Litter Decomposition of Emergent Plants along an Elevation Gradient in Wetlands of Yunnan Plateau,China

The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknown. In this study, we conducted a one-year litter decomposition experiment along an elevation gradient from 1891 m to 3260 m on the Yurman Plateau of Southwest China, using different litter types to determine the influences of climate change, litter quality and microenvironment on the decomposition rate. The results showed that the average decomposition rate （K） increased from 0.608 to 1.152, and the temperature sensitivity of litter mass losses was approximately 4.98%/℃ along the declining elevation gradient. Based on a correlation analysis, N concentrations and C ： N ratios in the litter were the best predictors of the decomposition rate, with significantly positive and negative correlations, respectively. Additionally, the cumulative effects of decomposition were clearly observed in the mixtures of Scirpus tabernaemontani and Zizania caduciflora. Moreover, the litter decomposition rate in the water was higher than that in the sediment, especially in high-elevation areas where the microenvironment was significantly affected by temperature. These results suggest that future climate warming will have significant impacts on plateau wetlands, which have important fimctions in biogeochemical cycling in cold highland ecosystems.

Temporal changes in wetland plant communities with decades of cumulative water pollution in two plateau lakes in China's Yunnan Province

Abstract： Wetland plant communities in the plateau lakes of Yunnan Province, China, have decreased significantly over the past decades. To better understand this degradation, we analyzed the processes and characteristics of changes in wetland plant communities in two of the largest lakes in Yunnan Province, Dianchi and Erhai lakes. We collected records of native and alien plant communities in the two lakes from literature published from the 195os to current period. We calculated plant community types and their area in some historical periods when related data were reported, and analyzed the relationship between chances in nlant communities and water nollution. InDianehi Lake, 12 community types of native plant communities, covering over 80% of the surface in the 195os and 196os, were reduced to four types covering 2.4% by the late 2ooos. Alien plant communities started to appear in the lake in the late 197os, and have since come to cover 4.9% of the lake surface, thereby becoming dominant. In Erhai Lake, 16 community types of native plant communities, covering 47.1% of the lake surface in the late 197os, declined to lo community types, covering 9.3% of the surface, by the late 2ooos. Alien plant communities appeared in the middle 198os, and at present cover 0.7% of the surface area. It was indicated that changes in plant communities were significant related to water eutrophication. The area occupied by native and alien plant communities was, respectively, negatively andpositively related to the content of nutrients in water. This showed lacustrine pollution played an important role in native plant loss and alien plant invasion in the two plateau lakes.

Erratum to:Temporal changes in wetland plant communities with decades of cumulative water pollution in two plateau lakes in China’s Yunnan Province

The Electronic Supplementary Material of the article entitled“Temporal changes in wetland plant communities with decades of cumulative water pollution in two plateau lakes in China's Yunnan Province”at https://doi.org/10.1007/s11629-016-4037-9 are swapped with the Electronic Supplementary Material of the article entitled“Tracing environmental lead sources on the Ao mountain of China using lead isotopic composition and biomonitoring"at https://doi.org/10.1007/s11629-016-4327-2.

Honoring a legend: Celebrating the life and legacy of Professor Heng Li

Professor Heng Li(李恒,March 9,1929-January 12,2023)was a legendary plant taxonomist and phytogeographer at the Kunming Institute of Botany,Chinese Academy of Sciences(Fig.1).She made important contributions to our understanding of China's flora,including the biodiversity and biogeography of Dulong Valley and the Gaoligong Mountains,as well as the vegetation of plateau lakes and wetlands in Southwest China.Professor Heng Li received her Bachelor's degree in Russian from Beijing Foreign Studies University in 1956 and immediately joined the Institute of Geography(now Institute of Geographic Sciences and Natural Resources Research),Chinese Academy of Sciences,as a Russian translator.In 1961,Prof.

农田开垦对三江平原湿地土壤种子库影响及湿地恢复潜力

种子库是湿地植被恢复的重要途径之一,不同时期的耕作土壤中残留的种子对开垦湿地恢复具有重要的作用。本文采用温室萌发法在两种水分条件下对三江平原天然湿地、不同开垦年限湿地种子库结构和规模进行了研究,以了解不同开垦年限湿地种子库特征及其在湿地植被恢复中的潜力。本次实验共萌发物种50种,随着开垦年限增加,萌发物种逐渐减少,天然湿地、开垦1年、3年、10年、20年的湿地分别为34种、31种、21种、21种和8种,萌发物种数与种子库规模均表现出极显著差异(F1=8.32,F2=5.946,P<0.001)。种子库密度以天然湿地和开垦1年湿地最大,分别为7624粒/m2,9836粒/m2。随着开垦年限增加,种子库规模逐渐减小,开垦3年、10年种子库密度为4336粒/m2,4872粒/m2。开垦20 a后,显著减少为432粒/m2。湿润条件下萌发物种数及种子密度显著高于淹水处理,种子库具有明显的分层现象,0—5 cm土层种子库规模显著高于5—10 cm。小叶章(Calamagrostis angustifolia)作为该地区优势物种,由最初的1192粒/m2,经过20 a开垦后在种子库中消失。研究表明,在一定的开垦年限范围内,开垦湿地土壤中仍然保留大量的湿地物种种子,在湿地恢复中具有重要的作用。

Transfer and Transformation of Soil Iron and Implications for Hydrogeomorpholocial Changes in Naoli River Catchment, Sanjiang Plain, Northeast China

Wetland soils are characterized by alternating redox process due to the fluctuation of waterlogged conditions. Iron is an important redox substance, and its transfer and transformation in the wetland ecosystem could be an effective indicator for the environment changes. In this paper, we selected the Naoli River catchment in the Sanjiang Plain, Northeast China as the study area to analyze the dynamics of transfer and transformation of soil iron, and the relationship between iron content change and environmental factors. The results show that the total and crystalline iron contents reach the peak in the depth of 60 cm in soil profile, while the amorphous iron content is higher in the topsoil. In the upper reaches, from the low to high landscape positions, the total and crystalline iron contents decrease from 62.98 g/kg to 41.61 g/kg, 22.82 g/kg to 10.53 g/kg respectively, while the amorphous iron content increases from 2.42 g/kg to 8.88 g/kg. Amorphous iron content has positive correlation with organic matter and soil water contents, while negative correlation with pH. Moreover, both the crystalline and amorphous iron contents present no correlation with total iron content, indicating that environmental factors play a more important role in the transfer and transformation of iron other than the content of the total iron. Different redoximorphic features were found along the soil profile due to the transfer and transformation of iron. E and B horizons of wetland soil in the study area have a matrix Chroma 2 or less, and all the soil types can meet the criteria of American hydric soil indicators except albic soil.

Photosynthetic response of Scirpus validus and Typha orientalis to elevated temperatures in Dianchi Lake, Southwestern China

Understanding the effects of simulated warming on photosynthetic performance of aquatic plants may provide strong supports for predicting future dynamics of wetland ecosystems in the context of climate change. The plateau wetlands located in Yunnan province are highly sensitive to climate warming due to their high altitude and cold temperature. Here, we conducted a temperaturecontrolled experiment using two temperature manipulations(ambient temperature as the control and 2℃ higher than ambient temperature as the warmed treatment) to determine the photosynthetic characteristics of two lakeside dominant species(Scirpus validus Vahl and Typha orientalis C. Presl.) in Dianchi Lake. Net photosynthetic rate(P_n), stomatal conductance(G_s), intercellular CO_2 concentration(Ci), and transpiration rate of S. validus that grew under warmed treatment were all significantly higher than those under the control. Gs and Ci of T. orientalis showed similar patterns as S. validus did. For the response curves of Pn to photosynthetic active radiation(P_n-PAR) and intercellular CO_2 concentration(P_n-Ci), S. validus had higher P_n values under elevated temperatures than the control, while Pn-PAR and P_n-Ci curves of T. orientalis did not separate clearly under two temperature scenarios. Both S. validus and T. orientalis had higher maximum net photosynthetic rate, light saturation point, dark respiration rate, the maximum rate of RuBP carboxylation(V_(cmax)), maximum electron transport rate driving RuBP regeneration(J_(max)), the ratio of V_(cmax) to J_(max), triosephosphate utilization, and 1, 5-bishosphate carboxylase ribulose content under warmed treatment than those under the control. This study provides a preliminary step for predicting the future primary production and vegetation dynamics of plateau wetlands in Yunnan province.

祁连山中部不同海拔青海云杉径向生长对升温的响应分异

Understanding the radial growth trends of trees and their response to recent warming along elevation gradients is crucial for assessing how forests will be impacted by future climate change.Here,we collected 242 tree-ring cores from five plots across the Qinghai spruce(Picea crassifolia Kom.)forest belt(2600–3350 m a.s.l.)in the central Qilian Mountains,Northwest China,to study trends in the radial growth of trees and their response to climate factors with variable elevation.All the sampled P.crassifolia chronologies showed an increasing trend in the radial growth of trees at higher altitudes(3000–3350 m),whereas the radial growth of trees at lower altitudes(2600–2800 m)has decreased in recent decades.The radial growth of trees was limited by precipitation at lower elevations(L,ML),but mainly by temperature at higher elevation sites(MH,H,TL).Climate warming has caused an unprecedented increase in the radial growth of P.crassifolia at higher elevations.Our results suggest that ongoing climate warming is beneficial to forest ecosystems at high elevations but restricts the growth of forest ecosystems at low elevations.

Genetic Diversity of Chinese Medaka(Oryzias sinensis)in Dian Lake Drainage Area by ISSR Analysis

Chinese medaka(Oryzias sinensis),widely distributed in the plateau lakes,Yunnan Province,which was the indicative specie for the habitat quality of riparian zone in the wetland ecosystems and also was the key specie in the lake ecosystems,and also was one of the fishes who suffered the severe invasion of alien species.There,we investigated that the genetic diversity and population structure of the wild Chinese medaka by using inter-simple sequence repeat(ISSR)analysis.The samples(20 individuals in total)of Chinese medaka in three populations in the drainage area of Dian Lake were obtained.The 7 ISSR primers were picked out to assess the genetic diversity.The ISSR primers combinations revealed 82.69%polymorphism,among 52 genetic loci amplified.The sum of effective number of alleles and observed number of alleles were 1.492 4 and 1.826 9,respectively.The Shannon genetic diversity and Nei genetic diversity indexes of all the populations were 0.434 5 and 0.289 7,respectively.The gene differentiation(GST)was 0.198 9,and the gene flow(NM)was 2.013 2.The AMOVA demonstrated that only 6.65%of genetic variance came from inter-population,and 93.35%of genetic variance came from intra-population.Phylogenetic tree showed that 20 individuals from 3 populations were clustering mixed each other.Also,the principal coordinate analysis(PCA)supported the cluster analysis results.These results indicated that the genetic diversity of Oryzias sinensis was at the middle level,and there was no obvious genetic differentiation among the three populations of Oryzias sinensis.

Stand history is more important than climate in controlling red maple (Acer rubrum L.) growth at its northern distribution limit in western Quebec, Canada

Aims We examined growth of red maple(Acer rubrum l.)to evaluate environmental controls of its northern distributional limit in Eastern North america and its potential response to future climate change.Methods We collected growth data from nine sites located along a 300-km transect(47-49°N),which included frontier population of red maple and covered three bioclimatic domains in western Quebec.We ana-lyzed three growth variables:growth rates during the first 30 years of maple lifespan,cumulative basal area increment(ba I)over the most recent decade(2000-2009)and annual growth rate over the whole tree lifespan ranging from 58 to 112 years.We also examined growth sensitivity to climate by using response function analysis.Important Findingsthree different proxies of maple absolute growth(initial growth rate,ba I during 2000-09 and mean diameter growth rate)indicated a better growth with an increase in latitude.We speculate that stand history effectively overrode the direct effects of colder climate on maple growth along the s-N gradient.regeneration of maple in the southern sites likely occurred in canopy gaps,whereas in the north it was contingent upon large disturbances such as stand-replacing fires,which apparently provided more favorable light environment for maple growth than canopy gaps.the annual growth variability,which reflects effects of annual weather on growth and is largely independent from the absolute growth rate,was significantly affected by monthly climate,suggesting a positive effect of higher summer temperature in the northern part of the transect(48-49°N)and a negative effect of summer drought in the south(47-48°N).In the future,the natural and human disturbance regimes will be dominant controls of the actual biomass productivity of red maple at the northern limit of its present distribution range.Direct effects of climate on maple growth would likely be less important in this context,and will likely entail negative effect of increased summer drought in the southern part of the study area and positive effects of increased temperatures in the north.

Excessive plant compensatory growth:a potential endogenous driver of meadow degradation on the Qinghai-Tibetan Plateau

Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock overgrazing,climate change and overpopulation of small mammals are treated as important factors that cause the degradation of meadow ecosystems in the QTP.However,there are few hypotheses focus on the potential role of plant compensatory growth on meadow degradation.We proposed a compensatory growth-related hypothesis to understand the potential degradation process of meadow ecosystems in the QTP.We discussed that there are two stages of meadow degradation,i.e.the beginning stage of meadow degradation that is triggered by high-strength overcompensation;and the intensification stage of meadow degradation,which are driven by external factors such as climate warming,small mammals and thawing of permafrost.The mechanism of meadow degradation driven by plant compensatory growth is the asynchronism of plant consumption and the availability of soil nutrients.Our hypothesis that plant compensatory growth drives meadow degradation under the overgrazing condition requires re-examination and modification by testing the balance between soil nutrient cycling rates and the strength of plant compensatory growth in alpine regions.

Profiling the antibiotic resistome in soils between pristine and human-affected sites on the Tibetan Plateau

With increasing pressure from anthropogenic activity in pristine environments,the comprehensive profiling of antibiotic resistance genes(ARGs)is essential to evaluate the potential risks from human-induced antibiotic resistance in these under-studied places.Here,we characterized the microbial resistome in relatively pristine soil samples collected from four distinct habitats on the Tibetan Plateau,using a Smart chip based high-throughput q PCR approach.We compared these to soils from the same habitats that had been subjected to various anthropogenic activities,including residential sewage discharge,animal farming,atmospheric deposition,and tourism activity.Compared to pristine samples,an average of23.7%more ARGs were detected in the human-affected soils,and the ARGs enriched in these soils mainly encoded resistances to aminoglycoside and beta-lactam.Of the four habitats studied,soils subjected to animal farming showed the highest risks of ARG enrichment and dissemination.As shown,the number of ARGs enriched(a total of 42),their fold changes(17.6 fold on average),and the co-occurrence complexity between ARGs and mobile genetic elements were all the highest in fecal-polluted soils.As well as antibiotics themselves,heavy metals also influenced ARG distributional patterns in Tibetan environments.However,compared to urban areas,the Tibetan Plateau had a low potential for ARG selection and exhibited low carriage of ARGs by mobile genetic elements,even in environments impacted by humans,suggesting that these ARGs have a limited capacity to disseminate.The present study examined the effects of multiple anthropogenic activities on the soil resistomes in relatively pristine environments.

Aboveground biomass and its spatial distribution pattern of herbaceous marsh vegetation in China

Herbaceous marsh is the most widely distributed type of marsh wetland ecosystem,and has important ecological functions such as water conservation,climate regulation,carbon storage and fixation,and sheltering rare species.The carbon sequestration function of herbaceous marsh plays a key role in slowing climate warming and maintaining regional environmental stability.Vegetation biomass is an important index reflecting the carbon sequestration capacity of wetlands.Investigating the biomass of marsh vegetation can provide a scientific basis for estimating the carbon storage and carbon sequestration capacity of marshes.Based on field survey data of aboveground biomass of herbaceous marsh vegetation and the distribution data set of marsh in China,we analyzed the aboveground biomass and its spatial distribution pattern of herbaceous marsh on a national scale for the first time.The results showed that in China the total area of herbaceous marsh was 9.7×10^(4) km^(2),the average density of aboveground biomass of herbaceous marsh vegetation was 227.5±23.0 g C m-2(95%confidence interval,the same below),and the total aboveground biomass was 22.2±2.2 Tg C(1 Tg=1012 g).The aboveground biomass density of herbaceous marsh vegetation is generally low in Northeast China and the Tibetan Plateau,and high in central North China and coastal regions in China.In different marsh distribution regions of China,the average biomass density of herbaceous marsh vegetation from small to large was as follows:temperate humid and semi-humid marsh region(182.3±49.3 g C m^(-2))<Tibetan Plateau marsh region(243.9±26.6 g C m-2)<temperate arid and semi-arid marsh region(300.5±73.2 g C m-2)<subtropical humid marsh region(348.4±59.0 g C m-2)<coastal marsh region(675.4±73.8 g C m-2). Due to the different area of herbaceous marsh, the total aboveground biomass of herbaceous marsh vegetation in different marsh distribution regions was the largest in the temperate humid and semi-humid marsh region(9.6±2.6 Tg C), and was the smallest in the coastal marsh region(1.1±0.1 Tg C). The spatial distribution of aboveground biomass of herbaceous marsh vegetation in China has obvious non-zonality characteristics, but also presents certain zonality in some regions. The aboveground biomass of herbaceous marsh vegetation in the Tibetan Plateau decreased with the increase of altitude. With the aggravation of drought, the aboveground biomass of herbaceous marsh vegetation in temperate humid and semi-humid regions and temperate arid and semi-arid regions decreased first and then did not obviously change. The aboveground biomass of herbaceous marsh vegetation in temperate humid and semi-humid regions was relatively larger in the regions with higher average annual temperature. The results can provide scientific basis for accurately evaluating the adjustment action of wetland ecosystems on climate, and provide decision support for adaptive management of wetland ecosystems.

Functional diversity and redundancy of subalpine meadows subjected to anthropogenic disturbances

Aims The aims of this study were to assess how functional diversity(FD)and functional redundancy respond to subalpine meadow ecosystem degradation under anthropogenic disturbance and how species contribute to functional redundancy along the disturbance gradient.Methods The study was carried out in the subalpine meadow in Mount Jade Dragon,which is located at the southeastern edge of the Tibetan Plateau.Four disturbance intensities[no disturbance(ND),weak disturbance(WD),moderate disturbance(MD)and severe disturbance(SD)]were identified.Species richness,soil properties and five key plant functional traits were assessed along the disturbance gradient.Simpson’s diversity index,FD based on the Rao algorithm,functional redundancy,community-weighted mean of each functional trait and species-level functional redundancy were determined.Important Findings Unimodal change pattern of FD and functional redundancy along the disturbance gradient were found in the present study,with their maximum in MD and WD,respectively.Species diversity showed a decreasing trend with increasing disturbance intensity.As disturbance intensified,species with traits related to conservative growth strategies,such as low specific leaf area(SLA)and high leaf dry matter content(LDMC),decreased,whereas species with resource acquisitive strategies,such as small plant,high SLA and low LDMC,increased in the community.At the species level,species showed species-specific roles in functional redundancy.Notably,some species were important in the community in terms of their unique function.For instance,Ligularia dictyoneura in ND and Potentilla delavayi in MD and SD.