基于系统动力学模型的区域可持续发展分析

结合系统动力学建模的原则和方法,构建了区域可持续发展系统动力学模型。根据区域社会经济发展和环境变化的动态性,子系统之间能量和物质流通的转化与信息的交互,形成人口、科技、环境、资源、经济5个子系统。某农业县三种方案对比的模拟实验表明,控制人口,大力发展生态农业和第三产业,优化产业发展结构,不但实现了GDP增长,而且环境质量指数稳步提升,促进了区域经济社会与环境的可持续发展。     

丙溴磷在稻田环境中的残留动态研究

确立了气相色谱法测定丙溴磷残留量的检测方法.采用该方法,丙溴磷在土壤、植株、糙米、稻壳和田水中的平均添加回收率为87.2％～103.6％,变异系数为3.20％～11.50％,最低检测质量浓度:田水为0.005 mg/kg;土壤、植株、糙米和稻壳为0.050 mg/kg.残留动态研究表明,丙溴磷在田水、植株和土壤中的半衰...     

近年来江苏省海岸带土地利用/覆被变化时空动态研究

海岸带是陆海生态系统交错带,具有重要的经济与生态价值,其生态环境具有脆弱性特征。海岸带的开发利用使其地区生态环境发生变化,而土地利用/覆被变化是地区生态环境变化的重要组成部分和主要原因之一。取1980、2000、2005、2008年4个时相的TM遥感影像为数据源,通过土地利用结构、土地利用多样性以及土地利用程度指数分析江苏省1980年以来海岸带土地利用/覆被变化的时空动态特征,揭示地域差异与梯度分异特征。研究结果表明：（1）江苏省海岸带土地利用结构表现为生态用地占比高,城镇与农村居民点占比低的特征。1980年以来,不同土地利用类型数量不断变化而结构相对稳定;类型趋于多样化且利用强度增加。（2）江苏省海岸带土地利用存在地域差异特征。土地利用结构存在不同模式且变化相对稳定;土地利用程度在南北方向上存在高 低 高分布特征,但逐步被打破。（3）江苏省海岸带土地利用在陆海方向上存在梯度特征。土地利用多样性陆海方向呈现低 高 低模式,土地利用强度陆海方向呈现高 中 低模式。土地利用多样性高值区逐步向海岸带中部移动;海岸带各缓冲区土地利用程度分异逐步增大。以射阳河口作为分界点,南北地区梯度规律存在差异性     

Fate of atrazine in a soil under different agronomic management practices

Agricultural management affects the movement of atrazine in soil and leaching to groundwater. The objective of this study was to determine atrazine adsorption in a soil after 20 years of atrazine application under agronomic management practices differing in tillage practice (conventional and zero tillage), residue management (with and without residue retention) and crop rotation (wheat-maize rotation and maize monoculture). Atrazine sorption was determined using batch and column experiments. In the batch experiment, the highest distribution coefficient K_d (1.1 L kg^?1) at 0–10 cm soil depth was observed under zero tillage, crop rotation and residue retention (conservation agriculture). The key factor in adsorption was soil organic matter content and type. This was confirmed in the column experiment, in which the highest K_d values were observed in treatments with residue retention, under either zero or conventional tillage (0.81 and 0.68 L kg^?1, respectively). Under zero tillage, the fact that there was no soil movement helped to increase the K_d. The increased soil organic matter content with conservation agriculture may be more important than preferential flow due to higher pore connectivity in the same system. The soil's capacity to adsorb 2-hydroxyatrazine (HA), an important atrazine metabolite, was more important than its capacity to adsorb atrazine, and was similar under all four management practices (K_d ranged from 30 to 40 L kg^?1). The HA adsorption was attributed to the type and amount of clay in the soil, which is unaffected by agronomic management. Soils under conservation agriculture had higher atrazine retention potential than soils under conventional tillage, the system that predominates in the study area.     

Dynamics of Policy Networks. The Case of Organic Farming Policy in the Czech Republic

To better understand the potential for successful and long-term establishment of environmental policy, the aim of this paper is to explore the network dynamics of a policy field that has become well established in the EU: organic farming. We look at the dynamics of the organic farming policy network in the Czech Republic over a period of 10 years by applying a comparative formal network analysis. We focused in particular on the distribution of power between actors and how capacities of policy actors have evolved between 2004 (its year of accession to the EU) and 2014. We conclude that the organic farming policy network in the Czech Republic has been highly dynamic and has changed from one that was decidedly influenced by organic sector organizations to a network centralized around the Ministry of Agriculture. However, the organic farming organization managed to maintain its good reputation for competence in organic farming policy, which creates opportunities for the organization to remain active in the policy debate.     

基于液气比的湿法脱硫系统的运行优化研究

石灰石-石膏湿法烟气脱硫是一种比较成熟、脱硫效率较高的脱硫技术。阐述了这种方法的化学基础和过程动力学,研究了影响烟气脱硫效率的主要因素,并讨论了液气比对提高脱硫效率和降低成本的影响。通过对某公司脱硫系统的优化调整,系统运行稳定,节能效果明显。根据机组负荷控制液气比在11 L/m3左右,脱硫系统的安全性和经济性均可保证,并有广泛地推广空间。     

Effects of Strength and Position of Pollutant Source on Pollutant Dispersion Within an Urban Street Canyon

A two-dimensional numerical model for simulating airflow and pollutant dispersion inside an urban street canyon was first developed using the FLUENT code, and then it was validated against a wind tunnel experiment. Then the effects of strength and position of pollutant sources on pollutant dispersion within an urban street canyon were investigated numerically. The numerical results showed that the dimensionless pollutant concentrations within the urban street canyon were independent from the source strength. The results also revealed that the pollutant distributions inside the urban street canyon with a two-lane road were influenced significantly by the positions of the two sources: 1) the closer the two sources were to the street center of the canyon, the lower the pollutant concentrations on the leeward wall and at the human respiration level in the leeward footpath became; 2) the pollutant concentrations on the windward wall and at the human respiration level in the windward footpath were not sensitive to the locations of the two sources as long as the source on the windward lane was situated outside the small recirculation zone at the bottom corner of the canyon windward wall; 3) the pollutant concentrations on the lower parts of the windward and leeward walls as well as in the two footpaths increased greatly when the two sources were moved from outside into the small recirculation zones.     

水生态文明建设系统要素的体系模型构建研究

水生态文明是生态文明的核心部分,水生态文明程度的高低,直接影响整个生态文明建设的进程。作为一项开拓性工作,当前亟须构建水生态文明建设的要素体系,并给出对系统关键要素进行识别及对系统要素作用机制进行动态性分析的方法。论文整合水生态文明建设的社会属性和自然属性,探究了水生态文明建设中系统要素的类型、存在形式及其传导机理,构建了包括水安全、水生态、水环境、水利用、水管理、水文化六大要素的水生态文明建设系统要素体系模型。为了验证水生态文明建设体系模型,并发掘关键要素,论文以山东省淮河流域为例,选择了22项该区域水生态文明建设体系模型中的要素,经过统计分析,得到了5项系统关键要素及其重要性排序。为更加深入细致的考察水生态文明建设系统要素的相互作用机理,论文选取前2位关键要素水利用因子和水生态环境因子为例,使用Vensim平台模拟绘制出山东省淮河流域水利用因子和水生态环境因子的系统动力学模型,综合考虑存量、速率变量与辅助变量三种变量的动力学作用关系,对该区域水生态文明建设系统关键要素的作用机制进行了分析,并从动态视角为区域内相关部门的决策制定提供了建议。研究结果表明,水生态文明建设对经济社会发展具有深远意义,将水生态文明建设系统要素归结为水安全、水生态、水环境、水利用、水管理、水文化六大要素体系模型的做法具有理论基础与实证支持,可以为政府相关管理部门对水生态文明建设的评价和管理提供方向,系统动力学分析可用于对特定区域关键影响因素的动态作用关系分析,进而发现提升水生态文明建设水平的途径。     

江西仙女湖流域大型底栖动物群落结构及水质评价

以典型的亚热带大型山地丘陵湖泊——江西省仙女湖研究为例,2014~2015年每月对仙女湖湖区及主要入湖河流进行了大型底栖动物群落的周年动态研究。经鉴定得底栖动物111种,隶属3门53科77属。其中软体动物40种,节肢动物61种,环节动物10种。优势种为中华颤蚓、梨形环棱螺、河蚬、锯齿新米虾、羽摇蚊、粗腹摇蚊属、前突摇蚊属、霍甫水丝蚓。仙女湖大型底栖动物年平息栖息密度为346 ind./m2,年平均生物量为54.26 g/m2;不同区域和季节底栖动物的栖息密度与生物量有显著差异(P0.05),河流型生境R2年平均栖息密度最大,为722 ind./m2。湖泊型生境L4年平均栖息密度最小,为251 ind./m2。1月的平均栖息密度最高,为567 ind./m2,5月平均栖息密度最低,为163 ind./m2。用辛普森多样性指数对不同区域水质进行评价,结果表明,入湖河流和钤阳湖为轻度污染,舞龙湖为中度污染。系统聚类和MDS排序分析表明,大型底栖动物的分布具有环境空间异质性,可以划分为2个群落。     

Focusing Ecological Research for Conservation

Ecologists are increasingly actively involved in conservation. We identify five key topics from a broad sweep of ecology that merit research attention to meet conservation needs. We examine questions from landscape ecology, behavioral ecology, ecosystem dynamics, community ecology, and nutrient cycling related to key topics. Based on literature review and publication trend assessment, consultation with colleagues, and roundtable discussions at the 24th International Congress for Conservation Biology, focused research on the following topics could benefit conservation while advancing ecological understanding: 1. Carbon sequestration, requiring increased linkages to biodiversity conservation; 2. Ecological invasiveness, challenging our ability to find solutions to ecological aliens; 3. Individual variation, having applications in the conservation of rare species; 4. Movement of organisms, integrating ecological processes across landscapes and scales and addressing habitat fragmentation; and 5. Trophic-level interactions, driving ecological dynamics at the ecosystem-level. Addressing these will require cross-disciplinary research under the overarching framework of conservation ecology.