城市可持续规划中的生态敏感区避让分析——以丽江市为例

为促进城市可持续发展,在科学合理规划城市空间格局的基础上,应突出强调保护原有特色生态环境要素,保育生态系统服务功能和原住民人居环境。作为世界文化遗产,丽江城市面貌在过去数十年发生了深刻变化,城市用地显著扩张,同时严峻的环境问题对城市可持续发展提出挑战。以丽江市为例,选取对其发展影响深远的水系元素、噪声环境因子和森林火灾3个关键生态敏感因子,提出通过分析这类生态敏感区在城市规划过程中的避让方法、程度,区划城市规划基本空间格局,以避免城市未来因生态环境问题突出而制约其发展的规划用地思路。结果表明,丽江城区周边湖泊水系、古城内部及周边原住民人口密集区都是保障城市可持续发展的生态保护重点地区,在城市用地规划中必须予以避让;该区域面积为147.2 km2,占研究区面积的11.1%。同时,明确给出了规划用地的具体空间控制范围和相应的避让原则。     

北京城市土地复合生态服务功效演变特征

城市的发展依赖于土地复合生态系统提供各项的生态服务功能,其产出是生态服务功效,可分为正向和负向的服务功效。快速的城市化导致的土地利用变化影响了土地的生态服务功效。在GIS平台的支持下,基于遥感影像和城市社会经济发展数据,以特大城市北京为案例城市,建立了基于正向和负向生态功效的空间指标体系,采用划分单元空间网格评价方法,评估了上一版城市总体规划实施以来土地复合生态服务功效的变化特征。研究表明由于城市化的快速发展影响了土地的复合生态功效,2003—2011年城市土地复合生态功效评价结果显示,土地的生态服务负功效在增长,而正功效在不断减少,2003年土地正负服务功效空间分别为57.7%和42.3%,2011年则分别为51.3%和48.7%。2003年的生态服务负功效空间以中心城为核心,成放射状向新城辐射;而2011年生态服务负功效空间以中心城为核心向外呈饼状蔓延;外延式的城市发展空间发展模式是导致负功效增长的主要因素。为建设良好的城市生态环境,需要在未来的城市规划和管理中,重视非建设用地的生态功能管理,引导外部生态空间渗入城市,强化土地生态服务功能;同时优化城乡结合部的用地结构,保育郊区的生态环境。     

城市水体对热岛的缓冲性能沿河岸距离的变化规律

城市水体包括城区内的自然水体和人工水体两大类。作为城市生态系统的重要组成部分,水体在缓解城市热岛效应(Urban Heat Island, UHI)上具有重要作用。研究城市热岛效应的现状,探讨水体对城市热岛的缓冲效应,为改善城市热岛效应和生态环境,并对城市进行合理的改造和规划提供理论依据。以长沙市中心城区为研究区域,以南北向贯穿长沙市的湘江河道作为主要研究对象,基于长沙市2016年7月Landsat 8 TIRS遥感影像采用大气校正法反演地表温度(Land Surface Temperature, LST),利用监督分类法获取其同步的城市化进程和土地利用类型,分析市区内地表温度及热岛效应的空间分布特征。同时,通过在湘江两侧建立多个尺度的缓冲区,并将其与地表温度分布及土地利用类型叠置,分析湘江为主的水体对长沙市热环境及各缓冲区的缓冲效应,结果表明:(1)长沙市城市建设格局与热岛效应空间分布基本相似,建筑用地热岛效应更高,极端地表温度达到53.8℃;水体、绿地和裸地的热岛效应相对较低,最低地表温度为16.0℃;(2)湘江对长沙市热岛效应具有缓冲作用,对长沙市热岛效应的平均缓冲距离为400 m;(3)湘江对热岛效应的缓冲能力与水体周边土地利用类型有关,对河东区的缓冲作用小于河西区,对沿江休闲区的缓冲效应大于沿江住宅区。综上所述,长沙市热岛效应强度与用地类型相关,建筑用地热岛效应严重;水体对热岛的缓冲效应显著,但不同缓冲区内缓冲距离存在差异,因此对城市生态格局进行小规模改造可增强水体缓冲作用,缓解城市热岛效应。     

南方丘陵山区生态安全格局构建与优化修复——以瑞金市为例

构建科学合理的生态安全格局、落实生态保护修复与空间优化是促进区域生态系统健康运行和社会经济可持续发展的重要途径。以南方丘陵山区瑞金市为例,综合生态敏感性评价与最小阻力模型,解构瑞金市生态安全格局及其自然生态与社会经济特点,并提出生态保护修复与空间优化方案。结果显示：(1)瑞金市生态源地共有123.22km~2,占总国土面积5%,主要为重要山林地和水域,环绕中部盆地呈卫星状分布;(2)潜在廊道119条,生态节点72个,在周边山地呈闭合网络状,但中部盆地廊道单一、节点密集,网络连通性较低;(3)瑞金市是典型的高原型阻力面,中部盆地城镇发展区、沟域经济延伸带、西部工矿挖采点生态阻力高、源地辐射弱,应生态预警与重点修复。瑞金市生态保护修复与空间优化应宏观统筹、分区推进、精细落实,划分生态修复核心区、生态监测预警区、生态保护缓冲区和生态保护重点区,明确空间管控原则、分区推进生态保护,围绕“源地-廊道-节点”落实生态修复。     

城市土地利用变化对生态系统服务的影响——以淮北市为例

城市是一类以人类活动为中心的社会-经济-自然复合生态系统.城市的快速蔓延及强烈的人类活动显著地改变了城市的土地利用结构,进而严重影响了城市生态系统服务及人居环境.通过遥感、GIS技术及生态系统服务价值评估等方法,对淮北市1987年、2000年和2007年3个时期20a间的土地利用结构及生态系统服务价值的演变进行定量评价.研究结果表明:1987-2007年间淮北市生态用地空间结构和面积发生剧烈变化,生态用地占城市面积的比例由91.45％降低至71.86％.1987-2000年,农田面积大幅度下降,而林地和水体都呈不同程度的增加趋势,建设用地面积增长迅速.2000-2007年,农田面积有所增加,林地和水体面积却明显下降,建设用地总面积虽然没有明显变化,但其聚集度显著增加.20年间,城市生态服务功能的价值呈现先增加后减少的趋势,在2000年达31.32亿元.2000-2007年,以废物处理和水源涵养功能退化最为严重.可见,城市土地利用结构的变化与生态服务功能密切相关,此结果可为淮北市景观格局优化及土地合理调控和管理提供一定的科学依据.     

营口市城市及村镇聚落增长与土地利用变化的模拟预测

基于辽宁省营口市1988、1992、1997、2000和2004年5期Landsat TM卫星遥感影像数据,利用城市增长和土地利用变化模拟模型SLEUTH模拟预测了6种预案（当前趋势预案、无保护预案、适当保护预案、管理增长预案、生态可持续预案和区域及城市规划预案）下2005—2030年营口市城市及农村聚落的增长和土地利用变化情况.结果表明：1988—2004年,营口市城市及村镇聚落的增长面积为14.93 km²;1997—2004年,研究区水域、园地、矿山、耕地等土地类型面积的变化较大.2005—2030年,生态可持续预案下,营口市城市及村镇聚落的面积将缓慢增长,较好地保护耕地、林地等资源,但在一定程度上将限制城市及村镇聚落的增长;无保护预案下研究区城市及农村聚落的增长速度最快,耕地流失面积较大;当前趋势预案下,耕地流失面积与无保护预案相近,但耕地流失的格局不同;适当保护预案和管理增长预案下,耕地的流失面积较小;区域与城市规划预案下,城市及村镇聚落增长主要分布在城市开发区和城市周边地区.利用不同预案下的SLEUTH模型可以模拟不同土地管理政策对城市及村镇聚落增长和土地利用变化的影响,对我国实施统筹城乡发展、建设社会主义新农村具有指导意义.     

Fast bioassessment of wastewater and surface water quality using freshwater flagellate Euglena gracilis—a case study from Pakistan

Wastewater is a big source of water pollution in the world. Selected wastewater samples from Dera Ismail Khan (D.I. Khan), a city in Pakistan, were analyzed for physicochemical and ecotoxicological properties. Samples from the Indus River before and after the municipal wastewater is discharged into it were tested to determine the effects of municipal wastewaters from D.I. Khan on the river Indus. Different parameters of the freshwater flagellate Euglena gracilis such as motility, swimming velocity, gravitactic orientation, cell shape, and photosynthetic efficiency were used as end points. Gravitactic orientation and cell shape were found to be significantly impaired by the wastewater samples. Swimming velocity and relative electron transport rate of cells were positively affected by all water samples. Quantum yield of photosystem II (F _v/F _m) was not affected, except by ghee (oil) industry effluent where it was significantly increased. Comparison of upstream and downstream samples from the Indus River showed that waste effluents from D.I. Khan affect the physicochemical and ecological properties of the river Indus.     

基于氮排放估算的区域生态风险评价——以中国台湾地区为例

随着全球人口不断成长,农业生产、工业发展、能源消耗及生活消费等人类活动不断增加,对城市区域乃至于区域生态系统均带来显著负面影响。为量化评估人类活动对区域生态系统的影响,以人类活动产生的氮排放为切入点,选择中国台湾地区为研究区,针对其高投入的农业生产、密集的交通工业设施及人口分布等背景,构建了基于氮排放的区域生态风险评价研究框架。分析了2001年至2010年中国台湾地区农业及城市系统所产生的氮排放变化情况,并在空间上比较了各县市的氮排放差异;其次,依据各用地类型特点,定义了其对氮排放压力的脆弱程度,藉以评估中国台湾地区生态风险变化及其潜在风险强度。研究结果表明中国台湾地区2005至2010年期间氮排放带来的生态风险值先降后升,主要原因源于期间农业活动产生的氮排放减少,但交通运输带来能源消耗却明显增加了氮排放;通过分区比较,确定低风险县市主要包括金门县、连江县、澎湖县、新竹市、嘉义市及基隆市,而台中市、屏东县、台南市、高雄市及新北市,由于农业生产活动密集且人口分布密度高,为中国台湾地区高生态风险区。     

大沽排污河生态修复河道水质综合评价及生物毒性影响

为了改善城市河道水质,实现排污河污染控制与修复,在天津市大沽排污河的上游代表性河段开展了河道原位生态修复工程示范。对植物修复后河道的污染状况进行了监测和分析,与清洁河道做了比较,并对水质修复效果和生物毒性影响状况进行综合分析和评价,研究生态修复示范工程对排污河水质的修复效果和生态效应。结果表明:经种植水葱等水生植物进行生态修复后,河道污染一定程度上降低,水质得到改善。大沽河主要污染是营养元素N、P污染和有机物污染,重金属污染不严重。植物修复对电导率、溶解性总固体(TDS)、盐度、氯化物有一定影响,但影响不显著;对COD等有机污染的修复效果较好,最高去除效率可达54%,但相比清洁水域值依然较高,有机污染依然较严重;对营养元素N、P没有修复效果,反而修复区有升高的趋势,相对清洁水域污染严重。主成分分析表明水质参数主要是氨氮、总氮、总磷代表的营养元素及pH值、DO、电导率、TDS、盐度和氯化物,综合评定结果显示修复区域芦苇根部水质最好;聚类分析将17个水质指标分成5类,并与主成分分析结果显示出一致性。植物根际周边的微生物数量多,群落多样性高。植物修复对水样植物毒性影响明显,能降低其毒性;水样对发光菌均具有毒性作用,存在潜在的急性生物毒性;修复区水样对水生动物大型蚤不存在急性生物毒性。     

Ecological engineering analysis and eco-hydrodynamic simulation of tidal rivers in Shenzhen City of China

A comprehensive approach using ecological engineering analysis and eco-hydrodynamic simulation was conducted on the tidal rivers in Shenzhen City of China in this study. A tidal river along a near-shore city should be evaluated and regulated from a multidisciplinary point of view, focused especially on ecology, in order to maintain and enhance the ecological structure and function of the river. Firstly, eco-hydrodynamic control can be used, based on simulated modeling of tidal water circulation, to trace the distribution of pollutants and to predict circulation of tidal water. Using findings from this modeling effort, some water control facilities, such as additional channel connection and water gates, can be established. Appropriate operation strategy is to use tidal energy to promote effective water exchange in the water bodies and thereby improve water quality in the tidal river. Secondly, ecological engineering methods should be integrated with hydraulic measures to further improve the environment. Appropriate plant communities for this ecological engineering can be selected. Based on the simulated results of eco-hydrodynamic model, the optimum locations for adding reclaimed land can be determined. These ecological engineering methods are as follows: (1) it is necessary to calculate the ecological water requirements for the tidal river. The water effluent from the sewage treatment plant can be considered as reclaimed water and pumped to upstream of the tidal reach for reuse; (2) well planned aquatic plant systems composed of emergent, floating, and submergent plants can be used to promote water treatment; (3) the configuration of the engineered landscape should give preference to indigenous plants and appropriate non-indigenous plant species; (4) constructed wetlands, especially mangroves at coastal city sites, can also improve the tidal river aquatic environment.     

Fish-habitat relationship in a tropical river under anthropogenic influences

This study analyzes the interaction of fish assemblages with 14 physicochemical and hydrogeomorphological variables at 31 sampling stations along the watershed of the Meia Ponte River, Upper Paraná Basin, Central Brazil, during low and high water seasons in 2001. This river and its tributaries drain both urban and agricultural areas. Fish were caught with sieves along a 100 m stretch demarcated in every sampling site, where environmental variables were also measured. A total of 3508 individuals belonging to 31 species were collected. Fish abundance and environmental data matrices were submitted to a multivariate analysis of co-inertia. Two axes were retained for interpretation (total variance explained = 63.65%) indicating that pH, water temperature, conductivity, chemical dissolved oxygen, and turbidity, all have an influence on fish assemblage structure. The co-structure found (fish assemblages and physicochemical variables) is correlated in both of the axes considered (r = 0.73 and r = 0.68, respectively), and is statistically significant (Monte Carlo test, P < 0.001). This co-structure is regulated by seasonality, but is influenced by fish habitat preferences, spawning and available food, the extent and effects of anthropogenic activities (domestic sewage, agriculture, ranching, urban areas) and the position of sampling stations along the watershed. Handling editor: S. M. Thomaz     

Microbiological implications of periurban agriculture and water reuse in Mexico City

Background

Recycled treated or untreated wastewater represents an important health challenge in developing countries due to potential water related microbiological exposure. Our aim was to assess water quality and health implications in a Mexico City periurban agricultural area.

Methodology/Principal Findings

A longitudinal study in the Xochimilco wetland area was conducted, and 42 sites were randomly selected from 211, including irrigation water canals and effluents of treatment plants. Sample collection took place during rainy and dry seasons (2000–2001). Microbiological parameters (total coliforms, fecal coliforms, streptococci/enterococci, and bacteria other than Vibrio grown on TCBS), Helicobacter pylori, and physicochemical parameters including trihalomethanes (THM) were determined. Fecal coliforms and fecal streptococci are appropriate indicators of human or animal fecal contamination. Fecal coliform counts surpass Mexican and World Health Organization irrigation water guidelines. Identified microorganisms associated with various pathologies in humans and domestic animals comprise Escherichia coli, Klebsiella spp., Salmonella spp., Enterobacter spp., Enterococcus spp., and Pseudomonas spp; H. pylori was also present in the water. An environmental characteristic of the canal system showed high Total Organic Carbon content and relatively low dissolved oxygen concentration; residual chlorine as a disinfection control is not efficient, but THMs do not represent a problem. During the rainy season, temperature and conductivity were higher; in contrast, pH, dissolved oxygen, ammonia, and residual chlorine were lower. This is related with the continuous load of feces from human and animal sources, and to the aquatic systems, which vary seasonally and exhibit evidence of lower water quality in effluents from treatment plants.

Conclusions/Significance

There is a need for improvement of wastewater treatment systems, as well as more efficient monitoring, regulation, and enforcement procedures for wastewater disposal into bodies of water.     

沈阳市城市空间扩展的生态安全格局

在分析沈阳市1956-2004年6个时期市区空间扩展规律及其原因基础上,选择地势地貌、地面塌陷危害、水体(河流湖泊和水田)、林地、基本农田和土壤污染6个生态控制因子,将城市拓展区分为优先发展、适合发展、限制发展和严禁发展4个等级,最终形成生态安全格局,揭示了生态安全保障下城市空间扩展的趋势和方向.结果表明:1956-2004年建成区持续扩增;2000年前,沿着浑河在东北-西南轴向延伸程度较大;2001-2004年城市集中向南、跨越浑河开发了浑南新区.沈阳市发展初期,其格局主要由工业生产力布局塑造,政治、经济因素为主导,至2004年,建成区面积已达291 km2,再继续扩张,生态因素将成为城市发展的重要限制因子之一.生态安全格局显示东部、西部发展受到限制;北部、南部和西南部存在较大发展空间,尤其南部扩展空间更大,可以以南部为主要扩展方向.     

Drinking water quality and human health risk evaluations in rural and urban areas of Ibeju-Lekki and Epe local government areas,Lagos, Nigeria

Abstract

This study evaluated the drinking water quality and associated human health risks in three (3) rural and urban areas each in Ibeju-Lekki and Epe local government areas of Lagos, Nigeria. Two hundred structured questionnaires were administered to stakeholders, and samples were obtained from prevailing drinking water sources in the study areas using standard methods for microbiological, physicochemical, heavy metals and human health risk evaluations. Wells and boreholes were the major sources of drinking water in the rural and urban areas, respectively. Drinking water samples from the study areas contained more than one pathogenic bacterium. The physicochemical parameters except total organic carbon (TOC) were within permissible limits of the Nigerian Standard for Drinking Water Quality (NSDWQ). The mean values of Cd and As exceeded the maximum permissible limit of NSDWQ. The hazard quotient of cadmium and arsenic was greater than 1 indicating potential health risks if the water is not treated. In order to achieve the UN Sustainable Development Goal 6 on clean water and sanitation by the next decade (2030), we recommend that frequent monitoring, treatment and stakeholders education on drinking water treatment techniques should be actively conducted particularly in rural areas in the state, country, region and continent.     

城市河流的景观生态学研究:概念框架

城市河流作为城市景观中一种重要的生态廊道,其功能的正常实现与否关系到整个城市的可持续发展。通过分析当前城市河流的研究概况,发现应用景观生态学原理对城市河流展开多尺度、多学科的综合研究是实现“自然-人类-水体”可持续发展的必然趋势。从景观生态学的角度出发,结合城市河流的特点,提出了更为综合的、景观水平上的城市河流研究的概念框架。特别针对景观生态学研究的核心问题,对城市河流的研究尺度、格局分析、干扰程度等重要方面进行了详细论述,以期在景观水平上构建城市河流的可持续发展预案。     

基于生态绿当量的城市土地利用结构优化——以宁国市为例

基于生态绿当量的概念,探讨了城市生态用地合理性的生态标准,构建了土地利用结构优化模型。并在此基础上,以安徽省宁国市为例对该研究区不同空间范围下生态用地的结构及其优化方法进行实例分析。分析结果表明:宁国市域和城乡结合部均达到最佳绿地覆盖率的要求,而城区综合绿当量仅为0.66,需要进行用地调整。市域、城乡结合部和城区3个空间范围下的绿容率(GPR)分别为:4.89、4.22和2.77,可见城区绿化结构简单,树种单一,乔木和水体景观缺乏。同时,城区人口密集,但绿地生态系统服务功能较低,人均绿地率(ELP)仅为41.7 hm²/人。由此提出宁国市城区土地利用结构的优化调整方案,通过整个城市中心增绿、外围拓展;路林结合,蓝、绿交融,城乡一体,构筑内外环抱的多功能、多效益、完整的城市发展生态网架,保障城市长远的生态安全,促进良好的城市生态环境的形成。     

西安市城乡建设用地时空扩展及驱动因素

城乡建设用地变化及驱动机制是国内外研究的热点领域,我国正处在城镇化快速发展时期,建设用地的迅速扩张已成为当前中国土地利用变化的主要特征。以5期(1975、1990、2000、2005和2010年)土地利用现状数据为基础,利用GIS空间分析技术,提取建设用地变化及空间分布信息,利用建设用地扩展指数和建设用地密度分析方法对近35年来(1975—2010年)西安市建设用地扩展的时空特征进行分析。并结合社会经济数据,对建设用地空间扩展驱动力进行分析。结果表明:西安市建设用地面积急剧增长,建筑密度不断加大,并且城乡空间差异较大。西安市建设用地扩展是多因素综合作用的结果,高程和坡度控制着建设用地的分布格局,城市沿河谷扩展。西安市城市建设应加强区域宏观规划和土地利用详细规划,切实保护秦岭北麓林草地,加强历史文化名城特色,避免低层次文化复古创修。     

海口市生态用地变化与安全格局构建

城市化过程中,城市生态用地变化与安全格局构建对于城市生态系统健康、城市居民生活质量和城市可持续发展有着重要意义,生态用地的变化直接影响生态安全格局变化,生态用地安全格局又对生态用地的规划有指导作用。基于GIS技术,对海口市1991年至2016年生态用地的时空变化过程进行研究,进而分析生态用地演变。选取高度、坡度、水资源安全作为生态安全影响单因子,并分级赋值,构建综合生态用地分布格局。以底线型生态用地为源,基于最小累计阻力模型(MCR),以阻力阈值作为分级边界,划分不同安全水平的生态用地区域,进而确定源间生态廊道、辐射道与战略点,构建生态用地安全格局。分析结果表明:1991年至2016年,海口市三类生态用地变化最大,其中林地减少13.33%,园地增加9.136%,坑塘水面增加3.71%。南渡江以西生态用地从以林地为主转为园地与建设用地为主,其余地区变化较少。生态用地安全变化区域集中在海口市西部与东部,其中西部高安全水平区减少,整体安全水平急剧恶化,东部高安全水平区略有提升。故需要制定和实施合理的生态用地保护政策,对生态用地格局进行优化调整,以期构建区域内生态环境协调发展的可行方案。     

基于地质灾害敏感性的山地生态安全格局构建——以云南省玉溪市为例

区域生态安全格局构建作为景观生态学的研究热点之一,为区域可持续发展和国土生态屏障建设提供了重要途径,尤其对于灾害频发、生态脆弱的滇中地区,其能够有效规避自然灾害、促进区域生态系统和社会经济系统协调发展.本文以玉溪市为例,针对区域生态环境基底特征,选取水源涵养、固碳释氧、土壤保持和生物多样性等生态系统服务评估自然生境重要性,综合考虑单一类型生态系统服务质量和多功能性识别生态源地;并采用地质灾害敏感性修正基于地类赋值的基本阻力面,运用最小累积阻力模型识别生态廊道,从而构建玉溪市生态安全格局.结果表明: 玉溪市生态源地斑块数量为81个,占玉溪市土地总面积的38.4%,与各级自然保护区重合率达75.2%,主要分布在市域西部的山林地和东部的湖泊湿地区域;玉溪市生态廊道总长度1642.04 km,呈“一横三纵”的空间分布格局,沿河谷、断陷盆地等植被覆盖较好的区域延伸.本文针对滇中山地生态脆弱区地质灾害频发特征,构建山地生态安全格局,对于区域山地开发与生态保护能够提供决策指引.     

Heterogeneity of apolipoprotein E polymorphism in different Mexican populations

Mexico has approximately 100 million inhabitants. Most of the urban Mexican population has been considered mestizo (Indian and Spanish descent), whereas the Indian population predominates in rural areas and small towns in the countryside. In this study we analyzed the apolipoprotein E (APOE) polymorphism in Guadalajara (the second largest metropolitan area of Mexico) and its surrounding areas, two adjoining states (Nayarit and Durango), and an Indian town (Huichol Indians) from western Mexico. APOE*3 was the most common allele, and APOE*3/*3 was the most common genotype in all populations studied. Guadalajara revealed the highest frequency of the APOE*2 allele (7.8%); the frequency decreased in the rural area (4.4%), followed by Nayarit (1.6%), and was absent in Durango and in the Huichols. On the contrary, the lowest frequency of the APOE*4 allele was in Guadalajara (8.4%); the frequency increased in the rural area (9.3%), in Nayarit and Durango (11.5% and 11.7%), and reached a high frequency in the Huichol Indians (28%). The distribution of the APOE allele in the western population of Mexico is similar to those described in Mexican American migrants living in the United States but is different from those populations living in Mexico City. This study shows the heterogeneity of the Mexican population, where the frequency of the APOE*2 allele is higher in Guadalajara than in other urban areas of Mexico and is similar to frequencies described in the Caucasian population. On the contrary, the Huichols revealed the highest frequency of the APOE*4 allele in Mexico and in the Americas. This information could be useful for the study of dyslipidemias associated with chronic diseases and as markers of ethnic variation in the Americas.