Research into urban expansion patterns and their driving forces is of great significance. Under the background of the integrated development of the Beijing-Tianjin-Hebei (Jing-Jin-Ji) urban agglomeration, it is important to study the temporal and spatial patterns of urban land expansion and the driving forces development. This paper uses land-use data of the Jing-Jin-Ji urban agglomeration from 1990 to 2015 and reveals the multi-dimensional characteristics of the urban land expansion patterns. We then combine the urban spatial interaction and the spatial and temporal nonstationarity of the urban land expansion process and build the center of gravity-geographically and temporally weighted regression (GTWR) model by coupling the center of gravity model with the GTWR model. Using the center of gravity-GTWR model, we analyze the driving forces of urban land expansion at the city scale, and summarize the dominant mode and core driving forces of the Jing-Jin-Ji urban agglomeration. The results show that: (1) Between 1990 and 2015, the expansion intensity of the Jing-Jin-Ji urban agglomeration showed a down-up-down trend, and the peak period of expansion was in 2005-2010. Before 2005, high-speed development was seen in Beijing, Tianjin, Baoding, and Langfang, which were then followed by rapid development in Xingtai and Handan. (2) Although the center of gravity of cities in the Jing-Jin-Ji urban agglomeration showed a divergent trend, the local interaction between cities was enhanced, and the driving forces of urban land expansion showed a characteristic of spatial spillover. (3) The spatial development mode of the Jing-Jin-Ji urban agglomeration changed from a dual-core development mode to a multi-core development mode, which was made up of three function cores: the transportation core in the northern part, the economic development core in the central part, and the investment core in the southern part. The integrated development between functional cores led to the multi-core development mode. (4) The center of gravity-GTWR model analyzes urban land expansion as a space-time dynamic system. The model proved to be feasible in the analysis of the driving forces of urban land expansion.

城镇用地扩展格局及驱动力研究对城市群发展规划与决策具有重要意义。以京津冀地区为例,基于城镇用地扩展强度指数、城镇用地扩展差异指数、分形维数、土地城镇化率和重心转移模型,多维解析了城市群城镇用地扩展格局特征,并耦合重心转移模型和时空地理加权回归（GTWR）模型构建重心-GTWR模型,在对空间格局进行长时间序列多维度指标分析的基础上,运用该模型依序对其特征进行驱动力解读,进而总结凝练京津冀区域发展的主导模式与城市核心驱动力。主要结论为：① 1990-2015年,京津冀城市群城镇用地扩展强度呈现“下降—上升—下降”的趋势,高峰时期在2005-2010年,在2005年之前高速发展城市集中在北京、天津、保定和廊坊,2005年之后集中在邢台和邯郸;② 城市群城镇用地重心虽呈现出发散态势,但城市之间的局部相互作用力逐渐增强,城镇用地扩展驱动力表现出空间溢出特征;③ 京津冀城市群空间发展模式由以北京和天津为中心的双核发展模式向多核发展模式转变,并出现北部资源运输核心、中部经济发展核心和南部投资发展核心三大功能核心组团,城市群趋向于多核功能协同发展模式;④ 重心-GTWR模型结合了时空非平稳性和城市空间相互作用,将城市群城镇用地扩展作为一个时空变化系统进行分析,经验证,该模型在城镇用地扩展格局驱动力分析研究中具有可行性。

Mega- urban agglomerations in China play a vital role in both national economic development strategies and national new-type urbanization, and undertake important historical responsibility with the world economic center transfer to China. However, they suffer a series of increasingly serious eco- environmental problems in the process of development. Thus,studies on the interactive coupled effects between urbanization and eco-environment in megaurban agglomerations are the frontier areas and high priority tasks in the earth system science for the future ten years. This paper analyses the basic theory frame of the interactive coupled effects between urbanization and eco- environment in mega- urban agglomerations systematically. In theoretical aspect, based on the nonlinear relationship and coupling characteristics of the natural and human elements in mega- urban agglomerations system, we could estimate the interactive coercing intensity, nearcoupling and telecoupling mechanism ofthe inside and outside mega-urban agglomerations system after scientific identification of the key elements, and then form the basic interactive coupling theory. Moreover, we could build a spatio- temporal coupling dynamic model, which is integrated with multi- elements, multiscales,multi-scenarios, multi-modules and multi-agents. The model will be used to develop the intelligent decision support system for urban agglomeration sustainable development. In methodology aspect, the mega- urban agglomeration is regarded as an open complex giantsystem. We should establish the standardized shared database for exploring the interactive coupled effects between urbanization and eco- environment. Then using new technology for analyzing big data and the integration methods incorporating of multi- elements, multi- scales,multi- targets, multi- agents, multi- scenarios and multi- modules, we can build a methodology framework to analyze the complex interaction coupling between urbanization and ecoenvironment. The technical route is to analyze spatiotemporal evolution characteristics, identifythe key elements, interpret coupling relationship, reveal the mechanism of coercing effect, find the general rules, filtrate the control variables, solve the critical thresholds, conduct regulation experiments, simulate different scenarios, propose an optimized schemes, and achieve national goals. Furthermore, we could put forward the overall optimization scheme. In general, this research could provide theoretical guidance and method support for the transformation and sustainable development in mega-urban agglomerations.

特大城市群地区是国家经济发展的战略核心区和国家新型城镇化的主体区,担当着世界经济重心转移承载地的历史重任,但在发展过程中面临着日益严重的资源与生态环境的胁迫压力。开展特大城市群地区城镇化与生态环境交互耦合效应的研究,是未来10 年地球系统科学研究的前沿领域和高优先研究主题。本文系统解析了特大城市群地区城镇化与生态环境交互耦合效应的基本理论框架。首先从理论上分析了特大城市群系统各自然要素和人文要素交互作用的非线性耦合关系及耦合特征,科学辨识近远程主控要素作用下城市群系统内外部各要素相互作用的胁迫强度、近远程耦合机理与规律,总结特大城市群地区城镇化与生态环境交互耦合圈理论,进一步构建多要素—多尺度—多情景—多模块—多智能体集成的时空耦合动力学模型,研发特大城市群地区可持续发展优化智能调控决策支持系统；其次从方法上将特大城市群地区视为一个开放的复杂巨系统,在建立同一标准化共享数据库的基础上,采用多要素—多目标—多模型—多情景环境下的城镇化与生态环境交互耦合集成技术方法、大数据支持下的城镇化与生态环境交互耦合技术方法,构建多尺度—多技术—多智能体集成的城镇化与生态环境交互耦合技术框架,按照分析时空演变特征—寻求主控要素—辨识耦合关系—揭示胁迫机制—发现耦合规律—筛选调控变量—求解临界阈值—进行调控试验—完成情景模拟—提出优化方案—完成情景模拟—提出优化方案—实现国家目标这样一条技术路径,提出解决问题的整体优化方案。本文旨在为特大城市群地区由问题集中区转为可持续发展区提供理论指导和方法支撑。

Understanding varying levels of biodiversity within cities is pivotal to protect it in the face of global urbanisation. In the early stages of urban ecology studies on intra-urban biodiversity focused on the urban-rural gradient, representing a broad generalisation of features of the urban landscape. Increasingly, studies classify the urban landscape in more detail, quantifying separately the effects of individual urban features on biodiversity levels. However, while separate factors influencing biodiversity variation among cities worldwide have recently been analysed, a global analysis on the factors influencing biodiversity levels within cities is still lacking. We here present the first meta-analysis on intra-urban biodiversity variation across a large variety of taxonomic groups of 75 cities worldwide. Our results show that patch area and corridors have the strongest positive effects on biodiversity, complemented by vegetation structure. Local, biotic and management habitat variables were significantly more important than landscape, abiotic or design variables. Large sites greater than 50 ha are necessary to prevent a rapid loss of area-sensitive species. This indicates that, despite positive impacts of biodiversity-friendly management, increasing the area of habitat patches and creating a network of corridors is the most important strategy to maintain high levels of urban biodiversity. © 2015 John Wiley & Sons Ltd/CNRS.

Urban spatial expansion has been research hotspot of urban geography for a long time. However, urban spatial progress and its driving forces showed diversified state under the context of different political systems and different development phases in the world. For example, there are debates on metropolitan expansion path between Western countries and China. One view advocated that metropolitan spatial expansion showed a trend from clustered to dispersed under the role of scale-economy. Another view found that above theory could not explain metropolitan spatial expansion progress in developing countries, such as China and India. In these metropolitan regions, rapid urban spatial expansion existed in "urban-rural integration" areas, not central big cities of metropolitan regions. Thus, it was different from Western developed countries due to particular political and economic factors in developing countries. In order to clarify metropolitan spatial pattern in a transitional period from planned economy to market economy, we utilized nighttime light data to analyze Beijing-Tianjin-Hebei metropolitan area from 1992 to 2012 as a case. A series of measurement methods has been used in the study, such as expansion intensity index, spatial correlation model and multi-dimensional model. The results are as follows: (1) Beijing, Tianjin, Tangshan were hotspot regions of metropolitan expansion during the whole research period. "Triangle region" among Baoding-Tianjin-Hebei were coldspot regions of metropolitan expansion. (2) Although metropolitan expansion has showed a dispersed trend, centralized powers are still strong in the progress of metropolitan development. (3) Metropolitan driving forces showed a diversified state. Market power was the main driving forces, followed by administration power, exogenous power and endogenous power. Market power, administration power and exogenous power has showed an upward trend. However, endogenous power has showed a downward trend. (4) We put forward some policy suggestions to optimize metropolitan spatial structure, such as reducing administrative intervention, building market-driven mechanism, strengthening internal and external two-way reform and promoting industrial upgrade.

针对中西方城市群空间扩展路径研究的争论,以京津冀城市群为例,运用夜间灯光数据,采取扩展强度指数、空间关联模型、多维驱动力分析模型,定量揭示了城市群时空扩展路径及其动力机制。结果表明：① 1992-2012年,京津冀城市群时空扩展呈现以京津唐为核心的中心集聚扩展模式,保定—衡水—石家庄之间的“三角地带”成为城市群空间扩展的冷点区;② 城市群空间扩展虽然已经出现了扩散势头,但向心集聚的惯性作用力依然强大;③ 城市群时空扩展的动力机制表现出以市场力为主要驱动因子的特征,行政力、外向力和内源力对城市群空间扩展的影响作用依次递减,从城市群空间扩展的驱动力演化趋势看,市场力、行政力、外向力的影响呈现上升趋势,而内源力的影响系数则呈现下降趋势。最后,提出降低行政干预、构建市场主导机制、强化内外双向开放、推动产业升级政策建议,促进城市群空间结构持续优化。

Spatial pattern of population distribution has a typical character of scale dependency. Fine-scale estimation of the population distribution has been a huge challenge in the field of population geography. In China, township is the finest administrative unit in official population census data. Thus, population density data at township level can be used to describe and characterize the population spatial pattern and changes elaborately, and support optimized layout plan of Chinese population, and government policy decision making. Township boundaries across 25 provinces in China had been collected in this study. The 5th national population census data was spatially joined to the boundary layer for population density calculation. Methods of Lorenz curve, geo-spatial analysis, and latitude/longitude transect had been applied to reveal the agglomeration degree, spatial patterns of population distribution with latitude and longitude. Based on the correlation and stepwise regression analysis, four variables, including relief degree of land surface (RDLS), water system density (WSD), road system density (RSD) and nighttime light index (NTL), were introduced to check the variety of population distribution in each province. The results showed that: (1) the variety of population distribution can be distinguished clearly by the mean population density on township scale than that of county level. (2) The overall population distribution can be characterized as dense in the southeast and sparse in the northwest, while lower population density occurs in some part of southeastern China, and vice versa. (3) The population density at township level along six designed longitude and latitude transects varies greatly. The possible impact factors include the three-level landscape features, local topography, regional economy, and the proximity to coastline, transportation hub, and hydrological systems. The correlation coefficient at provincial level, between the RDLS, WSD, RSD, NTL, and the population density has been identified as 0.56, 0.28, 0.61, and 0.69, respectively. At township level, topography and economy exert more impacts on population distribution in Liaoning, Jilin, Beijing, Tianjin, Shanghai, Hebei, Henan, Shaanxi, Shanxi, Shandong, Anhui, Jiangsu, Hunan, Hubei, Jiangxi, Zhejiang, Fujian, Guangdong, and Hainan. In addition to the four factors mentioned above, it is necessary to introduce more natural or social factors to explore the population distribution pattern in Tibet, Qinghai, Inner Mongolia, Yunnan, and Guizhou. This study expanded the research scale and dimension of the research in population geography research in China. The resulted population density dataset in 2000 is expected to enrich the baseline data resources for population geography development in China and the world.

人口空间分布具有典型的尺度特征,精细尺度的人口分布是当前人口地理学研究的热点和难点。乡镇（街道）是中国人口普查数据公开发布的最小行政单元,乡镇级人口密度计算及其分布特征研究能够更客观、精细地刻画中国人口分布的空间格局和态势,为促进中国人口的合理优化布局提供科学依据和决策支持。本文收集处理了2000年中国25个省（直辖市、自治区）的乡镇（街道）级行政边界数据,基于第五次人口普查乡镇（街道）人口统计数据,计算了乡镇级平均人口密度。采用Lorenz曲线、空间分析及样带分析的方法,分析了研究区乡镇（街道）人口分布的疏密结构、空间集聚性、纬向和经向规律。利用相关分析和逐步回归分析,分省探究了地形起伏度、水网密度、路网密度及社会经济发展水平（利用夜间灯光指数表征）等4个因素对于乡镇级人口分布的影响。研究表明：① 乡镇级平均人口密度能够有效区分出县域内部的人口密度高低差异,整体不均衡性高于基于县级平均人口密度的研究结果;② 乡镇（街道）人口分布总体规律是西北稀疏东南密集,同时,东南密中有疏,西北疏中有密;③ 乡镇（街道）人口分布的经纬向规律变异较大,既受中国三级阶梯地貌大势的影响,也受局部微地形及区域中心城市的影响,并和海岸线、交通枢纽及大江大河的分布具有一定的空间耦合性。④ 乡镇级平均人口密度与地形起伏度、水网密度、路网密度及夜间灯光指数等显著相关,省级平均相关系数分别为-0.56、0.28、0.61、0.69。⑤ 在乡镇尺度上,地形条件及区域发展水平对辽、吉、京、津、沪、冀、豫、陕、晋、鲁、皖、苏、湘、鄂、赣、浙、闽、粤、琼等省份的人口分布具有较强的决定作用。⑥ 对于藏、青、蒙、滇、黔等5省或自治区,需要引入更多的自然环境及社会因素来解释其人口分布的特殊规律。本研究扩充了中国人口地理学的研究尺度和维度,并引入了新的定量分析和空间分析方法,所构建的覆盖中国25省（直辖市、自治区）的乡镇（街道）级人口分布科学数据集丰富了中国人口地理学的2000年本底数据资源。

Understanding the evolving spatial pattern of land use is the basis of the theory and practice of land use/cover change (LUCC). It is helpful to optimize the use of land resources spatially and to improve the level of land use planning and management when the spatial patterns of land use are described effectively. At present, the commonalities in the scope of the spatial pattern of land use are still unclear, and research on the spatial pattern of land use has only recently begun to pay attention to the shape, patch distribution, structure, and relationships among different types of land use. In addition, the correlations among different pattern indicators have resulted in the redundancy in the pattern metrics. Further study is needed to establish the corresponding relationships between indicators and land use spatial patterns. This study summarized the area, shape, and patch distribution for land use maps as geometric characteristics, and summarized the structure and diversity as land use class characteristics. Based on the above conceptual model, an index system of land use spatial patterns was established. Then, the corresponding relationships between the indicators and the spatial patterns were established using fuzzy C-means clustering. The results indicated that the geometric characteristics of land use in China could be divided into five types: a simple large patch type, a complex large patch type, a complex small patch type, a simple small patch type, and a scattered type. Different geometric features reflected the characteristics of the area, the shape and the patch distribution and the combination of regional land use types. In 2010, there were 61 structures of land use in China, but a subset of 14 structures was the majority. The structural characteristics clustered in space and showed apparent spatial heterogeneity of different land use types. The diversity of land use in China was dominated by 3-5 categories, accounting for 66.69% of all the grids. The diversity over space was generally high in the northeast and the southeast, but low in the northwest. In summary, this study enriches the theoretical system of land use spatial pattern and fills a gap in the systematic description of the overall spatial patterns of China's land use.

土地利用空间格局研究是土地利用/覆盖变化（LUCC）理论和实践的基础,对土地利用空间格局进行有效刻画有利于国土资源空间优化,提升土地利用规划和管理水平。由于土地利用空间格局的研究范畴尚不明晰,目前土地利用空间格局的研究对形状、斑块分布和结构等方面关注较少,缺乏对不同土地利用类型间相互关系的研究;同时,格局指标繁多且存在较大的相关性,如何建立指标与土地利用空间格局的对应关系值得进一步研究。本文在深刻理解土地利用空间格局内涵的基础上,将面积、形状和斑块分布总结为土地利用几何特征,将结构和多样性总结为土地利用类型特征,建立了土地利用空间格局刻画指标体系,利用模糊C均值聚类分析,明确了指标与空间格局间的对应关系。结果表明,中国土地利用几何特征可以划分为简单大斑块型、复杂大斑块型、复杂小斑块型、简单小斑块型和散布型五种,不同的几何特征反映了不同土地利用类型的面积、形状和斑块分布的特点,体现了区域土地利用类型的组合关系。2010年中国土地利用共存在61种不同的结构,但主要的结构类型仅有14种,结构特征具有明显的空间聚集性,体现了不同土地利用类型的空间分异性。中国土地利用多样性以3~5类为主,占比达66.69%,其特征总体上呈现“东北、东南高,西北低”的态势。该研究丰富了土地利用空间格局研究的理论体系,填补了中国土地利用整体空间格局刻画的空白。

Since the reform and opening up, the PRD (Pearl River Delta) region has started a rapid urbanization process by making full use of its open-policies and location advantages. However, it was this rapid development model that brought the PRD region into trouble when the international financial crisis broke out in 2008. In response to the crisis, the PRD region began to explore a new way to promote the process of urbanization. Firstly, this paper reviews the features of traditional urbanization in the PRD, which are foreign capital promoting, production factors driving, developing from below and open-policies oriented. Accordingly, this paper believes the reasons that make the PRD region into dilemmas are the rising of labor costs, the shortage of land resources, the restriction in exports and the constraints of environment. Then the paper puts forward the main four characteristics of the new urbanization process in the PRD region: (1) Seeking new impetuses for development by substituting the "resource oriented" mode with the "knowledge source oriented" mode. (2) Transforming to a composited development model which can activate the domestic capital, the heavy industry, and the large-scale enterprises instead of the traditional one relying on foreign capital, light industry and small business. (3) Changing the economic-centered strategy to the human-oriented concept. (4) Improving development quality through strengthening infrastructure construction, optimizing urban image and highlighting culture. (5) Promoting urban-rural coordination by implementing the rural revitalization strategy. Finally, the paper explores and comes to conclusions on four key issues about the new process of urbanization in the PRD region: (1) The essence of the new urbanization process in the PRD is to rely on technological progress to promote the transformation and upgrading of the industry. (2) The PRD region has some advantages in production efficiency, foreign trade, innovation, market economy consciousness and economic internationalization. If it can successfully get rid of the path dependency relying on the technological innovation, the "Pearl River Delta model" will become a typical one of urban agglomeration development in China. (3) The PRD region has to strengthen the innovation and reform, accelerate the transformation of social development and coordinate the relationship between urban construction and the carrying capacity of resources and environment, so as to break through the Middle Income Trap. (4) The PRD region should make good use of the national strategy on building the Guangdong-Hong Kong-Macao Greater Bay Area to deepen its cooperation with Hong Kong and Macao and play a greater role in global competition.

改革开放以来,珠三角地区依靠优惠政策,利用区位优势,吸收外来投资,开始了快速城镇化的进程。总结珠三角快速城镇化的主要特点,即在开放政策的导向下,以土地、劳动力等生产要素为基础,外资推动、自下而上的城镇化。然而,2008年国际金融危机以来,这种模式的问题充分暴露。分析传统城镇化模式所遇的到劳动力成本上升、土地资源短缺、产品出口受限等困境,提出珠三角地区在解决困境中所形成的城镇化新进程的基本特点,即创新引领、复合驱动、以人为核心、强调品质、城乡协调发展并对珠三角城镇化新进程的本质特点、能否成功转型、与粤港澳大湾区的关系,以及能否再次成为中国城镇化的典范进行了探讨,以期为新时期珠三角地区以及中国城镇化可持续发展提供参考。