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491.
文章首先对藻类污染生态学的发展历史作了简单回顾,接着对其主要研究领域(水污染对藻类的影响和藻类净化水质)及研究成果进行了综述,在此基础上指出了其今后的发展趋势。  相似文献   
492.
We assessed relationships between environmental characteristicsand macroinvertebrate assemblages in lotic habitats of California's Central Valley with community metric and multivariate statistical approaches. Using canonical ordinationanalyses, we contrasted results when assemblage structure was assessed with macroinvertebrate metrics, as suggested for use inindices of biotic integrity, or with genera abundances. Our objectives were to identify metrics or taxa diagnostic of loticenvironmental stressors and compare the capacity of theseapproaches to detect stressors in order to suggest how they mightbe used to diagnose stressors. For macroinvertebrate metrics,redundancy analysis (RDA) extracted three axes correlated withchannel morphology and substrates. For genera abundances, canonical correspondence analysis (CCA) extracted two axescorrelated with soluble salts and with channel morphology andsubstrates but did not separate these gradients onto differentaxes. Cluster analyses identified five RDA and five CCA sitegroups, which exhibited differences for environmental variables,metrics, or genera abundances, and agreement between the analysesin partitioning of sites was greater than if sites were partitioned randomly. These approaches differ in their abilityto detect environmental stressors, because they measure differentaspects of assemblages and would be complementary in design ofnew metrics diagnostic of stressors.  相似文献   
493.
《Ambio》2021,50(12):2286
Exploitation of natural forests forms expanding frontiers. Simultaneously, protected area frontiers aim at maintaining functional habitat networks. To assess net effects of these frontiers, we examined 16 case study areas on five continents. We (1) mapped protected area instruments, (2) assessed their effectiveness, (3) mapped policy implementation tools, and (4) effects on protected areas originating from their surroundings. Results are given as follows: (1) conservation instruments covered 3–77%, (2) effectiveness of habitat networks depended on representativeness, habitat quality, functional connectivity, resource extraction in protected areas, time for landscape restoration, “paper parks”, “fortress conservation”, and data access, (3) regulatory policy instruments dominated over economic and informational, (4) negative matrix effects dominated over positive ones (protective forests, buffer zones, inaccessibility), which were restricted to former USSR and Costa Rica. Despite evidence-based knowledge about conservation targets, the importance of spatial segregation of conservation and use, and traditional knowledge, the trajectories for biodiversity conservation were generally negative.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01628-5.  相似文献   
494.
头屯河流域在主要河道上修建2处拦河水库及多处引水工程,虽然每年不同程度,周期性向拦河控制性工程以下河段下泄河道生态水量,但是尚未分析论证下泄的河道生态水量及下泄周期是否满足全年河道生态需求。尤其在枯水季节头屯河水库下游往往干涸断流,洪水季节易发污染事故,河道生态达不到预期保护效果。河道生态基流分析计算及提出头屯河流域生态保护的保障措施已经到了非解决不可的地步,河道生态基流分析计算成果作为流域水行政主管部门提出头屯河流域生态保护的保障措施的重要技术支撑,从水资源合理利用与节约,河道两库联合调度、合理利用,维护水生态、保障河道基流量等方面进行工程、调度及制度建设。  相似文献   
495.
本文在阐述3S技术特点的基础上,以四川省木里县梭罗沟金矿改扩建工程所在地的梭罗沟和如米沟为研究区,介绍了3S技术在景观格局信息提取的技术要求、数据收集和工作流程,并对研究区景观格局的提取结果进行了动态变化预测与分析。实例研究证明,3S技术是景观生态学研究的重要技术工具,应用3S技术开展矿产资源开发景观格局动态评价,可以准确、快速地提取景观格局的主要特征指标,掌握景观格局现状、预测其动态变化特征、揭示其变化规律,满足区域景观格局研究的要求。本研究方法适用于生态类建设项目或区域开发规划的景观格局中短期动态预测研究,不宜用于景观格局长期的动态预测。  相似文献   
496.
通过调查与分析合肥市农业观光园的现状,得出目前合肥市农业旅游观光园存在的问题。结合桃蹊农业桃主题生态园案例分析,指出农业旅游观光园需以特色农业为主题,景观规划鲜明,进行多层次、多元化发展才能达到可持续发展的目的,从而带来更多的经济效益、社会效益和生态效益。  相似文献   
497.
德州市是我国北方土壤盐碱化和次生盐渍化分布最典型的地区之一,20世纪50至60年代就率先在全国进行土壤改良试验,改良成果突出。但是在投入巨资进行工程建设的同时,次生盐渍化现象并没有得到根本性改变,反而出现反弹现象。运用地学原理分析了研究区土壤盐碱化和次生盐渍化的分布和成因,总结出区域盐碱地整治和改良措施,运用生态学和景观生态学原理提出研究区盐碱资源开发利用的经济、社会和生态价值,以及盐碱资源可持续利用的新思路和建议。  相似文献   
498.
Abstract: A stream mesocosm experiment was conducted to study the ecosystem‐wide effects of two replicated flow hydrograph treatments programmed in an attempt to compare a simulated predevelopment condition to the theoretical changes that new development brings, while accounting for engineering design criteria for urban stormwater management. Accordingly, the treatments (three replicates each) differed in base flow between events and in the rise to, fall from, and duration of peak flow during simulated storm hydrographs, which were triggered by real rain events occurring outside over a 96‐day period from summer to fall, 2005. Incident irradiance, initial substrate quality, and water quality were similar between treatments. Sampling was designed to study the interactions among the treatment flow dynamics, sediment transport processes, streambed nutrients, and biotic structure and function. What appeared most important to the overall structure and function of the mesocosm ecosystems beyond those changes resulting from natural seasonality were (1) the initial mass of fines that infiltrated into the gravel bed, which had a persistent effect on nitrogen biogeochemistry and (2) the subsequent fine sediment accumulation rate, which was unexpectedly similar between treatments, and affected the structure of the macroinvertebrate community equally as the experiment progressed. Invertebrate taxa preferring soft beds dominated when the gravel was comprised of 5‐10% fines. The dominant invertebrate algal grazer had vacated the channels when fines exceeded 15%, but this effect could not be separated from what appeared to be a seasonal decline in insect densities over the course of the study. Neither hydrograph treatment allowed for scour or other potential for flushing of fines. This demonstrated the potential importance of interactions between hydrology and fine sediment loading dynamics on stream ecosystems in the absence of flows that would act to mobilize gravel beds.  相似文献   
499.
新疆艾比湖流域平原区景观土壤属性特征研究   总被引:1,自引:0,他引:1  
以新疆艾比湖流域平原区为对象,在对研究区进行景观生态分类及野外调查验证的基础上,利用"3S"技术将1∶100×104的新疆土壤类型图与研究区景观类型图叠加,从土壤属性层次上对研究区各类景观的生态土壤类型进行确认,并分析其在研究区内分布的特征。结果表明:研究区主要土壤类型为26类,以石膏灰棕漠土所占比例最大,占研究区总面积的19.03%,棕钙土、荒漠风沙土、草甸盐土、盐化草甸土、和灌耕灰漠土等面积也较大。  相似文献   
500.
The debate on diversity–stability relationships has a long history of theoretical interest and plays a central role in development of modern ecology. But such debate has recently re-opened under critical scrutiny both in theoretical and empirical studies. In this paper we use allometric (or energetic) scaling and statistical physics approaches to this problem. On the basis of local Damuth symmetry, a Markov model of transfer of energy between different species, and the fluctuation–dissipation theorem, scaling rules of species number and population variability of biological communities near equilibrium are derived. These scaling rules indicate that the diversity–stability relationship may be an energetic and thermodynamic consequence of ecological systems near equilibrium, not a simple statistical consequence as derived by other recent theoretical work.  相似文献   
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