Reversing food desertification: examining urban farming in Louisville,Chicago and Detroit

The Urban Farming Movement is relatively young in Louisville, Kentucky but it seems to be off to a good start. Being in its earliest stages, assessments of this effort must be made cautiously, even tentatively. Examining a movement that is in progress requires a study of the state's land use and segregation policies, both of which have been dynamic in Kentucky. Further, this study is also relevant as there is a growing convergence of national and regional attitudes towards American obesity, while there are competing notions of food preference and food choice. All of which are influenced by racial politics, and there is a deep concern regarding food security. Considering all of these, it is necessary to examine the Government's efforts to address obesity/food imbalance in a variety of settings, especially where urban farming is expanding, such as Chicago and Detroit. In New York, roof-top gardens dot the landscape and the urban farm movement is largely a “success”. So, city leaders have chosen to address another health issue – trans fat. Rather than joining the food choice/preference debate by banning fast-food restaurants, city leaders have chosen to enact a trans-fat ban. Unpopular at first, other cities and states have followed, and the Federal Government will mandate a trans-fat ban this year. In Louisville, Chicago and Detroit, where the trans-fat bans did not succeed, the urban farm movement may be the primary means of addressing malnutrition, in the form of obesity.     

Local food networks as catalysts for food policy change to improve health and build the economy

Local food networks (LFNs) are growing in popularity, in part as a response to broader criticisms of conventional food production. Municipal policy-makers have the opportunity to work with stakeholders to build LFNs to increase access to healthy foods in cities and ultimately improve population health and well-being. Building opportunities for healthy eating is particularly important in our study area. Flint, Michigan, is a post-industrial shrinking city suffering from the economic and health effects of deindustrialisation. Various stakeholders in Flint have responded to a significant issue with access to food by strengthening collaborations through a food policy council (FPC). Growth in the local food system has been supported by administrators and community advocates alike, through supporting community gardens, farmers' markets, and urban agriculture in a manner similar to nearby Detroit. Participant observation was conducted with stakeholders involved in the development of the LFN and the FPC in Flint. Stakeholders were exposed to existing research on the food system to help inform their policy direction. The group expressed several core concerns and prospects for future work, including a strong emphasis on consensus-based decision-making. Based on the synthesis of stakeholder opinions, policy recommendations are made to aid in continued planning of the LFN. Planning for food is an important first step in improving public health and strengthening local economic development in post-industrial cities. This research highlights the issue by making explicit the challenges and opportunities for policy advocacy in LFNs.     

Land take and food security: assessment of land take on the agricultural production in Europe

Soil is a multifunctional, non-renewable natural resource for Europe as clearly expressed in the European Union (EU) Thematic Strategy for Soil Protection (COM (2006)231). Soil carries out multiple functions, including the support of food production. Urban development and its associated land take poses a major threat to soil and could have significant effects on agricultural production. This paper aims to evaluate the potential productivity losses in European agriculture due to land-take processes between 1990 and 2006. Agricultural land take was calculated using CORINE Land Cover maps of 1990, 2000 and 2006. For 21 of the 27 EU member states, agricultural land take was computed to be 752,973 ha for 1990–2000 and 436,095 ha for 2000–2006, representing 70.8% and 53.5%, respectively, of the total EU land take for these periods. The impact of this land take on the production capabilities of the agricultural sector for the period 1990–2006 for 19 of the 21 states was estimated to be equivalent to a loss of more than six million tonnes of wheat. The paper demonstrates that Europe's intense urbanisation has a direct impact on its capability to produce food.     

基于多种空间静态指标的土地生态安全评价——以精河县为例

生态安全是区域可持续发展的核心问题,是地区安全和社会稳定的重要组成部分。以精河县为例,综合应用数字高程模型(DEM)、TM遥感数据和各种数据,在地理信息系统(GIS)支持下建立了生态安全指标体系。结果表明,1)精河县生态安全水平呈现明显的空间差异性,整体由中部绿洲向周边逐渐降低。2)从空间分布来说,研究区中部的土地生态安全要优于北部和南部,中部大部分土地处于安全和临界安全状态;南部山地土地生态安全类型分布零散,临界安全区、安全区交叉分布;极不安全和临界安全区集中在艾比湖周围、古尔班通古特沙漠及南部山区;很安全区所占比重较小,集中在绿洲内部。3)1998年和2013年各生态安全等级分布面积由大到小排序为生态安全区、生态临界安全区、生态极不安全区、生态很安全区。研究表明,精河县土地生态状况整体良好,与实际情况相符合。今后应加强土地利用结构优化,减少水土流失与土壤的盐渍化,保证土地生态系统健康稳定。     

基于安全度的机场围界安全评估方法

针对机场围界存在虚警率高、信息分散和难以从全局角度管理等问题,提出基于安全度的机场围界安全评估方法。基于分散环境集中监控思想,利用改进DS证据理论将前端探测设备获取的信息进行融合,再利用模糊集理论获得区段安全度,进而求得防区安全度和全局安全度。基于C#和Map Xtreme开发机场围界监控平台,结果表明,基于安全度的评估方法能够准确反映机场围界安全运行状况。     

南水北调中线干渠生态系统结构与功能分析

为分析和掌握南水北调中线干渠生态系统结构与功能的特征参数,根据2015~2019年中线干渠鱼类资源调查数据及实测的鱼类生物学参数数据,应用Ecopath with Ecosim 6.6软件构建了Ecopath食物网模型.模型由18个功能组组成,包括了初级生产者、初级消费者、主要鱼类和有机碎屑等.结果显示：中线干渠生态系统规模总流量、总生产量和总消耗量分别为19186.330,8947.857和1106.002（t/（km²·a））,食物网主要由4个整合营养级（1.00~3.71）构成,最高营养级为大型肉食性鱼类鱤（3.71）.食物网能量传递主要有两条途径,分别为牧食食物链和碎屑食物链,两者传递的能量相当,但牧食食物链传递效率是碎屑食物链的近两倍.交互营养分析结果表明,捕食者对其饵料生物的影响一般为抑制作用,碎屑生物量的增加对大部分功能组的影响为正效应,小型上层鱼类对浮游动物生物量起抑制作用.从各功能组之间的生态位重叠来看,各功能组间捕食者生态位重叠现象不普遍,重叠指数适中,部分肉食性鱼类的捕食者生态位重叠指数达到1.对生态系统总体特征分析发现,中线干渠生态系统的总初级生产量与总呼吸量的比值（P/R）、总初级生产量与总生物量的比值（P/B）、Finn's循环指数（FCI）和Finn's平均路径长度（FML）都表明该生态系统处于发展的幼态期,抵抗外界干扰的能力差.此外,中线干渠生态系统对初级生产力的利用率很低,导致过多的营养物质未进入更高营养级的食物链中进行循环,造成系统能量流动的滞缓.因此,根据生物操纵理论,可通过优化和完善鱼类群落结构,增强对系统初级生产力的利用效率,促进物质循环和能量流动,维持生态系统稳定.     

长江流域生态系统可持续管理策略

长江流域涉及长江经济带发展和长三角一体化发展两大国家区域协调发展战略,但生态环境问题仍然是长江流域可持续发展面临的严峻挑战,加强长江流域生态系统可持续管理策略研究具有重大意义.长江流域的环境管理策略大致经历了以水量管理、污染物排放总量管理和水质目标管理三个阶段.在统一生态环境监管职能、实现五个“打通”的新形势下,长江流域生态环境管理策略必将由水质目标管理快速向生态系统可持续管理转变.在分析长江流域生态系统保护修复取得的积极进展和面临的严峻形势的基础上,提出了长江流域生态系统可持续管理策略:①规划和建设服务于应急预警和管理决策的长江生态系统观测网络,推动不同层级、不同职能部门、空天地一体化的多源数据融合,提高生态环境监测网络的数据时空精度和反应速度,开展水陆统筹、“山水林田湖草”生命共同体综合观测;②加强长江生态系统结构、过程、功能和服务的综合性、整体性研究,主要开展长江流域生态系统综合研究、重点区域生态系统研究和突出生态问题专题研究,不断创新科研与管理深度融合的科研模式,把论文写在祖国大地上;③制定长江社会-经济-自然复合生态系统保护修复可持续发展目标及分阶段分区域目标,促进水资源、水环境、水生态、陆域生态和水陆交错带的持续改善以及生态环境系统与社会经济系统的持续协同;④提出长江生态系统保护修复的整体性、综合性和针对性、差异化的解决方案,推动长江流域生态系统健康可持续发展目标的早日实现和重点区域、突出问题的尽快解决.      

国外食物系统研究综述及借鉴

食物关系到国计民生,食物的高效供给取决于食物系统的高效运转。目前国内食物系统视角的研究不足,系统梳理国外研究进展对我国食物系统研究具有积极的借鉴意义。为了更好地把握食物系统的研究脉络,论文通过对国外食物系统研究文献进行研读,在总结分析食物系统研究相关理论和方法的基础上,着重对食物系统的全球化与本地化、食物系统规划、食物系统的资源环境效应、食物安全与政策研究等问题进行了系统梳理。在借鉴国外食物系统研究的基础上,结合已有的研究基础和社会需求,提出未来我国食物系统领域的研究展望,包括开展不同尺度的食物系统实证研究、开展跨学科多领域的共同研究、食物系统定量指标体系设计问题研究、食物系统的利益相关者研究以及加强技术创新对食物系统的影响研究等。     

中国优势金属供应全球需求的风险评估

随着新一轮科技革命和产业转型的发展,全球金属资源供需格局发生重大调整,美国、欧盟、日本等主要发达国家不断倒逼中国敞开优势金属供应。为保障国家金属资源安全,论文从可依赖性、可持续性、可承受性3个维度建立了一套金属资源供应风险评估体系,对中国优势金属供应全球需求的风险进行评估,结果表明：1）中国优势金属整体供应风险较高,铟、铋等两种金属风险值都在80以上,处于高风险水平;锑、锗、钡、镁、钨、稀土等6种金属风险值都是60~80之间,处于中高风险水平;镓、锶等两种金属处于中风险水平。2）在10种中国优势金属中,钡的可依赖性风险最高,达到81.88,稀土的风险最低,只有42.42。铟的可持续性风险最高,达到81.80;锑的最低,风险值为69.46。铟的可承受性风险也最高,高达100;铋的次之,风险值为89.23;钡的最低,只有33.96。3）随着未来新兴产业的快速发展,中国优势金属的供应风险将更加严峻。     

区域农田当量供需能力分析及其政策启示——以浙江舟山市为例

“以粮为纲”的食物安全观,使中国在实施耕地占补平衡政策过程中,片面追求耕地占补的数量平衡对食物安全的保障作用,而忽视了耕地以外的用地类型对区域食物安全的作用,不仅导致补充耕地的质量与占用耕地的质量不可同日而语,而且由于盲目对草地、林地、滩涂湿地等进行开发而付出了沉重的生态环境代价。论文从食物安全的内涵出发,引入农田当量与食物当量概念,选取浙江省舟山市为研究区,对研究区农田当量的供需能力进行实证分析,并为耕地占补平衡政策的改进提出相应的政策启示。研究结果表明：1）采用农田当量与食物当量的计算方法,可以较好地统一粮食产量和养殖水产品产量的食物当量,进而统一耕地与养殖水面的农田当量供给。2）受耕地面积减少和耕地抛荒比例较高等因素影响,近年研究区来自耕地的农田当量下降了37.3%;与此同时,尽管研究区养殖水面面积也在不断缩减,但受标准养殖塘建设、养殖技术进步以及品种改进等因素的影响,来自养殖水面的总农田当量上升了18.3%。来自耕地和养殖水面的总农田当量的比例,由2009年的46:54变为2015年的31:69。3）在温饱、小康和富裕3个不同生活水准下,研究区本地耕地和养殖水面提供的农田当量,都难以满足常住人口的需求,但是,通过改善农田基础设施、提高耕地复种指数,建设高标准养殖塘、提高养殖水面单产等措施,可以提高耕地和养殖水面的农田当量至19 771.22 hm²,进而降低约35%的农田当量缺口。在此基础上,论文得到转变食物安全观念,重视耕地以外的用地类型的食物供给能力;推进高标准农田和高标准养殖塘建设,提高耕地和养殖塘的农田当量供给能力;加大耕地保护力度,探索耕地占补平衡的多样化实现形式等政策启示。