Thriving green havens in baking deserts:Plant diversity and species composition of urban plantations in the Sahara Desert

Hot arid zones represent vital reservoirs of unique species and ecosystems,holding significant importance for biodiversity.This study aimed to explore the plant diversity associated with tree plantations in urban ecosystems under hyper-arid climatic conditions in the Sahara Desert of Algeria.In May 2022,30 quadrats measuring 1 m^(2) each were established at the base of Phoenix dactylifera,Leucaena leucocephala,and Tamarix aphylla,corresponding to the dominant tree species in each of three plantations.In each quadrat,the plant quantitative inventory was conducted to measure plant diversity and similarity among the studied plantations.Based on this,we assessed the plant functional traits and rarity/abundance status of the flora.The findings revealed a diverse flora associated with the studied plantations,comprising 29 plant species grouped into 27 genera and 12 families.Notably,Poaceae(accounting for 30.8% of the flora),Asteraceae(25.0%),and Zygophyllaceae(21.6%)were well-represented.With an overall density of approximately 555 individuals/m^(2),Zygophyllum album(120 individuals/m^(2))and Polypogon monspeliensis(87 individuals/m^(2))emerged as the most abundant species.Functional trait analysis underscored the pivotal role of therophytes(constituting over 50.0% of the flora)and anemochorous species(33.0%-62.5%).Phytogeographic analysis emphasized the prevalence of the Saharo-Arabic element(constituting over 31.0% of the flora)and the Mediterranean Saharo-Arabic element(9.5%-21.5%).The Cosmopolitan element thrived under disturbance factors,recording percentages from 13.0% to 20.0% of the plant community.The rarity/abundance status of the flora emphasized the significance of rare,common,and very common species in the studied plantations.These findings could provide fundamental data for the effective control and management of biodiversity in hot hyper-arid urban ecosystems.

Plant biological diversity in natural secondary forests on Mao'er Mountains

The forest plant biological diversity investigations were conducted in Laoyeling Forest Ecological Experimental Station on Mao’er Mountains in eastern Heltongjiang Province. Sample plots were six different forest communities. Field works were divided into three seasons : spring, summer and autumn in one year. The results showed that forest plant biological diversity varied with seasons as well as growth forms. Herb species diversity values were the highest in the community growth forms. Diversity indices No, H’ and E1 were selected out as the best richness, diversity and evenness indices to indicate the biological diversity in forest community.

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.

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.

The Impact of Urban Expansion on Plant Diversity Change in Karst Regions of Southwest China

Biodiversity is vital for the integrity and stability of ecosystems and sustainable development.Karst regions of Southwest China is featured for undulating and broken karst terrain as well as high plant diversity.Land use changes induced by the growing population and expanding human settlement have threatened biodiversity preservation in this region.However,the impact of urban expansion on plant diversity remains unclear here.This study focuses on how expanding countryside landscapes affect the recovery rate of plant diversity and demonstrate how urban expansion affects plant diversity conservation in karst regions of Southwest China.In situ biodiversity investigations and multisource remote sensing images were combined to analyze the role of human settlement evolution in the conservation of plant diversity using descriptive statistics and regression analysis.Unmanned vehicle images,historical aerial photographs,and long-term remote sensing images were used to observe the human settlement pattern changes over 40 yr and found that plant diversity is restored faster in countryside ecosystems than in island ecosystems restricted by water.Forests,however,contribute the most to plant diversity conservation in both ecosystems.While the forest area is stable during urban expansion,massive forest patches play an essential role in plant diversity conservation.Arable lands and grasslands shrank but with a fragmenting trend,which was conducive to preserving plant diversity,whereas increased and regularized large patches of built-up areas were not beneficial to plant diversity.Accordingly,forest protection should be prioritized to coordinate future socioeconomic development and plant diversity conservation in karst and broader regions.Furthermore,large built-up patches should be limited,and the irregularity should be improved during urban expansion.Irregular shaped cultivated land and grassland were suggested to promote biological information exchanges as landscape corridors.

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.

Leguminosae plants play a key role in affecting soil physical-chemical and biological properties during grassland succession after farmland abandonment in the Loess Plateau,China

Leguminosae are an important part of terrestrial ecosystems and play a key role in promoting soil nutrient cycling and improving soil properties.However,plant composition and species diversity change rapidly during the process of succession,the effect of leguminosae on soil physical-chemical and biological properties is still unclear.This study investigated the changes in the composition of plant community,vegetation characteristics,soil physical-chemical properties,and soil biological properties on five former farmlands in China,which had been abandoned for 0,5,10,18,and 30 a.Results showed that,with successional time,plant community developed from annual plants to perennial plants,the importance of Leguminosae and Asteraceae significantly increased and decreased,respectively,and the importance of grass increased and then decreased,having a maximum value after 5 a of abandonment.Plant diversity indices increased with successional time,and vegetation coverage and above-and below-ground biomass increased significantly with successional time after 5 a of abandonment.Compared with farmland,30 a of abandonment significantly increased soil nutrient content,but total and available phosphorus decreased with successional time.Changes in plant community composition and vegetation characteristics not only change soil properties and improve soil physical-chemical properties,but also regulate soil biological activity,thus affecting soil nutrient cycling.Among these,Leguminosae have the greatest influence on soil properties,and their importance values and community composition are significantly correlated with soil properties.Therefore,this research provides more scientific guidance for selecting plant species to stabilize soil ecosystem of farmland to grassland in the Loess Plateau,China.

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.

Dragonflies in the City:Diversity of Odonates in Urban Davao,Philippines

Dragonflies are well-known group of insects because of their biological and ecological importance in a community,that is,they indicate the environmental health of an ecosystem.However,in an urban ecosystem,there are many threats that can affect the assemblages of dragonfly species such as the intensification of urbanization which contributes biodiversity loss of most dragonfly species.This study aimed to identify dragonfly species and determine the species richness,relative abundance,species diversity,evenness and effective number of dragonflies in selected areas in Davao City.Opportunistic sampling using sweep net and photo documentation were used during the study.The sampling lasted for three months from June 2017 to August 2017.A total of 962 individuals of dragonflies were observed and recorded comprising of six species of dragonflies from six different genera of one family.Orthethrum sabina was the most abundant among the six species recorded in all sampling sites.The species richness was six.Low species diversity was obtained in all sampling which shows that the sites were not evenly distributed and indicating that the study sites were not diverse in terms of the number of species and highly disturbed.

Effects of vegetation type on soil microbial community structure and catabolic diversity assessed by polyphasic methods in North China

Soil microbes play a major role in ecological processes and are closely associated with the aboveground plant community. In order to understand the effects of vegetation type on the characteristics of soil microbial communities, the soil microbial communities were assessed by plate counts, phospholipid fatty acid （PLFA） and Biolog microplate techniques in five plant communities, i.e., soybean field （SF）, artificial turf （AT）, artificial shrub （AS）, natural shrub （NS）, and maize field （MF） in Jinan, Shandong Province, North China. The results showed that plant diversity had little discernible effect on microbial biomass but a positive impact on the evenness of utilized substrates in Biolog microplate. Legumes could significantly enhance the number of cultural microorganisms, microbial biomass, and community catabolic diversity. Except for SF dominated by legumes, the biomass of fungi and the catabolic diversity of microbial community were higher in less disturbed soil beneath NS than in frequently disturbed soils beneath the other vegetation types. These results confirmed that high number of plant species, legumes, and natural vegetation types tend to support soil microbial communities with higher function. The present study also found a significant correlation between the number of cultured bacteria and catabolic diversity of the bacterial community. Different research methods led to varied results in this study. The combination of several approaches is recommended for accurately describing the characteristics of microbial communities in many respects.

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.

Soils Typology and Floristic Diversity of the Forest of the“Cite Scientifique”of Brazzaville,Congo

A study of the typology of soils and floristic diversity was carried out in the forest of the “Cité Scientifique” of Brazzaville. The study aimed to assess the influence of soil cover on the distribution of taxa. The study covers 18 plots of 625 m2 each, distributed in different soil profiles. The floristic inventory concerns the measurement of diameter of trees with dbh ≥ 10 cm and the counting of herbaceous and shrubs of dbh < 10 cm. The floristic composition reveals a total of 129 plant species distributed in 48 families dominated by Fabaceae and a preponderance of pioneer taxa. The Jaccard coefficients of similarity reveal a low degree of homology of woody plots, whereas for the flora as a whole, the floristic composition is heterogeneous. The Shannon biological diversity index of ligneous varies from 0.6 to 2, against a maximum diversity of 0.69 to 3. The Pielou index of ligneous (0.5 to 0.9) does not reveal any dominance. Soil cover consists of ferrallitic and podzol soils. Their texture is sandy, weakly structured, fragmentary polyhedral throughout the profile, but lumpy and/or nuciform at the surface and sub angular in depth. The porosity decreases proportionally with the depth and thickness of the horizons. The floristic analysis presents an ecosystem with a low degree of diversification for a high floristic richness. The preponderance of anthropization markers is a proof of its very advanced state of disturbance. The study shows that soil cover does not influence the distribution of timber. Indeed, the establishment and development of pioneer species are less prone to soil properties.

Floristic diversity and structural parameters of the Brazzaville Patte d’Oie forest, Congo

The flora of the Patte d’Oie forest of Brazzaville is studied according to three plots of 0.5 ha, corresponding each to one of the islet, currently constituting it. With an original area of 240 ha, put in reserve in 1938, the natural forest of the Patte d’Oie of Brazzaville covers 95 ha, less than 39% compared to initial area. Because the other main forests of Brazzaville have disappeared without delivering their biodiversity, this study is the first one which emphasizes the flora of this single ecosystem of Congo. The total floristic inventory revealed 459 trees of dbh≥10 cm on 1.5 ha;it is an average of 306 trees?ha?1. 31 species are listed for 17 families, and the best represented of which (Fabaceae, Euphorbiaceae and Rubiaceae) have a diversity varying from 13% to 19% of the inventory and a tree number oscillating from 15% to 36%. The Shannon (H') biological diversity index of the three plots is of 2.6 on average, for a maximum diversity (H'max) average of 2.9 versus an average true diversity of 15. The Pielou index is on average 0.9, whereas that of Simpson is 0.9. The coefficients of similarity of Jaccard (41.4% to 57.1%) and of the coefficient of S?rensen (58.5% to 72.7%) show the variations in the floristic composition. The followed ecological parameters show that this ecosystem is very few diversified compared to the tropical wet dense forests on the one hand, and, on the other hand, a non constant floristic composition is not. The analysis of the diametric structure by plot and the dominant and/or characteristic species give erratic curves, evidence of an insufficiency of the regenerative potential. Indeed, approximately 70% of the species are characteristic of the disturbed ecosystems (Macaranga sp.,Caloncoba welwitschii,Hymenocardia ulmoides,and Anthocleista sp.).

History,Current Status and Trends of the Investigation for Grassland Plant Resources at Home and Abroad

The existing main problems in the investigation for grassland plant resources are found out by systematically analyzing the history, current status and de- velopment trends of the investigation for grassland plant resources at home and abroad. The paper cxploratively points out that the investigation for grassland plant resources should focus on integrated muhidisciplinary research in the future, ultimately realizing highly efficient utilization and sharing of information in grassland plant resources.

Economic Development through Medicinal and Aromatic Plants(MAPs) Cultivation in Hindu Kush Himalaya Mountains of District Swat, Pakistan

Poverty is pervasive in the Swat Valley in northwestern Pakistan, and most people survive by farming small landholdings. However, many supplement their meager subsistence earnings by collecting and selling plant material for use in herbal medicine. This material is wild-harvested, but collectors seem not to fully appreciate the potential value of the plant material they collect nor the longterm impact their collection has on local plant populations. A model project supported by the International Food Policy Research Institute(IFPRI)persuaded small-scale farmers in four different villages to use some of their land for cultivating traditionally wild-harvested species of medicinal and aromatic plants(MAPs) with high market value. The farmers were provided seeds or rhizomes of five MAPs and asked to monitor their germination and growth on 25 m2 plots during a 12 month period. At the end of the study, growth and yield data from the four localities were compared and economic analyses conducted to determine the profitability of the species based on yields, prevailing market prices, and costs of production. Five of the cultivated species were subsequently marketed and their value evaluated:Sesamum indicum, Linum usitatissimum, Ocimum basilicum, Nigella sativa and Viola pilosa. The MAPs V. pilosa and O. basilicum were the most profitable,whereas Nigella sativa was the least profitable because of its low germination rate. The net income from all but Nigella was higher than that would have been earned by planting the same area with the predominant cereals or tomatoes. In addition to demonstrating the feasibility and financial benefits of cultivating MAPs as a cash crop, this model study identified a number of additional steps that would increase the benefits of MAPs cultivation in this area.A combination of specialized education, market infrastructure development and a small loans program would enable farmers to increase their agricultural income without damaging the area's plant diversity.

哈尔滨城市工业废弃地自生植物多样性与分布特征

【目的】当今城市化进程伴随大量废弃地的出现和消失,这些废弃地由于缺少管理和使用,为自生植物提供了重要生存空间。探索工业废弃地自生植物保护和创造可持续、低维护景观的潜力,具有理论和实践意义。【方法】2020年9—10月和2021年5—6月,对哈尔滨主城区7处工业废弃地进行调研,记录875个样方中自生植物物种名称、高度、盖度、生境类型、演替阶段、干扰强度、地表类型等信息。采用Kruskal-Wallis检验比较不同生境类型、演替阶段、干扰强度和地表类型的自生植物多样性差异,采用典型相关分析法(canonical correlation analysis,CCA)研究4类环境条件因素与自生植物物种分布的关系。【结果】结果表明:1)哈尔滨工业废弃地自生植物物种丰富,共记录43科、120属、168种;2)路缘和林缘自生植物多样性高于其他类型生境,演替中间阶段自生植物多样性高于其他阶段,中等强度干扰对自生植物多样性有积极影响,不同地表类型的3个多样性指数没有显著差异;3)4类环境条件因素对自生植物分布变化的解释量为1.79%,演替阶段和生境类型对物种分布起主要作用。【结论】工业废弃地保护和更新实践中应注重保护林缘和墙缘生境,保护和提升具有丰富生境和不同演替阶段的废弃地。

郑州主城区不同生境自生草本植物多样性及影响因素

【目的】城市生境是自生草本植物生长的重要栖息地,了解不同城市生境自生草本植物的空间分布格局有助于城市植物景观的规划和保育管理。【方法】采用样地调查法共设置1 667个草本样方,调查分析不同城市生境自生草本植物物种组成与多样性特征,并采用冗余分析方法探讨了自生草本植物多样性与环境因子的关系。【结果】6种城市生境共有自生草本植物291种,隶属于46科167属,以菊科、禾本科、豆科和十字花科的物种数居多;土壤废弃地、园林绿地和河流廊道所含的物种数量较多,Shannon-Wiener指数、Patrick指数和Simpson指数的均值都较大,显著高于砾石废弃地、路边缝隙和树池(P <0.05);不同城市生境的环境因子差异明显,其中河流廊道的土壤含水量最高,电导率最大,pH值最高,紧实度最小;路边缝隙的土壤紧实度最大,含水量最小,电导率最小;树池的土壤pH值最低;Spearman相关性分析结果表明土壤含水量与土壤紧实度呈显著负相关关系,与土壤电导率呈极显著正相关关系,人为干扰与土壤紧实度呈显著正相关关系;RDA结果表明人为干扰和土壤含水量对自生草本群落多样性具有极显著影响,其次是土壤电导率和土壤紧实度。【结论】土壤废弃地、园林绿地和河流廊道的微生境类型丰富,生境异质性高,能为不同生态习性自生草本植物提供生存空间,对自生草本植物多样性维持具有积极的作用。

成都四环路内工业废弃地自生植物生境及物种多样性

【目的】城市工业废弃地是自生植物重要的栖息地之一。揭示此类特殊生境中自生植物的物种组成和多样性特征,可以指导低维护植物景观的营建。【方法】采用网格布样法结合典型样点方法,选取成都市四环路内不同方位的10个重工业和轻工业废弃地,共584个样方展开自生植物调研,根据场地特征将工业废弃地生境分为荒置生境、半硬质生境、水湿生境和建筑生境四大类,在此基础上,细分出自生草地、砖石地、洼地等14种微生境,并分析不同生境和微生境中的自生植物物种组成和多样性特征。【结果】共记录到237种自生植物,隶属69科、186属。自生植物的生活型以多年生草本为主,占总物种数的30.80%。在自生植物群落多样性上,不同废弃年限和不同面积废弃地中的物种频度存在显著性差异,生境与微生境的物种丰富度差异不显著,但各生境间和微生境间的群落多样性呈极显著差异。【结论】为未来工业废弃地再利用的低维护植物规划提供了新思路,通过科学保留和利用自生植物,形成规划—“自然”设计—再规划的过程,激发工业废弃地自然恢复能力与潜力,并能最大化发挥再野化对工业废弃地生态修复和自然景观营造的作用。

长株潭城市生态绿心生物多样性调查——以陆生维管植物为例

生物多样性是生态系统健康的关键决定因素,是地球生命共同体的血脉和根基。以长株潭绿心区域陆生维管植物生物多样性调查数据为基础,将43个森林样方划分为6种植被类型17个群系,统计了各植被类型和群系物种数量;以重要值(IV)为依据,分析了乔木、灌木、草本植物的空间结构和优势度。结果表明,调查的43个森林样方中共记录有乔木种类80种;常绿阔叶林和常绿针叶林是调查样方中占比较大的2种植被型;马尾松、檵木、杨桐、杉木、苦槠、毛竹是样方中的常见种;不同样方树种数量、空间结构和重要值均有较明显的差别,不同群系空间结构有较明显的差别。乔木层树高为3~20 m,其中毛竹林群系树高差别较小,米槠林群系树高差别较大;乔木层胸径为3~40 cm,其中栓皮栎林群系的乔木胸径差别最小,米槠林群系差别最大。

北方城市绿地对大气颗粒物浓度的削减作用对比研究

尽管城市绿地能够改善空气质量,但由于实践中缺乏统一的绿地分类系统,很难从优化绿地植被结构的角度出发调节城市空气质量。因此,为了探究北方城市不同绿地削减大气颗粒物浓度效果的差异,构建了一套融入植被结构因子和物种组成的绿地分类系统,基于该分类系统,在北京、西安、宝鸡选取了5类共同常见的植被结构绿地类型,通过卫星图像判读与实地监测相结合的方式,探究了不同本底环境、植被结构、植物多样性、气象因子和时间因子对大气颗粒物浓度(PM_(2.5)与PM_(10))的影响。结果表明:(1)城市绿地率对大气颗粒物浓度造成显著影响,绿地率越高的本底环境内颗粒物浓度越低,即多绿本底<灰绿参半本底<灰色本底;(2)植被结构和植物多样性水平显著影响绿地的滞尘能力,北方城市中半开敞绿地的滞尘能力最好,其次为半闭合绿地与闭合绿地,开敞绿地滞尘能力最弱,植物多样性的增加将导致绿地内颗粒物浓度增加;(3)不同植被结构绿地内的大气颗粒物浓度受气象因素的显著影响,随温度和风速的增大而减小,随湿度的增大而增大;(4)北方城市绿地大气颗粒物浓度存在明显的季节和日变化规律,一年内大气颗粒物浓度在夏季最低,冬季最高;一天之内颗粒物浓度在8:00—10:00最低。上述研究结果以期为今后不同本底环境下以削减大气颗粒物浓度为导向的北方城市绿地规划与设计提供理论依据和实践方法。