黄土丘陵沟壑区生态移民过程及其生态系统服务价值评价——以宁夏海原县为例

以海原县为研究对象,以2000、2005、2010和2015年遥感数据为基础数据,综合运用土地利用动态度、生态系统服务价值评价模型、地理探测器等模型对海原县2000—2015年的生态系统服务价值时空变化进行研究。结果显示：2000—2015年海原县土地利用类型发生明显变化,林地、建设用地、水域以及园地面积分别增加24 532.56hm2、13 233.71hm2、1 093.58hm2和812.16hm2,而耕地、草地和未利用地面积呈下降趋势,其中未利用面积下降幅度最大,共减少21 333.05hm2;研究期间海原县生态系统服务价值呈现出逐年增加的变化趋势,由2000年的37.25×108元增加至2015年的62.23×108元,变化率为67.07%,而林地、园地和水域面积的增加是海原县生态系统服务价值增加的关键;从态系统服务价值空间分布来看,海原县生态系统服务价值在空间呈现出由西南向东北递减的变化趋势;研究期间研究区生态系统单项服务价值均呈现出增加的变化趋势,其中废物处理和水源涵养增加量最大,其次是生物多样性和气候调节,而食物生产、原材料生产以及娱乐文化增加量最低,说明海原县的生态系统调节服务>支持服务>供给服务>文化服务;通过地理探测器诊断发现草地、园地、林地、气候调节、土壤形成与保护、生物多样性保护的决定力q值均＞0.8,说明这6项因子对研究区生态系统服务价值变化具有重要的影响作用。     

1975—2015年甘肃省白龙江流域自然保护区生态系统服务价值及其时空差异

利用1975-2015年7期遥感数据重建甘肃省白龙江流域8个野生动物自然保护区的生态系统时空变化特征,并在对该研究区各类生态系统服务价值当量修订的基础上,采用生态系统服务价值评估模型和敏感性指数,对不同时期的生态系统服务价值进行评估。结果表明:(1)白龙江流域自然保护区以森林生态系统为主,研究期内生态系统格局总体稳定,农田和裸地生态系统面积减少,而森林、草地、水域和人工表面生态系统呈增加趋势,且在2000年后变化最活跃。(2)研究区生态系统服务价值由1975年的239.68×10^8元上升到2015年的243.58×10^8元,净增加3.90×10^8元,农田和裸地生态系统服务价值持续减少,而森林、草地和水域生态系统服务价值则呈增加趋势。(3)整体上,研究区南部生态系统服务价值呈增长趋势,而中北部地区则处于阶段性变化状态,文县大鲵自然保护区单位面积生态系统服务价值密度最高,多儿自然保护区价值密度最低,且为唯一衰退型保护区。(4)在不同生态系统服务类型中,调节服务居主导地位,且以气候调节服务价值最高。白龙江流域自然保护区生态系统服务价值缺乏弹性,水域生态系统面积变化对研究区生态系统服务价值的变化具有放大作用。     

中国粮食生产时空演变规律与耕地可持续利用研究

随着全球粮食贸易格局的日益紧张,如何利用有限的耕地资源保证中国粮食安全成为新阶段的难题。本文从耕地可持续利用视角提出粮食稳产、增产策略,以期为粮食安全、耕地保护等国家战略提供理论支撑。基于1985—2015年中国31个省（自治区、直辖市）统计数据,以农业生态区为基本单元,采用比较分析法和GIS空间分析法,对中国粮食生产时空演变及其影响因素进行规律性探究。研究结果表明：（1）中国粮食产量呈“波动-上升”的趋势,但长江中下游区、江南和华南区粮食增长率较低,甚至出现减产现象。（2）中国粮食产量主产区逐渐由长江中下游区、江南和华南区向东北区、黄淮海区转移。（3）中国粮食生产的影响因素呈现阶段性和区域性规律。例如,东北区、西北区粮食生产主要受粮食单产、耕地面积等影响;黄淮海区、内蒙古高原和黄土高原区、云贵高原和横断山区主要受粮食单产影响。（4）中国各区耕地存在不同类型和不同程度的耕地非持续问题,在西北区、内蒙古高原和黄土高原等生态脆弱区域较严重。     

Is There Any Correlation Between Landscape Characteristics and Total Nitrogen in Wetlands Receiving Agricultural Drainages?

In the case of increasing fragmentation of wetlands, the study of the relationship between wetland landscape characteristics and total nitrogen(TN) in water is of great significance to reveal the mechanism of wetland water purification. Taking the Naoli River(NR) wetlands in Northeast China as the research object, 10 uniformly distributed sampling sites in the study area were sampled in August 2015 to test the TN concentration and interpret the images of NR wetlands in the same period. Taking the sampling site as the control point, the whole wetlands were divided into 10 regions, and the landscape index of each region was extracted. In order to reveal whether the landscape characteristics are related to the TN concentration in the wetlands water body, the landscape index and the TN concentration in the control point water body were analyzed by correlation analysis, step-by-step elimination analysis and path analysis to reveal whether the landscape characteristics are related to the TN concentration under wetlands receiving agricultural drainages. The results showed that the correlation coefficients between four area indexes or eight shape indexes and TN concentration did not reach a significant correlation level(P > 0.05), indicating that TN removal was not only determined by a single landscape index. The path coefficient of edge density(ED) index is –0.41, indicating that wetland patch connectivity is the primary factor of TN removal, and there is no relationship between the larger patch area and the higher TN removal. The removal of TN in wetlands is restricted by the synergistic effect of landscape area and shape characteristics.     

A National Key R&D Program: Technologies and Guidelines for Monitoring Ecological Quality of Terrestrial Ecosystems in China

Ecological quality is defined as the stability, adaptability and resilience of an ecosystem. Monitoring and assessing ecological quality are important bases for China's ecological civilization construction. The national key research and development program “Technologies and guidelines for monitoring ecological quality of terrestrial ecosystems in China”, launched in July 2017, includes plans to study the observation technologies and provide guidelines on the ecological in-situ observation, the regional biodiversity and ecosystem function monitoring and its applications, all of which contribute to national ecological quality assessment. A year after its implementation, some important progress has been achieved, such as building the indicator system for comprehensive monitoring of ecological quality and improvement of the methods, mass data transmission, infrared camera-based monitoring of biodiversity, multi-angle automatic spectral observation systems, and unmanned aerial vehicle (UAV) based desert monitoring. We have organized this special issue and attempted to introduce the monitoring techniques and assessment methods on ecological quality from different perspectives in order to further promote the development of ecology and its observation methods.     

Evaluating practical macrophyte control tools on small agricultural waterways in Canterbury,New Zealand

Excessive macrophytes can cause significant problems in agricultural waterways requiring active management. Conventional control techniques can have a range of adverse effects. We investigated several control tools in two experiments: firstly, we tested eight treatments at a small-scale (2?m?×?2?m). We found intensive hand weeding, weed mat and herbicide spraying to be effective treatments, reducing macrophyte cover to <5%. Hand weeding and weed mat immediately reduced cover, while dieback from herbicide took two months. Weed mat was a novel and effective control mechanism along stream banks. Secondly, we tested the impact of shading on macrophyte growth. Macrophyte growth was enhanced under partially shaded conditions, but with 80% effective shading over the entire channel, cover was reduced to 17%. Once treatments ceased, macrophytes grew back within 3–5 months. Long-term, control methods will require combinations of tools but will need to include optimal shading for the target species.     

The Geography of Education and the Education of Geography: Agricultural Extension and the Political Ecology of Education

The spatial nature of learning is increasingly a focus of geographic inquiry. I argue that the spatiality of education, which is where formal learning occurs, has the potential to shape students’ spatial imaginaries. I analyze the role the spatiality of agronomic education plays in the historical construction of the social and physical landscape in southeastern Pará, Brazil. In opposing ways, the first Green Revolution, and agrarian social movements’ more recent agroecological Green Revolution are found to structure agronomic education and spatial imaginaries. The perspectives of agricultural extension agents trained in traditional agronomic programs are compared with teachers from an agroecological school located in an Amazonian agrarian reform settlement of Brazil's Landless Workers’ Movement. I collected these data over 17 months of ethnographic fieldwork. To analyze these data, I employ a political ecology of education perspective, which highlights how education and political economy interact to mediate relations with, access to, and contestations over natural resources. The geography of education and the education of geography exist in a complicated feedback cycle: Education is not neutral but ideologically charged and affects conceptions of productive landscapes, providing students intellectual and economic power to put their visions of landscape into effect.     

基于Meta回归方法的中国内陆河流域生态系统服务价值再评估

将流域生态系统服务的经济价值纳入成本效益分析,是解决生态环境问题和实现流域生态资源可持续配置的关键。近年来随着价值评估文献量增加,评估的价值及其影响因素等研究结论由于存在诸多争议而难以应用于管理实践。首次应用Meta回归分析对中国内陆河流域生态系统服务的价值进行综合再评估,结果发现:在价值评估研究中研究对象、受访者、测度方法、撰写发表等4个环节的特征对评估价值均具有显著影响,其中,石羊河和塔里木河的评估价值显著高于黑河,上游的评估价值显著高于中游和下游,二分式条件价值评估法所评估的价值与选择实验法没有显著差异,但显著高于其他条件价值评估法;此外,时间对评估价值呈现显著"衰减效应",每年下降2%～3%,且期刊文献的评估价值显著高于其他文献的评估价值;通过运用n-1数据分割技术,本文将Meta回归方程结果运用到样本外效益转移并对其进行评估,得到的中位数转移误差为27.12%。相较于现有研究,该结果处于可接受范围。因此,本文运用的Meta回归分析适用于中国内陆河流域效益转移政策地的生态系统服务价值评估。     

环渤海地区农业地域功能演进及其影响因素

农业地域功能是农业地理学的重点理论问题之一,也是关乎粮食安全和区域农业可持续发展的重要实践课题。以环渤海地区为例,通过构建评价体系开展农业地域功能划分及其演进分析,利用空间计量模型诊断农业地域多功能形成的影响因素。结果表明：① 环渤海地区生态保育功能的空间集中度较高,农产品供给、就业与社会保障、文化传承与休闲功能则较低,4种功能空间格局具有显著规律性。② 农产品供给功能显著增强,主要分布区域向平原农区聚集;就业与社会保障高值区从内陆向沿海转移;山地丘陵生态保育功能有所增强;市辖区及周边的文化传承和休闲功能较显著。③ 农产品供给功能主导型县域集中于冀中南平原、鲁西北冲击平原、胶莱平原和辽河平原西部;社会保障主导型集中在燕山山麓平原、滨海平原、胶东半岛以及黄河三角洲;生态保育主导型集中在冀北坝上高原、燕山山地地区,以及辽西、辽东山地丘陵区和京津冀都市圈周边;文化传承与休闲功能集中于京津冀、辽中南和济南都市圈及周边;综合型位于鲁西南黄淮平原与鲁中南丘陵地区。④ 自然因素对农产品供给、就业与社会保障和生态保育功能的形成均具有显著影响;社会经济因素对4种功能的作用则具有较大差异。     

中国省域生态系统服务足迹流动及其影响因素

区域间由供给与消费不均衡所引起的生态系统服务流动,逐渐成为新的研究热点。选取具有代表性的食物供给服务、淡水供给服务和固碳服务,运用生态系统服务足迹算法和多区域间投入产出模型,核算中国省区典型生态系统服务足迹和省域间的动态流动以及影响因素。研究表明：中国省域人均食物供给服务足迹为1.16 hm²/人,人均淡水供给服务足迹为0.06 hm²/人,人均固碳服务足迹为2.92 hm²/人,但由于人口数量、地区发展和单位能耗等因素的影响而具有明显的区域差异性,因此供给与需求的不均衡导致了服务足迹在空间上的流动。同时,生态系统服务足迹与各影响因子呈正相关,表明生态环境与经济增长的可持续发展转好的拐点还未出现。