Indicators for green spaces in contrasting urban settings

Urban green spaces (GS) are essential for the well-being of the population. Several works have shown a positive correlation between the amount of GS and the household incomes in both developed and developing countries. Thus, the higher the incomes, the larger the total area covered by GS, the better the quality of these spaces, the higher the amount of private GS. Public policies seek to correct this inequality, but existing indicators, especially the amount of GS per inhabitant, do not provide enough information for effective decision-making. Our aim was to provide tools to evaluate and plan better the location and quality of GS in complex urban areas. For this we applied a set of indicators for GS at two spatial scales city-level and local-level, in order to disclose existing inequalities. The indicators considered (i) the total area of GS in relation to population and urban context, (ii) the quality of GS based on its size, shape and vegetation cover, and (iii) the spatial distribution and accessibility of GS. The proposed indicators were tested in three municipalities, belonging to the Metropolitan Area of Santiago (Chile), with different household incomes. The indicators showed large differences in terms of quantity of GS per inhabitant, vegetation cover and accessibility. The GS proved to be an effective strategy to reduce areas that lack vegetation cover. The sustainability assessments must consider how the diversity of structural attributes of GS has an impact on the well-being of urban inhabitants.     

长春城市森林绿地土壤肥力评价

以长春城市森林绿地为研究对象,测定9种土壤指标并参照全国第二次土壤普查分级标准对长春城市森林绿地土壤整体特征进行评级,采用内梅罗指数法分析长春城市森林绿地不同林型、行政区、环路土壤肥力,结合ArcG IS分析长春城市森林绿地土壤养分空间分布特征,以期对长春城市森林建设提供依据和建议。对比全国第二次土壤普查所确定的分类等级(6等级),土壤有机质平均含量(34.51 g/kg)及其空间分布(大部分区域30 g/kg)达到了2级、含量高的水平;全氮(均值1.37 g/kg)、碱解氮(均值133.04 mg/kg)、速效磷(均值38.47 mg/kg)及其空间分布均达到了3级以上水平;全钾(均值58.7 g/kg)和速效钾(均值255.85 mg/kg)及其空间分布达到1级、含量很高的水平;全磷平均含量0.51 g/kg,空间上大部分区域集中在0.4—0.6g/kg,为4级、含量中下水平。土壤pH为5.43—8.89,容重为1.11—1.62 g/cm~3。内梅罗综合肥力指数分析表明长春城市多数区域处于1.5—1.8之间,处于中等水平(4级制中排第3级)。不同林型间差异主要表现在pH、全氮、全磷和碱解氮(P0.05),不同环路间差异主要在pH、有机质和全磷(P0.05),而不同行政区间差异指标最多,为有机质、全氮、碱解氮、全磷、速效磷和pH(P0.05)。综合肥力指数显示:景观林单位附属林=农田防护林道路林,绿园区朝阳区南关区二道区宽城区,1环3=4环2环4环外。根据以上结果,可采取疏松土壤、枯枝落叶沤肥、增施氮磷有机肥而控制钾肥、种植固氮耐低磷植物等措施推进长春城市森林建设,提升城市植被生态服务功能。     

Parid foraging choices in urban habitat and their consequences for fitness

Urban environments are habitat mosaics, often with an abundance of exotic flora, and represent complex problems for foraging arboreal birds. In this study, we used compositional analysis to assess how Blue Tits Cyanistes caeruleus and Great Tits Parus major use heterogeneous urban habitat, with the aim of establishing whether breeding birds were selective in the habitat they used when foraging and how they responded to non‐native trees and shrubs. We also assessed whether they showed foraging preferences for certain plant taxa, such as oak Quercus, that are important to their breeding performance in native woodland. Additionally, we used mixed models to assess the impact of these different habitat types on breeding success (expressed as mean nestling mass). Blue Tits foraged significantly more in native than non‐native deciduous trees during incubation and when feeding fledglings, and significantly more in deciduous than evergreen plants throughout the breeding season. Great Tits used deciduous trees more than expected by chance when feeding nestlings, and a positive relationship was found between the availability of deciduous trees and mean nestling mass. Overall, the breeding performance of both species was poor and highly variable. Positive relationships were found between mean nestling mass and the abundance of Quercus for Great Tits, but not for Blue Tits. Our study shows the importance of native vegetation in the complex habitat matrix found in urban environments. The capacity of some, but not all, species to locate and benefit from isolated patches of native trees suggests that species vary in their response to urbanization and this has implications for urban ecosystem function.     

Complexity of species conservation in managed habitats: interaction betweenMaculinea butterflies and their ant hosts

Europe's five species ofMaculinea butterfly are examples of endangered species adapted to live in traditional, cultural landscapes. All are threatened with extinction in Western Europe because of recent changes in land use. This is illustrated by an historical account of the extinction of the BritishMaculinea arion populations, despite many conservation attempts. It is shown how the failures proved to be due to ignorance of the key factor forM. arion, its specialization on a single ant host,Myrmica sabuleti. A brief account is given of research that shows how each of the five species is similarly dependent upon a separate hostMyrmica ant species and how each has an interesting and rare specific parasitoid. Steps for the practical conservation of existingMaculinea populations including the obligation, under the Bern Convention, to re-establish nationally extinct species are outlined. The procedure and problems involved in re-establishment are illustrated with reference to the successful programme forM. arion in Britain. The best way of ensuring robust populations ofMaculinea butterflies is to manage habitats to optimize the density and distribution of the required species ofMyrmica host and, secondarily, the distribution of the larval food plant. The value of single species conservation in cultural habitats is discussed. It is concluded that this is possible to achieve and that other rare organisms also often benefit, but only when conservation measures are based on the results of detailed autecological research.     

城市绿地的生态环境效应研究进展

工业化的快速发展和城市化进程的加剧,使得城市生态环境的破坏和污染愈来愈严重,加速了城市的“生态环境危机”.城市绿地能够通过植被的光合作用、吸收作用、隔离阻挡作用、蒸腾以及蒸散作用改善城市的生态环境.目前研究主要集中在降温、增湿、固碳释氧、降噪、抗污染、生物多样性保护等6个方面.关于城区绿地对6种生态环境要素的改善程度、影响范围、机理问题以及不同植被种类生态环境效应的差异情况等,国内外学者都进行了大量详细的研究.基于传统实地观测数据进行城市绿地的生态环境效应研究是目前主要使用的研究方法,部分学者开始使用遥感技术手段研究城区绿地的降温增湿效应.在总结和分析前人研究成果的基础上,从研究内容的不同着手,主要总结并系统评估了目前关于城市绿地6种生态环境效应的研究,为今后相关研究提供参考.     

半湿润地区城市绿地灌木的截留集水功能及其影响因素

在半湿润地区,创新节水型城市绿地建设模式,实现绿地由耗水型向节水型转变,是学术界关注的热点问题。通过模拟降雨的方法,对半湿润地区城市绿地中的金叶女贞、大叶黄杨、小叶黄杨、红叶石楠、龙柏和侧柏等6种灌木的截留集水功能及其影响因素进行研究。结果表明: 冠层截留和茎流集水是水文过程的两个不同阶段,常绿灌木冠层截留大,但其茎流集水差;随着雨强增大,所有灌木的穿透雨率和茎流率都明显增加,但截留率却相对减少;穿透雨率表现为阔叶灌木显著大于针叶灌木,茎流率趋势与之相同,而截留率则相反。冠层投影中心区域穿透雨率最小,随着与冠层投影中心距离的加大,叶面积指数降低,穿透雨率也呈逐步减少趋势;当雨强为小雨时,冠层投影中心的穿透雨率小,即截留率和茎流率大,当雨强为大雨时,冠层投影中心的穿透雨率大,即截留率和茎流率小;随着雨强增大,冠层外围穿透雨率增大,漏斗形截留集水系统呈缩小趋势。雨强和叶面积指数是显著影响灌木截留集水功能的重要因素;半湿润地区城市绿地在林下配置阔叶灌木更有利于截留集水。     

北京公园绿地夏季温湿效应

选取北京典型的城市园林绿地--元大都城垣遗址公园北段不同覆盖率的乔-灌-草、乔-草型复层结构的公园绿地作为研究对象,以草坪型绿地作为对照,从水平和立体空间两个角度进行测试,研究局部绿地的覆盖率、复层结构对环境的温湿效应.结果表明:在夏季高温时段,绿地的温度随覆盖率的增加而降低,当覆盖率达到或高于60%时,其绿地才具有明显的降温增湿效果;覆盖率较高的乔-灌-草复合型绿地给环境带来的温湿度的空间影响范围较大,乔-灌-草复合型绿地的降温增湿效应好于草坪.合理的绿化结构及植物配置能使城市园林绿地较好地发挥其夏季的降温增湿效应,有利于改善城市热环境、减缓城市热岛效应.     

Persistence of species in a fragmented urban landscape: the importance of dispersal ability and habitat availability for grassland butterflies

Some species cope with, and survive in, urban areas better than others.From a conservation viewpoint it is important to understand why some species arerare or are excluded in the urban landscape, in order that we might take actionto conserve and restore species. Two ecological factors that might explain thedistribution and abundance of butterfly species in the urban landscape aredispersal ability and the availability of suitable habitat. The influence ofthese factors was assessed by examining the distribution and genetic structureof four grassland butterfly species in the West Midlands conurbation, UK. Thefour species differ in their distribution and abundance, mobility and habitatspecificity. No significant fit to the isolation-by-distance model was found forany of the study species at this spatial scale. MeanF _ST values revealed a non-significant level ofpopulation structuring for two species, Pieris napi (L.)and Maniola jurtina (L.), but moderate and significantpopulation differentiation for Pyronia tithonus (L.) andCoenonympha pamphilus (L.). Results suggest that thesespecies are limited more by the availability of suitable habitat than by theirability to move among habitat patches. Conservation strategies for thesegrassland species should initially focus on the creation and appropriatemanagement of suitable habitat. More sedentary species that have already beenexcluded from the conurbation may require a more complex strategy for theirsuccessful restoration.     

城市绿地动物声景的时空特征及其驱动因素

动物群落是构成城市绿地生态系统的关键要素,声景作为野生动物重要的生态信息,掌握其时空变化及其影响因素,对于指导城市绿地景观设计与生物多样性保护具有重要意义。本文以Web of Science数据库的核心合集2005–2022年收录的67篇研究文献为对象,综合梳理与分析了城市绿地动物声景的时空模式及其驱动因素。城市绿地动物声景在空间上表现出环境空间梯度和植被空间结构的差异,动物声音多样性随海拔、纬度、城市化程度的降低以及植被类型和高度的增加呈现升高趋势。时间尺度呈现出昼夜、季节和年度变化差异,表现为鸟类在黎明和黄昏合唱、昆虫和两栖动物在夜间鸣叫以及季节性和年度性发声规律等。影响城市动物声景模式的因素主要包括植被、环境、人为干扰和动物自身驱动等。动物声景作为当前声景生态学研究的热点之一,面临大时空尺度演变规律研究不足、动物声景分析有限等挑战,建议未来着重开展多时空尺度变化规律研究、创新动物声景分析方法、定量解析影响因素及其响应机制、建立全球动物声景数据库等。     

Valuing urban green spaces in mitigating climate change: A city‐wide estimate of aboveground carbon stored in urban green spaces of China's Capital

Urban green spaces provide manifold environmental benefits and promote human well‐being. Unfortunately, these services are largely undervalued, and the potential of urban areas themselves to mitigate future climate change has received little attention. In this study, we quantified and mapped city‐wide aboveground carbon storage of urban green spaces in China's capital, Beijing, using field survey data of diameter at breast height (DBH) and tree height from 326 field survey plots, combined with satellite‐derived vegetation index at a fine resolution of 6 m. We estimated the total amount of carbon stored in the urban green spaces to be 956.3 Gg (1 Gg = 10⁹ g) in 2014. There existed great spatial heterogeneity in vegetation carbon density varying from 0 to 68.1 Mg C ha^‐1, with an average density of 7.8 Mg C ha^?1. As expected, carbon density tended to decrease with urban development intensity (UDI). Likely being affected by vegetation cover proportion and configuration of green space patches, large differences were presented between the 95th and 5th quantile carbon density for each UDI bin, showing great potential for carbon sequestration. However, the interquartile range of carbon density narrowed drastically when UDI reached 60%, signifying a threshold for greatly reduced carbon sequestration potentials for higher UDI. These findings suggested that urban green spaces have great potential to make contribution to mitigating against future climate change if we plan and design urban green spaces following the trajectory of high carbon density, but we should be aware that such potential will be very limited when the urban development reaches certain intensity threshold.     

北京城市绿地调蓄雨水径流功能及其价值评估

随着城市化进程的加快,城区不透水面积急剧增加,改变了城市自然水循环。充分认识与发挥城市绿地调蓄雨水径流的积极作用,对于城市生态环境的改善和绿地资源的建设管理具有重要意义。本文以2009年北京城市园林绿地调查数据为基础,采用径流系数法和影子价格法评估了绿地调蓄雨水径流的功能及其价值。结果表明：2009年北京城市绿地生态系统调蓄雨水径流1.54亿m3,单位面积绿地调蓄雨水径流2494 m3/hm2;绿地年调蓄雨水径流价值13.44亿元,约合2.18万元/hm2;不同区县绿地调蓄雨水功能主要受其面积影响,朝阳区绿地调蓄雨水径流及其价值量最高,其次为海淀区、顺义区、丰台区区和通州区绿地,而密云县、怀柔区和门头沟区绿地调蓄雨水径流能力及其价值较低。本研究对于认识北京城市绿地的功能与价值、促进城市绿地的科学管理和建设维护具有一定的指导意义。     

Woody plant composition and diversity of urban green spaces in Istanbul,Turkey

Abstract

The high urbanization rate of Istanbul in response to rapid population decreased the size and amount of green spaces. Thereby, every green space types are of vital importance in terms of conservation of urban biodiversity. In this study, it was aimed to compare woody species composition of main green space types consist of artificial and natural sites. Botanical gardens had the highest diversity followed by gardens. Residential areas showed to be important in terms of shrub (52%) and evergreen species (58%), which are mostly exotics (71%). The ratio of the invasive plants in the composition was higher in parks, which contain highway greenings and public gardens. Since the most tree species used in public green areas of Istanbul were mostly same with the species used in European cities, all of the green space categories having varied composition must be considered as interconnected habitat patches in urban planning.     

北京城市绿地的蒸腾降温功能及其经济价值评估

尽管已有大量研究证实,城市绿地具有明显降温作用,但是从生态经济学角度定量评估城市绿地降温功能及其价值的研究不多.以夏季高温热害显著的北京建成区为研究区,在前人多项绿地降温功能实测结果基础上,利用第七次园林绿地资源调查数据,定量评估了城市绿地夏季蒸腾降温的功能及其价值.结果表明:北京建成区6.1万hm2绿地每年夏季蒸腾吸热可达4.61×1015 J,平均每公顷绿地每天吸热8.4×108 J,相当于10台1000瓦空调的降温作用.参照居民用电价格,建成区绿地夏季降温价值为6.4亿元,单位绿地降温价值约1.05元/m2.此外,不同绿地类型和区县绿地的降温功能差异较大,主要受绿地面积和组成结构的影响.     

城市绿地和建筑格局影响热环境的模拟研究

景观类型和格局能够影响城市热环境,但是在不同小区域背景下,它们的贡献差异尚缺少定量研究。将实地监测与数值模拟技术相结合,对北京市典型景观的风速场与温度场进行模拟研究,分析天空开阔度、绿地面积与风速、地表温度之间的关系。在此基础上,探讨绿地形态与绿地温度及地表温度的关系,同时设计多种典型的城市绿地、建筑格局在计算机中进行模拟,揭示不同绿地、建筑景观配置下热环境的影响因素。结果表明：（1）天空开阔度和风速是影响城市小区域热环境的重要因素,天空开阔度与地表温度显著负相关,高风速会明显降低地表温度;（2）绿地面积和形态是影响区域地表温度与气温的重要因素,占比10%-50%的绿地降温强度为1.4-2.2℃,面积越大、形态越复杂,降温效应越明显,分散的绿地降温效应优于集中式绿地;（3）迎风向呈两端低中间高的建筑分布可显著改善热环境,较其它格局气温约低1.6℃。研究结果对于指导城市景观设计改善城市热环境具有一定的参考价值。     

上海城市绿地夏季降温效应及其影响因素

城市绿地在夏季高温时具有明显降温作用,但在不同地区降温效果及其影响因子存在一定差异。以上海市为例,基于高分影像和实地观测,调查分析了18个典型样地夏季降温效应及其关键影响因子。结果发现：上海城市绿地夏季日均降温1.17-5.60℃,其中67%观测样地降温幅度低于平均值（2.51℃）;绿地降温幅度与对照点的环境温度显著正相关,当外界环境温度低于26℃时,城市绿地降温效应不明显;此外,城市绿地覆被格局对其降温效应有明显影响,当绿地乔木密度增加5%、叶面积指数增大1或者水面比例增加20%时,可使夏季绿地降温率分别提高1.73%、1.66%和1.18%。因此,在全球气候变暖背景下,优化提升上海城市绿地覆被格局可有效提升夏季绿地降温效应。     

上海园林绿地植被结构与温湿度关系浅析

通过对上海市区园林绿地29个样方的植被结构与微环境及土壤湿度、温度的调查,结果表明,绿地具有明显的增湿降温作用,影响这一作用的主要因素是绿地的乔木植物盖度。土壤湿度与草本植物盖度呈极显著正相关。土壤湿度、温度在一定区间内,呈极显著正相关。复杂完善的植被结构对防止土壤水分蒸发具有较好的效果。     

Corridors and barriers in biodiversity conservation: a novel resource-based habitat perspective for butterflies

Habitat loss and fragmentation, exacerbated by projected climate change, present the greatest threats to preservation of global biodiversity. As increasing habitat fragmentation and isolation of residual fragments exceeds the dispersal capacity of species, there is the growing need to address connectivity to maintain diversity. Traditionally, habitat corridors have been proposed as a solution. But, the concept of corridors (barriers) is poorly understood; typically they are defined as linear habitats linking up habitat patchwork, and are advocated without a detailed understanding of the elements making up species’ habitats and the cost-effectiveness of alternative solutions. Yet, landscapes comprise an enormous range of ‘linear’ structures that can function in different ways to promote species’ persistence and diversity. In this review, a functional definition of corridor (barrier) is developed to give prominence to connectivity as opposed to ad hoc structures purported to advance connectivity. In developing the concept, urgency to accommodate environmental changes compels a growing emphasis on organism diversity rather than a preoccupation with single species conservation. The review, in focusing on butterflies to address the issue of corridors for patchwork connectivity, draws attention to fundamental divisions among organisms in any taxon: generalists and specialists. Both groups benefit from large patches as these necessarily house species with specialist resources as well as generalists with very different resource types. But, generalists and specialists require very different solutions for connectivity, from short-range habitat corridors and gateways for specialists to habitat and resource stepping stones (nodes, surfaces) for generalists. Connectivity over extensive areas is most critical for moderate generalists and their conservation requires emphasis being placed on space–time resource heterogeneity; landscape features, of whatever dimensionality and structure, provide a vital framework for developing the variety of suitable conditions and resources for enhancing their diversity.     

Habitat preference and habitat exploration in two species of satyrine butterflies

We compared the habitat preference and the mobility of different populations of primarily forest living, satyrine butterflies by observing them in a manipulated environment, containing different habitat types inside a large outdoor cage. The cage was 30 m long and divided into three parts. Each end of the cage contained a shady habitat, made to be similar to the floor of a forest with sunlit spots. In between these shady parts, there was a 14 m long open part, like a glade or a meadow. We performed two studies in the cage. In the first study, we compared a population of a species with very restricted distribution in Sweden, Lopinga achine , and a population of a widely distributed and expanding species, Pararge aegeria . We found that the two species had similar habitat preferences in the cage, but that L. achine had a lower rate of dispersal from one shady part of the cage to the other. In the second study, we compared two populations of P. aegeria , a Swedish forest living population and a Madeiran population inhabiting a fairly open habitat. We found that, although individuals of the Swedish population avoided staying in the open, middle part of the cage, they dispersed between the shady parts of the cage at a higher rate than individuals of the Madeiran population. We argue that studies of the kind we performed can serve the purpose of testing hypotheses about habitat preference and mobility that derive from other field work or from information about distribution patterns.