山西植物功能型划分及其空间格局

随着全球气候变化的加剧,作为沟通陆地生态系统与气候变化的桥梁,植物功能型(Plant Functional Types,PFTs)越来越受到生态学家的关注。PFTs不仅是简化生态系统复杂性的有效工具,而且可将植物的生理生态过程、生物物理特征及物候变化等引入到动态植被模型中,研究气候变化下的植被反应及其反馈机制。为了在区域尺度上研究气候变化和植被反应,基于"生态-外貌"原则,依据植物特征(如生长型、叶的性状)及其对水分、温度的需求,结合区域的气候与地理条件,对山西植被进行植物功能型的划分,并在此基础上对其空间格局进行分析。结果表明:(1)山西植被可划分为19类植物功能型(其中包括4类栽培作物功能型),分别是:寒温性常绿针叶林、温性常绿针叶林、寒温性落叶针叶林、温性落叶阔叶林、高寒落叶灌丛、温性落叶灌丛、多年生禾草草原、多年生禾草草丛、多年生禾草草甸、多年生莎草草甸、多年生杂类草草原、多年生杂类草草丛、多年生杂类草草甸。1年生杂类草草甸、多年生豆科草原、果树、一年一熟栽培作物、一年二熟栽培作物和二年三熟栽培作物。植物功能型的划分和分布与山西植被区划有较好的一致性,基本反映了植物固有特征及其对水热条件的需求。(2)农作物在山西占有较大比重,占植被类型面积的53.15%,森林类型以温性常绿针叶林和温性落叶阔叶林为主,灌丛类型以温性落叶灌丛为主,草本类型中多年生禾草草丛占较大比例,占草本类型面积的50.98%。(3)由于水热条件及地理条件的差异,植物功能型(不考虑栽培作物)在各区域表现出较大差异,如多年生杂类草草原主要分布于北部地区,在南部并不存在这种植物功能型;森林类型的功能型主要分布于中、南部地区,且结构复杂、类型多样。(4)除栽培作物表现出较好的整体性和连通性,其他植物功能型均表现出不同程度的破碎化和离散化。(5)山西植物功能型整体上表现出较高的多样性,其中中部地区比其他地区的多样性和破碎化程度高,斑块类型更加趋向于离散的小斑块状,北部地区则以一年一熟栽培作物占明显优势,表现出较强的优势度,而南部地区并没有表现出很强的破碎度或优势度。     

Response of photosynthesis of different plant functional types to environmental changes along Northeast China Transect

Net photosynthesis (P_n), transpiration (E), stomatal conductance (g_s), internal CO₂ concentration (C_i), and water use efficiency (WUE) were examined on 215 species from eight plant functional types (PFTs) along a precipitation gradient in northeast China (the Northeast China Transect, or NECT). Among the eight PFTs, meadow steppe grasses had the highest rates of net photosynthesis and forest grasses the lowest and the following order of P_n was noted: meadow steppe grasses >typical steppe grasses >steppe shrubs >desert grasses >forest trees >forest shrubs >desert shrubs >forest grasses (P<0.05). Transpiration tended to be the highest in the steppe grasses and lowest in forest shrubs. Transpiration also decreased rapidly with the appearance of C₃ desert species at the desert end. The forest tree PFT had lower P_n, E, g_s than the steppe PFTs, whereas WUE values were somewhat greater in the forest tree PFT than the desert shrubs and grasses. Low C_i values along the steppe section (from 400 to 1100 km, east to west) indicated the presence of C₄ species. Of all the PFTs, only shrubs and herbs were noted at all points along the transect. No clear relationship between P_n, E, g_s, WUE of herb and shrub PFTs and annual precipitation was noted – low values were found at both the high and low precipitation ends of the transect. Highest values were noted when precipitation was intermediate. Received: 28 October 1998 / Accepted: 10 May 1999     

Plant functional types and ecosystem function in relation to global change

Abstract. Plant functional types (PFTs) bridge the gap between plant physiology and community and ecosystem processes, thus providing a powerful tool in climate change research. We aimed at identifying PFTs within the flora of central-western Argentina, and to explore their possible consequences for ecosystem function. We analyzed 24 vegetative and regenerative traits of the 100 most abundant species along a steep climatic gradient. Based on plant traits and standard multivariate techniques, we identified eight PFTs. Our results confirmed, over a wide range of climatic conditions, the occurrence of broad recurrent patterns of association among plant traits reported for other floras; namely trade-offs between high investment in photosynthesis and growth on the one hand, and preferential allocation to storage and defence on the other. Regenerative traits were only partially coupled with vegetative traits. Using easily-measured plant traits and individual species cover in 63 sites, we predicted main community-ecosystem processes along the regional gradient. We hypothesized likely impacts of global climatic change on PFTs and ecosystems in situ, and analysed their probabilities of migrating in response to changing climatic conditions. Finally, we discuss the advantages and limitations of this kind of approach in predicting changes in plant distribution and in ecosystem processes over the next century.     

An improved method for searching plant functional types by numerical analysis

Abstract. The use of plant functional types (PFTs) to describe patterns and processes in plant communities has become essential to study and predict consequences of global change on vegetation and ecosystem processes. A PFT is a group of plants that, irrespective of phylogeny, are similar in a given set of traits and similar in their association to certain variables, which may be factors to which the plants are responding or effects of the plants in the ecosystem. To define PFTs relevant traits must be selected and an appropriate method must be used to classify plants into types. We critically review methods used for the analysis of PFT‐based data and describe a new recursive algorithm to numerically search for traits and find optimal PFTs. The algorithm uses three data matrices: describing populations by traits, communities by these populations and community sites by environmental factors or effects. It defines PFTs polythetically by cluster analysis, revealing plant types whose performance in communities is maximally associated to the specified environmental variables. We test the method with data from natural grassland communities of southern Brazil, which were experimentally subjected to combinations of grazing levels and N‐fertilizer. The new method is found to be better than similar analytical procedures previously described. Redundancy among traits is discussed and a procedure for comparing alternative solutions is presented based on the similarity in terms of PFT responses between different trait subsets. The concept of PFT response group is illustrated by example.     

Priority Effects of Time of Arrival of Plant Functional Groups Override Sowing Interval or Density Effects: A Grassland Experiment

Priority effects occur when species that arrive first in a habitat significantly affect the establishment, growth, or reproduction of species arriving later and thus affect functioning of communities. However, we know little about how the timing of arrival of functionally different species may alter structure and function during assembly. Even less is known about how plant density might interact with initial assembly. In a greenhouse experiment legumes, grasses or forbs were sown a number of weeks before the other two plant functional types were sown (PFT) in combination with a sowing density treatment. Legumes, grasses or non-legume forbs were sown first at three different density levels followed by sowing of the remaining PFTs after three or six-weeks. We found that the order of arrival of different plant functional types had a much stronger influence on aboveground productivity than sowing density or interval between the sowing events. The sowing of legumes before the other PFTs produced the highest aboveground biomass. The larger sowing interval led to higher asymmetric competition, with highest dominance of the PFT sown first. It seems that legumes were better able to get a head-start and be productive before the later groups arrived, but that their traits allowed for better subsequent establishment of non-legume PFTs. Our study indicates that the manipulation of the order of arrival can create priority effects which favour functional groups of plants differently and thus induce different assembly routes and affect community composition and functioning.     

黄土丘陵区植物叶片与细根功能性状关系及其变化

通过植物叶片功能性状(比叶面积、叶组织密度、叶氮含量)和细根功能性状(比根长、根组织密度、根氮含量)间的相互关系,分析植物对环境的适应途径;然后根据性状间的差异进行了层次聚类,将物种划分为3大功能型,并分析了不同功能型对环境的适应策略.结果表明:黄土丘陵区延河流域149种植物的叶氮含量与比叶面积和根氮含量正相关、与叶组织密度负相关,比根长与根组织密度负相关,除了根氮含量,其余根性状与叶性状不相关.此外,功能性状间关系变化和适应策略在不同功能型之间也存在差异.功能型1的植物具有最强的耐旱力和防御力;功能型3的植物具有最强的养分维持能力用以对抗营养贫瘠的环境;功能型2的植物居中,生长速率最高,具有较强的竞争力、分布最广;根据C-S-R理论,功能型1和3属于“胁迫忍耐型”策略(S策略),功能型2则属于“竞争型”(C)和“干扰型”(R)策略的综合.研究结果为黄土丘陵区植被恢复规划及物种配置等提供依据.     

Photosynthetic and morphological functional types for native species from mixed prairie in Southern Saskatchewan, Canada

Photosynthetic pathways (e.g. C₃, C₄) and morphological functional types (e.g. trees, shrubs, high perennial grasses, perennial forbs) were identified for the native species from the Saskatchewan mixed prairie, using the data from references published between 1950 and 2003. Of the total 219 identified species in 145 genera and 45 families, 208 species in 137 genera and 44 families were found with C₃ photosynthesis, and most of these species are dominants (e.g. Agropyron dasystachyum Hook. and Stipa spartea var. curtiseta Hitchc.). 11 species in 10 genera and 3 families were identified with C₄ photosynthesis (e.g. Atriplex argentea Nutt., Andropogon scoparius Michx., Boutelou gracilis Lag., Calamovilfa longifolia Hook.). The amount of total identified C₄ species in the region is much less than that from the South Dakota mixed prairie (27 species). Gramineae is the leading family with C₄ photosynthesis (8 species), Chenopodiaceae ranks the second (2 species). Relatively less forb types [50 % perennial forbs (PEF) and 12 % annual forbs (ANF)] and more graminoid types (25 %) composition suggested that the rangelands in the region are relatively stable. Lacking of the knowledge on the optimal traits for PFTs classification in the region, further studies (e.g. C₃ and C₄ plant identification and optimal trait selection) are needed to explore the relationships between PFTs and vegetation variations, as well as land-use and climate changes.     

Are There Consistent Grazing Indicators in Drylands? Testing Plant Functional Types of Various Complexity in South Africa’s Grassland and Savanna Biomes

Despite our growing knowledge on plants’ functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa’s grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be useful for identifying ecological indicators in other ecosystems.     

Sensitivity of plant functional types to climate change: classification tree analysis of a simulation model

Question: The majority of studies investigating the impact of climate change on local plant communities ignores changes in regional processes, such as immigration from the regional seed pool. Here we explore: (i) the potential impact of climate change on composition of the regional seed pool, (ii) the influence of changes in climate and in the regional seed pool on local community structure, and (iii) the combinations of life history traits, i.e. plant functional types (PFTs), that are most affected by environmental changes. Location: Fire‐prone, Mediterranean‐type shrublands in southwestern Australia. Methods: Spatially explicit simulation experiments were conducted at the population level under different rainfall and fire regime scenarios to determine the effect of environmental change on the regional seed pool for 38 PFTs. The effects of environmental and seed immigration changes on local community dynamics were then derived from community‐level experiments. Classification tree analyses were used to investigate PFT‐specific vulnerabilities to climate change. Results: The classification tree analyses revealed that responses of PFTs to climate change are determined by specific trait characteristics. PFT‐specific seed production and community patterns responded in a complex manner to climate change. For example, an increase in annual rainfall caused an increase in numbers of dispersed seeds for some PFTs, but decreased PFT diversity in the community. Conversely, a simulated decrease in rainfall reduced the number of dispersed seeds and diversity of PFTs. Conclusions: PFT interactions and regional processes must be considered when assessing how local community structure will be affected by environmental change.     

Ecophysiological and bioclimatic foundations for a global plant functional classification

Question: What plant properties might define plant functional types (PFTs) for the analysis of global vegetation responses to climate change, and what aspects of the physical environment might be expected to predict the distributions of PFTs? Methods: We review principles to explain the distribution of key plant traits as a function of bioclimatic variables. We focus on those whole‐plant and leaf traits that are commonly used to define biomes and PFTs in global maps and models. Results: Raunkiær's plant life forms (underlying most later classifications) describe different adaptive strategies for surviving low temperature or drought, while satisfying requirements for reproduction and growth. Simple conceptual models and published observations are used to quantify the adaptive significance of leaf size for temperature regulation, leaf consistency for maintaining transpiration under drought, and phenology for the optimization of annual carbon balance. A new compilation of experimental data supports the functional definition of tropical, warm‐temperate, temperate and boreal phanerophytes based on mechanisms for withstanding low temperature extremes. Chilling requirements are less well quantified, but are a necessary adjunct to cold tolerance. Functional traits generally confer both advantages and restrictions; the existence of trade‐offs contributes to the diversity of plants along bioclimatic gradients. Conclusions: Quantitative analysis of plant trait distributions against bioclimatic variables is becoming possible; this opens up new opportunities for PFT classification. A PFT classification based on bioclimatic responses will need to be enhanced by information on traits related to competition, successional dynamics and disturbance.     

Photosynthetic and morphological functional types from different steppe communities in Inner Mongolia,North China

Morphological functional types and photosynthetic pathway types were identified for the forage species from steppe communities in Inner Mongolia, China, using the data of both field survey and published papers. Seven typical steppe communities were selected to investigate the morphological functional type and photosynthetic pathway type compositions and plant functional type (PFT) diversity in steppe communities at regional scale. Morphological functional types, based on plant height and leaf type combined with life span, were optimal for comparing the community differences in the region, while photosynthetic pathway types were fairly coarse for such studies. Of the seven morphological functional types in the steppe communities, perennial forbs (PEF) were the dominant type, and 60 % of species belonged to this type. Each of the high perennial grass (HPG), short perennial grass (SPG), and annual grass (ANG) types represented less than 10 % of the total, even though the grass species were dominant in the seven steppe communities. The differences of PFTs between the steppe communities were remarkable, and the PFT richness and diversity increased from the communities with moist conditions to the ones with dry environments.     

Endemic species and ecosystem sensitivity to climate change in Namibia

We present a first assessment of the potential impacts of anthropogenic climate change on the endemic flora of Namibia, and on its vegetation structure and function, for a projected climate in ～2050 and ～2080. We used both niche‐based models (NBM) to evaluate the sensitivity of 159 endemic species to climate change (of an original 1020 plant species modeled) and a dynamic global vegetation model (DGVM) to assess the impacts of climate change on vegetation structure and ecosystem functioning. Endemic species modeled by NBM are moderately sensitive to projected climate change. Fewer than 5% are predicted to experience complete range loss by 2080, although more than 47% of the species are expected to be vulnerable (range reduction >30%) by 2080 if they are assumed unable to migrate. Disaggregation of results by life‐form showed distinct patterns. Endemic species of perennial herb, geophyte and tree life‐formsare predicted to be negatively impacted in Namibia, whereas annual herb and succulent endemic species remain relatively stable by 2050 and 2080. Endemic annual herb species are even predicted to extend their range north‐eastward into the tree and shrub savanna with migration, and tolerance of novel substrates. The current protected area network is predicted to meet its mandate by protecting most of the current endemicity in Namibia into the future. Vegetation simulated by DGVM is projected to experience a reduction in cover, net primary productivity and leaf area index throughout much of the country by 2050, with important implications for the faunal component of Namibia's ecosystems, and the agricultural sector. The plant functional type (PFT) composition of the major biomes may be substantially affected by climate change and rising atmospheric CO₂– currently widespread deciduous broad leaved trees and C₄ PFTs decline, with the C₄ PFT particularly negatively affected by rising atmospheric CO₂ impacts by ～2080 and deciduous broad leaved trees more likely directly impacted by drying and warming. The C₃ PFT may increase in prominence in the northwestern quadrant of the country by ～2080 as CO₂ concentrations increase. These results suggest that substantial changes in species diversity, vegetation structure and ecosystem functioning can be expected in Namibia with anticipated climate change, although endemic plant richness may persist in the topographically diverse central escarpment region.     

沿中国东北样带 (NECT)分布的若干克隆植物与非克隆植物光合速率与水分利用效率的比较(英文)

比较了沿 1 6 70km长的中国东北样带 (NECT)分布的在繁殖习性上不同的植物功能型 ,克隆植物 (clonalplant)与非克隆植物 (non_clonalplant)的光合作用、蒸腾作用、气孔导度、水分利用效率。所测定的 2 1 8种植物中有1 1 5种属于克隆植物。对于灌木和草本植物功能型而言 ,净光合速率 (Pn)和水分利用效率 (WUE)在样带东西两端较低 ,在样带中间较高 ;蒸腾速率在温带荒漠植物分布的西端出现升高的趋势。在森林乔木、森林灌木、森林草本、草甸草原灌木、草甸草原草本、典型草原灌木、典型草原草本、荒漠草原灌木、荒漠草原草本等不同功能型的植物中 ,典型草原灌木和草本植物的光合生理指标较高。在相同的生长环境中 ,克隆植物比非克隆植物表现出较高的Pn 以及其他生理指标。克隆植物的光合速率、蒸腾速率、气孔导度、水分利用效率分别比非克隆植物高出 2 2 %、1 5 %、2 3%和 1 4 %。这种现象表明克隆植物在CO2 、光能和水分资源利用能力上优于非克隆植物     

Photosynthetic and morphological functional types from different steppe communities in Inner Mongolia, North China

Morphological functional types and photosynthetic pathway types were identified for the forage species from steppe communities in Inner Mongolia, China, using the data of both field survey and published papers. Seven typical steppe communities were selected to investigate the morphological functional type and photosynthetic pathway type compositions and plant functional type (PFT) diversity in steppe communities at regional scale. Morphological functional types, based on plant height and leaf type combined with life span, were optimal for comparing the community differences in the region, while photosynthetic pathway types were fairly coarse for such studies. Of the seven morphological functional types in the steppe communities, perennial forbs (PEF) were the dominant type, and 60 % of species belonged to this type. Each of the high perennial grass (HPG), short perennial grass (SPG), and annual grass (ANG) types represented less than 10 % of the total, even though the grass species were dominant in the seven steppe communities. The differences of PFTs between the steppe communities were remarkable, and the PFT richness and diversity increased from the communities with moist conditions to the ones with dry environments.This revised version was published online in March 2005 with corrections to the page numbers.     

Divergence of functional traits at early stages of development in Stipa tenacissima populations distributed along an environmental gradient of the Mediterranean

Assessing differences in plant functional traits (PFTs) along climatic gradients is potentially useful for understanding variation within and across populations, and for predicting their responses to climate change. This study investigates the intraspecific variability of several PFTs in Stipa tenacissima (Alpha grass) seedlings from different populations distributed across a climatic gradient. Seven populations from Tunisia to Spain within a 100–600 mm/year rainfall range were selected. Seedlings from each population were grown in a common garden. We expected the functional characteristics to differ among seedling populations according to their climatic gradient. The response patterns were helpful to predict acclimation and fitness under future climatic conditions in these populations. The seedling development analysis showed differences in PFTs among S. tenacissima populations. The biomass traits analysis revealed that higher above-ground biomass was related to higher below-ground development. The leaf traits proved that seedlings with longer leaf length would have less sclerophyllous leaves, a trade-off between productivity and drought resistance. The root traits analysis reflects seedling strategies to maximize resource uptake efficiency. PFTs showed several significant relationships with climatic conditions. The less rainfall, the higher plant allocation to root systems exploring soil. Higher mean temperatures were related to reduced root/plant development. The PFT analysis proves that species followed the ‘optimal partitioning theory’, in that plants preferentially allocate biomass to acquire the resource that most limits their development. However, both the environmental conditions and genetic diversity in S. tenacissima populations influenced seedling growth and behaviour to face ongoing climate change.

     

A Comparative Study on Photosynthesis and Water Use Efficiency Between Clonal and Non-clonal Plant Species Along the Northeast China Transect (NECT)

Net photosynthesis (P n), transpiration (E), stomatal conductance (g s) and water use efficiency (WUE) of more than 218 species belonging to two different reproductive functional types, i.e. clonal (115 species) and non-clonal species (103 species), along the 1 670 km Northeast China Transect (NECT) were analyzed. The results showed that P n and WUE appeared to be lower in the east and west ends of NECT, with peaks in the middle. Transpiration was found to be higher in the west end, where most temperate desert species were distributed. On the same site, most clonal species showed higher P n and related physiological variables than non-clonal species. For different growth forms over NECT, e.g. forest trees, shrubs and grasses, meadow steppe shrubs and grasses, typical steppe shrubs and grasses, the meadow steppe and typical steppe grasses, showed higher values of physiological variables than the forest or the desert species. But for the two reproductive plant functional types (PFTs), clonal species had higher physiological variables, with averages of 22%, 15%, 23% and 14% higher than the non-clonal ones for P n, E, gs, and WUE, respectively. Such differences indicated that clonal species might have advantages over non-clonal species in utilizing environmental resources such as light, CO2, and especially water.     

Plant functional traits with particular reference to tropical deciduous forests: a review

Functional traits (FTs) integrate the ecological and evolutionary history of a species, and can potentially be used to predict its response as well as its influence on ecosystem functioning. Study of inter-specific variation in the FTs of plants aids in classifying species into plant functional types (PFTs) and provides insights into fundamental patterns and trade-offs in plant form and functioning and the effect of changing species composition on ecosystem functions. Specifically, this paper focuses on those FTs that make a species successful in the dry tropical environment. Following a brief overview, we discuss plant FTs that may be particularly relevant to tropical deciduous forests (TDFs). We consider the traits under the following categories: leaf traits, stem and root traits, reproductive traits, and traits particularly relevant to water availability. We compile quantitative information on functional traits of dry tropical forest species. We also discuss trait-based grouping of plants into PFTs. We recognize that there is incomplete knowledge about many FTs and their effects on TDFs and point out the need for further research on PFTs of TDF species, which can enable prediction of the dynamics of these forests in the face of disturbance and global climate change. Correlations between structural and ecophysiological traits and ecosystem functioning should also be established which could make it possible to generate predictions of changes in ecosystem services from changes in functional composition.     

用于全球变化研究的中国植物功能型划分

 植物功能型(Plant functional types, PFTs)作为沟通植物的结构和功能与生态系统属性的桥梁,随着全球变化与植被的关系研究的深入而受到广泛重视。植物功能型的划分依赖于研究的背景、尺度和要解决的问题。为了区域尺度全球变化研究的需要,该文提出了一个基于植物关键特征的植物功能型划分方法。该方法首先选择了6项植物特征,包括3项冠层特征：木本-草本、常绿-落叶和针叶-阔叶,以及3项生理特征：光合途径(C3 / C4)、植物的水分需求和热量需求,作为划分植物功能型的关键特征;然后,先根据植物冠层特征划分得到5个基本类型,再根据水分和热量条件进行详细划分,得到29种备选类型;需要时,再根据研究目的从这29种备选类型中选择所需类型。根据这个方法,在充分考虑了我国季风气候条件下特有的水热配置和高海拔环境对植物的形态和功能特征影响的基础上,从备选类型中选择了一套适合中国气候和植被特征的植物功能型体系。这套体系包括18类植物功能型,其中含7类‘树’功能型、6类‘灌木’功能型和5类‘草’功能型,另根据需要设置2类‘裸地’功能型。并且根据植物的生理生态特征和中国植被的地理分布确定了用于限制植物功能型分布的气候因子,这些气候因子包括绝对最低温度、最暖月平均温度、有效积温、年最热月平均温和最冷月平均温之差、湿润指数、年均降水量。应用表明,这套植物功能型可用于模拟我国植被在当前气候条件下的分布。该研究为发展适于我国的植被模型和区域气候模型、评估全球变化对我国植被的影响及植被变化对气候的反馈作用提供依据与参数。     

Variation in plant diversity and dominance across dune fixation stages in the Chinese steppe zone

Aims Our aim was to study how diversity and dominance of plant species and plant functional types (PFTs) change and covary across three dune fixation stages in the Chinese steppe zone.Methods In the Chinese steppe zone, we measured coverage, mean height and density of each plant species in three types of dunes (mobile, semi-fixed and fixed dunes) in four sites (Mu Us, Otindag, Hulunbeir and Horqin). Plant species were grouped into 24 PFTs according to their lifespan, photosynthetic pathway, reproductive mode and life form. Dominance of each plant species and PFT were determined, and species diversity and PFT diversity were quantified using Shannon–Wiener index.Important findings PFT diversity was positively related to plant species diversity in each dune stage, but PFT diversity increased more with increasing plant species diversity in the mobile and semi-fixed dunes than in the fixed dunes. Dune fixation stage explained 87.2% of the variation in plant species diversity and 84.8% of the variation in PFT diversity. Dominant species and PFTs differed among the three dune fixation stages; the more fixed the dunes were, the more perennial, shrubby, clonal and C₃ species co-dominated. Specifically, in mobile dunes annual C₄ non-clonal herbs were the most dominant, and in semi-fixed and fixed dunes perennial C₃ clonal shrubs were most dominant.