Distribution of bulbil- and seed-producing plants of Poa alpina (Poaceae) and their growth and reproduction in common gardens suggest adaptation to different elevations

• Premise of the study: The European Alps harbor a spatially heterogeneous environment. Plants can be adapted genetically to this heterogeneity but may also respond to it by phenotypic plasticity. We expected the important fodder grass Poa alpina to be adapted to elevation either genetically or plastically. • Methods: We investigated in three elevational common gardens whether growth and reproductive allocation of plants reproducing either by seeds or bulbils suggest adaptation to their elevation of origin and to what extent they can respond plastically to different elevations. Additionally, we analyzed genetic diversity using microsatellites and tested whether seeds are of sexual origin. • Key results: In the field, bulbil-producing plants occurred more often at higher elevations, whereas seed-producing plants occurred more often at lower elevations, but bulbil-producing plants were generally less vigorous in the common gardens. The response of plants to elevational transplantation was highly plastic, and vigor was always best at the highest location. The small genetic differences were not clinally related to elevation of origin, underlining the importance of phenotypic plasticity. Reproductive allocation was, however, independent of elevational treatments. Seed-producing plants had higher genetic diversity than the bulbil-producing plants even though we found that seed-producing plants were facultative apomicts mostly reproducing asexually. • Conclusions: Bulbil-producing P. alpina, showing a fitness cost at lower elevations compared with seed-producing plants, seem better adapted to higher elevations. By means of its two reproductive modes and the capacity to adjust plastically, P. alpina is able to occupy a broad ecological niche across a large elevational range.     

Soil temperature drives elevational patterns of reproductive allometry in a biodiversity hotspot

Understanding the geographic patterns of reproductive allocation helps in clarifying the selective forces that shape the reproductive strategies of plants. However, studies on the elevational patterns of reproductive allocation remain limited. Moreover, although soil attributes have long been suspected to drive elevational patterns of reproductive allocation, few studies have explored this relationship. Delaying reproduction and allocating a high proportion of biomass to vegetative organs may be risky for plants living under high-elevation habitats, as these two processes can potentially lead to plant reproductive failure due to the low temperatures and short growing seasons at high elevations. Thus, we hypothesize that reproductive effort will increase with elevation and the elevational pattern of reproductive allocation will be largely driven by soil attributes, given their covariation with elevation. To test these hypotheses, we determined the vegetative and reproductive biomass of individual Impatiens arguta (Balsaminaceae) plants across 12 populations in the Gaoligong Mountains (China), and collected data on soil temperature, nutrients, moisture, and pH for each population. Based on standard major axis regression and linear regression models, we found that (1) both vegetative and reproductive biomass decreased with elevation; (2) all populations demonstrated significant allometric slopes (i.e., linear coefficients of log[reproductive biomass]???log[vegetative biomass] regressions)?>?1; (3) allometric slopes decreased with elevation; and (4) soil temperature was a better predictor of the allometric slope than elevation, i.e., the allometric slope decreased with soil temperature. These results suggest that plant species growing at high elevation invest proportionately more resources to reproduction as an adaptation to low-temperature environments, and reproductive output is heavily dependent on vegetative growth. This study provides the first evidence of soil temperature driving reproductive allocation patterns, which suggests that plant species will favor allocation to growth under increasing soil temperatures with climate warming.

     

川西风毛菊果期资源分配对海拔的响应

以分布于青藏高原东缘的川西风毛菊为试验材料,研究了其不同海拔高度16个居群的果期资源分配。结果显示:1)随着海拔的升高,个体大小、繁殖器官生物量、营养器官生物量、根系质量、茎叶质量以及每株植物种子总数量均不断减小,但种子百粒重不断增加;2)繁殖分配和根系分配与海拔呈正相关关系,营养分配和茎叶分配与海拔呈负相关关系;3)果期繁殖分配和营养分配、根系分配和茎叶分配以及种子数量与百粒重之间均存在资源分配上的权衡。研究结论:1)海拔作为外界因子对川西风毛菊果期各生物量及资源分配有显著的影响;2)随着海拔的升高,川西风毛菊通过增加繁殖分配,根系分配以及种子百粒重来适应胁迫环境,提高自身的适合度。     

No effect of elevation and fragmentation on genetic diversity and structure in Polylepis australis trees from central Argentina

Phenological differences in flowering arising along elevational gradients may be caused by either local adaptation or phenotypic plasticity. Local adaptation can lead to reproductive isolation of populations at different elevational zones and thus produce elevational genetic structuring, while phenotypic plasticity does not produce elevational genetic structuring. In this study, we examined the effects of elevation and fragmentation on genetic diversity and structure of Polylepis australis populations, where individuals exhibit phenological differences in flowering along an elevational gradient. We assessed the polymorphism of amplified fragment length polymorphism markers in adults and saplings from one conserved and one fragmented forest covering elevations from 1600 to 2600 m asl. Over 98% of variation was found within populations, and we found very low and similar genetic differentiation along elevational gradients for adults and saplings in both continuous and fragmented forests. In addition, there was no significant relationship between genetic diversity and elevation. Results indicated that phenological differences along elevational gradients are more likely caused by phenotypic plasticity than local adaptation, and fragmentation does not appear to have affected genetic diversity and differentiation in the studied populations. Results therefore imply that if necessary, seeds for reforestation purposes may be collected from different elevations to the seeding or planting sites.     

Interactions in the patterns of vegetative growth and reproduction in woody dioecious plants

Summary Interactions between vegetative growth and reproduction were evaluated in Peumus boldus, Lithraea caustica and Laretia acaulis, three woody dioecious species in central Chile. Phenological observations were made periodically on marked branches of male and female plants, and biomass allocation (dry weight) to vegetative and reproductive tissues was measured. The magnitude of flowering was evaluated in groups of plants in three successive seasons. The patterns of activities are species- and sex-dependent, and cycles of 2–4 years have been established. Branches that produce flowers either do not grow or grow less than branches without flowers, and males and females have differential resource allocation: male branches attain higher biomass values. Groups of plants show seasonal behavior that suggest synchrony in their reproductive activities.     

Ecophysiology and genetic diversity in species of the bamboo Chusquea in the high Andes,Venezuela

ABSTRACT

Background: Woody bamboos of the genus Chusquea grow along a broad range of elevations in the Venezuelan Andes. Their growth-form and density vary along the cloud forest – páramo gradient. In this article, we related ecophysiological traits and population genetic diversity information to explain the distribution of growth-form patterns of Chusquea in the Merida Andes, Venezuela.

Aims: We quantified differences in the ecophysiological response and genetic diversity of scandent cloud forest and shrub-like páramo bamboos of the genus Chusquea, taking in account the differences in their flowering patterns, growth-form and habitat.

Methods: We related low temperature resistance, water relations and leaf gas exchange variables to the growth-form, habitat, flowering patterns and genetic diversity in species of Chusquea. The genetic diversity study was based on Inter Sequence Simple Repeats and Random Amplified Polymorphic DNA markers analysis of cloud forest and páramo populations.

Results: Scandent cloud forest and shrub-like páramo species of Chusquea had a very similar ecophysiological response for all the variables analysed during wet and dry seasons and were capable of enduring freezing temperatures through moderate supercooling. Species associated with the cloud forest – páramo gradient maintained low stomatal conductance and transpiration rates that favoured high leaf water potentials, without limiting photosynthetic rates. Shrub-like bamboos growing above the continuous forest line had a small decline in net photosynthesis rates, associated with an increase in water use efficiency. Both scandent and shrub-like bamboos had a remarkably high genetic diversity, comparable to non-clonal species.

Conclusions: Species of Chusquea in the Venezuelan Andes are a physiologically relatively homogeneous group across a broad elevation gradient. Population genetic diversity appears to be more related with their flowering pattern and habitat conditions than with their growth form.     

Flowering phenology and reproductive fitness along a mountain slope: maladaptive responses to transplantation to a warmer climate in Campanula thyrsoides

In many biomes, global warming has resulted in advanced and longer growing seasons, which has often led to earlier flowering in plant taxa. Elevational gradients are ideal to study the effects of global warming as they allow transplantation of plants from their original cooler higher elevations down to elevations with a prospective climate. We transplanted plants from ten populations of the European alpine monocarpic herb species Campanula thyrsoides L. to three sites along a steep mountain slope (600, 1,235 and 1,850 m above sea level) in the Swiss Alps and asked whether reproductive phenology adjusts plastically to elevation and if these responses were adaptive, i.e. increased the fitness of plants. We further assessed current genetic differentiation in phenotypic traits and whether any such origin effects were due to adaptation to climatic conditions of origin. Our results showed that transplantation to lower elevations caused strong shifts in phenology, with plants starting growth and flowering earlier than plants placed at higher elevations. However, compared to flower production at high elevation, number of flowers per plant decreased 21 % at mid- and 61 % at low elevation. The shift in phenology thus came with a high cost in fitness, and we suggest that phenology is maladaptive when C. thyrsoides faces temperature conditions deviating from its natural amplitude. We conclude that the frequently reported phenological shift in plant species as a response to global warming may include heavy fitness costs that may hamper species survival.     

展毛翠雀花期繁殖特征和生物量分配对放牧的响应

生物量分配影响植物生长和繁殖,是植物生活史研究的重要内容。为了了解植物生活史性状对放牧的响应,该研究以青藏高原高寒草甸毒杂草展毛翠雀为对象,分析了放牧干扰对展毛翠雀的花期繁殖分配和性分配的影响。结果表明:放牧显著降低了展毛翠雀的总生物量、个体大小和繁殖投入; 放牧未改变展毛翠雀的营养部分与繁殖部分的等速生长关系,但显著增加了繁殖部分的生物量分配和总花数; 展毛翠雀的个体大小与总花数呈显著的正相关关系,但与性分配呈显著的负相关关系; 展毛翠雀的总花数与单花大小、单花的花瓣比例均表现出负相关关系,表明总花数与单花大小之间、总花数与单花的花瓣比例之间均存在权衡。因此,在放牧条件下,展毛翠雀的繁殖分配和性分配均表现出显著的可塑性。     

Trait differentiation and adaptation of plants along elevation gradients

Studies of genetic adaptation in plant populations along elevation gradients in mountains have a long history, but there has until now been neither a synthesis of how frequently plant populations exhibit adaptation to elevation nor an evaluation of how consistent underlying trait differences across species are. We reviewed studies of adaptation along elevation gradients (i) from a meta‐analysis of phenotypic differentiation of three traits (height, biomass and phenology) from plants growing in 70 common garden experiments; (ii) by testing elevation adaptation using three fitness proxies (survival, reproductive output and biomass) from 14 reciprocal transplant experiments; (iii) by qualitatively assessing information at the molecular level, from 10 genomewide surveys and candidate gene approaches. We found that plants originating from high elevations were generally shorter and produced less biomass, but phenology did not vary consistently. We found significant evidence for elevation adaptation in terms of survival and biomass, but not for reproductive output. Variation in phenotypic and fitness responses to elevation across species was not related to life history traits or to environmental conditions. Molecular studies, which have focussed mainly on loci related to plant physiology and phenology, also provide evidence for adaptation along elevation gradients. Together, these studies indicate that genetically based trait differentiation and adaptation to elevation are widespread in plants. We conclude that a better understanding of the mechanisms underlying adaptation, not only to elevation but also to environmental change, will require more studies combining the ecological and molecular approaches.     

Genetic variation in flowering phenology and reproductive performance in a Mediterranean high‐mountain specialist,Armeria caespitosa (Plumbaginaceae)

Adaptive responses to past climate change may play an important role in the persistence of high‐mountain plants, which are vulnerable to global warming. Armeria caespitosa is a high‐mountain plant, endemic to the Iberian Central Range. Differences in abiotic environment along the elevational gradient impose two opposing stress gradients (i.e. water stress and duration of the growth season) on the species. Furthermore, the species is found in two interspersed, contrasting microhabitats (rocky outcrops and dry cryophilic grasslands) that have different effects on plants depending of the elevation. As a result of this, the species shows great among‐population variation in many reproductive and vegetative traits. We used a common garden approach to determine whether this phenotypic variation has a genetic basis or is the result of plastic responses shaped by heterogeneous environmental conditions. Plants from the high‐elevation edge and dry cryophilic grasslands flowered earlier and produced more viable fruits but were smaller. These results confirm that among‐population variation in flowering phenology and reproductive performance traits in A. caespitosa is partially genetically based. The results also show that the stronger selection response in favour of early‐flowering individuals in populations at the low‐elevation edge did not correspond with the greater proportion of early‐flowering individuals. Genetic variability associated with flowering onset may be relevant in coping with the impacts of ongoing global warming. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176 , 384–395.     

Crop presence,but not genetic diversity,impacts on the rare arable plant Valerianella rimosa

Background: Intensive farming affects farmland biodiversity, and some arable plants in particular. Increasing crop genetic diversity can increase crop productivity or resilience and could also benefit rare arable plants.

Aims: We examined whether barley presence, sowing density and genetic diversity impacted the rare plant Valerianella rimosa and explored possible underlying mechanisms.

Methods: In a field study near Dundee, Scotland, we sowed plots of five single barley genotypes, and all five genotypes combined, at three densities; we also had barley-free plots. Valerianella seeds were sown into half of all plots. Measured responses included early-season cover and harvest biomass of barley and common weeds, abiotic parameters (soil moisture, light) and establishment, biomass and seed production by V. rimosa.

Results: Barley presence promoted V. rimosa establishment early in the growing season, but without barley density or genetic diversity effects. By harvest, the impact of barley presence on V. rimosa abundance was lost; there were no effects on Valerianella seed production. Barley negatively impacted common weeds, but V. rimosa did not benefit from any indirect facilitation by barley, being bigger without barley.

Conclusions: Early beneficial effects of barley on V. rimosa abundance appear offset by late-season competition. However, limited impacts of barley on V. rimosa reproductive success, and negative impacts on common weeds, indicate crops might play a role in conservation management of rare arable plants by creating space in the weed community.     

Elevational patterns of bryophyte and lichen biomass differ among substrates in the tropical montane forest of Baru Volcano,Panama

Introduction. Tropical montane forests support a high abundance and diversity of bryophytes and lichens on different substrates. However, quantitative information about how their biomass and water-holding capacity change with elevation is scarce. The current project assessed variation in the biomass and water-holding capacity of bryophytes and lichens on Baru Volcano, Panama.

Methods. On the western slope, the bryophyte and lichen layer was collected from 600?cm² plots on six substrate types with four replications at eight elevations along a gradient from 1900 to 3300?m a.s.l. We recorded the thickness, water-holding capacity and biomass of all samples, as well as environmental parameters.

Key results. At lower elevations substrates had a similar biomass and water-holding capacity per area, but with increasing elevation terricolous substrates showed the strongest increase (highest values at 3100?m). These patterns are associated with climatic variation along the gradient. At the highest elevations, the forest was of low stature and more light reached the forest floor. Also at these high elevations fog provides a daily wetting of the bryophytes and lichens. At lower elevations the water supply is increasingly in the form of rain, which is less frequent than the fog.

Conclusions. The apparent strong coupling of biomass variations to precipitation regimes implies a high sensitivity of the bryophytes and lichens to climatic warming and changes in the cloud base elevation. Furthermore our data suggest that the importance of bryophytes and lichens for regulating ecosystem water fluxes increases with elevation, which underlines the necessity to conserve intact montane forests.     

不同种源桃金娘表型性状多样性研究

为解析桃金娘表型性状多样性及其种源间关系，该文以20个不同来源的桃金娘为研究对象，在同质园栽培条件下，对其营养器官和花器官表型性状进行观测，采用方差分析、变异分析、Shannon-Wiener多样性指数分析和聚类分析等方法，探讨不同种源桃金娘表型性状多样性。结果表明：(1)不同种源桃金娘表型性状存在显著差异(P<0.05),Shannon-Wiener多样性指数均值在1.35以上，表型性状多样性丰富。(2)种源内表型性状变异系数均值在10.81%～63.75%之间，种源间的变异系数均值在13.08%～74.04%之间，种源间变异(23.33%)高于种源内变异(19.79%),营养器官变异(29.52%)高于花器官变异(14.06%)。(3)部分性状存在极显著或显著相关性，株高与分枝数呈极显著负相关，而与叶长、叶宽和叶面积等却呈显著正相关。(4)在欧式距离10处，20个种源桃金娘可分为A、B、C三类，A类包含8个种源，该类种源表现为植株高大、分枝少、叶大和花大等特征；B类包含11个种源，该类种源表现为株高中等、叶较大和花中等等特征；C类仅包含1个种源，表现为植株低矮、分枝多、叶小和...     

Geographic variation in morphological and reproductive characters of coastal and tableland populations ofBlandfordia grandiflora (Liliaceae)

For tenBlandfordia grandiflora populations spanning about 90% of the species' range, univariate and multivariate analyses on 14 vegetative and reproductive characters separated plants into distinct coastal and tableland groups. Distinguishing characters were number of flowers and leaves, leaf length and width, and inflorescence stalk height and diameter; coastal plants were larger than tableland plants. In a transplant experiment, coastal and tableland plants retained their phenotypic distinctness, indicating that vegetative morphology was genetically determined. Coastal plants exhibited clinal variation with latitude. Compared to tableland plants, coastal plants had higher pollen: ovule ratios, and produced fewer but heavier seeds per flower. Tableland and coastal plants are phenotypically distinct, indicating that separate subspecific status is warranted.     

Variation in reproductive modes and population genetic structures of a monocarpic perennial herb,Cardiocrinum cordatum,in relation to habitat fragmentation

Reproductive systems are recognized as having a profound influence on the extent and structure of genetic variation in plant populations. To investigate the spatiotemporal variation in the reproductive modes (sexual and vegetative reproduction) and population genetic structures of a monocarpic perennial herb, Cardiocrinum cordatum (liliaceae), we selected a variety of habitats (e.g. large forested area including primeval forest, small fragmented secondary forest, and so on) around Sapporo City, Japan. We conducted breeding experiments, monitored the fate and growth of marked individuals for 3 years, and also analyzed the spatiotemporal genetic variation of flowering plants within the populations using allozyme variation. Plants emasculated prior to anthesis produced mature fruits in all populations examined. However, seed production was significantly lower in the small fragmented populations, possibly because of the low availability of pollinators and subsequent pollen limitation. In these fragmented populations, the mature flowering plants tended to be more dependent on vegetative reproduction for their recruitment, because they can only produce flowers once in their lifetime. Genetic diversity using samples from mature flowering plants in each population was lower in the small fragmented populations than in the large populations. In addition, although genotypic compositions in the fragmented populations were more or less similar during the 3 years of the study, the dominant genotypes changed temporally and spatially every year in the large populations. The present study demonstrated that the reproductive features of C. cordatum can be altered in various environmental conditions, such as habitat fragmentation, and these changes considerably affected the population genetic structures and vice versa.     

The origin and distribution of Senecio cambrensis rosser in Edinburgh

Background: Range expansion often results in colonisation bottlenecks that should both deplete genetic diversity and increase genetic differentiation towards the margins of a species' geographic distribution.

Aims: We tested whether genetic differentiation increased among populations of the annual plant Mercurialis annua after its colonisation of the Iberian Peninsula from Morocco. Previous work showed that this colonisation resulted in a decrease of phenotypic and genetic diversity from the core in North Africa towards the distribution margins of M. annua in north-eastern and north-western Spain.

Methods: Seeds were sampled from 20 populations located across the hexaploid range of M. annua. Patterns of phenotypic and genetic differentiation among experimentally grown populations were analysed and compared between the Iberian Peninsula and North Africa.

Results: The level of phenotypic and genetic differentiation among populations in the expanded range of the Iberian Peninsula was similar to that in the core range in North Africa.

Conclusions: Our findings imply that the observed effects of range expansion on genetic differentiation may be independent of the effects on genetic diversity. They point to the importance of taking both historic and contemporary processes of migration into account when predicting the results of range expansion.     

Patterns of resource allocation in the dioecious alpine herb Aciphylla simplicifolia (Apiaceae)

Abstract Patterns of reproductive and vegetative biomass allocation were compared in male and female plants of the alpine herb Aciphylla simplicifolia. Male and female plants had similar vegetative biomass but differed in the pattern of resource allocation. Inflorescences of males and females were similar in weight at the time of flowering, but differed in biomass allocation to some structures within the inflorescences, particularly those associated with ovule production and pollinator attraction (number and size of flowers). At the time of fruit production, female inflorescences were 2.6 times heavier than at flowering with developing fruit six times heavier than flowers. In addition to the increase in biomass allocated to structures associated with the provisioning and dissemination of seed, support structures (main and side stalks) were also heavier. As a result of this additional investment of resources at the time of fruit production, the reproductive effort (RE) of female plants was much higher than that of males: 37% of above ground biomass compared with 21% for males. Differences in RE did not change with plant size; however, allocation to reproduction appeared to be a constant proportion of biomass over nearly all plant sizes sampled. These results show that sex‐specific resource allocation can be a complex of temporal and morphological patterns.     

SEX ALLOCATION IN THE MONOECIOUS HERB BEGONIA SEMIOVATA

Sex-allocation models predict that the evolution of self-fertilization should result in a reduced allocation to male function and pollinator attraction in plants. The evolution of sex allocation may be constrained by both functional and genetic factors, however. We studied sex allocation and genetic variation for floral sex ratio and other reproductive traits in a Costa Rica population of the monoecious, highly selfing annual Begonia semiovata. Data on biomass of floral structures, flower sex ratios, and fruit set in the source population were used to calculate the average proportion of reproductive allocation invested in male function. Genetic variation and genetic correlations for floral sex ratio and for floral traits related to male and female function were estimated from the greenhouse-grown progeny of field-collected maternal families. The proportion of reproductive biomass invested in male function was low (0.34 at flowering, and 0.07 for total reproductive allocation). Significant among-family variation was detected in the size (mass) of individual male and female flowers, in the proportion of male flowers produced, and in the proportion of total flower mass invested in male flowers. Significant among-family variation was also found in flower number per inflorescence, petal length of male and female flowers, and petal number of female flowers. Except for female petal length, we found no difference in the mean value of these characters between selfed and outcrossed progeny, indicating that, with the possible exception of female petal length, the among-family variation detected was not the result of variation among families in the level of inbreeding. Significant positive phenotypic and broad-sense genetic correlations were detected between the mass of individual male and female flowers, between male and female petal length, and between number of male and number of female flowers per inflorescence. The ratio of stamen-to-pistil mass (0.33) was low compared to published data for autogamous species with hermaphroditic flowers, suggesting that highly efficient selfing mechanisms may evolve in monoecious species. Our results indicate that the study population harbors substantial genetic variation for reproductive characters. The positive genetic correlation between investment in male and female flowers may reflect selection for maximum pollination efficiency, because in this self-pollinating species, each female flower requires a neighboring male flower to provide pollen.     

REPRODUCTIVE OUTPUT AND BIOMASS ALLOCATION IN SESBANIA EMERUS IN A TROPICAL SWAMP

This study examined the correlation of moisture, reproductive phenology, density of mature plants, and herbivory of apical meristems with the morphology and reproductive output of Sesbania emerus, an annual legume growing along a moisture gradient in a swamp in Guanacaste Province, Costa Rica. It also determined how biomass allocation varied and how it was related to reproductive output of plants growing along the moisture gradient within the swamp. Morphological changes included production of more stems and branches in response to herbivory, more and higher prop roots and more aerenchyma as water depth increased, and greater stem diameter in lower densities. Plant height varied greatly within a site, but not among habitats. Plants began to produce flowers and fruits later in wet sites than in dry sites. Reproductive output was generally more sensitive to environmental variables than was plant size. Fruit number and plant height were positively correlated for almost every treatment. Greater fruit and seed production were correlated with drier sites, earlier phenology, and lower density, but not with herbivory. Total biomass accumulation did not vary among moisture sites, but root production appeared to occur at the expense of reproductive output in the wetter sites. Plants in the wetter sites had both a greater percent and a greater absolute amount of biomass in roots, and a lower percent and a lower absolute amount of biomass in fruits and seeds than plants in drier sites. The root: shoot ratio was nearly five times higher in the wet than the dry site. Seed number per plant ranged from a mean of 6,800 at the wet site to a mean of 16,878 at the dry site. If this striking phenotypic variation in reproductive output and biomass accumulation has a genetic basis, the possibility of ecotypic differentiation exists in S. emerus.     

Changes in plant taxonomic and functional diversity patterns following treeline advances in the South Urals

Background: Treeline ecotones represent environmental boundaries that fluctuate in space and time and thus induce changes in plant taxonomic and functional diversity.

Aims: To study changes through time in taxonomic and functional plant diversity patterns along the treeline ecotone.

Methods: In 2002, vegetation was sampled along a gradient from upper montane forest to the treeline–alpine transition in the South Ural Mountains, Russia. In 2014, vegetation was resampled and plant functional traits were collected. We studied spatial and temporal changes in plant species composition, functional composition and functional diversity.

Results: Species composition and diversity changed along the elevational gradient. The functional composition in height, leaf area, specific leaf area and leaf nitrogen content decreased with elevation, whereas functional composition of leaf carbon content increased. We found a temporal shift towards shorter plants with smaller leaves in treeline sites. Functional richness varied in several traits along the elevational gradient, while functional dispersion showed a trend towards increased functional dispersion in height, specific leaf area and leaf nitrogen in the treeline–tundra transition.

Conclusions: Tree encroachment across the treeline ecotone has resulted in a shift in plant species relative abundances and functional diversity, possibly affecting plant community assembly patterns.