陕西省人口分布的空间特征及其演变趋势

随着社会经济的不断发展,陕西省人口分布发生了明显变化.探究这种变化特征和趋势对协调区域人口的合理分布具有重要意义.采用空间自相关、人口结构指数、人口重心等研究方法,以陕西省97个县级行政区为研究单元、1990-2010年为研究区间,选取人口数和人口密度为研究对象,对陕西省人口分布的空间特征及其演变趋势进行了描述.结果表明,陕西省人口分布存在“中间高—南北低”的格局,人口密度空间分布呈正的空间相关性,人口集聚性较强.随着时间推移,集聚性趋势略有减弱,人口分布的不均衡性较显著,表现出上升趋势;人口重心向东北方向移动,移动速度有所加快.     

关中地区地震灾害宏观人口脆弱性评估

地震灾害人口脆弱性研究对减少地震灾害损失和提高应对灾害能力具有一定的现实意义。构建关于人口的生理、社会、经济三方面的指标体系,通过熵值法计算评价指标权重,采用综合指数法计算各地区地震灾害人口脆弱性指数,绘制聚类系谱图和地震灾害人口脆弱性空间分异图,对关中地区各区县地震灾害宏观人口脆弱性进行评估。结果表明:关中地区地震灾害人口脆弱性具有明显的空间分异性,脆弱性高的区域主要分布在渭河平原地区,脆弱性低的区域主要分布在秦岭山区、渭北旱原,整个区域脆弱性总体比较低;人口密度是地震灾害人口脆弱性的主要影响因素,并且综合其他因素共同影响地震灾害宏观人口脆弱性。     

20年来安徽省人口时空分布特征分析

在GIS技术支持下,建立安徽省人口地理数据库,使用密度分析法、重心分析法和空间自相关分析法对安徽省1990—2012年人口时空分布特征进行了分析。结果显示,全省人口密度总体上呈由北向南递减分布格局,皖北地区人口密度呈增加趋势,皖南人口密度相对稳定,人口重心位于几何重心的西北方向,20年来人口重心从长丰县沿西北方向移动到寿县境内。全省各县(市)人口密度存在空间正相关性,且随时间推移逐渐减弱。     

沈阳市大型连锁超市空间布局及影响因素研究

运用核密度估计和空间分布均衡度相关分析方法,分析了沈阳市大型连锁超市的空间分布和集聚特征,引入多元回归分析法进一步探析了其空间分异的影响因素和各因子的重要程度。结果表明,沈阳市大型连锁超市整体上呈现出"北多南少"的空间差异分布;核密度空间分布总体表现为二环内区域大面积组团状的核分布与二环以外地区小面积的零星核分布并存;在研究区域内呈现空间集聚分布特征,但在各个市辖区内分布不均衡;空间分异主要受等级公路密度、人口密度、城镇居民人均可支配收入、家庭户户数等因素的影响。     

中国省际传统经济效率与绿色经济效率时空演变分析

基于2000—2013年中国省际面板数据,通过运用考虑非期望产出的SBM模型,分别测算了我国各省市区传统经济效率与绿色经效率,分析了差异与演化趋势。通过建立空间邻接矩阵,测度了我国各地区经济效率在空间上的自相关特性。研究发现:12000—2013年我国传统的经济效率平均值为0.619,显著高于平均值为0.494的绿色经济效率。2我国各地区传统经济和绿色经济效率在空间分布上都存在非常显著的差异。3各地区两种经济效率都存在显著的空间自相关,传统经济效率高高值集聚区域主要分布在我国东部沿海地区,绿色经济效率高高集聚主要分布在我国中东部沿海地区,两者低低值集聚区域主要分布在我国西部地区和中北部地区。     

山东省县域人口—经济空间分异与动态变化研究

运用集中度指数、探索性空间数据分析、重心分析法、不一致指数等方法,探究了2001—2016年山东省137个县域单元人口和经济空间分异与动态变化状况。结果表明:(1)山东省人口集中度指数整体呈现西南高、东北低的分布格局,并出现集聚趋势,经济集中度指数分布格局呈现"双核"模式,高水平经济区具有强大的辐射效应,出现极化现象;(2)山东省人口集聚趋势大于经济的集聚趋势,但经济空间分布的不均衡性仍大于人口,人口和经济集中度在空间上相邻县域间存在着较高的正相关性;(3)山东省人口重心和经济重心都偏离几何重心向西南方向移动,人口重心的移动距离大于经济重心;(4)山东省人口与经济空间匹配类型中协调发展型县域数量下降,经济滞后型县域数量上升。根据研究结果提出山东省人口和经济发展空间优化建议,对统筹区域协调和促进区域可持续发展提供参考借鉴。     

基于GIS的关中地区人居环境自然适宜性研究

选取地形、气候、水文、植被等自然因子,建立1km×1km栅格单元的人居环境基础数据库,构建了基于人居环境指数的关中地区人居环境自然适宜性评价模型.并采用GIS技术定量评价了关中地区的人居环境自然适宜性,揭示了关中地区人居环境的自然格局与地域特征.研究表明,关中地区人居环境指数整体呈现由南向北递减趋势,人居环境指数可综合反映区域人居环境的自然适宜程度,关中地区人口明显集中分布于人居环境适宜程度较高的地区.评价结果显示,关中地区人居环境一般适宜区和比较适宜区面积最大,约5.5489×104km2,接近全区总面积的99.98%,相应人口约为2294.95万人,占全区总人口的99.98%;人居环境临界适宜地区8km2,占全区总面积的0.02%,相应人口2200人,零星分布在陇县西北的黄土高原地区;关中地区人居环境高度适宜地区面积3km2,人口1400人,由于适宜度高、面积小,导致人口密度最大,达467人/km2.     

乡村基本公共服务均等化测度及其与区域经济的时空耦合特征——以安徽省为例

乡村基本公共服务设施落后是乡村振兴的短板,实现乡村基本公共服务均等化是乡村振兴的基础。从教育、医疗卫生、基础设施、社会保障、文化和信息化6个方面综合测度安徽省乡村基本公共服务均等化指数,进一步利用双变量空间自相关方法,揭示均等化指数的空间分布规律及其与区域经济的时空耦合特征。研究发现:安徽省各地区乡村基本公共服务均等化指数总体不高,空间分布差异明显,皖北、皖中地区乡村基本公共服务均等化指数较高,皖南地区相对较低。总体而言,安徽省各地区乡村基本公共服务指数和区域经济耦合程度较低,大部分地区属于HL与LL区。基于双变量ESDA分析结果,为安徽省各地区乡村发展提供建议。     

全域旅游背景下福州市休闲旅游资源空间分异及成因

基于福州市市域休闲旅游资源兴趣点POI数据,分析了该市休闲旅游资源空间分异特征,并探讨了其影响因素。结果表明:①福州市休闲旅游空间分布集聚特征显著,呈现多中心的分布形态,市中心及周边区域形成休闲旅游资源的空间热点区,外围区域相对分散。②全域范围内各乡镇专业化休闲旅游空间差异显著,部分乡镇比较优势突出。③各类型休闲旅游资源空间集聚表现有所不同,随空间尺度范围增大,各类型总体呈现单峰式的集聚分布,集聚程度先增后减。④休闲旅游资源的空间发展差异主要受城镇化发展水平、居民可支配收入、人口密度等因素的影响。     

基于Moran’s I指数的京津冀地区PM2.5空间自相关分析

选取2014~2018年京津冀地区环境监测站点PM_2.5浓度观测数据,基于Moran's I指数,分析了该地区PM_2.5浓度的时空变化特征以及空间相关性。研究表明:2014~2018年京津冀地区PM_2.5浓度空间分布差异显著,2014年良、轻度、中度污染面积约占1/3,降至2018年以“良”为主;PM_2.5浓度空间分布北部、西部优于南部、东部地区,山区优于平原地区;PM_2.5浓度年平均值、IQR、Q1、Q3值及标准差均呈下降趋势,达到且接近于“良”以上程度的站点,从2014年2成增长至2018年8成;通过对历年及各月PM_2.5浓度全局Moran's I指数分析,I值(除7月外)均超过0.5,生成的P值均小于显著水平0.01,Z得分均超过了临界值2.58;年、月平均值均呈显著的集聚效应,年值集聚效应呈减弱趋势,月值集聚效应秋、冬季大于春、夏季,空间集聚效应与污染程度呈显著正相关;局部空间自相关历年、各月H-H集聚主要出现在京津冀南部地区,L-L集聚主要出现在北部地区。京津冀地区PM_2.5浓度值分布存在空间异质性,主要影响因素为地理、气候和经济环境。     

AN APPLICATION RUNOFF MODEL STRATEGY FOR UNGAGED WATERSHEDS1

ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m²) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft³/sec (0.085 to 3.34 m³/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.     

Biodiversity and biotechnology

The maintenance of biodiversity is urged from many quarters and on grounds ranging from aesthetic considerations to its usefulness, particularly for biotechnology. But regardless of the grounds for preserving biodiversity, writers are generally in agreement that it should be preserved. But, in examining the various references biodiversity, such as species diversity, genetic diversity, and habitat diversity, it is apparent that we cannot aim to preserve biodiversityas such, since there are a number of conflicts in any such undertaking. In preserving one aspect of biodiversity, we damage another aspect. Five arguments which attempt to ground our moral concern for biodiversity are reviewed and critiqued, not only for their consistency but also for their power to move us to action. The final section of the paper shows how conflicts in the values of personal and environmental health can impair ethical action and especially policy formation.An earlier version of this paper was read at the conference on Agriculture, Food, and Human Values: Tradition and Change, Orlando, Florida, October 7–9, 1987.     

Journalists' views of advertiser pressures on agricultural news

All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.     

A Social Contract for Biotechnology: Shared Visions for Risky Technologies?

Future technological developmentsconcerning food, agriculture, and theenvironment face a gulf of social legitimationfrom a skeptical public and media, in the wakeof the crises of BSE, GM food, and foot andmouth disease in the UK (House of Lords, 2000). Keyethical issues were ignored by the bioindustry,regulators, and the Government, leaving alegacy of distrust. The paper examinesagricultural biotechnology in terms of a socialcontract, whose conditions would have to be fulfilled togain acceptance of novel applications. Variouscurrent and future GM applications areevaluated against these conditions. Successwould depend critically on how far a sharedvision can be found with the public. Tore-establish trust, significant changes areidentified in the planning and pursuit ofbiotechnology.