伏牛山森林生态系统灌木植物功能群分类

伏牛山国家级自然保护区位于中国东部亚热带和暖温带的过渡区,植被优势种明显,以灌木优势种为主体进行植物功能群分类,可以对森林生态系统的功能、框架结构及类群分布有一个明确的认识.采用群落生态学的调查方法,在伏牛山南北坡设置66个典型样方.根据调查结果,通过计算重要值,选取优势度相对较大的灌木树种进行种间联结及相关性分析,以X2(卡方)检验为基础,结合联结系数AC和共同出现百分率PC来测定灌木优势种间的联结性,根据优势种间的联结性及其在海拔梯度上的变化异同来划分植物功能群,把灌木优势种划分为7组植物功能群.植物功能群间物种表现出显著正联结,一起在同一生境中出现的几率较大,在长期的生长演化过程中,能适应相似的资源环境和对干扰有相似的响应,所以将其划分同一组植物功能群.植物功能群内有一些重要的形态特征有相似之处,功能群间的形态特征有明显的区别,如叶片的大小、形状等,功能群的这些相似及区别还需要生理生态学的进一步研究.     

伏牛山自然保护区森林生态系统草本植物功能群的分类

伏牛山国家级自然保护区是中国东部森林样带中的亚热带和暖温带的结合点,随着环境梯度(海拔)的变化,林下植物优势种变化明显.草本植物对环境的反应较为敏感,能较好的反映出植被与环境的动态关系.采用群落学调查方法,对伏牛山南北坡的植被进行调查.以X2检验为基础,结合联结系数AC和共同出现百分率PC来测定草本层优势种间的联结性,根据优势种间的联系性及其在海拔梯度上的变化异同,以优势种为主体划分伏牛山自然保护区林下草本植物功能群.研究结果表明,以优势种为主体对森林生态系统草本植物进行功能群划分可行性高,有较强的代表性.对草本优势种共划分了7组植物功能群:Ⅰ"伴人型",Ⅱ"高山型",Ⅲ"阴湿型",Ⅳ"耐旱型",Ⅴ"林隙型",Ⅵ"基础型",Ⅶ"原始型".每一组都有其特定的分布区域和形态特征,较好了反应出环境与植被的动态关系,为今后森林生态系统研究和植物功能群划分寻找新的思路.     

天然林和人工林外来入侵和本地植物对比研究: 以弄岗国家级自然保护区为例

外来植物的入侵严重威胁了自然保护区的生物多样性。为探讨自然保护区内天然林和人工林林下外来植物入侵状况及其与本地优势植物的种间关系, 本研究以弄岗国家级自然保护区为研究区域, 结合保护区内4种生境72个样方的野外调查数据, 利用生态位宽度、生态位重叠和种间联结指数比较了不同生境中外来入侵草本植物的多样性和生态位宽度以及外来入侵草本植物与本土优势草本植物的生态位重叠和种间联结。结果表明: 弄岗国家级自然保护区4种生境共记录6种外来入侵草本植物, 隶属于3科6属, 其中菊科物种数量最多。外来入侵植物多样性呈现出秋枫(Bischofia javanica)人工林 > 麻竹(Dendrocalamus latiflorus)次生林 > 人面子(Dracontomelon duperreanum)人工林 > 广西澄广花(Orophea polycarpa)次生林的特征。除广西澄广花次生林生境的外来入侵草本植物丰富度与本土草本植物丰富度呈显著正相关外, 其余生境均无显著的相关关系。三叶鬼针草(Bidens pilosa)的生态位宽度最大, 为4种生境均有分布的外来入侵植物。4种生境的外来入侵植物与本土优势植物生态位重叠和种间联结程度均较低, 种间竞争较弱。本研究明确了弄岗国家级自然保护区天然林和人工林中外来入侵草本植物的分布及其与本土草本植物的种间关系。     

山西太岳山辽东栎群落林下草本植物功能群分类

辽东栎(Quercus wutaishanica)林是暖温带落叶阔叶林区域典型地带性植被类型之一。辽东栎作为山西具有代表性的地带性植被类型,是山西森林的主要组成部分。以往的研究以辽东栎为对象的成果颇多,对其林下草本层的研究少有报道。太岳山辽东栎群落随着环境梯度(海拔)的变化,林下植物优势种变化明显,草本植物对环境的反应较为敏感,能较好地反映出植被与环境的动态关系。采用样方法,调查了太岳山七里峪辽东栎群落,根据调查结果,通过计算重要值并结合频度,在辽东栎林下草本层选取27个优势度相对较大的物种进行种间联结和相关性分析。以χ~2检验为基础,结合联结系数AC和共同出现百分率PC来测定辽东栎林林下草本层优势种种间联结性,并根据此联结性及其聚类分析,以优势种为主体划分植物功能群。结果显示如此划分可行性高,可将辽东栎林下草本层优势种共划分为七组功能群:Ⅰ"广布型",Ⅱ"森林边缘草甸型",Ⅲ"湿润疏林型",Ⅳ"耐寒林隙型",Ⅴ"山坡林缘型",Ⅵ"高山型",Ⅶ"阴湿型"。研究表明:通过水热梯度下草本植物功能群的变化,能较好地反映出辽东栎与环境的相互关系。     

黄淮海平原农业景观非农生境植物功能群特征分析

植物功能群的划分有助于对生态系统结构、功能和服务的理解与认知,为更好的了解农业景观中残存的各非农生境在区域生物多样性保护和生态系统服务中的地位和作用。在黄淮海平原典型区域布点,对区内主要非农生境(林地、树篱、田间道路、沟渠)中的植物群落进行调查,并基于植物功能群分类结果探讨了其特征和在生态系统服务上的贡献。结果显示:(1)从物种数量来看,双子叶植物占绝对优势,单子叶植物在各生境中均较少,但却具有较高的群落地位,一年生和多年生植物物种丰富度及重要值基本一致;(2)从生境类别来看,田间道路和树篱等生境中一年生和单子叶植物更具有优势,随着人类扰动强度的减弱,在林地和沟渠生境中,开始有大量的多年生物种出现,尽管这些物种多为偶见种。(3)常见种多为一年生双子叶植物,种类不多,但群落地位极高,而偶见种中存在大量的多年生双子叶物种。深入分析认为,在黄淮海平原农业景观中,总体上各非农生境均处于群落演替早期,以一年生和单子叶植物功能群构成了群落主体,群落结构简单,优势种群明显,随着干扰强度的相对降低,林地与沟渠生境中的多年生和双子叶物种大量出现,偶见种增加,优势种地位下降。从物种多样性保护与生态系统服务提供综合考虑的角度看,尽管这些非农生境发挥了重要作用,但所能发挥的作用还很有限,未来仍需进一步减弱人类活动对非农生境的干扰,从而进一步提高区域生态系统服务的总体水平。     

伏牛山自然保护区森林生态系统植物功能群光合特性

植物功能群(PFG)把一系列植物归为一个功能团体,可以作为植被随环境动态变化的基本单元,简化相关研究。植物功能群内不同物种的生理特性差异是功能群存在的基础,也影响着功能群整体的功能。采用种间联结法并结合优势种在海拔梯度上的变化,将伏牛山自然保护区森林生态系统各层优势种划分为4组植物功能群,研究每组植物功能群内不同物种的光合特性。对光合-光响应、最大净光合速率(Pn)、暗呼吸速率(Rd)、光补偿点(LCP)、光饱合点(LSP)和表观量子效率(AQY)等指标进行分析和比较,结果表明:植物功能群内不同物种的光补偿点和暗呼吸速率的变异系数最高分别达70.47%和74.29%,功能性状存在着显著的互补性,这是物种能长期共存的主要原因。乔木的最大净光合速率在7—8μmol CO_2m~(-2)s~(-1)之间,对高光强的适应能力较高。同一功能群内各层植物光饱合点在1200—1500μmol m~(-2)s~(-1)之间,差别不大。林下灌木、草本植物对弱光的利用效率较乔木高。同一功能群内物种功能性状的差异及不同植物功能群间整体性状的差异,影响着森林生态系统的结构、功能、过程和生态系统服务。     

孔雀河下游断流河道的环境特征及物种间关系

基于孔雀河下游断流河道的环境因子和植被样地数据,采用聚类与CCA排序法,分析了生境的退化特征以及物种间的相互关系,结果表明:1)断流河道退化生境分为绿洲-荒漠过渡类型、轻度荒漠化类型和盐土荒漠化类型。绿洲-荒漠过渡类型地下水位低、盐分含量相对较低,植被盖度相对较高,土壤维持着原砂质壤土,为潜在退化型;轻度荒漠化类型地下水位、土壤质地与含盐量与前者基本相同,土壤未明显退化,但植被盖度低于10%,植物种类与个体数目都较低,属于轻度退化型;盐土荒漠化类型地下水位高、盐分含量高,土壤机械组成中砂粒比重较大、无建群种幸存,属于重度退化型。2)绿洲-荒漠过渡类型总体联结性为显著正联结,正负联结比小于1,生态系统表现为建群种维系物种关系的不稳定状态;轻度荒漠化类型总体联结性为不显著负联结,正负联结比小于1,表现出生态系统进入退化演替的阶段;盐土荒漠化类型总体联结性为显著正联结,正负联结比大于1,表现出重度退化群落的种间平衡状态,物种间以达到稳定共存,其中,真盐生植物对这种平衡的维持起着重要的作用。3)CCA排序表明,绿洲-荒漠过渡类型形成以胡杨为中心的种间正联结,幸存于盐分适中、水分养分相对较高的生境;轻度荒漠化类型,形成以多枝柽柳与刚毛柽柳相互依存的不显著负联结,幸存于土壤养分、水分相对较低的生境;盐土荒漠化类型形成以盐爪爪、盐节木、盐穗木等真盐生植物维系的显著正联结,幸存于土壤贫瘠、地下水位浅、盐分含量高、沙化严重的生境。     

黄河中下游典型河岸带植物物种多样性及其对环境的响应

为维持河岸带生态系统的完整,对河岸带的物种多样性研究十分必要。本研究采用Braun-Blanquet多度等级划分标准结合样方法调查了黄河中下游典型河段河岸带植物群落物种多样性特征,并探讨其与环境因子的关系。结果表明:黄河中下游典型河段河岸带调查的52个群落样方中,共有36科78属86种植物,群落物种组成较为丰富,但优势种并不明显。单一群落样方中,物种组成简单,不同样方之间物种组成与多样性存在明显差异,其中,受干扰较重的样方物种多样性较低,表明研究区河岸带植物物种多样性深受人为干扰所造成的生境破碎的影响。冗余分析表明,海拔和至河流距离是黄河中下游河岸带植物多样性的重要影响因子。     

北京市自然保护区植物群落对干扰胁迫的抵抗力分析

在城市规模不断扩张的过程中,北京市自然保护区植物群落正面临着前所未有的干扰胁迫.研究植物群落对干扰的抵抗力具有理论和实践意义.在北京市松山和喇叭沟门两个自然保护区植物群落中调查了22个样地,记录到213种植物,测度了33个植物功能性状.在集成前人成果的基础上,量化了每个性状在基建工程、放牧或旅游践踏、火烧以及外来种入侵干扰下的功能属性;计算了物种、功能群和群落尺度上的功能指数;利用回归分析方法描绘了物种丰富度与功能指数间的关系.结果表明:(1)植被恢复力指数(plant restoration index)在4.36-10.15之间,草本植物大于木本植物;物种对不同干扰的抵抗力功能指数(resistance index to disturbance)变化范围分别为:放牧10.27-23.15,乔木和灌木大于其他生长型植物;火烧9.01-22.15,乔木大于灌木,后者又大于草本;外来种入侵4.41-10.54,乔木大于其他生长型.(2)以山杨(Populus davidiana)为优势种的群丛,其植被恢复力以及对干扰的抵抗力较其他群丛强.(3)在乔木层和草本层,物种丰富度与功能指数不相关;在灌木层,物种丰富度与放牧、火烧和外来种入侵的功能指数正相关,与植被恢复指数不相关.作者建立了研究区域物种、功能群和群落尺度上的植被功能指数数据库,为自然保护区植被结构调整和恢复提供了技术支撑.群落尺度的功能值取决于优势种的功能值,物种多样性是生态系统功能维持的重要基础.物种的功能冗余可能与植物群落结构层次以及干扰类型有关.本文结果为生态系统物种功能冗余假说提供了一个例证.     

秦岭山地油松天然次生林灌木层主要种群种间联结性与功能群划分

运用χ²检验、联结系数和共同出现程度,测定秦岭山地油松天然次生林灌木层20个主要植物种群的种间联结性.结果表明: 在190个种对中,具有较明显正联结的种对数占总种对数的7.4%,胡枝子与胡颓子、漆树与油松、卫矛与毛樱桃等表现为极显著正联结,绝大多数种对表现为弱联结,正负联结比值均小于1.表明灌木层主要植物种群种对间联结较松散,物种之间存在一定的独立性,处于动态演替的中期阶段,群落稳定性较差.通过种间联结和聚类分析,结合生物学和生态学特征,将灌木层20个主要植物种群划分为4个功能群.同一功能群内物种的生态要求和资源利用方式相近,联结紧密,而不同功能群间联结较为松散.     

伊洛河流域外来草本植物分布格局

外来生物入侵及其防治已经成为生态学关注的重点和热点问题.目前的研究主要集中在外来入侵种上,然而入侵种仅占外来种中很少一部分,因此,研究外来种现有分布格局对研究生物入侵及其防治有重要意义.以伊洛河流域草本植物群落中的外来种为对象,沿河从河源地到入黄河口选取典型样地,在调查流域内草本植物群落中物种组成的基础上选取外来种,并对外来种种类组成及其分布格局进行研究.结果表明:流域内有外来草本植物27种,分属于15科,种类较多的科为菊科、苋科和豆科;引入方式以有意引种为主.流域横向不同生境间,河滩地在水流的养分富集、季节性洪水物理干扰及人为活动扰动作用下,呈现出受外来种分布较多,而受人类活动扰动最强且营养丰富的农田分布较小的分布格局;纵向环境梯度下,上游河源山地属于自然植被区,人为干扰较轻,且受外来种影响较小;中游丘陵区从自然生态系统向农业生态系统的过渡区域,人类活动的扰动有所加强;下游平原农业区,人类活动强烈,区域内以人工生态系统为主,群落物种组成简单但受外来种影响最大,受自然环境和人类活动的双重影响.不同物种在不同生境间差异明显,其中,小蓬草、钻叶紫菀和反枝苋广泛分布于3种生境中.总体上,伊洛河外来草本植物分布格局在自然因素的基础上强烈受人为因素的影响,呈现出从上游到下游逐渐增多的趋势.     

An ecosystem engineer,the beaver,increases species richness at the landscape scale

Ecosystem engineering - the physical modification of habitats by organisms - has been proposed as an important mechanism for maintaining high species richness at the landscape scale by increasing habitat heterogeneity. Dams built by beaver (Castor canadensis) dramatically alter riparian landscapes throughout much of North America. In the central Adirondacks, New York, USA, ecosystem engineering by beaver leads to the formation of extensive wetland habitat capable of supporting herbaceous plant species not found elsewhere in the riparian zone. We show that by increasing habitat heterogeneity, beaver increase the number of species of herbaceous plants in the riparian zone by over 33% at a scale that encompasses both beaver-modified patches and patches with no history of beaver occupation. We suggest that ecosystem engineers will increase species richness at the landscape scale whenever there are species present in a landscape that are restricted to engineered habitats during at least some stages of their life cycle.     

黄河山东段河岸带春季大型底栖动物群落结构与多样性

河岸带是河流生态系统与陆地生态系统相互作用的生态交错带,具有明显的边缘效应和丰富的生物多样性。近年来,由于受人类活动(如水利工程、堤坝和农业生产等)的干扰,黄河下游河岸带生态系统受到严重破坏。为了解黄河下游河岸带大型底栖动物的群落结构现状和影响因素,于2015年5月对黄河山东段河岸带8个断面的底栖动物群落进行了系统调查,采用相对重要性指数、物种多样性指数和均匀度指数等方法分析该区域大型底栖动物的群落特征。调查期间共采集到37种底栖动物,其中,环节动物3种,软体动物7种,水生昆虫27种。底栖动物物种组成主要以水生昆虫为主,尤其是摇蚊幼虫。该段河岸带大型底栖动物的平均密度为(2 129±436)ind/m2,平均生物量为(2.20±0.75)g/m2。就空间分布而言,各断面底栖动物的种类数、优势种、现存量和多样性均呈现出明显的空间分布差异,且呈现出不规则波动,这表明河岸带受到严重的人为活动干扰。综合分析表明,各断面的河岸带形态(如宽度和生境类型)和水生昆虫的繁殖行为是影响黄河山东段河岸带底栖动物空间分布的主要因素。     

长江三峡地区干流河岸植物群落的初步研究

以长江三峡干流河岸植物群落为研究对象,对群落的物种组成、物种多样性进行了分析,并利用ＴＷＩＮＳＰＡＮ方法对植物群落进行高等级式划分。结果表明：河岸植物区系组成较为复杂,以温带成分为主,有着较高比率的世界分布成分。植物生活性方面,草本种类的比率略高于木本种类,藤本种类较少。藻、草丛群落之间的物种多样性差异不显著。ＴＷＩＮＳＰＡＮ和ＤＣＡ分析显示,河岸植物群藻可分为６大类群,这些类群呈现沿湿度梯度方向     

Vulnerability of riparian ecosystems to elevated CO2 and climate change in arid and semiarid western North America

Riparian ecosystems, already greatly altered by water management, land development, and biological invasion, are being further altered by increasing atmospheric CO₂ concentrations ([CO₂]) and climate change, particularly in arid and semiarid (dryland) regions. In this literature review, we (1) summarize expected changes in [CO₂], climate, hydrology, and water management in dryland western North America, (2) consider likely effects of those changes on riparian ecosystems, and (3) identify critical knowledge gaps. Temperatures in the region are rising and droughts are becoming more frequent and intense. Warmer temperatures in turn are altering river hydrology: advancing the timing of spring snow melt floods, altering flood magnitudes, and reducing summer and base flows. Direct effects of increased [CO₂] and climate change on riparian ecosystems may be similar to effects in uplands, including increased heat and water stress, altered phenology and species geographic distributions, and disrupted trophic and symbiotic interactions. Indirect effects due to climate‐driven changes in streamflow, however, may exacerbate the direct effects of warming and increase the relative importance of moisture and fluvial disturbance as drivers of riparian ecosystem response to global change. Together, climate change and climate‐driven changes in streamflow are likely to reduce abundance of dominant, native, early‐successional tree species, favor herbaceous species and both drought‐tolerant and late‐successional woody species (including many introduced species), reduce habitat quality for many riparian animals, and slow litter decomposition and nutrient cycling. Climate‐driven changes in human water demand and associated water management may intensify these effects. On some regulated rivers, however, reservoir releases could be managed to protect riparian ecosystem. Immediate research priorities include determining riparian species' environmental requirements and monitoring riparian ecosystems to allow rapid detection and response to undesirable ecological change.     

伊洛河流域草本植物群落物种多样性

生物多样性沿环境梯度的变化是生物多样性研究的重要内容,环境梯度包含了多种环境因子(海拔高度、水热条件、人类扰动等)的综合。以伊洛河流域草本植物群落为对象,沿河从入黄河口到河源地选取典型样地调查研究伊洛河流域草本植物群落物种多样性及其分布格局。结果表明:物种丰富度和Shannon-Wiener多样性指数沿河均稍呈"S"型曲线变化,不同群落类型中分布格局差别不大,各群落类型中的物种丰富度和多样性均呈现出中游丘陵山地交界区最高,上游河源区次之,下游平原地区最低的趋势;β多样性指数的变化趋势与α多样性较一致,总体上呈现出中游丘陵山地区物种更替速率较快,平原区更替较慢;在流域内上游河源地属于自然植被区,人为干扰较轻,具有较高的物种多样性,物种替代主要受物种的竞争扩散能力和生境条件的制约;在下游平原农业区,人类活动强烈,区域内以人工生态系统为主,物种组成简单,物种替代具有跳跃性的特征,主要受人类活动的制约;在中游从自然生态系统向农业生态系统的过渡区域,人类活动的扰动有一定的强度,导致该区域内自然分布种和伴人种混合生长,具有较高的物种多样性和较快的物种替代速率。总体上伊洛河流域草本植物群落物种多样性分布格局强烈的受到人类活动的影响,物种替代速率较高。     

Variation in species‐level plant functional traits over wetland indicator status categories

Wetland indicator status (WIS ) describes the habitat affinity of plant species and is used in wetland delineations and resource inventories. Understanding how species‐level functional traits vary across WIS categories may improve designations, elucidate mechanisms of adaptation, and explain habitat optima and niche. We investigated differences in species‐level traits of riparian flora across WIS categories, extending their application to indicate hydrologic habitat. We measured or compiled data on specific leaf area (SLA ), stem specific gravity (SSG ), seed mass, and mature height of 110 plant species that occur along the Colorado River in Grand Canyon, Arizona. Additionally, we measured leaf δ¹³C, δ¹⁵N, % carbon, % nitrogen, and C/N ratio of 56 species with C3 photosynthesis. We asked the following: (i) How do species‐level traits vary over WIS categories? (ii) Does the pattern differ between herbaceous and woody species? (iii) How well do multivariate traits define WIS categories? (iv) Which traits are correlated? The largest trait differences among WIS categories for herbaceous species occurred for SSG , seed mass, % leaf carbon and height, and for woody species occurred for height, SSG , and δ¹³C. SSG increased and height decreased with habitat aridity for both woody and herbaceous species. The δ¹³C and hence water use efficiency of woody species increased with habitat aridity. Water use efficiency of herbaceous species increased with habitat aridity via greater occurrence of C4 grasses. Multivariate trait assemblages differed among WIS categories. Over all species, SLA was correlated with height, δ¹³C, % leaf N, and C/N; height was correlated with SSG and % leaf C; SSG was correlated with % leaf C. Adaptations of both herbaceous and woody riparian species to wet, frequently inundated habitats include low‐density stem tissue. Adaptations to drier habitats in the riparian zone include short, high‐density cavitation‐resistant stem tissue, and high water use efficiency. The results enhance understanding about using traits to describe plant habitat in riparian systems.     

Gallery Forest or Herbaceous Wetland? The Need for Multi‐Target Perspectives in Riparian Restoration Planning

Much riparian restoration focuses on establishment of gallery forests, with relatively limited effort to restore herbaceous wetlands as key components of riparian landscape mosaics. Multiple reasons for this include inherent cultural or esthetic preferences, greater availability of scientific knowledge to support riparian forest restoration, and choices of ecological indicators commonly used for monitoring and assessment. Yet riparian herbaceous wetlands have declined dramatically as a result of river regulation and agricultural development, leading to losses of important habitats and ecosystem services that differ from those provided by gallery forests. As an alternative to a single‐minded focus on tree establishment, we advocate restoration of diverse and dynamic habitat mosaics in the context of natural variability of flow and sediment regimes. Landscape context should inform active restoration activities at the local scale, such that riparian forests are not planted in ecologically inappropriate sites. Models are needed to match life history requirements of particular wetland herbaceous plant species with details of flow and sediment transport regimes. We emphasize the importance of herbaceous wetlands as a critical and often overlooked component of riparian ecosystems, and the need for both passive and active restoration of fluvial marshes, sloughs, wet meadows, alkali meadows, off‐channel ephemeral ponds, and other critical floodplain communities associated with herbaceous plant dominance.     

Butterflies as an indicator group of riparian ecosystem assessment

Riparian ecosystems play an important role in modulating a range of ecosystem processes that affect aquatic and terrestrial organisms. Butterflies are a major herbivore in terrestrial ecosystems and are also common in riparian ecosystems. Since butterflies use plants for larval food and adult nectar sources in riparian ecosystems, butterfly diversity can be utilized to evaluate riparian ecosystems. We compiled butterfly data from 33 sites in three riparian ecosystem types across the country and compared butterfly diversity in terms of number of species and quality index in relation to riparian environmental variables. Number of butterfly and plant species was not different among three riparian habitat types. Additionally, there was no significant ecological variable to distinguish the butterfly communities on three riparian habitats. Non-metric multi-dimensional scaling ordination showed that butterfly communities in three riparian ecosystem types differed from each other, and butterfly riparian quality index was the main variable for butterfly assemblages. Five indicator species for moor and another five species for riverine riparian ecosystems were identified. Three and one indicator species for moor and riparian ecosystems, respectively, were plant specialists, while 44 butterflies were general feeders, feeding on a wide range of hostplants in several habitats. These results suggest that butterfly species use actively riparian habitats for nectar and larval food, and the butterfly riparian quality index can be employed to track faunal change in riparian habitats, which are frequently threatened by disturbances such as water level and climate changes, and invasive species.