Climate voting in the US Congress: the power of public concern

In the United States, few constituents know and understand climate policy, prioritize it as a political topic, or let their voting decisions depend on it. In these conditions, representatives would not be expected to pay heed to constituents’ climate concern in their voting decisions. Still, even after controlling for the presence of interest groups, campaign finance, and legislators’ party affiliation and ideology, there is a consistent link between public opinion and votes on cap-and-trade legislation in the House (and to a lesser degree in the Senate). The same is true when public opinion is simulated based on pre-vote district characteristics. Explanations for these findings are discussed.     

企业环境寻求、污染密集型生产区际转移与环境监管

在当前强调产业结构调整的政策背景下,产业有序转移必须以有利于或者加强环境保护为基本目标。环境规制差异造成了不同经济地域之间污染密集型生产的比较优势调整,强化了高污染产业进行生产区位选择的动机,以规避来自政府的环境监管。环境治理成本的不同是高污染企业区际转移的重要驱动因素,企业环境寻求策略推动了污染密集型生产由环境规制强度高的地区向环境规制松弛地区的转移。企业污染密集型生产的区际转移受到环境要素产品生产比较优势的明显影响,这些环境要素产品与区际环境规制差异、企业市场内部化战略以及污染密集型产品的生命周期密切关联。借鉴一般均衡分析框架,可以明晰企业环境寻求策略下污染密集型生产转移的内在机制。一方面,环境成本差异决定了非环境友好产品生产转移的意愿,高强度的环境规制使得企业生产的边际环境治理成本和平均环境治理成本提高,污染密集型生产外迁的动力加强,生产效率高的企业对环境规制强度更加敏感。污染密集型生产承接地提高环境规制强度能形成对环境负面影响的有力对冲,遏制环境恶化趋势。另一方面,合理的区际环境政策差异能在产业有序转移中发挥重要作用。合理设定区际环境规制级差与碳信征信系统建设,加强分类监管与行业节能减排,建立拟承接生产项目的效率筛选机制,提高区域市场开放程度、降低产业优惠政策所形成隐性市场保护等环境监管手段是保证欠发达地区通过产业承接实现跨越式发展的关键所在。     

川南山地林分变化对土壤物理性质和抗蚀性的影响

以川南天然林(TRL)及其转变成的毛竹林(MZL)、檫木林(CML)、柳杉林(LSL)、杉木林(SML)和水杉林(SSL)为对象,研究不同林分土壤物理性质和抗蚀性差异,以主成分分析法(ZCFM)和隶属函数法(LSHM)分别计算的土壤抗蚀性综合值Ⅰ(KSX-Ⅰ)和Ⅱ(KSX-Ⅱ)评价林分变化对土壤抗蚀性的影响,探索简便易行的土壤抗蚀性综合评价方法。结果表明,天然林转变为人工林后土壤物理性质和抗蚀性变差,呈现出有机质和0.25 mm水稳性团聚体含量、水稳性团聚体平均重量直径、团聚度、孔隙度及物理稳定性指数降低,而结构体破坏率、不稳定团粒指数、容重、分散率及侵蚀系数增加。各林分土壤KSX-Ⅰ和KSX-Ⅱ均呈现出TRLCMLSSLLSLMZLSML的规律变化。土壤抗蚀性指标间相关性均达到显著(p0.05)水平;土壤KSX-Ⅰ和KSX-Ⅱ之间呈显著相关关系(p0.05),且两者均与各抗蚀性指标间呈显著相关(p0.05)。说明天然林植被变化后会使土壤抗蚀性降低,影响原有植被水土保持功能,应该加强天然林及其生态功能保护;ZCFM和LSHM均可作为计算土壤抗蚀性综合值的有效方法,但考虑到计算过程的难易度,后者更简便易行。结果为土壤抗蚀性综合评价新方法的建立提供了参考。     

基于安徽省土地利用变化的地形梯度效应分析

为揭示地形因素与土地利用空间格局演变的关系,以安徽省2000年、2005年以及2010年Landsat TM影像和DEM数据为数据源,利用坡向、地形起伏度、坡度变率和地形位指数多种地形因子,并结合地学信息图谱分析理论从综合角度系统研究土地利用结构时空分异格局在地形梯度上的变化特点及其规律。结果表明:1)研究区主要的土地利用类型是耕地和林地,其次是建设用地和未利用土地,且建设用地面积逐期增加趋势显著。2)2000~2010年研究区不同土地利用类型在不同地形梯度区间的分异规律存在明显差异。低地形梯度范围是耕地、水域和建设用地的优势分布区;中地形梯度范围是草地的集中分布区;林地的优势分布区集中在高地形梯度范围。3)2000~2010年研究区土地利用图谱以稳定型和后期变化型为主,低地形梯度和高地形梯度是稳定型图谱的集中分布区,中低、中高和高地形梯度范围是后期变化型图谱的优势分布区。2000~2005年林地的优势分布区有向较低地形位梯度扩张的趋势,其中,耕地是主要的转入来源。2005~2010年耕地的优势分布区有向较高地形位梯度扩张的趋势,变化模式主要为:"林地–耕地"、"未利用地–耕地"和"草地–耕地"。     

湖北郧西县庹家湾剖面粒度组成特征及其环境意义

对湖北省郧西县庹家湾(TJW)剖面的地层序列、年代、磁化率及粒度组成进行研究。结果表明:TJW剖面具有表土(MS)→全新世黄土(L0)→古土壤(S0)→过渡层(Lt)→马兰黄土(L1)→黄土与砂互层(T1-al2)→砾石层(T1-al1)的地层序列;在马兰黄土层上部的黏粒含量、黏粒/粉砂值以及磁化率值明显高于典型马兰黄土,而接近古土壤(S0),其成壤作用明显,属于较典型的弱古土壤层(L1-S1和L1-S2),其年龄在27.3~21.6 ka B.P.之间。此现象反映了在汉江上游地区,晚更新世时期的冰期气候并不是持续稳定的,在27.3~21.6 ka B.P.期间存在相对短暂的温暖湿润阶段,这次气候事件可与黄土高原地区进行良好对比。     

近50年鄱阳湖五大流域降水变化特征研究

基于鄱阳湖流域在江西省内部分对应的79县市气象站1960～2006年逐日降水观测资料,采用线性回归的方法分别研究五大流域的年降水量、降水日数、暴雨日数等3要素的变化趋势,并用Mann法进行了变化趋势的显著性检验,用距平与均方差之比达到15和20作为气候异常检验指标,对各流域的各时间序列进行了异常检验,采用了Mann Kendall法对各时间序列进行突变检测。结果表明：（1）各流域的年降水量变化趋势基本一致,年降水量与年暴雨日数密切相关;饶河流域强降水事件较多,降水强度大,赣江中游流域降水时间分布相对较均匀,强降水事件较少;（2）各流域年降水量、暴雨日数总体呈波动上升趋势,20世纪90年代以来暴雨日数异常偏多的概率最大;（3）年降水日数以20世纪80年代中期为界,之前呈波动上升趋势,之后呈波动下降趋势,2002年至今各流域降雨日数明显偏少;（4）各流域的年降水量、降水日数、暴雨日数均未出现趋势性的突变;（5）近50年来鄱阳湖流域降水时间分布不均的情况加剧,旱涝灾害风险增加。     

经济快速发展地区土地利用结构的时空演变——以苏锡常地区为例

利用1996～2007年苏锡常地区土地利用变更数据,从土地利用变化幅度、动态度、变化强度、相对变化率及景观生态学角度,对区域土地利用结构的动态变化及区域差异进行分析。研究结果表明：近十多年来,由于区域经济快速发展,工业用地扩展迅猛,城镇加速蔓延,从而导致区内耕地面积锐减,居民点及工矿用地、交通用地所占比例则逐年上升,交通用地的变化幅度及动态度最大;各用地类型的变化强度在此期间呈一定波动,除牧草地外,交通用地历年的变化强度之和最大,其次为园地、居民点及工矿用地、水利设施用地、耕地、其他农用地、林地、未利用地;区域土地利用结构逐渐向均衡状态发展,用地结构的均质性逐渐增强,地区土地利用结构渐趋稳定;各市耕地、居民点及工矿用地、其他农用地的变化幅度及相对变化率差别不大,而园地、林地、牧草地、交通用地、水利设施用地及未利用地的变化幅度及相对变化率区域差异较大,且三市园地、牧草地及未利用地的变化方向不一致。     

Species-specific and context-dependant disruption of temporal population fluctuations resulting from hypereutrophication events

This study quantifies the disruption of zooplankton population fluctuations in relation to two magnitudes of fire retardant contamination events using artificial ponds as model systems. Population time series were analysed using redundancy analysis where time was modelled with a principal coordinate of neighborhood matrices approach that identified relevant scales of fluctuation frequencies. Analyses of temporal coherence provided insight whether population fluctuations correlated with system intrinsic or extrinsic forces. Responses to stress were species-specific and context-dependant. Contamination changed temporal structure in some species. These alterations were associated with an increased intrinsic control of dynamics. In some cases the magnitude of impact was unrelated to contamination severity. Some populations were less tolerant of pollution in the low relative to the high concentration treatment. Results suggest that population-level monitoring of degraded sites may be suboptimal because disparate population responses complicate the selection of specific sentinel organisms to monitor stress.     

Predicting land cover using GIS, Bayesian and evolutionary algorithm methods

Modelling land cover change from existing land cover maps is a vital requirement for anyone wishing to understand how the landscape may change in the future. In order to test any land cover change model, existing data must be used. However, often it is not known which data should be applied to the problem, or whether relationships exist within and between complex datasets. Here we have developed and tested a model that applied evolutionary processes to Bayesian networks. The model was developed and tested on a dataset containing land cover information and environmental data, in order to show that decisions about which datasets should be used could be made automatically. Bayesian networks are amenable to evolutionary methods as they can be easily described using a binary string to which crossover and mutation operations can be applied. The method, developed to allow comparison with standard Bayesian network development software, was proved capable of carrying out a rapid and effective search of the space of possible networks in order to find an optimal or near-optimal solution for the selection of datasets that have causal links with one another. Comparison of land cover mapping in the North-East of Scotland was made with a commercial Bayesian software package, with the evolutionary method being shown to provide greater flexibility in its ability to adapt to incorporate/utilise available evidence/knowledge and develop effective and accurate network structures, at the cost of requiring additional computer programming skills. The dataset used to develop the models included GIS-based data taken from the Land Cover for Scotland 1988 (LCS88), Land Capability for Forestry (LCF), Land Capability for Agriculture (LCA), the soil map of Scotland and additional climatic variables.     

Wood bison population recovery and forage availability in northwestern Canada

Forage availability was assessed to determine sustainable stocking rates for eight broadly defined vegetation types (Treed Uplands, Treed Lowlands, Mixed Tall Shrub/Sedge, Closed-canopied Willow, and Open-canopied Willow, Meadow, Wetland Grass, Wetland Sedge) for use by wood bison (Bison bison athabascae), a threatened subspecies, in the Canadian boreal forest of northern Alberta. Clip plots (n=108) were used to sample peak availability of herbs and current annual growth of Salix spp. in late summer. Graminoid wetlands dominated by Carex atherodes, Carex aquatilis, Carex utriculata, Scolochloa festucacea, or Calamagrostis stricta produced 1975-4575 kg ha(-1) of fair to good quality forage, whereas treed stands produced < 250 kg ha(-1) of forb-dominated forage (>85% content), which was below a published 25% foraging efficiency threshold of 263 kg ha(-1) for bison. Upland forests that dominate the region produced < or = 1 animal unit day (AUD) of forage per hectare in summer. Most forest understory plants were of poor forage value, suggesting the potential sustainable stocking rate of such areas was actually < or = 0.3 AUD ha(-1), with even lower rates during winter due to snow cover. Herbaceous wetlands contained approximately 78 AUD ha(-1) of forage, but were considered largely unavailable in summer because of flooding and soft organic soils that make access difficult. Conversion of prime foraging habitat to agricultural land, forest expansion due to fire control, and a warmer and wetter climatic regime after the mid-1900s likely contributed to a regional reduction in carrying capacity. It is hypothesized that substantial recovery of the wood bison population toward historical levels will be constrained in northern Alberta by the availability of summer forage, and the limited extent of graminoid wetlands that provide winter foraging habitat.