Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology,because answers to these questions depend on the analytical types,dimensions,and components of beta div...Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology,because answers to these questions depend on the analytical types,dimensions,and components of beta diversity we concerned.To obtain a comprehensive understanding of assemblage dissimilarity and its implications for biodiversity conservation in the Himalayas,we explored the elevational patterns and determinants of beta diversity and its turnover and nestedness components of pairwise and multiple types and taxonomic and phylogenetic dimensions simultaneously.Patterns of beta diversity and their components of different types and dimensions were calculated based on 96 sampling quadrats along an 1800-5400 m elevational gradient.We examined whether and how these patterns differed from random expectations using null models.Furthermore,we used random forest methods to quantify the role of environmental variables representing climate,topography,and human disturbance in determining these patterns.We found that beta diversity and its turnover component,regardless of its types and dimensions,shown a hump-shaped elevational patterns.Both pairwise and multiple phylogenetic beta diversity were remarkably lower than their taxonomic counterpart.These patterns were significantly less than random expectation and were mostly associated with climate variables.In summary,our results suggested that assemblage dissimilarity of seed plants was mostly originate from the replacement of closely related species determined by climate-driven environmental filtering.Accordingly,conservation efforts should better cover elevations with different climate types to maximalize biodiversity conservation,rather than only focus on elevations with highest species richness.Our study demonstrated that comparisons of beta diversity of different types,dimensions,and components could be conductive to consensus on the origin and mechanism of assemblage dissimilarity.展开更多
Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain unc...Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain uncertain in arid mountain ecosystems,where climosequences are quite different from other ecosystems.To address this gap,this study investigated the distribution determinants of microbial communities,C cycling-related genes,and SOC fractions along an elevational gradient(1707–3548 m),with a mean annual precipitation(MAP)range of 38 to 344 mm,on the north slope of the central part of the Kunlun Mountains,China using a metagenomic approach.The results showed that elevation significantly influenced the α-diversity(Shannon index)and composition of microbial communities as well as the C cycling-related genes.The α-diversities of microbial taxa and C cycling-related genes linearly increased with the increase in MAP along the elevational gradient.The elevational patterns of the genes encoding glycoside hydrolases and glycosyl transferases(GTs)were mainly driven by soil electrical conductivity(EC),mean annual temperature(MAT),MAP,and plant diversity.Furthermore,mineral-associated organic C(MAOC),particulate organic C(POC),and their sum generally increased with elevation.However,the MAOC/POC ratio followed a unimodal pattern,suggesting greater stability of the SOC pool in the mid-elevation regions.This unimodal pattern was likely influenced by the abundances of Actinobacteria and the genes encoding GTs and carbohydrate esterases and the threshold effects of soil EC and MAT.In summary,our findings indicate that the distribution patterns of microbial communities and C cycling-related genes along the elevational gradient in an arid ecosystem are distinct from those in the regions with higher MAP,facilitating the prediction of climate change effects on SOC metabolism under more arid conditions.Soil salinity,plant diversity,precipitation,and temperature are the main regulatory factors of microbial C metabolism processes,and they potentially play a central role in mediating SOC pool stability.展开更多
Allium stracheyi(Baker)is widely utilized as a culinary herb and is typically encountered in the higher elevations of the Himalayas.Consequently,it is of great significance to compare the ecological adaptability of th...Allium stracheyi(Baker)is widely utilized as a culinary herb and is typically encountered in the higher elevations of the Himalayas.Consequently,it is of great significance to compare the ecological adaptability of this indigenous species to alternative habitats and its introduction into new environments.This research aims to investigate and gain a comprehensive understanding of A.stracheyi,also known as faran,in Uttarakhand region.We aim to examine how this plant adapts morphologically,physiologically,biochemically,and anatomically to varying elevations,specifically at 550,2200,2460,and 3400 m above mean sea level(m AMSL).This plant demonstrated remarkable morphophysiological adjustments across various aspects of its development,encompassing modified growth patterns,alterations in leaf dimensions,leaf count,etc..Moreover,biochemical adaptations have been identified as pivotal in bolstering the plant resilience to the stress associated with higher elevation.Enzymes like superoxide dismutase(SOD)and peroxidase(POD)exhibited significant responsiveness to elevational variations,contributing to the plant's ability to confront the challenges posed by high-elevational conditions.In terms of anatomy,the plant manifested alterations in its leaf and vascular tissues along the elevational gradient.These modifications involve an increased density of stomata and a greater count of vascular bundles,optimizing gas exchange and adaptation to water stress in frequently encountered harsh environmental conditions at higher elevations.Understanding the adaptive mechanisms employed by A.stracheyi provides valuable insights,especially in forecasting how A.stracheyi might respond to global climate change,particularly in regions affected by habitat fragmentation.展开更多
Much of the world's biodiversity lies in heterogeneous mountain areas with their diverse environments.As an example,Iranian montane ranges are highly diverse,particularly in the Irano-Turanian phytogeographical re...Much of the world's biodiversity lies in heterogeneous mountain areas with their diverse environments.As an example,Iranian montane ranges are highly diverse,particularly in the Irano-Turanian phytogeographical region.Understanding plant diversity patterns with increasing elevation is of high significance,not least for conservation planning.We studied the pattern of species richness,Shannon diversity,endemic richness,endemics ratio,and richness of life forms along a 3900 m elevational transect in Mount Palvar,overlooking the Lut Desert in Southeast Iran.We also analyzed the effect of environmental variables on species turnover along the vertical gradient.A total of 120 vegetation plots(10 m×10 m)were sampled along the elevational transect containing species and environmental data.To discover plant diversity pattern along the elevational gradient,generalized additive model(GAM)was used.Non-metric multidimensional scaling(NMDS)was applied for illustrating the correlation between species composition and environmental variables.We found hump-shaped pattern for species richness,Shannon diversity,endemic richness,and species richness of different life forms,but a monotonic increasing pattern for ratio of endemic species from low to high elevations.Our study confirms the humped pattern of species richness peaking at intermediate elevations along a complete elevational gradient in a semi-arid mountain.The monotonic increase of endemics ratio with elevation in our area as a case study is consistent with global increase of endemism with elevation.According to our results,temperature and precipitation are two important climatic variables that drive elevational plant diversity,particularly in seasonally dry areas.Our study suggests that effective conservation and management are needed for this low latitude mountain area along with calling for long-term monitoring for species redistribution.展开更多
Reproductive strategies of sexually dimorphic plants vary in response to the environment.Here,we ask whether the sexual systems of Fagopyrum species(i.e.,selfing homostylous and out-crossing distylous)represent distin...Reproductive strategies of sexually dimorphic plants vary in response to the environment.Here,we ask whether the sexual systems of Fagopyrum species(i.e.,selfing homostylous and out-crossing distylous)represent distinct adaptive strategies to increase reproductive success in changing alpine environments.To answer this question,we determined how spatial and temporal factors(e.g.,elevation and peak flowering time)affect reproductive success(i.e.,stigmatic pollen load)in nine wild Fagopyrum species(seven distylous and two homostylous)among 28 populations along an elevation gradient of 1299-3315 m in the Hengduan Mountains,southwestern China.We also observed pollinators and conducted hundreds of hand pollinations to investigate inter/intra-morph compatibility,self-compatibility and pollen limitation in four Fagopyrum species(two distylous and two homostylous).We found that Fagopyrum species at higher elevation generally had bigger flowers and more stigmatic pollen loads;lateflowering individuals had smaller flowers and lower pollen deposition.Stigmatic pollen deposition was more variable in distylous species than in homostylous species.Although seed set was not pollenlimited in all species,we found that fruit set was much lower in distylous species,which rely on frequent pollinator visits,than in homostylous species capable of autonomous self-pollination.Our findings that pollination success increases at high elevations and decreases during the flowering season suggest that distylous and homostylous species have spatially and temporally distinct reproductive strategies related to environment-dependent pollinator activity.展开更多
Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradient...Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.展开更多
Acidobacteria is one of the most dominant and abundant phyla in soil,and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational d...Acidobacteria is one of the most dominant and abundant phyla in soil,and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational diversity patterns. We selected four elevation gradients from 1000 to 2800 m with typical vegetation types of the northern slope of Shennongjia Mountain in central China. The vegetation types were evergreen broadleaved forest,deciduous broadleaved forest,coniferous forest and sub-alpine shrubs. We analyzed the soil acidobacterial community composition,elevational patterns and the relationship between Acidobacteria subdivisions and soil enzyme activities by using the 16 S rRNA meta-sequencing technique and multivariate statistical analysis. The result found that 19 known subdivisions as well as an unclassified phylotype were presented in these forest sites,and Subdivision 6 has the highest number of detectable operational taxonomic units（OTUs）. A significant single peak distribution pattern（P 〈 0.05） between the OTU number and the elevation was observed. The Jaccard and Bray–Curtis index analysis showed that the soil Acidobacteria compositional similarity significantly decreased（P 〈 0.01） with the increase in elevation distance. Mantel test analysis showed the most of the soil Acidobacteria subdivisions had the significant relationship（P 〈 0.01） with different soil enzymes. Therefore,soil Acidobacteria may be involved in different ecosystem functions in global elemental cycles. Partial Mantel tests and CCA analysis showed that soil pH,soil temperature and plant diversity may be the key factors in shaping the soil Acidobacterial community structure.展开更多
Temperature and freeze-thaw events are two key factors controlling litter decomposition in cold biomes.Predicted global warming and changes in freeze-thaw cycles therefore may directly or indirectly impact litter deco...Temperature and freeze-thaw events are two key factors controlling litter decomposition in cold biomes.Predicted global warming and changes in freeze-thaw cycles therefore may directly or indirectly impact litter decomposition in those ecosystems. Here, we conducted a2-year-long litter decomposition experiment along an elevational gradient from 3000 to 3600 m to determine the potential effects of litter quality, climate warming and freeze-thaw on the mass losses of three litter types [dragon spruce（Picea asperata Mast.）, red birch（Betula albosinensis Burk.）, and minjiang fir（Abies faxoniana Rehd. et Wild）]. Marked differences in mass loss were observed among the litter types and sampling dates. Decay constant（k） values of red birch were significantly higher than those of the needle litters. However, mass losses between elevations did not differ significantly for any litter type.During the winter, lost mass contributed 18.3-28.8 % of the net loss rates of the first year. Statistical analysis showed that the relationships between mass loss and litter chemistry or their ratios varied with decomposition periods. Our results indicated that short-term field incubations could overestimate the k value of litter decomposition.Considerable mass was lost from subalpine forest litters during the wintertime. Potential future warming may not affect the litter decomposition in the subalpine forest ecosystems of eastern Tibetan Plateau.展开更多
Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study,...Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.展开更多
Mountain systems harbor an evolutionarily unique and exceptionally rich biodiversity,especially for amphibians.However,the associated elevational gradients and underlying mechanisms of amphibian diversity in most moun...Mountain systems harbor an evolutionarily unique and exceptionally rich biodiversity,especially for amphibians.However,the associated elevational gradients and underlying mechanisms of amphibian diversity in most mountain systems remain poorly understood.Here,we explored amphibian phylogenetic and functional diversity along a 2600 m elevational gradient on Mount Emei on the eastern margin of the Qinghai-Tibetan Plateau in southwestern China.We also assessed the relative importance of spatial(area)and environmental factors(temperature,precipitation,solar radiation,normalized difference vegetation index,and potential evapotranspiration)in shaping amphibian distribution and community structure.Results showed that the phylogenetic and functional diversities were unimodal with elevation,while the standardized effect size of phylogenetic and functional diversity increased linearly with elevation.Phylogenetic net relatedness,nearest taxon index,and functional net relatedness index all showed a positive to negative trend with elevation,indicating a shift from clustering to overdispersion and suggesting a potential change in key processes from environmental filtering to competitive exclusion.Overall,our results illustrate the importance of deterministic processes in structuring amphibian communities in subtropical mountains,with the dominant role potentially switching with elevation.This study provides insights into the underlying assembly mechanisms of mountain amphibians,integrating multidimensional diversity.展开更多
Understanding the vertical distribution patterns of soil microbial community and its driving factors in alpine grasslands in the humid regions of the Tibet Plateau might be of great significance for predicting the soi...Understanding the vertical distribution patterns of soil microbial community and its driving factors in alpine grasslands in the humid regions of the Tibet Plateau might be of great significance for predicting the soil microbial community of this type of vegetation in response to environmental change. Using phospholipid fatty acids （PLFA）, we investigated soil microbial community composition along an elevational gradient （3094-4131 m above sea level） on Mount Yajiageng, and we explored the impact of plant functional groups and soil chemistry on the soil microbial community. Except for Arbuscular Mycorrhizal fungi （AM fungi） biomarker 18：2ω6,9 increasing significantly, other biomarkers did not show a consistent trend with the elevational gradient. Microbial biomass quantified by total PLFAs did not show the elevational trend and had mean values ranging from 1.64 to 4.09 ktmol per g organic carbon （OC）, which had the maximum value at the highest site. Bacterial PLFAs exhibited a similar trend with total PLFAs, and its mean values ranged from 0.82 to 1.81 μmol （g OC）-1. The bacterial to fungal biomass ratios had the minimum value at the highest site, which might be related to temperature and soil total nitrogen （TN）. The ratios of Gram-negative to Gram-positive bacteria had a significantly negative correlation with soil TN and had the maximum value at the highest site. Leguminous plant coverage and soil TN explained 58% of the total variation in the soil microbial community and could achieve the same interpretation as the whole model. Other factors may influence the soil microbial community through interaction with leguminous plant coverage and soil TN. Soil chemistry and plant functional group composition in substantial amounts explained different parts of the variation within the soil microbial community, and the interaction between them had no impact on the soil microbial community maybe beeause long-term grazing greatly reduces litter. In sum, although there were obvious differences in soil microbial communities along the elevation gradient, there were no clear elevational trends found in general. Plant functional groups and soil chemistry respectively affect the different aspects of soil microbial community. Leguminous plant coverage and soil TN had important effects in shaping soil microbial community.展开更多
Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-c...Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-climate interactions is vital for mountainous ecosystems. Water-use efficiency （WUE） provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands. This paper explored net primary productivity （NPP） and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin （TMJB）, Xinjiang of China, using the Biome-BGC model. The results showed that： 1 ） the NPP increased by 0.05 g C/（m2-a） with every increase of 1-m elevation, reached the maximum at the mid-high elevation （1,600 m asl）, and then decreased by 0.06 g C/（m2.a） per 1-m increase in elevation; 2） the grassland NPP was positively correlated with temperature in alpine meadow （AM, 2,700-3,500 m asl）, mid-mountain forest meadow （MMFM, 1,650-2,700 m asl） and low-mountain dry grassland （LMDG, 650-1,650 m asl）, while positive correlations were found between NPP and annual precipitation in plain desert grassland （PDG, lower than 650 m asl）; 3） an increase （from 0.08 to 1.09 g C/（m2.a）） in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009; and 4） remarkable differences in WUE were found among different elevations, in general, WUE increased with decreasing elevation, because water availability is lower at lower elevations; however, at elevations lower than 540 m asl, we did observe a decreasing trend of WUE with decreasing elevation, which may be due to the sharp changes in canopy cover over this gradient. Our research suggests that the NPP simulated by Biome-BGC is consistent with field data, and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity.展开更多
Gene flow and demographic history can play important roles in the adaptive genetic differentiation of species, which is rarely understood in the high-altitude adaptive evolution of birds. To elucidate genetic divergen...Gene flow and demographic history can play important roles in the adaptive genetic differentiation of species, which is rarely understood in the high-altitude adaptive evolution of birds. To elucidate genetic divergence of populations in the great tit complex （Parus major, P. minor and P. cinereus） at different elevations, we compared the genetic structure and gene flow in hemoglobin genes with neutral loci. Our results revealed the elevationally divergent structure of αA-globin gene, distinctive from that of the/βA-globin gene and neutral loci. We further investigated gene flow patterns among the populations in the central-northern （〉 1,000 m a.s.l.）, south-eastern （〈 1,000 m a.s.l.） regions and the Southwest Mountains （〉2,000 m a.s.l.） in China. The high-altitude （〉 1,000 m a.s.l.） diverged aA-globin genetic structure coincidαed with higher αA-globin gene flow between highland populations, in contrast to restricted neutral gene flow concordant with the phylogeny. The higher aA-globin gene flow suggests the possibility of adaptive evolution during population divergence, contrary to the lower aA-globin gene flow homogenized by neutral loci during population expantion. In concordance with patterns of historical gene flow, genotypic and allelic profiles provide distinctive patterns of fixation in different high-altitude populations. The fixation of alleles at contrasting elevations may primarily due to highland standing variants aA49Asn/72Asn/108Ala originating from the south-western population. Our findings demonstrate a pattern of genetic divergence with gene flow in major hemoglobin genes depending on population demographic history.展开更多
Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because...Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because patterns of elevational diversity can vary among lineages and mountain systems it remains difficult to extrapolate findings from one montane region to another,or among lineages.In this study,we assessed patterns and drivers of avian diversity along an elevational gradient on the eastern slope of Mt.Gongga,the highest peak in the Hengduan Mountain Range in central China,and a mountain where comprehensive studies of avian diversity are still lacking.Methods:We surveyed bird species in eight 400-m elevational bands from 1200 to 4400 m a.s.l.between 2012 and 2017.To test the relationship between bird species richness and environmental factors,we examined the relative importance of seven ecological variables on breeding season distribution patterns:land area(LA),mean daily temperature(MDT),seasonal temperature range(STR),the mid-domain effect(MDE),seasonal precipitation(SP),invertebrate biomass(IB) and enhanced vegetation index(EVI).Climate data were obtained from five local meteorological stations and three temperature/relative humidity smart sensors in 2016.Results:A total of 219 bird species were recorded in the field,of which 204 were recorded during the breeding season(April–August).Species richness curves(calculated separately for total species,large-ranged species,and smallranged species) were all hump-shaped.Large-ranged species contributed more to the total species richness pattern than small-ranged species.EVI and IB were positively correlated with total species richness and small-ranged species richness.LA and MDT were positively correlated with small-ranged species richness,while STR and SP were negatively correlated with small-ranged species richness.MDE was positively correlated with large-ranged species richness.When we considered the combination of candidate factors using multiple regression models and model-averaging,total species richness and large-ranged species richness were correlated with STR(negative) and MDE(positive),while small-ranged species richness was correlated with STR(negative) and IB(positive).Conclusions:Although no single key factor or suite of factors could explain patterns of diversity,we found that MDE,IB and STR play important but varying roles in shaping the elevational richness patterns of different bird species categories.Model-averaging indicates that small-ranged species appear to be mostly influenced by IB,as opposed to large-ranged species,which exhibit patterns more consistent with the MDE model.Our data also indicate that the species richness varied between seasons,offering a promising direction for future work.展开更多
Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration.Although soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients i...Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration.Although soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients in different climatic zones is still unknown. This paper investigates seed density,species composition and nonconstituent species of forest soil seed banks in Yunnan Province, southwest China. Similarity between the soil seed bank and standing vegetation was also examined. We collected soil samples from sites spanning 12 elevations in tropical rain forests, subtropical evergreen broadleaved forests and subalpine coniferous forests, and transported them to a glasshouse for germination trials for species identification. The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests. Seeds of woody species dominated the soil seed banks of tropical and subtropical forests, while herbs dominated those of subalpine forests.The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests, followed by subtropical forests but were completely absent from subalpine forests.展开更多
Elevational patterns of trait occurrence and functional diversity provide an important perspective for understanding biodiversity.However,previous studies have mostly examined functional diversity at the community sca...Elevational patterns of trait occurrence and functional diversity provide an important perspective for understanding biodiversity.However,previous studies have mostly examined functional diversity at the community scale.Here,we examined large-scale patterns of trait occurrence and functional diversity in Delphinium along an elevational gradient from 1000 to 5700 m in the Hengduan Mountains,SW China.Elevational distribution and trait data of 102 Delphinium species were compiled to evaluate the patterns of interspecific traits,species richness,and functional diversity.We found that the distribution of species richness showed a unimodal curve that peaked between 3500 and 4000 m;functional diversity and traits showed different patterns along an elevational gradient The functional diversity increased at a lower rate along an elevation gradient,whereas species richness continued to increase.Species with large ranges and non-endemic species were most affected by geometric constraints.Richness of species endemic to the Hengduan Mountains peaked at higher elevations,likely due to increased speciation and restricted dispersion under alpine conditions.We conclude that the middle elevation region is not only the functionally richest but also the most functionally stable region for Delphinium,which could be insurance against environmental change.Extreme conditions and strong environmental filters in an alpine environment may cause the convergence of species traits,which could relate to reducing nutrient trait investment and increasing reproductive trait investment.We conclude that large-scale studies are consistent with previous studies at the community scale.This may indicate that the relationship between functional diversity and species richness across different scales is the same.展开更多
Identifying how reproductive strategies such as the trade-off between clutch size versus egg mass vary with elevational gradients is essential for our understanding of life-history evolution.We studied lacertid lizard...Identifying how reproductive strategies such as the trade-off between clutch size versus egg mass vary with elevational gradients is essential for our understanding of life-history evolution.We studied lacertid lizards(Eremias argus)in China,from six populations at different altitudes,to assess elevational variation in reproductive strategy.We found significant between-population variation in maternal body size and clutch mass,but these variations were not explained by elevational differences.However,high-elevation females tended to produce smaller clutches of larger eggs compared with their low-elevation counterparts,demonstrating an elevational change in the trade-off between egg size and number.The egg size-number trade-off is a reproductive strategy that may favor large offspring,better enabling them to survive severe and unpredictable environments found at high elevations.展开更多
In mountain ecosystems,plants are sensitive to climate changes,and an entire range of species distribution can be observed in a small area.Therefore,mountains are of great interest for climate–growth relationship ana...In mountain ecosystems,plants are sensitive to climate changes,and an entire range of species distribution can be observed in a small area.Therefore,mountains are of great interest for climate–growth relationship analysis.In this study,the Siberian spruce’s(Picea obovata Ledeb.)radial growth and its climatic response were investigated in the Western Sayan Mountains,near the SayanoShushenskoe Reservoir.Sampling was performed at three sites along an elevational gradient:at the lower border of the species range,in the middle,and at the treeline.Divergence of growth trends between individual trees was observed at each site,with microsite landscape-soil conditions as the most probable driver of this phenomenon.Cluster analysis of individual tree-ring width series based on inter-serial correlation was carried out,resulting in two sub-set chronologies being developed for each site.These chronologies appear to have substantial differences in their climatic responses,mainly during the cold season.This response was not constant due to regional climatic change and the local influence of the nearby Sayano-Shushenskoe Reservoir.The main response of spruce to growing season conditions has a typical elevational pattern expected in mountains:impact of temperature shifts with elevation from positive to negative,and impact of precipitation shifts in the opposite direction.Chronologies of trees,growing under more severe micro-conditions,are very sensitive to temperature during September–April and to precipitation during October–December,and they record both inter-annual and long-term climatic variation.Consequently,it would be interesting to test if they indicate the Siberian High anticyclone,which is the main driver of these climatic factors.展开更多
It remains unclear whether the elevational diversity gradients observed in seed plants across different taxonomic levels （family, genus, and species） are driven by the same macro-environmental variables. In this stu...It remains unclear whether the elevational diversity gradients observed in seed plants across different taxonomic levels （family, genus, and species） are driven by the same macro-environmental variables. In this study, seed plant elevational distribution data from the Lancang River Nature Reserve （Yunnan, China） were used to investigate spatial patterns in diversity and their environ- mental correlates, comparing across taxonomic levels. Environmental variables included energy availability, climate seasonality and environmental heterogeneity. All taxonomic levels （family, genus, and species） were found to have strong elevational richness gradients, with the strength of the gradient weakening at higher taxonomic levels. Spatial patterns in richness were explained by a combination of contemporary environmental variables and the mid-domain effect at all taxonomic levels. The independent effects of temperature- and precipitation-related variables were similar in explaining geographical patterns of family, genus and species richness. Energy, seasonality and heterogeneity variables influenced seed plant spatial richness at different taxonomic levels in similar ways.展开更多
基金supported by the National Natural Science Foundation of China(grant number 31901109)Guangdong Basic and Applied Basic Research Foundation(grant number 2021A1515110744).
文摘Understanding how and why assemblage dissimilarity changes along spatial gradient is a great challenge in ecology,because answers to these questions depend on the analytical types,dimensions,and components of beta diversity we concerned.To obtain a comprehensive understanding of assemblage dissimilarity and its implications for biodiversity conservation in the Himalayas,we explored the elevational patterns and determinants of beta diversity and its turnover and nestedness components of pairwise and multiple types and taxonomic and phylogenetic dimensions simultaneously.Patterns of beta diversity and their components of different types and dimensions were calculated based on 96 sampling quadrats along an 1800-5400 m elevational gradient.We examined whether and how these patterns differed from random expectations using null models.Furthermore,we used random forest methods to quantify the role of environmental variables representing climate,topography,and human disturbance in determining these patterns.We found that beta diversity and its turnover component,regardless of its types and dimensions,shown a hump-shaped elevational patterns.Both pairwise and multiple phylogenetic beta diversity were remarkably lower than their taxonomic counterpart.These patterns were significantly less than random expectation and were mostly associated with climate variables.In summary,our results suggested that assemblage dissimilarity of seed plants was mostly originate from the replacement of closely related species determined by climate-driven environmental filtering.Accordingly,conservation efforts should better cover elevations with different climate types to maximalize biodiversity conservation,rather than only focus on elevations with highest species richness.Our study demonstrated that comparisons of beta diversity of different types,dimensions,and components could be conductive to consensus on the origin and mechanism of assemblage dissimilarity.
基金sponsored by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(No.2022D01B213)the Key Scientific and Technological Research Projects in the Xinjiang Production and Construction Corps,China(No.2023AB017-02)+1 种基金the West Light Foundation for Young Scholar of Chinese Academy of Sciences(No.2021-XBQNXZ-018)the National Key Research and Development Program of China(No.2022YFF1302504)。
文摘Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain uncertain in arid mountain ecosystems,where climosequences are quite different from other ecosystems.To address this gap,this study investigated the distribution determinants of microbial communities,C cycling-related genes,and SOC fractions along an elevational gradient(1707–3548 m),with a mean annual precipitation(MAP)range of 38 to 344 mm,on the north slope of the central part of the Kunlun Mountains,China using a metagenomic approach.The results showed that elevation significantly influenced the α-diversity(Shannon index)and composition of microbial communities as well as the C cycling-related genes.The α-diversities of microbial taxa and C cycling-related genes linearly increased with the increase in MAP along the elevational gradient.The elevational patterns of the genes encoding glycoside hydrolases and glycosyl transferases(GTs)were mainly driven by soil electrical conductivity(EC),mean annual temperature(MAT),MAP,and plant diversity.Furthermore,mineral-associated organic C(MAOC),particulate organic C(POC),and their sum generally increased with elevation.However,the MAOC/POC ratio followed a unimodal pattern,suggesting greater stability of the SOC pool in the mid-elevation regions.This unimodal pattern was likely influenced by the abundances of Actinobacteria and the genes encoding GTs and carbohydrate esterases and the threshold effects of soil EC and MAT.In summary,our findings indicate that the distribution patterns of microbial communities and C cycling-related genes along the elevational gradient in an arid ecosystem are distinct from those in the regions with higher MAP,facilitating the prediction of climate change effects on SOC metabolism under more arid conditions.Soil salinity,plant diversity,precipitation,and temperature are the main regulatory factors of microbial C metabolism processes,and they potentially play a central role in mediating SOC pool stability.
基金supported by Uttarakhand Council for Biotechnology(grant number UCB/R&D PROJECT/2022/20 dated 06.05.2022).
文摘Allium stracheyi(Baker)is widely utilized as a culinary herb and is typically encountered in the higher elevations of the Himalayas.Consequently,it is of great significance to compare the ecological adaptability of this indigenous species to alternative habitats and its introduction into new environments.This research aims to investigate and gain a comprehensive understanding of A.stracheyi,also known as faran,in Uttarakhand region.We aim to examine how this plant adapts morphologically,physiologically,biochemically,and anatomically to varying elevations,specifically at 550,2200,2460,and 3400 m above mean sea level(m AMSL).This plant demonstrated remarkable morphophysiological adjustments across various aspects of its development,encompassing modified growth patterns,alterations in leaf dimensions,leaf count,etc..Moreover,biochemical adaptations have been identified as pivotal in bolstering the plant resilience to the stress associated with higher elevation.Enzymes like superoxide dismutase(SOD)and peroxidase(POD)exhibited significant responsiveness to elevational variations,contributing to the plant's ability to confront the challenges posed by high-elevational conditions.In terms of anatomy,the plant manifested alterations in its leaf and vascular tissues along the elevational gradient.These modifications involve an increased density of stomata and a greater count of vascular bundles,optimizing gas exchange and adaptation to water stress in frequently encountered harsh environmental conditions at higher elevations.Understanding the adaptive mechanisms employed by A.stracheyi provides valuable insights,especially in forecasting how A.stracheyi might respond to global climate change,particularly in regions affected by habitat fragmentation.
文摘Much of the world's biodiversity lies in heterogeneous mountain areas with their diverse environments.As an example,Iranian montane ranges are highly diverse,particularly in the Irano-Turanian phytogeographical region.Understanding plant diversity patterns with increasing elevation is of high significance,not least for conservation planning.We studied the pattern of species richness,Shannon diversity,endemic richness,endemics ratio,and richness of life forms along a 3900 m elevational transect in Mount Palvar,overlooking the Lut Desert in Southeast Iran.We also analyzed the effect of environmental variables on species turnover along the vertical gradient.A total of 120 vegetation plots(10 m×10 m)were sampled along the elevational transect containing species and environmental data.To discover plant diversity pattern along the elevational gradient,generalized additive model(GAM)was used.Non-metric multidimensional scaling(NMDS)was applied for illustrating the correlation between species composition and environmental variables.We found hump-shaped pattern for species richness,Shannon diversity,endemic richness,and species richness of different life forms,but a monotonic increasing pattern for ratio of endemic species from low to high elevations.Our study confirms the humped pattern of species richness peaking at intermediate elevations along a complete elevational gradient in a semi-arid mountain.The monotonic increase of endemics ratio with elevation in our area as a case study is consistent with global increase of endemism with elevation.According to our results,temperature and precipitation are two important climatic variables that drive elevational plant diversity,particularly in seasonally dry areas.Our study suggests that effective conservation and management are needed for this low latitude mountain area along with calling for long-term monitoring for species redistribution.
基金supported by the National Natural Science Foundation of China(Nos.31900204,32071671,32030071)the Postdoctoral Research Foundation of China(grant no.2019M652674)the Fundamental Research Funds for the Central Universities(grant no.CCNU22LJ003).
文摘Reproductive strategies of sexually dimorphic plants vary in response to the environment.Here,we ask whether the sexual systems of Fagopyrum species(i.e.,selfing homostylous and out-crossing distylous)represent distinct adaptive strategies to increase reproductive success in changing alpine environments.To answer this question,we determined how spatial and temporal factors(e.g.,elevation and peak flowering time)affect reproductive success(i.e.,stigmatic pollen load)in nine wild Fagopyrum species(seven distylous and two homostylous)among 28 populations along an elevation gradient of 1299-3315 m in the Hengduan Mountains,southwestern China.We also observed pollinators and conducted hundreds of hand pollinations to investigate inter/intra-morph compatibility,self-compatibility and pollen limitation in four Fagopyrum species(two distylous and two homostylous).We found that Fagopyrum species at higher elevation generally had bigger flowers and more stigmatic pollen loads;lateflowering individuals had smaller flowers and lower pollen deposition.Stigmatic pollen deposition was more variable in distylous species than in homostylous species.Although seed set was not pollenlimited in all species,we found that fruit set was much lower in distylous species,which rely on frequent pollinator visits,than in homostylous species capable of autonomous self-pollination.Our findings that pollination success increases at high elevations and decreases during the flowering season suggest that distylous and homostylous species have spatially and temporally distinct reproductive strategies related to environment-dependent pollinator activity.
基金carried out in the framework of the 1331 Project of Cultural Ecology Collaborative Innovation Center in Wutai Mountain (00000342)co-financed by Program for the Philosophy and Social Sciences Research of Higher Learning Institutions of Shanxi (2022J027)+1 种基金Applied Basic Research Project of Shanxi Province (202203021221225)Basic Research Project of Xinzhou Science and Technology Bureau (20230501)。
文摘Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.
基金supported by the Public Welfare Project of the National Scientific Research Institution (No.CAFRIFEEP201101),Chinathe National Biological Specimens and Resources Sharing Platform in Nature Reserve (No.2005DKA21404)
文摘Acidobacteria is one of the most dominant and abundant phyla in soil,and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational diversity patterns. We selected four elevation gradients from 1000 to 2800 m with typical vegetation types of the northern slope of Shennongjia Mountain in central China. The vegetation types were evergreen broadleaved forest,deciduous broadleaved forest,coniferous forest and sub-alpine shrubs. We analyzed the soil acidobacterial community composition,elevational patterns and the relationship between Acidobacteria subdivisions and soil enzyme activities by using the 16 S rRNA meta-sequencing technique and multivariate statistical analysis. The result found that 19 known subdivisions as well as an unclassified phylotype were presented in these forest sites,and Subdivision 6 has the highest number of detectable operational taxonomic units（OTUs）. A significant single peak distribution pattern（P 〈 0.05） between the OTU number and the elevation was observed. The Jaccard and Bray–Curtis index analysis showed that the soil Acidobacteria compositional similarity significantly decreased（P 〈 0.01） with the increase in elevation distance. Mantel test analysis showed the most of the soil Acidobacteria subdivisions had the significant relationship（P 〈 0.01） with different soil enzymes. Therefore,soil Acidobacteria may be involved in different ecosystem functions in global elemental cycles. Partial Mantel tests and CCA analysis showed that soil pH,soil temperature and plant diversity may be the key factors in shaping the soil Acidobacterial community structure.
基金supported by the National Natural Science Foundation of China(3157044531570601+2 种基金31500509 and31570605)Postdoctoral Science Foundation of China(2013M540714 and 2014T70880)Collaborative Innovation Center of Ecological Security in the Upper Reaches of Yangze River
文摘Temperature and freeze-thaw events are two key factors controlling litter decomposition in cold biomes.Predicted global warming and changes in freeze-thaw cycles therefore may directly or indirectly impact litter decomposition in those ecosystems. Here, we conducted a2-year-long litter decomposition experiment along an elevational gradient from 3000 to 3600 m to determine the potential effects of litter quality, climate warming and freeze-thaw on the mass losses of three litter types [dragon spruce（Picea asperata Mast.）, red birch（Betula albosinensis Burk.）, and minjiang fir（Abies faxoniana Rehd. et Wild）]. Marked differences in mass loss were observed among the litter types and sampling dates. Decay constant（k） values of red birch were significantly higher than those of the needle litters. However, mass losses between elevations did not differ significantly for any litter type.During the winter, lost mass contributed 18.3-28.8 % of the net loss rates of the first year. Statistical analysis showed that the relationships between mass loss and litter chemistry or their ratios varied with decomposition periods. Our results indicated that short-term field incubations could overestimate the k value of litter decomposition.Considerable mass was lost from subalpine forest litters during the wintertime. Potential future warming may not affect the litter decomposition in the subalpine forest ecosystems of eastern Tibetan Plateau.
基金funded by the Korea Green Promotion Agency, Korea Forest Service
文摘Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.
基金supported by the National Natural Science Foundation of China(31770568,32071544)Natural Science Foundation of Shanghai(20ZR1418100)“Light of West China”Program of the Chinese Academy of Sciences。
文摘Mountain systems harbor an evolutionarily unique and exceptionally rich biodiversity,especially for amphibians.However,the associated elevational gradients and underlying mechanisms of amphibian diversity in most mountain systems remain poorly understood.Here,we explored amphibian phylogenetic and functional diversity along a 2600 m elevational gradient on Mount Emei on the eastern margin of the Qinghai-Tibetan Plateau in southwestern China.We also assessed the relative importance of spatial(area)and environmental factors(temperature,precipitation,solar radiation,normalized difference vegetation index,and potential evapotranspiration)in shaping amphibian distribution and community structure.Results showed that the phylogenetic and functional diversities were unimodal with elevation,while the standardized effect size of phylogenetic and functional diversity increased linearly with elevation.Phylogenetic net relatedness,nearest taxon index,and functional net relatedness index all showed a positive to negative trend with elevation,indicating a shift from clustering to overdispersion and suggesting a potential change in key processes from environmental filtering to competitive exclusion.Overall,our results illustrate the importance of deterministic processes in structuring amphibian communities in subtropical mountains,with the dominant role potentially switching with elevation.This study provides insights into the underlying assembly mechanisms of mountain amphibians,integrating multidimensional diversity.
基金supported by the CAS/SAFEA International Partnership Program for Creative Research Teams (KZZD-EW-TZ-06)
文摘Understanding the vertical distribution patterns of soil microbial community and its driving factors in alpine grasslands in the humid regions of the Tibet Plateau might be of great significance for predicting the soil microbial community of this type of vegetation in response to environmental change. Using phospholipid fatty acids （PLFA）, we investigated soil microbial community composition along an elevational gradient （3094-4131 m above sea level） on Mount Yajiageng, and we explored the impact of plant functional groups and soil chemistry on the soil microbial community. Except for Arbuscular Mycorrhizal fungi （AM fungi） biomarker 18：2ω6,9 increasing significantly, other biomarkers did not show a consistent trend with the elevational gradient. Microbial biomass quantified by total PLFAs did not show the elevational trend and had mean values ranging from 1.64 to 4.09 ktmol per g organic carbon （OC）, which had the maximum value at the highest site. Bacterial PLFAs exhibited a similar trend with total PLFAs, and its mean values ranged from 0.82 to 1.81 μmol （g OC）-1. The bacterial to fungal biomass ratios had the minimum value at the highest site, which might be related to temperature and soil total nitrogen （TN）. The ratios of Gram-negative to Gram-positive bacteria had a significantly negative correlation with soil TN and had the maximum value at the highest site. Leguminous plant coverage and soil TN explained 58% of the total variation in the soil microbial community and could achieve the same interpretation as the whole model. Other factors may influence the soil microbial community through interaction with leguminous plant coverage and soil TN. Soil chemistry and plant functional group composition in substantial amounts explained different parts of the variation within the soil microbial community, and the interaction between them had no impact on the soil microbial community maybe beeause long-term grazing greatly reduces litter. In sum, although there were obvious differences in soil microbial communities along the elevation gradient, there were no clear elevational trends found in general. Plant functional groups and soil chemistry respectively affect the different aspects of soil microbial community. Leguminous plant coverage and soil TN had important effects in shaping soil microbial community.
基金funded by the National Natural Science Foundation of China (41271126)the National Basic Research Program of China (2009CB825105)
文摘Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-climate interactions is vital for mountainous ecosystems. Water-use efficiency （WUE） provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands. This paper explored net primary productivity （NPP） and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin （TMJB）, Xinjiang of China, using the Biome-BGC model. The results showed that： 1 ） the NPP increased by 0.05 g C/（m2-a） with every increase of 1-m elevation, reached the maximum at the mid-high elevation （1,600 m asl）, and then decreased by 0.06 g C/（m2.a） per 1-m increase in elevation; 2） the grassland NPP was positively correlated with temperature in alpine meadow （AM, 2,700-3,500 m asl）, mid-mountain forest meadow （MMFM, 1,650-2,700 m asl） and low-mountain dry grassland （LMDG, 650-1,650 m asl）, while positive correlations were found between NPP and annual precipitation in plain desert grassland （PDG, lower than 650 m asl）; 3） an increase （from 0.08 to 1.09 g C/（m2.a）） in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009; and 4） remarkable differences in WUE were found among different elevations, in general, WUE increased with decreasing elevation, because water availability is lower at lower elevations; however, at elevations lower than 540 m asl, we did observe a decreasing trend of WUE with decreasing elevation, which may be due to the sharp changes in canopy cover over this gradient. Our research suggests that the NPP simulated by Biome-BGC is consistent with field data, and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity.
文摘Gene flow and demographic history can play important roles in the adaptive genetic differentiation of species, which is rarely understood in the high-altitude adaptive evolution of birds. To elucidate genetic divergence of populations in the great tit complex （Parus major, P. minor and P. cinereus） at different elevations, we compared the genetic structure and gene flow in hemoglobin genes with neutral loci. Our results revealed the elevationally divergent structure of αA-globin gene, distinctive from that of the/βA-globin gene and neutral loci. We further investigated gene flow patterns among the populations in the central-northern （〉 1,000 m a.s.l.）, south-eastern （〈 1,000 m a.s.l.） regions and the Southwest Mountains （〉2,000 m a.s.l.） in China. The high-altitude （〉 1,000 m a.s.l.） diverged aA-globin genetic structure coincidαed with higher αA-globin gene flow between highland populations, in contrast to restricted neutral gene flow concordant with the phylogeny. The higher aA-globin gene flow suggests the possibility of adaptive evolution during population divergence, contrary to the lower aA-globin gene flow homogenized by neutral loci during population expantion. In concordance with patterns of historical gene flow, genotypic and allelic profiles provide distinctive patterns of fixation in different high-altitude populations. The fixation of alleles at contrasting elevations may primarily due to highland standing variants aA49Asn/72Asn/108Ala originating from the south-western population. Our findings demonstrate a pattern of genetic divergence with gene flow in major hemoglobin genes depending on population demographic history.
基金supported by the National Natural Science Foundation of China Granted to Yongjie Wu(No.31501851,31772478)the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists to Per Alstrom(No.2011T2S04)
文摘Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because patterns of elevational diversity can vary among lineages and mountain systems it remains difficult to extrapolate findings from one montane region to another,or among lineages.In this study,we assessed patterns and drivers of avian diversity along an elevational gradient on the eastern slope of Mt.Gongga,the highest peak in the Hengduan Mountain Range in central China,and a mountain where comprehensive studies of avian diversity are still lacking.Methods:We surveyed bird species in eight 400-m elevational bands from 1200 to 4400 m a.s.l.between 2012 and 2017.To test the relationship between bird species richness and environmental factors,we examined the relative importance of seven ecological variables on breeding season distribution patterns:land area(LA),mean daily temperature(MDT),seasonal temperature range(STR),the mid-domain effect(MDE),seasonal precipitation(SP),invertebrate biomass(IB) and enhanced vegetation index(EVI).Climate data were obtained from five local meteorological stations and three temperature/relative humidity smart sensors in 2016.Results:A total of 219 bird species were recorded in the field,of which 204 were recorded during the breeding season(April–August).Species richness curves(calculated separately for total species,large-ranged species,and smallranged species) were all hump-shaped.Large-ranged species contributed more to the total species richness pattern than small-ranged species.EVI and IB were positively correlated with total species richness and small-ranged species richness.LA and MDT were positively correlated with small-ranged species richness,while STR and SP were negatively correlated with small-ranged species richness.MDE was positively correlated with large-ranged species richness.When we considered the combination of candidate factors using multiple regression models and model-averaging,total species richness and large-ranged species richness were correlated with STR(negative) and MDE(positive),while small-ranged species richness was correlated with STR(negative) and IB(positive).Conclusions:Although no single key factor or suite of factors could explain patterns of diversity,we found that MDE,IB and STR play important but varying roles in shaping the elevational richness patterns of different bird species categories.Model-averaging indicates that small-ranged species appear to be mostly influenced by IB,as opposed to large-ranged species,which exhibit patterns more consistent with the MDE model.Our data also indicate that the species richness varied between seasons,offering a promising direction for future work.
基金supported by the National Key Basic Research Program of China (2014CB954100)Yunnan Provincial Foundation of Science and Technology (2014GA003)the QueenslandChinese Academy of Sciences Biotechnology Fund(GJHZ1130)
文摘Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration.Although soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients in different climatic zones is still unknown. This paper investigates seed density,species composition and nonconstituent species of forest soil seed banks in Yunnan Province, southwest China. Similarity between the soil seed bank and standing vegetation was also examined. We collected soil samples from sites spanning 12 elevations in tropical rain forests, subtropical evergreen broadleaved forests and subalpine coniferous forests, and transported them to a glasshouse for germination trials for species identification. The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests. Seeds of woody species dominated the soil seed banks of tropical and subtropical forests, while herbs dominated those of subalpine forests.The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests, followed by subtropical forests but were completely absent from subalpine forests.
基金We thank Jiahui Chen for his kind help to provide the data source of functional traits.We thank Lu Sun for his kind help with R.This study was supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20050203)and the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1802232).
文摘Elevational patterns of trait occurrence and functional diversity provide an important perspective for understanding biodiversity.However,previous studies have mostly examined functional diversity at the community scale.Here,we examined large-scale patterns of trait occurrence and functional diversity in Delphinium along an elevational gradient from 1000 to 5700 m in the Hengduan Mountains,SW China.Elevational distribution and trait data of 102 Delphinium species were compiled to evaluate the patterns of interspecific traits,species richness,and functional diversity.We found that the distribution of species richness showed a unimodal curve that peaked between 3500 and 4000 m;functional diversity and traits showed different patterns along an elevational gradient The functional diversity increased at a lower rate along an elevation gradient,whereas species richness continued to increase.Species with large ranges and non-endemic species were most affected by geometric constraints.Richness of species endemic to the Hengduan Mountains peaked at higher elevations,likely due to increased speciation and restricted dispersion under alpine conditions.We conclude that the middle elevation region is not only the functionally richest but also the most functionally stable region for Delphinium,which could be insurance against environmental change.Extreme conditions and strong environmental filters in an alpine environment may cause the convergence of species traits,which could relate to reducing nutrient trait investment and increasing reproductive trait investment.We conclude that large-scale studies are consistent with previous studies at the community scale.This may indicate that the relationship between functional diversity and species richness across different scales is the same.
基金supported by grants from the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0501)China’s Biodiversity Observation Network(Sino-BON)。
文摘Identifying how reproductive strategies such as the trade-off between clutch size versus egg mass vary with elevational gradients is essential for our understanding of life-history evolution.We studied lacertid lizards(Eremias argus)in China,from six populations at different altitudes,to assess elevational variation in reproductive strategy.We found significant between-population variation in maternal body size and clutch mass,but these variations were not explained by elevational differences.However,high-elevation females tended to produce smaller clutches of larger eggs compared with their low-elevation counterparts,demonstrating an elevational change in the trade-off between egg size and number.The egg size-number trade-off is a reproductive strategy that may favor large offspring,better enabling them to survive severe and unpredictable environments found at high elevations.
基金funded by the Russian Foundation for Basic Research (project no.17-04-00315)
文摘In mountain ecosystems,plants are sensitive to climate changes,and an entire range of species distribution can be observed in a small area.Therefore,mountains are of great interest for climate–growth relationship analysis.In this study,the Siberian spruce’s(Picea obovata Ledeb.)radial growth and its climatic response were investigated in the Western Sayan Mountains,near the SayanoShushenskoe Reservoir.Sampling was performed at three sites along an elevational gradient:at the lower border of the species range,in the middle,and at the treeline.Divergence of growth trends between individual trees was observed at each site,with microsite landscape-soil conditions as the most probable driver of this phenomenon.Cluster analysis of individual tree-ring width series based on inter-serial correlation was carried out,resulting in two sub-set chronologies being developed for each site.These chronologies appear to have substantial differences in their climatic responses,mainly during the cold season.This response was not constant due to regional climatic change and the local influence of the nearby Sayano-Shushenskoe Reservoir.The main response of spruce to growing season conditions has a typical elevational pattern expected in mountains:impact of temperature shifts with elevation from positive to negative,and impact of precipitation shifts in the opposite direction.Chronologies of trees,growing under more severe micro-conditions,are very sensitive to temperature during September–April and to precipitation during October–December,and they record both inter-annual and long-term climatic variation.Consequently,it would be interesting to test if they indicate the Siberian High anticyclone,which is the main driver of these climatic factors.
基金supported by the Key Project of National Key Research and Development Plans(Grant No.2016YFC0503106)
文摘It remains unclear whether the elevational diversity gradients observed in seed plants across different taxonomic levels （family, genus, and species） are driven by the same macro-environmental variables. In this study, seed plant elevational distribution data from the Lancang River Nature Reserve （Yunnan, China） were used to investigate spatial patterns in diversity and their environ- mental correlates, comparing across taxonomic levels. Environmental variables included energy availability, climate seasonality and environmental heterogeneity. All taxonomic levels （family, genus, and species） were found to have strong elevational richness gradients, with the strength of the gradient weakening at higher taxonomic levels. Spatial patterns in richness were explained by a combination of contemporary environmental variables and the mid-domain effect at all taxonomic levels. The independent effects of temperature- and precipitation-related variables were similar in explaining geographical patterns of family, genus and species richness. Energy, seasonality and heterogeneity variables influenced seed plant spatial richness at different taxonomic levels in similar ways.
