湘中地区不同石漠化类型植物群落组成及特征

通过对湘中5县不同石漠化类型进行植被调查分析,探讨了湘中地区不同石漠化类型的植被组成和群落特征。结果表明:湘中地区不同等级石漠化类型植物群落结构简单,物种组成比较单一,优势种比较明显,中度石漠化时期出现的乔木树种是石漠化地区乔木群落演替的先锋树种;潜在石漠化地区物种组成明显增加,群落结构比较复杂,具有明显的分层现象。通过树高和胸径进行分析表明,潜在石漠化地区植物群落还处于演替阶段,将向着壳斗科植物为主要建群树种的顶级群落方向演替。     

北京怀沙河、怀九河水生植物区系初步研究

对北京怀沙河、怀九河水生植被的种类组成、分布区类型以及植被类型进行了调查.结果表明:该区共有水生植物16科18属24种;分布区类型以世界广泛分布成分最多,其次为北温带分布;水生植被分为沉水、浮水和挺水3个植被亚型和香蒲群落、慈菇群落、满江红群落、水毛茛群落、豆瓣菜群落等13个群系.     

铁路路堑边坡植被恢复调查研究

植被在边坡生态系统中有着非常重要的作用,具有涵养水源、保持水土的功能.选择四川省成昆铁路沿线不同坡向的土质路堑边坡和岩质路堑边坡,对边坡植物群落的植被类型及其结构特征、边坡植被恢复物种组成及其特征进行了调查研究.结果表明:铁路边坡自然定居物种共103种,隶属48科,全部植物中,常绿灌木2种,落叶灌木9种,藤本植物7种,1 a生草本20种,2 a或2 a以上草本植物49种;蕨类植物15种.群落物种的丰富度虽然较高,但是主要由草本植物构成,结构层次简单,应该适当的在边坡上栽植灌木或小乔木,形成坡面上乔、灌、草或草、灌相互映的群落景观.     

浙江方岩丹霞地貌岩生植被群落特征分析

对方岩丹霞地貌岩生植被群落组成成分和数量特征进行调查分析。结果表明:植被群落主要有方岩景天群落、佛甲草群落、江南卷柏群落、石韦群落等,各群落优势种较单一;群落物种组成丰富,共有高等植物61科103属128种;植物区系组成复杂,从科属的地理成分看,热带分布和温带分布较为平均,具有较明显的温带、亚热带性质,植被群落具有过渡性,这与该区处于亚热带的地理特点相一致。     

雾灵山物种多样性及垂直分布

为了探讨雾灵山植物多样性与植被分布状况，采用样方法(乔木层和灌木层的样方大小是10 m×10 m，草本层样方是1 m×1 m)，对雾灵山植被进行调查，研究表明，物种多样性与分布状况受不同的坡向、坡位、坡度、海拔、温度、水热等因素的影响。群落物种多样性表现为：草本层＞灌木层＞乔木层的特点，群落总体的物种多样性取决于草本层...     

围封对苦豆子群落多样性及土壤微生物的影响

以宁夏盐池县典型荒漠草原围封草地和放牧草地苦豆子群落为研究对象,采用野外调查与室内试验结合的方法,研究了围封对苦豆子群落植物多样性及土壤微生物数量等特征的影响,以期为荒漠草原植被恢复与治理提供参考。结果表明:围栏内物种数(15)少于围栏外(18)(围栏内以禾本科为主,围栏外禾本科、菊科、藜科占优势);围封样地苦豆子(Sophora alopecuroides)群落整体的Shannon-Wiener多样性指数、Simpson优势度指数与Pielou均匀度指数大于围栏外,多年生草本与之相似,一二年生草本与之相反;土壤微生物中细菌数量最多、放线菌次之、真菌最少,并随着土层加深而减少,围封样地微生物数多聚集在20cm以下;植物物种多样性与细菌、放线菌在围栏外样地有显著相关关系,与真菌在围栏内样地显著相关。围封增加了多年生草本植物多样性,影响微生物的土层间分布。     

浑善达克沙地微地形植被特征分析

基于浑善达克沙地不同坡向、不同坡位微地形类型,通过调查不同类型微地形植被特征,对比分析微地形对浑善达克沙地植被特性的影响。结果表明:浑善达克沙地不同微地形内植物群落物种组成、数量特征及其多样性差异显著;背风坡草本群落的优势种为羊草、狗尾草和灰莲蒿,迎风坡草本群落的优势种为虫实、洽草和雾冰藜;背风坡植被的盖度、平均高度和生物量多优于迎风坡;不同微地形Shannon指数的大小顺序为背风坡迎风坡,坡下坡中坡上。     

华安县红楼至和目坑公路建设项目植被现状调查分析

对福建省华安县公路建设项目植被现状进行调查,结果表明：现状植被生态类型除农田耕地、茶园、竹林、果林和杉木林、巨尾桉林外,余为次生杂生性灌草植被,植物区系成分和群落类型均属广布性的种类与群落类型。根据调查,果林、竹林、杉木、巨尾桉植物群落结构简单,林下植物较少,一般灌木层较为稀疏。物种多样性指数表明,评价范围内乔木层和灌木层的多样性指数较低。     

宁夏贺兰山国家级自然保护区荒漠草原植物多样性研究

采用样地调查法对宁夏贺兰山国家级自然保护区荒漠草原植物多样性进行了研究.结果表明:荒漠草原带物种丰富度指数以汝萁沟为界,在其南部由南向北物种丰富度指数呈现逐渐增加的趋势,其中插旗口最高;而在汝萁沟以北(包括汝萁沟),由南向北物种丰富度指数呈现逐渐下降的趋势.位于贺兰山南段的榆树沟和位于中段的拜寺口沟和插旗口沟的辛普森指数总体高于北段各沟,说明南段和中段各沟荒漠草原样地物种优势度小于北段各沟,但植被盖度却高于北段各沟,这可能与贺兰山不同沟道降雨量密切相关.     

承德中东部山区公路边坡类型划分及植物配置研究

基于公路边坡立地条件,对承德市中东部山区公路进行边坡类型划分,在此基础上进行植被配置研究,以提高公路边坡植被恢复措施的针对性和适应性。以承德市机场连接线为研究对象,将承德中东部山区公路边坡按坡面组成、坡度和坡向3个因子划分为土石混合斜、陡阳边坡,岩质斜阳边坡,土石混合斜、陡阴边坡和岩质斜阴边坡4种类型。通过对乡土植物和同类型公路边坡植被恢复调查,筛选出乡土植物和绿化经验植物共12种,用于研究区公路边坡植被恢复。遵循适地适树基本原理,基于物种Pearson相关分析与关联性检验,对区域内不同类型公路边进行植被恢复植物种类搭配,提高公路边坡植被恢复的科学性和合理性。     

土庄绣线菊天然灌木群落空间格局调查与分析

通过对朝阳地区土庄绣线菊天然灌木群落的调查,针对土庄绣线菊天然灌木群落的植物组成、群落的生活型构成、落的层次结构以及群落的优势种进行研究.结果表明:土庄绣线菊在样方内占有绝对优势,荆条位于第二.土庄锈线菊、荆条等龄级阶段比例较合理,在以后长期的生长过程中种类结构比例不会被打破.     

Patch-level based vegetation change and environmental drivers in Tarim River drainage area of West China

Information on vegetation-related land cover change and the principle drivers is critical for environmental management and assessment of desertification processes in arid environments. In this study, we investigated patch-level based changes in vegetation and other major land cover types in lower Tarim River drainage area in Xinjiang, West China, and examined the impacts of environmental factors on those changes. Patterns of land cover change were analyzed for the time sequence of 1987–1999–2004 based on satellite-derived land classification maps, and their relationships with environmental factors were determined using Redundancy Analysis (RDA). Environmental variables used in the analysis included altitude, slope, aspect, patch shape index (fractal dimension), patch area, distance to water body, distance to settlements, and distance to main roads. We found that during the study period, 26% of the land experienced cover changes, much of which were the types from the natural riparian and upland vegetation to other land covers. The natural riparian and upland vegetation patches were transformed mostly to desert and some to farmlands, indicating expanding desertification processes of the region. A significant fraction of the natural riparian and upland vegetation experienced a phase of alkalinity before becoming desert, suggesting that drought is not the exclusive environmental driver of desertification in the study area. Overall, only a small proportion of the variance in vegetation-related land cover change is explainable by environmental variables included in this study, especially during 1987–1999, indicating that patch-level based vegetation change in this region is partly attributable to environmental perturbations. The apparent transformation from the natural riparian and upland vegetation to desert indicates an on-going process of desertification in the region.     

Effects of vegetation structure and environmental characteristics on pollinator diversity in urban green spaces

With accelerating urbanization, insect pollinators in urban ecosystems face challenges such as reduced pollen sources, habitat fragmentation, and damage to the nesting environment. Urban green spaces (UGS) are essential for the stability of pollinator communities. However, little is known about the relationship between vertical layer heterogeneity and horizontal layer complexity of vegetation structure in UGS and pollinator communities. The present study aimed to assess how vegetation structure and environmental characteristics shape the insect pollinator community in UGS. To this end, this study was conducted with seven typical vegetation types which were selected according to the biotope mapping classification system (BMCS) in the ring parks around Hefei City, in Anhui province, China. A total of 11,401 pollinators belonging to 6 orders and 34 families were identified during the eight-month survey. Among the seven habitats under the BMCS, mainly successional short-cut shrub and partly open green space, trees two- or multi-layered broad-leaved mixed forest and partly closed green space, and mainly successional tall grass and partly open green space were identified as high-quality insect pollinator habitats. According to the results of the generalized linear regression, the explanatory power of the four best-fitting generalised linear models is relatively high (over 77%). In four optimal models, the effect of vegetation structure on pollinator community was greater than that of environmental characteristics. The redundancy discriminant analysis showed that the flowering abundance of nectar plants, herb richness, and shrub coverage rate were the three most important factors influencing insect pollinator communities, with a cumulative explanatory power of up to 78.8%. Pollinator abundance was positively influenced by spontaneous herbs and low-intensity management. However, high-intensity management, low diversity of plants, low nectar plant richness, ignoring seasonal nectar plant configuration, and dense tree distribution could limit pollinator reproduction and population growth. These results reflect the status of insect pollinator community in UGS in Hefei city and present a possible direction for improving urban green habitats and plant configurations.     

围栏封育对退化灌丛草地群落土壤特性和植被的影响

以雅鲁藏布江中游半干旱河谷山地灌丛草地群落为研究对象,采用野外调查和室内试验结合的方法,研究了围栏封育对灌丛草地植被及土壤养分含量的影响,以期为有效修复雅鲁藏布江中游河谷山地植被退化提供科学参考。结果表明:围栏封育3年土壤有机质、全磷、速效磷、速效钾含量均高于围栏外,土壤表层(0～10cm)养分含量增加显著(P<0.05),随着土壤深度的增加,土壤养分含量与围栏外逐渐趋于一致,至30～40cm到达相同水平;围栏封育后灌丛草地群落高度和产量显著增加(P<0.05),分别比围栏外增加了74%和101%,高度、产量增加主要是由禾本科和莎草科引起;围栏封育对群落组成和物种重要值产生不同程度的影响,主要表现为生物多样性增加,禾本科、莎草科等适口性好的物种重要值增加,杂草类不可食物种重要值相对下降;Rarefaction曲线法结果显示,围栏内物种多样性大于围栏外,与传统多样性指数方法结果一致。     

Variations in a regional fire regime related to vegetation type in San Diego County, California (USA)

This study considers variations in a regional fire regime that are related to vegetation structure. Using a Geographic Information System, the vegetation of San Diego County, Southern coastal California USA is divided into six generalized classes based on dominant plant form and include: herbaceous, sage scrub, chaparral, hardwood forest, conifer forest and desert. Mapped fire occurrences for the 20th century are then overlain to produce records of stand age, fire frequency and transitional stability for each of the vegetation classes. A ‘Manhattan’ similarity index is used to compare and group transition matrices for the six classes of vegetation. This analysis groups herbaceous, hardwood and conifer forests in one group, sage scrub and chaparral in a second, and desert in a third. In general, sage scrub and chaparral have burned more frequently than other vegetation types during the course of the 20^th century. Temporal trends suggest that the rate of burning in shrub-dominated vegetation is either stable (chaparral) or increasing (sage scrub), while the rate of burning in both hardwood and conifer forest is declining. This is consistent with a pattern of increased fire ignitions along the relatively low elevation urban-wildland interface, and an increase in the efficiency of fire suppression in high elevation forests. This revised version was published online in May 2005 with corrections to the Cover Date. This revised version was published online in July 2006 with corrections to the Cover Date.     

荒漠土壤植被改造过程中土壤微生物区系研究

采用稀释平板记数法对新疆古尔班通古特沙漠南缘的自然荒漠地、人工植被改造地以及二者的过度带3块不同程度盐碱地中的细菌、放线菌、真菌数量进行分析,研究地表植被与土壤微生物区系分布的关系。结果表明:在荒漠土壤改造过程中,植物种类增加,植被多样性总体水平提高。3类微生物数量都有不同程度的增加,其中细菌和放线菌在30 cm以下的深层土壤中增量较大;真菌有由中层向表层和深层迁移的趋势;真菌/细菌(B/F)值增加了2倍。从微生物角度来评价,表明种植耐盐植物(柽柳、梭梭)作为盐碱地改良的一项有效措施能够很好的改良荒漠土壤。但是各类微生物数量都没有明显的数量级上的增加,说明植被对荒漠土壤的改良作用是一个需要长期坚持的过程。     

Bird diversity in urban green space: A large-scale analysis of differences between parks and cemeteries in Central Europe

Urbanization is a permanent and still continuing expansion of human settlements and is responsible for dramatic changes of natural areas to urban areas. In traditional view, urbanization is often blamed for the loss of biodiversity and biotic homogenization of natural communities. However, for some species, urban areas, can represent suitable environment for life and even enable them to maintain stable and abundant populations. Urban ecosystems are not homogenous; within human settlements we can find several different habitats which can be occupied by species with different tolerance to certain aspects of urban life. This diversity can be exhibited by interhabitat changes in species richness, diversity and abundances of local communities. Here, we investigated biodiversity patterns in bird communities of two urban habitats, parks and cemeteries, in three Central European countries. Data on species richness, diversity and abundances of birds were collected from published papers as well as unpublished sources. Our analyses revealed that bird species richness was positively correlated with area and age of trees in both habitat types. There was however no significant relationship between species diversity and area in both habitat types. Moreover, species composition of bird communities significantly varied between cemeteries and parks with strong preference for one of habitat types in several species. Predominant occupancy of habitat type by certain species could be linked to interhabitat differences in vegetation structure, human behaviour and management. Interestingly, several bird species often recognised as urban avoiders were detected in surveyed cemeteries and parks.     

Hydric vegetation communities across rural,peri-urban,and urban zones within the Prairie Pothole Region

Wetland and pond hydric vegetation is impacted across the rural, peri-urban, and urban zones by anthropogenic activities such as agricultural production, industrial manufacturing, and urban development. Previous studies have assessed urban and rural wetland vegetation, but have rarely explored the peri-urban zone of development. Therefore, to investigate the impacts of urbanization on hydric vegetation, thirty pond sites (10 rural, 10 peri-urban, and 10 urban) were randomly selected within each of the three zones. The vegetation community at each site was assessed using a quadrat method to compare the vegetation composition. In addition, floristic quality based on the conservatism value of each plant species was used to assess wetland vegetation. Results show plant communities of rural sites differed from both urban and peri-urban sites due partly to urbanization reducing the cover of obligate wetland species. Peri-urban sites contained the highest species richness, due to the increase in introduced plants associated with urbanization. Urban sites contained the lowest species richness, some of which is due to the use of rock riprap surrounding the edges of most sites. The plant conservatism values of vegetation were not different for rural and peri-urban sites, but were significantly lower in urban sites. Information from this study is useful to wetland professionals, environmental managers, and urban planners to predict hydric vegetation responses within peri-urban areas in the Prairie Pothole Region.     

连续施用鸡粪有机肥对菜地土壤酶活性的影响

为提高菜地土壤施肥技术及推进土壤质量健康发展，采用大田试验，研究了连续4年施用不同用量（0、15、30、45 t/hm2和60 t/hm2）鸡粪有机肥对2种不同类型菜地土壤（灌漠土和潮土）脲酶、过氧化氢酶、蔗糖酶和碱性磷酸酶活性的影响。结果表明：连续4年施用鸡粪有机肥可以显著提高2种不同类型菜地土壤酶活性，但相同施用量鸡粪有机肥对2种土壤酶活性影响程度不同，无论是否施用鸡粪有机肥，灌漠土菜地土壤酶活性始终高于潮土；在同一鸡粪有机肥施用条件下，连续4年施用鸡粪有机肥更容易提高灌漠土菜地土壤脲酶、过氧化氢酶活性以及潮土菜地土壤蔗糖酶和碱性磷酸酶活性。