县级土地利用动态变化及驱动力分析——以郑州市中牟县为例

以郑州市中牟县为例,利用土地详查和统计数据等资料,建立土地利用动态变化模型,分析了中牟县1996-2008年土地利用数量、速度、程度、区域差异等变化,揭示中牟县土地利用变化特征.同时,采用主成分分析法得出城镇化进程和收入水平提高是影响中牟县土地利用变化的主要驱动因素.     

彭州市土地利用变化及驱动力分析

依据1992～2003土地利用变更数据，分析彭州市土地利用动态、土地利用程度和土地利用区域差异等变化情况。总结了引起土地利用变化的主要驱动力是地形条件、人口增长、工业化和城镇化、第三产业的发展、交通条件、政策因素等六个方面，并针对目前土地利用中存在的主要问题，提出相应的措施，以期对彭州市社会经济发展提供参考。     

城市化进程中土地利用结构的时序变化及驱动力——以辽宁省为例

根据1995—2008年《辽宁省统计年鉴》及土地利用数据,以人口城市化率反映城市化水平,基于信息熵和均衡度原理,分析了辽宁省城市化过程中土地利用结构的动态变化特征,探讨了土地利用结构信息熵和均衡度动态变化的驱动机制。结果表明,伴随着城市化的不断加快,1995—2008年辽宁省土地利用信息熵、均衡度呈现波动状态,各土地利用类型的面积占土地总面积的比例逐渐趋于均衡。但从总体趋势看,土地利用结构的均质性较差,人口因素、经济因素是影响土地利用结构信息熵和均衡度时空变化的主要驱动因子。     

武安市土地利用结构信息熵时空变化分析

分析土地利用结构时空变化是研究区域土地利用优化配置的重要途径之一.基于信息熵理论,以河北省武安市为例,对1996-2006年的土地利用结构信息熵变化以及2006年各乡(镇)信息熵差异进行研究,同时运用主成分分析法对信息熵变化的驱动力进行分析.结果表明,武安市土地利用结构信息熵持续增长,土地利用结构均衡度较高;2006年各乡镇信息熵差异较大,可划分成3种类型区;经济因素和人口流动因素是信息熵变化主要驱动力.     

土地利用结构和强度变化对碳排放影响分析

基于土地利用视角,分析土地利用结构和强度变化对碳排放的影响作用,为制定碳减排对策提供思路。建立扩展的STIRPAT模型,验证了包括土地利用结构和强度在内的社会经济因素变化对碳排放的影响作用。结果表明:人口总量、人均GDP、国际贸易分工、城市化水平、土地利用强度、土地利用结构等因素对碳排放表现为正向促进作用,每提高(改变)1%水平时,碳排放总量将依次提高0.10%、0.16%、0.12%、0.17%、0.21%、0.15%;能源强度因素表现为负作用,每提高1%水平时,碳排放总量将下降0.05%;土地利用强度、经济发展水平、土地利用结构等因素的变动对碳排放总量影响变动贡献率较大,贡献率大小依次为68.75%、49.73%和19.35%。据此提出,适当调整土地利用结构和改变土地利用强度以减缓碳排放的对策建议。     

2003—2008年兰州市土地利用变化及其驱动因素研究

土地利用变化的驱动力研究是全球变化研究中的一个重点。以甘肃省兰州市为例,在土地变更详查数据及兰州市统计年鉴资料基础上,研究土地利用变化的特点,分析城镇化、工业化过程中的土地利用变化趋势及土地利用变化驱动因子。运用主成分分析法得到兰州市土地利用变化的主要驱动因子为人口增长、经济发展、农业发展、政府政策。根据研究结果提出土地管理措施,为研究区土地的可持续利用提供依据。     

基于信息熵的武汉城市土地利用空间结构变动分析

借助城市土地利用空间结构的信息熵和均衡度概念,揭示了武汉城市在20世纪90年代土地利用结构的空间变化规律,得出土地利用职能类型收缩、城市用地趋向不均衡发展态势的结论.利用主成分与灰色关联相结合的方法找出影响武汉城市土地利用空间结构变动的主要动力因子,它们分别是城市福利和城市社会结构变化推动因子、城市产业结构变化拉动因子和城市建设与改造压力因子,其中后两个因子是驱动城市土地利用空间发生变化的最显著性因子.     

工业化进程中城市土地可持续利用评价——以合肥市为例

工业化始终是影响城市土地可持续利用的一个重要因素。从多方面综合分析了合肥市工业化进程,在概括工业化进程中土地利用变化的基础上,选择20个因素作为参评因子,建立评价指标体系,评判合肥市1996—2005的土地可持续利用综合水平,并进行了定量"障碍度"分析,最后针对主要障碍因素提出土地可持续利用的对策。     

区域土地利用的社会效益及其时空特征研究

土地利用的社会效益是社会经济可持续发展的基础。从用地公平、居民生活质量、社会公平和社会保障等四个方面构建土地利用社会效益评价指标体系，采用AHP法、变异系数法和综合评价模型对湛江市土地利用的社会效益进行了评价，并分析了其时空特征。结果表明，1996-2006年湛江市土地利用的用地公平性较高且变化较小，而居民生活质量、社会公平性和社会保障功能都有不同程度的提高，土地利用的社会效益明显增加；2006年土地利用社会效益以遂溪县最高、徐闻县最低。分析了土地利用社会效益的主要影响因素，并提出了相应的对策措施。     

许昌市土地资源利用结构优化配置研究

土地资源优化配置是城市化进程中面临的主要问题,土地利用结构优化配置是土地利用总体规划的主要内容和基本方法,也是区域经济和社会发展规划的重要依据.在对许昌市土地利用变化分析的基础上,结合当地社会经济发展的需求和有关规划控制指标,借助线性规划模型求解未来许昌市土地利用结构的优化方案,力求提高土地利用的综合效益,实现土地资源永续利用和国民经济持续发展.     

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.     

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.     

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.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

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.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.     

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.     

Sources and Transport of Phosphorus to Rivers in California and Adjacent States,U.S., as Determined by SPARROW Modeling

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.