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House Sparrow was the most abundant bird species near human habitat until few years back. But from the mid of twentieth century, the declining trend of House Sparrow has been reported from various countries. It has already been red listed in Netherlands and UK. Researches indicate the declining trend of House Sparrow in different cities of India like Delhi, Mumbai and Bengaluru. A 3-month wide survey has been conducted to get a preliminary idea about the distributional trend of House Sparrow in greater Kolkata. Depending on nature of urbanization and human habitat, greater Kolkata, has been subdivided into four regions (Planned City, Highly dense city, Medium dense city and Low dense city regions). In high density urban region the avian density recoded was highest, although avian diversity was maximum in medium and low dense city regions and minimum in planned city. Among 20 observational units of planned city region, House Sparrow has been noticed in 6 units and crow in all units. Among 115 observational units of rest of the regions of greater Kolkata, House Sparrow was observed in 79 units and crow in 98 units. The preliminary information revealed from this survey indicates towards negative relationship between urbanization and House Sparrow population in greater Kolkata and this negative influence is maximum in planned urban region. The presence of sufficient number of House Sparrow in any region indicates environmental stability of that region. So the declining trend of House Sparrow population in greater Kolkata, particularly in planned city region, indirectly gives the evidence of serious environmental degradation.  相似文献   

3.
Butterflies (Insecta: Lepidoptera) contribute to the ecosystem services and thereby qualify as a group deserving conservation effort. Information on the butterfly-plant links is used as a foundation to sustain population and enhance conservation and management. Thus, in the present study, the structure of a butterfly-plant network in an urban landscape like Kolkata, India, was deciphered highlighting metrics like degree distribution, nestedness, and interaction strength and specialization index. A total of forty eight butterfly species associated with thirty different angiosperm plant species were observed during the study period of one year. While Lantana camara was observed to be the dominant plant species with 37 links to different butterflies, the Catopsilia pyranthe butterfly species was dominant in terms of the generalist pattern of links (21 links) with the plants. Differential ability of the shrubs and herbs in the sustenance of the butterflies was reflected in the network indices using the herbs and the shrubs, separately. In urban landscapes with restricted variety of flowering plants, an estimate of relative strength of interactions enables identification and further use of the concerned species in sustaining butterfly populations. In accordance with these propositions, the butterfly-plant network illustrated in the present instance may prove useful in selection of plant species required for the enhancement of population of desired butterfly species in urban areas like Kolkata, India.  相似文献   

4.
生态安全格局旨在维护景观格局的整体性与生态过程的连续性,以保障城市生态安全.当前的生态源地识别方法缺乏对生态用地退化风险以及人类生态需求的考虑.本研究以武汉市为例,从生态用地质量、生态退化风险以及生态需求3方面计算生态用地的综合价值以识别生态源地,根据土地利用类型和夜间灯光数据构建基本生态阻力面,基于最小累积阻力模型识别潜在生态廊道,基于电路理论识别生态“夹点”,在此基础上构建了“四横三纵十组团”的武汉市生态安全格局.结果表明: 武汉市生态源地面积为2138.2 km2,占市域面积的24.9%,以水域和林地为主,呈组团形态集中分布在市域南北.生态廊道总长度为1222.42 km,其中,水生廊道566.75 km,陆生廊道为655.67 km,水生廊道贯穿市域呈十字型构架,陆生廊道呈环状分布在市域四周,整体上呈现出“四横三纵”的空间格局,生态廊道上共有生态“夹点”44处,以中心城区为核呈环状分布格局.现有保护空间基本落入生态源地范围,证明了识别框架的生态意义,能够为都市区域生态安全格局的构建提供一个量化框架,以指导相关的城市空间规划.  相似文献   

5.
We explore the population‐scaling and gross domestic product (GDP)‐scaling relationships of material and energy flow (MEF) parameters in different city types based on economic structure. Using migration‐corrected population data, we classify 233 Chinese city propers (Shiqu) as “highly industrial” (share of secondary GDP exceeds 63.9%), “highly commercial” (share of tertiary GDP exceeds 52.6%), and “mixed‐economy” (the remaining cities). We find that, first, the GDP population‐scaling factors differ in the different city types. Highly commercial and mixed‐economy cities exhibit superlinear GDP population‐scaling factors greater than 1, whereas highly industrial cities are sublinear. Second, GDP scaling better correlates with city‐wide MEF parameters in Chinese cities; these scaling relationships also show differences by city typology. Third, highly commercial cities are significantly different from others in demonstrating greater average per capita household income creation relative to per capita GDP. Further, highly industrial cities show an apparent cap in population. This also translates to lower densities in highly industrial cities compared to other types, showing a size effect on urban population density. Finally, a multiple variable regression of total household electricity showed significant and positive correlation with population, income effect, and urban form effect. With such multivariate modeling, the apparent superlinearity of household electricity use with respect to population is no longer observed. Our study enhances understanding of MEFs associated with Chinese cities and provides new insights into the patterns of scaling observed in different city types by economic structure. Results recommend dual scaling by GDP and by population for MEF parameters and suggest caution in applying universal scaling factors to all cities in a country.  相似文献   

6.

The urban fringe is areas where land use changes and develops rapidly, analyzing land use changes and driving forces in urban fringe area is of great significance for landscape pattern and ecological environment construction. This study takes the Hunhe Bird Island area of Shenyang City as the research object, uses Landsat remote sensing images from 2005 to 2019 as the basic data, and uses the land transfer matrix and landscape index method to analyze the overall landscape environment and six land types. Using government policies and statistical data to analyze the driving forces of landscape changes. The research results show that the landscape matrix had changed, the overall landscape structure had changed drastically, the ecological environment was unstable, and human interference factors had increased, and the fragmentation phenomenon had become more and more serious. Each land type has different environmental changes. Except for the relatively stable water environment, other land types have different degrees of fragmentation. The reason is that the driving force of landscape pattern changes mainly comes from the influence of human factors, which is closely related to population, economic development and government policies. Therefore, future development and protection strategies are proposed for each land type in the urban fringe area. For the overall development of urban fringe area, it is advocated to make full use of land resources, strengthen the correct judgment and forecast of urban population and economy, formulate the correct urban boundary strategy for sustainable development, avoid the ecological environment problems faced by excessive land development, and realize the “Rational expansion” of cities.

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7.
Complex changes in carbon sources and sinks caused by rapid urbanization have been observed with extensive changes in the quantity, structure, and spatial pattern of land use types. Based on the modified Carnegie-Ames-Stanford Approach model and on gray relational analysis, we analyzed the influence of land use changes on carbon sinks and emissions in Guangzhou from 2000 to 2012. The aim was to identify suitable options for built-up land expansion that would allow for minimal carbon losses. The key results were as follows: (1) Built-up land increased by 118.91% in Guangzhou city over the study period, with this expansion taking the form of concentric circles extending around the old Yuexiu district. (2) Carbon emissions over the period of analysis significantly exceeded carbon sink capabilities. The total carbon sink decreased by 30.02%, from 535.40 × 103 t to 374.6 × 103 t. Total carbon emissions increased by 1.89 times, from 13.73 × 106 t to 39.67 × 106 t; 80% of carbon emissions were derived from energy consumption. (3) There were large differences in the extent of carbon sink losses at different scales of built-up land expansion and land use change. In Guangzhou, the loss of carbon sink is small when cultivated land (though not prime farmland) and water bodies are converted to built-up land on a small scale. The loss of carbon sink is much smaller when grasslands are converted to built-up land on a large scale. However, forested land, which has excellent carbon sink functions, should not be converted. (4) Changes in carbon sinks were mainly affected by natural factors and land urbanization. Changes in carbon emissions were mainly affected by population urbanization, economic urbanization, and land urbanization. (5) To achieve “economical and intensive use of land”, “urban growth boundary” and “ecological red lines” should be determined for government policies on land use management. These factors have great significance for “increasing carbon sinks and reducing carbon emissions” in urban ecological systems.  相似文献   

8.
We analyse the current situation of the Golden eagle (Aquila chrysaetos) in the region of Galicia in NW Spain. At present, the entire Galician population (five pairs) is located within an area of about 2000 km2 in the province of Ourense. To identify high-priority areas for golden eagle conservation, we derived predictive models of habitat suitability using logistic regression and a Geographic Information System (GIS). Specifically, to model the distribution of the breeding population we considered topographic features, land use and degree of humanization, using a 10 × 10 km grid. Presence/absence of golden eagle nests was used as the dependent variable; analyses were performed both considering current nesting areas and considering old nesting areas (1960s and 70s). At the spatial scale considered, the best predictors of habitat suitability for breeding were topographical variables indicative of rugged relief. For current nesting areas the most parsimonious model included maximum altitude. We consider that the predictive models obtained may be of use for the monitoring and conservation management of the golden eagle population in this region. Conservation problems associated with habitat constraints such as food supply, availability of nesting sites, changes in land use and human disturbance are discussed.  相似文献   

9.
生境质量对城镇化的时空响应——以长春市为例   总被引:1,自引:0,他引:1  
生境质量是评价区域生态安全的重要指标,掌握其对城镇化发展的时空响应,有利于新型城镇化的深入推行。本研究基于土地利用数据,在综合利用空间分析及生态模型分析基础上,从网格尺度对长春市景观格局、生境质量及其样带进行时空特征分析,并进一步探讨生境质量在城镇化发展过程中的响应状况。结果表明: 长春市景观斑块密度、边缘密度及Shannon多样性指数低值多分布在西部平原地带,聚合度指数高值区则在市域东部及南部呈现片状格局。2000—2015年,长春市生境质量呈退化趋势且空间异质性显著,大致呈现出“东高西低”分布态势,建设用地扩张及交通基础设施建设对区域生境质量退化起到主导作用;不同样带内生境质量变化存在显著差异性,水域整体变化相对较小,而山脉、城市扩张及交通的变化频度及幅度处于较高水平。坡度及高程等自然因素基本塑造了长春市生境质量整体分布格局,而人口密度、国内生产总值、夜间灯光指数等城镇化要素与生境质量总体呈负相关关系。为缓解城镇化带来的生态压力、促进生境质量的回升,本研究提出防止大黑山脉林区滥砍乱伐、以生态手段修复生境退化地区,提升城镇建成区土地利用效率、促进城镇“精明增长”,设定丘陵地带耕地红线、加强生态基础设施建设等差异化发展策略。  相似文献   

10.
A meta-analysis of global urban land expansion   总被引:27,自引:0,他引:27  
The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km(2) from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km(2) and 12,568,000 km(2), with an estimate of 1,527,000 km(2) more likely.  相似文献   

11.
生态系统水源涵养服务作为水资源得以持续的基础和保障,正持续遭受着人类活动的干扰和影响,土地利用变化作为主要的方式之一,对水源涵养的影响广泛而且深远。运用InVEST模型模拟了闽三角城市群2015年和2030年的水源涵养情景,发现到2030年闽三角城市群区域内水源涵养量总体会下降0.24×108 m3;对比发现:土地利用变化对水源涵养的影响主要主要表现在变化面积、变化方向、作用强度以及面积补偿作用四个方面。首先面积变化方面,水源涵养量同用地类型的面积大小正相关,但二者的变化量并不正相关;其次变化方向方面,相比变化为城市生态系统和水域生态系统而言,变化为自然生态系统和农业生态系统的土地利用变化更有利于生态系统水源涵养;再次,土地利用变化对水源涵养产生作用的强度由强及弱以此为林地、其他土地、草地、农田、建设用地、水域及滩涂;最后,面积变化后的补偿作用方面,由于不同用地类型水源涵养能力和面积变化量的差异,由农田、林地、草地及其他土地面积下降导致的水源涵养量损失并不能通过建设用地、水域及滩涂用地类型面积的增加得以完全补偿。  相似文献   

12.
当前,我国城市化进程已由外延式的扩张逐步转变为内涵式发展.集约利用土地资源,构建“紧凑城市”变得越来越迫切.然而,集约利用土地意味着更少的土地资源承载更多的城市要素,人们对环境污染,特别是大气环境污染会变得越来越敏感,研究城市土地集约利用水平对大气污染的影响具有重要意义.本研究以南昌市中心城区为研究区,采用普通克里格插值法模拟6种主要大气污染物(PM2.5、PM10、SO2、NO2、CO、O3)浓度的空间分布,基于土地利用样本区,选择综合容积率、建筑密度、人口密度等16个土地集约利用水平相关变量,采用偏最小二乘回归与通径分析方法,定量分析土地集约利用水平对大气污染物的影响.结果表明: 土地集约利用水平相关变量与PM2.5和PM10的相关性最强,其次是O3和NO2,与SO2和CO的相关性最弱;不同土地利用样本区土地集约利用水平变量与6类主要大气污染物的相关性强弱依次为:居住区>教育区>商业区>工业区.土地集约利用水平越高,对大气污染物的影响越大,其中PM2.5与PM10的影响最大,其次是O3,NO2的影响较小.各土地利用样本区土地集约利用水平对大气污染物的直接影响、间接影响和综合影响基本相当,但总体而言,土地集约利用水平的直接影响大于间接影响,其中,居住区土地集约利用水平的综合影响最大,其次是商业区,最小的是教育区.本研究为土地集约利用对大气环境的影响研究提供了新的思路,为解决紧凑城市大气环境问题提供了一定的参考.  相似文献   

13.
How can one understand the increasing interest in “urban invasions”, or biological invasions in urban environments? We argue that interest in urban invasions echoes a broader evolution in how ecologists view “the city” in relation to “the natural”. Previously stark categorical distinctions between urban and natural, human and wild, city and ecology have floundered. Drawing on conceptual material and an analysis of key texts, we first show how the ecological sciences in general—and then invasion science in particular—previously had a blind spot for cities, despite a number of important historical and continental European exceptions. Then, we document the advent of an urban turn in ecology and, more recently, in invasion ecology, and how this has challenged fundamental concepts about “nativity”, “naturalness”, and human agency in nature. The urban turn necessitates more explicit and direct attention to human roles and judgements. Ecology has moved from contempt (or indifference) for cities, towards interest or even sympathy.  相似文献   

14.
城市空间形态紧凑度模型构建方法研究   总被引:6,自引:6,他引:6  
赵景柱  宋瑜  石龙宇  唐立娜 《生态学报》2011,31(21):6338-6343
我国城市空间形态的急剧变化给经济、社会、城市建设等带来诸多问题,使相对脆弱的城市生态环境承受巨大的压力,对城市可持续发展构成了一定的影响。深入了解城市景观的格局演变过程和机理,并构建适宜的城市空间形态定量化评价模型对于推进我国城市可持续发展、合理利用和保护区域生态环境具有重要的现实意义,也是我国城市发展的紧迫需求。在Thinh等提出的城市紧凑度算法的基础上,构建了一种城市空间形态定量化评价指标,即标准化紧凑度指数(normalized compactness index, NCI)。NCI将圆形区域作为标准度量单位,实现测算结果的标准化,在一定程度上避免了城市面积因素对评价结果所带来的影响,因而便于城市之间或同一城市不同时段间的城市空间形态紧凑程度的比较分析,为城市空间形态紧凑程度的定量评价提供了一种新的技术方法。  相似文献   

15.
The “Eh da”‐Initiative: more space for Biological Diversity in Cultural Landscapes The “Eh da”‐initiative is based on the principle that definite land in cultural landscapes is “available anyway” (what ?eh da“ means in German) and has the potential for ecological upgrading without relevant limitations of land use. “Eh da” could be the acronym “Ecological habitat development areas.” This land is located in open landscapes: along waysides, on uncropped plots in farmland, it could be communal lawn and other land categories. The initiative uses geodata in order to detect and quantify “Eh da”‐sites. According to an analysis based on geodata in selected landscapes “Eh da”‐land constitutes 2–6 per cent of the total area of Germany. “Eh da“‐sites are mostly narrow, longitudinal and spread like a net all over the landscape. Mainly insects and other invertebrate animals can be supported by upgrading of “Eh da”‐land. Since these sites often form corridors, they may be part of communal biodiversity protection initiatives under the perspective of ecological networks, or they may be used for distinct projects. Communication is a key element of any local initiative in which not only the ecological upgrading options, but also potential trade‐offs (like increase of agricultural pests and weeds, neophyta and pyrrolizidine containing or allergenic plants) should be discussed.  相似文献   

16.
Fine Structure of the Club Cells (Alarm Substance Cells) in the Epidermis of Astyanax mexicanus Filippi 1853 (Characinidae, Pisces) and its Cave Forms “Anoptichthys” The club cells in the epidermis of Astyanax mexicanus are of the same ultrastructure as those in other Ostariophysan fish. There are also no essential differences to be found between the club cells of epigean Astyanax mexicanus and its cave forms “Anoptichthys”. Our findings correspond to former statements in that the function of the club cells producing and releasing alarm substances has been maintained in the cave forms.  相似文献   

17.
新疆城镇化与土地资源产出效益的空间分异及其协调性   总被引:2,自引:0,他引:2  
杨宇  刘毅  董雯  李莉 《生态学报》2011,31(21):6568-6578
通过探索性空间分析以及协调发展度函数对1995-2008年新疆城镇化水平和土地资源产出效益的空间效应及两者之间的协调发展程度进行了系统分析,得出结论:(1)新疆各县市城镇化水平和土地资源产出效益在空间上均呈现明显的空间集聚。总体而言天山北坡和南疆铁路沿线是城镇化和土地资源产出效益热点相对集中的区域。(2)从协调发展度来看,整体上呈现纺锤体结构,"弱者恒弱"的马太效应难以打破,南北疆城镇呈现不同的演变轨迹。(3)将新疆所有城镇分为同步协调型、城镇化滞后型、土地效益滞后型、逐步磨合型、低级协调型五种类型,其中同步协调型城镇较少,其他类型的城镇数量较为均等。  相似文献   

18.
社会经济因素对上海市居住区植物多样性的影响   总被引:1,自引:0,他引:1  
居住区是城市地区主要的土地利用类型之一,也是城市生物的重要生境之一,在生物多样性保护中发挥着重要作用.前人研究发现,国外城市居住区的植物多样性受到社会经济水平的影响,在中国的城市管理体制下,上述结论是否成立有待证明.本研究对上海市39个居住区进行植物多样性调查,选取人口密度、房价、房龄、绿化率4个社会经济指标,利用单因素分析和偏最小二乘回归分析方法,探讨社会经济因素对上海市居住区植物多样性的影响.结果表明: 社会经济因素会影响城市居住区的植物多样性,人口密度、房价、房龄和绿化率对不同分类群的物种多样性的影响各异.其中,房龄对大多数分类群的影响效果最大,其次是人口密度、绿化率和房价.本研究证明,“奢侈效应”和“遗产效应”假说在上海城市居住区只适用于一部分植物类群.研究结果可为上海的城市植物多样性的维持、保护、管理以及城市和景观规划提供参考.  相似文献   

19.
王保盛  廖江福  祝薇  邱全毅  王琳  唐立娜 《生态学报》2019,39(12):4284-4298
以闽三角城市群2030年土地利用模拟为例,针对FULS模型邻域权重参数提出一种基于历史情景的设置方法。首先以2015年土地利用数据为基础,结合人工神经网络算法综合12个自然、社会、经济驱动因子计算各土地类型的出现概率和空间分布,然后依据对历史情景的分析,分别用马尔可夫链和分析景观格局指数的方法设定相关参数,最后用自适应惯性竞争元胞自动机模拟闽三角城市群2030年的土地利用情景。分析发现,同时间尺度各土地类型TA (Total Area)的变化量可以较好的反映其扩张强度,由强到弱依次为建设用地、水域及滩涂、其他土地、草地、林地及农田;TA变化量的无量纲值在数据意义和数据结构方面均较好地契合FLUS模型邻域权重的参数要求;结合各土地类型TA变化量和扩张强度间的相互关系来看,到2030年农田受建设用地扩张的影响最为严重,大量土地由农田、林地、草地及其他土地转变为建设用地或水域及滩涂;建设用地持续扩张,闽三角城市群空间一体化格局基本形成,其余各土地类型被进一步分离,同类型斑块更趋于独立发展。综合参数设置过程和模拟结果来看,TA变化量的无量纲值可为FLUS模型的邻域权重参数设置提供一种客观可行的方法。  相似文献   

20.
Leeches of the genus Helobdella are small brooding annelids that inhabit lakes and streams on every continent, notably in South America. The type species, H. stagnalis L. 1758, occurs in Europe and North America. Here I provide novel observations on the occurrence, morphology, and parental care patterns of the related H. californica, a taxon described in 1988, based on specimens collected in Stow Lake, Golden Gate Park, San Francisco. In 2007, the original H. californica population no longer existed, possibly due to eutrophication of this popular “duck pond”. However, in other, cleaner lakes of the Golden Gate Park dense, stable populations of H. californica were discovered. Between 2007 and 2010 adult individuals were investigated in the laboratory with respect to their pigment patterns and feeding behaviour. The leeches suck the red, haemoglobin‐rich haemolymph from insect larvae (Chironomus sp.) and other small aquatic invertebrates and feed their young attached to their ventral surface. A typical feeding episode is described and documented. In addition, a neighbour‐joining analysis was performed based on a newly acquired DNA sequence of part of the mitochondrial gene cytochrome c oxidase subunit I (CO‐I) for H. californica, combined with other, related leech species. These molecular data corroborate that the “Golden Gate leech” is a separate species and not a colour variant of H. stagnalis. Since, over the past 25 years, H. californica has only been found in the freshwater ecosystems of the Golden Gate Park, it is concluded that this rare leech is a species restricted to San Francisco. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

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