The effects of sand encroachment on composition,diversity,and functional patterns of vegetation in drylands are rarely studied,and yet addressing these aspects is important to deepen our understanding of the biodivers...The effects of sand encroachment on composition,diversity,and functional patterns of vegetation in drylands are rarely studied,and yet addressing these aspects is important to deepen our understanding of the biodiversity conservation.This study aimed to investigate the effect of sand encroachment on plant functional biodiversity of desert pavements(gravel deserts)in the Sahara Desert of Algeria.Plants were sampled and analyzed in three desert pavements with different levels of sand encroachment(LSE)and quantity of aeolian deposits(low,LLSE;medium,MLSE;and high,HLSE).Within the sample-plot area(100 m^(2)),density of every plant species was identified and total vegetation cover was determined.Plant taxonomic and functional diversity were analyzed and compared between LSE.Result showed that 19 plant species in desert pavements were classified into 18 genera and 13 families.Asteraceae and Poaceae were the most important families.The species Anabasis articulata(Forssk)Moq.characterized LLSE desert pavements with 11 species,whereas Thymelaea microphylla Coss.&Durieu ex Meisn.and Calobota saharae(C&D)Boatwr.&van Wyk were dominant species of desert pavements with MLSE(14 species)and HLSE(10 species),respectively.The highest values of species richness and biodiversity were recorded in desert pavements with MLSE,while low values of these ecological parameters were obtained in desert pavements with HLSE.Desert pavements with LLSE were characterized with the highest values of species abundances.Plant communities were dominated by chamaephytes,anemochorous,arido-active,and competitive stress-tolerant plants.The increase in LSE along the gradient from LLSE to HLSE induced significant changes in plant community variables including decreases in plant density,plant rarity,lifeform composition,morphological type,and aridity adaptation.Desert pavements with HLSE favor the degradation of vegetation and trigger biodiversity erosion.展开更多
The stability mechanisms of ecosystem functions have been a hot topic in ecology. However, in wetland ecosystems, the mechanisms by which biotic and abiotic factors interact to affect ecosystem stability in changing e...The stability mechanisms of ecosystem functions have been a hot topic in ecology. However, in wetland ecosystems, the mechanisms by which biotic and abiotic factors interact to affect ecosystem stability in changing environments remain largely unclear. This study investigated the key factors and underlying mechanisms that regulate the spatial variability of wetland productivity by measuring community productivity, multiple components of biodiversity (i.e. species diversity, community functional composition and diversity) and environmental factors along a well-characterized gradient of wetland degradation in the lower reaches of the Yellow River. The results showed that the spatial variability of productivity in wetlands increased with intensified degradation. The spatial variability of wetland productivity was not related to species richness but was mainly affected by changes in community functional composition and diversity. Furthermore, degradation-induced changes in soil nutrients drove the spatial variability of productivity to increase with shifts in functional composition towards more conservative traits (i.e. higher leaf dry matter content and root tissue density), and to decrease with higher functional trait diversity. These findings reveal the driving mechanism of spatial variability in wetland productivity under degradation, and suggest that reduced nutrient availability, by altering plant resource strategies, can affect the spatial reliability of key ecosystem functions in wetlands.展开更多
Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host...Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous.Utilizing high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest China.Functional annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities.Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal community.Comparison across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant characteristics.FAPROTAX prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form plants.FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa.Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly.Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted both bacterial and fungal community composition,with fungal community composition showing a closer association with leaf nutrients and physiology compared with bacterial community composition.The distinct responses of bacterial and fungal communities to plant traits were attributed to the differing properties of bacteria and fungi,such as bacteria having higher potential dispersal rates and broader ecological niches than fungi.Overall,the results indicate that phyllosphere bacterial and fungal communities undergo similar community assembly processes,with fungi being more influenced by plant characteristics than bacteria.These findings offer novel insights into the ecology of phyllosphere microbial communities of desert plants.展开更多
Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant func...Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant functional traits at multiple biological levels and linking them to environmental variables across geographical ranges is important for forecasting range-shifts of broadly-distrib-uted species under climate change.We sampled leaves of five deciduous Quercus spp.covering approximately 20°of latitude(~21°N-41°N)and 20 longitude(~99°E-119°E)across China and measured 12 plant functional traits at different biological levels.The traits varied distinctively,either within each biological level or among different levels driven by climatic and edaphic variables.Traits at the organ level were significantly correlated with those at the cellular and tissue levels,while traits at the whole-plant level only correlated with those at the tissue level.The Quercus species responded to changing environments by regulating stomatal size,leaf thickness and the palisade mesophyll thickness to leaf thickness ratios with contrasting degree of effect to adjust the whole-plant functioning,i.e.,intrinsic water use efficiency(iWUE),carbon supply and nitrogen availability.The results suggest that these deciduous Quercus spp.will maintain vigour by increasing iWUE when subjected to large temperature changes and insufficient moisture,and by accu-mulating leaf non-structural carbohydrates under drought conditions.The findings provide new insights into the inher-ent variation and trait coordination of widely distributed tree species in the context of climate change.展开更多
Considering the legacy of plant functional composition can help assess ecosystem functions and ecosystem services across different spatial scales under land cover changes.Woody plants likely respond to natural and ant...Considering the legacy of plant functional composition can help assess ecosystem functions and ecosystem services across different spatial scales under land cover changes.Woody plants likely respond to natural and anthropogenic perturbations due to historical events(e.g.,agricultural development),thus contemporary plant functional composition may be explained by historical woodland change,a type of land cover change.We propose that historical woodland changes may have legacy effects on contemporary plant functional composition.Here,we used partial least squares regression and linear mixed model analyses to test this assumption by coupling data on community weighted means(CWM)and community weighted variance(CWV)of vegetation plots and calculating the time of woodland existence across different periods from AD 0 to 2017.We found that the legacy effects of historical land cover changes on CWM and CWV during the existence time of woodland,particularly from AD 0 to 900,were drivers of contemporary plant functional composition at large spatial scales.Furthermore,historical woodland changes can affect contemporary plant functional composition,depending on the biome type.Particularly,the CWM of plant height,seed mass,and seed length showed the strongest correlations with woodland changes from AD 1910 to 2010 in tropics with year-round rain,and the CWM of leaf traits correlated with woodland changes from AD 0 to 1700 in tropics with summer rain.Our study provides the effective evidence on the legacy of historical woodland changes and the effects on contemporary plant functional composition,which is crucial with respect to effective management of plant diversity and assessing ecosystem functions and services from local to global scales over time.展开更多
Hot arid zones represent vital reservoirs of unique species and ecosystems,holding significant importance for biodiversity.This study aimed to explore the plant diversity associated with tree plantations in urban ecos...Hot arid zones represent vital reservoirs of unique species and ecosystems,holding significant importance for biodiversity.This study aimed to explore the plant diversity associated with tree plantations in urban ecosystems under hyper-arid climatic conditions in the Sahara Desert of Algeria.In May 2022,30 quadrats measuring 1 m^(2) each were established at the base of Phoenix dactylifera,Leucaena leucocephala,and Tamarix aphylla,corresponding to the dominant tree species in each of three plantations.In each quadrat,the plant quantitative inventory was conducted to measure plant diversity and similarity among the studied plantations.Based on this,we assessed the plant functional traits and rarity/abundance status of the flora.The findings revealed a diverse flora associated with the studied plantations,comprising 29 plant species grouped into 27 genera and 12 families.Notably,Poaceae(accounting for 30.8% of the flora),Asteraceae(25.0%),and Zygophyllaceae(21.6%)were well-represented.With an overall density of approximately 555 individuals/m^(2),Zygophyllum album(120 individuals/m^(2))and Polypogon monspeliensis(87 individuals/m^(2))emerged as the most abundant species.Functional trait analysis underscored the pivotal role of therophytes(constituting over 50.0% of the flora)and anemochorous species(33.0%-62.5%).Phytogeographic analysis emphasized the prevalence of the Saharo-Arabic element(constituting over 31.0% of the flora)and the Mediterranean Saharo-Arabic element(9.5%-21.5%).The Cosmopolitan element thrived under disturbance factors,recording percentages from 13.0% to 20.0% of the plant community.The rarity/abundance status of the flora emphasized the significance of rare,common,and very common species in the studied plantations.These findings could provide fundamental data for the effective control and management of biodiversity in hot hyper-arid urban ecosystems.展开更多
The plant rhizosphere,a region interconnecting roots,soil,and microorganisms,is critical for plant resource acquisition,community structure,and the functional stability of ecosystems.Most studies focus primarily on ro...The plant rhizosphere,a region interconnecting roots,soil,and microorganisms,is critical for plant resource acquisition,community structure,and the functional stability of ecosystems.Most studies focus primarily on root traits,while overlooking the covariation within the rhizosphere root-soil-microbe continuum and its ecological implications under environmental change.Here,we highlight the necessity of integrating rhizosphere function into a broader theoretical framework encompassing belowground traits,such as the core functional modules of roots,rhizosphere microorganisms(including mycorrhizal fungi),and soil.We further identify critical knowledge gaps and future directions for research on rhizosphere function traits.This framework expands current perspectives on plant belowground functional traits,plant adaptation,and ecosystem stability under changing environments.展开更多
Understanding plant adaptive strategies that determine species distributions and ecological optima is crucial for predicting responses to global change drivers.While functional traits provide mechanistic insights into...Understanding plant adaptive strategies that determine species distributions and ecological optima is crucial for predicting responses to global change drivers.While functional traits provide mechanistic insights into distribution patterns,the specific trait syndromes that best predict elevational optima,particularly in less-studied regions such as the Himalayas,remain unclear.This study employs a novel hierarchical framework integrating morphological,anatomical,and physiological traits to explain elevational distributions among 310 plant species across a 3,500-m gradient(2,650–6,150 m).We analyzed 95,000 floristic records collected from4,062 localities spanning 80,000 km^(2) in Ladakh,NW Himalayas,India,to define elevational optima and link them with 17 functional traits from over 7,800individuals.We assessed the roles of moisture and cold limitations on trait–optima relationships by comparing two contrasting habitats(dry steppe and wetter,colder alpine).The predictive power of functional traits was more pronounced in the alpine species facing more extreme abiotic stress than the steppe species.Our results indicate that conservative life history strategies strongly predict elevational optima in alpine areas,while drought avoidance and competitive dominance are key in steppe habitats.Trait syndromes combining short stature,compact growth forms,enhanced storage tissues,and features promoting water-use efficiency(δ13C),freezing resistance(fructan levels),and nutrient retention(high root nitrogen and leaf phosphorus) explained 61% of the variation in alpine species' optima.Conversely,lifespan and clonal propagation determined the optima of steppe species at lower elevations.The study emphasizes the importance of functional trait combinations in determining elevational optima,highlighting that alpine species prioritize resource conservation and stress tolerance,while steppe species focus on competitive growth strategies.This multi-trait approach contrasts with previous research focusing on single trait–elevation relationships,providing novel insights into the diverse mechanisms shaping elevational distributions and offering valuable predictive power for assessing vegetation responses to future climate change.展开更多
Amid global climate change, rising levels of nitrogen(N) deposition have attracted considerable attention for their potential effects on the carbon cycle of terrestrial ecosystems. The desert steppes are a crucial yet...Amid global climate change, rising levels of nitrogen(N) deposition have attracted considerable attention for their potential effects on the carbon cycle of terrestrial ecosystems. The desert steppes are a crucial yet vulnerable ecosystem in arid areas, but their response to the combination of N addition and precipitation(a crucial factor in arid areas) remains underexplored. This study systematically explored the impact of N addition and precipitation on net ecosystem exchange(NEE) in a desert steppe in northern China. Specifically, we conducted a 2-a experiment from 2022 to 2023 with eight N addition treatments in the Urat desert steppe of Inner Mongolia Autonomous Region, China, to examine changes in NEE and explore its driving factors. The structural equation model(SEM) and multiple regression model were applied to determine the relationship of NEE with plant community characteristics and soil physical-chemical properties. Statistical results showed that N addition has no significant effect on NEE.However, it has a significant impact on the functional traits of desert steppe plant communities. SEM results further revealed that N addition has no significant effect on NEE in the desert steppe, whereas annual precipitation can influence NEE variations. The multiple regression model analysis indicated that plant functional traits play an important role in explaining the changes in NEE, accounting for 62.15% of the variation in NEE. In addition, plant height, as an important plant functional trait indicator, shows stronger reliability in predicting the changes in NEE and becomes a more promising predictor. These findings provide valuable insights into the complex ecological mechanisms governing plant community responses to precipitation and nutrient availability in the arid desert steppes, contributing to the improved monitoring and prediction of desert steppe ecosystem responses to global climate change.展开更多
Mowing is an important land management practice for natural semi-arid regions. A growing body of empirical evidence shows that different mowing regimes affect the functioning of grassland ecosystems. However, the resp...Mowing is an important land management practice for natural semi-arid regions. A growing body of empirical evidence shows that different mowing regimes affect the functioning of grassland ecosystems. However, the responses of plant functional traits to long-term mowing and their allometric scaling under long-term mowing are poorly understood. For a better understanding of the effects of mowing on grassland ecosystems, we analyzed the allometric traits of leaves and stems of Leymus chinensis （Trin.） Tzvel., a dominant grass species in eastern Eurasian temperate grassland, at different mowing intensities （no clipping, clipping once every two years, once a year and twice a year）. Experiments were conducted on plots established over a decade ago in a typical steppe of Xilinhot, Inner Mongolia, China. Results showed that most of the functional traits of L. chinensis decreased with the increased mowing intensity. The responses of leaves and stems to long-term mowing were asymmetric, in which leaf traits were more stable than stem traits. Also significant allometric relationships were found among most of the plant functional traits under the four mowing treatments. Sensitive traits of L. chinensis （e.g. leaf length and stem length） were primary indicators associated with aboveground biomass decline under high mowing intensity. In conclusion, the allometric growth of different functional traits of L. chinensis varies with different long-term mowing practices, which is likely to be a strategy used by the plant to adapt to the mowing disturbances.展开更多
The diameter at breast height(DBH) of trees and stands is not only a widely used plant functional trait in ecology and biodiversity but also one of the most fundamental measurements in managing forests. However, syste...The diameter at breast height(DBH) of trees and stands is not only a widely used plant functional trait in ecology and biodiversity but also one of the most fundamental measurements in managing forests. However, systematically measuring the DBH of individual trees over large areas using conventional ground-based approaches is labour-intensive and costly. Here, we present an improved area-based approach to estimate plot-level tree DBH from airborne Li DAR data using the relationship between tree height and DBH, which is widely available for most forest types and many individual tree species. We first determined optimal functional forms for modelling heightDBH relationships using field-measured tree height and DBH. Then we estimated plot-level mean DBH by inverting the height-DBH relationships using the tree height predicted by Li DAR. Finally, we compared the predictive performance of our approach with a classical area-based method of DBH. The results showed that our approach significantly improved the prediction accuracy of tree DBH(R^(2)=0.85–0.90, rRMSE=9.57%–11.26%)compared to the classical area-based approach(R^(2)=0.80–0.83, rRMSE=11.98%–14.97%). Our study demonstrates the potential of using height-DBH relationships to improve the estimation of the plot-level DBH from airborne Li DAR data.展开更多
Grazing exerts a profound influence on both the plant diversity and productivity of grasslands,while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration.Moreover,besides alte...Grazing exerts a profound influence on both the plant diversity and productivity of grasslands,while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration.Moreover,besides altering the taxonomic diversity of plant communities,grazing can also affect their diversity of functional traits.However,we still poorly understand how grazing modifies the relationship between plant functional diversity(FD)and soil carbon sequestration in grassland ecosystems.Here,we conducted a grazing manipulation experiment to investigate the effects of different grazing regimes(no grazing,sheep grazing(SG)and cattle grazing(CG))on the relationships between plant FD and soil carbon sequestration in meadow and desert steppe.Our findings showed that different livestock species changed the relationships between plant FD and soil organic carbon(SOC)in the meadow steppe.SG decoupled the originally positive relationship between FD and SOC,whereas CG changed the relationship from positive to negative.In the desert steppe,both SG and CG strengthened the positive relationship between FD and SOC.Our study illuminates the considerable impact of livestock species on the intricate mechanisms of soil carbon sequestration,primarily mediated through the modulation of various measures of functional trait diversity.In ungrazed meadows and grazed deserts,maintaining high plant FD is conducive to soil carbon sequestration,whereas in grazed meadows and ungrazed deserts,this relationship may disappear or even reverse.By measuring the traits and controlling the grazing activities,we can accurately predict the carbon sequestration potential in grassland ecosystems.展开更多
Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q...Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger;however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.展开更多
As a key functional trait affecting many physiological processes,leaf pH is closely related to other leaf traits at the local scale.Nevertheless,whether and how leaf pH is linked with other leaf functional traits acro...As a key functional trait affecting many physiological processes,leaf pH is closely related to other leaf traits at the local scale.Nevertheless,whether and how leaf pH is linked with other leaf functional traits across geographic scales remains unclear.A field survey in northern China was conducted to investigate the relationships between leaf pH and some key leaf structural(specific leaf area,SLA;leaf dry matter content,LDMC)and chemical traits(elemental concentrations;total dissolved solids,TDS;practical salinity),as well as the effects of environmental factors on these relationships.Our results showed that the trait coordination may vary in degree or direction across eco-geographic regions(arid vs.non-arid regions)and life-forms(woody vs.herbaceous plants).Generally,leaf pH was negatively related to SLA,but positively related to TDS and salinity.However,leaf pH and LDMC were negatively correlated in arid regions but positively correlated in non-arid regions;leaf pH covaried with N(similarly,with Ca,Mg and Na)in the same direction for both herbaceous and woody plants in arid regions,but not in non-arid regions.Climatic factors mainly influenced the relationships of leaf pH with leaf Ca and Fe concentrations,while soil factors mostly affected those with leaf P,Ca and Mn concentrations.Our findings highlight the divergent coordination between leaf pH and other leaf traits across life-forms and eco-geographic regions and may shed light on the in-depth understanding of the role of acid-base balance in plant eco-physiological processes and ecological adaptation over biogeographic scales.展开更多
The interspecific variations of plant functional traits can characterize the niche positions of species within communities,while the intraspecific variations can accurately display the species’niche breadth.Revealing...The interspecific variations of plant functional traits can characterize the niche positions of species within communities,while the intraspecific variations can accurately display the species’niche breadth.Revealing relative contributions of intra-and interspecific variations to plant functional community structure is crucial in understanding how the species coexist together,especially in species-diverse ecosystems.To explore how the intra-and interspecific variations of plant functional traits change along the successional pathway in heterogeneous conditions,we established a series of plots and measured main plant functional traits along the natural regeneration in karst forest ecosystems.By quantifying the intra-and interspecific variations of plant functional traits,we found that the changes in intraspecific variations were relatively lower compared to changes in interspecific variations throughout the natural regeneration.Further analysis showed that the community spatial structure contributed more to the intraspecific variations of plant functional traits,while the soil physicochemical properties contributed more to interspecific variations.Our study suggested that tree species might tend to narrow their niche and change the positions to release the niche overlap when faced with heterogeneous habitat conditions.展开更多
A better understanding the mechanisms driving plant biomass allocation in different ecosystems is an important theoretical basis for ilustrating the adaptive strategies of plants.To date,the effects of habitat conditi...A better understanding the mechanisms driving plant biomass allocation in different ecosystems is an important theoretical basis for ilustrating the adaptive strategies of plants.To date,the effects of habitat conditions on plant biomass allocation have been widely studied.However,it is less known how plant community traits and functions(PCTF)affect biomass allocation,particularly in alpine grassland ecosystems.In this study,community-weighted means(CWM)were calculated at the community level using five leaf functional traits,and the relationships between PCTF and biomass trade-offs were explored using correlation analysis,variation partitioning analysis and structural equation modeling.We found that the trade-off values were greater than zero in both alpine meadow(AM)and alpine steppe(AS)across the Tibetan Plateau,with different values of 0.203 and 0.088 for AM and AS,respectively.Moreover,the critical factors determining biomass allocation in AS were species richness(SR;scored at 0.69)and leaf dry matter content of CWM(CWM_(LDMC),scored at 0.42),while in AM,the key factors were leaf dry matter content(CWM.pMC scored at 0.48)and leaf carbon content of CWM(CWM_(LC),scored at-0.45).In particular,both CWM_(LDMC)and SR in AS,as well as CWM_(LDMC)and CWM_(LDMC)in AM were primarily regulated by precipitation.In summary,precipitation tends to drive biomass allocation in alpine grasslands through its effects on PCTF,hence highlighting the importance of PCTF in regulating plant biomass allocation strategies along precipitation gradients.展开更多
Aims Accurate prediction of spatiotemporal variations in carbon and water fluxes of heterogeneous landscape is critical to comprehensively address the effects of climate change and vegetation dynamics on landscape and...Aims Accurate prediction of spatiotemporal variations in carbon and water fluxes of heterogeneous landscape is critical to comprehensively address the effects of climate change and vegetation dynamics on landscape and regional carbon and water cycling.Methods A field study was conducted to characterize the seasonal variations in gas fluxes and explore their relationships with abiotic and biotic factors in a small grassland landscape.Daytime carbon and water fluxes including net ecosystem exchange,gross ecosystem productivity,ecosystem respiration and evapotranspiration(ET)were measured for three types of grassland patches over a growing season using the closed chamber method.The key plant trait variables were measured,based on which community weighted mean(CWM)and functional variance(FDvar)were calculated.Important Findings The results showed that the temporal variations in the carbon and water fluxes were regulated by meteorological,soil and community functional variables.Inclusion of the CWM and FDvar of plant trait measures greatly improved the degree of explanation of the predict models.Specific leaf area and leafδ^(13)C content(Lδ^(13)C)were the most important trait variables in affecting the variations of the gas fluxes.CWMs indices had greater importance than FDvar indices in predicting the variation of the C fluxes but FDvar indices were more important for ET than C fluxes.Our findings demonstrated that mass ratio hypothesis and the complementary effects hypothesis are not mutually exclusive but have different relative importance for different ecosystem processes.Community functional traits played important roles in predicting the spatiotemporal variations of carbon and water fluxes in semiarid grassland.展开更多
Aims Studies integrating phylogenetic history and large-scale community assembly are few,and many questions remain unanswered.Here,we use a global coastal dune plant data set to uncover the important factors in commun...Aims Studies integrating phylogenetic history and large-scale community assembly are few,and many questions remain unanswered.Here,we use a global coastal dune plant data set to uncover the important factors in community assembly across scales from the local filtering processes to the global long-term diversification and dispersal dynamics.Coastal dune plant communities occur worldwide under a wide range of climatic and geologic conditions as well as in all biogeographic regions.However,global patterns in the phylogenetic composition of coastal dune plant communities have not previously been studied.Methods The data set comprised vegetation data from 18463 plots in New Zealand,South Africa,South America,North America and Europe.The phylogenetic tree comprised 2241 plant species from 149 families.We calculated phylogenetic clustering(Net Relatedness Index,NRI,and Nearest Taxon Index,NTI)of regional dune floras to estimate the amount of in situ diversification relative to the global dune species pool and evaluated the relative importance of land and climate barriers for these diversification patterns by geographic analyses of phylogenetic similarity.We then tested whether dune plant communities exhibit similar patterns of phylogenetic structure within regions.Finally,we calculated NRI for local communities relative to the regional species pool and tested for an association with functional traits(plant height and seed mass)thought to vary along sea–inland gradients.Important Findings Regional species pools were phylogenetically clustered relative to the global pool,indicating regional diversification.NTI showed stronger clustering than NRI pointing to the importance of especially recent diversifications within regions.The species pools grouped phylogenetically into two clusters on either side of the tropics suggesting greater dispersal rates within hemispheres than between hemispheres.Local NRI plot values confirmed that most communities were also phylogenetically clustered within regions.NRI values decreased with increasing plant height and seed mass,indicating greater phylogenetic clustering in communities with short maximum height and good dispersers prone to wind and tidal disturbance as well as salt spray,consistent with environmental filtering along sea–inland gradients.Height and seed mass both showed significant phylogenetic signal,and NRI tended to correlate negatively with both at the plot level.Low NRI plots tended to represent coastal scrub and forest,whereas high NRI plots tended to represent herb-dominated vegetation.We conclude that regional diversification processes play a role in dune plant community assembly,with convergence in local phylogenetic community structure and local variation in community structure probably reflecting consistent coastal-inland gradients.Our study contributes to a better understanding of the globally distributed dynamic coastal ecosystems and the structuring factors working on dune plant communities across spatial scales and regions.展开更多
To compare current methods of pretreatment/determination for plant foliar pH,we proposed a method for longperiod sample preservation with little interference with the stability of foliar pH.Four hundred leaf samples f...To compare current methods of pretreatment/determination for plant foliar pH,we proposed a method for longperiod sample preservation with little interference with the stability of foliar pH.Four hundred leaf samples from 20 species were collected and four methods of pH determination were used:refrigerated(stored at 4°C for 4 days),frozen(stored at−16°C for 4 days),oven-dried and fresh green-leaf pH(control).To explore the effects of different leaf:water mixing ratio on the pH determination results,we measured oven-dried green-leaf pH by leaf:water volume ratio of 1:8 and mass ratio of 1:10,and measured frozen senesced-leaf pH by mass ratio of 1:10 and 1:15.The standard major axis regression was used to analyze the relationship and the conversion equation between the measured pH with different methods.Foliar pH of refrigerated and frozen green leaves did not signifcantly differ from that of fresh green-leaf,but drying always overrated fresh green-leaf pH.During the feld sampling,cryopreservation with a portable refrigerator was an advisable choice to get a precise pH.For long-duration feld sampling,freezing was the optimal choice,and refrigeration is the best choice for the shorttime preservation.The different leaf:water mixing ratio signifcantly infuenced the measured foliar pH.High dilution reduced the proton concentration and increased the measured pH.Our fndings provide the conversion relationships between the existing pretreatment and measurement methods,and establish a connection among pH determined by different methods.Our study can facilitate foliar pH measurement,thus contributing to understanding of this interesting plant functional trait.展开更多
Aims Community assembly persists as a key topic in ecology due to the complex variation in the relative importance of assembly forces and mechanisms across spatio-temporal scales and eco-systems.Here we address a fore...Aims Community assembly persists as a key topic in ecology due to the complex variation in the relative importance of assembly forces and mechanisms across spatio-temporal scales and eco-systems.Here we address a forest-savanna vegetation mosaic in the Brazilian Atlantic forest to examine the role played by soil attributes as determinants of community assembly and organiza-tion at a landscape spatial scale.Methods We examined soil and plant assemblage attributes across 23 plots of forest and savanna in a 1600 km2 landscape exposed to the same climatic conditions in the Atlantic forest region of northeast Brazil.Assemblage attributes included species richness,taxonomic and functional composition(community weighted mean,CWM)and functional diversity(quadratic diversity;Rao’s quadratic entropy index)relative to plant leaf area,specific leaf area,leaf dry matter content,thickness and succulence.Important Findings Our results suggest that forest and savanna patches exposed to the same climatic conditions clearly differ in terms of soil attributes,plant assemblage structure,taxonomic and functional composition.By selecting particular plant strategies relative to resource economy,soil potentially affects community structure,with forest assemblages bear-ing more acquisitive resource-use strategies,while conservative plant strategies are more frequent in savannas.Accordingly,savanna-forest mosaics in the Atlantic forest region represent spatially organized plant assemblages in terms of taxonomic and functional features,with a sig-nal of trait convergence in both vegetation types.Soil-mediated filter-ing thus emerges as a potential deterministic assembly force affecting the spatial organization of savanna-forest boundaries and mosaics.展开更多
文摘The effects of sand encroachment on composition,diversity,and functional patterns of vegetation in drylands are rarely studied,and yet addressing these aspects is important to deepen our understanding of the biodiversity conservation.This study aimed to investigate the effect of sand encroachment on plant functional biodiversity of desert pavements(gravel deserts)in the Sahara Desert of Algeria.Plants were sampled and analyzed in three desert pavements with different levels of sand encroachment(LSE)and quantity of aeolian deposits(low,LLSE;medium,MLSE;and high,HLSE).Within the sample-plot area(100 m^(2)),density of every plant species was identified and total vegetation cover was determined.Plant taxonomic and functional diversity were analyzed and compared between LSE.Result showed that 19 plant species in desert pavements were classified into 18 genera and 13 families.Asteraceae and Poaceae were the most important families.The species Anabasis articulata(Forssk)Moq.characterized LLSE desert pavements with 11 species,whereas Thymelaea microphylla Coss.&Durieu ex Meisn.and Calobota saharae(C&D)Boatwr.&van Wyk were dominant species of desert pavements with MLSE(14 species)and HLSE(10 species),respectively.The highest values of species richness and biodiversity were recorded in desert pavements with MLSE,while low values of these ecological parameters were obtained in desert pavements with HLSE.Desert pavements with LLSE were characterized with the highest values of species abundances.Plant communities were dominated by chamaephytes,anemochorous,arido-active,and competitive stress-tolerant plants.The increase in LSE along the gradient from LLSE to HLSE induced significant changes in plant community variables including decreases in plant density,plant rarity,lifeform composition,morphological type,and aridity adaptation.Desert pavements with HLSE favor the degradation of vegetation and trigger biodiversity erosion.
基金supported jointly by Henan Province Xixiayuan Water Conservancy Hub Water Supply and Irrigation District Engineering Research ProjectHenan Province Natural Resources Research Project(2023-382-4)+3 种基金Sichuan Science and Technology Program (2023ZYD0102)China Postdoctoral Science Foundation (2023M743206)the Scientific Research Foundation for Academician of CAS Teamof Zhengzhou University (13432340370)the National Natural Science Foundation of China(32201517)。
文摘The stability mechanisms of ecosystem functions have been a hot topic in ecology. However, in wetland ecosystems, the mechanisms by which biotic and abiotic factors interact to affect ecosystem stability in changing environments remain largely unclear. This study investigated the key factors and underlying mechanisms that regulate the spatial variability of wetland productivity by measuring community productivity, multiple components of biodiversity (i.e. species diversity, community functional composition and diversity) and environmental factors along a well-characterized gradient of wetland degradation in the lower reaches of the Yellow River. The results showed that the spatial variability of productivity in wetlands increased with intensified degradation. The spatial variability of wetland productivity was not related to species richness but was mainly affected by changes in community functional composition and diversity. Furthermore, degradation-induced changes in soil nutrients drove the spatial variability of productivity to increase with shifts in functional composition towards more conservative traits (i.e. higher leaf dry matter content and root tissue density), and to decrease with higher functional trait diversity. These findings reveal the driving mechanism of spatial variability in wetland productivity under degradation, and suggest that reduced nutrient availability, by altering plant resource strategies, can affect the spatial reliability of key ecosystem functions in wetlands.
基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A351)the Joint Fund of National Natural Science Foundation of China(U2003214)+1 种基金the Key Project of Xinjiang Uygur Autonomous Region Natural Science Foundation(2022D01D083)the Tianchi Talent Introduction Project of Xinjiang Uygur Autonomous Region.We thank Mr.LI Yonggang,Mrs.DU Fang,Mrs.SHEN Hui,Mrs.PAN Qi,and Mrs.MENG Huanhuan for providing help with the experiment in the field.
文摘Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous.Utilizing high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest China.Functional annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities.Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal community.Comparison across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant characteristics.FAPROTAX prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form plants.FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa.Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly.Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted both bacterial and fungal community composition,with fungal community composition showing a closer association with leaf nutrients and physiology compared with bacterial community composition.The distinct responses of bacterial and fungal communities to plant traits were attributed to the differing properties of bacteria and fungi,such as bacteria having higher potential dispersal rates and broader ecological niches than fungi.Overall,the results indicate that phyllosphere bacterial and fungal communities undergo similar community assembly processes,with fungi being more influenced by plant characteristics than bacteria.These findings offer novel insights into the ecology of phyllosphere microbial communities of desert plants.
基金supported by the Key Area Research and Development Program of Guangdong Province(2022B1111230001)theScience and Technology Foundation of Guangxi Zhuang Autonomous Region(Guike AD23026080)+1 种基金the National Natural Science Founda tion of China(No.42071065)Natural Science Foundation of US(No.2021898).
文摘Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant functional traits at multiple biological levels and linking them to environmental variables across geographical ranges is important for forecasting range-shifts of broadly-distrib-uted species under climate change.We sampled leaves of five deciduous Quercus spp.covering approximately 20°of latitude(~21°N-41°N)and 20 longitude(~99°E-119°E)across China and measured 12 plant functional traits at different biological levels.The traits varied distinctively,either within each biological level or among different levels driven by climatic and edaphic variables.Traits at the organ level were significantly correlated with those at the cellular and tissue levels,while traits at the whole-plant level only correlated with those at the tissue level.The Quercus species responded to changing environments by regulating stomatal size,leaf thickness and the palisade mesophyll thickness to leaf thickness ratios with contrasting degree of effect to adjust the whole-plant functioning,i.e.,intrinsic water use efficiency(iWUE),carbon supply and nitrogen availability.The results suggest that these deciduous Quercus spp.will maintain vigour by increasing iWUE when subjected to large temperature changes and insufficient moisture,and by accu-mulating leaf non-structural carbohydrates under drought conditions.The findings provide new insights into the inher-ent variation and trait coordination of widely distributed tree species in the context of climate change.
基金We acknowledge support from the National Natural Science Foundation of China(NSFC,32060385 and 31860668)the Project of Qinghai Science&Technology Department(2020-ZJ-733).
文摘Considering the legacy of plant functional composition can help assess ecosystem functions and ecosystem services across different spatial scales under land cover changes.Woody plants likely respond to natural and anthropogenic perturbations due to historical events(e.g.,agricultural development),thus contemporary plant functional composition may be explained by historical woodland change,a type of land cover change.We propose that historical woodland changes may have legacy effects on contemporary plant functional composition.Here,we used partial least squares regression and linear mixed model analyses to test this assumption by coupling data on community weighted means(CWM)and community weighted variance(CWV)of vegetation plots and calculating the time of woodland existence across different periods from AD 0 to 2017.We found that the legacy effects of historical land cover changes on CWM and CWV during the existence time of woodland,particularly from AD 0 to 900,were drivers of contemporary plant functional composition at large spatial scales.Furthermore,historical woodland changes can affect contemporary plant functional composition,depending on the biome type.Particularly,the CWM of plant height,seed mass,and seed length showed the strongest correlations with woodland changes from AD 1910 to 2010 in tropics with year-round rain,and the CWM of leaf traits correlated with woodland changes from AD 0 to 1700 in tropics with summer rain.Our study provides the effective evidence on the legacy of historical woodland changes and the effects on contemporary plant functional composition,which is crucial with respect to effective management of plant diversity and assessing ecosystem functions and services from local to global scales over time.
文摘Hot arid zones represent vital reservoirs of unique species and ecosystems,holding significant importance for biodiversity.This study aimed to explore the plant diversity associated with tree plantations in urban ecosystems under hyper-arid climatic conditions in the Sahara Desert of Algeria.In May 2022,30 quadrats measuring 1 m^(2) each were established at the base of Phoenix dactylifera,Leucaena leucocephala,and Tamarix aphylla,corresponding to the dominant tree species in each of three plantations.In each quadrat,the plant quantitative inventory was conducted to measure plant diversity and similarity among the studied plantations.Based on this,we assessed the plant functional traits and rarity/abundance status of the flora.The findings revealed a diverse flora associated with the studied plantations,comprising 29 plant species grouped into 27 genera and 12 families.Notably,Poaceae(accounting for 30.8% of the flora),Asteraceae(25.0%),and Zygophyllaceae(21.6%)were well-represented.With an overall density of approximately 555 individuals/m^(2),Zygophyllum album(120 individuals/m^(2))and Polypogon monspeliensis(87 individuals/m^(2))emerged as the most abundant species.Functional trait analysis underscored the pivotal role of therophytes(constituting over 50.0% of the flora)and anemochorous species(33.0%-62.5%).Phytogeographic analysis emphasized the prevalence of the Saharo-Arabic element(constituting over 31.0% of the flora)and the Mediterranean Saharo-Arabic element(9.5%-21.5%).The Cosmopolitan element thrived under disturbance factors,recording percentages from 13.0% to 20.0% of the plant community.The rarity/abundance status of the flora emphasized the significance of rare,common,and very common species in the studied plantations.These findings could provide fundamental data for the effective control and management of biodiversity in hot hyper-arid urban ecosystems.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Creation of Nutrient Enhancing Biofertilizers)the National Natural Science Foundation of China(32301446,U23A2051,and 32171757)+1 种基金the Science and Technology Program of the Tibet Autonomous Region(XZ202301YD0028C and XZ202301ZR0047G)the Sichuan Science and Technology Program(2023NSFSC0012).
文摘The plant rhizosphere,a region interconnecting roots,soil,and microorganisms,is critical for plant resource acquisition,community structure,and the functional stability of ecosystems.Most studies focus primarily on root traits,while overlooking the covariation within the rhizosphere root-soil-microbe continuum and its ecological implications under environmental change.Here,we highlight the necessity of integrating rhizosphere function into a broader theoretical framework encompassing belowground traits,such as the core functional modules of roots,rhizosphere microorganisms(including mycorrhizal fungi),and soil.We further identify critical knowledge gaps and future directions for research on rhizosphere function traits.This framework expands current perspectives on plant belowground functional traits,plant adaptation,and ecosystem stability under changing environments.
基金supported by the Czech Science Foundation (GACR 24-11954S)the Czech Academy of Sciences (RVO 67985939)。
文摘Understanding plant adaptive strategies that determine species distributions and ecological optima is crucial for predicting responses to global change drivers.While functional traits provide mechanistic insights into distribution patterns,the specific trait syndromes that best predict elevational optima,particularly in less-studied regions such as the Himalayas,remain unclear.This study employs a novel hierarchical framework integrating morphological,anatomical,and physiological traits to explain elevational distributions among 310 plant species across a 3,500-m gradient(2,650–6,150 m).We analyzed 95,000 floristic records collected from4,062 localities spanning 80,000 km^(2) in Ladakh,NW Himalayas,India,to define elevational optima and link them with 17 functional traits from over 7,800individuals.We assessed the roles of moisture and cold limitations on trait–optima relationships by comparing two contrasting habitats(dry steppe and wetter,colder alpine).The predictive power of functional traits was more pronounced in the alpine species facing more extreme abiotic stress than the steppe species.Our results indicate that conservative life history strategies strongly predict elevational optima in alpine areas,while drought avoidance and competitive dominance are key in steppe habitats.Trait syndromes combining short stature,compact growth forms,enhanced storage tissues,and features promoting water-use efficiency(δ13C),freezing resistance(fructan levels),and nutrient retention(high root nitrogen and leaf phosphorus) explained 61% of the variation in alpine species' optima.Conversely,lifespan and clonal propagation determined the optima of steppe species at lower elevations.The study emphasizes the importance of functional trait combinations in determining elevational optima,highlighting that alpine species prioritize resource conservation and stress tolerance,while steppe species focus on competitive growth strategies.This multi-trait approach contrasts with previous research focusing on single trait–elevation relationships,providing novel insights into the diverse mechanisms shaping elevational distributions and offering valuable predictive power for assessing vegetation responses to future climate change.
基金supported by the Major Science and Technology Project of Inner Mongolia Autonomous Region (2024JBGS0011-02)Foundation for Innovative Research Groups in Basic Research of Gansu Province (25JRRA490)+1 种基金Youth Innovation Promotion Association of the Chinese Academy of Sciences (2022437)National Natural Science Foundation of China (42207538)。
文摘Amid global climate change, rising levels of nitrogen(N) deposition have attracted considerable attention for their potential effects on the carbon cycle of terrestrial ecosystems. The desert steppes are a crucial yet vulnerable ecosystem in arid areas, but their response to the combination of N addition and precipitation(a crucial factor in arid areas) remains underexplored. This study systematically explored the impact of N addition and precipitation on net ecosystem exchange(NEE) in a desert steppe in northern China. Specifically, we conducted a 2-a experiment from 2022 to 2023 with eight N addition treatments in the Urat desert steppe of Inner Mongolia Autonomous Region, China, to examine changes in NEE and explore its driving factors. The structural equation model(SEM) and multiple regression model were applied to determine the relationship of NEE with plant community characteristics and soil physical-chemical properties. Statistical results showed that N addition has no significant effect on NEE.However, it has a significant impact on the functional traits of desert steppe plant communities. SEM results further revealed that N addition has no significant effect on NEE in the desert steppe, whereas annual precipitation can influence NEE variations. The multiple regression model analysis indicated that plant functional traits play an important role in explaining the changes in NEE, accounting for 62.15% of the variation in NEE. In addition, plant height, as an important plant functional trait indicator, shows stronger reliability in predicting the changes in NEE and becomes a more promising predictor. These findings provide valuable insights into the complex ecological mechanisms governing plant community responses to precipitation and nutrient availability in the arid desert steppes, contributing to the improved monitoring and prediction of desert steppe ecosystem responses to global climate change.
基金financially supported by the National Basic Research Program of China(2014CB138806)the Natural Science Fund Project of Inner Mongolia(2015ZD02)+2 种基金the International Science and Technology Cooperation Program of China(2013DFR30760)the National Scientific and Technical Support Program of China(2012BAD12B02)the Special Fund for Agro-scientific Research in the Public Interest(201303060)
文摘Mowing is an important land management practice for natural semi-arid regions. A growing body of empirical evidence shows that different mowing regimes affect the functioning of grassland ecosystems. However, the responses of plant functional traits to long-term mowing and their allometric scaling under long-term mowing are poorly understood. For a better understanding of the effects of mowing on grassland ecosystems, we analyzed the allometric traits of leaves and stems of Leymus chinensis （Trin.） Tzvel., a dominant grass species in eastern Eurasian temperate grassland, at different mowing intensities （no clipping, clipping once every two years, once a year and twice a year）. Experiments were conducted on plots established over a decade ago in a typical steppe of Xilinhot, Inner Mongolia, China. Results showed that most of the functional traits of L. chinensis decreased with the increased mowing intensity. The responses of leaves and stems to long-term mowing were asymmetric, in which leaf traits were more stable than stem traits. Also significant allometric relationships were found among most of the plant functional traits under the four mowing treatments. Sensitive traits of L. chinensis （e.g. leaf length and stem length） were primary indicators associated with aboveground biomass decline under high mowing intensity. In conclusion, the allometric growth of different functional traits of L. chinensis varies with different long-term mowing practices, which is likely to be a strategy used by the plant to adapt to the mowing disturbances.
基金funded by the National Key Research and Development Program(No.2017YFD0600904)the National Natural Science Foundation of China(No.31922055)+3 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_0913)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)funded by the China Scholarship Council(Grant No.202108320285)partially supported by the Horizon 2020 Research and Innovation Programme—European Commission‘BIOSPACE Monitoring Biodiversity from Space’project(Grant Agreement ID 834709,H2020-EU.1.1)。
文摘The diameter at breast height(DBH) of trees and stands is not only a widely used plant functional trait in ecology and biodiversity but also one of the most fundamental measurements in managing forests. However, systematically measuring the DBH of individual trees over large areas using conventional ground-based approaches is labour-intensive and costly. Here, we present an improved area-based approach to estimate plot-level tree DBH from airborne Li DAR data using the relationship between tree height and DBH, which is widely available for most forest types and many individual tree species. We first determined optimal functional forms for modelling heightDBH relationships using field-measured tree height and DBH. Then we estimated plot-level mean DBH by inverting the height-DBH relationships using the tree height predicted by Li DAR. Finally, we compared the predictive performance of our approach with a classical area-based method of DBH. The results showed that our approach significantly improved the prediction accuracy of tree DBH(R^(2)=0.85–0.90, rRMSE=9.57%–11.26%)compared to the classical area-based approach(R^(2)=0.80–0.83, rRMSE=11.98%–14.97%). Our study demonstrates the potential of using height-DBH relationships to improve the estimation of the plot-level DBH from airborne Li DAR data.
基金supported by the National Natural Science Foundation of China(31772652 and 31802113)China Scholarship Council(202006620065)。
文摘Grazing exerts a profound influence on both the plant diversity and productivity of grasslands,while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration.Moreover,besides altering the taxonomic diversity of plant communities,grazing can also affect their diversity of functional traits.However,we still poorly understand how grazing modifies the relationship between plant functional diversity(FD)and soil carbon sequestration in grassland ecosystems.Here,we conducted a grazing manipulation experiment to investigate the effects of different grazing regimes(no grazing,sheep grazing(SG)and cattle grazing(CG))on the relationships between plant FD and soil carbon sequestration in meadow and desert steppe.Our findings showed that different livestock species changed the relationships between plant FD and soil organic carbon(SOC)in the meadow steppe.SG decoupled the originally positive relationship between FD and SOC,whereas CG changed the relationship from positive to negative.In the desert steppe,both SG and CG strengthened the positive relationship between FD and SOC.Our study illuminates the considerable impact of livestock species on the intricate mechanisms of soil carbon sequestration,primarily mediated through the modulation of various measures of functional trait diversity.In ungrazed meadows and grazed deserts,maintaining high plant FD is conducive to soil carbon sequestration,whereas in grazed meadows and ungrazed deserts,this relationship may disappear or even reverse.By measuring the traits and controlling the grazing activities,we can accurately predict the carbon sequestration potential in grassland ecosystems.
基金supported by the Ontario Centres of Excellence,Nipissing University Internal Research FundOntario/Baden-Württemberg Student Exchange Programthe Ontario/Baden-Württemberg Faculty Research Exchange
文摘Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger;however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.
基金supported by the National Natural Science Foundation of China(32001165,41473068)the Natural Science Foundation of Sichuan Province(2022NSFSC1753)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA26040202)the Free Exploration Project of the Dual Support Plan for Disciplinary Development of Sichuan Agricultural University(2024ZYTS016).
文摘As a key functional trait affecting many physiological processes,leaf pH is closely related to other leaf traits at the local scale.Nevertheless,whether and how leaf pH is linked with other leaf functional traits across geographic scales remains unclear.A field survey in northern China was conducted to investigate the relationships between leaf pH and some key leaf structural(specific leaf area,SLA;leaf dry matter content,LDMC)and chemical traits(elemental concentrations;total dissolved solids,TDS;practical salinity),as well as the effects of environmental factors on these relationships.Our results showed that the trait coordination may vary in degree or direction across eco-geographic regions(arid vs.non-arid regions)and life-forms(woody vs.herbaceous plants).Generally,leaf pH was negatively related to SLA,but positively related to TDS and salinity.However,leaf pH and LDMC were negatively correlated in arid regions but positively correlated in non-arid regions;leaf pH covaried with N(similarly,with Ca,Mg and Na)in the same direction for both herbaceous and woody plants in arid regions,but not in non-arid regions.Climatic factors mainly influenced the relationships of leaf pH with leaf Ca and Fe concentrations,while soil factors mostly affected those with leaf P,Ca and Mn concentrations.Our findings highlight the divergent coordination between leaf pH and other leaf traits across life-forms and eco-geographic regions and may shed light on the in-depth understanding of the role of acid-base balance in plant eco-physiological processes and ecological adaptation over biogeographic scales.
基金supported by the National Natural Science Foundation of China(Nos.32360380,32360278)the Guizhou Provincial Key Technology R&D Program(General[2023]111)the Basic Research Program in Guizhou Province(ZK[2022]General 098,ZK[2022]General 036,ZK[2022]General 079).
文摘The interspecific variations of plant functional traits can characterize the niche positions of species within communities,while the intraspecific variations can accurately display the species’niche breadth.Revealing relative contributions of intra-and interspecific variations to plant functional community structure is crucial in understanding how the species coexist together,especially in species-diverse ecosystems.To explore how the intra-and interspecific variations of plant functional traits change along the successional pathway in heterogeneous conditions,we established a series of plots and measured main plant functional traits along the natural regeneration in karst forest ecosystems.By quantifying the intra-and interspecific variations of plant functional traits,we found that the changes in intraspecific variations were relatively lower compared to changes in interspecific variations throughout the natural regeneration.Further analysis showed that the community spatial structure contributed more to the intraspecific variations of plant functional traits,while the soil physicochemical properties contributed more to interspecific variations.Our study suggested that tree species might tend to narrow their niche and change the positions to release the niche overlap when faced with heterogeneous habitat conditions.
基金the National Science Foundation of China(41871040)the Second Tibetan Plateau Scientific Expedition and Research(2019QZKK0405)Joint Research Project of Three-River-Resource National Park funded by the Chinese Academy of Sciences and Qinghai Provincial People's Government(LHZX-2020-08).
文摘A better understanding the mechanisms driving plant biomass allocation in different ecosystems is an important theoretical basis for ilustrating the adaptive strategies of plants.To date,the effects of habitat conditions on plant biomass allocation have been widely studied.However,it is less known how plant community traits and functions(PCTF)affect biomass allocation,particularly in alpine grassland ecosystems.In this study,community-weighted means(CWM)were calculated at the community level using five leaf functional traits,and the relationships between PCTF and biomass trade-offs were explored using correlation analysis,variation partitioning analysis and structural equation modeling.We found that the trade-off values were greater than zero in both alpine meadow(AM)and alpine steppe(AS)across the Tibetan Plateau,with different values of 0.203 and 0.088 for AM and AS,respectively.Moreover,the critical factors determining biomass allocation in AS were species richness(SR;scored at 0.69)and leaf dry matter content of CWM(CWM_(LDMC),scored at 0.42),while in AM,the key factors were leaf dry matter content(CWM.pMC scored at 0.48)and leaf carbon content of CWM(CWM_(LC),scored at-0.45).In particular,both CWM_(LDMC)and SR in AS,as well as CWM_(LDMC)and CWM_(LDMC)in AM were primarily regulated by precipitation.In summary,precipitation tends to drive biomass allocation in alpine grasslands through its effects on PCTF,hence highlighting the importance of PCTF in regulating plant biomass allocation strategies along precipitation gradients.
基金supported by the National Key Research and Development Program of China(no.2016YFC0501602)International Partnership Program(no.121311KYSB20170004)of Chinese Academy of Sciences.
文摘Aims Accurate prediction of spatiotemporal variations in carbon and water fluxes of heterogeneous landscape is critical to comprehensively address the effects of climate change and vegetation dynamics on landscape and regional carbon and water cycling.Methods A field study was conducted to characterize the seasonal variations in gas fluxes and explore their relationships with abiotic and biotic factors in a small grassland landscape.Daytime carbon and water fluxes including net ecosystem exchange,gross ecosystem productivity,ecosystem respiration and evapotranspiration(ET)were measured for three types of grassland patches over a growing season using the closed chamber method.The key plant trait variables were measured,based on which community weighted mean(CWM)and functional variance(FDvar)were calculated.Important Findings The results showed that the temporal variations in the carbon and water fluxes were regulated by meteorological,soil and community functional variables.Inclusion of the CWM and FDvar of plant trait measures greatly improved the degree of explanation of the predict models.Specific leaf area and leafδ^(13)C content(Lδ^(13)C)were the most important trait variables in affecting the variations of the gas fluxes.CWMs indices had greater importance than FDvar indices in predicting the variation of the C fluxes but FDvar indices were more important for ET than C fluxes.Our findings demonstrated that mass ratio hypothesis and the complementary effects hypothesis are not mutually exclusive but have different relative importance for different ecosystem processes.Community functional traits played important roles in predicting the spatiotemporal variations of carbon and water fluxes in semiarid grassland.
基金A.K.B.was supported by the Faculty of Science and Technology,Aarhus University(2008-218/5-24)Augustinus’Foundation(11-0677)+4 种基金Oticon(11-0565)Niels Bohr Foundation and Aarhus Universitets Forsknings Fond(AUFFF2011-FLS330)J.-C.S.was supported by the European Research Council(ERC-2012-StG-310886-HISTFUNC)Additionally,we also consider this article a contribution of Center for Informatics Research on Complexity in Ecology(CIRCE)funded by Aarhus University and Aarhus University Research Foundation under the AU IDEAS program.
文摘Aims Studies integrating phylogenetic history and large-scale community assembly are few,and many questions remain unanswered.Here,we use a global coastal dune plant data set to uncover the important factors in community assembly across scales from the local filtering processes to the global long-term diversification and dispersal dynamics.Coastal dune plant communities occur worldwide under a wide range of climatic and geologic conditions as well as in all biogeographic regions.However,global patterns in the phylogenetic composition of coastal dune plant communities have not previously been studied.Methods The data set comprised vegetation data from 18463 plots in New Zealand,South Africa,South America,North America and Europe.The phylogenetic tree comprised 2241 plant species from 149 families.We calculated phylogenetic clustering(Net Relatedness Index,NRI,and Nearest Taxon Index,NTI)of regional dune floras to estimate the amount of in situ diversification relative to the global dune species pool and evaluated the relative importance of land and climate barriers for these diversification patterns by geographic analyses of phylogenetic similarity.We then tested whether dune plant communities exhibit similar patterns of phylogenetic structure within regions.Finally,we calculated NRI for local communities relative to the regional species pool and tested for an association with functional traits(plant height and seed mass)thought to vary along sea–inland gradients.Important Findings Regional species pools were phylogenetically clustered relative to the global pool,indicating regional diversification.NTI showed stronger clustering than NRI pointing to the importance of especially recent diversifications within regions.The species pools grouped phylogenetically into two clusters on either side of the tropics suggesting greater dispersal rates within hemispheres than between hemispheres.Local NRI plot values confirmed that most communities were also phylogenetically clustered within regions.NRI values decreased with increasing plant height and seed mass,indicating greater phylogenetic clustering in communities with short maximum height and good dispersers prone to wind and tidal disturbance as well as salt spray,consistent with environmental filtering along sea–inland gradients.Height and seed mass both showed significant phylogenetic signal,and NRI tended to correlate negatively with both at the plot level.Low NRI plots tended to represent coastal scrub and forest,whereas high NRI plots tended to represent herb-dominated vegetation.We conclude that regional diversification processes play a role in dune plant community assembly,with convergence in local phylogenetic community structure and local variation in community structure probably reflecting consistent coastal-inland gradients.Our study contributes to a better understanding of the globally distributed dynamic coastal ecosystems and the structuring factors working on dune plant communities across spatial scales and regions.
基金supported by the‘Strategic Priority Research Program’of the Chinese Academy of Sciences(XDA26040202)the National Natural Science Foundation of China(32001165)supported by Chinese Universities Scientifc Fund(2021TC117).
文摘To compare current methods of pretreatment/determination for plant foliar pH,we proposed a method for longperiod sample preservation with little interference with the stability of foliar pH.Four hundred leaf samples from 20 species were collected and four methods of pH determination were used:refrigerated(stored at 4°C for 4 days),frozen(stored at−16°C for 4 days),oven-dried and fresh green-leaf pH(control).To explore the effects of different leaf:water mixing ratio on the pH determination results,we measured oven-dried green-leaf pH by leaf:water volume ratio of 1:8 and mass ratio of 1:10,and measured frozen senesced-leaf pH by mass ratio of 1:10 and 1:15.The standard major axis regression was used to analyze the relationship and the conversion equation between the measured pH with different methods.Foliar pH of refrigerated and frozen green leaves did not signifcantly differ from that of fresh green-leaf,but drying always overrated fresh green-leaf pH.During the feld sampling,cryopreservation with a portable refrigerator was an advisable choice to get a precise pH.For long-duration feld sampling,freezing was the optimal choice,and refrigeration is the best choice for the shorttime preservation.The different leaf:water mixing ratio signifcantly infuenced the measured foliar pH.High dilution reduced the proton concentration and increased the measured pH.Our fndings provide the conversion relationships between the existing pretreatment and measurement methods,and establish a connection among pH determined by different methods.Our study can facilitate foliar pH measurement,thus contributing to understanding of this interesting plant functional trait.
文摘Aims Community assembly persists as a key topic in ecology due to the complex variation in the relative importance of assembly forces and mechanisms across spatio-temporal scales and eco-systems.Here we address a forest-savanna vegetation mosaic in the Brazilian Atlantic forest to examine the role played by soil attributes as determinants of community assembly and organiza-tion at a landscape spatial scale.Methods We examined soil and plant assemblage attributes across 23 plots of forest and savanna in a 1600 km2 landscape exposed to the same climatic conditions in the Atlantic forest region of northeast Brazil.Assemblage attributes included species richness,taxonomic and functional composition(community weighted mean,CWM)and functional diversity(quadratic diversity;Rao’s quadratic entropy index)relative to plant leaf area,specific leaf area,leaf dry matter content,thickness and succulence.Important Findings Our results suggest that forest and savanna patches exposed to the same climatic conditions clearly differ in terms of soil attributes,plant assemblage structure,taxonomic and functional composition.By selecting particular plant strategies relative to resource economy,soil potentially affects community structure,with forest assemblages bear-ing more acquisitive resource-use strategies,while conservative plant strategies are more frequent in savannas.Accordingly,savanna-forest mosaics in the Atlantic forest region represent spatially organized plant assemblages in terms of taxonomic and functional features,with a sig-nal of trait convergence in both vegetation types.Soil-mediated filter-ing thus emerges as a potential deterministic assembly force affecting the spatial organization of savanna-forest boundaries and mosaics.
