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941.
环境风险区划是区域布局型环境风险管理及环境风险分区管理的重要手段.本研究在环境风险系统理论的指导下,借鉴“自上而下”和“自下而上”传统区划方对上海市突发环境风险进行区划研究.上海市突发环境风险区划中“自上而下”环境风险一级区的划分是依据上海市1990~2008年突发污染事故历史时空格局获得;而“自下而上”是通过构建上海市风险区划指标体系,在对指标进行概念模型量化的基础上,运用基于遗传算法的K均值聚类在最小区划单元进行聚类区划,并依据上海市政府宏观规划对聚类后的图斑碎块进行科学性和实用性调整,获得上海市突发环境污染事故风险亚区和小区;将上海市突发环境风险一级区及亚区和小区集成分析,实现上海市突发环境污染事故风险综合区划.结果表明:上海市突发环境污染事故风险区划包含2个风险一级区,5个风险亚区和21个风险小区,客观揭示了上海市突发环境污染事故风险的空间分布规律.针对上海市布局型环境风险和不同风险区提出相应的管理措施,为上海市综合减灾降险和风险管理决策提供科学依据. 相似文献
942.
入侵植物加拿大一枝黄花和本地一枝黄花的遗传多样性比较 总被引:1,自引:0,他引:1
为了阐明加拿大一枝黄花成功入侵的机制,利用简单序列重复区间标记(ISSR)方法对加拿大一枝黄花和本地一枝黄花的遗传多样性进行比较研究。从100条引物中筛选出12条引物用于PCR扩增,利用POPGEN32软件对2种一枝黄花进行遗传多样性分析。结果表明,加拿大一枝黄花在物种水平上的多态位点百分率为95.19%,Nei’s基因多样性指数为0.308 5,Shannon’s信息指数为0.415 8;本地一枝黄花在物种水平上的多态位点百分率(89.80%)、Nei’s基因多样性指数(0.249 1)和Shannon’s信息指数(0.383 4)都比加拿大一枝黄花小。加拿大一枝黄花和本地一枝黄花居群间遗传分化系数分别为0.118 2和0.131 3,居群内变异分别为0.881 8和0.868 7,表明2个物种居群间的遗传分化不明显,遗传一致度高,且主要的遗传变异存在于居群内。入侵植物加拿大一枝黄花具有较高遗传多样性,且高于本地一枝黄花,这可能是加拿大一枝黄花成功入侵的原因之一。 相似文献
943.
944.
RULON W. CLARK WILLIAM S. BROWN RANDY STECHERT KELLY R. ZAMUDIO 《Conservation biology》2010,24(4):1059-1069
Abstract: Anthropogenic habitat modification often creates barriers to animal movement, transforming formerly contiguous habitat into a patchwork of habitat islands with low connectivity. Roadways are a feature of most landscapes that can act as barriers or filters to migration among local populations. Even small and recently constructed roads can have a significant impact on population genetic structure of some species, but not others. We developed a research approach that combines fine‐scale molecular genetics with behavioral and ecological data to understand the impacts of roads on population structure and connectivity. We used microsatellite markers to characterize genetic variation within and among populations of timber rattlesnakes (Crotalus horridus) occupying communal hibernacula (dens) in regions bisected by roadways. We examined the impact of roads on seasonal migration, genetic diversity, and gene flow among populations. Snakes in hibernacula isolated by roads had significantly lower genetic diversity and higher genetic differentiation than snakes in hibernacula in contiguous habitat. Genetic‐assignment analyses revealed that interruption to seasonal migration was the mechanism underlying these patterns. Our results underscore the sizeable impact of roads on this species, despite their relatively recent construction at our study sites (7 to 10 generations of rattlesnakes), the utility of population genetics for studies of road ecology, and the need for mitigating effects of roads. 相似文献
945.
946.
基因工程菌在富营养化水体中应用的试验研究 总被引:6,自引:0,他引:6
实验模拟了自然状况下水体富营养化的一般过程。利用基因工程菌消氮细菌及沉淀细菌对实验水体进行生物修复。得出:在微生物处理下,水体的营养物质浓度不断降低,水体的浊度下降,透明度升高,使得实验水体的水质得到了明显的改善。 相似文献
947.
污染土地再开发是城市土地可持续利用的关键。为进行废弃农药厂的生态风险评价,采集常州市某废弃农药厂污染场地6个不同区域的土壤样品(编号为S1、S2、S3、S4、S5和S6),选取发光细菌、大型溞和蚕豆根尖细胞为试验生物,运用成组生物毒性试验对6个土壤样品的浸出液进行生物毒性检测。结果表明:6个土壤样品的浸出液都具有急性毒性和遗传毒性;发光菌和大型溞急性毒性试验表明,S3和S5的土壤浸出液毒性最高,S6的土壤浸出液毒性最低;蚕豆根尖微核遗传毒性试验表明S3和S5的土壤浸出液毒性最高,S4和S6的土壤浸出液毒性最低。蚕豆根尖微核遗传毒性试验结果与发光菌和大型溞急性毒性效应基本相同,表明成组生物毒性测试法可以用于污染土壤浸出液的毒性评价。污染物质和毒性检测结果的相关性分析结果表明,土壤中所含污染物种类和浓度已经对土壤毒性效应产生影响,结合化学分析与生物毒性检测可为污染场地进行综合评价与风险评估提供依据。 相似文献
948.
钢桥因具有跨径大、承载能力强、施工工期短等特点,被世界各国广泛采用,但在使用过程中,由于重载甚至超载车辆的反复作用、自然灾害的侵袭及交通事故等人为因素的作用,经常造成桥梁损伤和局部破坏,导致桥梁承载能力和耐久性的降低,甚至影响到运营的安全。本文建立了钢拱桥的健康检测和安全评价方法,采用防腐涂层厚度测定、结合强度测定、无损探伤和动静载荷试验等手段对紫下大桥健康状况进行了检测,采用不确定层次分析法对大桥进行了安全评价,提出了处理意见和措施,为既有钢拱桥的健康检测、评价和维护积累了有益的资料。 相似文献
949.
Biodiversity versus emergencies: the impact of restocking on Animal Genetic Resources after disaster
Heffernan C 《Disasters》2009,33(2):239-252
Restocking is a favoured option in supporting livelihoods after a disaster. With the depletion of local livestock populations, the introduction of new species and breeds will clearly affect biodiversity. Nevertheless, the impact of restocking on Animal Genetic Resources has been largely ignored. The aim of this paper, therefore, is to examine the consequences of restocking on biodiversity via a simple model. Utilising a hypothetical project based on cattle, the model demonstrates that more than one-third of the population was related to the original restocked animals after three generations. Under conditions of random breed selection, the figure declined to 20 per cent. The tool was then applied to a donor-led restocking project implemented in Bosnia-Herzegovina. By restocking primarily with Simmental cattle, the model demonstrated that the implementation of a single restocking project is likely to have accelerated the decline of the indigenous Buşa breed by a further nine per cent. Thus, greater awareness of the long-term implications of restocking on biodiversity is required. 相似文献
950.
Urban planning involves compromise between the diverse and often contradictory issues supported by the different stakeholders. The literature generally agrees on the need to broaden the participation base to overcome this difficulty. However, participation should not be limited to problem solving, but should also take place in the problem setting phase. This paper proposes a participatory diagnosis process for structuring the problem setting phase. We describe an experiment in a participatory diagnosis conducted with the residents of a Geneva neighborhood. The experiment began by identifying the residents' concerns, which were then reformulated under broader issues. Some 20 spatial indicators were built using GIS tools, and were then applied in a second phase of resident consultations to assess the relative importance of each issue. The ensuing priority issues formed the core of the diagnosis. The approach emphasized comparison between the daily experiences of residents and so-called official information (i.e. census tract, traffic measurement, and so on). The residents were therefore involved in a learning process that allowed them to consolidate or modify their opinions. The process led to the emergence of a clearly defined collective awareness that supplanted individual aspirations. 相似文献