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1.
The functional biogeography of tropical forests is expressed in foliar chemicals that are key physiologically based predictors of plant adaptation to changing environmental conditions including climate. However, understanding the degree to which environmental filters sort the canopy chemical characteristics of forest canopies remains a challenge. Here, we report on the elevation and soil‐type dependence of forest canopy chemistry among 75 compositionally and environmentally distinct forests in nine regions, with a total of 7819 individual trees representing 3246 species collected, identified and assayed for foliar traits. We assessed whether there are consistent relationships between canopy chemical traits and both elevation and soil type, and evaluated the general role of phylogeny in mediating patterns of canopy traits within and across communities. Chemical trait variation and partitioning suggested a general model based on four interconnected findings. First, geographic variation at the soil‐Order level, expressing broad changes in fertility, underpins major shifts in foliar phosphorus (P) and calcium (Ca). Second, elevation‐dependent shifts in average community leaf dry mass per area (LMA), chlorophyll, and carbon allocation (including nonstructural carbohydrates) are most strongly correlated with changes in foliar Ca. Third, chemical diversity within communities is driven by differences between species rather than by plasticity within species. Finally, elevation‐ and soil‐dependent changes in N, LMA and leaf carbon allocation are mediated by canopy compositional turnover, whereas foliar P and Ca are driven more by changes in site conditions than by phylogeny. Our findings have broad implications for understanding the global ecology of humid tropical forests, and their functional responses to changing climate. 相似文献
2.
植物物候是植物生活史中的重要性状,也是指示气候与自然环境变化的重要指标,现已成为全球变化领域的研究热点之一。传统物候研究多假设物候由气候因素决定,如气温、降水、光照等,并主要从植物物候的年际变化角度探讨了气候因素对物候特征的影响。然而,不同物种的物候存在较大差异表明植物物候还与自身生物学特性（如系统发育和功能性状）有关,但植物生物学特性如何影响植物物候仍缺乏深入研究。基于北京地区44种木本植物1965-2018年的展叶始期和开花始期观测资料,以展叶始期和开花始期的3类物候特征（平均物候期、物候对温度的响应敏感度和物候期的积温需求）为例,探究植物物候特征与系统发育和功能性状的关系。首先,利用系统发育信号Blomberg’s K和进化模型检验植物物候特征是否具有系统发育保守性,并通过系统发育信号表征曲线直观表达植物物候特征的进化模式;之后,利用广义估计方程分析植物生活型、传粉型与物候特征的关系,以揭示不同植物的资源利用方式及生存策略的差异。研究发现：（1）除展叶始期的温度敏感度外,其余物候特征的进化均受随机遗传漂变和自然选择力的共同作用,可推断物候特征具有系统发育保守性,即亲缘关系越近的物种物候特征越相似。（2）开花始期的系统发育信号强度比展叶始期更大,表明繁殖物候的系统发育可能比生长物候更保守。（3）植物展叶始期及其积温需求与生活型密切相关。灌木比乔木的展叶时间早、积温需求少。植物开花始期与传粉型相关,风媒植物开花显著早于虫媒植物。研究成果有助于深入理解物候变化的生物学机制,对于丰富物候学的理论研究有重要意义,同时对植物保护也具有重要的指导价值。 相似文献
3.
FILIPPO BUSSOTTI 《Global Change Biology》2008,14(11):2727-2739
Tropospheric ozone exercises pressure on vegetation in combination with other oxidative factors such as strong sunlight, UV‐B radiation, high temperatures and water shortage. The relationship established between these factors and the plants can be either antagonistic (cross‐resistance) or synergistic. Response mechanisms are activated involving physiological, chemical and morphological features. Overall sensitivity (or resistance) is determined by the amount of total oxidative pressure in relation to the plant's physiological plasticity [i.e. its ability (within its own resilience potential) to alter its structure and functions in order to react to the oxidative pressure]. Within different populations of the same species, functional leaf traits (leaf area and thickness, leaf mass per area or specific leaf area, tissue thickness) may vary in relation to the extent that the plant succeeds in acclimating to ambient oxidative pressure. The behaviour of a tree in an oxidative environment can be interpreted by means of leaf structure analysis. Leaves presenting high tissue density (and thus low intercellular space content) display a high degree of acclimation to stressors, react little to environmental changes and are characterized by remarkable longevity. Leaves of this type also have a high photosynthesis capacity per surface unit (due to the N content per surface unit) and a high PN/GW (or water use efficiency, WUE). Thus, they are able to support detoxification processes. These morphological traits are to be found in adult plants in late successional stands and, above all, in ambients that have already been subjected to oxidative pressure. However, in early successional species and during the dynamic stages of growth (e.g. in the renewal occurring along forest edges), it is the opposite leaf traits that prevail: low leaf density, high photosynthesis capacity per dry weight unit, low WUE, low leaf longevity. These traits make plants far more reactive to environmental changes (e.g. they exploit the light from sun flecks much more effectively), but enable them to achieve only a low degree of acclimation and a poor ability to support detoxification processes. Whereas adult forests display a high level of ecological resilience and have a relatively good tolerance of ozone, the renewal stages are (at least potentially) more vulnerable. In these environments, ozone can alter the competition among genotypes and favour more resistant ones. Among the sectors most at risk, we must include communities growing at the edge of their ecological range, for whom even a slight increase in oxidative pressure can trigger substantial degenerative processes. 相似文献
4.
A controlled experiment was conducted in order to understand how functional and structural traits of species with different leaf habits (Fraxinus ornus and Quercus ilex) shift as a consequence of nitrogen (N) addition (30 kg ha yr?1) and to explore the effect that N has on the water stress response. The experiment was divided in two stages: stage I, N addition under well-watered condition; stage II, N addition under drought. Functionality of the photosynthetic machinery, growth and biomass partitioning were assessed. The N content at leaf level increases in F. ornus only, which invests resources on photosynthetic machinery, whereas Q. ilex tends to store N in non-photosynthetic biomass, increasing relative growth rate and biomass, resulting in different allometric ratio. This effect may play a role in water stress response. Stomatal conductance of Q. ilex treated with N and subjected to water stress is lower relative to drought treatment. On the contrary, F. ornus takes advantage of N addition that has ameliorative effects on its functionality when drought was imposed. The obtained results, highlighting response mechanisms to multiple stress factors, should help to better understand and assess the performance of forest ecosystems under the foreseen environmental changes. 相似文献
5.
喀斯特退化天坑地下森林主要分布在不同坡向的倒石坡上,探究环境过滤、竞争排斥和随机过程在天坑地下森林群落构建中的作用,有助于揭示天坑物种避难所价值,为天坑植物多样性的保护及坑外地表生态恢复提供科学的参考。以云南沾益深陷塘退化天坑为例,综合运用功能性状生态学和系统发育方法,研究不同坡向植物群落的土壤环境特征、功能性状变异、系统发育信号及系统发育多样性。研究表明：（1）不同坡向土壤环境差异较大,相对于南坡和北坡而言,东坡的土壤环境变异程度最大。（2）各坡向具有不同的优势种群,其中壳斗科植物种群多度较大,在北坡和东坡的黄背栎（Quercus pannosa）种群数量较大,在南坡则是青冈（Cyclobalanopsis glauca）多度最大。各优势物种功能性状在不同坡向存在差异,整体上变异程度中等,但南坡优势物种变异程度最大。（3）叶宽、长宽比、叶厚度、比叶面积具有较强且显著的系统发育信号（K>1,P<0.05）,性状进化过程中受遗传因素影响较大;而叶长、叶面积、叶干重、叶干物质含量、最大树高系统发育信号弱（K<1）,性状进化过程中受生境因素影响较大。（4）各坡向植物群落构建过程由生态位理论的环境过滤和竞争排斥作用主导,坡向从北坡-东坡-南坡的转变过程中,植物群落构建中环境过滤作用逐渐减小,竞争排斥作用逐渐增大。北坡可能较长时间内都是以旱生型植物为主要建群种,而南坡则可能最终演替成亚热带湿润气候型的顶极群落。 相似文献
6.
We explored potential of morphological and anatomical leaf traits for predicting ecophysiological key functions in subtropical trees. We asked whether the ecophysiological parameters stomatal conductance and xylem cavitation vulnerability could be predicted from microscopy leaf traits. We investigated 21 deciduous and 19 evergreen subtropical tree species, using individuals of the same age and from the same environment in the Biodiversity‐Ecosystem Functioning experiment at Jiangxi (BEF‐China). Information‐theoretic linear model selection was used to identify the best combination of morphological and anatomical predictors for ecophysiological functions. Leaf anatomy and morphology strongly depended on leaf habit. Evergreen species tended to have thicker leaves, thicker spongy and palisade mesophyll, more palisade mesophyll layers and a thicker subepidermis. Over 50% of all evergreen species had leaves with multi‐layered palisade parenchyma, while only one deciduous species (Koelreuteria bipinnata) had this. Interactions with leaf habit were also included in best multi‐predictor models for stomatal conductance (gs) and xylem cavitation vulnerability. In addition, maximum gs was positively related to log ratio of palisade to spongy mesophyll thickness. Vapour pressure deficit (vpd) for maximum gs increased with the log ratio of palisade to spongy mesophyll thickness in species having leaves with papillae. In contrast, maximum specific hydraulic conductivity and xylem pressure at which 50% loss of maximum specific xylem hydraulic conductivity occurred (Ψ50) were best predicted by leaf habit and density of spongy parenchyma. Evergreen species had lower Ψ50 values and lower maximum xylem hydraulic conductivities. As hydraulic leaf and wood characteristics were reflected in structural leaf traits, there is high potential for identifying further linkages between morphological and anatomical leaf traits and ecophysiological responses. 相似文献
7.
为探究不同校准方法和不同穿刺针直径作用下叶片穿透力测定结果是否存在差异,以及该结果与叶片功能性状之间的关系,选取了30种双子叶植物,分别测定其2.0、1.0、0.5 mm穿刺针直径下的穿透力、撕裂力和叶片的功能性状等指标。结果表明：（1）叶片穿透力在3种不同穿刺针直径作用下差异显著（P<0.05）,其在以周长校准方法下,同一物种在穿刺针直径0.5与1.0 mm的差异显著性占所有物种之比为76%、0.5 mm与2.0 mm为76%、1.0 mm与2.0 mm为33%（P<0.05）;而同样在以横截面积校准下则为66%、56%、30%（P<0.05）。（2）不同校准方法下3种穿刺针直径之间的叶片穿透力在同一生活型中差异不显著,而在草本分别与灌木和乔木等不同生活型中差异显著（P<0.05）,同时0.5 mm直径针的穿透力均大于1.0 mm和2.0 mm。（3）叶片穿透力与叶片角质层厚度、叶片厚度、撕裂力呈显著正相关（P<0.05）,与比叶面积呈显著负相关（P<0.05）,且以针周长校准的穿透力与叶片功能性状的相关性强于以横截面积校准的穿透力,而不同直径穿刺针作用下的叶片穿透力与叶片性状间的关系无显著差异。因此,穿刺针直径和校准方法的不同对叶片穿透力测定结果均产生差异,不同穿刺针直径测定的差异不会影响穿透机械力与叶片功能性状的相关关系,而不同校准方法测定的差异会影响穿透机械力与叶片功能性状相关关系的强弱。综上所述,在叶片穿透力测试中,选取合适的校准方法和穿刺针直径有利于提高数据的规范化和准确性,在此建议在两种校准方法下首先选用以针周长校准的方法,在3种穿刺针直径中选用0.5 mm测量叶面积小、叶脉密度大且较薄的叶片,对于叶面积大、叶脉密度大且较硬的叶片则选用2.0 mm。 相似文献
8.
植物功能生态学是研究植物种类间或环境梯度内植物某一功能性状变化,阐释其进化意义或生态意义的生态学分支学科;围绕3个主题开展工作:(1)利用功能性状作为研究解释的变量,(2)在种类间,清晰地进行性状比较,表述一般趋势,(3)在环境梯度内,清晰或模糊地比较性状的变化.性状是指从细胞到整个有机体个体水平的可测度的任何形态、生理、物候特点,不包括任何其它生物层次和环境因素.性状一般分为功能性状、表现性状等;功能性状是指对有机体表现产生强烈影响的性状,表现性状为反应功能性状作用和变化、并指示植物适合度的性状.功能性状研究不限于个体水平,现在已广泛联系了群落和生态系统过程与功能,正在开创植物生态学研究的一个崭新领域.比较是功能生态学的研究手段和途径.中国植物和植被研究基础丰富,开展中国植物区系的植物功能性状研究将积极贡献于功能生态学发展,种系发生途径和地理分布途径可能是功能生态学研究的全新视角. 相似文献
9.
叶片气孔不仅是植物平衡光合-蒸腾关系的重要门户,也是影响大气碳循环与水循环的关键结构。分析热岛效应下福州市乔木、灌木、草本3种生活型和常绿、落叶2种叶习性植物的气孔性状间的差异及其与其他叶功能性状间的权衡关系有助于探究不同类型植物在热环境下的适应策略。以福州市区的自然和半自然植被为研究对象,测定441个植物样本的气孔特征、化学计量特征和形态特征,结果表明：（1）3种生活型、2种叶习性植物的气孔长度（SL）、气孔密度（SD）差异显著（P<0.05）,潜在气孔导度指数（PCI）不存在显著差异（P>0.05）。草本的SL高于灌木和乔木,乔木的SD最高,灌木次之,草本最低;落叶植物的SL高于常绿植物,SD低于常绿植物。（2）SL与SD间的权衡关系稳定存在于3种生活型和2种叶习性植物中,且随着不同生活型和落叶习性植物的生态策略而呈现各异的权衡特征,即当SL一定时,乔木的SD最大,灌木的SD最小,常绿植物的SD大于落叶植物。（3）气孔性状和叶片形态、化学计量特征紧密联系,SL与比叶面积（SLA）正相关（P<0.01）,与叶面积（LA）负相关（P<0.01）;SD与叶氮含量（LNC）、叶磷含量（LPC）、SLA负相关（P<0.01）,与LA正相关（P<0.01）;PCI与LNC、SLA负相关（P<0.01）,与叶厚度（LT）正相关（P<0.05）。（4）复杂的环境是气孔性状变异的重要驱动因素,SL、PCI均与年均温（MAT）负相关（P<0.05）。 相似文献
10.
草原灌丛化通过改变物种之间的相互作用深刻影响着群落的结构和功能。然而,当前有关灌木如何影响不同功能群草本植物对矿质元素吸收和累积的研究仍明显不足。在内蒙古草原沿干旱梯度选取了4个研究地点,对比分析了小叶锦鸡儿(Caragana microphylla)灌丛斑块内和斑块外群落中禾草和非禾草功能群植物叶中矿质元素浓度以及地上生物量生产的差异,旨在阐明干旱和灌木对群落草本植物叶元素累积的影响,揭示灌草间相互作用的元素利用特征及其随干旱梯度的变化。结果显示：1)随干旱加剧,灌丛斑块内的非禾草功能群植物地上生物量保持恒定,但叶中的K、Ca、Mg、Fe、Mn和Cu元素浓度显著增加(P<0.05)。该结果表明群落中的非禾草功能群植物通过提高叶中的矿质元素水平来抵御和适应干旱胁迫。2)随干旱加剧,灌丛对非禾草功能群植物地上生物量,叶中Ca、Fe、Cu和Zn,禾草功能群植物叶中的P的累积影响从负(RII<0)或中性(RII=0)转变为正效应(RII>0)。该结果与胁迫梯度假说相符,表明灌木对草本植物的促进效应随干旱胁迫加剧而增加。3)灌丛的“沃岛”效应是驱动灌木对草本植物元素累积正效应... 相似文献
11.
植物功能性状可有效反映植物代谢活动、生物化学组成以及养分吸收等特征。本研究通过分析北京周边山地苔草属和委陵菜属植物的功能性状数据,得出结论如下:(1)植株高度、叶长度、叶宽度、花长度、比叶面积和叶片氮、磷含量之间具有正相关的关系,叶厚度、叶干重与其他性状呈负相关。(2)系统进化因素是导致植株高度、叶长度和叶片总氮含量产生差异性的内在因素。(3)随着海拔升高,植株变矮小,花朵变小,叶片变窄,比叶面积更小,叶片总氮、总磷也变少,叶片变得更厚更重。综合来看,海拔和系统进化对苔草属和委陵菜属功能性状的影响基本相同,只有比叶面积与系统进化的关系在两属中出现差异。 相似文献
12.
Wenzel Kr?ber Isa Plath Heike Heklau Helge Bruelheide 《Journal of visualized experiments : JoVE》2015,(104)
Leaf functional traits are important because they reflect physiological functions, such as transpiration and carbon assimilation. In particular, morphological leaf traits have the potential to summarize plants strategies in terms of water use efficiency, growth pattern and nutrient use. The leaf economics spectrum (LES) is a recognized framework in functional plant ecology and reflects a gradient of increasing specific leaf area (SLA), leaf nitrogen, phosphorus and cation content, and decreasing leaf dry matter content (LDMC) and carbon nitrogen ratio (CN). The LES describes different strategies ranging from that of short-lived leaves with high photosynthetic capacity per leaf mass to long-lived leaves with low mass-based carbon assimilation rates. However, traits that are not included in the LES might provide additional information on the species'' physiology, such as those related to stomatal control. Protocols are presented for a wide range of leaf functional traits, including traits of the LES, but also traits that are independent of the LES. In particular, a new method is introduced that relates the plants’ regulatory behavior in stomatal conductance to vapor pressure deficit. The resulting parameters of stomatal regulation can then be compared to the LES and other plant functional traits. The results show that functional leaf traits of the LES were also valid predictors for the parameters of stomatal regulation. For example, leaf carbon concentration was positively related to the vapor pressure deficit (vpd) at the point of inflection and the maximum of the conductance-vpd curve. However, traits that are not included in the LES added information in explaining parameters of stomatal control: the vpd at the point of inflection of the conductance-vpd curve was lower for species with higher stomatal density and higher stomatal index. Overall, stomata and vein traits were more powerful predictors for explaining stomatal regulation than traits used in the LES. 相似文献
13.
以民勤绿洲—荒漠过渡带20种主要植物为研究对象,通过对叶片6个功能性状的测定,分析荒漠植物叶性状的变异及相关性,比较不同功能群植物叶性状的差异性,探讨荒漠植物对环境的适应性,为该地区植被的恢复和重建提供理论依据。结果表明：①叶性状存在种间差异且变异程度不同,变异范围为14.11%~47.63%,叶绿素含量（ChlC）变异系数最大,叶片全氮含量（LCC）变异系数最小。②叶干物质含量（LDMC）与ChlC、LCC均呈极显著正相关（P＜0.01）,ChlC与LCC呈极显著正相关（P＜0.01）,其他叶性状间相关性不显著。③不同功能群植物叶性状存在显著差异。其中,豆科植物叶片LDMC、ChlC、LCC极显著高于藜科植物（P＜0.01）。草本植物叶片比叶面积（SLA）极显著高于灌木植物叶片（P＜0.01）。一年生植物叶片SLA、LNC显著高于多年生植物（P＜0.05）;多年生植物叶片LDMC极显著高于一年生植物（P＜0.01）;多年生植物叶片C含量显著高于一年生植物（P＜0.05）。C3植物叶片LDMC、ChlC显著高于C4植物（P＜0.05）;C4植物叶片δ13C极显著高于C3植物 （P＜0.01）;C3植物叶片LCC极显著（P＜0.01）高于C4植物。 相似文献
14.
为探究了哥王Wikstroemiaindica的叶功能性状特征及其影响因素,在海岛植被调查的基础上对了哥王叶片进行取样并测定其功能性状指标,利用变异系数法和Pearson相关性分析探讨叶功能性状之间的差异与联系,运用冗余分析研究了哥王叶功能性状对土壤因子的响应。结果表明,了哥王的叶功能性状变异系数介于9.76%～23.73%,其中叶体积变异幅度最大(23.73%),叶干物质含量变异幅度最小(9.76%),整体上了哥王叶功能性状保持相对稳定。了哥王各项叶功能性状之间具有一定的相关性,联系较密切。了哥王叶功能性状主要受土壤中有机质、全氮、碱解氮的影响,土壤中有机质、全氮、碱解氮的含量与比叶面积呈正比,与叶厚度、叶体积成反比。了哥王的叶片可以通过一定的性状变异和组合来适应外部环境的变化,以较好地适应海岛恶劣的环境。该研究结果可为了哥王野生种质资源的保护、利用以及人工栽培提供参考。 相似文献
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Aims Within-community variation accounts for a remarkable proportion of the variation in leaf functional traits. Plant height may be used to explain within-community variances of leaf traits because different microenvironments, especially light intensity, may occur at different heights. This study determines whether or not leaf nitrogen (N) and phosphorus (P) contents as well as leaf mass per area (LMA) are interspecifically correlated with the adult height of forest woody species. We also discuss these relationships with respect to community structure and functions of the ecosystem.Methods A total of 136 dicotyledonous woody species from 6 natural forests (3 evergreen and 3 deciduous ones) in East China (18°44′–45°25′N, 108°50′–128°05′E) were investigated. For each of the 157 species–site combinations, 6 traits were measured: plant adult height relative to the forest canopy (H R), leaf N and P contents per unit area (N area and P area), N and P contents per unit dry mass (N mass and P mass) and LMA. The total variances of each leaf trait across sites were partitioned in a hierarchical manner. The relationships between leaf traits and H R within forest communities were then analyzed using both standardized major axis regression and Felsenstein's phylogenetic independent contrasts. Relationships between evergreen and deciduous forests were compared by linear mixed models.Important findings H R is a robust predictor of leaf N area, P area and LMA, explaining 36.7, 39.4 and 12.0% of their total variations across forests, respectively. Leaf N area, P area and LMA increased with H R in all of the studied forests, with slopes that were steeper in evergreen forests than in deciduous ones. Leaf N mass and P mass showed no significant relationship with H R generally. The increase in leaf N area, P area and LMA with H R across species is assumed to maximize community photosynthesis and may favor species with larger H R . 相似文献
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以内蒙古典型草原为研究对象,选取放牧和割草、去除放牧、去除放牧和割草样地进行群落调查和叶片属性测量,比较分析各样地土壤性质、群落生产力及主要物种的比叶面积(SLA,Specific Leaf Area)、叶片干物质含量(LDMC,Leaf Dry Matter Content)、叶片氮含量(LNC,Leaf Nitrogen Concentration)在个体、功能群和群落水平对去除干扰的响应。结果表明,1)去除干扰处理在短期对土壤特性和群落生产力的影响不显著;2)多数物种在放牧和割草样地SLA较低,说明典型草原多数物种的SLA表现为放牧逃避;3)不同功能群植物叶片属性对去除干扰的响应不一致,去除放牧后,多年生杂类草的SLA和LDMC不受影响,但LNC变小;多年生禾草的SLA增加,而LDMC和LNC无显著变化。一年生植物在去除放牧和割草后,LNC显著增加。去除割草后,多年生禾草SLA减小,而多年生杂类草SLA、LNC增加,LDMC减小;4)在群落水平,放牧和割草样地由于较占优势的多年生禾草SLA较低,群落比叶面积最低,在去除放牧和割草样地,群落叶片氮含量显著增加;5)在内蒙古典型草原,LDMC能够很好地将多年生禾草和多年生杂类草区分,SLA在个体、功能群和群落水平均比LDMC敏感。 相似文献
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18.
群落构建是生态学研究中的论题之一,对湿地植物进行群落构建研究将会对湿地植物的修复与重建工作具有重要意义。为探究城市沿江湿地植物群落构建主要驱动力,以闽江福州段湿地为例,选取四个典型城市沿江湿地公园,基于系统发育结合功能性状的方法,测定其样地植物地上、地下功能性状与土壤因子,并且构建系统发育树、检测系统发育信号、并计算系统发育指数。结果表明:(1)土壤因子与植物功能性状在四个湿地间都具有显著差异,土壤电导率与比根长的变异性最大。土壤含水量与是影响植物性状变异的主要因素。(2)除叶全氮含量外,其余7个功能性状未检测出明显的系统发育信号,植物功能性状表现为趋同。(3)甘蔗湿地与乌龙江湿地的系统发育结构趋于发散,群落构建的主要驱动力为环境过滤。塔礁洲湿地与闽江河口湿地的系统发育结构表现为聚集,限制相似性为主要驱动因素。总体而言闽江福州段湿地植物群落构建过程由生态位理论主导,环境过滤和相似性限制为主要驱动因素,土壤含水量作为主要的环境筛选影响着闽江福州段湿地植物群落构建过程。不同生境下生态位分化的驱动因素不同,植物功能性状的种间种内变异反映了植物对环境异质性的响应机制。 相似文献
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Jinshi Xu Yu Chen Lixia Zhang Yongfu Chai Mao Wang Yaoxin Guo Ting Li Ming Yue 《Ecology and evolution》2017,7(14):5056-5069
Community assembly processes is the primary focus of community ecology. Using phylogenetic‐based and functional trait‐based methods jointly to explore these processes along environmental gradients are useful ways to explain the change of assembly mechanisms under changing world. Our study combined these methods to test assembly processes in wide range gradients of elevation and other habitat environmental factors. We collected our data at 40 plots in Taibai Mountain, China, with more than 2,300 m altitude difference in study area and then measured traits and environmental factors. Variance partitioning was used to distinguish the main environment factors leading to phylogeny and traits change among 40 plots. Principal component analysis (PCA) was applied to colligate other environment factors. Community assembly patterns along environmental gradients based on phylogenetic and functional methods were studied for exploring assembly mechanisms. Phylogenetic signal was calculated for each community along environmental gradients in order to detect the variation of trait performance on phylogeny. Elevation showed a better explanatory power than other environment factors for phylogenetic and most traits’ variance. Phylogenetic and several functional structure clustered at high elevation while some conserved traits overdispersed. Convergent tendency which might be caused by filtering or competition along elevation was detected based on functional traits. Leaf dry matter content (LDMC) and leaf nitrogen content along PCA 1 axis showed conflicting patterns comparing to patterns showed on elevation. LDMC exhibited the strongest phylogenetic signal. Only the phylogenetic signal of maximum plant height showed explicable change along environmental gradients. Synthesis. Elevation is the best environment factors for predicting phylogeny and traits change. Plant's phylogenetic and some functional structures show environmental filtering in alpine region while it shows different assembly processes in middle‐ and low‐altitude region by different trait/phylogeny. The results highlight deterministic processes dominate community assembly in large‐scale environmental gradients. Performance of phylogeny and traits along gradients may be independent with each other. The novel method for calculating functional structure which we used in this study and the focus of phylogenetic signal change along gradients may provide more useful ways to detect community assembly mechanisms. 相似文献
20.
群落构建一直是生态学研究的热点,基于系统发育和功能性状量化生境过滤、竞争排斥以及随机过程在群落构建中的作用,能够深入理解群落构建机制。本研究以长白山针阔混交林不同演替阶段的3个5.2 hm~2样地(次生杨桦林、次生针阔混交林、原始椴树红松林)为平台,基于被子植物分类系统Ⅲ(Angiosperm Classification System,APGⅢ)构建的系统发育树和7个关键功能性状(叶面积、比叶面积、叶片厚度、叶片氮含量、叶片磷含量、氮磷比、最大树高),结合环境数据,分析不同演替阶段群落系统发育和功能性状结构。研究表明:(1)各演替阶段7个植物功能性状都表现出显著的系统发育信号,表明植物功能性状受系统发育历史影响;(2)系统发育和功能性状结构在不同演替阶段和不同径级均为非随机状态。随着演替的推进群落系统发育和功能性状结构由聚集走向发散;随着径级的增加,系统发育和功能性状结构的聚集程度减小,表明随着演替阶段的进行和径级增大,竞争性排斥的作用逐渐明显;(3)各演替阶段系统发育和功能性状的周转都为非随机且不同因子对两者的解释力度存在差异。演替早期空间距离的解释力度小于环境距离,说明生境过滤在群落构建中的重要性,而在演替后期空间距离的解释力度大于环境距离,验证了扩散限制在群落构建中的重要性。 相似文献