描绘了1996-2006年间中国城乡建设用地增长及其占用耕地的时空特征,探讨了城乡建设占用耕地的驱动机制。研究发现：人口流动为主的城镇化模式导致农业转移人口在城乡“两头占地”,这是中国城乡建设用地持续扩张的主要根源;各类开发区的设立和扩张都以占用耕地为主,对城乡建设占用耕地的贡献超过一半;而城市和镇的扩张速度更慢、土地来源更为多元。实证结果表明,投资和产出增长的差异性对城乡建设及其耕地占用的时空格局起到了关键作用;中西部地区的基础设施建设占用了大量耕地,但对区域经济发展和人口集聚的带动作用有限;以开发区为载体的产业集聚发展模式有利于中西部地区的土地集约利用和耕地保护,而东部沿海地区的省级开发区则容易成为地方政府的圈地运动。土地集约利用和耕地保护政策应重点解决农业转移人口城乡同时占地的问题,发挥城镇化的节地效应,并强化政策的区域差异性和针对性。

黄河流域湿地为我国生物多样性维持提供了重要生境.本研究基于黄河流域气候分区、地貌单元及湿地遥感数据,构建黄河流域生态地理综合湿地分类系统.在系统保护规划理论框架下,将湿地气候-地貌分类单元作为生态系统层次保护对象,结合黄河流域鸟类分布范围作为物种层次的保护对象,设定30%湿地优化目标,将公路、铁路、城镇、农村居民点、水坝等作为度量因子创建黄河流域保护代价图层,并利用系统保护规划工具——Marxan软件构建黄河流域湿地保护优化格局,识别湿地保护空缺.结果表明: 黄河流域大部分沼泽湿地集中在黄河上游区域,目前源区保护区覆盖面积大,在内蒙古、甘肃及四川部分区域一些稀有湿地类型游离在保护体系外;黄河中游湿地类型以河道和河滩湿地类型为主,保护覆盖率极低,保护空缺严重,经优化保护网络体系后,保护成效可分别得到29.1%、37.6%的提升.黄河下游湿地主要集中在黄河三角洲区域,目前保护体系完整,保护空缺面积极小.总体上,黄河流域中游河流湿地的保护空缺比例最高,亟需重视.本研究基于湿地保护格局优化结果分区分析黄河流域湿地保护模式,为黄河流域湿地的保护规划管理提供了科学性建议,从宏观层面上为黄河流域水生态保护奠定了基石.

Yellow River basin is a significant habitat for biodiversity conservation in China. Here, we established a integrated classification system of wetlands based on climate types and geomorphological units, with which as the coarse-filter surrogates of biodiversity elements to complement the fine-filter surrogates of distribution of focal bird species. Then, we applied the theoretical framework of systematic conservation planning (SCP), with those two biodiversity surrogates as protection objects and watershed as planning units. We calculated social and economic costs (including roads, railroads, towns, rural settlements, dams) and set targets of 30% to input Marxan to figure out the optimal set of planning units, which met the protection target with the minimum of social economy cost and land resources. We identified a conservation priority pattern by calculating the irreplaceability of each unit by Marxan. Then, we compared the priority pattern with the existing reserve system to analyze conservation gap in the Yellow River basin. The results showed that most marsh wetlands were concentrated in the upper reaches of the Yellow River. The coverage of reserves in the source area was large. Some rare wetland types in Inner Mongolia, Gansu and Sichuan were separated from the protection system. The main wetland types in the middle reaches of the Yellow River were riverine wetlands, with low protection coverage rate and large conservation gaps. After protection network system being optimized, the protection effect was improved by29.1%-37.6%. The wetland in the lower reaches of the Yellow River was mainly concentrated in the Yellow River Delta area. The protection system was good and the conservation gaps was small. Overall, riverine wetlands in the middle reaches of the Yellow River basin had the highest area proportion of conservation gaps which needed more attention. Based on the priority conservation pattern, our results provided scientific suggestions for the protection planning and management of wetlands in the Yellow River basin, which would lay a foundation for the water ecological protection of the Yellow River basin from the macro scale.

This paper presents a new method to simulate the dynamics of multiple land uses based on the integration of neural networks,cellular automata and GIS. Recently, cellular automata (CA) have been increasingly used to simulate urban growth and land use dynamics. However, simulation of multiple land use changes using CA models is difficult because numerous spatial variables and parameters have to be utilized. Conventional CA models have problems in defining simulation parameter values, transition rules and model structures. In this paper, a three-layer neural network with multiple output neurons is designed to calculate conversion probabilities for competing multiple land uses. The neural-network-based CA model is directly developed in a GIS environment by using ARC/INFO GRID AML. The GIS provides both data and spatial analysis functions for constructing the neural network. Real data are conveniently retrieved from the GIS database for calibrating and testing the model. The GIS functions are also used for the neural network calculations. The neural network has multiple output neurons to generate conversion probabilities at each iteration. Land use conversion is decided by comparing the conversion probabilities. The model is carried out by iterative looping the neural network for simulating multiple land use changes. Complex global patterns can be generated from local interactions through the neural network. The simulation results are not deterministic because a stochastic variable is used and site attributes are dynamically updated at the end of each loop. The proposed method can overcome some of the shortcomings of the currently used CA models in simulating complex urban systems and multiple land use changes by significantly reducing the tedious work in defining parameter values, transition rules and model structures. The model has been successfully applied to the simulation of land use dynamics in the Pearl River Delta.

与传统的在景观尺度上对城市扩张占用耕地时空特征及其演变规律的研究不同，论文从微观层面提出基于Agent 的城市扩张占用耕地动态模型（Urban Encroachment on CroplandDynamic Model，UECDM），多角度深入探索耕地向城市用地转变的驱动机理及其时空动态特征，并提出协调二者平衡的可持续发展对策。在UECDM模型中引入视域分析，通过模拟地形和观察点将视觉景观的量化评价结果应用到居民居住区位决策过程，从而分别构建包含可视域的能够更全面表征环境要素及其内部关系的元胞自动机层和不同类型Agent 相互作用的多智能体层，兼顾人类决策行为和城市空间生长自组织性。应用该模型对天津城市扩张占用耕地进行动态模拟研究，并从数量与空间格局两方面展开精度验证，Kappa 系数达到0.795，依据4 个景观格局指数计算得到模拟结果的平均相对误差为3.86%，表明模型具有较高可信度。对不同时期模拟结果的分析表明，天津城市扩张占用耕地空间主要表现为“摊大饼”式外延扩展和跳跃式“卫星城”，研究结果将为未来城市发展规划和耕地保护提供决策支持。

Unlike traditional studies about the spatio-temporal characteristics and its evolution law of urban encroachment on cropland on landscape scale, this paper proposes agent-based Urban Encroachment on Cropland Dynamic Model (UECDM) from the micro-level, exploring in depth the mechanism and dynamics of urban encroachment on cropland from diverse perspectives, so as to bring forward sustainable development countermeasures for reconciling both balance. UECDM introduces viewshed analysis, which applies quantitative assessment results of the visual landscape to residential decision-making processes by simulating terrain and observation point. The model consists of cell automata layer of viewshed to fully characterize the various environmental elements along with their internal relations and agent layer containing the interactions among different kinds of agents, which takes account of human decision-making and self-organization of urban growth. It is applied to simulate and analyze the spatio-temporal dynamics of Tianjin's urban encroachment on cropland and validation follows. The Kappa coefficient is up to 0.795 and based on four landscape indices, the average relative error of the simulation result is about 3.86%, both indicating a high credibility of this model. Analysis of the simulation and prediction results of different periods indicates that the spatial pattern of Tianjin's urban encroachment on cropland is mainly outward expansion of the "pie" type as well as "satellite towns" of the "jump" type, which makes it possible to provide decision support for future urban development planning and cropland protection.

This paper introduces urban land teleconnections as a conceptual framework that explicitly links land changes to underlying urbanization dynamics. We illustrate how three key themes that are currently addressed separately in the urban sustainability and land change literatures can lead to incorrect conclusions and misleading results when they are not examined jointly: the traditional system of land classification that is based on discrete categories and reinforces the false idea of a rural-urban dichotomy; the spatial quantification of land change that is based on place-based relationships, ignoring the connections between distant places, especially between urban functions and rural land uses; and the implicit assumptions about path dependency and sequential land changes that underlie current conceptualizations of land transitions. We then examine several environmental "grand challenges" and discuss how urban land teleconnections could help research communities frame scientific inquiries. Finally, we point to existing analytical approaches that can be used to advance development and application of the concept.

社会经济发展过程中一个国家（地区）森林面积由减少转为增加的“森林转型“内在驱动机制,是资源环境研究关注的热点。以4期卢旺达土地覆盖数据为主要信息源,分析1990—2015年该地区森林变化的趋势和时空特征。结合社会经济数据,借助森林转型的路径分析法,探究卢旺达森林面积变化的影响因素及其所遵循的转型路径。在此基础上,利用PLUS模型对卢旺达2030年的森林空间动态分布进行模拟预测,对如何继续保持良好转型态势提出相关建议。结果表明：①卢旺达森林面积在2010年开始出现净增长,由2010年的197383.2 hm²增加到2015年的213087.8 hm²,年增加率0.8%;②国家公园和保护区是森林增长主要地区,且主要来源于稀树草原和耕地,分别占森林净增加总面积的87.8%和8.8%;③转型的内在驱动机制主要是国家政策引导下发生的“国家森林政策路径”和“森林稀缺路径”,全球化路径体现在植树技术与资金支持;④对卢旺达2030年森林模拟预测显示,森林转型仍将继续,预计到2030年森林面积将净增加34065.2 hm²。为进一步提高研究区森林覆盖率,卢旺达政府部门应改善森林恢复的薄弱环节,加快农业集约化推广;通过为农村社区创造场外就业机会,引导经济和就业发生转型,从而推动基于“经济发展路径”与“农村集约化路径”的森林增加。

In the process of socioeconomic development, the internal driving mechanism of the “forest transition” in which the forest area of a country (region) changes from decreasing to increasing is a hotspot in resources and environment research. This study used Rwanda's land cover data as the main source of information to analyze the trends and temporal and spatial characteristics of forest changes in the country from 1990 to 2015. Using socioeconomic data and the path analysis method of forest transition, this study explored the influencing factors of the change in forest area in Rwanda and the transition paths that it followed. On this basis, the patch-generating land use simulation (PLUS) model was used to simulate and predict the spatial dynamics of Rwanda's forest distribution in 2030, and relevant policy recommendations on healthy forest transition was made. The results indicate that: (1) The forest area of Rwanda began to show a net increase in 2010, from 197383.2 hm2 to 213087.8 hm2, with an annual change rate of 0.8%. (2) The National parks and protected areas were the main areas of forest growth, and the growth were mainly from savanna and cropland, accounting for 87.8% and 8.8% of the total forest net increase respectively. (3) The internal driving mechanism was mainly the “national forest policy path” and the “forest scarcity path” under the guidance of national policies. The path of globalization was reflected in tree planting technology and financial assistance. (4) The simulation result shows that forest transition will continue in Rwanda by 2030. The forest area is expected to increase by 34065.2 hm2. To increase the forest coverage rate, the state should improve the weak links of forest restoration and accelerate the promotion of agricultural intensification. By creating employment opportunities for rural communities, the government can guide the transformation of the economy and employment. The state can promote the “economic development path” and “agricultural intensification path” through the above measures.

城市增长边界（UGBs）能够控制城市空间的无序蔓延并引导城市合理增长,多发展情景下的UGBs是对不同规划条件下城市未来发展空间范围进行界定的常用方法。元胞自动机（CA）模型能对未来城市发展进行动态的预测,并已广泛的应用于UGBs的划定中。然而,目前的方法和模型大多只针对单一的城市发展情景进行UGBs的划定,较少能对未来多种发展情景下的UGBs进行准确划定。因此,针对这个问题本文提出了一种基于未来用地模拟（FLUS）模型和膨胀与腐蚀的算法的多情景UGBs划定模型（FLUS-UGB）。本文选取珠江三角洲地区为研究区,在对2000-2013年珠江三角洲地区城市土地利用进行模拟和验证的基础上（Kappa系数为0.715,总体精度为94.539%）,预测了2013-2050年基准、耕地保护及生态控制3种情景下珠江三角洲地区的城市扩张,并根据预测结果对该地区UGBs进行划定。结果显示,该方法能够针对不同的城市发展情景进行相应UGBs的划定,具有较好的可靠性及适用性。

选取耕地保护“新政”时期的1999-2007 年为研究时段,以耕地面积与粮食产量变化的分歧原因—耕地生产力变化为切入点,通过比较分析、空间与计量分析探寻粮食安全的关键影响因素。结果表明:农民种粮积极性变化决定着耕地集约利用是影响粮食安全的关键;2003-2007 年农民种粮积极性的持续提高主要来自市场粮价的上涨;粮食直补仅在开始实施的年份激发了农民对种粮收益的预期。此外,本文从提高农民种粮积极性、优化粮食生产投入及改进耕地保护模式3方面,提出了耕地保护发展的政策建议。

Exploring the key influencing factors of food security guarantee during the typical period is of significance for the development of cultivated land protection and agricultural policy. This paper aims at exploring the factors between 1999 and 2007 which was in the new period of cultivated land protection administration. Methods such as comparison, spatial and econometric analysis are used to analyze the change in cultivated land productivity which was the cause of the disparity between cultivated land area and grain output changes. Results show that farmers' willingness to grow grain which determines cultivated land use intensity is the key factor. The sustained improvement of the willingness in 2003-2007 was mainly resulted from the rise of grain market price. Meanwhile, direct subsidy merely inspired farmers' anticipation for the profit of grain growing at the beginning years of implementing this policy. In addition, suggestions on the development of cultivated land protection are proposed involving improvement of farmers' willingness to grow grain, optimization of inputs in grain growing and improvement of cultivated land protection models.

粮食安全是保障国家经济发展和社会稳定的基石,日益严峻的耕地非粮化问题加剧了粮食安全风险,直接影响中国社会经济的可持续发展。本文从食物性生产的非粮化角度,选取广东省为研究区域,以县域为评价单元,运用社会经济统计数据及地理空间数据,集成Theil指数、空间自相关模型、随机森林模型、主成分分析和聚类分析等方法,从全省四大区域角度探讨了广东省2005和2019年耕地非粮化的时空演变特征、影响因素及其驱动类型。结果表明：①广东省耕地非粮化率由2005年的48.47%上升至2019年的54.65%,耕地非粮化程度由低度为主转向中度为主,且耕地非粮化利用空间差异呈现缩小态势,以珠三角的演变差异最为显著。②耕地非粮化的空间分布保持稳定的集聚状态,并以珠三角的高高集聚和东翼、西翼、山区的低低集聚为主。③路网密度、地均GDP对耕地非粮化存在显著的推动作用,农村第一产业劳动力占比、各县到省会城市距离是抑制耕地非粮化的重要因素。④耕地非粮化驱动类型以经济驱动型为主(44.63%),主要分布在珠三角;其次是农业支持型(33.06%),大多分布在山区;资源依赖型占比最少(22.31%),集聚在东、西两翼。研究结果有利于精准识别广东省耕地非粮化的时空特征,提升当地耕地非粮化的风险管控水平,对于农业可持续发展以及保证地区的粮食安全具有重要的理论与现实意义。

Food security is the cornerstone of national economic development and social stability. The increasingly serious problem of cultivated land non-grain conversion intensifies the risk of food insecurity and directly affects the sustainable development of China's social and economic systems. From the perspective of non-grain production of food, this study selected Guangdong Province as the research area and county as the evaluation unit and based on socioeconomic statistics and geospatial data, using Theil index, spatial autocorrelation model, random forest model, principal component analysis, and cluster analysis to examine the spatiotemporal characteristics, influencing factors, and driving types of cultivated land non-grain conversion in 2005 and 2019. The results show that: (1) The non-grain rate of cultivated land in Guangdong Province increased from 48.47% in 2005 to 54.65% in 2019. The non-grain degree of cultivated land had changed from low to moderate, and the spatial differentiation of non-grain rate of cultivated land showed a decreasing trend, especially in the Pearl River Delta area. (2) The spatial distribution of non-grain cultivated land maintained a stable agglomeration state and showed high concentration in the Pearl River Delta area and low concentration in the east wing, west wing, and mountainous sub-regions of the province. (3) Road network density and GDP per square kilometer had significant promoting effects on cultivated land non-grain conversion, while the proportion of labor force in rural primary industry and distance between counties and provincial capital cities were important factors to restrain the cultivated land non-grain conversion. (4) The main driving type of cultivated land non-grain conversion was economy driven (44.63%), mainly distributed in the Pearl River Delta area. This was followed by agriculture supporting type (33.06%), mostly distributed in the mountainous areas. The resource dependency type was the least dominant (22.31%) and was concentrated in the east and west wing sub-regions. This research result is conducive to accurately identify the spatiotemporal characteristics of cultivated land non-grain conversion in Guangdong Province, improve the risk control level of local cultivated land non-grain conversion, and has important theoretical and practical significance for sustainable agricultural development and ensuring regional food security.

农业多功能性指农业除了具有生产食物及纤维这一传统功能之外，还具有其他经济、社会、环境及文化等独特的非商品生产功能。农业多功能性在概念提出后得到了研究者和政策制定者的广泛关注，国际组织和相关国家也开展了相关研究，并利用该理论指导其自身的农业发展。由于自然条件和人类活动的影响，农业文化遗产地多具有生态环境脆弱、民族文化丰富、经济发展落后等特点，农业的多功能特征表现的更为明显，其农业同时肩负着生产、生态、文化等功能。因此对农业文化遗产地的农业多功能性分析，有利于全面认识其价值，并为农业发展提供指导。本文构建了农业文化遗产地农业多功能性评价模型，并对全球重要农业文化遗产首批试点浙江省青田县进行了定量评价。青田县农业功能评价结果排序为生态环境保护功能0.86、景观保留功能0.83、文化传承功能0.53、产品生产功能0.32、生物多样性保护功能0.27，运用多维模型得出农业多功能性综合评价值为0.64。

Multifunctionality in agriculture refers to the non-trade benefits of agriculture, that is, benefits other then commerce and food production such as environmental protection, landscape preservation, rural employment, and food security in terms of the WTO definition. Due to specific natural conditions and human activities, agricultural heritage sites always have a fragile ecological environment, rich cultures, undeveloped economy as well as multifunctionality in agriculture. This means that agricultural heritage sites have production, ecological, cultural and other functions. To that end, recognizing and evaluating multifunctionality of agriculture at agricultural heritage sites would be conducive to a comprehensive understanding of the value of the agricultural heritage, and in turn to providing guidance for agricultural development. Based on the definition of multifunctionality of agriculture at agricultural heritage sites, the authors established evaluation models for agricultural multifunctionality at agricultural heritage sites and examined Qingtian County in Zhejiang Province, the first pilot site of Globally Agricultural Heritage Systems selected by FAO in 2005. Multifunctionality of agriculture at agricultural heritage sites can reflect essentially in five aspects, i.e., the food production, agricultural biodiversity conservation, traditional agricultural knowledge system and culture conservation, agro-ecological environmental protection and agricultural landscape conservation. The value of the food production function is determined by the guaranteed rate of per capita grain and equivalent per capita arable land area. The value of agricultural biodiversity conservation function can be determined by the diversity of traditional rice varieties. The value of traditional agricultural knowledge system and culture conservation is determined by the importance of intangible culture heritage. The value of agro-ecological environmental protection is determined by fertilizer and pesticide intensity and Eco-environmental Quality Index (EQI). The value of landscape conservation is determined by the tourism revenue. Evaluation results indicated that Qingtian County showed the highest value of 0.86 in agro-ecological environmental protection and an agricultural landscapes conservation value of 0.83, but it had the lowest value of 0.27 in agricultural biodiversity conservation. Using a multi-dimensional model, the comprehensive value of multifunctionality in agriculture in Qingtian County was found to be 0.641. Qingtian County has a long history of raising fish in rice paddies and has been maintaining the traditional rice-fish system exemplified in traditional ecological agriculture. The government and people there have been dedicating to developing green rice-fish products and agricultural tourism, thereby resulting in the highest value of agro-ecological environmental protection and agricultural landscapes conservation. Located in the eastern developed areas in China, there are limited planting areas for traditional rice varieties.

将土地因素引入水—能源—粮食系统,运用耦合协调模型对京津冀城市群2005— 2018年水—能源—粮食—土地系统的时空变化特征进行研究。结果表明：（1）从空间尺度上来看,京津冀城市群建设用地由中心向四周扩散;从京津冀城市群土地利用格局来看,耕地和建设用地面积分别呈现较为明显的下降和增长趋势。（2）将土地纳入水—能源—粮食系统降低了京津冀城市群大多数城市水—能源—粮食系统间的耦合度和耦合协调度。（3）土地与水—能源—粮食子系统组成的两要素系统的协调水平会进行叠加或抵消进而影响水—能源—粮食—土地系统耦合协调度。本文的研究启示在于：京津冀城市群在考虑水、能源、粮食协调发展的同时,应考虑土地对水—能源—粮食系统整体及内部子系统的影响,根据城市自身资源优势合理配置资源、优化产业布局以实现可持续发展。

In this paper, the land factor is introduced into the water-energy-food system, and the coupling coordination model is used to study the spatio-temporal change characteristics of the water-energy-food-land system in the Beijing-Tianjin-Hebei Urban Agglomeration from 2004 to 2017. The results show that: (1) On the spatial scale, the construction land of the study area diffuses from the center to the periphery. In terms of land use pattern of the urban agglomeration, the area of cultivated land and construction land showed a relatively obvious decline and growth trend, respectively. (2) The integration of land into the water-energy-food system reduces the coupling degree and co-scheduling of water-energy-food systems in most cities of this urban agglomeration. (3) The coordination level of land and water-energy-food subsystem will be superimposed or offset, which will affect the coupling coordination of water-energy-food-land system. The research enlightenment of this paper is that considering the coordinated development of water, energy and grain, the Beijing-Tianjin-Hebei Urban Agglomeration should understand the impact of land on the whole and internal subsystems of the water-energy-food system, allocate resources reasonably and optimize the industrial layout according to the city's own resource advantages, so as to achieve sustainable development.

耕地撂荒严重地影响着我国的粮食安全。以我国粮食主产区为研究区域,在识别撂荒地分布的基础上,测度了撂荒地空间分布格局,并建立耕地撂荒中介效应模型,探究了耕地撂荒对区域粮食产量的影响机制。结果表明：（1）中国粮食主产区耕地撂荒规模为405.53万hm²,撂荒率约为5.85%;空间上撂荒地规模分布呈“T”字形空间格局,黑龙江东北部、吉林西北部以及内蒙古南部地区为撂荒地主要集聚区。（2）耕地撂荒对于粮食主产区粮食产量具有显著负向影响,2017年我国粮食主产区因耕地撂荒损失的农田生产潜力达到1339.15万t,损失的粮食产量高达2265.6万t,损失比例达4.69%;内蒙古自治区成为粮食产出损失量和损失比例最大的地区。（3）粮食播种面积、农田生产潜力和农业技术投入均发挥了部分中介作用,系数分别为-0.194、-0.025和0.006。（4）应遵从城乡融合以及农业农村发展态势,强化粮食主产区农业生产现代要素投入与政策扶植,构建粮食生产—耕地休耕空间转换弹性机制,保障我国粮食安全。