森林碳汇资源开发潜力定量评价与研究——以黑龙江省为例

森林碳汇资源是开展森林碳汇贸易的基础。森林碳汇潜力的定量评价,将为森林碳汇贸易提供可靠的依据。在对森林碳汇资源开发潜力的定量方法进行深入研究的基础上,以黑龙江省为案例进行潜力评价,明确了黑龙江省具有巨大的森林碳汇增量潜力,提出了进一步发展森林碳汇贸易及构建森林碳汇交易市场的可行性。     

Distribution and bioavailability of ceria nanoparticles in an aquatic ecosystem model

Along with the increasing utilization of engineered nanoparticles, there is a growing concern for the potential environmental and health effects of exposure to these newly designed materials. Understanding the behavior of nanoparticles in the environment is a basic need. The present study aims to investigate the distribution and fate of ceria nanoparticles in an aquatic system model which consists of sediments, water, hornworts, fish and snails, using a radiotracer technique. Concentrations of ceria in the samples at regular time intervals were measured. Ceria nanoparticles were readily removed from the water column and partitioned between different organisms. Both snail and fish have fast absorption and clearance abilities. Hornwort has the highest bioaccumulation factors. At the end of the experiment, sediments accumulated most of the nanoparticles with a recovery of 75.7 ± 27.3% of total ceria nanoparticles, suggesting that sediments are major sinks of ceria nanoparticles.     

外源Cd对不同利用方式红壤脲酶活性的影响

采用室内培养实验,通过将外源Cd添加到同一母质、全镉含量相近的不同利用方式的红壤中(林地、水稻土和菜园土),研究了外源Cd污染对不同利用方式红壤脲酶活性的影响。结果表明:整个培养过程中,Cd污染对3种红壤脲酶活性都有抑制作用,且随重金属浓度的增强而增强。同剂量Cd污染对3种红壤脲酶活性的抑制效应不同,大小为林地>水稻土>菜园土。实验设定的Cd处理水平下,对林地、水稻土和菜园土脲酶活性产生显著抑制作用(p<0.05)的Cd浓度分别为5、30和50 mg/kg土。     

CVM研究中支付意愿问卷“内容依赖性”的实证研究——以上海城市内河生态恢复CVM评估为例

为检验意愿价值评估法(Contingent Valuation Method,CVM)中争论的焦点问题——支付意愿的问卷"内容依赖性",本文以上海城市内河生态修复为评估对象,构建CVM的假想市场,设计评估顺序、评估对象尺度、嵌套物品等四重方案,通过720份问卷平行调查对同一评估对象在不同问卷中获得的支付意愿,并进行估计值比较和t检验。研究结果显示:支付意愿的数值随评估尺度的增加并不显著增加;单独评估比作为嵌套物品评估具有更高的支付意愿值;在问卷中先被评估的物品居民给出的支付意愿较高;整体物品的支付意愿小于各部分的加总。研究结果验证了国外实证研究文献报道的"范围不敏感"、"嵌入效应"、"顺序效应"、"部分—整体效应"等现象的存在。对此现象的解释主要是收入效应和替代效应。因此,在将CVM研究结果应用于公共政策中应充分考虑上述因素引起的偏差。     

Stewardship among lifestyle oriented rural landowners

Changes in landownership associated with amenity migration are affecting the demographic, cadastral and ecological conditions of rural landscapes. These changes and concerns about their impacts on natural resource management, including ecological conservation, relate to both the structural consequences of landownership change, land subdivision and to the motivations, management ability and attitudes of lifestyle oriented rural landowners. Based on an Australian case study near Sydney, NSW, this paper examines the motivations and practices of such landowners, assesses potential consequences for vegetation and characterises the landowners according to three stewardship types.     

Monitoring Regional Riparian Forest Cover Change Using Stratified Sampling and Multiresolution Imagery1

Claggett, Peter R., Judy A. Okay, and Stephen V. Stehman, 2010. Monitoring Regional Riparian Forest Cover Change Using Stratified Sampling and Multiresolution Imagery. Journal of the American Water Resources Association (JAWRA) 46(2):334-343. DOI: 10.1111/j.1752-1688.2010.00424.x Abstract: The Chesapeake Bay watershed encompasses 165,760 km² of land area with 464,098 km of rivers and streams. As part of the Chesapeake Bay restoration effort, state and federal partners have committed to restoring 26,000 miles (41,843 km) of riparian forest buffers. Monitoring trends in riparian forest buffers over large areas is necessary to evaluate the efficacy of these restoration efforts. A sampling approach for estimating change in riparian forest cover from 1993/1994 to 2005 was developed and implemented in Anne Arundel County, Maryland, to exemplify a method that could be applied throughout the Bay watershed. All stream reaches in the county were stratified using forest cover change derived from Landsat imagery. A stratified random sample of 219 reaches was selected and forest cover change within the riparian buffer of each sampled reach was interpreted from high-resolution aerial photography. The estimated footprint of gross change in riparian forest cover (i.e., the sum of gross gain and gross loss) for the county was 1.83% (SE = 0.22%). Stratified sampling taking advantage of a priori knowledge of locations of change proved to be a practical and efficient protocol for estimating riparian forest buffer change at the county scale and the protocol would readily extend to much broader scale monitoring.     

Ecologically Functional Floodplains: Connectivity,Flow Regime,and Scale1

Opperman, Jeffrey J., Ryan Luster, Bruce A. McKenney, Michael Roberts, and Amanda Wrona Meadows, 2010. Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale. Journal of the American Water Resources Association (JAWRA) 46(2):211-226. DOI: 10.1111/j.1752-1688.2010.00426.x Abstract: This paper proposes a conceptual model that captures key attributes of ecologically functional floodplains, encompassing three basic elements: (1) hydrologic connectivity between the river and the floodplain, (2) a variable hydrograph that reflects seasonal precipitation patterns and retains a range of both high and low flow events, and (3) sufficient spatial scale to encompass dynamic processes and for floodplain benefits to accrue to a meaningful level. Although floodplains support high levels of biodiversity and some of the most productive ecosystems on Earth, they are also among the most converted and threatened ecosystems and therefore have recently become the focus of conservation and restoration programs across the United States and globally. These efforts seek to conserve or restore complex, highly variable ecosystems and often must simultaneously address both land and water management. Thus, such efforts must overcome considerable scientific, technical, and socioeconomic challenges. In addition to proposing a scientific conceptual model, this paper also includes three case studies that illustrate methods for addressing these technical and socioeconomic challenges within projects that seek to promote ecologically functional floodplains through river-floodplain reconnection and/or restoration of key components of hydrological variability.     

Effects of Groundwater-Flow Paths On Nitrate Concentrations Across Two Riparian Forest Corridors1

Speiran, Gary K., 2010. Effects of Groundwater-Flow Paths on Nitrate Concentrations Across Two Riparian Forest Corridors. Journal of the American Water Resources Association (JAWRA) 46(2):246-260. DOI: 10.1111/j.1752-1688.2010.00427.x Abstract: Groundwater levels, apparent age, and chemistry from field sites and groundwater-flow modeling of hypothetical aquifers collectively indicate that groundwater-flow paths contribute to differences in nitrate concentrations across riparian corridors. At sites in Virginia (one coastal and one Piedmont), lowland forested wetlands separate upland fields from nearby surface waters (an estuary and a stream). At the coastal site, nitrate concentrations near the water table decreased from more than 10 mg/l beneath fields to 2 mg/l beneath a riparian forest buffer because recharge through the buffer forced water with concentrations greater than 5 mg/l to flow deeper beneath the buffer. Diurnal changes in groundwater levels up to 0.25 meters at the coastal site reflect flow from the water table into unsaturated soil where roots remove water and nitrate dissolved in it. Decreases in aquifer thickness caused by declines in the water table and decreases in horizontal hydraulic gradients from the uplands to the wetlands indicate that more than 95% of the groundwater discharged to the wetlands. Such discharge through organic soil can reduce nitrate concentrations by denitrification. Model simulations are consistent with field results, showing downward flow approaching toe slopes and surface waters to which groundwater discharges. These effects show the importance of buffer placement over use of fixed-width, streamside buffers to control nitrate concentrations.     

人工湿地系统微生物去除污染物的研究进展

人工湿地污水处理系统具有净化效果显著、建设和运行费用低廉、管理简便等优点,近年来越来越受到人们的重视。人工湿地是利用介质、植物和微生物构成的复合系统来处理污水。微生物在人工湿地系统净化污水过程中发挥着重要作用。介绍了人工湿地系统中微生物去除污染物的研究进展,重点讨论了人工湿地对污染物和特殊有机污染物的去除以及系统基质中微生物的种群和活性等内容,并结合我国研究现状展望了该领域的研究前景。人工湿地系统微生物对污染物去除将成为人工湿地生态系统服务功能评价、人工湿地生态系统健康与稳定的诊断的重要组成部分。     

基于复合生态系统理论的长沙湘江滨水区景观资源评价与优化

近年来,随着我国经济的飞速发展、社会经济的转型,以及人们环境意识的提高,滨水区开发已成为我国城市开发建设的热点。城市滨水区景观规划设计研究对于合理、充分利用城市滨水区景观资源,塑造特色鲜明的城市形象,提高城市生态环境质量,促进城市滨水区开发有着重要意义。从复合生态系统理论的角度,在湘江滨水区景观资源调查、景观资源分类的基础上,运用灰色聚类法对湘江滨水区景观资源进行定量评价,提出景观资源优化思路,探讨滨水区景观规划设计的途径。认为现代城市大规模滨水区更新改造和开发大背景下的城市滨水区景观规划设计,应尊重城市地域性特点、文化内涵和风土人情,并与传统的滨水活动有机结合,保护和突出城市历史格局和风貌特色。