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1.
Species ranges have been shifting since the Pleistocene, whereby fragmentation, isolation, and the subsequent reduction in gene flow have resulted in local adaptation of novel genotypes and the repeated evolution of endemic species. While there is a wide body of literature focused on understanding endemic species, very few studies empirically test whether or not the evolution of endemics results in unique function or ecological differences relative to their widespread congeners; in particular while controlling for environmental variation. Using a common garden composed of 15 Eucalyptus species within the subgenus Symphyomyrtus (9 endemic to Tasmania, 6 non-endemic), here we hypothesize and show that endemic species are functionally and ecologically different from non-endemics. Compared to non-endemics, endemic Eucalyptus species have a unique suite of functional plant traits that have extended effects on herbivores. We found that while endemics occupy many diverse habitats, they share similar functional traits potentially resulting in an endemic syndrome of traits. This study provides one of the first empirical datasets analyzing the functional differences between endemics and non-endemics in a common garden setting, and establishes a foundation for additional studies of endemic/non-endemic dynamics that will be essential for understanding global biodiversity in the midst of rapid species extinctions and range shifts as a consequence of global change.  相似文献   

2.
太岳山典型阔叶乔木冠层叶片性状的分布格局   总被引:1,自引:1,他引:0  
以太岳山4种阔叶乔木不同冠层高度的叶片为研究对象,用LI-3000A叶面积仪和Li-6400便携式光合作用测定系统分别测定了这4种乔木不同冠层高度叶片的叶面积大小和单位面积的叶光饱和速率(Aarea);同时测定了其叶氮含量;计算了其比叶面积(SLA)、单位面积叶氮含量(Narea)、单位重量叶氮含量(Nmass)、单位重量的叶光饱和速率(Amass)和光合氮素利用效率(PNUE),对植株不同冠层高度叶片的SLA、叶氮和光合特性的空间分布格局进行了比较研究,结果表明:Aarea、Amass、Nmass、PNUE、SLA和Narea在树冠上层、中层和下层的差异均达到了极显著水平(P<0.001),表明树冠不同高度的叶片性状参数差异较大;在相同SLA下,Nmass和Narea在冠层中的分布均表现为中层>上层>下层,并出现平行位移现象;Aarea和Nmass都以中层值最大,表明冠层光合能力分布格局以中层相对较高。  相似文献   

3.
Despite extensive research, factors influencing the importance of pre- and post-settlement processes to recruitment variability remain ambiguous. Using a novel perspective, we investigated the potential influence of endemism on the relationship between larval supply and recruitment in reef fish populations at Lord Howe Island, Australia. Larval supply and recruitment were measured for three regional endemic and four widespread non-endemic species using light traps, artificial collectors, and underwater visual censuses. Recruitment was correlated with larval supply in endemics but not in non-endemics, likely due to a combination of low larval supply and post-settlement survival of non-endemics. Surveys also indicated that endemics were far more abundant and occurred in more locations than closely related non-endemics. These preliminary findings suggest that either local adaptation enhances recruitment in endemics through higher larval replenishment rates or reduced post-settlement mortality, populations of widespread species at the periphery of their range are poorly adapted to local environmental conditions and therefore experience lower and more variable settlement and post-settlement survival rates, or both.  相似文献   

4.
Current models of island biogeography treat endemic and non-endemic species as if they were functionally equivalent, focussing primarily on species richness. Thus, the functional composition of island biotas in relation to island biogeographical variables remains largely unknown. Using plant trait data (plant height, leaf area and flower length) for 895 native species in the Canary Islands, we related functional trait distinctiveness and climate rarity for endemic and non-endemic species and island ages. Endemics showed a link to climatically rare conditions that is consistent with island geological change through time. However, functional trait distinctiveness did not differ between endemics and non-endemics and remained constant with island age. Thus, there is no obvious link between trait distinctiveness and occupancy of rare climates, at least for the traits measured here, suggesting that treating endemic and non-endemic species as functionally equivalent in island biogeography is not fundamentally wrong.  相似文献   

5.
Factors that contribute to interspecific variation in photosynthetic nitrogen-use efficiency (PNUE, the ratio of CO2 assimilation rate to leaf organic nitrogen content) were investigated, comparing ten dicotyledonous species that differ inherently in specific leaf area (SLA, leaf area:leaf dry mass). Plants were grown hydroponically in controlled environment cabinets at two irradiances (200 and 1000 μmol m–2 s–1). CO2 and irradiance response curves of photosynthesis were measured followed by analysis of the chlorophyll, Rubisco, nitrate and total nitrogen contents of the leaves. At both irradiances, SLA ranged more than twofold across species. High-SLA species had higher in situ rates of photosynthesis per unit leaf mass, but similar rates on an area basis. The organic N content per unit leaf area was lower for the high-SLA species and consequently PNUE at ambient light conditions (PNUEamb) was higher in those plants. Differences were somewhat smaller, but still present, when PNUE was determined at saturating irradiances (PNUEmax). An assessment was made of the relative importance of the various factors that underlay interspecific variation in PNUE. For plants grown under low irradiance, PNUEamb of high-SLA species was higher primarily due to their lower N content per unit leaf area. Low-SLA species clearly had an overinvestment in photosynthetic N under these conditions. In addition, high SLA-species allocated a larger fraction of organic nitrogen to thylakoids and Rubisco, which further increased PNUEamb. High-SLA species grown under high irradiance showed higher PNUEamb mainly due to a higher Rubisco specific activity. Other factors that contributed were again their lower contents of Norg per unit leaf area and a higher fraction of photosynthetic N in electron transport and Rubisco. For PNUEmax, differences between species in organic leaf nitrogen content per se were no longer important and higher PNUEmax of the high SLA species was due to a higher fraction of N in␣photosynthetic compounds (for low-light plants) and a higher Rubisco specific activity (for high-light grown plants). Received: 11 October 1997 / Accepted: 9 April 1998  相似文献   

6.
The objective of this study is to examine whether habitat, herbivory and traits related to resource acquisition, resource conservation, reproduction and dispersal differ between narrow endemic plant species and their widespread congeners. We undertook pairwise contrasts of 25 ecological characteristics and biological traits in 20 congeneric pairs of narrow endemic and widespread plant species in the French Mediterranean region. Within each pair, the two species had the same life-form, pollination mode and dispersal mode. Endemic species differed significantly from widespread congeners for a number of attributes. Endemic species occur in habitats on steeper slopes, with higher rock cover and in lower and more open vegetation than their widespread congeners. Endemic species are significantly smaller than widespread species, but show no differences in traits related to resource acquisition (specific leaf area, leaf nitrogen content, maximum photosynthetic rate) or resource conservation (leaf dry matter content). After accounting for their smaller stature, endemic species produce fewer and smaller flowers with less stigma-anther separation and lower pollen/ovule ratios and produce fewer seeds per plant than their widespread congeners. No consistent variation in seed mass and propagule structure was found between congeneric species. Herbivory levels did not differ between congeneric species. Ecological characteristics, notably the occupation of rocky habitats with low aboveground competition, may thus have played an important role in the differentiation of narrow endemic species in the Western Mediterranean. Morphological and ecophysiological traits of narrow endemic species indicate that they are not more stress-tolerant than their widespread congeners. Lower investment in pollen transfer and seed production suggest that local persistence is a key feature of the population ecology of narrow endemic species.  相似文献   

7.
Taking Elaeagnus mollis Diels and seven dominant woody species in its community from Yicheng County of Shanxi Province as research objects, leaf traits including specific leaf area (SLA), nitrogen content in leaf per unit area ( Narea ) , leaf dry matter content ( LDMC ) and photosynthetic nitrogen use efficiency ( PNUE ) were compared, and correlations of SLA value with LDMC and PNUE values were analyzed. The results show that there are different degree variations in four indexes of leaf traits of E. mollis, Vitex negundo var. heterophylla ( Franch.) Rehd., Broussonetia papyrifera ( Linn.) L' Hér. ex Vent., Lespedeza bicolor Turcz., Caragana microphylla Lam., Rosa xanthina Lindl., Amygdalus davidiana ( Carrière) de Vos ex Henry and Periploca sepium Bunge, in which, SLA value with the largest coefficient of variation ( 404%) , and LDMC value with the lowest coefficient of variation ( 103%) . Compared with other tested species, SLA and PNUE values of E. mollis are the lowest ( 103 cm-2 · g-1 and 108 μmol · mol-1 · s-1 , respectively) , while its Narea value is the highest ( 0243 g · m-2 ) , and its LDMC value is also relatively high ( 0380 g·g-1 ) . SLA value of eight tested species show an extremely significant positive correlation ( P<001) with PNUE value, and a significant negative correlation ( P<005 ) with LDMC value, correlation coefficient are 0923 and -0718, respectively, indicating that SLA value is an important parameter of leaf photosynthetic capacity and resource utilization ability. It is suggested that compared with other dominant woody species, E. mollis is more sensitive to environmental change, and has a poor environmental adaptability.  相似文献   

8.
植物的生理生态特征决定了植物在生态系统中的分布模式和物种的丰度。本文在开展样地调查的基础上,应用Li-6400光合测定系统研究了海南岛热带山地雨林原始林3个层次的6个优势种与9个伴生种幼树的光合作用参数,并测定了相应叶片的比叶面积(SLA)和氮、磷含量。15个种的SLA为38.2~143.7 cm2·g-1、单位面积最大光合速率(A-area)为2.77~7.61 μmol·m-2·s-1、单位干重最大光合速率(A-mass)为21.2~83.4 μmol·kg-1·s-1,单位面积暗呼吸速率(Rd-area)为0.02~1.15 μmol·m-2·s-1、单位干重暗呼吸速率(Rd-mass)为0.19~12.61 μmol·kg-1·s-1,光补偿点(LCP)为2.5~32.2 μmol·m-2·s-1,表观量子效率(Ф)为0.006 6~0.042 8 μmol·μmol-1 photon,叶片氮(LN)含量为7.98~23.63 mg·g-1,叶片磷(LP)含量为3.98~13.40 mg·g-1。中上层种的幼树具有较高的比叶面积、单位干重最大光合速率和表观量子效率;上层种的暗呼吸速率最低;幼树叶片的氮、磷含量随物种成树所在层次升高而减少,次序为下层种>中层种>上层种,但差异均不显著(P>0.05)。优势种和伴生种的光响应参数与SLA存在相关关系。伴生种的LN与SLA正相关(P<0.01),LP与SLA负相关(P<0.05);优势种的LN、LP与SLA不相关(P>0.05)。  相似文献   

9.
《植物生态学报》2014,38(10):1029
Aims Grassland desertification is being accelerated because of adverse climate change effects and unsustainable land uses, resulting in several major environmental problems. However, there are few studies on the economics spectrum of different plant functional types in desert steppe. The objectives of the current study are to examine the relationships among leaf functional traits of native plant species, to compare the functional traits among different plant functional types, and to determine whether an economic spectrum exists for the majority of species in the desert steppe of Damao Banner, Nei Mongol, China.
Methods Photosynthetic and chlorophyll fluorescence parameters, specific leaf area (SLA), and leaf nitrogen contents across 24 species of different functional types were measured in situ in the desert steppe ecosystem. Non-parametric tests were used to analyze leaf trait differences in plant species of different functional types. Linear regression analysis was used to determine the relationships among leaf traits in different plant species. Finally, a comprehensive analysis on these leaf traits in different plant species was conducted using the principal component analysis. All data analyses were performed using SPSS 16.0 (SPSS, Chicago, USA).
Important findings Significant differences among plant functional types were found in most of the leaf traits. SLA and mass-based nitrogen concentration (Nmass) in grasses were 2.39 and 1.20 folds, respectively, of that in shrubs; area-based photosynthetic capacity (Aarea), SLA, and photosynthetic nitrogen use efficiency (PNUE) in annual species were 1.93, 2.13, and 4.24 folds, respectively, of that in perennial species; and Aarea, SLA, and PNUE in C4 species were 2.25, 1.73, and 3.61 folds, respectively, of that in C3 species. Almost all relationships significantly differed (p < 0.01) among the leaf traits, with exception of the relationships between Aarea and area-based nitrogen concentration (Narea) and between quantum yield of PSII electron transport (ΦPSII) and SLA, implying that an economic spectrum may exist in the desert steppe ecosystem. The relationships of Narea, mass-based photosynthetic capacity (Amass), and PNUE with SLA were most significantly strong (R2 = 0.54, 0.62, 0.60, respectively; p < 0.01). Results in this study suggest that the annuals, grasses, and C4 species might be located at the end of the leaf economic spectrum with high area-based photosynthetic rate, high nitrogen concentration on mass basis, short leaf lifespan, and high SLA; whereas the perennials, shrubs, and C3 species could be located at the another end of the economic spectrum with contrasting traits.  相似文献   

10.
Among various potential causes of rarity, one explanation could be that a rare species has more narrow physiological tolerances to important environmental variables than does a widespread species. To test this hypothesis photosynthetic performance as a function of irradiance and temperature was compared for the rare cedar glade endemic Echinacea tennesseensis and its widespread prairie congener E. angustifolia following various light and soil moisture preconditioning regimes. Although the species differed in some morphological characteristics such as specific leaf area, both species demonstrated similar photosynthetic light-response curves on a leaf area basis, with low to moderate photosynthetic capacity. Thus no photosynthetic differences were found that could account for the contrasting geographic distributions of the endemic species and its widespread congener.  相似文献   

11.
A random process may control the number of endemic species   总被引:1,自引:0,他引:1  
The richness of endemic species is often recognized as an indication of the distinctiveness of certain local faunas and is used for the definition of conservation hotspots as well. Faunas of different animal taxa were considered in sets of contiguous geographical units. Comparing the faunas of different units in one set, we found an exponential increase in the number of endemics when plotted against the number of non-endemics. A model of independent stochastic population dynamics under the control of environmental oscillations produces random fluctuations in the ranges of species. Ranges of endemic species are supposedly narrower than ranges of co-occurring non-endemic species. In such a case, the flow of a random process leads to an exponential relationship between numbers of co-occurring endemic and non-endemic species. This process also produces an apparent positive correlation between total species number and the percentage of endemics.  相似文献   

12.
赖小红  王海洋  钟雨航  林立  李名扬 《生态学报》2019,39(21):8058-8067
叶功能性状能反映植物对环境变化的适应策略,利用开顶式熏气法,对9种常见园林植物进行为期20天的NO2熏气实验,分析不同NO2浓度熏气下叶片形态结构指标(单叶干重、单叶面积、比叶面积)、光合生理指标(光合速率、荧光参数)及化学性状指标(叶N含量、叶P含量、N:P比值)的差异,从而探讨以上植物叶性状对NO2污染的短期响应。结果表明,不同植物叶性状对不同浓度NO2污染的响应存在显著差异,即不同植物应对NO2污染的适应策略不同,同种植物在不同浓度NO2熏气下叶性状指标变化趋势相同,但变化幅度不同,可见同种植物对不同NO2浓度的响应策略也存在差异;大部分叶性状指标间表现出显著的相关性,但叶N含量与比叶面积间未发现显著相关性,表明叶经济谱性状间权衡机制的稳定性在个体尺度上可能会发生改变。研究结果揭示了不同植物对NO2污染的适应与响应差异,对预测城市NO2污染可能带来的植物功能性状的协同进化以及植物生态策略的改变具有重要意义。  相似文献   

13.
Photosynthetic capacity is one of the most sensitive parameters in vegetation models and its relationship to leaf nitrogen content links the carbon and nitrogen cycles. Process understanding for reliably predicting photosynthetic capacity is still missing. To advance this understanding we have tested across C(3) plant species the coordination hypothesis, which assumes nitrogen allocation to photosynthetic processes such that photosynthesis tends to be co-limited by ribulose-1,5-bisphosphate (RuBP) carboxylation and regeneration. The coordination hypothesis yields an analytical solution to predict photosynthetic capacity and calculate area-based leaf nitrogen content (N(a)). The resulting model linking leaf photosynthesis, stomata conductance and nitrogen investment provides testable hypotheses about the physiological regulation of these processes. Based on a dataset of 293 observations for 31 species grown under a range of environmental conditions, we confirm the coordination hypothesis: under mean environmental conditions experienced by leaves during the preceding month, RuBP carboxylation equals RuBP regeneration. We identify three key parameters for photosynthetic coordination: specific leaf area and two photosynthetic traits (k(3), which modulates N investment and is the ratio of RuBP carboxylation/oxygenation capacity (V(Cmax)) to leaf photosynthetic N content (N(pa)); and J(fac), which modulates photosynthesis for a given k(3) and is the ratio of RuBP regeneration capacity (J(max)) to V(Cmax)). With species-specific parameter values of SLA, k(3) and J(fac), our leaf photosynthesis coordination model accounts for 93% of the total variance in N(a) across species and environmental conditions. A calibration by plant functional type of k(3) and J(fac) still leads to accurate model prediction of N(a), while SLA calibration is essentially required at species level. Observed variations in k(3) and J(fac) are partly explained by environmental and phylogenetic constraints, while SLA variation is partly explained by phylogeny. These results open a new avenue for predicting photosynthetic capacity and leaf nitrogen content in vegetation models.  相似文献   

14.
The effect of leaf aging on photosynthetic capacities was examined for upper canopy leaves of five tropical tree species in a seasonally dry forest in Panama. These species varied in mean leaf longevity between 174 and 315 d, and in maximum leaf life span between 304 and 679 d. The light-saturated CO2 exchange rates of leaves produced during the primary annual leaf flush measured at 7-8 mo of age were 33-65% of the rates measured at 1-2 mo of age for species with leaf life span of < 1 yr. The negative regression slopes of photosynthetic capacity against leaf age were steeper for species with shorter maximum leaf longevity. In all species, regression slopes were less steep than the slopes predicted by assuming a linear decline toward the maximum leaf age (20-80% of the predicted decline rate). Maximum oxygen evolution rates and leaf nitrogen content declined faster with age for species with shorter leaf life spans. Statistical significance of regression slopes of oxygen evolution rates against leaf age was strongest on a leaf mass basis (r = 0.49-0.87), followed by leaf nitrogen basis (r = 0.48-0.77), and weakest on a leaf area basis (r = 0.35-0.70).  相似文献   

15.
Westoby (1998) proposed the Leaf–Height–Seed (L–H–S) scheme, i.e. the use of three functional traits, specific leaf area (SLA), plant canopy height and seed mass, to describe plant ecological strategies. In this study, we examine whether endemic species from cliffs and rocky outcrops can be discriminated in a regional Mediterranean flora according to these three traits. First, we conducted a comparison across 13 pairs of rock endemic species and widespread congeners. Second, we performed a canonical discriminant analysis to compare the position in the L–H–S volume of these 13 pairs of endemic and widespread congeners with that of 35 phylogenetically unrelated widespread species taken from the same regional flora. Our results show that rock endemic species only differ from their widespread congeners in their smaller stature. However, when compared with the 35 unrelated widespread species, endemic species are discriminated by higher SLA and taller stature, and thus are not close to the stress‐tolerant pole of ecological strategies (small stature, low SLA), as hypothesized in the literature.  相似文献   

16.
Summary The relationships between resource availability, plant succession, and species' life history traits are often considered key to understanding variation among species and communities. Leaf lifespan is one trait important in this regard. We observed that leaf lifespan varies 30-fold among 23 species from natural and disturbed communities within a 1-km radius in the northern Amazon basin, near San Carlos de Rio Negro, Venezuela. Moreover, leaf lifespan was highly correlated with a number of important leaf structural and functional characterisues. Stomatal conductance to water vapor (g) and both mass and area-based net photosynthesis decreased with increasing leaf lifespan (r2=0.74, 0.91 and 0.75, respectively). Specific leaf area (SLA) also decreased with increasing leaf lifespan (r2=0.78), while leaf toughness increased (r2=0.62). Correlations between leaf lifespan and leaf nitrogen and phosphorus concentrations were moderate on a weight basis and not significant on an area basis. On an absolute basis, changes in SLA, net photosynthesis and leaf chemistry were large as leaf lifespan varied from 1.5 to 12 months, but such changes were small as leaf lifespan increased from 1 to 5 years. Mass-based net photosynthesis (A/mass) was highly correlated with SLA (r2=0.90) and mass-based leaf nitrogen (N/mass) (r2=0.85), but area-based net photosynthesis (A/area) was not well correlated with any index of leaf structure or chemistry including N/area. Overall, these results indicate that species allocate resources towards a high photosynthetic assimilation rate for a brief time, or provide resistant physical structure that results in a lower rate of carbon assimilation over a longer time, but not both.  相似文献   

17.
Abstract: Plant species vary widely in their average leaf lifespan (LL) and specific leaf area (SLA, leaf area per dry mass). The negative LL–SLA relationship commonly seen among species represents an important evolutionary trade‐off, with higher SLA indicating greater potential for fast growth (higher rate of return on a given investment), but longer LL indicating a longer duration of the revenue stream from that investment. We investigated how these leaf‐economic traits related to aggregate properties of the plant crown. Across 14 Australian sclerophyll shrub species, those with long LL accumulated more leaf mass and leaf area per unit ground area. Light attenuation through their canopies was more severe. Leaf accumulation and light attenuation were more weakly related to SLA than to LL. The greater accumulation of foliage in species with longer LL and lower SLA may counterbalance their generally lower photosynthetic rates and light‐capture areas per gram of leaf.  相似文献   

18.
韦兰英  上官周平   《生态学报》2008,28(6):2526-2526~2535
对黄土高原不同退耕年限坡地植物比叶面积(SLA)和养分含量进行研究,探明其随生境条件而发生的变异及其与土壤理化特性之间的关系.结果表明,立地和物种水平植物SLA存在显著差异,SLA变化范围各不相同,植物叶片C、N和P含量以及C/N 、N/P和C/P在不同退耕年限坡地间不具有一致性的变化,这表明不同物种叶性因子随生境发生的变化较为复杂.草地植物叶片SLA和叶片C含量为负相关,与N、P含量呈极显著的正相关(P<0.01).土壤理化特性对叶片SLA和养分含量的关系因物种而异,综合所有植物进行分析,土壤理化特性与植物SLA的相关性不明显,但与叶片养分含量关系密切.所以,生境条件的差异可能是植物叶片结构特性和养分组成发生变化的重要原因,但调控植物叶性特征的因素较为复杂,不同的植物具有各自相应的对生境条件的适应机制.  相似文献   

19.
Tsialtas  J.T.  Pritsa  T.S.  Veresoglou  D.S. 《Photosynthetica》2004,42(3):371-376
We related leaf physiological traits of four grassland species (Poa pratensis, Lolium perenne, Festuca valida, and Taraxacum officinale), dominant in a Mediterranean grassland, to their origin and success at community level. From early May to mid-June 1999, four leaf samplings were done. Species originating from poor environments (P. pratensis, F. valida) had low carbon isotope discrimination (), specific leaf area (SLA), leaf water and mineral contents, and net photosynthetic rate on mass basis (P mass) but high chlorophyll content. The reverse traits were evident for the fast-growing species (L. perenne, T. officinale). Under the resource-limiting conditions (soil nitrogen and water) of the Mediterranean grassland, the physiological traits of P. pratensis and F. valida showed to be more adapted to these conditions leading to high species abundance and dominance.  相似文献   

20.
青海省沙珠玉治沙站17种主要植物叶性因子的比较   总被引:20,自引:2,他引:18  
国外大量研究结果表明,具有高叶氮含量和低比叶面积的干旱地区植物往往具有较高的水分利用效率。选取青海省沙珠玉治沙站地区17种主要植物(野生9种,人工8种) ,分别测定其比叶面积(SL A) ,单位重量叶氮含量(Nmass)及单位面积叶氮含量(Narea) ,并与贡嘎山湿润森林样带测定数据进行比较分析。结果表明,Nmass随SL A的增加而增加,但Nmass与SL A关系格局在固定沙丘野生多年生草本-灌木植物(类群1,Narea>3.0 g m- 2 )与流动沙丘野生短命草本植物(类群2 ,Narea<3.0 g m- 2 )之间存在策略位移现象,即在相同SL A下,类群1比类群2具有更高的叶氮含量,或在相同Nmass时类群1比类群2具有更小的比叶面积。在8个人工物种中,柠条锦鸡儿、中间锦鸡儿、绵柳和西北沙柳等灌木属于类群1,而甘草、小叶锦鸡儿、柽柳和青杨属于类群2 ,前者比后者具备更好的干旱适应机制,建议在生产上优先考虑前者。流动沙丘野生短命草本植物具有较低的叶氮含量和较高的比叶面积,这一特征与流动沙丘土壤贫瘠及其生长期内降水集中和土壤水分含量相对丰富密切相关。  相似文献   

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