The Potential Influence of Seasonal Climate Variables on the Net Primary Production of Forests in Eastern China

Knowledge of the effects of climate factors on net primary production (NPP) is pivotal to understanding ecosystem processes in the terrestrial carbon cycle. Our goal was to evaluate four different categories of effects (physical, climatic, NDVI, and all effects[global]) as predictors of forest NPP in eastern China. We developed regression models with data from 221 NPP in eastern China and identified the best model with each of the four categories of effects. Models explained a large part of the variability in NPP, ranging from 46.8% in global model to 36.5% in NDVI model. In the most supported global model, winter temperature and sunshine duration negatively affected NPP, while winter precipitation positively affected NPP. Thus, winter climate conditions play an important role in modulating forest NPP of eastern China. Spring temperature had a positive affect on NPP, which was likely because a favorable warm climate in the early growing season promotes forest growth. Forest NPP was also negatively affected by summer and autumn temperatures, possibly because these are related to temperature induced drought stress. In the NDVI model, forest NPP was affected by NDVI in spring (positive), summer (negative) and winter (negative) seasons. Our study provides insight into seasonal effects of climate and NPP of forest in China, as well as useful knowledge for the development of climate-vegetation models.     

城镇化可持续发展评价指标体系初步探讨

基于可持续发展理念,探讨了城镇化的涵义、发展水平的评价方法.结合一系列指导思想和原则,构建了一个涉及经济发展、人口发展、生活质量、设施环境四个方面的城镇化可持续发展评价指标体系.以山东省为例,选取了2003年东部沿海地区5个省市相关数据资料,运用横向比较的方法,对山东省城镇化可持续发展水平进行了分析.     

中国大陆城市化水平的省际差异及分类研究

旨在研究中国大陆城市化水平的省际差异及其分类。通过对2008年中国大陆31个省(市、自治区)城市化水平的因子分析、聚类分析及内部协调性分析,结果表明大陆地区的城市化发展水平呈现东高西低态势,城市发展走向集群化,城市化发展水平高的省份其内部协调性也高。由分析可知,城市化发展的省际差异是由区位、经济拉动和政策导向3个主要因素影响而成的,进而提出协调发展的对策。     

Identifying Riparian Buffer Effects on Stream Nitrogen in Southeastern Coastal Plain Watersheds

Within the Southeastern (SE) Coastal Plain of the U.S., numerous freshwaters and estuaries experience eutrophication with significant nutrient contributions by agricultural non-point sources (NPS). Riparian buffers are often used to reduce agricultural NPS yet the effect of buffers in the watershed is difficult to quantify. Using corrected Akaike information criterion (AIC_c) and model averaging, we compared flow-path riparian buffer models with land use/land cover (LULC) models in 24 watersheds from the SE Coastal Plain to determine the ability of riparian buffers to reduce or mitigate stream total nitrogen concentrations (TNC). Additional models considered the relative importance of headwaters and artificial agricultural drainage in the Coastal Plain. A buffer model which included cropland and non-buffered cropland best explained stream TNC (R ² = 0.75) and was five times more likely to be the correct model than the LULC model. The model average predicted that current buffers removed 52 % of nitrogen from the edge-of-field and 45 % of potential nitrogen from the average SE Coastal Plain watershed. On average, 26 % of stream nitrogen leaked through buffered cropland. Our study suggests that stream TNC could potentially be reduced by 34 % if buffers were adequately restored on all cropland. Such estimates provide realistic expectations of nitrogen removal via buffers to watershed managers as they attempt to meet water quality goals. In addition, model comparisons of AIC_c values indicated that non-headwater buffers may contribute little to stream TNC. Model comparisons also indicated that artificial drainage should be considered when accessing buffers and stream nitrogen.     

基于泰尔指数的我国碳生产率区域差异性分析

在应对全球气候变暖的背景下,中国的碳排放及其变化趋势成为世界各国关注的焦点.我国如何在保持经济高速增长的同时,抑制CO2排放增速、提高碳生产率是关键,而这需要依赖于省区层面的减排行动,从区域层面研究碳生产率问题具有重要现实意义.测算了东、中、西部地区域碳生产率的泰尔指数,并对总差异进行了分解,提出了对策建议.     

江苏环境资源与第一性生产潜力的估算

本文采用Y=F(Q)·F(R)·F(Y)·F(W)·F(S)及其分部公式,计算了江苏省主要农作物、森林和水生植被的潜在生产力。计算表明,麦类的潜力为2.14×10~3～6.08×10~3kJ/m~2·a,水稻的潜力为4.38×10~3～14.2×10~3kJ/m~2·a,春玉米的潜力为8.46×10～20.51×10~3kJ/m~2·a,森林植被为14.5×10~3～54.2×10~3kJ/m~2·a,水生植被为2.67×10~3～5.77×10~3kJ/m~2·a。     

浅谈我国的网络立法

互联网正在极大地改变人们的生活方式、生产方式及行为模式,要确保一个安全健康的网络环境为我们服务,需要从立法上加以保证。本文从我国网络立法的现状,存在的问题及立法时应注意的问题几个方面对我国的网络立法进行了探讨。     

基于LMDI分解法的我国碳生产率影响因素研究

运用LMDI分解法,以1995-2010年为样本期,按东、中、西三大区域把我国碳生产率总体变动分解为能源效率、碳排放能耗和碳排放结构3个影响因素,得出以下主要结论:1995-2010年我国碳生产率变化除了2003-2005年为负数外,其余期间均为正数,表明我国碳生产率在逐年提高.碳生产率总体变动因素分解的贡献值和贡献率表明,能源效率因素是影响我国碳生产率变动的主要因素,贡献值为0.9722,贡献率为87.66％,其变动趋势决定了碳生产率的变动趋势;单位碳排放能耗因素贡献值为0.1431,贡献率仅为12.9％,影响较小;而碳排放结构因素的贡献值和贡献率分别为-0.0063和-0.56％,表明碳排放结构抑制了碳生产率的增加.因此,提高区域能源效率,改善区域碳排放结构,对提高我国碳生产率具有重要意义.     

农村城镇化进程中的环境问题及对策

在简单阐述农村城镇化的概念及意义的基础上,分析了城镇化进程中生活污染问题、土壤问题和工业污染问题,提出通过提高群众的环保意识等措施,解决农村城镇化进程中的环境问题。     

Effects of Increasing Urbanization on the Ecological Integrity of Open Space Preserves

This article analyzes the effects of increasing urbanization on open space preserves within the metropolitan area of Phoenix, Arizona, USA. Time series analysis is used in 10-year increments over 40 years to study urban landscape change. Three landscape metrics—(1) matrix utility (measures intensity of adjacent land uses), (2) isolation (measures distances to other open space patches), and (3) connectivity (measures physical links to other open space patches and corridors)—are used to assess changes in landscape patterns and serve as indicators of urban ecological integrity of the open space preserves. Results show that in the case of both open space preserves, general decline in indicators of urban ecological integrity was evident. The matrix utility analysis demonstrated that increasing intensity of land uses adjacent to preserve is likely to increase edge effects, reducing the habitat value of interior or core habitat areas. Isolation analysis showed that both preserves have experienced increasing isolation from other open space elements over time. Also, connectivity analysis indicated that terrestrial connections to other open space elements have also deteriorated. Conclusions of this research demonstrate that while preservation of natural areas as open space is important in an urban context, intense development of surrounding areas reduces the urban ecological integrity significantly.     

2000—2014年中国经济系统物质流核算与资源产出率研究

本文利用经济系统物质流分析框架核算了我国2000—2014年的主要物质流、资源产出率等指标。结果表明：① 2000—2014年本地采掘物质量、进口量和本地处置后排放均有较快增长。2011—2014年本地采掘中生物质采掘量逐年稳步增长,非金属矿石和化石燃料采掘量处于下降趋势。本地处置后排放中空气排放物贡献了绝大部分比例并逐年增长,水污染排放物逐年下降。② 2000—2014年人均资源的采掘、投入和消耗量均有大幅增长,2014年人均物质消耗量比2000年增长1倍以上。资源产出率和单位GDP本地采掘、投入物质量处于波动式增长趋势,本地采掘每吨物质所贡献的GDP已连续三年超过资源产出率。③ 2014年中国资源产出率约为欧盟28国平均水平的1/4。2010年我国省级资源产出率差异较大,小部分地区已超过欧盟同期水平,但仍有大部分地区的资源产出率较低,未达到全国平均水平。     

我国欠发达地区城市化研究进展及前瞻

在分析欠发达地区城市化影响因素、发展战略、模式及动力机制的基础上，认为我国现阶段关于欠发达地区城市化的研究主要有两点不足：一是缺乏对以人的素质作为城市化推动力的研究；二是在研究空间结构上缺乏对行政区交界处落后地区城市化的研究。为此，关注对人的研究、扩大空间范围应是今后研究的方向。     

华东地区碳源、碳汇和碳生产力研究

从碳源、碳汇和碳生产力的角度深入研究了华东地区6省1市2005-2011年之间低碳经济发展现状,采用变异系数和空间自相关等分析方法对该地区碳源、碳汇和碳生产力差异大小及其空间聚集特性进行了分析,以期为分析华东地区乃至全国低碳经济发展现状和趋势提供借鉴.     

城市化及其对大气环境的影响

中国城市化的快速发展与能源消耗的迅速增加,给中国城市带来了众多大气环境问题。城市化不仅造成了如热岛效应等城市周边气候的变化,还带来了酸雨频发、空气颗粒物污染加重和汽车尾气污染严重等城市环境问题。对此,应当从科学编制城市发展规划,合理调整经济结构,加强环境管理与污染治理,增加城市绿化面积等方面入手,改善城市大气环境。     

Effects of Grazing Pressure on Succession Process and Productivity of Old Fields on Mediterranean Islands

Poterium spinosum, competitive under conditions of overgrazing and fire, accounted for 70%–85% of the total plant cover in all sites, except Santorini, where participation of spiny species was very low. In the recently abandoned sites, annuals accounted for 50%–60% of the standing biomass, but constituted only a tiny fraction in those abandoned for 30 years or more. This was not paralleled by any remarkable increase of the total plant cover. In fact, the yearly produced green biomass decreased with the years after abandonment. The productivity of old fields abandoned for a long time is insufficient to support the grazing animals present. This shortfall, given the animals' requirements, is most dramatic in Symi. The nonrecovering vegetation in the old fields of these mountainous islands constitutes a severe environmental threat; remedial measures appear imperative.     

2003-2012年中国城市化效率与生态效率的动态耦合研究

通过构建城市化效率和生态效率的指标体系,利用DEA模型、相对发展度模型和耦合度模型分析了2003-2012年中国30个省的城市化效率与生态效率相对发展水平和耦合水平.结果表明：①10年间耦合度整体上呈现平缓下降—缓慢上升的趋势,耦合水平较高;②中国城市化效率与生态效率耦合度的空间分布格局发生明显变化,三级梯度的分布空间规律逐渐被打破,呈现出交错分布的格局;③在城市化不断推进的过程中,由于经济水平、产业结构、生态环境等方面存在差异,各省份需要合理地平衡城市化效率与生态效率的发展,确保城市建设和生态建设地有序进行.     

源远流长的中国古代可持续发展思想——兼谈对我国城市化发展的启示

本文简述了中国传统文化尤其是古代哲学中有关可持续发展的朴素思想和治国主张，并指出其共同构成了人类可持续发展思想与战略的理论体系。同时，简要说明了中国古代可持续发展思想对推进我国区域可持续发展尤其是城市化进程的三方面重要启示。     

Effects of Climate and Land Cover on Hydrology in the Southeastern U.S.: Potential Impacts on Watershed Planning

The hydrologic response to statistically downscaled general circulation model simulations of daily surface climate and land cover through 2099 was assessed for the Apalachicola‐Chattahoochee‐Flint River Basin located in the southeastern United States. Projections of climate, urbanization, vegetation, and surface‐depression storage capacity were used as inputs to the Precipitation‐Runoff Modeling System to simulate projected impacts on hydrologic response. Surface runoff substantially increased when land cover change was applied. However, once the surface depression storage was added to mitigate the land cover change and increases of surface runoff (due to urbanization), the groundwater flow component then increased. For hydrologic studies that include projections of land cover change (urbanization in particular), any analysis of runoff beyond the change in total runoff should include effects of stormwater management practices as these features affect flow timing and magnitude and may be useful in mitigating land cover change impacts on streamflow. Potential changes in water availability and how biota may respond to changes in flow regime in response to climate and land cover change may prove challenging for managers attempting to balance the needs of future development and the environment. However, these models are still useful for assessing the relative impacts of climate and land cover change and for evaluating tradeoffs when managing to mitigate different stressors.     

政府推动型城镇化对企业污染排放的影响研究

现阶段,资源过度消耗与环境恶化成为中国经济与社会可持续发展的障碍。虽然现有研究从多方面探究了环境污染的治理机制,但对政府推动型城镇化这一重要的宏观政策的关注不足。本文以中国工业企业为研究样本,利用撤县设区改革的准自然实验构建双重差分模型,考察政府推动型城镇化对企业污染排放的影响。实证结果显示,撤县设区改革显著地减少了原县辖区内企业的污染排放量,即政府推动型城镇化对企业污染排放具有“治理效应”。异质性分析发现,撤县设区改革对企业污染排放的“治理效应”来源于主动推动型撤县设区而非被动实施型撤县设区;相比于在非重污染行业的企业以及隶属于县级以上的企业中,撤县设区改革对企业污染排放的“治理效应”在重污染行业的企业以及隶属于县级以下的企业中更强。影响机制分析发现,撤县设区改革后,原县级政府的财政收入显著下降、基础建设性财政支出显著减少而民生性财政支出显著增加,说明撤县设区后,原县级政府财政收入的经济激励弱化,财政支出目标亦从基础设施建设转变为提供公共服务,从而有助于治理企业污染排放问题。