Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chiuensis, Sophora japonica Ailanthus altissima, Syringa oblata and Prunus persica, had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicns and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM30 （particulate matter less than 10 μm in aerodynamic diameter; 98.4%） and PM2.5 （particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%） which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO2, CaCO3, CaMg（CO3）2, NaCI and 2CASO4. H2O, SiO2. CaCO3 and CaMg（CO3）2 mainly came from resuspension of road dust. 2CaSO4. H2O was produced by the reaction between CaCO3 derived from earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt.

Review of Researches on the Protection of Urban Plant Diversity

With the accelerating urbanization and population explosion, urban ecological environment has been seriously damaged, ecosystem has become unbalanced, and plant diversity has reduced constantly. This paper analyzed domestic and foreign literatures on the protection of urban plant diversity in recent years, summarized the previous researches on the protection of urban plant diversity, and major measures for protecting urban plant diversity.

A fine-scale assessment of the ecosystem service-disservice dichotomy in the context of urban ecosystems affected by alien plant invasions

Background: Natural resources within and around urban landscapes are under increasing pressure from ongoing urbanisation, and management efforts aimed at ensuring the sustainable provision of ecosystem services(ES) are an important response. Given the limited resources available for assessing urban ES in many cities, practical approaches for integrating ES in decision-making process are needed.Methods: We apply remote sensing techniques(integrating LiDAR data with high-resolution multispectral imagery)and combined these with supplementary spatial data to develop a replicable approach for assessing the role of urban vegetation(including invasive alien plants) in providing ES and ecosystem disservices(EDS). We identify areas denoting potential management trade-offs based on the spatial distribution of ES and EDS using a local-scale case study in the city of Cape Town, South Africa. Situated within a global biodiversity hotspot, Cape Town must contend with widespread invasions of alien plants(especially trees and shrubs) along with complex socio-political challenges. This represents a useful system to examine the challenges in managing ES and EDS in the context of urban plant invasions.Results: Areas of high ES provision(for example carbon sequestration, shade and visual amenity) are characterized by the presence of large trees. However, many of these areas also result in numerous EDS due to invasions of alien trees and shrubs – particularly along rivers, in wetlands and along the urban edge where tall alien trees have established and spread into the natural vegetation(for example increased water consumption, increased fire risk and reduced soil quality). This suggests significant trade-offs regarding the management of species and the ES and EDS they provide.Conclusions: The approach applied here can be used to provide recommendations and to guide city planners and managers to fine-tune management interventions at local scales to maximise the provision of ES.

Diversity Analysis on the Plant Communities of Urban Park Green Space in Wuhan

In order to systematically study the diversity of plant communities in park green space,78 plant communities of 10 representative parks in Wuhan City were investigated.The total 449 species belonging to 275 genera and 112 families were found in this investigation.The communities were divided into 35 dominant-species,13 life-forms and 6 vegetation-forms.The community structures and the composition of dominant species were also studied.The results showed that the shortages of the low diversity,high proportion of exotic species and simple community structures appeared in plant community of park green space in Wuhan City.It is proposed that species,especially native ones,should be abundant to keep a high level species diversity.At the same time,more simulated native communities should be utilized to build the natural,multi-layers,bright local vegetation characteristics landscape of urban parks.

Influence of night-time light pollution on the photosynthesis and physiological characteristics of the urban plants Euonymus japonicus and Rosa hybrida

Background Night-time light pollution(NLP),which breaks the natural cycle of day and night,has become a new threat to urban ecosystems.Plants are the main component of urban ecosystems and play an irreplaceable role in maintaining urban ecological balance.The effects of NLP with various radiation sources,including green,white,blue and red light provided by light-emitting diodes,on urban plants,Euonymus japonicus and Rosa hybrida,were examined in a block field experiment.Results NLP caused photoinhibition and oxidative stress in plants,and the extent of the deleterious effects varied with the spectral distribution of artificial light sources and species.Both E.japonicus and R.hybrida were more sensitive to blue and red light,which reduced the pigment concentration,net photosynthetic rate,stomatal limit value,effective quantum yield,apparent electron transfer rate and photochemical quenching coefficient,and markedly increased the malondialdehyde content and total antioxidant capacity.However,those negative effects under white light were only present in E.japonicus and not in R.hybrida.Furthermore,blue and red light significantly decreased the stomatal conductance of E.japonicus.In contrast,green light had no significant effect on the above indices for both species.All spectra did not significantly change the sugars and starch contents for either species.Conclusions Considering that the spectral distribution of artificial light at night in cities has great heterogeneity and that its effect varies with plant species,it is important to arrange tree species with NLP tolerance and install appropriate light sources in urban areas based on the corresponding physiological responses and adaptation of urban trees.

Analysis of Plant Configuration in Urban Landscape of Xianning City with the Beauty of Naturalness and Harmony

With the analysis of the natural geology, greening status and green plant resources in Xianning City, urban greening status of Xianning City is analyzed as a whole, the important role of plants in urban landscape is elaborated, and the relationship among regional environment, plant configuration and landscape aesthetics is proposed. The aesthetic features are interpreted through the growing habits and individual ornamental features of landscape plants. Landscape beauty presented by plants is emphasized through the aspects of thematic beauty, artistic beauty, composition and rhythm. In the respect of configuration principles of landscape plants, principles of natural, regular and combined configurations are highlighted. The discussion of rational thinking upon plant configuration in urban greening is discussed so as to improve urban ecological environment, save construction investment, and enhance the artistic taste and ornamental value of urban landscape.

Impact of urbanization on plant diversity: A case study in built-up areas of Beijing

Urbanization is developing rapidly in the world, which seriously changes the habitat of organisms and has clearly a negative effect on biodiversity. Preservation of biodiversity is crucial in urban planning and management, which is also an important symbol for the level of greening. Problems such as scarcity of urban green space and plant species have become obstacles to the establishment of ecological friendly cities. However, coexistence of nature and modernization, as well the coordination of economic development and biodiversity, are goals that people are seeking. We have taken the builtup areas of Beijing as a study case and discussed the impacts of urbanization on plant diversity, with the support of fieldwork and SPOT remote sensing data. The results are as follows： 1） in the process of urbanization, exotic plants have been widely introduced, which has affected species composition and the proportion of native plants; it is clear that artificial green spaces always will have a lower level of plant diversity than natural green spaces; 2） functional differences of green space types partially decide their species abundance, so that plant diversity in greenbelts and streets is generally lower than in parks; 3） the spatial variety of plant diversity contributes much to the imbalance of district de- velopment and the planning of different functional zones; this variation is embodied in different ring-belts and directions; 4） habitat fragmentation also affects plant diversity to a great extent; there is a significant positive correlation between high fragmentation and low plant diversity. According our results, some suggestions are proposed, which would be suitable for the preservation of plant di- versity and ecological improvement during urbanization.

Landscape pattern and its effect on ecosystem functions in Seoul Metropolitan area:Urban ecology on distribution of the naturalized plant species

During land transformation process in the human history, naturalized plants were introduced to several land use patterns by the different ways of plant itself. Including some naturalized plants that had been contribute to land restoration, many naturalized plants have been invaded to original habitat or landscape for native plants. Once the plants were colonized, they extend their area and population size. Urban developed areas often give an important role of source habitat for naturalized plants and expanding their population size. In recent, this situation is appearing as one of environmental problems about the urban landscape management controlling the naturalized plants that invaded in the developed area and conserving the native vegetation. This paper is focusing on relationships between distribution of habitat of naturalized plants and landscape patch in urban area in Seoul. Gangdong-Gu, one of the administrative areas in Seoul was selected for this study. We examined the recent land use change using LANDSAT TM data and spreading of the representative naturalized plants (Robinia pseudoacacia and Eupatorium rugosum) by Seoul Biotope Mapping Project and field survey in 1999. As a result, these two species were often occurred in the same habitat and distributed in forest edge disturbed by man. Their distribution patterns were related to landscape indices (patch size and shape) in the forest edge.

Application of Landscape Plants in the Huaxi National Urban Wetland Park

The current situation of plants in Shilihe Beach of the Huaxi National Urban Wetland Park was investigated and analyzed. The results show that there are about 181 species of landscape plants in this park, of which arbors and shrubs are dominant. Various species of plants grow differently because of different types of artificial maintenance. The overall partition of the wetland park dose not follow the features of a river-type wetland and is not clear. In this park, the planting area of hygrophyte is far less than that of terrestrial plants. As a result, the wetland park is evolving into a public garden. It is suggested that the overall design of the park should be conducted in accordance with site characteristics and resources, and the park should be developed and built reasonably based on the principle that the ecology is a priority.

Accumulation and migration of elements-pollutants in “soil-plant” system within urban territory

In the urbanized territory (the Irkutsk city), the content of sulfur and heavy metals (lead, cadmium, copper, zinc) in soil profile horizons and leaves (needles) arboreal plants were studied. High accumulation of polluting elements in pine and larch needles, birch and poplar leaves, as well as in all genetic horizons of the city soils was shown. There were revealed elements disbalance in city trees assimilation organs showing in the increase of the polluting elements quota with the parallel decrease of the quota of nitrogen, phosphorus, calcium, magnesium, potassium, manganese. Pollutants concentration in trees needles (leaves) was shown to be closely related to their content in soil horizons. The results speak in favor of high migration ability of polluting elements in soil profile and about possibility their entrance in trees root system and further to assimilation organs from all city soils horizons. It can be concluded that data on accumulation and migration of polluting elements in soils and arboreal trees assimilation organs contribute to adequate assessment of technogenic load on urban ecosystems.

Do Plants Have a Choice of Traits to Be Modulated? Evidence from an Invasive Plant <i>Mikania micrantha</i>Kunth in Different Urban Environments

The successful establishment of an invasive plant in a novel environment has been attributed to the phenotypic plasticity of plant traits, with most studies focussing on vegetative trait plasticity in either experimental and/or natural habitat conditions. This study explores the role of phenotypic plasticity, in both vegetative and reproductive traits, of an invasive plant Mikania micrantha growing as a ground cover in diverse urban areas in the city of Kolkata, India. Quadrat based plant and soil sampling was conducted in three habitat types, namely roadsides, natural areas and abandoned plots, from four regions within the city. The above ground biomass and fitness related vegetative and seed traits were estimated from the plant samples whereas soil macro-and micro-nutrients as well as soil health (in terms of organic carbon and microbial biomass carbon) were estimated from the soil samples. Habitat-specific selection of traits in M. micrantha was observed in this study. In roadside population which has more chances of long distance dispersal, the excessive production of reproductive biomass as a compensatory response to the low germination ability of the seeds was evident. In natural areas which are more prone to anthropogenic disturbance and where the plant has greater chances of local spread, modulation of both vegetative (higher SLA) and reproductive traits (lighter seeds with faster germination ability) helped the plant to maintain its population. In abandoned plots where there was more number of associated species, the longer span of germination and increased population height ensured the survivability of M. micrantha in the community. Thus, a continuous monitoring program to check for M. micrantha growth should be prioritized in urban areas due to its immense trait plasticity in different habitat conditions where uncontrolled growth can lead to its establishment and spread, thereby making its control more difficult.

Investigation of Vertical Planting in Urban Districts of Chongqing Municipality

Through investigating types,plant application,slope materials,soil,planting trough,auxiliary climbing facilities,and application of new technologies in vertical planting of urban districts in Chongqing Municipality,characteristics and existing problems of its vertical planting were analyzed,and corresponding suggestions given to provide references for vertical planting of mountainous cities.

城市公园植物景观引鸟设计方法研究

城市公园作为生态系统的重要组成部分,承担着生物多样性的责任。其中,鸟类在城市公园生态平衡中发挥关键作用,城市公园能为市民提供良好的观鸟体验。因此,研究如何通过植物景观设计来吸引和保护城市公园中的鸟类,具有重要的学术价值和实践意义。文章从鸟类对园林景观的重要性视角出发,从鸟类与植物的联系、优秀案例分析、引鸟区域选址、植物景观、食物来源入手,总结前人的研究成果,提出吸引和保护鸟类在城市公园中栖息的具体方法,从而丰富城市生物多样性,促进城市公园可持续发展,给予市民亲近自然的机会,形成人与鸟类友好发展的城市植物景观。

龙岩市新罗区城市绿地外来入侵植物风险评估

龙岩市新罗区作为闽西地区的政治、经济及文化中心,随着城市化进程的加快,与周边城市人员、货物往来密切,使得外来入侵植物侵入本地,生物安全遭受严重威胁。本研究旨在全面掌握龙岩市新罗区城市绿地外来入侵植物的现状,评估该地区外来入侵植物风险认知与应对能力,以制定有效的防治策略和科学管理体系。通过实地调查、查阅相关文献资料和运用样方法收集新罗区外来入侵植物情况并构建入侵风险评估体系,采用DPSIR模型结合层次分析法(AHP)确定评价指标权重,对外来植物的入侵驱动力、对本地环境适应性、本地分布情况、对本地影响、响应措施进行综合评估,并根据等级划分标准和风险值将外来入侵植物划分为3个入侵等级(Ⅰ~Ⅲ级)。结果表明:新罗区城市绿地共有65种外来入侵植物,隶属22科52属,其中菊科(Asteroideae)植物种数最多,占比为29.23%,其次是苋科(Amaranthaceae, 12.31%)和大戟科(Euphorbiaceae, 9.23%);生活型共有5种,一年生草本植物最多,共有32种,占比为49.23%;从地理来源来看,美洲是主要来源地,共有48种,占总数的73.85%;分析入侵途径发现,无意引入的植物最多,共35种,占总种数的53.85%;根据入侵现状评估结果,高风险入侵植物(Ⅲ级)有16种、中风险(Ⅱ级)18种、低风险(Ⅰ级)31种。表明新罗区城市绿地外来入侵植物种类较多,但入侵风险等级相对不高,多数处于中低风险(Ⅱ、Ⅲ级)。建议根据风险等级对危害程度最大的白花鬼针草(Bidens alba)和小蓬草(Erigeron canadensis)进行重点防控。

Landscape Effect Assessment of the Greening Mode around Overpasses in the Urban Area of Kunming City

Based on investigating the present greening situation of 18 overpasses in the urban area of Kunming City,4 typical plant furnishing modes for overpass were concluded,that is,Type Ⅰ,which was the multi-layered plant disposition pattern composed of all arbor,shrub and herbaceous plant species;TypeⅡ,which was mainly composed of shrub and herbaceous species with a 2-layered structure;Type Ⅲ was the turf grass pattern with sparsely disposed trees;Type Ⅳ,which was the simple groundcover greening pattern.1 or 2 typical overpasses from each type were sampled separately for evaluating the landscape effects of the typical green space around each type of overpass by adopting AHP model,and the results showed that the evaluated landscape effect of Type Ⅰ was 'good',that of Type Ⅱ was 'moderate',that of Type Ⅲ was 'moderate to good',and that of Type Ⅳ was 'poor'.

Effects of Urbanization,Soil Property and Vegetation Configuration on Soil Infiltration of Urban Forest in Changchun,Northeast China

Urban forest soil infiltration, affected by various factors, is closely related with surface runoff. This paper studied the effect of urban forest types, vegetation configuration and soil properties on soil infiltration. In our study, 191 typical plots were sampled in Changchun City, China to investigate the soil infiltration characteristics of urban forest and its influencing factors. Our results showed that the steady infiltration rates of urban forest soil were highly variable. High variations in the final infiltration rates were observed for different vegetation patterns and compaction degrees. Trees with shrubs and grasses had the highest infiltration rate and trees with bare land had the lowest infiltration rate. In addition, our results showed that the soil infiltration rate decreased with an increase in the bulk density and with a reduction in the soil organic matter content and non-capillary porosity. The soil infiltration rate also had significantly positive relationships with the total porosity and saturated soil water content. Urban soil compaction contributed to low soil infiltration rates. To increase the infiltration rate and water storage volume of urban forest soil, proper techniques to minimize and mitigate soil compaction should be used. These findings can provide useful information for urban planners about how to maximize the water volume of urban forest soil and decrease urban instantaneous flooding.

Application of Vertical Greening as a New Model of Expanding Urban Green Spaces

Vertical greening is a new pattern of expanding urban green spaces. Based on the concept of vertical greening, several approaches and available patterns were introduced for the vertical greening of urban spaces. Moreover, the mostly-applied vertical greening plants in China and their value were given to provide a new thought for urban greening.

Conservation Planning of Plant Diversity in Jinghong City of Xishuangbanna

General situation of Jinghong City was introduced in this study.Based on analyzing its vegetation components,species diversity,rare and endangered species,alien species,plant resources,7 biodiversity conservation contents were planned,including focusing on the construction and management of nature reserves,constructing forest park and developing science popularization engineering,establishing the area of banning hunting(picking) wild species and connection corridors,constructing wild elephant park into a zoo,promoting the role of urban parks in protecting biodiversity,devoting more in protecting rare and endangered species,preventing the danger of invasive species.4 countermeasures for applying biodiversity in urban green spaces were proposed,specifically,creating urban garden plant community by simulating natural ones to form urban plant ecosystem,determining species cardinal of urban garden plants to protect and develop species diversity,applying both local and alien plants to create diversified landscapes,introducing,domesticating or culturing new garden plants to enrich the diversity of garden plants.Also 3 countermeasures for protecting biodiversity in urban green spaces were put forward,that is,joint development of rural economy and biodiversity protection around cities,protecting species and comprehensively renovating habitats,fully utilizing ex-situ conservation to protect biodiversity.

Exotic and invasive species compromise the seed bank and seed rain dynamics in forests undergoing restoration at urban regions

The control of exotic and invasive species in areas undergoing recovery is a challenge for ecological restoration and this problem may be even greater in urbanized areas. This study evaluated the seed bank and seed rain of a 5-year-old riparian forest located at the metropolitan region of Belo Horizonte in southeast Brazil, and verified changes over time in the abundance and species richness and whether planted species already were providing propagules to the site. At the forest, fifteen parcels of 100 m2 were distributed randomly and soil samples were collected thrice (October 2011, March 2012 and July 2012) to evaluate the seed bank. Seed traps were installed in nine parcels to collect propagules over 1 year. Propagules were segregated and germinate at greenhouse. Species richness and abundance were estimated, and variance and similarity were quantified. In total, 86 species were recorded in the seed banks, 41.9% natives and 33.7% exotics, with the predominance of herbs (87.2%) and only 7% of trees. Species classified as weeds amounted to 52.3%. In the seed rain 642 seedlings germinated but they belonged to only 10 species, half of them were exotics. Regarding life forms, half of the species were arboreal and dominated the samples, highlighting the exotic species Melia azedarach. The species richness of the seed bank did not differ by season, unlike the seed rain which varied significantly by month. Seed bank and seed rain species had a very low floristic similarity with the list of planted species, suggesting that few planted trees had dispersed or were stocking propagules. Many non-planted species were recorded, mostly exotics and/or invasive that were probably derived from the surrounding urban matrix. These might interrupt the successional dynamics of the restoration forest and compromise the restoration process in the medium and long-terms. Our results highlight: (1) the importance of monitoring areas undergoing restoration; (2) that restoration methods and management actions directed to control exotic and invasive species are particularly important for sites in urban regions; and (3) the relevance of conserving forest fragments as sources of propagules for nearby areas.

Analysis of the State of Woody Plants in the City of Nukus (Streets of Ernazar Alakoz)

This article observed seven species of Fraxinus excelsior L., Fraxinus pensylvanica March., Salix alba L., Populus alba L., Juniperus communis L., Catalpa bignonioides Walt., Ulmus densa Litv for seasonal growth. The Republic of Karakalpakstan is located in the North-West of Uzbekistan, covers 166,600 km2 (28%), and is the largest in terms of territory by region. The study of woody plants in the flora of Karakalpakstan is an important aspect of the convention on biological diversity. The species composition of the natural flora of Karakalpakstan is quite poor in ornamental plants, especially evergreens, suitable for gardening. At the same time, the biodiversity of these plants in Nukus and the factors contributing to them were analyzed. Relevance of the study: Creating an environmentally friendly environment in cities is possible by optimizing intra-urban tree plantations that perform forming, improving and regulating functions in the environment. The effectiveness of green spaces mainly depends on the range of trees and shrubs and their correct use in accordance with biological characteristics, environmental requirements and decorative qualities. The degree of impact of plantings on the environment also depends on the type, age and physiological characteristics of plants [1]. Woody plants, unlike hardwoods, enrich and purify the air throughout the year and can be used for single and group planting when creating hedges and borders, as well as green gardens. All year round, they enrich the air with oxygen, absorb street noises, and lower the air temperature. However, the conservation of flora is necessary not only for individual components, but also for the entire population diversity. Salinized land, unfavorable climate and other environmental factors are among the obstacles or restrictions to the introduction of new species of trees and shrubs, especially evergreen ones, in arid areas [2] [3]. The urban environment differs from the natural environment in terms of the degree of illumination, the amount of solar radiation, air temperature and humidity, soil properties, etc. In this regard, green plants only with proper planning, selection of assortment, sufficient quantity and good care ensure the improvement of the ecological state of the city. For scientifically based gardening, it is necessary to have objective ideas not only about the quantity and quality of existing plantings, but also to know the ecological and physiological state of each species, which allows us to assess the role of plants in improving the quality of the environment [4]. The sharply continental climate, aridity of the territory, increased wind activity and salinity of the soil contribute to the aggravation of environmental problems in the cities of the southern Aral sea region. The deteriorating environmental situation in Nukus requires the development of a specific gardening strategy aimed at creating sustainable urban plantings of various types. In this regard, we conduct research on the biological characteristics of ornamental woody plants in urban conditions. The range of tree and shrub species used in the landscaping of the city of Nukus remains quite poor today [5]. The predominant tree species are P. alba L., P. nigra L., P. diversifolia L., F. excelsior L., F. pensylvanica Marsh., Fraxinus potamaphylla Herd, S. excels S. Gmel, S. babylonica L., S. alba L., Juniperus communis L. In the landscaping of Nukus, introduced plants are also used, which have adapted to local conditions, although they are damaged by frosts. These include C. bignonioides Walt, Ulmus pumila L., F. pensylvanica Marsh.