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1.
应用TM影像分析南京城市生态绿地格局   总被引:13,自引:0,他引:13  
应用遥感和GIS技术对南京城市生态绿地格局进行分析研究,研究中试用NDVI波段及其它波段组合对南京城市植被进行解译,效果较好,研究结果表明,南京生态绿地分布很不平衡,并提出南京生态绿地建设的合理化建议。  相似文献   

2.
成都市生态城市建设的路径设计   总被引:5,自引:0,他引:5  
文章结合成都市自然资源的优势和特点,依据生态原理的基本思想,从城市河流生态的保护与建设;成都绿化的生态建设与城市生态社区示范建设;城乡融合生态系统的基本设计;成都郊县市生态农业、生态聚落的建设和生态建设总体布局与功能分区等五个方面进行了具体的分析,提出了相关的设计路径和措施。  相似文献   

3.
世界各国都在研究解决大城市的交通问题,其研究解决的共同特点是着重考虑速度快、时间准、距离长、运能大、质量高、造价低、对城市环境污染少等方面的原则。单纯从扩宽和延长线路,增加车辆已远远不能满足当前大城市的交通运输量的要求。为了减少地面交通的拥挤,改善大城市的环境噪声,世界各国都采取向地下和地面空间发展城市快速轨道交通,取代了多年来一直以公共汽车和电车为主体的城市交通。本文根据我国的国情和我国大城市的特点,参考国外的经验,在建设城市快速轨道交通时,如何保护和治理城市环境少受污染和影响方面,提出了一些具体的措施和建议,并对如何评价快速轨道交通对城市环境的影响,提出了评价的方法、步骤、内容、范围等。  相似文献   

4.
讨论了城市环境问题的生态学实质,国际城市人居环境生态学研究动向,以及城市人居环境建设的生态转型方法,重点介绍了城市人居环境规划中的系统化,自然化,经济化,人性化趋势,并从观念与目标的转型,规划与设计的转型和技术与材料革新等方面探讨了城市生态建设的转型方法。  相似文献   

5.
城市发展中存在的问题与发展趋势   总被引:3,自引:0,他引:3  
从可持续发展的角度,以中国为例讨论了城市化及城市发展中存在的问题,主要表现有:(1)城市建设与发展偏离了城市历史脉络;(2)少数大城市规模过度膨胀,一些小城市发展缓慢;(3)产生大量产品和废物,缺乏循环再生能力;(4)钢筋混凝土充斥城市,缺乏生态活力和灵气;(5)缺乏共生和自生能力。生态城市由于具有时间发展有序、空间布局合理、代谢过程完善、产业结构合理,体制健全、景观多样性丰富、竞争、共生、自生等特点和优势,必将成为是21世纪城市唯一、必然的选择。  相似文献   

6.
《城市环境与城市生态》2010,23(5):F0002-F0002
一、《城市环境与城市生态》办刊宗旨是以城市、城镇为对象,开展城市环境与城市生态领域的学术讨论,报道国内外环境科学和城市生态学最新技术和研究成果及其有关的科技动态,以达促进城市建设、经济发展与环境建设协调发展的目的,为保护与改善城市环境服务。  相似文献   

7.
《城市环境与城市生态》2010,23(4):F0002-F0002
一、《城市环境与城市生态》办刊宗旨是以城市、城镇为对象,开展城市环境与城市生态领域的学术讨论,报道国内外环境科学和城市生态学最新技术和研究成果及其有关的科技动态,以达促进城市建设、经济发展与环境建设协调发展的目的,为保护与改善城市环境服务。  相似文献   

8.
南京城市西部历史时期是城市的重要边界,现在逐渐演变成老城与新区之间的核心地带,成为公共活动的重要地区,保护其自然、文化遗产和生态环境具有非常重要的意义。在对其现状调查分析的基础上,梳理遗产点的历史概况、现状及其分布情况,提出规划遗产廊道的意义,探讨规划的具体思路,为南京遗产保护提供了新的视角。  相似文献   

9.
南京城市土壤重金属含量及空间分布特征   总被引:13,自引:0,他引:13  
研究了南京城市土壤重金属含量、来源及空间分布特征。结果表明,南京城市土壤中V、Mn、Co、Ni、Cr污染不明显,但受到了不同程度的Cu、Pb、Zn、Sb、Hg、Cd污染,其中Hg污染比较严重。V、Mn、Co、Ni、Cr含量之间均呈极显著正相父;Cu、Pb、Zn、Sb、Hg、Cd含量之间也均呈极显著正相关。南京城市土壤V、Mn、Co、Ni、Cr主要继承了原土物质;Hg、Cd、Pb主要来源于城市燃煤、机动车尾气及工厂排放粉尘;Sb主要来源于机动车尾气和工厂排放粉尘。南京城市土壤Hg、Cd、Pb、Sb含量空间分布规律非常相似,均表现为外围向市中心有逐渐增加的趋势,并且在新街口—鼓楼、梅山硫铁矿形成异常高值的岛状、环状区域。  相似文献   

10.
城市河流在城市生态建设中的意义和应用方法   总被引:55,自引:2,他引:53  
城市河流是城市生态系统的重要组分之一。本文分析了城市河流在城市生态建设中的水源地,减弱城市热岛效应和洪涝灾害,绿地建设基地,景观多样性的组成,物种多样性保护,组成捷交通,亲近自然场所,自然教育标本等方面的多种意义,指出保持河流的自然地貌特征,维持自然水文过程,控制城市河流水污染,综合规划城市河流与城市建设的关系是发挥城市河流在城市生态系统中作用的基本方法。  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

13.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

14.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

15.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

16.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

17.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

18.
Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.  相似文献   

19.
Effects of Coffee Management on Deforestation Rates and Forest Integrity   总被引:1,自引:0,他引:1  
Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km2 around Bonga and 3000 km2 in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques  相似文献   

20.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central  相似文献   

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