Extraction and analysis of abandoned farmland: A case study of Qingyun and Wudi counties in Shandong Province

Journal of Geographical Sciences - Rapid urbanization and continuous loss of rural labor force has resulted in abandonment of large areas of farmland in some regions of China. Remote sensing...     

撂荒耕地的提取与分析——以山东省庆云县和无棣县为例

由于城镇化的快速发展和农村劳动力不断流失,中国部分地区出现大面积的撂荒现象。利用遥感技术可以间接提取撂荒耕地的规模和数量,对耕地的保护和粮食安全有重要意义。以山东省庆云县和无棣县为研究区,基于Landsat数据和HJ1A数据,采用CART决策树分类方法,制作了1990-2017年的土地利用图,制定了撂荒地的识别规则,在此基础之上提取了研究区的撂荒地空间分布、持续撂荒时间分布和撂荒地复垦区域。结果显示：1990-2017年基准期影像的CART决策树分类精度高于85%;1992-2017年间,研究区撂荒地面积最大值为5503.86 hm²,最大撂荒率为5.37%,其中1996-1998年撂荒率最高,2006-2017年撂荒地面积的整体趋势逐年降低;1992-2017年间最大持续撂荒时间为15年,大部分耕地持续撂荒时间在4年之内,少数耕地持续撂荒时间超过10年;1993-2017年撂荒耕地复垦面积最大为2022.3 hm²,最小复垦面积约为20 hm²,复垦率最大值为67.44%,年均复垦率为31.83%。研究结果不仅能够为研究区撂荒驱动因素分析提供数据支撑,而且也可以为其他地区的撂荒耕地识别提供参考。     

Evaluating the impact of two energy conservation programmes in a midwestern city

This paper presents a general methodology for evaluating energy conservation programmes, and uses the methodology to assess a home audit and an energy tax credit programme. The data base contains utility bill histories, audit forms, and personal surveys for 319 Decatur, Illinois homeowners. These data enable analysis of the extent of adoption of the two programmes; characteristics of adopters and non-adopters; the role of information in the adoption process; the actions prompted by the programmes; and the impact of the programmes on residential energy consumption.Adopters of the programmes are found to be better educated, wealthier, have newer homes, and engage in more conservation practices than non-adopters. Lack of information is one barrier to programme adoption, with adopters receiving more useful information from the local utility company and government sources. The programmes appear to have prompted certain conservation practices, but they have not reduced energy consumption. Policy implications are discussed.     

Modelling of geographic cancer risk factor disparities in US counties

The goal of this research is to create a theoretical framework for the identification of cancer risk factor disparities and address the recognition of geographic patterns in these factors. 34 secondary variables covering the entire US at the county level in 2010 were analyzed, both individually and grouped (theoretically and statistically), in relation to the mortality to incidence ratio (MIR) for all cancer sites. An a priori assessment and a principal components analysis (PCA) were used to group variables to test societal constructs. OLS and geographically weighted regressions (GWRs) were used to assess influence of both individual and grouped variables against the MIR. The theoretical grouping of variables showed little change in predictive capability of OLS models. In GWR model, there was marked improvement over the OLS. Maps produced using local R2 showed clear regional patterns of influence between the indicators and the MIR. Both the theoretical model and the justification for a spatial approach to cancer risk factor disparities were shown to be effective in this paper. The link between this suite of indicators and the health outcomes is clear, and supports the idea that a full representation of the SES landscape should be used to both predict health outcomes and to assess policy options for improving these outcomes. With the presence of definitive regional patterns and clear connections between the MIR and societal groupings, the findings from this research suggest a need to shift to a more comprehensive and spatial approach to cancer disparities research.     

Spatial spillover and the socio-ecological determinants of diabetes-related mortality across US counties

The spatial structure of diabetes-related mortality in US counties is evident from previous studies. However, it is not clear if spatial variation in diabetes-related mortality is associated with spatial variation in socioecological factors. We analyze the spatial spillover effect of changes in socioeconomic gradients (education, employment, household income), retail food environments, and access to health care, on diabetes-related mortality rates across the United States. Seven-year aggregates of multiple cause mortality data from the CDC WONDER compressed mortality database were merged with several sources of county-level data to examine mortality clusters, factors associated with the clusters, and spatial spillover effects in 3109 continuous US counties. The results suggest that high diabetes-related mortality cluster counties are located throughout the Southern Plains, Southeastern, and Appalachian regions. Lower socioeconomic status, a high density of fast food restaurants, a lack of access to grocery stores, a high proportion of Blacks, and low physical activity characterize high diabetes-related mortality rates clusters. The impacts from improvements in socioeconomic gradients and the retail food environment in neighboring counties spill over, and reduce the diabetes-related mortality rate in a particular county. This result implies that improvements in socioeconomic status and access to healthy food would significantly reduce diabetes-related mortality rates in contiguous US counties.     

江苏省典型县域村镇建设格局演化模式

城乡中国转型过程中村镇呈现异质化发展态势。然而当前研究较多关注了村镇物质空间演变特征,忽视了其背后社会经济形态变迁对村镇建设格局的形塑作用。本文以提炼不同发展路径下的县域村镇建设格局演化模式特征为目标,首先从“社会过程—空间形式”视角,剖析村镇建设格局演化路径分化逻辑,并梳理其分化历程;其次采用多案例研究方法,对比分析2009—2018年江苏省3个典型县域的村镇建设格局演化差异;最后将其归纳为具有一定普适意义的演化模式。结果表明：村镇建设格局演化是典型的空间生产过程,在城乡中国转型过程中,生产方式的转变引致村镇建设格局演化路径呈现多元分化;由于要素集聚与疏散的空间需求不同,不同发展路径下的县域村镇建设格局演化时空特征、影响因素作用机制具有显著差异。基于案例比较分析,本文总结出具有差异化演化态势及动力机制的3类演化模式,分别为城乡两极分化的农业生产型、城镇多中心扩张的工业生产型、村庄走向分野的生态消费型,并提出了相应的针对性措施,因地制宜推进城乡融合发展。     

Local and global in cyberspace: the geographical narratives of US food companies on the internet

Summary Internet websites provide a new are na in which companies can create images and representations with attendant geographical narratives. A case study of the websites of the 20 largest US-headquartered food, beverage and food service companies reveals an extensive use of geographical narratives that play on the particular spatial dimensions of the internet. The websites of many of these companies attempt to project and situate corporate activities within a stylized representation of the local and the global, thus providing a 'space' for corporate discourse within cyberspace. Insights gained from this case study highlight the importance of geography and geographical metaphors within the discursive lives of companies. The paper concludes that corporate websites portray idealized identities within idealized geographies.     

经济欠发达地区县域发展模式与战略--以河南省兰考县为例

经济欠发达地区的区域发展模式与城市化推进问题历来是区域研究中的一个难点。本文以河南省兰考县为例,首先结合新区域形象的建设探讨了欠发达地区以县城为主导的县域发展模式;继而,基于大量的实地调查,提炼出欠发达地区县域乡村发展的若干模式:多元化产业联动发展模式,能人富户带动发展模式,政府协调引导发展模式;最后,对包括新形象、品牌、独特的城市化等在内的欠发达地区的区域发展战略及若干政策措施进行了探讨。     

Variation in land cover classification due to individual interpreter assessment: a case study of farmland mapping in Norway

Visual interpretations of remote sensing images are required when producing land cover/use maps for management purposes. Human assessment is viewed as an advantage during the interpretation process. However, large mapping projects require several interpreters, and the possibility of inter-operator variability during classification work may affect map usage. In this study, five skilled interpreters from the Norwegian Forest and Landscape Institute independently updated the national Norwegian land resource dataset (AR5) in the same two study areas using the same orthophotos. Cross-tabulations were obtained, and class agreement, overall agreement, kappa agreement and fuzzy Kappa (K_fuzzy) were calculated. Most disagreements occurred in fragmented and complex landscapes, particularly with closely related classes. What can be regarded as an acceptable level of agreement depends on the intended map use and should be based on sensitivity tests exploring the effects of interpreter variation on specific applications of the map product. Finally, the threshold is a political decision based on thorough consideration of the economic and non-economic consequences of the variation tolerated in the maps produced.     

Insolation forcing of Holocene climate change in Southern California: a sediment study from Lake Elsinore

Lake Elsinore is the largest natural lake in Southern California. As such, the lake provides a unique opportunity to investigate terrestrial climate on timescales otherwise underrepresented in the region’s terrestrial environment. In November 2003, three ∼10 m drill cores were extracted from the depocenter region of Lake Elsinore. These drill cores, spanning the past 9,500–11,200 calendar years, represent the first complete Holocene record of terrestrial climate from Southern California. In this paper, we focus on two adjacent, depocenter cores (LEGC03-2 and LEGC03-3), which have been correlated to develop a single composite core. Twenty-two AMS ¹⁴C dates on bulk organic matter and one cross-correlated exotic pollen age constitute the composite core’s age control. Several methods of analysis, including mass magnetic susceptibility, % total organic matter, % total carbonate, % HCl-extractable Al, and total inorganic P are used to infer climate for the past 9,500 calendar years in Southern California. Together, these data indicate a wet early Holocene followed by a long-term drying trend. Recent lake-level reconstructions from Owens Lake and Tulare Lake support our contention for a wetter-than-today early Holocene. Lacustrine sediments from the Mojave Desert also support our conclusions. We suggest that over the duration of the Holocene changing summer/winter insolation alters the region’s long-term hydrologic balance through its modulation of atmospheric circulation and its associated storm tracks. Minimum early Holocene winter insolation and maximum summer insolation act together to increase the region’s total annual precipitation by increasing the frequency of winter storms as well as enhancing the magnitude and spatial extent of the North American monsoon, the frequency of land-falling tropical cyclones in Southern California, and regional convective storms, respectively. Gradual decreases in summer insolation and increases in winter insolation produce the opposite effect with maximum drying in the late Holocene.     

Local communities and the new environmental planning: a case study from Zanzibar

Sub–Saharan Africa is experiencing a new round of conservation initiatives, based around democratized local institutions and local knowledge of the environment. This essay uses political ecology research from a case study settlement in the Zanzibar islands of Tanzania to interrogate how to create the enabling conditions for these new conservation programmes. The case study highlights the importance of understanding social and political issues at the local scale for appreciating the problematic trajectories of progressive environmental planning strategies in Africa in the context of democratization.     

Hydrophytes of the oases in the Sierra de la Giganta of Central Baja California Sur, Mexico: Floristic composition and conservation status

One of the features of the Sierra de la Giganta mountain range is the existence of many small riparian wetlands (oases) along drainage channels. There are no geohydrological studies from which to determine their dynamics in the arid environment, but these areas confront increasing water extraction to satisfy demands of small local settlements. This study compiled a checklist of the hydrophytes from 12 representative oases, and discusses their current status on the basis of composition, richness, and species characteristics. Floristic composition (absence–presence of 57 hydrophytes) at each location was classified by using UPGMA to represent a dendrogram of group cohesivity. Two major kinds of locations are present. By analysing individual site characteristics, we found that one group occurs in places under “good conservation conditions” and the other composed of locations that are “impacted” in several ways. The former group contains oases that are relatively rich in species, including most of the aquatic forms, which are sensitive to disturbance. Geographical affinity of the floristic list reveals that most species have a broad distribution, mostly in tropical America.     

Crustal structure of the Whipple Mountains, southeastern California: a refraction study across a region of large continental extension

Summary. Closely spaced refraction profiling across the Whipple Mountains metamorphic core complex in southeastern California yields a complex picture of crustal structure in this region of large continental extension. A NE-directed profile, parallel to the extension direction, reveals a high-velocity mid-crustal layer (6.6–6.8 km s⁻¹) at 16-18 km depth, bounded above and below by laterally discontinuous low-velocity zones (<6.0 km s⁻¹). In marked contrast, a NW-directed profile shows a more uniform 6.0 km s⁻¹ crust down to the crust-mantle boundary. The apparent contrast between these two perpendicular profiles may be related not only to a more complex geologic structure in the NW-SE direction, but also to velocity anisotropy associated with mid-crustal mylonites. Despite the differences between the two refraction profiles, both define a flat Moho at 26-27 km depth with an associated upper mantle-velocity of 7.8 km s⁻¹. This observation is significant as it suggests that, although the amount of extension has been highly variable regionally, the crust is no thinner beneath the Whipple Mountains (where extension has been extreme) than the surrounding mountain ranges. Such an observation requires either that the crust was considerably thicker prior to extension, or that lateral flow in the lower crust and/or inflation of the crust via magmatism occurred contemporaneous with extension.     

Integrating GIS and data warehousing in a Web environment: A case study of the US 1880 Census

While the business intelligence sector, involving data warehouses and online analytical processing (OLAP) technologies, is experiencing strong growth in the IT marketplace, relatively little attention has been devoted to the problem of utilizing such tools in conjunction with GIS. This study contributes to the development of this research area by examining the issues involved in the design and implementation of an integrated data warehouse and GIS system that delivers analytical OLAP and mapping results in real‐time across the Web. The case study chosen utilizes individual records from the US 1880 population census, which have recently been made available by the North Atlantic Population Project. Although historical datasets of this kind present a number of challenges for data warehousing, the results indicate that the integrated approach adopted offers a much more flexible and powerful analytical methodology for this kind of large social science dataset than has hitherto been available.     

特大城市郊区建设用地效益比较研究——以天津市11个市郊区县为例

对于特大城市郊区建设用地效益的比较研究,有助于判别不同地区之间发展质量差异性,以此为特大城市区域资源的合理分配与预测提供支撑.本文基于"核心-边缘"理论,在既有建设用地效益评价方法的基础上,构建了兼顾同级别地区(市郊区县)与不同级别地区(市郊区县与中心城区)之间的"横向-纵向"效益特征模型.在对市郊区县之间效益相对优势...     

Vegetation inventory and conservation evaluation: a case study from the North York Moors, England

A survey of the vegetation of the North York Moors identified nine vegetation associations, one of which has not been recognized in other British uplands; callunetum vulgaris sub-association juncetosum squarrosi. The vegetation associations occur in a mosaic too detailed for mapping at any practical scale, so seven map classes based largely on terrain patterns were mapped from black-and-white aerial photographs.The map classes provide a suitable basis for assessing the extent to which a system of areas managed specifically for conservation might represent the biota of the North York Moors.     

西北地区农业技术扩散环境的空间分异——以陕、甘、宁县域为例

农业技术扩散环境量化与评价可为农业技术的时空扩散提供有益的参考。本文以陕甘宁3省(区)169个县(区)为研究对象,选取衡量农业技术扩散环境的12个指标,运用主成分分析法计算县域分值并分析其差异,同时运用GeoDa软件提供的Moran's I指数和LISA地图等方法描述其空间特征。分析结果表明:① 影响三省(区)县域农业技术扩散环境的主因子为农业产出效率及文化环境、农业资源禀赋条件和农业投入水平;② 三省(区)县域农业技术扩散环境水平存在显著差异,地理空间上存在集聚性;③“热点”县域集中分布在关中地区、河西走廊和宁夏北部引黄灌溉区,“冷点”县域分布在甘肃中南部地区;④ 西北地区农业技术扩散环境空间分异主要是由于自然条件与社会经济文化的空间差异所致。     

山区土地流转对缓解耕地撂荒的作用

耕地撂荒是目前山区发展较快的一种土地利用变化,耕地流转能否缓解这一过程,促进土地资源有效配置,以避免耕地资源浪费,是一个值得探讨的课题。借助前期研究成果,使用多视角两因素散点分析和单因素相关分析方法,旨在查明山区耕地流转对缓解耕地撂荒的作用,结果表明:1在村级尺度上,样区耕地流转与耕地撂荒间呈现显著负相关关系,流转率高的村庄,撂荒率低,尤其在优等耕作条件的耕地中表现更为突出,说明耕地流转可以减少优等耕作条件的耕地撂荒;2在地块尺度上,优等耕作条件的耕地撂荒率显著低于劣等耕作条件,样区耕地的撂荒主要由Ⅳ等耕作条件的耕地所贡献;3在村级尺度上,样区耕作条件对耕地撂荒率的作用较弱,村样本间耕作条件对撂荒率差异的解释能力不强,优等耕作条件的耕地撂荒仍然存在,说明以耕地流转率代表的土地租赁市场尚不发育;4但是,样区耕地流转率高的村庄,优等耕作条件的耕地撂荒率低,说明耕地撂荒仍然受到土地租赁市场的完善程度所左右,且土地租赁市场在优化耕地资源利用方面的作用已有一定程度的显现;5进一步完善土地租赁的市场化程度,有助于减少或降低耕地撂荒现象的发生,可以避免优等耕作条件的耕地浪费。     

中国水禽的保护生物学研究进展

自1971年《湿地公约》签署以来,水禽的生态与保护问题得到了科研工作者和管理人员前所未有的关注,进而使水禽的保护生物学研究快速发展。依据已有的资料,并结合近几年的研究工作,从保护生物学的角度论述中国水禽的研究进展情况,包括中国水禽的保护种群现状、栖息地研究、目前面临的危胁、保护方式及有关保护的理论、方法等,分析了保护中存在的问题及对策,提出了目前和将来一段时间中国水禽保护生物学的研究趋势。     

Water conservation in the Arab region: a must for survival

The Arab region covers an area over 13 million square kilometers in size, with almost 90% of its area classified as arid or extremely arid with very little precipitation, extremely high evaporation and almost no vegetation cover. The region is classified in many international reports as the poorest region in the world in the context of renewable water resources and critical water scarcity which hinders the socio-economic development of many countries in this region. The rapidly increasing population has reduced the per capita share of renewable water to less than the poverty line of 1,000 m 3 /(capita·a) and, in some Arab countries, to less than the extreme poverty line of 500 m 3 /(capita·a). This has led to over-exploitation of non-renewable groundwater and desalination of salty water in many countries with considerable costs and contamination of many renewable sources. Atmospheric processes responsible for aridity in the Arab region are projected to intensify due to climate change, resulting in an alarming decrease in precipitation and increase in evaporation rates. Many concerned entities in the region consider water security as a key element for food security and ultimately political stability. Hence, various efforts have been exerted to identify key problems and suggested solutions. The Arab Water Ministers Council of the Arab League, as well as Reports of the Arab Forum for the Environment and Development (AFED) and the recommendations of the 13th Regional Meeting of the Arab National Committees of the International Hydrological Programme of UNESCO (IHP), have all made similar recommendations on the need to address the issues of water scarcity in the Arab region which will be further discussed in this paper. However, none of these reports focused on "Water Conservation" as an equally important action for coping with water scarcity in the region. There are many definitions for "Water Conservation" in the scientific literature, including huge water savings from irrigation, industrial use, and domestic use as well as methods and approaches for augmenting water supply through non-conventional practices such as water harvesting and waste water reuse. In this paper, a review is provided for definitions, methods and impacts of water conservation and its role in alleviating water scarcity in the Arab region.