiring new coping and land use strategies. The research involves exploration of linkages between two important foci of global change research, namely, land use/land cover (LULC) and climate change. These linkages are examined through modeling agricultural systems, land use driving forces and patterns, the physical properties of land cover, and the regional climate. Both qualitative and quantitative methods are being used to illustrate a diverse pluralism in scientific discovery.  相似文献   
86.
通过对临沂市部分县区土地开发整理项目规划设计变更实际情况的数据分析,对土地开发整理项目规划设计变更的类型进行了分类介绍,分析土地开发整理项目规划设计变更的主要原因是规划设计与项目区的实际情况脱节,并在此基础上提出了严格控制土地开发整理规划设计变更的对策。  相似文献   
87.
根据陆海相互作用的观点,黄河流域、黄河干流、河口三角洲及其邻近海区的生态环境相互联系,组成了一个有机的生态系统链,可称为黄河-渤海生态系统。黄河流域的降水量、土壤植被条件使黄河干流具有水少沙多、水沙异源和水资源缺乏的特征。干流入海水、沙通量变化影响了黄河三角洲地区的侵蚀、堆积和发育过程。黄河物质入海后在河口及邻近海域形成了具有高生产力的生态环境和著名的渔场。据此绘出了黄河-渤海生态环境内各环节相互联系的概念模式图,并提出了黄河流域大面积水土保持和南水北调工程逐步展开等新环境下,本区陆海相互作用的研究方向。  相似文献   
88.
Over the last decade, shifting strategies of capital accumulation have deepened the integration of land and associated primary commodities into circuits of investment. More than merely an economic revaluation of land, such integration involves an iterative rearrangement of the social and natural processes determining land’s material and symbolic qualities. Highlighting these shifts through a comparative study of investment processes for large-scale agricultural and extractive projects, we posit investment processes as assemblages proceeding in the context of different ontologies, valuations, and uses of land, which coalesce and compete with one other in complex ways, producing new spaces and subjectivities. Such assembling, we suggest, notably involves a discursive component involving the narration of the need for investment, an institutional component reforming regulatory arrangements, and an operational component enrolling labour, infrastructure, and ancillary resources associated with agricultural and extractive production. After examining each of these components in turn, we conclude with a discussion of tensions and contradictions inherent in ‘opening’ lands for investment and the business of harnessing agricultural and extractive resources.  相似文献   
89.
This paper explores territorial struggles around ecotourism in community-based conservation in wildlife rich Northern Tanzania. At the centre of analysis are two emblematic and distinctly different ecotourism business models that rely on a particular territorialization of property relations and resource control: one model is based on land sharing with local communities and villages, while the other relies on the appropriation of large parts of village land for exclusive access and control. Conceptually engaging critical geography debates on internal territorialization with a poststructuralist political ecology inspired by the framework of multiple environmentalities, the paper shows how ecotourism companies employ different techniques of government to secure business-friendly environments and territories in neoliberal conservation. Different business models underpin different processes of territorialization that in turn produce different modes of engagements and regimes of rule and authority. While the case of ecotourism through land sharing reinforces village land rights through a neoliberal environmentality, ecotourism through land appropriation illustrates how neoliberal, sovereign and truth environmentalities are put to work to facilitate the re-territorialization of property relations and resource control to undermine land rights of an entire village or an ethnic minority.  相似文献   
90.
以科尔沁沙地阿古拉苏木为典型代表区域, 应用1987-2006年20 a间12幅遥感影像及相应气候数据, 分析了地表环境变化与气候变化间的响应关系, 提出了表征响应敏感程度、影响程度大小排序的气候因子影响指数(CFII). 结果表明: 近20 a研究区地表环境变化表现为不断恶化的趋势. 各类地表环境变化与气候因子变化间有着良好的响应关系, 各类气候因子变化以不同方式和过程不同程度地影响着地表环境的变化. 响应敏感度最大, 即对地表环境变化影响最大的是相对湿度, 其次为降水量和蒸发量. 水分条件是制约干旱半干旱地区地表环境变化的主导因素.  相似文献   
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