黄永梅
, 陈慧颖
HUANG Yongmei, CHEN Huiying
通讯作者:
收稿日期: 2018-01-17
修回日期: 2018-01-25
网络出版日期: 2018-01-28
版权声明: 2018 地理科学进展 《地理科学进展》杂志 版权所有
基金资助:
作者简介:
作者简介：黄永梅(1974-),女,内蒙古宁城人,博士,教授,主要从事植物地理学和生态水文学研究,E-mail: ymhuang@bnu.edu.cn。
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摘要
植物属性地理学是植物地理学的一个新兴研究方向,研究植物属性的地理分布规律。目前与植物属性地理相关的研究热点主要集中在植物属性的多尺度表达、植物属性的权衡关系和属性多样性与生态系统功能三个方面。比叶面积、叶干物质含量、叶氮含量、种子质量、植物高度、茎密度是最受关注的植物属性。植物属性需要在植物个体水平上进行测量,然后基于群落内物种相对优势度的加权平均上推到群落水平。植物属性权衡关系主要包括叶片经济型谱及属性与环境因子之间的权衡关系研究。全球植物属性数据库的丰富与共享,推动着植物属性地理学的蓬勃发展。当前的植物属性空间连续分布主要利用全球属性数据库和空间统计建模方法实现,但借助激光扫描和成像光谱技术直接对区域植物功能属性进行空间制图正成为植物属性地理学空间计算的新方法。植物属性的空间格局分析是植物属性地理学的重要内容之一,不仅有助于解释植物物种的适应性与分布、群落构建等问题,而且为预测全球气候变化对植物的影响提供了依据。用植物属性代替物种可以更好地解释植物分布和植物对环境适应的生理机制,所以在全球植被模型研究中开始尝试将基于物种的植被动态模型发展为基于属性的植被动态模型,这将会给全球变化下碳循环过程的模拟和陆面模式带来新的机遇和挑战。展望未来,植物属性地理学仍然需要发展新的研究手段,深化全球植物属性的空间分异规律及其与环境因子之间的关系研究,以及完善全球和区域植物属性数据库建设。
关键词：
Abstract
Plant trait biogeography is an emerging field in plant geography and it is about the geographical distribution of plant traits. At present, there are three hotspots in plant trait research, including performance of traits at multiple levels, trade-offs among traits and the relationship between trait diversity (functional diversity) and ecosystem functioning. Important traits include, for example, specific leaf area, leaf dry matter content, leaf nitrogen concentration, seed mass, plant height and stem density. Traits are measured with individual plants and can be scaled up to the community level (community weighted means and trait diversity). Trade-offs contain not only the leaf economics spectrum, but also relationships between traits and the environment. The development of global trait database largely enhances the progress of plant trait biogeography. Mapping plant traits mainly relies on the global database and spatial statistical modeling techniques, but a new method using combined laser scanning and imaging spectroscopy has been developed recently to map regional patterns of plant trait diversity. Spatial pattern analysis is an important part of plant trait biogeography. It helps to explain the distribution of plants, plant adaptability and patterns of community assembly, and then provides evidence to predict how global climate changes would influence plants. By examining plant traits instead of species, the physiological mechanisms behind plant adaptability and distribution can be better explained. Therefore, replacing species with plant traits in global vegetation models would bring new opportunities and challenges for global carbon cycle models and land surface models under global climate changes.
Keywords：
生物属性地理学(trait biogeography)也称之为生物功能地理学(functional biogeography),研究不同水平(种、群落、生态系统)的生物属性的地理分布规律(Violle et al, 2014),其中植物属性地理学发展最快。植物地理学是研究生物圈中各种植物和植被的地理分布规律、生物圈各结构单元(各地区)的植物种类组成、植被特征及其与自然环境之间相互关系的科学(武吉华等, 2004; Violle et al, 2014)。植物属性(plant traits)反映植物对环境的响应和适应,包括植物的生理和形态适应特征,一直是植物地理学的重要研究内容(孟婷婷等, 2007)。作为长期适应环境而发展出的相对稳定的特征,植物属性与其所处环境密切相关(Wright et al, 2005),并表现出一定的地理格局(Díaz et al, 2016),为植物地理分布格局及机制的研究提供了基础。在众多的植物属性中,与植物定植、存活、生长和死亡紧密相关的一系列核心植物属性称为植物功能属性(或植物功能性状),可用来解释植物个体、种群、群落和生态系统的生态功能(Violle et al, 2014)。植物功能属性和生态功能关系的研究成为植物地理学发展的重要动力之一。全球变化和生态保护研究的强烈需求在近年来推动着多时空尺度生态系统服务评估和预
测研究快速发展,有越来越多的研究关注植物属性的空间分布特征,并在不同空间尺度上将植物属性与环境联系起来,使植物属性地理学发展成为生物地理学新的研究方向(Tilman et al, 1997; Vile et al, 2006;Violle et al, 2014)。本文试图通过文献分析,总结植物属性和植物属性地理学的国际研究前沿,并对未来发展趋势进行展望,希望能促进我国植物属性地理学的发展。
近年来,随着植物属性标准测定手册的发表和完善(Cornelissen et al, 2003; Pérez-Harguindeguy et al, 2013),研究者们对全球多个区域的植物属性进行了规范的测定和整理(Díaz et al, 2004; Reich et al, 2004; Wright et al, 2004)。在进行属性地理学的研究时,首先应根据关注的科学问题和属性的生态学意义来选择适当的属性作为对象(Garnier et al, 2007)。
植物属性的生态学意义各有不同,目前最常用到的植物属性包括比叶面积(specific leaf area, SLA)、叶干物质含量(leaf dry matter content, LDMC)、叶片氮含量、种子重量、植物高度、茎密度等(Levine, 2016)。比叶面积是叶面积与对应叶片干重的比值,能够反映植物获取资源的能力,比叶面积较低的植物能更好地适应资源贫瘠和干旱的环境,比叶面积较高的植物保持体内营养物质的能力较强(Cornelissen et al, 2003)。叶干物质含量是叶干重与饱和鲜重的比值,能够反映植物生态行为差异及获取资源的能力,相对于叶面积来说更容易准确测量(Cornelissen et al, 2003)。植株高度可反映植物多方面的适应和平衡能力,在光资源为限制因子的生境里,植株高大的植物可以获取更多的光照,在群落中具有更强的竞争能力(Hodgson et al, 1999)。叶片中养分含量也是植物叶片的重要属性。植物叶片中养分含量的多少直接影响植物的生产能力和植物自身对胁迫的抵御能力(Cornelissen et al, 2003)。植物叶片氮含量还可以反映土壤的肥力状况(Sabaté et al, 1995),也是植物营养价值和喜食性的指示指标(Cingolani et al, 2005; Pérez-Harguindeguy et al, 2013)。许多研究表明植物碳和氮含量存在很强的耦合关系(任书杰等, 2006),碳氮比会影响植物体的物质循环速率,进而影响整个生态系统的生物地球化学循环(李金花等, 2003)。种子重量或种子大小是植物重要的繁殖属性,是种子传播能力与幼苗成苗能力权衡的结果(Qi et al, 2015)。
根据测定难易程度的不同,可以将植物属性分为两类：硬属性(hard traits)和软属性(soft traits)(Lavorel et al, 2002)。硬属性是与植物功能直接相关但相对难以测量的属性,例如最大光合速率,直接控制植物的相对生长速率,但相对不易测定(Reich et al, 1992)。软属性是指相对容易快速测定的属性,如叶面积大小、植株高度等。研究发现,某些“软属性”与“硬属性”显著相关,例如比叶面积和叶片氮含量与最大光合速率具有显著的正相关关系(Reich et al, 1992,1997;Wright et al, 2001)。基于此,大部分研究选取了软属性作为研究对象。尽管软属性与硬属性有一定的相关性,但两者不可完全替代,仍然需要加强对硬属性的研究(刘晓娟等, 2015)。
在借助属性分析植物对环境的响应时,人们最初关注的是叶片和物种水平(Díaz, Cabido, 2001; Díaz et al, 2004; Adler et al, 2004)。随着研究的深入,研究者们越来越认识到仅仅关注叶片和物种水平植物属性的变化是不够的。研究发现,在功能群水平,相同功能群植物存在相似的属性集合,可能会使这些植物对干扰的响应一致(Bai et al, 2004; Gamfeldt et al, 2008);在群落水平,由于物种间以及功能群间植物属性集合存在分异性,植物属性的生态位互补效应可能会对干扰(如草地利用)的影响起到缓冲作用(Loreau et al, 2001; Rusch et al, 2009; Schumacher et al, 2009)。因此在不同生命组建水平上对植物属性展开分析可能会获得新的认识(Zheng et al, 2010)。在群落水平对属性进行分析更能反映植物属性与生态系统功能间的关系,结合群落结构数据,可以将物种水平的植物功能属性向群落水平进行推算。其中群落平均属性和属性多样性(trait diversity)被越来越多的学者所关注(Petchey et al, 2002; Garnier et al, 2007; Mouchet et al, 2010)。
群落平均属性一般以物种在群落中的相对多度(或相对盖度、相对生物量)为权重对属性值进行加权平均(Garnier et al, 2004)。群落加权平均属性主要体现的是优势种的属性和策略(Mason et al, 2003; Mouillot et al, 2005)。属性多样性又称功能多样性(functional diversity),是指群落中所有植物的功能属性的数值、范围和分布(Lavorel et al, 2008)。有研究者建议从三个方面来综合评价属性多样性,包括功能丰富度(functional richness)、功能均匀度(functional evenness)和功能离散度(functional divergence)(Mason et al, 2005; Villéger et al, 2008)。由于属性多样性的计算方法一直在发展,新的数学方法和公式层出不穷,研究者需要根据科学问题的不同对属性多样性指数进行选择(Mouchet et al, 2010; Perronne et al, 2017)。广义上,群落加权平均属性也属于属性多样性的范畴。有研究者提出将群落平均属性与属性多样性二者结合,可以较为全面地对群落水平的属性特征进行研究(Garnier et al,2004; Ricotta et al, 2011)。近年来,这方面的研究开始逐渐开展(Pescador et al, 2016; Ali et al, 2017)。
植物通过调节属性来实现其对环境的适应,而属性之间的关系变化则靠植物对资源的权衡(Trade-off)来调控。植物属性的权衡关系研究包括对初级权衡关系(Fundamental Trade-offs)和次级权衡关系(Secondary Trade-offs)的探讨。初级权衡是指植物属性之间的内在关系,反映了植物构建功能属性的一种内在基本方式(Reich et al, 1992,1997; Suding et al, 2003)。初级权衡通常关注植物属性与属性之间的关系,最广为人知的初级权衡被称作“叶片经济型谱”(Wright et al, 2004)。Wright等(2004)对全球范围内2548种植物的6种重要属性进行了分析,发现生长快速、获取资源效率高的植物往往具有较高的比叶面积和叶片氮含量,以及较低的叶片干物质含量,这些植物占据经济型谱的一端;相反,生长缓慢、储存资源效率高的物种一般具有较高的叶片干物质含量,以及较低的比叶面积和叶片氮含量,它们分布在经济型谱的另一端(Díaz et al, 2004; Garnier et al, 2004)。最近,Díaz等(2016)对46085种维管植物与植物生存、生长、繁殖密切相关的6种属性进行了维度分析,发现有两个维度可以解释属性变异量的75%,其中之一是叶片经济型谱,而另一维度则与植物全株及其器官的大小有关。
次级权衡是指植物属性的集合对生物和非生物因子的响应,关于属性与环境梯度间关系的研究更关注次级权衡(Suding et al, 2003; Wright et al, 2005)。许多研究发现植物属性是预测植物对土地利用方式响应的有效指标。其中放牧干扰对植物叶片属性的影响受到较多关注(Díaz et al, 2007; Cruz et al, 2010),许多研究表明对放牧适应的物种在放牧后生长速度加快,比叶面积增大,植物氮含量增加。这些植物一般会具有高的比叶面积和低的叶片韧性,这些属性使得植株生长较快,同时也受到采食者的喜爱(Cingolani et al, 2005),而对放牧逃避的物种在放牧后,植株高度变矮、生长速度减缓、比叶面积降低(Adler et al, 2001)。王炜等(2000)发现植物在放牧等干扰下会出现植物个体小型化的现象,表现为植株变矮、叶片变小变窄、枝叶质地变硬等。叶片面积随着放牧强度的增大而变小,因为在给定叶质量下,叶片较大的植物更容易被啃食,而叶片较小的植物需要多次啃食。因此放牧逃避属性通常与较差的适口性相关,例如小的叶面积和高的干物质含量(Díaz, Noy-Meir, et al, 2001)。过度放牧也会使植物根冠比增加,使得植物从环境中获取资源和利用资源的策略发生改变(Westley, 1993; 王炜等, 2000)。此外,割草和弃耕等也会改变植物的属性。如果长期割草而又缺乏动物排泄物的补给,植物体中的氮含量会降低(Louault et al, 2005; Schönbach et al, 2011)。Garnier等(2004)发现植物的比叶面积和叶氮含量随着弃耕年限的增加而减小,叶片干物质含量的变化趋势则相反,存在明显的资源获取策略向资源储藏策略的转变。
Chapin等(2000)提出了通过植物属性来研究生态系统功能的框架。随后,有关植物属性和生态系统功能的研究迅速成为研究热点(Díaz, Cabido, 2001; Garnier et al, 2004; He et al, 2008; Kattge et al, 2011; Díaz et al, 2016)。随着物种功能属性分异性的增加,物种获取资源的方式更加多样,使得物种生态位重叠程度降低,有助于植物功能互补(functional complementarity)(Tilman, 1997)。许多研究通过量化物种之间属性的分布特征来计算属性多样性,表明功能属性的多样性与生态系统功能有着直接关系(Petchey et al, 2006; Mouchet et al, 2010)。
在生物多样性和生态系统功能关系的研究中,生态学家发现生态系统功能不仅与物种数目有关,还与物种的功能属性有关(Hooper et al, 1997)。群落水平的加权属性与生态系统功能联系紧密(Suding et al, 2008)。质量比假说(mass ratio hypothesis)认为某一时间点的生态系统功能是由占群落生物量比例大的优势种决定的(Grime, 1998)。基于这一假说,某些属性的群落加权平均值可以很好地预测一些生态系统功能,如地上净初级生产力、凋落物分解速率、土壤水分等(Cornelissen et al, 1996; Vile et al, 2006; Mokany et al, 2008; Fortunel et al, 2009)。在群落水平,群落平均属性的改变一方面来自于种内变异(Intraspecific Variability),另一方面来自于种间变异(Interspecific Variability)。不过,如果仅为了验证质量比假说,群落属性的变化是最重要的性质,不需要区分这一变化是由物种组成还是由属性变化引起的(Garnier et al, 2007)。
属性多样性体现了生态位互补假说(niche complementarity hypothesis)的思想,该假说主张植物属性可以调节生态位的分离,进而形成植物在空间中不同的资源利用策略(Petchey et al, 2006)。Tilman等(1997)发现生态系统功能属性的多样性越高,生态系统的稳定性越高;Dukes(2001)在微观实验中发现生态系统抵抗入侵的能力与物种丰富度没有关系,而与属性多样性的关系密切。土壤和水生系统的植物属性多样性可以提高系统捕获营养和光照资源的效率(Hodgson et al, 1996; Grime, 1997; Hooper et al, 1997; Tilman et al, 1997; Prieur-Richard et al, 2000; Nyström et al, 2001)。许多研究者通过比较分析发现在局部尺度的生态系统中,属性多样生态系统性比分类学多样性更重要,因为属性多样性可能是生态系统资源动态、稳定性和生产力的优良指示指标(Tilman, 2000; Díaz, Cabido, 2001; Cardinale et al, 2006; Díaz et al, 2007)。
大型数据库的建立有助于植物属性地理学的快速发展(Violle et al, 2014)。全球植物属性数据库(TRY)已有超过300个数据集(Kattge et al, 2011),其中不仅包括原始数据集,也包括综合性数据库,如西北欧植物区系属性数据库(LEDA)、全球植物属性网络数据库(GlopNet)等,汇聚了全球范围内93个数据库的植物属性数据,涵盖全球300000种植物中的69000种(Reich et al, 2007; Kleyer et al, 2008)。最近,根系数据库(Iversen et al, 2017)的发表弥补了其他数据库中植物地下部分属性较少的不足。我国的植物属性数据库也已发表并共享,目前包括来自122个样地的1215个物种(Wang et al, 2017),但该数据库中青藏高原地区的数据十分缺乏(He et al, 2006; Qi et al, 2015)。需要注意的是,属性数据库中的数据缺失在所难免,这种缺失不仅包括属性数据的缺失,更可能包括收录物种的缺失而导致的偏差,有研究者提出了针对性的检查和修正方法(Sandel et al, 2010)。
随着属性数据库的扩展,更加简单与规范的测量方法正在发展(Knevel et al, 2003; Wright et al, 2004),为植物属性的分布研究从点状向面状转换提供了可能。结合全球最大的植物属性数据库(TRY)(Kattge et al, 2011)和现代贝叶斯空间统计建模方法(Modern Bayesian Spatial Statistical Modeling Techniques),基于植物属性和环境因子之间的关系,研究者绘制了比叶面积、叶片氮、磷含量的全球分布图(Butler et al, 2017)。借助激光扫描和成像光谱技术,可以直接对区域植物功能属性多样性进行空间制图,研究发现属性丰富度随着面积的增大而呈指数增长,而功能均匀度和离散度则与面积无关,这项研究提出了对植物功能属性多样性进行空间计算的新方法(Schneider et al, 2017)。
多个综述总结了植物功能属性在环境梯度上的分布和变化规律 (孟婷婷等, 2007; 冯秋红等, 2008; 刘晓娟等, 2015)。从全球尺度到区域尺度,不同空间尺度植物属性的分布有不同的决定性影响因子(刘晓娟等, 2015)。物种水平的植物属性研究在不同的空间尺度上都有开展。由于群落水平的植物属性需要整合植物个体的属性数据和群落结构的数据,通常在小的空间尺度上进行,而全球尺度上群落属性的空间格局研究仍然受到一定限制 (Funk et al, 2017)。
在全球和区域尺度上,物种水平植物功能属性均存在非常明显的空间格局,这种空间格局是气候因子空间格局的反映。基于全球植物属性数据的分析展现了全球尺度植物功能属性的分布格局：在更干旱、更炎热、太阳辐射更强烈的地区,植物的比叶重和叶片氮含量更高(Wright et al, 2004, 2005);随着干旱和寒冷程度增加,森林将更多的生物量分配给根系(Reich, Luo, et al, 2014);从两极向赤道,随着年均温的升高和生长季的增长,植物的氮磷含量逐渐降低而氮磷比升高(Reich et al, 2004)。中国国家尺度的研究也表明植物功能属性的地理分布与气候因子有较好的关系(Han et al, 2005)。在中国不同地区沿环境因子梯度的研究也反映了植物功能属性与环境因子之间的关系：在青藏高原中部的东西长200 km的样带上,随着年平均温度的升高,植物的比叶重、单位面积的最大光合速率以及单位面积的氮含量增加,但这些属性随着年均降水量并没有显著的变化(He et al, 2006, 2018);随着寒冷程度的增加,中国东北森林植物比叶面积逐渐增加而叶片干物质含量随之降低(Wang et al, 2016);随着干旱程度的增加,中国温带草原样带不同功能群植物的形态、生理和解剖属性也呈现出明显的变化规律(Guo et al, 2017)。
群落水平的研究大体可以分为两类：海拔梯度的研究和水平梯度的研究。前者有两个经典的研究案例：青藏高原东北部高寒草甸群落平均种子质量和属性多样性随着海拔升高而下降(Qi et al,2015);乞力马扎罗山的植物群落在高降水量的海拔有更高的比叶面积、叶片氮含量、冠层高度、叶面积,同时有更低的叶片干物质含量(Schellenberger et al, 2017)。后者也有两个经典研究案例：地中海地区随干旱程度的增加一年生植物和风媒传播的植物比例增加,但群落平均最大高度降低、平均开花时间缩短,同时功能离散度普遍降低(Nunes et al, 2017);在美国,随着降雨量的增加,群落平均种子大小增大,叶片氮含量下降,叶片寿命升高(Sandel et al, 2010)。
植物属性研究的发展为全球变化影响下碳循环过程的模拟和陆面模式的发展带来新的机遇和挑战(Reich, Rich, et al, 2014)。传统的植物地理学是以物种为研究对象,21世纪植物地理学的巨大挑战之一则是将物种组成与生态功能与服务相联系,如用植物属性代替物种来解释世界上的物种多样性机制,并基于植物属性来预测未来全球气候变化下的物种迁移(Levine, 2016)。有研究表明裸子植物针叶属性的种间差异反映了其沿纬度梯度对温度和湿度的适应,该研究从植物属性出发进一步解释了植物分布和植物对环境适应的生理机制,为全球变化下的针叶林碳循环过程的精确模拟提供了可能性(Reich, Rich, et al, 2014)。地球科学模型直接关注在全球尺度下生物地球化学循环的变化,但在大多数情况下只用了极简化的生物多样性模式：少量的植物功能型和平均的生理生态学特征用来模拟模型中每个生物群区的生物地球化学循环过程对全球变化的响应(van Bodegom et al, 2014)。一个生态系统的物种组成是生态系统功能的关键驱动因子,生物多样性的功能组成,如形态和属性多样性,已被认为是生物多样性类型和生物地球化学循环之间的重要联系,而且也许是生态系统服务的核心驱动力(Violle et al, 2014),这将进一步推动全球变化对生物多样性和生态系统服务的模型模拟研究。
植物属性地理学在全球变化和地学研究中将起到重要作用,有助于更好地认识地球系统对全球变化的响应机制,为地球系统的可持续发展服务(Violle et al, 2014)。未来重点研究方向包括：
(1) 植物属性地理学研究手段的提升。目前植物属性地理学的研究方法还集中在属性测量的标准化、物种和群落水平属性的计算方法等基础研究上。通过遥感和GIS技术开展属性的空间连续表达研究刚刚兴起(Butler et al, 2017)。随着遥感科学技术的迅猛发展,借助激光扫描和成像光谱技术直接对区域植物功能属性多样性进行空间制图将是未来植物属性地理学的重要研究手段(Schneider et al, 2017; Su et al, 2017)。
(2) 植物属性的空间分异与环境因子之间的关系研究。在全球植被模型研究中,基于物种的植被动态模型发展为基于属性的植被动态模型有助于更加准确地认识植被在陆地生态系统能量流动、水和碳循环过程中的作用,是未来重要的研究内容(Suding et al, 2008; van Bodegom et al, 2014)。为了实现这一目标,认识全球植物属性的空间分异规律及其与环境因子之间的关系仍将是未来的重点。
(3) 植物属性数据库的完善。植物属性地理学的核心是揭示植物属性的空间分异规律及其影响机制(Kattge et al, 2011; Violle et al, 2014),这将有赖于区域乃至全球尺度的植物属性数据支持。无论是全球尺度还是区域尺度的数据库仍然是个案研究的汇总,缺少在植物地理分布规律的基础上进行顶层设计。基于顶层设计的国家和全球植物属性数据库的建设将是植物属性地理学发展的方向。
The authors have declared that no competing interests exist.
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植物功能性状对环境的响应及其应用 [J].Response of plant functional traits to environment and its application [J]. |
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不同放牧强度对冷蒿和星毛委陵菜养分含量的影响 [J].https://doi.org/10.3321/j.issn:1004-5759.2003.06.005 URL [本文引用: 1] 摘要
随放牧强度的增加,冷蒿叶(包括花)中全碳含量为41.16%35.75%,各处理间差异不显著;茎中全碳含量与叶中相似;根中全碳含量为39.16%33.15%。叶中全氮含量为2.28%1.60%,根中含量中牧最高(2.40%),无牧最低(1.35%),茎中含量各处理变化不明显,基本保持在1.50%。冷蒿叶中全磷含量随放牧强度增加而增加,茎中全磷含量轻度和中度放牧高于对照,而重度放牧显著低于对照,根中全磷含量随放牧强度的增加而增加,其中中度放牧增加显著。随放牧强度的增加,星毛委陵菜种群地上、地下部分全碳含量分别为34.34%38.06%,27.30%33.99%,处理间差异不显著。地上部分氮含量分别
Effect of different grazing intensities on the nutrient contents of Artemisia frigida and Potentilla acaulis [J].https://doi.org/10.3321/j.issn:1004-5759.2003.06.005 URL [本文引用: 1] 摘要
随放牧强度的增加,冷蒿叶(包括花)中全碳含量为41.16%35.75%,各处理间差异不显著;茎中全碳含量与叶中相似;根中全碳含量为39.16%33.15%。叶中全氮含量为2.28%1.60%,根中含量中牧最高(2.40%),无牧最低(1.35%),茎中含量各处理变化不明显,基本保持在1.50%。冷蒿叶中全磷含量随放牧强度增加而增加,茎中全磷含量轻度和中度放牧高于对照,而重度放牧显著低于对照,根中全磷含量随放牧强度的增加而增加,其中中度放牧增加显著。随放牧强度的增加,星毛委陵菜种群地上、地下部分全碳含量分别为34.34%38.06%,27.30%33.99%,处理间差异不显著。地上部分氮含量分别
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植物功能性状研究进展 [J].Plant functional traits-concepts, applications and future directions [J]. |
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植物功能性状与环境和生态系统功能 [J].Plant functional traits, environments and ecosystem functioning [J]. |
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陆地生态系统氮状态对碳循环的限制作用研究进展 [J].https://doi.org/10.3969/j.issn.1007-6301.2006.04.007 URL [本文引用: 1] 摘要
陆地生态系统碳循环和氮循环密切相关，碳贮量与碳通量在很大程度上受氮循环的影响和限制。由 于氮循环的复杂性，在以往的大多数碳循环研究中，更多考虑水分、温度和大气CO2浓度等因子的影响．考虑碳氮相互作用的研究较少。氮素可限制植物光合、有 机质分解、同化产物的分配以及生态系统对大气CO2浓度升高的响应。根据目前有关碳氮模型的发展状况可将碳氮耦合循环模型分为三大类：一是静态模型，它的 土壤养分水平或者叶氮含量不变，是常数，这类模型适合于在站点或氮素浓度变化不大的区域应用：二是土壤氮限制模型，能够保持稳定的生态系统氮收支．在 NPP（NetPrimary Productivitv，净初级生产力）的模拟中考虑土壤氮有效性的动态变化的影响，使模拟结果更为合理：三是叶氮限制模型。在NPP的模拟中考虑叶片 氮浓度的动态变化的影响。这三类模型虽然都考虑了氮对碳循环的限制作用，但在氮碳循环机理方面尚有不少欠缺．所以在研究中可能会带来很大的不确定性。在以 后的研究中，应通过加强碳氮相互作用的实验研究．增进对碳氮过程的深入了解．进而建立综合动态的碳氮耦合模型，以减少目前碳循环研究中的不确定性。
The effects of nitrogen limitation on terrestrial ecosystem carbon cycle: A review [J].https://doi.org/10.3969/j.issn.1007-6301.2006.04.007 URL [本文引用: 1] 摘要
陆地生态系统碳循环和氮循环密切相关，碳贮量与碳通量在很大程度上受氮循环的影响和限制。由 于氮循环的复杂性，在以往的大多数碳循环研究中，更多考虑水分、温度和大气CO2浓度等因子的影响．考虑碳氮相互作用的研究较少。氮素可限制植物光合、有 机质分解、同化产物的分配以及生态系统对大气CO2浓度升高的响应。根据目前有关碳氮模型的发展状况可将碳氮耦合循环模型分为三大类：一是静态模型，它的 土壤养分水平或者叶氮含量不变，是常数，这类模型适合于在站点或氮素浓度变化不大的区域应用：二是土壤氮限制模型，能够保持稳定的生态系统氮收支．在 NPP（NetPrimary Productivitv，净初级生产力）的模拟中考虑土壤氮有效性的动态变化的影响，使模拟结果更为合理：三是叶氮限制模型。在NPP的模拟中考虑叶片 氮浓度的动态变化的影响。这三类模型虽然都考虑了氮对碳循环的限制作用，但在氮碳循环机理方面尚有不少欠缺．所以在研究中可能会带来很大的不确定性。在以 后的研究中，应通过加强碳氮相互作用的实验研究．增进对碳氮过程的深入了解．进而建立综合动态的碳氮耦合模型，以减少目前碳循环研究中的不确定性。
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草原群落退化与恢复演替中的植物个体行为分析 [J].https://doi.org/10.1088/0256-307X/17/9/008 URL [本文引用: 2] 摘要
定义植物个体小型化是在草原过度放牧条件下 ,草原植物植株变矮 ,叶片变短、变窄 ,节间缩短 ,以及根系分布浅层化等性状的集合。小型化个体的生态学属性介于环境饰变与生态型之间 ,特称之为扰动响应型。个体小型化逆转过程表现出集体行为 ;小型化个体具有维持其形状的保守性 ,变化的阶段性和突变性 ;小型化的逆过程即正常化过程 ,与演替时间有关。个体小型化是过度放牧下群落生产力衰退的重要表现 ,是对过度放牧的负反馈机制。在草原群落退化演替机理研究中 ,对个体小型化的深入认识是十分重要的环节。
Analysis of the plant individual behaviour during the degradation and restoring succession in steppe community [J].https://doi.org/10.1088/0256-307X/17/9/008 URL [本文引用: 2] 摘要
定义植物个体小型化是在草原过度放牧条件下 ,草原植物植株变矮 ,叶片变短、变窄 ,节间缩短 ,以及根系分布浅层化等性状的集合。小型化个体的生态学属性介于环境饰变与生态型之间 ,特称之为扰动响应型。个体小型化逆转过程表现出集体行为 ;小型化个体具有维持其形状的保守性 ,变化的阶段性和突变性 ;小型化的逆过程即正常化过程 ,与演替时间有关。个体小型化是过度放牧下群落生产力衰退的重要表现 ,是对过度放牧的负反馈机制。在草原群落退化演替机理研究中 ,对个体小型化的深入认识是十分重要的环节。
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The effect of grazing on the spatial heterogeneity of vegetation [J].https://doi.org/10.1007/s004420100737 URL PMID: 28547391 [本文引用: 1] 摘要
Abstract Grazing can alter the spatial heterogeneity of vegetation, influencing ecosystem processes and biodiversity. Our objective was to identify why grazing causes increases in the spatial heterogeneity of vegetation in some cases, but decreases in others. The immediate effect of grazing on heterogeneity depends on the interaction between the spatial pattern of grazing and the pre-existing spatial pattern of vegetation. Depending on the scale of observation and on the factors that determine animal distribution, grazing patterns may be stronger or weaker than vegetation patterns, or may mirror the spatial structure of vegetation. For each possible interaction between these patterns, we make a prediction about resulting changes in the spatial heterogeneity of vegetation. Case studies from the literature support our predictions, although ecosystems characterized by strong plant-soil interactions present important exceptions. While the processes by which grazing causes increases in heterogeneity are clear, how grazing leads to decreases in heterogeneity is less so. To explore how grazing can consistently dampen the fine-scale spatial patterns of competing plant species, we built a cell-based simulation model that features two competing plant species, different grazing patterns, and different sources of vegetation pattern. Only the simulations that included neighborhood interactions as a source of vegetation pattern produced results consistent with the predictions we derived from the literature review.
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Functional traits of graminoids in semi-arid steppes: A test of grazing histories [J].https://doi.org/10.1111/j.0021-8901.2004.00934.x URL [本文引用: 1] 摘要
1. Understanding variability in ecosystem response to grazing is essential for improving management. Recent efforts have focused on the role of plant functional traits but do not identify factors influencing trait development. As traits are legacies of historical selective pressures, they may indicate the importance of a plant community's evolutionary history of grazing.2. We compared grazing-resistance traits of graminoids collected in the Patagonian steppe of Argentina, presumed to have a long evolutionary history of grazing, and the sagebrush steppe of the north-western USA, known to have a short grazing history. The purpose of this comparison was to test the influence of grazing history and aridity on resistance traits, and to generate predictions about the vulnerability of these ecosystems to grazing impacts. We measured both morphology and leaf chemical composition on common species from an arid and a semi-arid site in each region, then performed a principal components analysis on the species-by-traits matrix.3. The first axis of the ordination was correlated with measures of forage quality such as leaf tensile strength, fibre and nitrogen content, while the second axis was correlated with plant stature. The dominant species from the drier Patagonia site scored significantly lower on the first axis (lower forage quality) than dominants from the sagebrush steppe. Plants from the wetter Patagonia site were intermediate in forage quality. Sagebrush steppe species scored significantly higher on the second axis (taller) but this difference was not significant when we considered only dominant species.4. The intercontinental differences in plant traits are consistent with evidence indicating a longer evolutionary history of grazing in Patagonia. Differences in traits between the dry and wet sites in Patagonia are consistent with the hypothesis that aridity promotes grazing resistance, although trait contrasts between the drier and wetter sagebrush sites were not sign
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Community-weighted mean of leaf traits and divergence of wood traits predict aboveground biomass in secondary subtropical forests [J].https://doi.org/10.1016/j.scitotenv.2016.09.022 URL PMID: 27657991 [本文引用: 1] 摘要
Subtropical forests are globally important in providing ecological goods and services, but it is not clear whether functional diversity and composition can predict aboveground biomass in such forests. We hypothesized that high aboveground biomass is associated with high functional divergence (FDvar, i.e., niche complementarity) and community-weighted mean (CWM, i.e., mass ratio; communities dominated by a single plant strategy) of trait values. Structural equation modeling was employed to determine the direct and indirect effects of stand age and the residual effects of CWM and FDvar on aboveground biomass across 31 plots in secondary forests in subtropical China. The CWM model accounted for 78, 20, 6 and 2% of the variation in aboveground biomass, nitrogen concentration in young leaf, plant height and specific leaf area of young leaf, respectively. The FDvar model explained 74, 13, 7 and 0% of the variation in aboveground biomass, plant height, twig wood density and nitrogen concentration in young leaf, respectively. The variation in aboveground biomass, CWM of leaf nitrogen concentration and specific leaf area, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf explained by the joint model was 86, 20, 13, 7, 2 and 0%, respectively. Stand age had a strong positive direct effect but low indirect positive effects on aboveground biomass. Aboveground biomass was negatively related to CWM of nitrogen concentration in young leaf, but positively related to CWM of specific leaf area of young leaf and plant height, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf. Leaf and wood economics spectra are decoupled in regulating the functionality of forests, communities with diverse species but high nitrogen conservative and light acquisitive strategies result in high aboveground biomass, and hence, supporting both the mass ratio and niche complementarity hypotheses in secondary subtropical forests.
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| [11] |
Ecosystem stability and compensatory effects in the Inner Mongolia grassland [J].https://doi.org/10.1038/nature02850 URL PMID: 202020202020202020202020 [本文引用: 1] 摘要
Nature is the international weekly journal of science: a magazine style journal that publishes full-length research papers in all disciplines of science, as well as News and Views, reviews, news, features, commentaries, web focuses and more, covering all branches of science and how science impacts upon all aspects of society and life.
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| [12] |
Mapping local and global variability in plant trait distributions [J].https://doi.org/10.1073/pnas.1708984114 URL PMID: 29196525 [本文引用: 2] 摘要
Abstract Our ability to understand and predict the response of ecosystems to a changing environment depends on quantifying vegetation functional diversity. However, representing this diversity at the global scale is challenging. Typically, in Earth system models, characterization of plant diversity has been limited to grouping related species into plant functional types (PFTs), with all trait variation in a PFT collapsed into a single mean value that is applied globally. Using the largest global plant trait database and state of the art Bayesian modeling, we created fine-grained global maps of plant trait distributions that can be applied to Earth system models. Focusing on a set of plant traits closely coupled to photosynthesis and foliar respiration-specific leaf area (SLA) and dry mass-based concentrations of leaf nitrogen ([Formula: see text]) and phosphorus ([Formula: see text]), we characterize how traits vary within and among over 50,000 [Formula: see text]-km cells across the entire vegetated land surface. We do this in several ways-without defining the PFT of each grid cell and using 4 or 14 PFTs; each model's predictions are evaluated against out-of-sample data. This endeavor advances prior trait mapping by generating global maps that preserve variability across scales by using modern Bayesian spatial statistical modeling in combination with a database over three times larger than that in previous analyses. Our maps reveal that the most diverse grid cells possess trait variability close to the range of global PFT means.
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| [13] |
Effects of biodiversity on the functioning of trophic groups and ecosystems [J].https://doi.org/10.1038/nature05202 URL PMID: 17066035 [本文引用: 1] 摘要
Over the past decade, accelerating rates of species extinction have prompted an increasing number of studies to reduce species diversity experimentally and examine how this alters the efficiency by which communities capture resources and convert those into biomass. So far, the generality of patterns and processes observed in individual studies have been the subjects of considerable debate. Here we present a formal meta-analysis of studies that have experimentally manipulated species diversity to examine how it affects the functioning of numerous trophic groups in multiple types of ecosystem. We show that the average effect of decreasing species richness is to decrease the abundance or biomass of the focal trophic group, leading to less complete depletion of resources used by that group. At the same time, analyses reveal that the standing stock of, and resource depletion by, the most species-rich polyculture tends to be no different from that of the single most productive species used in an experiment. Of the known mechanisms that might explain these trends, results are most consistent with what is called the 'sampling effect', which occurs when diverse communities are more likely to contain and become dominated by the most productive species. Whether this mechanism is widespread in natural communities is currently controversial. Patterns we report are remarkably consistent for four different trophic groups (producers, herbivores, detritivores and predators) and two major ecosystem types (aquatic and terrestrial). Collectively, our analyses suggest that the average species loss does indeed affect the functioning of a wide variety of organisms and ecosystems, but the magnitude of these effects is ultimately determined by the identity of species that are going extinct.
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| [14] |
Consequences of changing biodiversity [J].https://doi.org/10.1038/35012241 URL [本文引用: 1] |
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Plant functional traits, herbivore selectivity and response to sheep grazing in Patagonian steppe grasslands [J].https://doi.org/10.1111/j.1365-2664.2004.00978.x URL [本文引用: 2] 摘要
Summary Top of page Summary Introduction Materials and methods Results Discussion Acknowledgements References 1 In some ecosystems there is a positive feedback between forage quality and grazing intensity. This involves three components of plant tolerance to grazing: functional traits, herbivore selectivity and response to grazing. We analysed the relationships between these components at species and community levels in Patagonian steppe grasslands. 2 We measured plant functional traits [height, specific leaf area (SLA) and foliar toughness] and estimated sheep selectivity and grazing response indices for 35 plant species. Sheep selectivity indices were obtained from microhistological and species availability data, and grazing response indices from species abundances in sites with contrasting grazing intensities. We performed correlations and multiple regressions among the three types of variables across the pool of 35 species. 3 To analyse data at the community level, we computed weighted averages of traits and sheep selectivity indices for 34 floristic samples taken from each side of 17 fence lines with contrasting grazing intensities. Correlations between mean trait values and sheep selectivity across the 34 samples, and paired comparisons of those variables between sides of the fences, were performed. 4 Taller plants had leaves with lower SLA and/or higher toughness. Short species of intermediate toughness were selected more often by sheep, while SLA was not related to sheep selectivity. Short species with high SLA increased with grazing, while toughness and sheep selectivity were unrelated to grazing response. 5 At the community level, short swards with high average SLA had high selectivity indices and were more abundant on the most intensively grazed sides of fence lines. Leaf toughness was unrelated to other traits or to sheep selectivity, and showed no significant response to grazing. 6 Synthesis and applications . Intensive grazing can increase the forage value of grasslands by the creation of lawns dominated by tolerant species. However, results from this study showed that some plant species that were avoided by grazers also increased, indicating a potential risk of a shift in composition of grazing lawns towards states of low forage value. This suggests that periodic resting of lawns could be a good management strategy to favour palatable species, thereby minimizing the risk of undesirable shifts in the overall species composition.
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| [16] |
Seedling growth, allocation and leaf attributes in a wide range of woody plant species and types [J].https://doi.org/10.2307/2261337 URL [本文引用: 1] 摘要
1 Innate mean relative growth rate (mean RGR) of seedlings is a key attribute for the performance of species in their natural habitats. This study aimed firstly at identifying easily measurable correlates of mean RGR of temperate zone woody species. Secondly, it tested the hypothesis that functional groups of woody plants could be characterized by their mean RGR and associated allocation and leaf attributes. 2 In a standardized experiment, 80 woody species from the British Isles and North Spain, ranging widely in leaf habit and life-form, were screened for seed weight and potential seedling mean relative growth rate (RGR), biomass allocation and leaf attributes. 3 Mean RGR, when based on plant weights excluding any attached thick cotyledons, was linearly and closely correlated with leaf area ratio (LAR, total leaf area/plant dry weight) and one of the two components of LAR, specific leaf area (SLA, leaf area/leaf dry weight). The other component, leaf weight fraction (leaf weight/plant dry weight), was only correlated with mean RGR when based upon true leaves, disregarding leafy cotyledons. These relationships were also demonstrated when taxonomic relatedness was accounted for. 4 The data supported the hypothesis that differentiation, as seen among functional groups of species in terms of leaf habit and life-form, corresponded with differentiation in mean RGR and other seedling attributes. For instance, deciduous species grew consistently faster than evergreens. 5 When SLA was split into its two components, specific saturated leaf area (SSLA, total leaf area/total saturated leaf weight) and leaf saturated weight/dry weight ratio (SW/DW), it was found that SSLA was consistently smaller in evergreens than in deciduous species, both for sclerophyllous and succulent leaves. Among species of the same leaf habit, variation in SLA among life-forms could be explained by variation in leaf SW/DW. 6 SSLA and leaf SW/DW, both easy to measure, together could help to categorize growth rate within the evergreen or deciduous species. This may be useful in vegetation monitoring. 7 The data may provide useful predictive tools to infer potential growth rates and nutrient conservation strategies of real vegetation from the functional attributes and composition of its functional species groups.
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| [17] |
A handbook of protocols for standardised and easy measurement of plant functional traits worldwide [J].https://doi.org/10.1080/14786430802620724 URL [本文引用: 4] 摘要
There is growing recognition that classifying terrestrial plant species on the basis of their function ( into 'functional types') rather than their higher taxonomic identity, is a promising way forward for tackling important ecological questions at the scale of ecosystems, landscapes or biomes. These questions include those on vegetation responses to and vegetation effects on, environmental changes ( e. g. changes in climate, atmospheric chemistry, land use or other disturbances). There is also growing consensus about a shortlist of plant traits that should underlie such functional plant classifications, because they have strong predictive power of important ecosystem responses to environmental change and/or they themselves have strong impacts on ecosystem processes. The most favoured traits are those that are also relatively easy and inexpensive to measure for large numbers of plant species. Large international research efforts, promoted by the IGBP-GCTE Programme, are underway to screen predominant plant species in various ecosystems and biomes worldwide for such traits. This paper provides an international methodological protocol aimed at standardising this research effort, based on consensus among a broad group of scientists in this field. It features a practical handbook with step-by-step recipes, with relatively brief information about the ecological context, for 28 functional traits recognised as critical for tackling large-scale ecological questions.
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| [18] |
Leaf traits as functional descriptors of the intensity of continuous grazing in native grasslands in the south of brazil [J].https://doi.org/10.2111/08-016.1 URL [本文引用: 1] 摘要
La noción de grupos funcionales de plantas (GFP) ha sido utilizada para describir la respuesta de la vegetación nativa a los factores del medio (fertilidad) y al disturbio del pastoreo, pero pocos de dichos estudios han sido conducidos bajo condiciones de pastoreo continuo. En el presente trabajo se trata de verificar si dicho enfoque puede utilizarse para analizar la respuesta de la comunidad a un gradiente de presión de pastoreo continuo. Al término de 15 a09os de diferenciación continua de la presión de pastoreo ejercida sobre una pradera nativa, se midió el contenido de materia seca foliar (CMSF) y el área foliar específica (AFE) de las poblaciones de gramíneas presentes en la comunidad. El gradiente de pastoreo fue establecido según los niveles de oferta de forraje: 4, 8, 12, y 16kg de materia seca por 100kg de peso vivo por día, oferta ajustada mensualmente. Los GFP fueron definidos según un análisis numérico, donde un algoritmo identifica un subgrupo óptimo de características basado en la correspondencia entre matrices de [especies × atributos]; [praderas × biomasa de gramíneas] y variables como los niveles de oferta de forraje y características del suelo. Los resultados muestran que es posible describir el gradiente de presión de pastoreo en base a alCMSF y/o el AFE medidas sobre las gramíneas que contribuyen al menos el 80% de la biomasa total de gramíneas. Cuatro GFP fueron identificados gracias a dichos atributos. Los GFP que presentan bajo CMSF y alto AFE son característicos de altas intensidades de uso de la pradera donde dominan las especies estoloníferas las cuales típicamente disponen de estrategias de captura rápida de recursos. Por el contrario, los PFT caracterizados por altos CMSF y bajos AFE contienen especies representativas de situaciones con bajo nivel de presión de pastoreo. Las variaciones en los valores de los atributos ponderados son originadas por cambios en la proporción de especies y no por una adaptación del tama09o de las hojas como fue supuesto. Se concluye que en ausencia de un gradiente de fertilidad, las plantas con estrategia de captura rápida de recursos están mejor representadas en situaciones donde la presión de pastoreo es excesiva. Esta situación conduce a una pérdida de la diversidad funcional, pero sobre todo a una reducción de la disponibilidad forrajera a niveles incompatibles con una producción animal alta.
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| [19] |
Vive la différence: Plant functional diversity matters to ecosystem processes [J].https://doi.org/10.1017/S0007114508971324 URL [本文引用: 1] 摘要
The links between plant diversity and ecosystem functioning remain highly controversial. There is a growing consensus, however, that functional diversity, or the value and range of species traits, rather than species numbers per se , strongly determines ecosystem functioning. Despite its importance, and the fact that species diversity is often an inadequate surrogate, functional diversity has been studied in relatively few cases. Approaches based on species richness on the one hand, and on functional traits and types on the other, have been extremely productive in recent years, but attempts to connect their findings have been rare. Crossfertilization between these two approaches is a promising way of gaining mechanistic insight into the links between plant diversity and ecosystem processes and contributing to practical management for the conservation of diversity and ecosystem services.
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| [20] |
The plant traits that drive ecosystems: Evidence from three continents [J].https://doi.org/10.1111/j.1654-1103.2004.tb02266.x URL [本文引用: 3] 摘要
Abstract Question: A set of easily-measured (‘soft’) plant traits has been identified as potentially useful predictors of ecosystem functioning in previous studies. Here we aimed to discover whether the screening techniques remain operational in widely contrasted circumstances, to test for the existence of axes of variation in the particular sets of traits, and to test for their links with ‘harder’ traits of proven importance to ecosystem functioning. Location: central-western Argentina, central England, northern upland Iran, and north-eastern Spain. Recurrent patterns of ecological specialization: Through ordination of a matrix of 640 vascular plant taxa by 12 standardized traits, we detected similar patterns of specialization in the four floras. The first PCA axis was identified as an axis of resource capture, usage and release. PCA axis 2 appeared to be a size-related axis. Individual PCA for each country showed that the same traits remained valuable as predictors of resource capture and utilization in all of them, despite their major differences in climate, biogeography and land-use. The results were not significantly driven by particular taxa: the main traits determining PCA axis 1 were very similar in eudicotyledons and monocotyledons and Asteraceae, Fabaceae and Poaceae. Links between recurrent suites of ‘soft’ traits and ‘hard’ traits: The validity of PCA axis 1 as a key predictor of resource capture and utilization was tested by comparisons between this axis and values of more rigorously established predictors (‘hard’ traits) for the floras of Argentina and England. PCA axis 1 was correlated with variation in relative growth rate, leaf nitrogen content, and litter decomposition rate. It also coincided with palatability to model generalist herbivores. Therefore, location on PCA axis 1 can be linked to major ecosystem processes in those habitats where the plants are dominant. Conclusion: We confirm the existence at the global scale of a major axis of evolutionary specialization, previously recognised in several local floras. This axis reflects a fundamental trade-off between rapid acquisition of resources and conservation of resources within well-protected tissues. These major trends of specialization were maintained across different environmental situations (including differences in the proximate causes of low productivity, i.e. drought or mineral nutrient deficiency). The trends were also consistent across floras and major phylogenetic groups, and were linked with traits directly relevant to ecosystem processes.
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| [21] |
The global spectrum of plant form and function [J].https://doi.org/10.1038/nature16489 URL PMID: 26700811 [本文引用: 2] 摘要
Abstract Earth is home to a remarkable diversity of plant forms and life histories, yet comparatively few essential trait combinations have proved evolutionarily viable in today's terrestrial biosphere. By analysing worldwide variation in six major traits critical to growth, survival and reproduction within the largest sample of vascular plant species ever compiled, we found that occupancy of six-dimensional trait space is strongly concentrated, indicating coordination and trade-offs. Three-quarters of trait variation is captured in a two-dimensional global spectrum of plant form and function. One major dimension within this plane reflects the size of whole plants and their parts; the other represents the leaf economics spectrum, which balances leaf construction costs against growth potential. The global plant trait spectrum provides a backdrop for elucidating constraints on evolution, for functionally qualifying species and ecosystems, and for improving models that predict future vegetation based on continuous variation in plant form and function.
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| [22] |
Plant trait responses to grazing- a global synthesis [J].https://doi.org/10.1016/j.atmosenv.2008.03.012 URL [本文引用: 2] 摘要
Herbivory by domestic and wild ungulates is a major driver of global vegetation dynamics. However, grazing is not considered in dynamic global vegetation models, or more generally in studies of the effects of environmental change on ecosystems at regional to global scale. An obstacle to this is a lack of empirical tests of several hypotheses linking plant traits with grazing. We, therefore, set out to test whether some widely recognized trait responses to grazing are consistent at the global level. We conducted a meta-analysis of plant trait responses to grazing, based on 197 studies from all major regions of the world, and using six major conceptual models of trait response to grazing as a framework. Data were available for seven plant traits: life history, canopy height, habit, architecture, growth form (forb, graminoid, herbaceous legume, woody), palatability, and geographic origin. Covariates were precipitation and evolutionary history of herbivory. Overall, grazing favoured annual over perennial plants, short plants over tall plants, prostrate over erect plants, and stoloniferous and rosette architecture over tussock architecture. There was no consistent effect of grazing on growth form. Some response patterns were modified by particular combinations of precipitation and history of herbivory. Climatic and historical contexts are therefore essential for understanding plant trait responses to grazing. Our study identifies some key traits to be incorporated into plant functional classifications for the explicit consideration of grazing into global vegetation models used in global change research. Importantly, our results suggest that plant functional type classifications and response rules need to be specific to regions with different climate and herbivory history.
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| [23] |
Can grazing response of herbaceous plants be predicted from simple vegetative traits [J].https://doi.org/10.1046/j.1365-2664.2001.00635.x URL [本文引用: 3] 摘要
1. Range management is based on the response of plant species and communities to grazing intensity. The identification of easily measured plant functional traits that consistently predict grazing response in a wide spectrum of rangelands would be a major advance. 2. Sets of species from temperate subhumid upland grasslands of Argentina and Israel, grazed by cattle, were analysed to find out whether: (i) plants with contrasting grazing responses differed in terms of easily measured vegetative and life-history traits; (ii) their grazing response could be predicted from those traits; (iii) these patterns differed between the two countries. Leaf mass, area, specific area (SLA) and toughness were measured on 83 Argentine and 19 Israeli species. Species were classified by grazing response (grazing-susceptible or grazing-resistant) and plant height ( 40 cm) as well as by life history (annual or perennial) and taxonomy (monocotyledon or dicotyledon). 3. Similar plant traits were associated with a specific response to grazing in both Argentina and Israel. Grazing-resistant species were shorter in height, and had smaller, more tender, leaves, with higher SLA than grazing-susceptible species. Grazing resistance was associated with both avoidance traits (small height and leaf size) and tolerance traits (high SLA). Leaf toughness did not contribute to grazing resistance and may be related to selection for canopy dominance. 4. Plant height was the best single predictor of grazing response, followed by leaf mass. The best prediction of species grazing response was achieved by combining plant height, life history and leaf mass. SLA was a comparatively poor predictor of grazing response. 5. The ranges of plant traits, and some correlation patterns between them, differed markedly between species sets from Argentina and Israel. However, the significant relationships between plant traits and grazing response were maintained. 6. The results of this exploratory study suggest
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| [24] |
Biodiversity and invasibility in grassland microcosms [J].https://doi.org/10.1007/s004420000549 URL PMID: 28547241 [本文引用: 1] 摘要
In the years since Charles Elton proposed that more diverse communities should be less susceptible to invasion by exotic species, empirical studies have both supported and refuted Elton's hypothesis. Here, I use grassland community microcosms to test the effect of functional diversity on the success of an invasive annual weed ( Centaurea solstitialis L.). I found that high functional diversity reduced the success of Centaurea by reducing resource availability. An equally important, but unstudied, question is whether diversity can buffer a community against the impacts of invasive species. In this experiment, although species diversity (independent of functional diversity) did not affect the success of the invader, the invader suppressed growth of species-poor communities more strongly. Invasion of Centaurea also increased summer evapotranspiration in species-poor communities. These results suggest that loss of species diversity alone does not affect community invasibility, but that communities with fewer species may be more likely to decline as a consequence of invasion.
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| [25] |
Leaf traits capture the effects of land use changes and climate on litter decomposability of grasslands across Europe [J].https://doi.org/10.1890/08-0418.1 URL PMID: 19341132 [本文引用: 1] 摘要
Land use and climate changes induce shifts in plant functional diversity and community structure, thereby modifying ecosystem processes. This is particularly true for litter decomposition, an essential process in the biogeochemical cycles of carbon and nutrients. In this study, we asked whether changes in functional traits of living leaves in response to changes in land use and climate were related to rates of litter potential decomposition, hereafter denoted litter decomposability, across a range of 10 contrasting sites. To disentangle the different control factors on litter decomposition, we conducted a microcosm experiment to determine the decomposability under standard conditions of litters collected in herbaceous communities from Europe and Israel. We tested how environmental factors (disturbance and climate) affected functional traits of living leaves and how these traits then modified litter quality and subsequent litter decomposability. Litter decomposability appeared proximately linked to initial litter quality, with particularly clear negative correlations with lignin-dependent indices (litter lignin concentr tion, lignin:nitrogen ratio, and fiber component). Litter quality was directly related to community-weighted mean traits. Lignin-dependent indices of litter quality were positively correlated with community-weighted mean leaf dry matter content (LDMC), and negatively correlated with community-weighted mean leaf nitrogen concentration (LNC). Consequently, litter decomposability was correlated negatively with community-weighted mean LDMC, and positively with community-weighted mean LNC. Environmental factors (disturbance and climate) influenced community-weighted mean traits. Plant communities experiencing less frequent or less intense disturbance exhibited higher community-weighted mean LDMC, and therefore higher litter lignin content and slower litter decomposability. LDMC therefore appears as a powerful marker of both changes in land use and of the pace of nutrient cycling across 10 contrasting sites.
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| [26] |
Revisiting the Holy Grail: Using plant functional traits to understand ecological processes [J].https://doi.org/10.1111/brv.12275 URL PMID: 27103505 [本文引用: 1] 摘要
ABSTRACT One of ecology's grand challenges is developing general rules to explain and predict highly complex systems. Understanding and predicting ecological processes from species' traits has been considered a oly Grail in ecology. Plant functional traits are increasingly being used to develop mechanistic models that can predict how ecological communities will respond to abiotic and biotic perturbations and how species will affect ecosystem function and services in a rapidly changing world; however, significant challenges remain. In this review, we highlight recent work and outstanding questions in three areas: ( i ) selecting relevant traits; ( ii ) describing intraspecific trait variation and incorporating this variation into models; and ( iii ) scaling trait data to community- and ecosystem-level processes. Over the past decade, there have been significant advances in the characterization of plant strategies based on traits and trait relationships, and the integration of traits into multivariate indices and models of community and ecosystem function. However, the utility of trait-based approaches in ecology will benefit from efforts that demonstrate how these traits and indices influence organismal, community, and ecosystem processes across vegetation types, which may be achieved through meta-analysis and enhancement of trait databases. Additionally, intraspecific trait variation and species interactions need to be incorporated into predictive models using tools such as Bayesian hierarchical modelling. Finally, existing models linking traits to community and ecosystem processes need to be empirically tested for their applicability to be realized.
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| [27] |
Multiple functions increase the importance of biodiversity for overall ecosystem functioning [J].https://doi.org/10.1890/06-2091.1 URL PMID: 18543617 [本文引用: 1] 摘要
Biodiversity is proposed to be important for the rate of ecosystem functions. Most biodiversity-ecosystem function studies, however, consider only one response variable at a time, and even when multiple variables are examined they are analyzed separately. This means that a very important aspect of biodiversity is overlooked: the possibility for different species to carry out different functions at any one time. We propose a conceptual model to explore the effects of species loss on overall ecosystem functioning, where overall functioning is defined as the joint effect of many ecosystem functions. We show that, due to multifunctional complementarity among species, overall functioning is more susceptible to species loss than are single functions. Modeled relationships between species richness and overall ecosystem functioning using five empirical data sets on monocultures reflected the range of effects of species loss on multiple functions predicted by the model. Furthermore, an exploration of the correlations across functions and the degree of redundancy within functions revealed that multifunctional redundancy was generally lower than single-function redundancy in these empirical data sets. We suggest that by shifting the focus to the variety of functions maintained by a diversity of species, the full importance of biodiversity for the functioning of ecosystems can be uncovered. Our results are thus important for conservation and management of biota and ecosystem services.
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| [28] |
Plant functional markers capture ecosystem properties during secondary succession [J].https://doi.org/10.1890/03-0799 URL [本文引用: 3] |
| [29] |
Assessing the effects of land-use change on plant traits, communities and ecosystem functioning in grasslands: A standardized methodology and lessons from an application to 11 European plots [J].https://doi.org/10.1093/aob/mcl215 URL PMID: 17085470 [本文引用: 3] 摘要
Abstract BACKGROUND AND AIMS: A standardized methodology to assess the impacts of land-use changes on vegetation and ecosystem functioning is presented. It assumes that species traits are central to these impacts, and is designed to be applicable in different historical, climatic contexts and local settings. Preliminary results are presented to show its applicability. METHODS: Eleven sites, representative of various types of land-use changes occurring in marginal agro-ecosystems across Europe and Israel, were selected. Climatic data were obtained at the site level; soil data, disturbance and nutrition indices were described at the plot level within sites. Sixteen traits describing plant stature, leaf characteristics and reproductive phase were recorded on the most abundant species of each treatment. These data were combined with species abundance to calculate trait values weighed by the abundance of species in the communities. The ecosystem properties selected were components of above-ground net primary productivity and decomposition of litter. KEY RESULTS: The wide variety of land-use systems that characterize marginal landscapes across Europe was reflected by the different disturbance indices, and were also reflected in soil and/or nutrient availability gradients. The trait toolkit allowed us to describe adequately the functional response of vegetation to land-use changes, but we suggest that some traits (vegetative plant height, stem dry matter content) should be omitted in studies involving mainly herbaceous species. Using the example of the relationship between leaf dry matter content and above-ground dead material, we demonstrate how the data collected may be used to analyse direct effects of climate and land use on ecosystem properties vs. indirect effects via changes in plant traits. CONCLUSIONS: This work shows the applicability of a set of protocols that can be widely applied to assess the impacts of global change drivers on species, communities and ecosystems.
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| [30] |
Biodiversity and ecosystem function: The debate deepens [J].https://doi.org/10.1126/science.277.5330.1260 URL [本文引用: 1] 摘要
One of the tenets of the conservation movement has been that areas containing many species--those of high biodiversity--are particularly worth saving, since ecosystems of high diversity show improved ecosystem function. As Grime explains in his Perspective, this tenet is being replaced by another view, which is bolstered by three reports in this week's issue (pages 1296, 1300, and 1302). These studies all show that it is actually the specific features of the species in an ecosystem that determine its function--not their number.
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| [31] |
Benefits of plant diversity to ecosystems: Immediate, filter and founder effects [J].https://doi.org/10.1046/j.1365-2745.1998.00306.x URL [本文引用: 1] 摘要
Abstract 1 It is useful to distinguish between the immediate effects of species richness on ecosystems and those which become apparent on a longer time scale, described here as filter and founder effects. 2 Relationships between plant diversity and ecosystem properties can be explored by classifying component species into three categories dominants, subordinates and transients. Dominants recur in particular vegetation types, are relatively large, exhibit coarse-grained foraging for resources and, as individual species, make a substantial contribution to the plant biomass. Subordinates also show high fidelity of association with particular vegetation types but they are smaller in stature, forage on a more restricted scale and tend to occupy microhabitats delimited by the architecture and phenology of their associated dominants. Transients comprise a heterogeneous assortment of species of low abundance and persistence; a high proportion are juveniles of species that occur as dominants or subordinates in neighbouring ecosystems. 3 A ass ratio theory proposes that immediate controls are in proportion to inputs to primary production, are determined to an overwhelming extent by the traits and functional diversity of the dominant plants and are relatively insensitive to the richness of subordinates and transients. Recent experiments support the mass ratio hypothesis and the conclusion of Huston (1997) that claims of immediate benefits of high species richness to ecosystem functions arise from misinterpretation of data. 4 Attribution of immediate control to dominants does not exclude subordinates and transients from involvement in the determination of ecosystem function and sustainability. Both are suspected to play a crucial, if intermittent, role by influencing the recruitment of dominants. Some subordinates may act as a filter influencing regeneration by dominants following major perturbations. 5 Transients originate from the seed rain and seed banks and provide an index of the pool of potential dominants and subordinates at specific sites. Where the landscape carousel operates against a background of declining diversity in the reservoir of colonizing transients, we may predict that a progressive loss of ecosystem functions will arise from the decline in the precision with which dominants can engage in the re-assembly and relocation of ecosystems.
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| [32] |
Morphological, physiological and anatomical traits of plant functional types in temperate grasslands along a large-scale aridity gradient in northeastern China [J].https://doi.org/10.1038/srep40900 URL PMID: 5247725 [本文引用: 1] 摘要
At the species level, plants can respond to climate changes by changing their leaf traits; however, there is scant information regarding the responses of morphological, physiological and anatomical traits of plant functional types (PFTs) to aridity. Herein, the leaf traits of five PFTs representing 17 plant species in temperate grasslands were examined along a large-scale aridity gradient in northeastern China. The results show that leaf thickness in shrubs, perennial grasses and forbs increased with heightened aridity. Trees increased soluble sugar content, but shrubs, perennials and annual grasses enhanced proline accumulation due to increasing aridity. Moreover, vessel diameter and stomatal index in shrubs and perennial grasses decreased with increasing aridity, but stomatal density and vascular diameter of five PFTs were not correlated with water availability. In conclusion, divergences in adaptive strategies to aridity among these PFTs in temperate grasslands were likely caused by differences in their utilization of water resources, which have different temporal and spatial distribution patterns. Leaf traits of shrubs and perennial grasses had the largest responses to variability of aridity through regulation of morphological, physiological and anatomical traits, which was followed by perennial forbs. Trees and annual grasses endured aridity only by adjusting leaf physiological processes.
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| [33] |
Leaf nitrogen and phosphorus stoichiometry across 753 terrestrial plant species in China [J].https://doi.org/10.1111/j.1469-8137.2005.01530.x URL PMID: 16219077 [本文引用: 1] 摘要
Abstract Leaf nitrogen and phosphorus stoichiometry of Chinese terrestrial plants was studied based on a national data set including 753 species across the country. Geometric means were calculated for functional groups based on life form, phylogeny and photosynthetic pathway, as well as for all 753 species. The relationships between leaf N and P stoichiometric traits and latitude (and temperature) were analysed. The geometric means of leaf N, P, and N : P ratio for the 753 species were 18.6 and 1.21 mg g(-1) and 14.4, respectively. With increasing latitude (decreasing mean annual temperature, MAT), leaf N and P increased, but the N : P ratio did not show significant changes. Although patterns of leaf N, P and N : P ratios across the functional groups were generally consistent with those reported previously, the overall N : P ratio of China's flora was considerably higher than the global averages, probably caused by a greater shortage of soil P in China than elsewhere. The relationships between leaf N, P and N : P ratio and latitude (and MAT) also suggested the existence of broad biogeographical patterns of these leaf traits in Chinese flora.
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| [34] |
Leaf nitrogen: Phosphorus stoichiometry across Chinese grassland biomes [J].https://doi.org/10.1007/s00442-007-0912-y URL PMID: 18278518 [本文引用: 1] 摘要
Leaf N and P stoichiometry covaries with many aspects of plant biology, yet the drivers of this trait at biogeographic scales remain uncertain. Recently we reported the patterns of leaf C and N based on systematic census of 213 species over 199 research sites in the grassland biomes of China. With the expanded analysis of leaf P, here we report patterns of leaf P and N:P ratios, and analyze the relative contribution of climatic variables and phylogeny in structuring patterns of leaf N:P stoichiometry. Average values of leaf P and N:P ratio were 1.9 mg g 1 and 15.3 (mass ratio), respectively, consistent with the previous observation of a higher N:P ratio in China flora than the global averages (ca. 13.8), resulting from a lower leaf P. Climatic variables had very little direct correlation with leaf P and N:P ratios, with growing season precipitation and temperature together explaining less than 2% of the variation, while inter-site differences and within-site phylogenetic variation explained 55 and 26% of the total variation in leaf P and N:P ratios. Across all sites and species, leaf N and P were highly positively correlated at all levels. However, the within-site, within-species covariations of leaf N and P were weaker than those across sites and across species. Leaf N and P relationships are driven by both variation between sites at the landscape scale (explaining 58% of the variance) and within sites at the local scale (explaining 24%), while the climatic factors exerted limited influence (explaining less than 3%). In addition, leaf N:P ratios in two dominant genera Kobresia and Stipa had different responses to precipitation. This study suggests that geographic variation and between-species variation, rather than climatic variation, are the major determinants of grassland foliar stoichiometry at the biome level.
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| [35] |
A test of the generality of leaf trait relationships on the Tibetan Plateau [J].https://doi.org/10.1111/j.1469-8137.2006.01704.x URL PMID: 16684242 [本文引用: 2] 摘要
Summary Top of page Summary Introduction Materials and Methods Results Discussion Acknowledgements References Supporting Information 6168 Leaf mass per area (LMA), nitrogen concentration (on mass and area bases, N mass and N area , respectively), photosynthetic capacity ( A mass and A area ) and photosynthetic nitrogen use efficiency (PNUE) are key foliar traits, but few data are available from cold, high-altitude environments. 6168 Here, we systematically measured these leaf traits in 74 species at 49 research sites on the Tibetan Plateau to examine how these traits, measured near the extremes of plant tolerance, compare with global patterns. 6168 Overall, Tibetan species had higher leaf nitrogen concentrations and photosynthetic capacities compared with a global dataset, but they had a slightly lower A mass at a given N mass . These leaf trait relationships were consistent with those reported from the global dataset, with slopes of the standardized major axes A mass –LMA, N mass –LMA and A mass – N mass identical to those from the global dataset. Climate only weakly modulated leaf traits. 6168 Our data indicate that covarying sets of leaf traits are consistent across environments and biogeographic regions. Our results demonstrate functional convergence of leaf trait relationships in an extreme environment.
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| [36] |
Variation in leaf anatomical traits from tropical to cold-temperate forests and linkage to ecosystem functions [J].https://doi.org/10.1111/1365-2435.12934 URL [本文引用: 1] 摘要
react-text: 532 Leaf caloric value (LCV) is a useful index to represent the conversion efficiency of leaves for solar energy. We investigated the spatial pattern of LCV and explored the factors (phylogeny, climate, and soil) that influence them at a large scale by determining LCV standardized by leaf area in 920 plant species from nine forest communities along the 3700 km North-South Transect of Eastern... /react-text react-text: 533 /react-text [Show full abstract]
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The ecology and management of grazing systems [M]. |
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Allocating C-S-R plant functional types: A soft approach to a hard problem [J].https://doi.org/10.2307/3546494 URL [本文引用: 1] 摘要
A long-term research programme, conducted mainly in northern England, has involved field surveys (1965-77), laboratory screening (1974-96), monitoring of permanent plots (1958 to date) and manipulative experiments (1987 to date). The so-called C-S-R classification of plant functional types developed from all this activity. Patterns of covariation among the traits used in the classification have recently been validated in this journal. The C-S-R classification appears to be applicable to vegetation in general. It thus has considerable potential for interpreting and predicting vegetation and ecosystem properties on a world-wide scale. However, to realize this potential we need to develop simplified procedures to extrapolate the C-S-R system to the many species which have not been the subject of previous ecological investigation. Here we describe a rapid method for attribution of C-S-R type and we test its accuracy in Britain by comparing it with an independent classification based upon more laborious procedures. The new method allocates a functional type to an unknown herbaceous subject using few, simple predictor variables. We have developed spreadsheets to perform all of the necessary calculations. These may be downloaded from the UCPE website at http://www.shef.ac.uk/uni/academic/N-Q/nuocpe, or obtained by direct application to the E-mail address ucpe@sheffield.ac.uk
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| [39] |
The effects of plant composition and diversity on ecosystem processes [J].https://doi.org/10.1126/science.277.5330.1302 URL [本文引用: 2] |
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A global fine-root ecology database to address below-ground challenges in plant ecology [J].https://doi.org/10.1111/nph.14486 URL [本文引用: 1] |
| [41] |
TRY-a global database of plant traits [J].https://doi.org/10.1111/gcb.v17.9 URL [本文引用: 4] |
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The LEDA Traitbase: A database of life-history traits of the Northwest European flora [J].https://doi.org/10.1111/jec.2008.96.issue-6 URL [本文引用: 1] |
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Life-history traits of the Northwest European flora: The LEDA database [J].https://doi.org/10.1111/j.1654-1103.2003.tb02188.x URL [本文引用: 1] 摘要
Abstract Abstract. An international group of scientists is building a ‘trait base’, an open internet database of life-history traits of the Northwest European flora (LEDA) that can be used as a tool in planning, in nature conservation and restoration, and in other applied research. The species-trait matrix will comprise referenced information under control of an editorial board, for species of the Northwest European flora, combining existing information and additional measurements. The focus will be on 26 plant traits that describe three key features of plant dynamics: persistence, regeneration, and dispersability. Currently 35% of the species-trait matrix has been filled; however, as the LEDA trait base consortium aims to deliver a database as complete as possible, all input from the scientific community is welcome.
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| [44] |
Predicting changes in community composition and ecosystem functioning from plant traits: Revisiting the Holy Grail [J].https://doi.org/10.1046/j.1365-2435.2002.00664.x URL [本文引用: 1] 摘要
Summary 1 The concept of plant functional type proposes that species can be grouped according to common responses to the environment and/or common effects on ecosystem processes. However, the knowledge of relationships between traits associated with the response of plants to environmental factors such as resources and disturbances (response traits), and traits that determine effects of plants on ecosystem functions (effect traits), such as biogeochemical cycling or propensity to disturbance, remains rudimentary. 2 We present a framework using concepts and results from community ecology, ecosystem ecology and evolutionary biology to provide this linkage. Ecosystem functioning is the end result of the operation of multiple environmental filters in a hierarchy of scales which, by selecting individuals with appropriate responses, result in assemblages with varying trait composition. Functional linkages and trade-offs among traits, each of which relates to one or several processes, determine whether or not filtering by different factors gives a match, and whether ecosystem effects can be easily deduced from the knowledge of the filters. 3 To illustrate this framework we analyse a set of key environmental factors and ecosystem processes. While traits associated with response to nutrient gradients strongly overlapped with those determining net primary production, little direct overlap was found between response to fire and flammability. 4 We hypothesize that these patterns reflect general trends. Responses to resource availability would be determined by traits that are also involved in biogeochemical cycling, because both these responses and effects are driven by the trade-off between acquisition and conservation. On the other hand, regeneration and demographic traits associated with response to disturbance, which are known to have little connection with adult traits involved in plant ecophysiology, would be of little relevance to ecosystem processes. 5 This framework is likely to be broadly applicable, although caution must be exercised to use trait linkages and trade-offs appropriate to the scale, environmental conditions and evolutionary context. It may direct the selection of plant functional types for vegetation models at a range of scales, and help with the design of experimental studies of relationships between plant diversity and ecosystem properties.
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| [45] |
Assessing functional diversity in the field-methodology matters! [J].https://doi.org/10.1111/j.1365-2435.2007.01339.x URL [本文引用: 1] 摘要
Summary 1 Interpreting the functional diversity of vegetation is important in unravelling the relationship between environmental change, community composition and ecosystem processes. Functional diversity is the range and distribution of functional trait values in a community. It can be described, among other indicators, by community-level weighted means of trait values (CWM) and functional divergence. Standard methods exist for trait measurements but not for assessments of CWM and functional divergence in the field. No research has addressed the effects of different methods of estimating relative abundances, nor the need to estimate traits at individual, population or species level, or whether methods could be used that bypass taxonomy all together. 2 This study reviews and evaluates plot-level assessment methods of functional diversity in herbaceous vegetation. We asked: (i) Should the objective of the study influence the method for estimating relative abundance? (ii) What are the strengths and limitations of intensive vs. apid approaches, and when should either be applied? (iii) Are taxon-free methods robust in comparison to taxon-explicit methods of trait measurement? Under what circumstances might they be applied? 3 Our review of published studies that have measured functional diversity in the field showed that the choice of metric has not generally taken into account the link between the metric and the functions of interest, and that vegetation cover has been most widely used, regardless of study purpose. 4 We compared quantitatively in subalpine grasslands three methods for quantification of species abundances plus one taxon-free method. We found that: (i) data base trait values were robust across years for a diverse set of dominant species; (ii) CWM have little sensitivity to method for estimating relative abundances; this sensitivity also depends on traits, for example, seed mass results were less stable than leaf traits and heights; (iii) robust estimates of CWM were obtained from visual estimates of species ranks and biomass using a dry-weight ranking method (BOTANAL), whereas functional divergence was more sensitive to method; and (iv) the taxon-free method should be treated with more caution and performed particularly poorly for estimates of functional divergence. 5 We conclude that methodology can affect estimates of functional diversity. Although care should be taken in the choice of method and interpretation of results, rapid methods often offer promising avenues for sampling larger areas and/or repeated measures.
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| [46] |
Ecology: A trail map for trait-based studies [J].https://doi.org/10.1038/nature16862 URL PMID: 26700809 [本文引用: 2] 摘要
Global assessments of variation in plant functional traits and the way that these traits influence competitive interactions provide a launching pad for future ecological studies. See Article p.167 & Letter p.204
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| [47] |
Biodiversity and ecosystem functioning: Current knowledge and future challenges [J].https://doi.org/10.1126/science.1064088 URL PMID: 11679658 [本文引用: 1] 摘要
Abstract The ecological consequences of biodiversity loss have aroused considerable interest and controversy during the past decade. Major advances have been made in describing the relationship between species diversity and ecosystem processes, in identifying functionally important species, and in revealing underlying mechanisms. There is, however, uncertainty as to how results obtained in recent experiments scale up to landscape and regional levels and generalize across ecosystem types and processes. Larger numbers of species are probably needed to reduce temporal variability in ecosystem processes in changing environments. A major future challenge is to determine how biodiversity dynamics, ecosystem processes, and abiotic factors interact.
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| [48] |
Plant traits and functional types in response to reduced disturbance in a semi-natural grassland [J].https://doi.org/10.1111/j.1654-1103.2005.tb02350.x URL [本文引用: 1] 摘要
Question: How do functional types respond to contrasting levels of herbage use in temperate and fertile grasslands?
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| [49] |
An index of functional diversity [J].https://doi.org/10.1111/j.1654-1103.2003.tb02184.x URL [本文引用: 1] 摘要
Functional diversity has been seen as the key to predicting the stability, invasibility, resource capture, nutrient cycling and productivity of communities. However, it has been unclear how to estimate it. Ten criteria for an index of functional diversity are developed. These include that it should reflect the range of characters present and the abundance of the species with those characters in the community, and be unaffected by the measurement units used or by the number of species. An index that meets all ten criteria, FDvar, is investigated. It is based on the variance in characters, weighted by the abundance of the species with those characters. Tested with artificial and randomly generated data, it showed reasonable use of the 0 - 1 range (mean 0.60, range 0.0009 - 0.975) and intuitive behaviour. Tested with field data from eight sites in New Zealand, it gave a good spread of values (mean 0.65, range across sites 0.34 - 0.84), showed good ability to distinguish between the communities and its performance was ecologically intuitive. Illustrative correlations are made with mean annual temperature and soil fertility, determined by a bioassay. FDvar is recommended for general use.
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| [50] |
Functional richness, functional evenness and functional divergence: The primary components of functional diversity [J].https://doi.org/10.1111/j.0030-1299.2005.13886.x URL [本文引用: 1] 摘要
Functional diversity is hypothesised as being beneficial for ecosystem functions, such as productivity and resistance to invasion. However, a precise definition of functional diversity, and hence a framework for its quantification, have proved elusive. We present a definition based on the analogy of the components of species diversity - richness, evenness and divergence. These concepts are applied to functional characters to give three components of functional diversity - functional richness, functional evenness and functional divergence. We demonstrate how each of these components may be calculated. It is hoped that our definition of functional diversity and its components will aid in elucidation of the mechanisms behind diversity/ecosystem-function relationships.
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| [51] |
Functional identity is more important than diversity in influencing ecosystem processes in a temperate native grassland [J].https://doi.org/10.1111/j.1365-2745.2008.01395.x URL [本文引用: 1] 摘要
Summary 1 Experimental studies have provided significant knowledge of how biodiversity can influence ecosystem processes. However, there is a growing need to relate these findings to natural communities. 2 Here we identify two major hypotheses for how communities may influence ecosystem processes: the ‘diversity hypothesis’ (the diversity of organisms in a community influences ecosystem processes through mechanisms such as complementary resource use), and the ‘mass ratio hypothesis’ (ecosystem processes are determined overwhelmingly by the functional traits of the dominant species). We then test which of these two hypotheses best explain variation in ecosystem properties and processes (biomass pools and fluxes, water use, light interception) in a temperate native grassland. We do this by applying various measures of diversity, functional diversity, and functional identity, whose significant relations with ecosystem processes would support either of the competing hypotheses. 3 Mean trait values best explained variation in five of the eight ecosystem processes examined, supporting Grime's mass ratio hypothesis, which proposes that the functional identities of the dominant species largely determine ecosystem processes. 4 Multi-trait functional diversity indices also explained large amounts of variation in ecosystem processes, while only weak relationships were observed between species richness and ecosystem processes. 5 To explore the mechanistic interactions between variables, we developed structural equation models (SEMs), which indicated that many of the community diversity and trait properties significantly influenced ecosystem processes, even after accounting for co-varying biotic/abiotic factors. 6 Synthesis . Our study is one of the first explicit comparisons of the ‘diversity’ and ‘mass ratio’ hypotheses, and our results most strongly support the mass ratio hypothesis, that is, the traits of the dominant species most influenced the ecosystem properties and processes examined. Our results suggest that the management of communities for the maintenance of ecosystem processes should focus on species dominance hierarchies.
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| [52] |
Functional diversity measures: An overview of their redundancy and their ability to discriminate community assembly rules [J].https://doi.org/10.1111/j.1365-2435.2010.01695.x URL [本文引用: 3] 摘要
1. Indices quantifying the functional aspect of biodiversity are essential in understanding relationships between biodiversity, ecosystem functioning and environmental constraints. Many indices of functional diversity have been published but we lack consensus about what indices quantify, how redundant they are and which ones are recommended.2. This study aims to build a typology of functional diversity indices from artificial data sets encompassing various community structures (different assembly rules, various species richness levels) and to identify a set of independent indices able to discriminate community assembly rules.3. Our results confirm that indices can be divided into three main categories, each of these corresponding to one aspect of functional diversity: functional richness, functional evenness and functional divergence. Most published indices are highly correlated and quantify functional richness while quadratic entropy (Q) represents a mix between functional richness and functional divergence. Conversely, two indices (FEve and FDiv respectively quantifying functional evenness and functional divergence) are rather independent to all the others. The power analysis revealed that some indices efficiently detect assembly rules while others performed poorly.4. To accurately assess functional diversity and establish its relationships with ecosystem functioning and environmental constraints, we recommend investigating each functional component separately with the appropriate index. Guidelines are provided to help choosing appropriate indices given the issue being investigated.5. This study demonstrates that functional diversity indices have the potential to reveal the processes that structure biological communities. Combined with complementary methods (phylogenetic and taxonomic diversity), the multifaceted framework of functional diversity will help improve our understanding of how biodiversity interacts with ecosystem processes and environmental constraints.
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| [53] |
Functional regularity: A neglected aspect of functional diversity [J].https://doi.org/10.1007/s00442-004-1744-7 URL PMID: 15655690 [本文引用: 1] 摘要
Functional diversity has been identified as a key to understanding ecosystem and community functioning. However, due to the lack of a sound definition its nature and measurement are still poorly understood. In the same way that species diversity can be split into species richness and species evenness, so functional diversity can be split into functional richness (i.e. the amount of functional trait/character/attribute space filled) and functional evenness (i.e. the evenness of abundance distribution in functional trait space). We propose a functional regularity index (FRO) as a measure of functional evenness for situations where species are represented only by a single functional trait value (e.g. mean, median or mode), and species abundances are known. This new index is based on the Bulla O index of species evenness. When dealing with functional types or categorical functional traits, the Bulla O or any other accepted species evenness index may be used directly to measure functional evenness. The advantage of FRO is that it supplies a measure of functional evenness for continuous trait data. The FRO index presented in this paper fulfils all the a priori criteria required. We demonstrate with two example datasets that a range of FRO values may be obtained for both plant and animal communities. Moreover, FRO was strongly related to ecosystem function as seen in photosynthetic biomass in plant communities, and was able to differentiate sampling stations in a lagoon based on the functional traits of fish. Thus, the FRO index is potentially a highly useful tool for measuring functional diversity in a variety of ecological situations.
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| [54] |
Which plant traits respond to aridity? A critical step to assess functional diversity in Mediterranean drylands [J].https://doi.org/10.1016/j.agrformet.2017.03.007 URL [本文引用: 1] 摘要
Our results fill an important knowledge gap by quantifying how the functional structure and dispersion of 13 plant traits change with aridity at the whole-community level, providing an important basis for the selection of key functional traits to be used in trait-based studies in drylands.
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| [55] |
Spatial resilience of coral reefs [J].https://doi.org/10.1007/s10021-001-0019-y URL [本文引用: 1] |
| [56] |
New handbook for standardised measurement of plant functional traits worldwide [J].https://doi.org/10.1071/BT12225 URL [本文引用: 2] 摘要
Plant functional traits are the features (morphological, physiological, phenological) that represent ecological strategies and determine how plants respond to environmental factors, affect other trophic levels and influence ecosystem properties. Variation in plant functional traits, and trait syndromes, has proven useful for tackling many important ecological questions at a range of scales, giving rise to a demand for standardised ways to measure ecologically meaningful plant traits. This line of research has been among the most fruitful avenues for understanding ecological and evolutionary patterns and processes. It also has the potential both to build a predictive set of local, regional and global relationships between plants and environment and to quantify a wide range of natural and human-driven processes, including changes in biodiversity, the impacts of species invasions, alterations in biogeochemical processes and vegetation-atmosphere interactions. The importance of these topics dictates the urgent need for more and better data, and increases the value of standardised protocols for quantifying trait variation of different species, in particular for traits with power to predict plant-and ecosystem-level processes, and for traits that can be measured relatively easily. Updated and expanded from the widely used previous version, this handbook retains the focus on clearly presented, widely applicable, step-by-step recipes, with a minimum of text on theory, and not only includes updated methods for the traits previously covered, but also introduces many new protocols for further traits. This new handbook has a better balance between whole-plant traits, leaf traits, root and stem traits and regenerative traits, and puts particular emphasis on traits important for predicting species' effects on key ecosystem properties. We hope this new handbook becomes a standard companion in local and global efforts to learn about the responses and impacts of different plant species with respect to environmental changes in the present, past and future.
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| [57] |
How to design trait-based analyses of community assembly mechanisms: Insights and guidelines from a literature review [J].https://doi.org/10.1016/j.ppees.2017.01.004 URL [本文引用: 1] 摘要
From this extensive review, we highlight major conceptual and methodological issues that need to be addressed in trait-based null model approaches. We synthesize the methodological choices relevant to study several assembly mechanisms while minimizing methodological biases. We then derive practical guidelines and emphasize the importance of spatial structure in sampling strategy and null model design, because of the scale-dependent signatures of ecological processes.
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| [58] |
Summer freezing resistance: A critical filter for plant community assemblies in Mediterranean high mountains [J].https://doi.org/10.3389/fpls.2016.00194 URL PMID: 4761790 [本文引用: 1] 摘要
Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain) by measuring their ice nucleation temperature, freezing point (FP), and low-temperature damage (LT50), as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance). The community response to freezing was estimated for each plot as community weighted means (CWMs) and functional diversity (FD), and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content (LDMC), and seed mass). There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50responded negatively to altitude, whereas the FD of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50varied among growth forms, and only leaf dry matter content was negatively correlated with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower FD of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to be a general prerequisite for plants found in xeric mountains.
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| [59] |
Functional diversity (FD), species richness and community composition [J].https://doi.org/10.1046/j.1461-0248.2002.00339.x URL [本文引用: 1] |
| [60] |
Functional diversity: Back to basics and looking forward [J].https://doi.org/10.1111/ele.2006.9.issue-6 URL [本文引用: 2] |
| [61] |
Invasions: The perspective of diverse plant communities [J].https://doi.org/10.1046/j.1442-9993.2000.01033.x URL [本文引用: 1] 摘要
Exotic plant invasions represent a threat to natural and managed ecosystems. Understanding of the mechanisms that determine why a given species may invade a given ecosystem, or why some biomes and regions seem more prone to invasions, is limited. One potential reason for this lack of progress may lie in how few studies have addressed invasion mechanisms from the point of view of the invaded community. On the other hand, the renewed debate about the relationship between ecological diversity and ecosystem stability offers the opportunity to revisit existing theory and empirical evidence, and to attempt to investigate which characteristics of plant communities, including their diversity, contribute to their invasibility. Empirical studies have shown both positive and negative relationships between species diversity of resident plant communities and their invasibility by external species. Rather than attempting to build a larger collection of case studies, research now needs to address the mechanisms underlying these relationships. Previous knowledge about the mechanisms favouring invasion needs to be coupled with community theory to form the basis of these new investigations. Modern community theory offers hypotheses and techniques to analyse the invasibility of communities depending on their diversity and other factors, such as species life histories and environmental variability. The body of knowledge accumulated in invasion ecology suggests that the role of disturbances, in interaction with fertility, and the importance of interactions with other trophic levels, are specific factors for consideration. In addition, it is essential for future studies to explicitly tease apart the effects of species richness per se from the effects of other components of ecological diversity, such as functional diversity (the number of functional groups) and trophic diversity (the number of interactions among trophic levels).
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| [62] |
Elevation, moisture and shade drive the functional and phylogenetic meadow communities' assembly in the northeastern Tibetan Plateau [J].https://doi.org/10.1556/168.2015.16.1.8 URL [本文引用: 3] 摘要
Despite a long history of alpine meadows studies, uncertainty remains about the importance of environmental factors in structuring their assembly. We examined the functional and phylogenetic structure of 170 alpine Tibetan meadow communities in relation to elevation, soil moisture and shade. Functional community structure was estimated with both communityweighted mean (CWM) trait values for specific leaf area (SLA), plant height and seed mass and functional diversity (Rao quadratic index) for their traits individually and in combination (multivariate functional diversity). We found that shade induced by woody plants significantly increased the phylogenetic diversity and functional diversity of SLA of co-occurring species, suggesting that woody plants behave as cosystem engineers creating a different environment that allows the existence of shade tolerant species and thereby facilitates the coexistence of plant species with different light resource acquisition strategies. We also found evidence for a clear decrease in phylogenetic diversity, CWM and functional diversity related to plant height in the two extreme, both the dry and wet, soil moisture conditions. This indicates that both drought and excess moisture may act as environmental filters selecting species with close phylogenetic relationships and similar height. Moreover, we detected significant decreases in both CWM and functional diversity for seed mass along elevational gradients, suggesting that low net primary productivity (NPP) limits seed size. Finally, because of different individual trait responses to environmental factors, the multivariate functional diversity did not change across environmental gradients. This lack of multivariate response supports the hypothesis that multiple processes, such as environmental filtering, competition and facilitation, may operate simultaneously and exert opposing effects on community assembly along different niche (e.g., water use, light acquisition) axes, resulting in no overall functional community structure change. This contrast between individual and multivariate trait patterns highlights the importance of examining individual traits linked with different ecological processes to better understand the mechanisms of community assembly.
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| [63] |
Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots [J].https://doi.org/10.1073/pnas.1216053111 URL [本文引用: 1] 摘要
Whether the fraction of total forest biomass distributed in roots, stems, or leaves varies systematically across geographic gradients remains unknown despite its importance for understanding forest ecology and modeling global carbon cycles. It has been hypothesized that plants should maintain proportionally more biomass in the organ that acquires the most limiting resource. Accordingly, we hypothesize greater biomass distribution in roots and less in stems and foliage in increasingly arid climates and in colder environments at high latitudes. Such a strategy would increase uptake of soil water in dry conditions and of soil nutrients in cold soils, where they are at low supply and are less mobile. We use a large global biomass dataset (>6,200 forests from 61 countries, across a 40 C gradient in mean annual temperature) to address these questions. Climate metrics involving temperature were better predictors of biomass partitioning than those involving moisture availability, because, surprisingly, fractional distribution of biomass to roots or foliage was unrelated to aridity. In contrast, in increasingly cold climates, the proportion of total forest biomass in roots was greater and in foliage was smaller for both angiosperm and gymnosperm forests. These findings support hypotheses about adaptive strategies of forest trees to temperature and provide biogeographically explicit relationships to improve ecosystem and earth system models. They also will allow, for the first time to our knowledge, representations of root carbon pools that consider biogeographic differences, which are useful for quantifying whole-ecosystem carbon stocks and cycles and for assessing the impact of climate change on forest carbon dynamics.
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| [64] |
Global patterns of plant leaf N and P in relation to temperature and latitude [J].https://doi.org/10.1073/pnas.0403588101 URL PMID: 15213326 [本文引用: 2] 摘要
A global data set including 5,087 observations of leaf nitrogen (N) and phosphorus (P) for 1,280 plant species at 452 sites and of associated mean climate indices demonstrates broad biogeographic patterns. In general, leaf N and P decline and the N/P ratio increases toward the equator as average temperature and growing season length increase. These patterns are similar for five dominant plant groups, coniferous trees and four angiosperm groups (grasses, herbs, shrubs, and trees). These results support the hypotheses that (i) leaf N and P increase from the tropics to the cooler and drier midlatitudes because of temperature-related plant physiological stoichiometry and biogeographical gradients in soil substrate age and then plateau or decrease at high latitudes because of cold temperature effects on biogeochemistry and (ii) the N/P ratio increases with mean temperature and toward the equator, because P is a major limiting nutrient in older tropical soils and N is the major limiting nutrient in younger temperate and high-latitude soils.
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| [65] |
Biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections [J].https://doi.org/10.1073/pnas.1216054110 URL [本文引用: 2] 摘要
Leaf life span is an important plant trait associated with interspecific variation in leaf, organismal, and ecosystem processes. We hypothesized that intraspecific variation in gymnosperm needle traits with latitude reflects both selection and acclimation for traits adaptive to the associated temperature and moisture gradient. This hypothesis was supported, because across 127 sites along a 2,160-km gradient in North America individuals of Picea glauca, Picea mariana, Pinus banksiana, and Abies balsamea had longer needle life span and lower tissue nitrogen concentration with decreasing mean annual temperature. Similar patterns were noted for Pinus sylvestris across a north-south gradient in Europe. These differences highlight needle longevity as an adaptive feature important to ecological success of boreal conifers across broad climatic ranges. Additionally, differences in leaf life span directly affect annual foliage turnover rate, which along with needle physiology partially regulates carbon cycling through effects on gross primary production and net canopy carbon export. However, most, if not all, global land surface models parameterize needle longevity of boreal evergreen forests as if it were a constant. We incorporated temperature-dependent needle longevity and %nitrogen, and biomass allocation, into a land surface model, Community Atmosphere Biosphere Land Exchange, to assess their impacts on carbon cycling processes. Incorporating realistic parameterization of these variables improved predictions of canopy leaf area index and gross primary production compared with observations from flux sites. Finally, increasingly low foliage turnover and biomass fraction toward the cold far north indicate that a surprisingly small fraction of new biomass is allocated to foliage under such conditions.
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| [66] |
Leaf life-span in relation to leaf, plant, and stand characteristics among diverse ecosystems [J].https://doi.org/10.2307/2937116 URL [本文引用: 3] |
| [67] |
From tropics to tundra: Global convergence in plant functioning [J].https://doi.org/10.1073/pnas.94.25.13730 URL PMID: 9391094 [本文引用: 2] 摘要
Despite striking differences in climate, soils, and evolutionary history among diverse biomes ranging from tropical and temperate forests to alpine tundra and desert, we found similar interspecific relationships among leaf structure and function and plant growth in all biomes. Our results thus demonstrate convergent evolution and global generality in plant functioning, despite the enormous diversity of plant species and biomes. For 280 plant species from two global data sets, we found that potential carbon gain (photosynthesis) and carbon loss (respiration) increase in similar proportion with decreasing leaf life-span, increasing leaf nitrogen concentration, and increasing leaf surface area-to-mass ratio. Productivity of individual plants and of leaves in vegetation canopies also changes in constant proportion to leaf life-span and surface area-to-mass ratio. These global plant functional relationships have significant implications for global scale modeling of vegetation-atmosphere CO2 exchange.
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| [68] |
Predicting leaf physiology from simple plant and climate attributes: A global GLOPNET analysis [J].https://doi.org/10.1890/06-1803.1 URL [本文引用: 1] |
| [69] |
CWM and Rao's quadratic diversity: A unified framework for functional ecology [J].https://doi.org/10.1007/s00442-011-1965-5 URL PMID: 21424717 [本文引用: 1] 摘要
Abstract Assessing the effects of environmental constraints on community structure often relies on methods that consider changes in species functional traits in response to environmental processes. Various indices have been proposed to measure relevant aspects of community trait composition from different viewpoints and perspectives. Among these, the 'community-weighted mean trait value' (CWM) and the Rao coefficient have been widely used in ecological research for summarizing different facets of functional composition and diversity. Analyzing changes in functional diversity of bee communities along a post-fire successional gradient in southern Switzerland we show that these two measures may be used to describe two complementary aspects of community structure, such as the mean and the dispersion of functional traits within a given species assemblage. While CWM can be adequately used to summarize shifts in mean trait values within communities due to environmental selection for certain functional traits, the Rao coefficient can be effectively applied to analyze patterns of trait convergence or divergence compared to a random expectation.
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| [70] |
Plant traits link hypothesis about resource-use and response to herbivory [J].https://doi.org/10.1016/j.baae.2009.01.004 URL [本文引用: 1] 摘要
Die Beweidung durch gro08e Herbivore stellt im Zusammenspiel mit der Produktivit01t der Umwelt einen Schlüsselfaktor für die Zusammensetzung der Vegetation dar und hat damit gro08e Auswirkungen auf das 00kosystem und dementsprechend für die Landpflege. Wir untersuchten die Vorhersagen der Ressourcenverfügbarkeits-Ressourcenerwerbs-Theorie indem wir absch01tzten, in welchem Ausma08 die durchschnittlichen Pflanzeneigenschaften einer Gesellschaft, die erwiesenerma08en mit dem Pflanzenwachstum, der Konkurrenzf01higkeit und der Reaktion auf Beweidung zusammenh01ngen, mit den Ressourcengradienten innerhalb von lokalen geografischen Bereichen (200km 2 ) korreliert sind. Wir bewerteten zweitens die Anwendbarkeit der gleichen Auswahl von Pflanzeneigenschaften für die Absch01tzung von 02kologischen Effekten der Schafsbeweidung auf alpine 00kosysteme in Norwegen, indem wir einen Datensatz verwendeten, der aus 16 Probefl01chen in Zentralnorwegen bestand. Wir erfassten die Beweidungsintensit01t von freilaufenden Schafen mithilfe der GPS-Telemetrie, die Bodenfaktoren, die Zusammensetzung der Pflanzenarten und die Arteigenschaften, d. h. die spezifische Blattfl01che (SLA), die Blatttrockenmasse (LDMC), die Blattgr0208e und Pflanzenh02he. Die Bodenfruchtbarkeit und die Interaktion zwischen der Bodenfruchtbarkeit und der Beweidung, jedoch nicht die Beweidungsintensit01t an sich, waren mit den Pflanzenarten und der Zusammensetzung der Eigenschaften signifikant korreliert. Im Allgemeinen zeigte die durchschnittliche SLA einen geringeren Zusammenhang mit der Bodenfruchtbarkeit und der Beweidung als die anderen Eigenschaften. Die Blattfl01che und die Pflanzenh02he waren auf Fl01chen mit starker Beweidung und auf Fl01chen mit geringer Fruchtbarkeit, am geringsten, nahmen aber mit der Bodenfruchtbarkeit in gering und mittelstark beweideten Fl01chen zu und nahmen in fruchtbaren Fl01chen bei starker Beweidung ab. LDMC zeigte den gegenl01ufigen Trend. Die Beweidungsintensit01t war st01rker mit der Variabilit01t in der Pflanzenzusammensetzung und den durchschnittlichen Pflanzeneigenschaften verbunden, wenn die Produktivit01t der Umwelt hoch war. Unsere Ergebnisse weisen daher auf eine Konvergenz der Reaktionen auf Beweidung und N01hrstofflimitierung hin.
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| [71] |
Nutrient content in Quercus ilex canopies: Seasonal and spatial variation within a catchment [J].https://doi.org/10.1002/art.21718 URL [本文引用: 1] 摘要
Spatial and temporal changes in canopy nutrient content were studied in 1988 and 1989 in a Mediterranean Quercus ilex ssp. ilex L. forest in north-eastern Spain. Sampling was conducted in parallel at two sites which represent endpoints along a slope gradient within a small catchment (ridge top at 975 m and valley bottom at 700 m). Deeper soils resulted in significantly higher N and P concentrations, and N content on a leaf area basis at the valley bottom site. In contrast, K concentration in leaves was significantly higher at the ridge top site, where soil K concentration was also higher. At both sites, N and P content on a leaf area basis was highest at the top of the canopy, where leaf area is highest. N resorption efficiency decreased from top to bottom of the canopy. Results suggested a minor role of shaded leaves as nutrient storage sites. Lower P resorption efficiency was found at the ridge top site. Seasonal changes of P and N concentration on a leaf area basis suggest P replenishment, and to a lesser degree N, during periods of lower growth activity due to low temperatures, but coinciding with higher water availability (autumn-early spring period). Thus, N and P resorption from the remaining foliage in the canopy took place, and to a larger degree at the valley bottom site, coinciding with a slightly higher leaf area index and productivity at this site.
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| [72] |
Contrasting trait responses in plant communities to experimental and geographic variation in precipitation [J].https://doi.org/10.1111/j.1469-8137.2010.03382.x URL [本文引用: 2] |
| [73] |
Community-weighted means and functional dispersion of plant functional traits along environmental gradients on Mount Kilimanjaro [J].https://doi.org/10.1111/jvs.12542 URL [本文引用: 1] 摘要
Abstract How do community-weighted means of traits (CWM) and functional dispersion (FDis), a measure of trait variability, change in response to gradients of temperature, precipitation, soil nutrients, and disturbance? Is the decrease in trait similarity between plots continuous or discontinuous? Is species turnover between plots linked to trait turnover? Mount Kilimanjaro, Tanzania, Africa. Sixty plots were established in twelve major vegetation types on Mount Kilimanjaro, covering large gradients of temperature, precipitation, soil nutrients, and anthropogenic disturbance representing the dominant ecosystems in East Africa. Environmental data, plant abundances, and plant traits were recorded for each plot. Trait CWM and FDis were related to environmental factors with partial least squares regressions. Trait similarity between pairs of plots was assessed with a null-model approach. Both CWM and FDis of most traits responded strongly to environmental factors, particularly to precipitation and disturbance. FDis of traits associated with growth and reproduction mostly increased with temperature and precipitation, and decreased with disturbance. Pairwise plot comparisons revealed an inverse relationship of trait similarity with differences in temperature, precipitation, and anthropogenic disturbance, respectively. However, changes in similarity were often discontinuous rather than continuous. Several vegetation types differed strongly in species composition but not in traits. Trait dispersion indicating functional niches increased with productivity and temperature. Conversely, low-productivity conditions were characterized by trait convergence. Discontinuous changes in trait similarity between plots suggested tipping points at which trait expressions change strongly to adjust to environmental conditions. Large sections of the temperature gradient were characterized by species turnover with only minor changes in traits, indicating that the functional composition may be resilient against gradual environmental changes until a tipping point is reached. This article is protected by copyright. All rights reserved.
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| [74] |
Mapping functional diversity from remotely sensed morphological and physiological forest traits [J].https://doi.org/10.1038/s41467-017-01530-3 URL PMID: 5682291 [本文引用: 2] 摘要
Assessing functional diversity from space can help predict productivity and stability of forest ecosystems at global scale using biodiversity cosystem functioning relationships. We present a new spatially continuous method to map regional patterns of tree functional diversity using combined laser scanning and imaging spectroscopy. The method does not require prior taxonomic information and integrates variation in plant functional traits between and within plant species. We compare our method with leaf-level field measurements and species-level plot inventory data and find reasonable agreement. Morphological and physiological diversity show consistent change with topography and soil, with low functional richness at a mountain ridge under specific environmental conditions. Overall, functional richness follows a logarithmic increase with area, whereas divergence and evenness are scale invariant. By mapping diversity at scales of individual trees to whole communities we demonstrate the potential of assessing functional diversity from space, providing a pathway only limited by technological advances and not by methodology. As remote sensing technology improves, it is now possible to map fine-scale variation in plant functional traits. Schneideret al. remotely sense tree functional diversity, validate with field data, and reveal patterns of plant adaptation to the environment previously not retrievable from plot data
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| [75] |
Grassland responses to grazing: Effects of grazing intensity and management system in an Inner Mongolian steppe ecosystem [J].https://doi.org/10.1007/s11104-010-0366-6 URL [本文引用: 1] 摘要
The major aims of this study were, firstly, to analyse the grazing-induced steppe degradation process and, secondly, to identify an efficient and sustainable grazing management system for the widely degraded Inner Mongolian typical steppe ecosystem. From 2005–2008 a grazing experiment was conducted to compare two grazing management systems, the Mixed System (MS) and the Traditional System (TS), along a gradient of seven grazing intensities, i.e. ungrazed (GI0), very-light (GI1), light (GI2), light-moderate (GI3), moderate (GI4), heavy (GI5), and very-heavy (GI6). Each grazing intensity treatment was considered a production unit comprising two adjacent plots, one for hay-making (single-cut system) and one for grazing. Hay-making and grazing alternated annually in the MS, while in the TS the same plots were used either for hay-making or for grazing. Effects of management system, grazing intensity, and year on end-of-season standing biomass (ESSB), aboveground net primary production (ANPP), relative difference in ANPP between 2005 and 2008 (ANPP Diff ), relative growth rate (RGR), and sward characteristics (litter accumulation, soil coverage) were analysed. Litter accumulation of production units was affected by grazing intensity ( P 65<650.001) and decreased from GI0 to GI6 by 83%. Correspondingly, soil coverage decreased ( P 65<650.001) from GI0 to GI6 by 43%, indicating an increased vulnerability to soil erosion. We found varying compensatory growth responses to grazing intensity among years, probably because of temporal variability in precipitation. The ability of plants to partially compensate for grazing damage was enhanced in years of greater seasonal precipitation. The ANPP of production units was negatively affected by grazing intensity and decreased from GI0 to GI6 by 37, 30, and 55% in 2006 ( P 65<650.01), 2007 ( P 65<650.05), and 2008 ( P 65<650.001), respectively. The effect of management system × grazing intensity interaction on ANPP ( P 65<650.05) and ANPP Diff ( P 65<650.05) suggested greater grazing resilience of the MS as compared to the TS at GI3 to GI6.
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| [76] |
Differential effects of functional traits on aboveground biomass in semi-natural grasslands [J].https://doi.org/10.1111/j.1600-0706.2009.17711.x URL [本文引用: 1] 摘要
Despite increasing evidence on the importance of species functional characteristics for ecosystem processes, two major hypotheses suggest different mechanisms: the 'mass ratio hypothesis' assumes that functional traits of the dominant species determine ecosystem processes, while the 'complementarity hypothesis' predicts that resource niches may be used more completely when a community is functionally more diverse. Here, we present a method which uses two different groups of biotic predictor variables being (1) abundance-weighted mean (=aggregated) trait values and (2) functional trait diversity based on Rao's quadratic diversity (FDQ) to test the competing hypotheses on biodiversity-ecosystem functioning relationships after accounting for co-varying abiotic factors. We applied this method to data recorded on biodiversity-biomass relationships and environmental variables in 35 semi-natural temperate grasslands and used a literature-based matrix of fourteen plant functional traits to assess the explanatory power of models including different sets of predictor variables. Aboveground community biomass did not correlate with species richness. Abiotic factors, in particular soil nitrogen concentration, explained about 50% of variability in aboveground biomass. The best model incorporating functional trait diversity explained only about 30%, while the best model based on aggregated trait values explained about 54% of variability in aboveground biomass. The inclusion of all predictor variable groups in a combined model increased the predictive power to about 75%. This model comprised soil nitrogen concentration as abiotic factor, aggregated traits being indicative for species competitive dominance (rooting depth, leaf distribution, specific leaf area, perennial life cycle) and functional trait diversity in vegetative plant height, leaf area and life cycle. Our study strongly suggests that abiotic factors, trait values of the dominant species and functional trait diversity i
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| [77] |
Fine-resolution forest tree height estimation across the Sierra Nevada through the integration of spaceborne LiDAR, airborne LiDAR, and optical imagery [J].https://doi.org/10.1080/17538947.2016.1227380 URL [本文引用: 1] 摘要
Forests of the Sierra Nevada (SN) mountain range are valuable natural heritages for the region and the country, and tree height is an important forest structure parameter for understanding the SN forest ecosystem. There is still a need in the accurate estimation of wall-to-wall SN tree height distribution at fine spatial resolution. In this study, we presented a method to map wall-to-wall forest tree height (defined as Lorey s height) across the SN at 70-m resolution by fusing multi-source datasets, including over 1600 in situ tree height measurements and over 1600 km2 airborne light detection and ranging (LiDAR) data. Accurate tree height estimates within these airborne LiDAR boundaries were first computed based on in situ measurements, and then these airborne LiDAR-derived tree heights were used as reference data to estimate tree heights at Geoscience Laser Altimeter System (GLAS) footprints. Finally, the random forest algorithm was used to model the SN tree height from these GLAS tree heights, optical imagery, topographic data, and climate data. The results show that our fine-resolution SN tree height product has a good correspondence with field measurements. The coefficient of determination between them is 0.60, and the root-mean-squared error is 5.45 m.
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| [78] |
Relationships among species traits: Separating levels of response and identifying linkages to abundance [J].https://doi.org/10.1890/0012-9658(2003)084[0001:RASTSL]2.0.CO;2 URL [本文引用: 2] 摘要
We test the idea that species interactions and environmental tolerances translate constrained traits to patterns of species distribution and abundance through a series of trade-offs. First, we suggest a framework to classify relationships among traits at different levels of organization. We then synthesize experiments to quantify relationships at these multiple levels for a group of 11 prairie plant species that characterize different disturbance regimes. Finally, we identify linkages among traits at these different levels and examine how these linkages relate plant traits to patterns of species composition following gap creation. Linkages were evident between all levels of response, lending credence to the idea that relationships among organismal traits can shape dynamics of species interactions and thereby translate into abundance patterns. Interestingly, the important trade-offs and translators for the set of species we examined were not always the ones predicted by conceptual models. For instance, we found evidence of trade-offs between measures of competitive and tolerance (to soil compaction) abilities, but little evidence of negative correlations between competitive abilities in different environments or between colonization and competitive abilities. Tolerance (to defoliation, shade, drought) and colonization abilities, rather than competitive ability, appeared to be important translators that linked organismal traits to abundance patterns. In addition, growth rates of the species under field conditions, but not other measures of demographic success (e.g., survival, seedbank density), were related to the species distributions due to soil disturbance. Although our results support the idea that trade-offs scale across several levels of organization, specific predictions of several well-known hypotheses are not borne out along all levels of organization and other, less emphasized trade-offs appear to be as important in our study system.
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| [79] |
Testing the Holy Grail framework: Using functional traits to predict ecosystem change [J].https://doi.org/10.1111/j.1469-8137.2008.02650.x URL PMID: 19138225 [本文引用: 2] 摘要
Field studies with transgenic Arabidopsis lines have been performed over 8 yr, to better understand the influence that certain genes have on plant performance. Many (if not most) plant phenotypes cannot be observed under the near constant, low-stress conditions in growth chambers, making field experiments necessary. However, there are challenges in performing such experiments: permission must be obtained and regulations obeyed, the profound influence of uncontrollable biotic and abiotic factors has to be considered, and experimental design has to be strictly controlled. The aim here is to provide inspiration and guidelines for researchers who are not used to setting up such experiments, allowing others to learn from our mistakes. This is believed to be the first example of a 'manual' for field experiments with transgenic Arabidopsis plants. Many of the challenges encountered are common for all field experiments, and many researchers from ecological backgrounds are skilled in such methods. There is huge potential in combining the detailed mechanistic understanding of molecular biologists with ecologists' expertise in examining plant performance under field conditions, and it is suggested that more interdisciplinary collaborations will open up new scientific avenues to aid analyses of the roles of genetic and physiological variation in natural systems.
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| [80] |
Distinguishing between the effects of species diversity and species composition [J].https://doi.org/10.2307/3546532 URL [本文引用: 2] 摘要
; Dept of Ecology, Evolution, and Behavior, Univ. of Minnesota, St. Paul, MN 55108, ETATS-UNIS02 0202 02 0202OIKSAA02 1997,02vol.0280,02n1,02[Note(s): p. 185]02(3 ref.)AnglaisBlackwell, Oxford, ROYAUME-UNI02 (1949) (Revue); ; ; ; ; ; ; ; ; ; ; ; ; ; ; INIST-CNRS, Cote INIST : 5651,0235400006768338.0240
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Causes, consequences and ethics of biodiversity [J].https://doi.org/10.1038/35012217 URL PMID: 10821280 [本文引用: 1] 摘要
The existence of so great a diversity of species on Earth remains a mystery, the solution to which may also explain why and how biodiversity influences the functioning of ecosystems. The answer may lie in quantifying the trade-offs that organisms face in dealing with the constraints of their environment. Societal responses to the loss of biodiversity also involve trade-offs, and the elaboration of these will be essential in developing wiser environmental ethics and policy.
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| [82] |
The influence of functional diversity and composition on ecosystem processes [J].https://doi.org/10.1126/science.277.5330.1300 URL [本文引用: 2] 摘要
Humans are modifying both the identities and numbers of species in ecosystems, but the impacts of such changes on ecosystem processes are controversial. Plant species diversity, functional diversity, and functional composition were experimentally varied in grassland plots. Each factor by itself had significant effects on many ecosystem processes, but functional composition and functional diversity were the principal factors explaining plant productivity, plant percent nitrogen, plant total nitrogen, and light penetration. Thus, habitat modifications and management practices that change functional diversity and functional composition are likely to have large impacts on ecosystem processes.
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| [83] |
A fully traits-based approach to modeling global vegetation distribution [J].https://doi.org/10.1073/pnas.1304551110 URL PMID: 25225413 [本文引用: 2] 摘要
Dynamic Global Vegetation Models (DGVMs) are indispensable for our understanding of climate change impacts. The application of traits in DGVMs is increasingly refined. However, a comprehensive analysis of the direct impacts of trait variation on global vegetation distribution does not yet exist. Here, we present such analysis as proof of principle. We run regressions of trait observations for leaf mass per area, stem-specific density, and seed mass from a global database against multiple environmental drivers, making use of findings of global trait convergence. This analysis explained up to 52% of the global variation of traits. Global trait maps, generated by coupling the regression equations to gridded soil and climate maps, showed up to orders of magnitude variation in trait values. Subsequently, nine vegetation types were characterized by the trait combinations that they possess using Gaussian mixture density functions. The trait maps were input to these functions to determine global occurrence probabilities for each vegetation type. We prepared vegetation maps, assuming that the most probable (and thus, most suited) vegetation type at each location will be realized. This fully traits-based vegetation map predicted 42% of the observed vegetation distribution correctly. Our results indicate that a major proportion of the predictive ability of DGVMs with respect to vegetation distribution can be attained by three traits alone if traits like stem-specific density and seed mass are included. We envision that our traits-based approach, our observation-driven trait maps, and our vegetation maps may inspire a new generation of powerful traits-based DGVMs.
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| [84] |
Ecosystem productivity can be predicted from potential relative growth rate and species abundance [J].https://doi.org/10.1111/j.1461-0248.2006.00958.x URL PMID: 16925655 [本文引用: 2] 摘要
Abstract We show that ecosystem-specific aboveground net primary productivity (SANPP, gg 611 day 611 , productivity on a per gram basis) can be predicted from species-level measures of potential relative growth rate (RGR max ), but only if RGR max is weighted according to the species’ relative abundance. This is in agreement with Grime's mass-ratio hypothesis. Productivity was measured in 12 sites in a French Mediterranean post-agricultural succession, while RGR max was measured on 26 of the most abundant species from this successional sere, grown hydroponically. RGR max was only weakly correlated ( r 2 =0.12, P <0.05) with field age when species abundance was not considered, but the two variables were strongly correlated ( r 2 =0.81, P <0.001) when the relative abundance of species in each field was taken into account. SANPP also decreased significantly with field age. This resulted in a tight relationship ( r 2 =0.77, P <0.001) between productivity and RGR max weighted according to species relative biomass contribution. Our study shows that scaling-up from the potential properties of individual species is possible, and that information on potential and realized species traits can be integrated to predict ecosystem functioning.
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| [85] |
New multidimensional functional diversity indices for a multifaceted framework in functional ecology [J].https://doi.org/10.1890/07-1206.1 URL [本文引用: 1] |
| [86] |
The emergence and promise of functional biogeography [J].https://doi.org/10.1073/pnas.1415442111 URL PMID: 25225414 [本文引用: 8] 摘要
Abstract Understanding, modeling, and predicting the impact of global change on ecosystem functioning across biogeographical gradients can benefit from enhanced capacity to represent biota as a continuous distribution of traits. However, this is a challenge for the field of biogeography historically grounded on the species concept. Here we focus on the newly emergent field of functional biogeography: the study of the geographic distribution of trait diversity across organizational levels. We show how functional biogeography bridges species-based biogeography and earth science to provide ideas and tools to help explain gradients in multifaceted diversity (including species, functional, and phylogenetic diversities), predict ecosystem functioning and services worldwide, and infuse regional and global conservation programs with a functional basis. Although much recent progress has been made possible because of the rising of multiple data streams, new developments in ecoinformatics, and new methodological advances, future directions should provide a theoretical and comprehensive framework for the scaling of biotic interactions across trophic levels and its ecological implications.
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| [87] |
The China plant trait database: Toward a comprehensive regional compilation of functional traits for land plants [J]. |
| [88] |
Latitudinal variation of leaf morphological traits from species to communities along a forest transect in eastern China [J].https://doi.org/10.1007/s11442-016-1251-x URL [本文引用: 1] 摘要
Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce. To explore the spatial patterns of leaf traits, we investigated leaf area (LA), leaf thickness (LT), specific leaf area (SLA), and leaf dry matter content (LDMC) across 847 species from nine typical forests along the North-South Transect of Eastern China (NSTEC) between July and August 2013, and also calculated the community weighted means (CWM) of leaf traits by determining the relative dominance of each species. Our results showed that, for all species, the means (± SE) of LA, LT, SLA, and LDMC were 2860.01 ± 135.37 mm 2 , 0.17 ± 0.003 mm, 20.15 ± 0.43 m 2 kg –1 , and 316.73 ± 3.81 mg g –1 , respectively. Furthermore, latitudinal variation in leaf traits differed at the species and community levels. Generally, at the species level, SLA increased and LDMC decreased as latitude increased, whereas no clear latitudinal trends among LA or LT were found, which could be the result of shifts in plant functional types. When scaling up to the community level, more significant spatial patterns of leaf traits were observed ( R 2 = 0.46–0.71), driven by climate and soil N content. These results provided synthetic data compilation and analyses to better parameterize complex ecological models in the future, and emphasized the importance of scaling-up when studying the biogeographic patterns of plant traits.
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| [89] |
The effect of inflorescence bud removal on tuber production in Helianthus tuberosus L. (Asteraceae) [J].https://doi.org/10.2307/1940858 URL [本文引用: 1] 摘要
I investigated allocation to sexual and asexual reproduction in the Jerusalem artichoke, Helianthus tuberosus L. (Asteraceae), a clonal pseudoannual that is an herbaceous ramet for one season, but propagates as a perennial through tubers that quickly dissociate from the parent plant. H. tuberosus ramets grown from tubers allocated 24% of their end-of-season biomass to tubers and 9% to sexual organs, with substantial variation attributable to four genetic lines cultured from eastern Iowa. Experimentally induced failure of sexual reproduction increased allocation to asexual reproduction under common garden conditions. Plants with inflorescence buds removed produced more (82 vs. 69) and larger (4.4 g vs. 3.8 g) tubers than those with unlimited sexual reproduction. Total biomass allocation to reproduction in plants receiving the bud-removal treatment was equivalent to combined allocation to sexual and asexual reproduction in plants that produced flower heads and achenes. This suggests a complete diversion of resources from sexual to asexual reproduction when sexual reproduction is thwarted. Aboveground plant size did not change with treatment. These results suggest a flexible life history that can respond to sexual failure resulting from low pollinator availability or damage to inflorescences from herbivory or weather, with enhanced facultative production of asexual tubers capable of sexual reproduction the following year. Hereditary variation in allocation leaves open the possibility of local adaptation.
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| [90] |
Strategy shifts in leaf physiology, structure and nutrient content between species of high-and low-rainfall and high-and low-nutrient habitats [J].https://doi.org/10.1046/j.0269-8463.2001.00542.x URL [本文引用: 1] |
| [91] |
Modulation of leaf economic traits and trait relationships by climate [J].https://doi.org/10.1111/j.1466-822x.2005.00172.x URL [本文引用: 3] 摘要
ABSTRACT Aim68 Our aim was to quantify climatic influences on key leaf traits and relationships at the global scale. This knowledge provides insight into how plants have adapted to different environmental pressures, and will lead to better calibration of future vegetation–climate models. Location68 The data set represents vegetation from 175 sites around the world. Methods68 For more than 2500 vascular plant species, we compiled data on leaf mass per area (LMA), leaf life span (LL), nitrogen concentration (N mass ) and photosynthetic capacity (A mass ). Site climate was described with several standard indices. Correlation and regression analyses were used for quantifying relationships between single leaf traits and climate. Standardized major axis (SMA) analyses were used for assessing the effect of climate on bivariate relationships between leaf traits. Principal components analysis (PCA) was used to summarize multidimensional trait variation. Results68 At hotter, drier and higher irradiance sites, (1) mean LMA and leaf N per area were higher; (2) average LL was shorter at a given LMA, or the increase in LL was less for a given increase in LMA (LL–LMA relationships became less positive); and (3) A mass was lower at a given N mass , or the increase in A mass was less for a given increase in N mass . Considering all traits simultaneously, 18% of variation along the principal multivariate trait axis was explained by climate. Main conclusions68 Trait-shifts with climate were of sufficient magnitude to have major implications for plant dry mass and nutrient economics, and represent substantial selective pressures associated with adaptation to different climatic regimes.
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| [92] |
The worldwide leaf economics spectrum [J].https://doi.org/10.1038/nature02403 URL [本文引用: 4] |
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Effects of grazing on leaf traits and ecosystem functioning in Inner Mongolia grasslands: scaling from species to community [J].https://doi.org/10.5194/bgd-6-9945-2009 URL [本文引用: 1] 摘要
More attention has focused on using some easily measured plant functional traits to predict grazing influence on plant growth and ecosystem functioning. However, there has been much controversy on leaf traits response to grazing, thus more research should be conducted at the species level. Here we investigated the leaf area, leaf mass and specific leaf area (SLA) of 263 species in eight grassland communities along a soil moisture gradient in the Xilin River Basin, a semiarid grassland of northern China, to explore the grazing effects on ecosystem functioning. Results demonstrated that grazing decreased the leaf area and leaf mass in more than 56% of species in the Xilin River Basin, however, responses of SLA to grazing varied widely between species. Grazing increased SLA in 38.4% of species, decreased SLA in 31.3% of species and had no effect on 30.3% of species. Annuals and biennials generally developed high SLA as grazing tolerance traits, while perennial graminoids developed low SLA as grazing avoidance traits. Considering the water ecotypes, the SLA-increased and SLA-unchanged species were dominated by hygrophytes and mesophytes, while the SLA-decreased species were dominated by xerophytes. At the community level, grazing decreased the mean leaf area index (LAI) of six communities by 16.9%, leaf biomass by 35.2% and standing aboveground biomass (SAB) by 35.0% in the Xilin River Basin, indicating that overgrazing greatly decreased the ecosystem functioning in the semi-arid grassland of northern China. Soil properties, especially fielding holding capacity and soil organic carbon and total nitrogen could mediate the negative grazing impacts. The results suggest SLA is a better leaf trait to reveal plant adaptability to grazing. Our findings have practical implications for range management and productivity maintenance in the semiarid grassland, and it is feasible to take some measures such as ameliorating soil water and nutrient availabilities to prevent grassland degradation.
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