Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions ...Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.展开更多
Plant community composition typically undergoes progressive changes along environmental gradients.However,most experimental studies have focused on individual communities,so it remains unclear how exogenous nutrient i...Plant community composition typically undergoes progressive changes along environmental gradients.However,most experimental studies have focused on individual communities,so it remains unclear how exogenous nutrient inputs affect the stability of plant communities along environmental gradients.Along a rainfall gradient on the northern Tibetan Plateau,we conducted an 8-year nitrogen(N)addition experiment in four alpine grasslands:alpine desert steppe(ADS),alpine steppe(AS),alpine meadow steppe(AMS),alpine meadow(AM),and we used twoway ANOVA to examine the effects of N addition on the temporal stability of these different alpine grasslands.We found that community aboveground biomass showed saturation trends in AM and AMS with increasing N gradients,while there was no change in AS and a gradual increase in ADS.The temporal stability showed different patterns of gradual decreases in ADS and AM,and a unimodal trend in AMS with increasing N gradients.However,N addition had no effect on the temporal stability of AS.Dominant species stability was the controlling factor for alpine grasslands along the transect,while the effect of asynchrony gradually increased with decreasing precipitation.These findings highlight that community composition,especially the dominant species,along the environmental gradient can mediate the effects of N inputs on community temporal stability.Thus,the conservation and restoration of the dominant species are particularly important under future scenarios of increased atmospheric N deposition.展开更多
Land use influences soil biota community composition and diversity,and then belowground ecosystem processes and functions.To characterize the effect of land use on soil biota,soil nematode communities in crop land,for...Land use influences soil biota community composition and diversity,and then belowground ecosystem processes and functions.To characterize the effect of land use on soil biota,soil nematode communities in crop land,forest land and fallow land were investigated in six regions of northern China.Generic richness,diversity,abundance and biomass of soil nematodes was the lowest in crop land.The richness and diversity of soil nematodes were 28.8and 15.1%higher in fallow land than in crop land,respectively.No significant differences in soil nematode indices were found between forest land and fallow land,but their network keystone genera composition was different.Among the keystone genera,50%of forest land genera were omnivores-predators and 36%of fallow land genera were bacterivores.The proportion of fungivores in forest land was 20.8%lower than in fallow land.The network complexity and the stability were lower in crop land than forest land and fallow land.Soil pH,NH_(4)^(+)-N and NO_(3)^(–)-N were the major factors influencing the soil nematode community in crop land while soil organic carbon and moisture were the major factors in forest land.Soil nematode communities in crop land influenced by artificial management practices were more dependent on the soil environment than communities in forest land and fallow land.Land use induced soil environment variation and altered network relationships by influencing trophic group proportions among keystone nematode genera.展开更多
Light climate is of key importance for the growth, community composition of submerged macrophytes in lakes and, they, in turn, are affected by lake depth and the degree of eutrophication. To test the relationships bet...Light climate is of key importance for the growth, community composition of submerged macrophytes in lakes and, they, in turn, are affected by lake depth and the degree of eutrophication. To test the relationships between submerged macrophyte presence and the ratio of Secchi disk depth(SDD) to water depth, i.e. SDD/depth, nutrients and wind, we conducted an extensive sampling campaign in a macrophyte-dominated area of the eastern region( n = 36) in 2016 in Lake Taihu, China, and combined the data gathered with results from extensive physico-chemical monitoring data from the entire lake. We confirmed that SDD/Depth is the primary factor controlling the community composition of macrophytes and showed that plant abundance increased with increasing SDD/Depth ratio( p < 0.01), but that only SDD/Depth > 0.4 ensured growth of submerged macrophytes. Total phosphorus and total nitrogen also influenced the growth and community composition of macrophytes( p < 0.01), while Chl a was an indirectly affecting factor by reducing underwater light penetration. Wave height significantly influenced plant abundance( p < 0.01), whereas it had little effect on the biomass( p > 0.05). The key to restore the macrophyte beds in the lake is to reduce the nutrient loading. A decrease of the water level may contribute as well in the shallow bays but will not bring plants back in the main part of the lake. As the tolerance of shade and nutrients varied among the species studied, this should be taken into account in the restoration of lakes by addition of plants.展开更多
Seasonal shifts play an important role in soil microbial community composition. This study examined the hypothesis that soil microbial community structure would vary with seasonal shifts in the Wuyi Mountains in South...Seasonal shifts play an important role in soil microbial community composition. This study examined the hypothesis that soil microbial community structure would vary with seasonal shifts in the Wuyi Mountains in Southeast China, and that two representative tree species （Castanopisi carlesii and Cunninghamia lanceolata） may have different soil microbial community composition. Phospholipids fatty acid analysis （PLFA） of seasonal shifts and was used to assess the effect vegetation types on soil microbial community structure. A total of 22 different PLFAs were identified from all the soil samples. The bacterial PLFAs accounted for 62.37% of the total PLFAs, followed by fungi （28.94%）, and the minimum was actinomycetes （6.41%）. Overall, the level of PLFAs in C. carlesii soil was greater than those in C. lanceolata soil, and significant differences were observed in some seasons. The amounts of total, bacteria, actinomycic and fungal PLFAs significantly changed with the seasons and followed a sequence order （summer 〉 autumn 〉 spring 〉 winter）. The bacteria/fungi PLFAs and G （＋）/G （-） PLFAs of two vegetation types also changed with the seasons and the ratios in summer and autumn were higher than those in spring and winter. The correlation analysis of microbial PLFAs and soil physicochemical properties showed that the total, bacteria, fungal, actinomycic, G （＋） and G （-） PLFAs were significantly positive correlation with TOC, TN, TP, TK and moisture content. We concluded that the seasonal shifts and vegetation types affect soil microbial community composition by changing the soil physicochemical properties.展开更多
Phytoplankton pigment patterns and community composition were investigated in the northern South China Sea using high-performance liquid chromatography and the CHEMTAX software from February 11 to 23, 2009. We recogni...Phytoplankton pigment patterns and community composition were investigated in the northern South China Sea using high-performance liquid chromatography and the CHEMTAX software from February 11 to 23, 2009. We recognized four different vertical distribution patterns of pigments: chlorophyll a (Chl a)-like type, divinyl chlorophyll a (DV Chl a) type, even distribution type, and surface type. The average value of ratios of accessory photo-protective pigments (APP) to accessory photo-synthetic pigments was 0.89±0.63 in the upper 50 m and 0.16±0.06 below 50 m depth. With increasing depth, APP decreased and photo-synthetically active radiation was attenuated. There was an obvious succession in the phytoplankton community from inshore to the open sea. Diatoms were dominant in the inshore region, while pelagophytes, Prochlorococcus, cyanobacteria and prymnesiophytes were dominant in the open sea. The vertical distribution of phytoplankton also differed greatly from inshore to the open sea. In the coastal and shelf region, diatoms were important components in the whole water column. Cyanobacteria also had a high abundance at the Subsurface Chlorophyll a Maxima (SCM) in the shelf region. In the slope and open sea, Prochlorococcus and cyanobacteria were important groups above the SCM, while pelagophytes dominated below the SCM.展开更多
Soil nematode communities can provide valuable information about the structure and functions of soil food webs,and are sensitive to agricultural practices,including short-term straw incorporation.However,currently,suc...Soil nematode communities can provide valuable information about the structure and functions of soil food webs,and are sensitive to agricultural practices,including short-term straw incorporation.However,currently,such effects under longterm straw incorporation conditions at different fertility levels are largely unknown.Thus,we conducted a 13-year ongoing experiment to evaluate the effects of long-term straw incorporation on the structure and functions of the soil food web in low and high fertility soils through analyzing its effects on nematode communities,food web indices and metabolic footprints.Four treatments were included:straw removal(–S)under non-fertilized(–NPK)or fertilized(+NPK)conditions;and straw incorporation(+S)under–NPK or+NPK conditions.Soil samples from a 0–20 cm depth layer were collected when wheat and rice were harvested.Compared with straw removal,straw incorporation increased the abundances of total nematodes,bacterivores,plant-parasites and omnivores-predators,as well the relative abundances of omnivores-predators with increases of 73.06,89.29,95.31,238.98,and 114.61%in–NPK soils and 16.23,2.23,19.01,141.38,and 90.23%in+NPK soils,respectively.Regardless of sampling times and fertilization effects,straw incorporation increased the diversity and community stability of nematodes,as indicated by the Shannon-Weaver diversity index and maturity index.Enrichment and structure index did not show significant responses to straw incorporation,but a slight increase was observed in the structure index.The analysis of nematode metabolic footprints showed that straw incorporation increased the plant-parasite footprint and structure footprint by 97.27 and 305.39%in–NPK soils and by 11.29 and 149.56%in+NPK soils,but did not significantly influence enrichment,bacterivore and fungivore footprints.In conclusion,long-term straw incorporation,particularly under a low fertility level,favored the soil nematodes and regulated the soil food web mainly via a top-down effect.展开更多
Background:Soil fungi play crucial roles in ecosystem functions.However,how snow cover change associated with winter warming affects soil fungal communities remains unclear in the Tibetan forest.Methods:We conducted a...Background:Soil fungi play crucial roles in ecosystem functions.However,how snow cover change associated with winter warming affects soil fungal communities remains unclear in the Tibetan forest.Methods:We conducted a snow manipulation experiment to explore immediate and legacy effects of snow exclusion on soil fungal community diversity and composition in a spruce forest on the eastern Tibetan Plateau.Soil fungal communities were performed by the high throughput sequencing of gene-fragments.Results:Ascomycota and Basidiomycota were the two dominant fungal phyla and Archaeorhizomyces,Aspergillus and Amanita were the three most common genera across seasons and snow manipulations.Snow exclusion did not affect the diversity and structure of soil fungal community in both snow-covered and snow-free seasons.However,the relative abundance of some fungal communities was different among seasons.Soil fungal groups were correlated with environmental factors(i.e.,temperature and moisture)and soil biochemical variables(i.e.,ammonium and enzyme).Conclusions:These results suggest that the season-driven variations had stronger impacts on soil fungal community than short-term snow cover change.Such findings may have important implications for soil microbial processes in Tibetan forests experiencing significant decreases in snowfall.展开更多
The oxygen minimum zones(OMZs)are globally expanding,yet the variation pattern of microbial communities related to dissolved oxygen levels remain unclear.Spatial variability of bacterial diversity and community compos...The oxygen minimum zones(OMZs)are globally expanding,yet the variation pattern of microbial communities related to dissolved oxygen levels remain unclear.Spatial variability of bacterial diversity and community composition(repre sented by 16 S rRNA)of six stations was investigated within the water column in the seamount area of Tropical Western Pacific Ocean(TWPO)in May 2019.The seawater has dissolved oxygen(DO)concentration of 3.01-6.68 mg/L and the core of the oxygen minimum zones was located between the depths of 650 m and 1750 m.The bacterial alpha-diversity showed unimodal pattern with the decreasing DO with depths and peaked in the upper oxycline(UO)of OMZs.The bacterial community structure of the mixed layer(ML)and the bottom layer clustered and separated from each other,while those of UO and the OMZ core(OM)clustered and overlapped.Overall,bacterial community composition transitioned from being Alphaproteobacteria and Gammaproteobacteria-dominant in ML to being Gammaproteobacteria and Nitrososphaeria/Deltaproteobacteria-dominant in UO and OM,and then changed to being Clostridia and unidentified Actinobacteria-dominant in the bottom layer.Moreover,both bacterial alpha-diversity and the abundant classes fitted varying sectioned functions with DO.The DO solely explained 40.37%of the variation of bacterial community composition among layers(P<0.001).The predicted function profiling showed that the water column was predominant by chemoheterotrophy,cyanobacteria,and photoautotrophy in ML,by chemoheterotrophy and nitrate/sulfide cycling in UO and OM,and by chemoheterotrophy and ferme ntation in the bottom layer.Our findings revealed the DO-associated variation in bacterial diversity and community composition,and help to clarify the potential responses of microbes and their involved biogeochemical processes to the expansion and intensification of OMZs.展开更多
We characterized variations in bacterioplankton community composition(BCC) in mesocosms subject to three different treatments. Two groups contained fish(group one: Cyprinus carpio; group two: Hypophthalmichthys molitr...We characterized variations in bacterioplankton community composition(BCC) in mesocosms subject to three different treatments. Two groups contained fish(group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-d period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis(DGGE) and real-time quantitative PCR(q PCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly diff erent between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected in C. carpio mesocosms. The redundancy analysis(RDA) result demonstrated that the BCC was closely related to the bottom-up(total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces(biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa(heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem.展开更多
To understand the potential impact of the Three Gorges Reservoir on the aquatic ecosystem after the damming of the Yangtze River,we studied the community composition and temporal abundance distribution of algae in two...To understand the potential impact of the Three Gorges Reservoir on the aquatic ecosystem after the damming of the Yangtze River,we studied the community composition and temporal abundance distribution of algae in two types of water bodies:a segment of the Jialing River near its confluence with the Yangtze River as an example of the river-lake type,and Shuanglong Lake in Chongqing as an example of the lake type.In total,107 species belonging to 58 genera of 7 phyla were identified in the study area of the Jialing River,dominated by three groups with 49.5% diatoms,29.0% chlorophytes,and 11.4% cyanobacteria in the community composition.There were 122 species belonging to 66 genera of 8 phyla in Shuanglong Lake,dominated by the same three groups with 19.7% diatoms,48.4% chlorophytes,and 22.2% cyanobacteria.The densities of total algae and individual dominant groups were all much higher in the lake.More species of diatoms were found in the river-lake segment;whereas more chlorophyte species and cyanobacteriaum species were in the lake.There were 17 dominant species including 8 diatoms,4 chlorophytes,3 cyanobacteria and 2 cryptophytes in the river-lake segment,and 21 species in the lake,including 2 diatoms,9 chlorophytes,6 cyanobacteria,3 cryptophytes and a dinoflagellate.In eutrophic conditions,chlorophytes and cyanobacteria may proliferate in a lake-type area and diatoms may cause algal bloom in a relatively faster-flow lake-river type area.展开更多
Objectives:To investigate the diversity and community composition of endophytes in Sinopodophyllum hexandrum(Royle)Ying.Methods:S.hexandrum samples(n=15)were collected at five sites on the Tibetan Plateau.High quality...Objectives:To investigate the diversity and community composition of endophytes in Sinopodophyllum hexandrum(Royle)Ying.Methods:S.hexandrum samples(n=15)were collected at five sites on the Tibetan Plateau.High quality sequences from high-throughput sequencing were clustered into operational taxonomic units(OTUs)by Clustering and Classification Inference with U-Statistics,and the OTUs were further divided into different genera according to Ribosomal Database Project classification.Alpha and beta diversity analyses were conducted to explore community diversity and composition.Results:A total of 1221 OTUs were obtained,representing 133 genera(with 98 specific to genus).The QJ and XH sampling sites had the most(n=67)and fewest(n=36)genera,respectively.The dominant fungi at the DT,LD,QJ and XH sites were Ascomycota,while the dominant fungi at the BX site were Basidiomycota.Tetracladium,Exophiala and Pseudogymnoascus showed obvious host preference in all samples.The dominant fungi in the three provinces were Tetracladium,Penicillium,and Cantharellales,respectively.The Shannon-Weiner diversity indices of the 15 samples ranged from 0.48 to 3.10.Endophytic fungi were clustered into three branches based on geographical location.Conclusion:Our findings provide a research basis for the exploitation and utilization of national medicinal plants with abundant microbial resources.展开更多
OBJECTIVE: To investigate composition of gut microbial community in a rat model of functional dyspepsia(FD) and to explore the interventional effects of Simo Tang(四磨汤, SMT). METHODS: A rat model of FD was establish...OBJECTIVE: To investigate composition of gut microbial community in a rat model of functional dyspepsia(FD) and to explore the interventional effects of Simo Tang(四磨汤, SMT). METHODS: A rat model of FD was established through the tail-clamping stimulation method. The rat model of FD was assessed by the state of rats, their weight, sucrose preference rate, and intestinal propulsion rate. The DNA was extracted from stool samples after treatment with SMT. Amplified polymerase chain reaction(PCR) products of the 16S r DNA were sequenced using Novase Q6000 after construction of libraries. Composition of gut microbial community in the stool samples was determined and analyzed by cluster analysis, bioinformatic analysis, and analysis of α-diversity and β-diversity.RESULTS: The rat model of FD was successfully established using the tail-clamping stimulation method. The statistical results of cluster analysis of operational taxonomic units(OTUs) showed that the relative abundance of OTUs in the FD group was the lowest, while it was the highest in the normal(N) group. The composition of microbiome in the four groups was similar at phyla level. Compared with the FD group, the abundance of Firmicutes was downregulated, and the abundance of Proteobacteria and Bacteroidetes was upregulated in the Simo Tang(SMT) and high-dose Simo Tang(SMT.G) groups. The ratio of Bacteroidetes/Firmicutes was also elevated. According to the analysis of α-diversity and β-diversity, the abundance of flora in FD rats was significantly reduced. The treatment using SMT appeared beneficial to improve the diversity of flora. SMT could improve the intestinal flora in FD rats. The results showed that FD rats had intestinal flora imbalance, and species diversity increased. The results suggested that SMT could regulate the disorders of intestinal flora caused by FD. CONCLUDIONS: SMT could restore gut homeostasis and maintain gut flora diversity by modulating the gut microbiota and its associated metabolites in rats, thereby treating gastrointestinal diseases.展开更多
When the dominant species in a plant community are palatable,many believe that large herbivores will reduce the dominant species and promote the proportion of previously suppressed species.However,this view may not al...When the dominant species in a plant community are palatable,many believe that large herbivores will reduce the dominant species and promote the proportion of previously suppressed species.However,this view may not always hold true.We conducted a 4-year yak grazing experiment on the Qinghai-Tibet Plateau and tracked the plant compositions of the rotational grazing(RG)and grazing exclusion(GE)grasslands during the four years.The results showed that in the absence of yaks under GE,the plant community was dominated by two palatable species,Kobresia pygmaea and Stipa capillata,due to their small leaf area and rapid growth strategy.The presence of yaks under RG significantly inhibited S.capillata and over half of the forbs,while the proportion of K.pygmaea increased and it became the absolute dominant species,contradicting the view that large herbivores inhibit palatable species.Interannually,the dominance of K.pygmaea under RG decreased in the dry year,leading to an increase in the dominance of the other eight species.Under GE,the dominance of K.pygmaea declined notably in the dry year,while S.capillata and seven other forbs increased substantially.Overall,these results suggest that K.pygmaea is grazing-tolerant but not drought-tolerant,whereas the other eight species are drought-tolerant but not grazingtolerant.At the community level,community composition shifts resulting from succession after grazing exclusion exceeded those caused by drought,drought tends to induce community species turnover while grazing tends to induce species abundance variations.In summary,our conclusions remind ranch managers that when considering the impact of livestock on plant community composition,they should factor in local conditions and climate change rather than simply assuming that livestock will suppress the palatable species.展开更多
Temperate woodland vegetation is initially determined by spatiotemporal and historical factors,mediated by complex biotic interactions.However,catastrophic events such as disease outbreaks(e.g.,sweet chestnut blight,a...Temperate woodland vegetation is initially determined by spatiotemporal and historical factors,mediated by complex biotic interactions.However,catastrophic events such as disease outbreaks(e.g.,sweet chestnut blight,ash dieback),infestations of insect pests,and human-accelerated climate change can create canopy gaps due to systematic decline in,or loss of,tree species that was once an important part of the canopy.Resultant cascade effects have the potential to alter the composition of woodland ecosystems quickly and radically,but inherent lag times make primary research into these effects challenging.Here,we explore change in woodland vegetation at 10 sites in response to canopy opening using the Elm Decline,a rapid loss of Ulmus in woodlands across northwestern Europe~5800 years ago that coexisted alongside other stressors such as increasing human activity,as a palaeoecological analogue.For arboreal taxa,community evenness significantly decreased,within-site turnover significantly increased,and richness remained unchanged.Changes in arboreal taxa were highly site-specific but there was a substantial decline in woody climbing taxa,especially Hedera(ivy),across the majority of sites.For shrub taxa,richness significantly increased but evenness and turnover remained consistent.Interestingly,however,there was a significant increase in abundance of shrubs at 70%of sites,including Calluna(heather),Ilex(holly)and Corylus(hazel),suggesting structural change.Surprisingly,there was no change in richness,evenness or turnover for herb taxa,possibly because change was highly variable spatially.However,there was a marked uptick in the disturbance indicator Plantago(plantain).Overall,these findings suggest that woodlands with sustained reduction in,or loss of,a tree species that once formed an important part of the canopy has profound,but often spatially idiosyncratic,impacts on vegetation diversity(richness),composition(evenness),stability(turnover),and on abundance of specific taxa,especially within the shrub layer.Use of this palaeoecological analogue,which was itself complicated by cooccurring changes in human activity,provides a valuable empirical insight into possible cascade effects of similar change in canopy opening in contemporary settings,including Ash Dieback.展开更多
Background:Climate change is accelerating alterations in forest species and community composition worldwide,especially following extreme events like severe droughts and windstorms.Understanding these effects on subtro...Background:Climate change is accelerating alterations in forest species and community composition worldwide,especially following extreme events like severe droughts and windstorms.Understanding these effects on subtropical forests is crucial for conservation and forest management,but it remains unclear whether the impacts are stochastic or deterministic.Methods:We analyzed a unique dataset from a 1-ha permanent plot in a subtropical monsoon broadleaf evergreen forest in China,monitored over 26 years with six surveys from 1994 to 2020.The forest has been free from anthropogenic disturbances for over 400 years.In each survey,we measured all trees with a diameter at breast height(DBH)≥1 cm,and recorded 11 plant functional traits relating to photosynthesis,wood properties,water use,and nutrient dynamics.Using this data,we calculated species and trait dispersion,assessing short-term(~5years)and long-term(26 years)trends in species and trait composition following severe droughts and windstorm events.Results:Severe droughts,and subsequent droughts,increased both species and trait dispersion,while species composition converged,and trait dispersion remained relatively stable throughout the recovery period.Windstorm events led to increased species dispersion but decreased trait dispersion.We observed a clear directional shift in both species and trait composition under these climatic stressors,with a more pronounced increase in trait dispersion compared to species dispersion.Conclusion:In the short term(~5 years),severe droughts and windstorms increased species composition divergence,while trait composition responses varied.Over 26 years,deterministic processes mainly drove community composition changes,especially for trait composition,although stochastic processes also played a role.These findings suggest enhancing forest resilience to climatic stressors by protecting adaptive species or increasing species diversity in management practices.展开更多
Rice-fish coculture(RFC)has aroused extensive concern for its contribution to food security and resource conservation,but whether it can improve soil phosphorus(P)availability and affect microbe-mediated P turnover re...Rice-fish coculture(RFC)has aroused extensive concern for its contribution to food security and resource conservation,but whether it can improve soil phosphorus(P)availability and affect microbe-mediated P turnover remains elusive.Herein,we conducted a microcosm experiment to assess the impacts of RFC combined with(50 mg P kg^(-1)as KH2PO4)and without inorganic P addition on P fractions,P availability,and phoD-harboring bacterial community composition.The results revealed that RFC without P addition significantly improved P availability and phosphatase activity in paddy soil,while soil available P(AP),pH,and microbial biomass P(MBP)contributed to regulating P fractions.Moreover,the phoD-harboring bacterial abundance was linked to phosphatase activity,AP,total carbon(TC),and total P(TP)contents,and the ratios of TC to total nitrogen(TN)and TN to TP.We also found that the keystone taxa of phoD-harboring bacteria contributed to phosphatase production as well as organic P mineralization,thereby improving P availability.Our findings suggest that RFC without P addition is beneficial for promoting the expression of phoD-harboring bacterial functions to improve the capacity of P mineralization.Overall,our study provides insights into the responses of phoD-harboring bacterial functions for P turnover to RFC combined with and without P addition,showing the potential utilization of P resources in agricultural soil and the contribution of phosphatase activity to P acquisition in agriculture ecosystem.展开更多
Aboveground litter inputs and root exudates provide basal resources for soil communities,however,their relative contributions to soil food web are still not well understood.Here,we conducted a field manipulative exper...Aboveground litter inputs and root exudates provide basal resources for soil communities,however,their relative contributions to soil food web are still not well understood.Here,we conducted a field manipulative experiment to differentiate the effects of litter inputs and living root on nematode community composition of surface and subsoils in a young Acacia crassicapa plantation in southern China.Our results showed that both litter addition and root presence significantly enhanced soil nematode abundance by 17.3%and 35.3%,respectively.Litter addition altered nematode trophic group composition,decreased fungivore to bacterivore ratio,and enhanced maturity index and structure index,which led to a bacterial-based energy channel and a more complex food web structure.However,root presence had a limited impact on the nematode community composition and ecological indices.Despite nematodes surface assembly,soil depth did not affect nematode trophic group composition or ecological index.Our findings highlight the importance of litter inputs in shaping soil nematode community structure and regulating soil energy channel.展开更多
The elevational distributions of bacterial communities in natural mountain forests,especially along large elevational gradients,have been studied for many years.However,the distributional patterns that underlie variat...The elevational distributions of bacterial communities in natural mountain forests,especially along large elevational gradients,have been studied for many years.However,the distributional patterns that underlie variations in soil bacterial communities along small-scale elevational gradients in urban ecosystems are not yet well understood.Using Illumina MiSeq DNA sequencing,we surveyed soil bacterial communities at three elevations on Zijin Mountain in Nanjing City:the hilltop(300 m a.s.l.),the hillside(150 m a.s.l.),and the foot of the hill(0 m a.s.l.).The results showed that edaphic properties differed significantly with elevation.Bacterial community composition,rather than alpha diversity,strongly differed among the three elevations(Adonis:R2=0.12,P<0.01).Adonis and DistLM analyses demonstrated that bacterial community composition was highly correlated with soil pH,elevation,total nitrogen(TN),and dissolved organic carbon(DOC).The degree scores,betweenness centralities,and composition of keystone species were distinct among the elevations.These results demonstrate strong elevational partitioning in the distributions of soil bacterial communities along the gradient on Zijin Mountain.Soil pH and elevation together drove the smallscale elevational distribution of soil bacterial communities.This study broadens our understanding of distribution patterns and biotic co-occurrence associations of soil bacterial communities from large elevational gradients to short elevational gradients.展开更多
High-throughput sequencing technology is increasingly used in the study of nematode biodiversity.However,the annotation difference of commonly used primers and reference databases on nematode community is still unclea...High-throughput sequencing technology is increasingly used in the study of nematode biodiversity.However,the annotation difference of commonly used primers and reference databases on nematode community is still unclear.We compared two pairs of primers(3NDf/C_1132rmod,NF1F/18Sr2bR)and three databases(NT_V20200604,SILVA138/18s Eukaryota and PR2_v4.5 databases)on the determination of nematode community from four different vegetation types in Changbai Mountain,including mixed broadleaf-conifer forest,dark coniferous forest,betula ermanii Cham and alpine tundra.Our results showed that the selection of different primers and databases influenced the annotation of nematode taxa,but the diversity of nematode community showed consistent pattern among different vegetation types.Our findings emphasize that it is necessary to select appropriate primer and database according to the target taxonomic level.The difference in primers will affect the result of nematode taxa at different classification levels,so sequencing analysis cannot be used for comparison with studies using different primers.In terms of annotation effect in this study,3NDf/C_1132rmod primers with NT_v20200604 database could provide more information than other combinations at the genus or species levels.展开更多
基金supported by the Fundamental Research Funds of Chinese Academy of Forestry(Nos.CAFYBB2022SY037,CAFYBB2021ZA002 and CAFYBB2022QC002)the Basic Research Foundation of Yunnan Province(Grant No.202201AT070264).
文摘Soil microbial communities are key factors in maintaining ecosystem multifunctionality(EMF).However,the distribution patterns of bacterial diversity and how the different bacterial taxa and their diversity dimensions affect EMF remain largely unknown.Here,we investigated variation in three measures of diversity(alpha diversity,community composition and network complexity)among rare,intermediate,and abundant taxa across a latitudinal gradient spanning five forest plots in Yunnan Province,China and examined their contributions on EMF.We aimed to characterize the diversity distributions of bacterial groups across latitudes and to assess the differences in the mechanisms underlying their contributions to EMF.We found that multifaceted diversity(i.e.,diversity assessed by the three different metrics)of rare,intermediate,and abundant bacteria generally decreased with increasing latitude.More importantly,we found that rare bacterial taxa tended to be more diverse,but they contributed less to EMF than intermediate or abundant bacteria.Among the three dimensions of diversity we assessed,only community composition significantly affected EMF across all locations,while alpha diversity had a negative effect,and network complexity showed no significant impact.Our study further emphasizes the importance of intermediate and abundant bacterial taxa as well as community composition to EMF and provides a theoretical basis for investigating the mechanisms by which belowground microorganisms drive EMF along a latitudinal gradient.
基金financially supported by the National Natural Science Foundation of China(42071066)the West Light Foundation of the Chinese Academy of Sciences(2021)+1 种基金the National Key Research and Development Program of China(2023YFF1304304)the Natural Science Foundation of XizangAutonomous Region,China(XZ202201ZR0026G)。
文摘Plant community composition typically undergoes progressive changes along environmental gradients.However,most experimental studies have focused on individual communities,so it remains unclear how exogenous nutrient inputs affect the stability of plant communities along environmental gradients.Along a rainfall gradient on the northern Tibetan Plateau,we conducted an 8-year nitrogen(N)addition experiment in four alpine grasslands:alpine desert steppe(ADS),alpine steppe(AS),alpine meadow steppe(AMS),alpine meadow(AM),and we used twoway ANOVA to examine the effects of N addition on the temporal stability of these different alpine grasslands.We found that community aboveground biomass showed saturation trends in AM and AMS with increasing N gradients,while there was no change in AS and a gradual increase in ADS.The temporal stability showed different patterns of gradual decreases in ADS and AM,and a unimodal trend in AMS with increasing N gradients.However,N addition had no effect on the temporal stability of AS.Dominant species stability was the controlling factor for alpine grasslands along the transect,while the effect of asynchrony gradually increased with decreasing precipitation.These findings highlight that community composition,especially the dominant species,along the environmental gradient can mediate the effects of N inputs on community temporal stability.Thus,the conservation and restoration of the dominant species are particularly important under future scenarios of increased atmospheric N deposition.
基金supported by the National Natural Science Foundation of China(U22A20501)the National Key Research and Development Plan of China(2022YFD1500601)+4 种基金the National Science and Technology Fundamental Resources Investigation Program of China(2018FY100304)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA28090200)the Liaoning Province Applied Basic Research Plan Program,China(2022JH2/101300184)the Shenyang Science and Technology Plan Program,China(21-109-305)the Liaoning Outstanding Innovation Team,China(XLYC2008015)。
文摘Land use influences soil biota community composition and diversity,and then belowground ecosystem processes and functions.To characterize the effect of land use on soil biota,soil nematode communities in crop land,forest land and fallow land were investigated in six regions of northern China.Generic richness,diversity,abundance and biomass of soil nematodes was the lowest in crop land.The richness and diversity of soil nematodes were 28.8and 15.1%higher in fallow land than in crop land,respectively.No significant differences in soil nematode indices were found between forest land and fallow land,but their network keystone genera composition was different.Among the keystone genera,50%of forest land genera were omnivores-predators and 36%of fallow land genera were bacterivores.The proportion of fungivores in forest land was 20.8%lower than in fallow land.The network complexity and the stability were lower in crop land than forest land and fallow land.Soil pH,NH_(4)^(+)-N and NO_(3)^(–)-N were the major factors influencing the soil nematode community in crop land while soil organic carbon and moisture were the major factors in forest land.Soil nematode communities in crop land influenced by artificial management practices were more dependent on the soil environment than communities in forest land and fallow land.Land use induced soil environment variation and altered network relationships by influencing trophic group proportions among keystone nematode genera.
基金jointly funded by the National Key R&D Program of China(No.2017YFC0405205)the Major Projects on Control and Rectification of Water Body Pollution(No.2017ZX07203–004)+1 种基金the National Natural Science Foundation of China(Nos.42071118 and 41621002)supported by the TüBITAK,BIDEB program 2232.
文摘Light climate is of key importance for the growth, community composition of submerged macrophytes in lakes and, they, in turn, are affected by lake depth and the degree of eutrophication. To test the relationships between submerged macrophyte presence and the ratio of Secchi disk depth(SDD) to water depth, i.e. SDD/depth, nutrients and wind, we conducted an extensive sampling campaign in a macrophyte-dominated area of the eastern region( n = 36) in 2016 in Lake Taihu, China, and combined the data gathered with results from extensive physico-chemical monitoring data from the entire lake. We confirmed that SDD/Depth is the primary factor controlling the community composition of macrophytes and showed that plant abundance increased with increasing SDD/Depth ratio( p < 0.01), but that only SDD/Depth > 0.4 ensured growth of submerged macrophytes. Total phosphorus and total nitrogen also influenced the growth and community composition of macrophytes( p < 0.01), while Chl a was an indirectly affecting factor by reducing underwater light penetration. Wave height significantly influenced plant abundance( p < 0.01), whereas it had little effect on the biomass( p > 0.05). The key to restore the macrophyte beds in the lake is to reduce the nutrient loading. A decrease of the water level may contribute as well in the shallow bays but will not bring plants back in the main part of the lake. As the tolerance of shade and nutrients varied among the species studied, this should be taken into account in the restoration of lakes by addition of plants.
基金supported by the National Natural Science Foundation of China (Grant No.31500443)Fujian Province Department of Education Foundation (Grant No.JA15178)
文摘Seasonal shifts play an important role in soil microbial community composition. This study examined the hypothesis that soil microbial community structure would vary with seasonal shifts in the Wuyi Mountains in Southeast China, and that two representative tree species （Castanopisi carlesii and Cunninghamia lanceolata） may have different soil microbial community composition. Phospholipids fatty acid analysis （PLFA） of seasonal shifts and was used to assess the effect vegetation types on soil microbial community structure. A total of 22 different PLFAs were identified from all the soil samples. The bacterial PLFAs accounted for 62.37% of the total PLFAs, followed by fungi （28.94%）, and the minimum was actinomycetes （6.41%）. Overall, the level of PLFAs in C. carlesii soil was greater than those in C. lanceolata soil, and significant differences were observed in some seasons. The amounts of total, bacteria, actinomycic and fungal PLFAs significantly changed with the seasons and followed a sequence order （summer 〉 autumn 〉 spring 〉 winter）. The bacteria/fungi PLFAs and G （＋）/G （-） PLFAs of two vegetation types also changed with the seasons and the ratios in summer and autumn were higher than those in spring and winter. The correlation analysis of microbial PLFAs and soil physicochemical properties showed that the total, bacteria, fungal, actinomycic, G （＋） and G （-） PLFAs were significantly positive correlation with TOC, TN, TP, TK and moisture content. We concluded that the seasonal shifts and vegetation types affect soil microbial community composition by changing the soil physicochemical properties.
基金Supported by the Key Program of National Natural Science Foundation of China (No. 90711006)
文摘Phytoplankton pigment patterns and community composition were investigated in the northern South China Sea using high-performance liquid chromatography and the CHEMTAX software from February 11 to 23, 2009. We recognized four different vertical distribution patterns of pigments: chlorophyll a (Chl a)-like type, divinyl chlorophyll a (DV Chl a) type, even distribution type, and surface type. The average value of ratios of accessory photo-protective pigments (APP) to accessory photo-synthetic pigments was 0.89±0.63 in the upper 50 m and 0.16±0.06 below 50 m depth. With increasing depth, APP decreased and photo-synthetically active radiation was attenuated. There was an obvious succession in the phytoplankton community from inshore to the open sea. Diatoms were dominant in the inshore region, while pelagophytes, Prochlorococcus, cyanobacteria and prymnesiophytes were dominant in the open sea. The vertical distribution of phytoplankton also differed greatly from inshore to the open sea. In the coastal and shelf region, diatoms were important components in the whole water column. Cyanobacteria also had a high abundance at the Subsurface Chlorophyll a Maxima (SCM) in the shelf region. In the slope and open sea, Prochlorococcus and cyanobacteria were important groups above the SCM, while pelagophytes dominated below the SCM.
基金This study was funded by the Open Project of Key Laboratory of the Ministry of Agriculture and Rural Affairs,China(KLFAW201705)the National Natural Science Foundation of China(31870501)+1 种基金the Technological Achievements Cultivation Project of Hubei Academy of Agricultural Sciences(2017CGPY01)the Key Project of Technological Innovation in Hubei Province,China(2018ABA091).
文摘Soil nematode communities can provide valuable information about the structure and functions of soil food webs,and are sensitive to agricultural practices,including short-term straw incorporation.However,currently,such effects under longterm straw incorporation conditions at different fertility levels are largely unknown.Thus,we conducted a 13-year ongoing experiment to evaluate the effects of long-term straw incorporation on the structure and functions of the soil food web in low and high fertility soils through analyzing its effects on nematode communities,food web indices and metabolic footprints.Four treatments were included:straw removal(–S)under non-fertilized(–NPK)or fertilized(+NPK)conditions;and straw incorporation(+S)under–NPK or+NPK conditions.Soil samples from a 0–20 cm depth layer were collected when wheat and rice were harvested.Compared with straw removal,straw incorporation increased the abundances of total nematodes,bacterivores,plant-parasites and omnivores-predators,as well the relative abundances of omnivores-predators with increases of 73.06,89.29,95.31,238.98,and 114.61%in–NPK soils and 16.23,2.23,19.01,141.38,and 90.23%in+NPK soils,respectively.Regardless of sampling times and fertilization effects,straw incorporation increased the diversity and community stability of nematodes,as indicated by the Shannon-Weaver diversity index and maturity index.Enrichment and structure index did not show significant responses to straw incorporation,but a slight increase was observed in the structure index.The analysis of nematode metabolic footprints showed that straw incorporation increased the plant-parasite footprint and structure footprint by 97.27 and 305.39%in–NPK soils and by 11.29 and 149.56%in+NPK soils,but did not significantly influence enrichment,bacterivore and fungivore footprints.In conclusion,long-term straw incorporation,particularly under a low fertility level,favored the soil nematodes and regulated the soil food web mainly via a top-down effect.
基金funded by the National Natural Science Foundation of China(Nos.31700542,32071745,31870602,31800519 and 31901295)Program of Sichuan Excellent Youth Sci-Tech Foundation(No.2020JDJQ0052)the National Key Research and Development Program of China(Nos.2016YFC0502505 and 2017YFC0505003)。
文摘Background:Soil fungi play crucial roles in ecosystem functions.However,how snow cover change associated with winter warming affects soil fungal communities remains unclear in the Tibetan forest.Methods:We conducted a snow manipulation experiment to explore immediate and legacy effects of snow exclusion on soil fungal community diversity and composition in a spruce forest on the eastern Tibetan Plateau.Soil fungal communities were performed by the high throughput sequencing of gene-fragments.Results:Ascomycota and Basidiomycota were the two dominant fungal phyla and Archaeorhizomyces,Aspergillus and Amanita were the three most common genera across seasons and snow manipulations.Snow exclusion did not affect the diversity and structure of soil fungal community in both snow-covered and snow-free seasons.However,the relative abundance of some fungal communities was different among seasons.Soil fungal groups were correlated with environmental factors(i.e.,temperature and moisture)and soil biochemical variables(i.e.,ammonium and enzyme).Conclusions:These results suggest that the season-driven variations had stronger impacts on soil fungal community than short-term snow cover change.Such findings may have important implications for soil microbial processes in Tibetan forests experiencing significant decreases in snowfall.
基金the National Natural Science Foundation of China(No.91958103)the Science&Technology Basic Resources Investigation Program of China(No.2017FY100802)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19060401)。
文摘The oxygen minimum zones(OMZs)are globally expanding,yet the variation pattern of microbial communities related to dissolved oxygen levels remain unclear.Spatial variability of bacterial diversity and community composition(repre sented by 16 S rRNA)of six stations was investigated within the water column in the seamount area of Tropical Western Pacific Ocean(TWPO)in May 2019.The seawater has dissolved oxygen(DO)concentration of 3.01-6.68 mg/L and the core of the oxygen minimum zones was located between the depths of 650 m and 1750 m.The bacterial alpha-diversity showed unimodal pattern with the decreasing DO with depths and peaked in the upper oxycline(UO)of OMZs.The bacterial community structure of the mixed layer(ML)and the bottom layer clustered and separated from each other,while those of UO and the OMZ core(OM)clustered and overlapped.Overall,bacterial community composition transitioned from being Alphaproteobacteria and Gammaproteobacteria-dominant in ML to being Gammaproteobacteria and Nitrososphaeria/Deltaproteobacteria-dominant in UO and OM,and then changed to being Clostridia and unidentified Actinobacteria-dominant in the bottom layer.Moreover,both bacterial alpha-diversity and the abundant classes fitted varying sectioned functions with DO.The DO solely explained 40.37%of the variation of bacterial community composition among layers(P<0.001).The predicted function profiling showed that the water column was predominant by chemoheterotrophy,cyanobacteria,and photoautotrophy in ML,by chemoheterotrophy and nitrate/sulfide cycling in UO and OM,and by chemoheterotrophy and ferme ntation in the bottom layer.Our findings revealed the DO-associated variation in bacterial diversity and community composition,and help to clarify the potential responses of microbes and their involved biogeochemical processes to the expansion and intensification of OMZs.
基金Supported by the National Key Technology R&D Program of China(No.2014BAC09B02)the National Water Pollution Control and Management Technology Major Projects(No.2012ZX07101-002)the High-Level Scientific Research Foundation for the Introduction of Talent(No.E07016043)
文摘We characterized variations in bacterioplankton community composition(BCC) in mesocosms subject to three different treatments. Two groups contained fish(group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-d period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis(DGGE) and real-time quantitative PCR(q PCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly diff erent between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected in C. carpio mesocosms. The redundancy analysis(RDA) result demonstrated that the BCC was closely related to the bottom-up(total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces(biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa(heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem.
基金Funded by the Natural Science Foundation of China (No.50178070)the Natural Science Foundation of Chongqing (Nos. 8091 and 7136)
文摘To understand the potential impact of the Three Gorges Reservoir on the aquatic ecosystem after the damming of the Yangtze River,we studied the community composition and temporal abundance distribution of algae in two types of water bodies:a segment of the Jialing River near its confluence with the Yangtze River as an example of the river-lake type,and Shuanglong Lake in Chongqing as an example of the lake type.In total,107 species belonging to 58 genera of 7 phyla were identified in the study area of the Jialing River,dominated by three groups with 49.5% diatoms,29.0% chlorophytes,and 11.4% cyanobacteria in the community composition.There were 122 species belonging to 66 genera of 8 phyla in Shuanglong Lake,dominated by the same three groups with 19.7% diatoms,48.4% chlorophytes,and 22.2% cyanobacteria.The densities of total algae and individual dominant groups were all much higher in the lake.More species of diatoms were found in the river-lake segment;whereas more chlorophyte species and cyanobacteriaum species were in the lake.There were 17 dominant species including 8 diatoms,4 chlorophytes,3 cyanobacteria and 2 cryptophytes in the river-lake segment,and 21 species in the lake,including 2 diatoms,9 chlorophytes,6 cyanobacteria,3 cryptophytes and a dinoflagellate.In eutrophic conditions,chlorophytes and cyanobacteria may proliferate in a lake-type area and diatoms may cause algal bloom in a relatively faster-flow lake-river type area.
基金The Qinghai Province Key Research&Development and Transformation Plan Project in 2023(2023-NK-133)The Special Fund for Innovation Capacity Construction of Scientific Research Institutions in Guizhou Province(QIANKEHEFUQI(2021)2,QIANKEHEFUQI[2024]010)。
文摘Objectives:To investigate the diversity and community composition of endophytes in Sinopodophyllum hexandrum(Royle)Ying.Methods:S.hexandrum samples(n=15)were collected at five sites on the Tibetan Plateau.High quality sequences from high-throughput sequencing were clustered into operational taxonomic units(OTUs)by Clustering and Classification Inference with U-Statistics,and the OTUs were further divided into different genera according to Ribosomal Database Project classification.Alpha and beta diversity analyses were conducted to explore community diversity and composition.Results:A total of 1221 OTUs were obtained,representing 133 genera(with 98 specific to genus).The QJ and XH sampling sites had the most(n=67)and fewest(n=36)genera,respectively.The dominant fungi at the DT,LD,QJ and XH sites were Ascomycota,while the dominant fungi at the BX site were Basidiomycota.Tetracladium,Exophiala and Pseudogymnoascus showed obvious host preference in all samples.The dominant fungi in the three provinces were Tetracladium,Penicillium,and Cantharellales,respectively.The Shannon-Weiner diversity indices of the 15 samples ranged from 0.48 to 3.10.Endophytic fungi were clustered into three branches based on geographical location.Conclusion:Our findings provide a research basis for the exploitation and utilization of national medicinal plants with abundant microbial resources.
基金National Natural Science Foundation of China:Changes of Ras Homolog Gene Family Member A/Rho-associated Coiled-coil Kinase Signaling Pathway in Liver-Stomach Disharmony Functional Dyspepsia Rats and Intervention Mechanism of Simo Tang (No. 81803896)the Role of Gut Microbiota-diaminopimelic Acid Nucleotide-binding and Oligomerization Domain1-receptorinteracting Protein 2 Signal Pathway in Severe Process of Acute Pancreatitis and the Intervention Mechanism of Qingxia Therapy (No. 81873156)Research Project of Liaoning Provincial Department of Education:the Role of Mitochondria-Derived Reactive Oxygen Species Mediated Autophagy Activation in Myocardial Injury in Sepsis (No. LZ2020036)。
文摘OBJECTIVE: To investigate composition of gut microbial community in a rat model of functional dyspepsia(FD) and to explore the interventional effects of Simo Tang(四磨汤, SMT). METHODS: A rat model of FD was established through the tail-clamping stimulation method. The rat model of FD was assessed by the state of rats, their weight, sucrose preference rate, and intestinal propulsion rate. The DNA was extracted from stool samples after treatment with SMT. Amplified polymerase chain reaction(PCR) products of the 16S r DNA were sequenced using Novase Q6000 after construction of libraries. Composition of gut microbial community in the stool samples was determined and analyzed by cluster analysis, bioinformatic analysis, and analysis of α-diversity and β-diversity.RESULTS: The rat model of FD was successfully established using the tail-clamping stimulation method. The statistical results of cluster analysis of operational taxonomic units(OTUs) showed that the relative abundance of OTUs in the FD group was the lowest, while it was the highest in the normal(N) group. The composition of microbiome in the four groups was similar at phyla level. Compared with the FD group, the abundance of Firmicutes was downregulated, and the abundance of Proteobacteria and Bacteroidetes was upregulated in the Simo Tang(SMT) and high-dose Simo Tang(SMT.G) groups. The ratio of Bacteroidetes/Firmicutes was also elevated. According to the analysis of α-diversity and β-diversity, the abundance of flora in FD rats was significantly reduced. The treatment using SMT appeared beneficial to improve the diversity of flora. SMT could improve the intestinal flora in FD rats. The results showed that FD rats had intestinal flora imbalance, and species diversity increased. The results suggested that SMT could regulate the disorders of intestinal flora caused by FD. CONCLUDIONS: SMT could restore gut homeostasis and maintain gut flora diversity by modulating the gut microbiota and its associated metabolites in rats, thereby treating gastrointestinal diseases.
基金financially supported by grants from the National Natural Science Foundation of China(32101315 and 32101326)the National Key R&D Program of China(2021YFE0112400)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research Program,China(2019QZKK0307)the HighLevel Talent Research Start-Up Project of Chongqing Technology and Business University,China(950319097)the Scientific and Technological Research Program of Chongqing Municipal Education Commission,China(KJQN202100827)。
文摘When the dominant species in a plant community are palatable,many believe that large herbivores will reduce the dominant species and promote the proportion of previously suppressed species.However,this view may not always hold true.We conducted a 4-year yak grazing experiment on the Qinghai-Tibet Plateau and tracked the plant compositions of the rotational grazing(RG)and grazing exclusion(GE)grasslands during the four years.The results showed that in the absence of yaks under GE,the plant community was dominated by two palatable species,Kobresia pygmaea and Stipa capillata,due to their small leaf area and rapid growth strategy.The presence of yaks under RG significantly inhibited S.capillata and over half of the forbs,while the proportion of K.pygmaea increased and it became the absolute dominant species,contradicting the view that large herbivores inhibit palatable species.Interannually,the dominance of K.pygmaea under RG decreased in the dry year,leading to an increase in the dominance of the other eight species.Under GE,the dominance of K.pygmaea declined notably in the dry year,while S.capillata and seven other forbs increased substantially.Overall,these results suggest that K.pygmaea is grazing-tolerant but not drought-tolerant,whereas the other eight species are drought-tolerant but not grazingtolerant.At the community level,community composition shifts resulting from succession after grazing exclusion exceeded those caused by drought,drought tends to induce community species turnover while grazing tends to induce species abundance variations.In summary,our conclusions remind ranch managers that when considering the impact of livestock on plant community composition,they should factor in local conditions and climate change rather than simply assuming that livestock will suppress the palatable species.
文摘Temperate woodland vegetation is initially determined by spatiotemporal and historical factors,mediated by complex biotic interactions.However,catastrophic events such as disease outbreaks(e.g.,sweet chestnut blight,ash dieback),infestations of insect pests,and human-accelerated climate change can create canopy gaps due to systematic decline in,or loss of,tree species that was once an important part of the canopy.Resultant cascade effects have the potential to alter the composition of woodland ecosystems quickly and radically,but inherent lag times make primary research into these effects challenging.Here,we explore change in woodland vegetation at 10 sites in response to canopy opening using the Elm Decline,a rapid loss of Ulmus in woodlands across northwestern Europe~5800 years ago that coexisted alongside other stressors such as increasing human activity,as a palaeoecological analogue.For arboreal taxa,community evenness significantly decreased,within-site turnover significantly increased,and richness remained unchanged.Changes in arboreal taxa were highly site-specific but there was a substantial decline in woody climbing taxa,especially Hedera(ivy),across the majority of sites.For shrub taxa,richness significantly increased but evenness and turnover remained consistent.Interestingly,however,there was a significant increase in abundance of shrubs at 70%of sites,including Calluna(heather),Ilex(holly)and Corylus(hazel),suggesting structural change.Surprisingly,there was no change in richness,evenness or turnover for herb taxa,possibly because change was highly variable spatially.However,there was a marked uptick in the disturbance indicator Plantago(plantain).Overall,these findings suggest that woodlands with sustained reduction in,or loss of,a tree species that once formed an important part of the canopy has profound,but often spatially idiosyncratic,impacts on vegetation diversity(richness),composition(evenness),stability(turnover),and on abundance of specific taxa,especially within the shrub layer.Use of this palaeoecological analogue,which was itself complicated by cooccurring changes in human activity,provides a valuable empirical insight into possible cascade effects of similar change in canopy opening in contemporary settings,including Ash Dieback.
基金supported by National Natural Science Foundation of China(Nos.42130506,42071031)the Special Technology Innovation Fund of Carbon Peak and Carbon Neutrality in Jiangsu Province(No.BK20231515)。
文摘Background:Climate change is accelerating alterations in forest species and community composition worldwide,especially following extreme events like severe droughts and windstorms.Understanding these effects on subtropical forests is crucial for conservation and forest management,but it remains unclear whether the impacts are stochastic or deterministic.Methods:We analyzed a unique dataset from a 1-ha permanent plot in a subtropical monsoon broadleaf evergreen forest in China,monitored over 26 years with six surveys from 1994 to 2020.The forest has been free from anthropogenic disturbances for over 400 years.In each survey,we measured all trees with a diameter at breast height(DBH)≥1 cm,and recorded 11 plant functional traits relating to photosynthesis,wood properties,water use,and nutrient dynamics.Using this data,we calculated species and trait dispersion,assessing short-term(~5years)and long-term(26 years)trends in species and trait composition following severe droughts and windstorm events.Results:Severe droughts,and subsequent droughts,increased both species and trait dispersion,while species composition converged,and trait dispersion remained relatively stable throughout the recovery period.Windstorm events led to increased species dispersion but decreased trait dispersion.We observed a clear directional shift in both species and trait composition under these climatic stressors,with a more pronounced increase in trait dispersion compared to species dispersion.Conclusion:In the short term(~5 years),severe droughts and windstorms increased species composition divergence,while trait composition responses varied.Over 26 years,deterministic processes mainly drove community composition changes,especially for trait composition,although stochastic processes also played a role.These findings suggest enhancing forest resilience to climatic stressors by protecting adaptive species or increasing species diversity in management practices.
基金supported by the Key-Area Research and Development Program of Guangdong Province,China(No.2021B0202030002)the Science and Technology Planning Project of Guangdong Province,China(No.2019B030301007)+2 种基金the Guangdong Provincial Special Project of Rural Revitalization Strategy,China(No.(2021)12)the Joint Team Project of Guangdong Laboratory for Lingnan Modern Agriculture,China(No.NT2021010)the Innovation Team Construction Project of Modern Agricultural Industry Technology Systems of Guangdong Province,China(No.2022KJ105).
文摘Rice-fish coculture(RFC)has aroused extensive concern for its contribution to food security and resource conservation,but whether it can improve soil phosphorus(P)availability and affect microbe-mediated P turnover remains elusive.Herein,we conducted a microcosm experiment to assess the impacts of RFC combined with(50 mg P kg^(-1)as KH2PO4)and without inorganic P addition on P fractions,P availability,and phoD-harboring bacterial community composition.The results revealed that RFC without P addition significantly improved P availability and phosphatase activity in paddy soil,while soil available P(AP),pH,and microbial biomass P(MBP)contributed to regulating P fractions.Moreover,the phoD-harboring bacterial abundance was linked to phosphatase activity,AP,total carbon(TC),and total P(TP)contents,and the ratios of TC to total nitrogen(TN)and TN to TP.We also found that the keystone taxa of phoD-harboring bacteria contributed to phosphatase production as well as organic P mineralization,thereby improving P availability.Our findings suggest that RFC without P addition is beneficial for promoting the expression of phoD-harboring bacterial functions to improve the capacity of P mineralization.Overall,our study provides insights into the responses of phoD-harboring bacterial functions for P turnover to RFC combined with and without P addition,showing the potential utilization of P resources in agricultural soil and the contribution of phosphatase activity to P acquisition in agriculture ecosystem.
基金the NSFC-Henan Joint Fund(U1804101,U1904204)Henan Key Scientific and Technological Project(192102110160)+1 种基金the National Natural Science Foundation of China(31800405)Innovation Scientists and Technicians Troop Construction Projects of Henan Province.
文摘Aboveground litter inputs and root exudates provide basal resources for soil communities,however,their relative contributions to soil food web are still not well understood.Here,we conducted a field manipulative experiment to differentiate the effects of litter inputs and living root on nematode community composition of surface and subsoils in a young Acacia crassicapa plantation in southern China.Our results showed that both litter addition and root presence significantly enhanced soil nematode abundance by 17.3%and 35.3%,respectively.Litter addition altered nematode trophic group composition,decreased fungivore to bacterivore ratio,and enhanced maturity index and structure index,which led to a bacterial-based energy channel and a more complex food web structure.However,root presence had a limited impact on the nematode community composition and ecological indices.Despite nematodes surface assembly,soil depth did not affect nematode trophic group composition or ecological index.Our findings highlight the importance of litter inputs in shaping soil nematode community structure and regulating soil energy channel.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB15010101)the National Natural Science Foundation of China(41907039)the China Biodiversity Observation Networks(Sino BON).
文摘The elevational distributions of bacterial communities in natural mountain forests,especially along large elevational gradients,have been studied for many years.However,the distributional patterns that underlie variations in soil bacterial communities along small-scale elevational gradients in urban ecosystems are not yet well understood.Using Illumina MiSeq DNA sequencing,we surveyed soil bacterial communities at three elevations on Zijin Mountain in Nanjing City:the hilltop(300 m a.s.l.),the hillside(150 m a.s.l.),and the foot of the hill(0 m a.s.l.).The results showed that edaphic properties differed significantly with elevation.Bacterial community composition,rather than alpha diversity,strongly differed among the three elevations(Adonis:R2=0.12,P<0.01).Adonis and DistLM analyses demonstrated that bacterial community composition was highly correlated with soil pH,elevation,total nitrogen(TN),and dissolved organic carbon(DOC).The degree scores,betweenness centralities,and composition of keystone species were distinct among the elevations.These results demonstrate strong elevational partitioning in the distributions of soil bacterial communities along the gradient on Zijin Mountain.Soil pH and elevation together drove the smallscale elevational distribution of soil bacterial communities.This study broadens our understanding of distribution patterns and biotic co-occurrence associations of soil bacterial communities from large elevational gradients to short elevational gradients.
基金supported by the National Natural Science Foundation of China(Grant No.U20A2083),the K.C.Wong Education Foundation(Grant No.GJTD-2019-10)China Postdoctoral Science Foundation(Grant No.2021T140697).
文摘High-throughput sequencing technology is increasingly used in the study of nematode biodiversity.However,the annotation difference of commonly used primers and reference databases on nematode community is still unclear.We compared two pairs of primers(3NDf/C_1132rmod,NF1F/18Sr2bR)and three databases(NT_V20200604,SILVA138/18s Eukaryota and PR2_v4.5 databases)on the determination of nematode community from four different vegetation types in Changbai Mountain,including mixed broadleaf-conifer forest,dark coniferous forest,betula ermanii Cham and alpine tundra.Our results showed that the selection of different primers and databases influenced the annotation of nematode taxa,but the diversity of nematode community showed consistent pattern among different vegetation types.Our findings emphasize that it is necessary to select appropriate primer and database according to the target taxonomic level.The difference in primers will affect the result of nematode taxa at different classification levels,so sequencing analysis cannot be used for comparison with studies using different primers.In terms of annotation effect in this study,3NDf/C_1132rmod primers with NT_v20200604 database could provide more information than other combinations at the genus or species levels.
