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751.
Base cation concentrations in forest litter and topsoil have different responses to climate and tree species along elevational gradients 总被引:1,自引:0,他引:1
XUE Feng ZHAO Ming-fei WANG Yu-hang KANG Mu-yi XING Kai-xiong WANG Guo-yi SHI Jing-jing CHEN Chen JIANG Yuan 《山地科学学报》2019,(1):30-42
The forest litter is an essential reservoir of nutrients in forests, supplying a large part of absorbable base cations(BC) to topsoil, and facilitating plant growth within litter-soil system. To characterize elevational patterns of base cation concentrations in the forest litter and topsoil, and explore the effects of climate and tree species, we measured microclimate and collected the forest litter and topsoil(0-10 cm) samples across an elevational range of more than 2000 m(1243 ~ 3316 m a.s.l.),and analyzed the concentrations of BC in laboratory. Results showed that: 1) litter Ca concentration displayed a hump-shaped pattern along the elevational gradients, but litter K and Mg showed saddle-shaped patterns. Soil Ca concentration increased with elevation, while soil K and Mg had no significant changes. 2) Ca concentration in the forest litter under aspen(Populus davidiana) was significantly higher than that in all other species, but in topsoil, Ca concentration was higher under coniferous larch and fir(Larix chinensis and Abies fargesii). Litter K and Mg concentrations was higher under coniferous larch and fir, whereas there were nosignificant differences among tree species in the concentrations of K and Mg in topsoil. 3) Climatic factors including mean annual temperature(MAT), growing season precipitation(GSP) and non-growing season precipitation(NGSP) determined BC concentrations in the forest litter and topsoil. Soil C/N and C/P also influenced BC cycling between litter and soil. Observation along elevations within different tree species implies that above-ground tree species can redistribute below-ground cations, and this process is profoundly impacted by climate. Litter and soil Ca, K and Mg with different responses to environmental variables depend on their soluble capacity and mobile ability. 相似文献
752.
Kenneth R. Young 《Geographical review》2019,109(2):258-264
753.
Pier Luigi Sacco Maria Tartari Guido Ferilli Giorgio Tavano Blessi 《Urban geography》2019,40(4):529-554
In this paper, we critically examine the role of artistic locational choices and practices in the context of gentrification processes in urban renewal contexts. We characterize gentrification as a form of domestication of space, and explore the extent to which artistic choices and practices relate to such process with reference to the deontological dilemma of legitimization within the art system vs. responsible empowerment of vulnerable local constituencies. We illustrate our argument with an analysis of the High Line Art project, and show how this can be considered as a textbook example of art-driven space domestication leading to brutal forms of gentrification. We comment on the threat that this provides to the social credibility of artistic practices as an agency of responsible social change. 相似文献
754.
中国城市体系网络化研究 总被引:14,自引:1,他引:13
当前,学者普遍认同城市体系研究的重心从等级范式向网络范式转向。在大量的文献梳理基础上,阐述20世纪80年代以来中国城市体系研究范式的转向过程,并进一步梳理中国城市网络研究的进展、问题与关注重点。结果表明:2010年之后,网络成为中国城市体系研究的主流范式,等级体系文献数量呈波动递减趋势,全国和长三角成为热点关注区域;属性数据一定程度上弥补了早期城市网络研究中数据匮乏的状况,关系数据应成为未来研究的侧重点;不同研究视角及其所应用的数据存在着一定的局限性,多元视角的综合研究成为趋势。在此基础上,提出城市网络研究未来可能的突破点,包括:调整国家城市网络的研究框架、超越交通数据直接考察城市间的实体联系、测度企业外部的横向联系、有向加权网络分析和可视化、增加研究中的地理“意味”等。 相似文献
755.
社会-生态系统适应性治理研究进展与展望 总被引:7,自引:0,他引:7
社会—生态系统(SES)由社会子系统、生态子系统及两者的交互作用构成,具有不同于社会系统或生态系统单独具有的结构、功能和复杂特征。社会—生态系统适应性治理旨在通过适应性的社会权利分配与行为决策机制,使社会—生态系统能够在动态条件下可持续地保障人类福祉。适应性治理理论的形成受到“公共池塘资源管理”“韧性”和“治理”3方面理论的影响,并为“转型治理”与“协作治理”提供了建构基础。该理论具有以下3个主要目的:① 理解和应对社会—生态系统多稳态、非线性、不确定性、整体性以及复杂性;② 建立非对抗性的社会结构、权利分配制度以及行为决策体系,匹配社会子系统与自然子系统;③ 通过综合方法管理生态系统,使其可持续提供生态系统服务。因此,面对人类行为主导地表过程的“人类世”,实现适应性治理有助于应对社会—生态系统的复杂性与不确定性。鉴于中国的生态环境正处于迅速变化时期,且中国与世界各国间的相互影响日益复杂,未来研究可重点关注以下3个方面:① 理解耦合系统的多元互动过程,增强适应能力;② 强调社会—生态系统的整体性研究;③ 提高环境变化背景下理解和预测系统动态的能力。 相似文献
756.
This study examines whether an ecological worldview—operationalized by the New Ecological Paradigm (NEP) Scale--serves as the source of coherence of Environmental Concern (EC). Using data on four samples from the 1992 Gallup “Health of the Planet” Survey and the 2003 and 2010 Chinese General Social Surveys, we found that in all samples not only is the NEP the most powerful predictor of EC, but it also mediates the effects of socio-demographic variables on EC as hypothesized. The results confirm that the NEP is the source of coherence of EC, making it a meaningful construct. 相似文献
757.
Luca Collanega Katherine Siuda Christopher A.‐L. Jackson Rebecca E. Bell Alexander J. Coleman Antje Lenhart Craig Magee Anna Breda 《Basin Research》2019,31(4):659-687
Reactivation of pre‐existing intra‐basement structures can influence the evolution of rift basins, yet the detailed kinematic relationship between these structures and overlying rift‐related faults remains poorly understood. Understanding the kinematic as well as geometric relationship between intra‐basement structures and rift‐related fault networks is important, with the extension direction in many rifted provinces typically thought to lie normal to fault strike. We here investigate this problem using a borehole‐constrained, 3D seismic reflection dataset from the Taranaki Basin, offshore New Zealand. Excellent imaging of intra‐basement structures and a relatively weakly deformed, stratigraphically simple sedimentary cover allow us to: (a) identify a range of interaction styles between intra‐basement structures and overlying, Plio‐Pleistocene rift‐related normal faults; and (b) examine the cover fault kinematics associated with each interaction style. Some of the normal faults parallel and are physically connected to intra‐basement reflections, which are interpreted as mylonitic reverse faults formed during Mesozoic subduction and basement terrane accretion. These geometric relationships indicate pre‐existing intra‐basement structures locally controlled the position and attitude of Plio‐Pleistocene rift‐related normal faults. However, through detailed 3D kinematic analysis of selected normal faults, we show that: (a) normal faults only nucleated above intra‐basement structures that experienced late Miocene compressional reactivation, (b) despite playing an important role during subsequent rifting, intra‐basement structures have not been significantly extensionally reactivated, and (c) preferential nucleation and propagation of normal faults within late Miocene reverse faults and folds appears to be the key genetic relationship between contractionally reactivated intra‐basement structures and rift‐related normal faults. Our analysis shows that km‐scale, intra‐basement structures can control the nucleation and development of newly formed, rift‐related normal faults, most likely due to a local perturbation of the regional stress field. Because of this, simply inverting fault strike for causal extension direction may be incorrect, especially in provinces where pre‐existing, intra‐basement structures occur. We also show that a detailed kinematic analysis is key to deciphering the temporal as well as simply the spatial or geometric relationship between structures developed at multiple structural levels. 相似文献
758.
基于水资源约束的中国城镇化SD模型与模拟 总被引:1,自引:0,他引:1
中国城镇化正处于快速发展阶段,尽管经济和社会发展主控要素还在发挥重要作用,但水资源在生产、生活和生态方面发挥主控作用的局面愈益明显。在中国城镇化系统动力学(system dynamics,SD)模型基础上,从水资源供给、需求和水环境等层面将水资源作为主控要素嵌入原有模型中,拓展出基于水资源约束的中国城镇化SD模型,并对水资源利用进行了多情景模拟。结果表明:① 系统存流量和灵敏度检验证明模型模拟效果良好,具有可操作性。② 部门用水效率一定时,产业发展对水资源供需平衡的影响比人口增长更为明显。③ 在实行节水农业、节水工业、高生活需水、高生态环境需水和高再生水利用的综合协调方案中,2050年中国城镇化的发展约共需6789.70亿 m3水资源,基本实现水资源供需平衡。 相似文献
759.
Extensional fault and fold growth: Impact on accommodation evolution and sedimentary infill 总被引:2,自引:2,他引:0
Extensional faults and folds exert a fundamental control on the location, thickness and partitioning of sedimentary deposits on rift basins. The connection between the mode of extensional fault reactivation, resulting fault shape and extensional fold growth is well‐established. The impact of folding on accommodation evolution and growth package architecture, however, has received little attention; particularly the role‐played by fault‐perpendicular (transverse) folding. We study a multiphase rift basin with km‐scale fault displacements using a large high‐quality 3D seismic data set from the Fingerdjupet Subbasin in the southwestern Barents Sea. We link growth package architecture to timing and mode of fault reactivation. Dip linkage of deep and shallow fault segments resulted in ramp‐flat‐ramp fault geometry, above which fault‐parallel fault‐bend folds developed. The folds limited the accommodation near their causal faults, leading to deposition within a fault‐bend synclinal growth basin further into the hangingwall. Continued fold growth led to truncation of strata near the crest of the fault‐bend anticline before shortcut faulting bypassed the ramp‐flat‐ramp structure and ended folding. Accommodation along the fault‐parallel axis is controlled by the transverse folds, the location and size of which depends on the degree of linkage in the fault network and the accumulated displacement on causal faults. We construct transverse fold trajectories by tracing transverse fold hinges through space and time to highlight the positions of maximum and minimum accommodation and potential sediment entry points to hangingwall growth basins. The length and shape of the constructed trajectories relate to the displacement on their parent faults, duration of fault activity, timing of transverse basin infill, fault linkage and strain localization. We emphasize that the considerable wavelength, amplitudes and potential periclinal geometry of extensional folds make them viable targets for CO2 storage or hydrocarbon exploration in rift basins. 相似文献
760.
地球表层是人类生存的家园,地表形态直接或间接影响人类生活、生产和社会经济活动。地貌学和生态学是与人类关系密切的学科。自然实体与人文实体都依附于地表,研究生态与地貌关系的科学便统称为生态地貌学,直接影响人类生存选址、生存保障、生产方向、产业布局、交通、城乡建设等,因此,生态地貌学是保障人类生存与社会经济可持续协调发展的基础性与应用性极强的学科,是国家实现生态文明战略的基础性学科。生态地貌学研究生态与地貌两者相互作用形成的生态地貌综合实体,学科体系包含地貌基础学科、生态基础学科及其相互作用形成的生态地貌学科。生态地貌学科下又包含生态地貌区划学、生态地貌类型学、生态地貌资源学、生态地貌岩态学、生态地貌遥感与GIS技术、生态地貌管理与规划等分支学科,是目前仍然属于探索性的学科。生态地貌结构可表达为:由地貌与生物成分、类型、区域组合、数量构成及其空间排列组合方式。从生态地貌结构理论出发,对其功能进行系统梳理,主要可以归纳为区域结构、类型结构、资源结构、岩态结构等多种类型。不同结构类型具有不同的功能,主要功能有提升中国自然地理区划质量与空间定位功能、生态评估与生态设计功能、土地利用评估与利用结构调整功能、地质地貌灾害成因和防灾减灾对策功能等。故该研究意在实现生态地貌功能间协调、高效可持续,通过对各功能进行整合,形成功能体系,并从调控管理上提出了提升功能能力的设计路径。 相似文献