Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how woul...Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.展开更多
The environmental impacts of acid mine drainage(AMD)from open-pit mining are profoundly detrimental,yet knowledge about its effects on paddy soil microbial communities,especially at greater depths,remains limited.In t...The environmental impacts of acid mine drainage(AMD)from open-pit mining are profoundly detrimental,yet knowledge about its effects on paddy soil microbial communities,especially at greater depths,remains limited.In this investigation,we compared soils affected by AMD versus unaffected soil depth profiles in terms of bacterial diversity and community assembly.The profiles in AMD-polluted soils exhibited tight geochemical gradients,characterized by increased acidity,SO_(4)^(2-),NO_(3)^(-),and heavy metal content compared to unpolluted soils.Notably,AMD significantly diminished soil bacterial biodiversity.A depthwise analysis showed distinct microbial stratification,with certain bacteria like Candidatus_Solibacter and Candidatus_Koribacter predominated in polluted soils,while others like Haliangium and Nitrospira were more prevalent in control soils.Interestingly,despite variable soil conditions,predictedmetabolic pathways,particularly those involving carbon,nitrogen,and sulfur,showed relative stability.AMD pollution induced the upregulation of methylcoenzyme M reductase and sulfate reductase genes.Bacterial communities were more responsive to pH and nutrient content rather than heavy metals,with pH and SO_(4)^(2-)being the primary drivers of microbial diversity and distribution.Additionally,pHwas identified as the most significant influence on the predicted methane,sulfur,and nitrogen metabolism.Furthermore,deterministic processes played a more significant role in community assembly of polluted soils,while heterogeneous selection gained importance with increasing depth in control soils.Additionally,microbial co-occurrences,particularly positive interactions,were more prevalent in the polluted soils with reduced network modularity and keystone taxa.These findings offer insights into sustaining microbial diversity in extreme environments.展开更多
Understanding plant community assembly is crucial for effective ecosystem conservation and restoration.The ecological filter framework describes community assembly as a process shaped by dispersal,environmental,and bi...Understanding plant community assembly is crucial for effective ecosystem conservation and restoration.The ecological filter framework describes community assembly as a process shaped by dispersal,environmental,and biotic filters.Additionally,functional traits and phylogenetic relationships are increasingly recognized as important factors influencing species coexistence and community structure.However,both the ecological filter framework and the roles of functional traits and phylogeny in community assembly remain underexplored in the Algerian steppes—particularly in the El Bayadh region,where ongoing vegetation degradation threatens ecosystem stability.This study applied Hierarchical Modeling of Species Communities(HMSC)as an integrative approach to assess how ecological filters influence plant community assembly in the El Bayadh steppe and to evaluate the roles of functional traits and phylogenetic relationships in this process.Environmental data—including soil properties,topography,precipitation,and land use types(grazing and exclosure)—were collected across 50 plots in April and October,2023,along with functional traits from 24 species.These traits include root length,leaf area,specific leaf area,clonality,life history,and seed mass.HMSC results revealed that soil properties and precipitation were the primary drivers of community structure,while sand height and elevation had a moderate influence.In contrast,competition and grazing played relatively minor roles.Species responses to environmental covariates were heterogeneous:soil fertility and texture had mixed effects,benefiting some species while limiting others;sand encroachment and precipitation variability generally had negative impacts,whereas grazing exclusion favored many species.A weak phylogenetic signal was recorded,indicating that community assembly was driven more by environmental filtering than by shared evolutionary history.Functional trait responses to environmental variation reflected plant strategies that balanced resource acquisition and conservation.Specifically,seed mass,leaf area,and root length increased under higher soil moisture and nutrient availability but declined in response to salinity,precipitation variability,and sand height.Clonality and perennial life history traits enhanced the survival of plant species under harsh conditions.Overall,this study provides a holistic understanding of community assembly processes in the El Bayadh steppe and offers valuable insights for ecosystem management and restoration in arid and degraded ecosystem environments.展开更多
As one of the important wintering areas along the East Asian-Australasian Flyway,wetlands in the Yangtze River floodplain face threats from land-use changes,yet its effects on wintering waterbirds at the landscape lev...As one of the important wintering areas along the East Asian-Australasian Flyway,wetlands in the Yangtze River floodplain face threats from land-use changes,yet its effects on wintering waterbirds at the landscape level remain understudied,impeding conservation practice.Here,using survey data collected across 14 inland lakes in Jiangsu Province in 2022,we calculated wintering waterbirds diversity(taxonomic,functional,phylogenetic)and assembly patterns(MPD/MNTD of functional and phylogenetic).Then,we interpreted satellite imagery of lake areas and buffer zones(5 km),and partitioned them into three land-use and landscape index categories(anthropogenic,ecological,and lake landscape).Finally,we employed multiple linear regression and hierarchical partitioning to explain the influence of landscape scales on wintering waterbird communities.Our results showed that the diversity and assembly of regional wintering waterbird communities tended to be consistent across taxonomic,functional,and phylogenetic dimensions.The standardized diversity indices indicated that functional assembly of communities tends to be clustered at both local and regional scale.In contrast,the phylogenetic structure showed a predominantly overdispersed pattern in most lakes at the local scale,while neutral processes dominated at the regional scale.Modeling showed that selected variables explained waterbird diversity and assembly well.Lake fragmentation increased species evenness but reduced other diversity indices,while landscape evenness was negatively associated with functional and phylogenetic assembly.Among anthropogenic factors,aquaculture ponds and impervious surfaces reduced all diversity dimensions,whereas cropland connectivity enhanced phylogenetic diversity.These factors had consistent effects on community assembly.For ecological variables,grassland area enhanced functional and phylogenetic diversity but led to more clustered functional assembly.Overall,maintaining the integrity and connectivity of lakes and their surrounding landscapes is essential for sustaining waterbird diversity and guiding wetland restoration.展开更多
Spatial and environmental processes are two ecological processes that have attracted considerable attention in plant community assembly,depending on sampling scale and life history.However,the processes that determine...Spatial and environmental processes are two ecological processes that have attracted considerable attention in plant community assembly,depending on sampling scale and life history.However,the processes that determine community assembly have not been studied in the karst region of southwest China.In this study,a 25-ha(500 m×500 m)monitoring plot within the subtropical climax forest in the karst region was established and canonical correspondence analysis was used to reveal the effects of topography and soil on the spatial patterns of tree community assembly.Our study suggests that spatial processes dominate species composition and the combined effects of spatial and environmental processes play an important role.Overall interpretation rate increases with enlarging the sampling scale.However,the pattern of variation partitioning was similar in different life stages.Environmental variables significantly affected species composition at different sampling sizes and life histories and had a higher interpretation rate of species composition on larger s ampling sizes.Topographic wetness index was the most important variable to explain species composition of the environmental variables.These results suggest that it is necessary to consider the relative importance of environmental and spatial factors on community assembly to better understand,conserve,and manage subtropical karst forests.展开更多
The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evo...The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.展开更多
Lake mixing influences aquatic chemical properties and microbial community composition,and thus,we hypothesized that it would alter microbial community assembly and interac-tion.To clarify this issue,we explored the c...Lake mixing influences aquatic chemical properties and microbial community composition,and thus,we hypothesized that it would alter microbial community assembly and interac-tion.To clarify this issue,we explored the community assembly processes and cooccurrence networks in four seasons at two depths(epilimnion and hypolimnion)in a mesotrophic and stratified lake(Chenghai Lake),which formed stratification in the summer and turnover in the winter.During the stratification period,the epilimnion and hypolimnion went through contrary assembly processes but converged to similar assembly patterns in the mixing pe-riod.In a highly homogeneous selection environment,species with low niche breadth were filtered,resulting in decreased species richness.Water mixing in the winter homogenized the environment,resulting in a simpler microbial cooccurrence network.Interestingly,we observed a high abundance of the cyanobacterial genus Planktothrix in the winter,proba-bly due to nutrient redistribution and Planktothrix adaptivity to the winter environment in which mixing played important roles.Our study provides deeper fundamental insights into how environmental factors influence microbial community structure through community assembly processes.展开更多
Predicting species abundance is one of the most fundamental pursuits of ecology.Combining the information encoded in functional traits and metacommunities provides a new perspective to predict the abundance of species...Predicting species abundance is one of the most fundamental pursuits of ecology.Combining the information encoded in functional traits and metacommunities provides a new perspective to predict the abundance of species in communities.We applied a community assembly via trait selection model to predict quadrat-scale species abundances using functional trait variation on ontogenetic stages and metacommunity information for over 490 plant species in a subtropical forest and a lowland tropical forest in Yunnan,China.The relative importance of trait-based selection,mass effects,and stochasticity in shaping local species abundances is evaluated using different null models.We found both mass effects and trait selection contribute to local abundance patterns.Trait selection was detectable at all studied spatial scales(0.04e1 ha),with its strength stronger at larger scales and in the subtropical forest.In contrast,the importance of stochasticity decreased with spatial scale.A significant mass effect of the metacommunity was observed at small spatial scales.Our results indicate that tree community assembly is primarily driven by ontogenetic traits and metacommunity effects.Our findings also demonstrate that including ontogenetic trait variation into predictive frameworks allows ecologists to infer ecological mechanisms operating in community assembly at the individual level.展开更多
Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community asse...Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community assembly in virgin and aging MP plastispheres across different habitats is poorly understood.This study aims to assess the variations in bacterial community assembly across different niches and habitats with an in situ ex-periment,in which constructed forest wetland(FW),natural lake wetland(LW),and lotus pond wetland(LP)were habitats,and plastispheres of virgin and aging low-density polyethylene(LDPE)MPs,as well as surround-ing wetland soils were niches.Significant niche-related differences in bacterial communities were observed,with lower diversity and enrichment of potential plastic-degrading bacteria in the plastisphere than in the soil bacterial communities.Furthermore,habitat-related differences exerted a more pronounced influence on the beta-diversity patterns of the bacterial communities.The linear regression analyses indicated that the local species pool con-tributed more to bacterial community assembly in the LW wetland,whereas the relative abundance of species was the primary factor in the LP wetland.The null model analysis indicated that plastisphere bacterial communi-ties were predominantly driven by the stochastic process,with a more deterministic assembly observed in the LP wetland and soil bacterial communities.Additionally,the primary ecological process shaping plastisphere com-munities shifted from drift in the virgin LDPE to homogenising dispersal in the aging LDPE.This study provides new insights into the fate and ecological impacts of MPs in wetlands,thereby facilitating the effective regulations of plastic pollution.展开更多
Background Identifying the processes that govern community assembly along elevational gradients has been a central theme in ecology,especially in montane ecosystems where abundant species and strong turnover are prese...Background Identifying the processes that govern community assembly along elevational gradients has been a central theme in ecology,especially in montane ecosystems where abundant species and strong turnover are present.However,our understanding of how the relative importance of deterministic and stochastic processes varies along elevational gradients remains limited.Here,we compiled a rigorously curated dataset of elevational distributions of 734 breeding bird species across the Hengduan Mountains in China to assess the dominant underlying mechanisms of bird community assembly at both intra-community and inter-community scales across four elevation zones:low,middle,subalpine,and alpine.Results At the intra-community scale,homogeneous dispersal played a pivotal role in driving community assembly of breeding birds across the Hengduan Mountains.Deterministic processes became more influential with increasing elevation,whereas stochastic processes prevailed in low,middle,and subalpine zones.At inter-community scale,assemblages from different elevation zones were more differentiated by dispersal limitation.Non-Passeriformes experienced more obvious influence of homogeneous dispersal but were less subject to dispersal limitation compared to Passeriformes.Conclusions Our findings highlight the role of stochastic processes in shaping biotic communities in montane ecosystems,but this effect is scale-dependent.The transition from stochastic to deterministic processes along elevational gradients suggests that environmental factors become more influential at higher elevations.Species dispersal ability may affect the relative importance of these two processes shaping community assembly.展开更多
Background Understanding the temporal development of community assembly processes is essential for assessing the recovery of degraded ecosystems after restoration.Community development in restored streams is often slo...Background Understanding the temporal development of community assembly processes is essential for assessing the recovery of degraded ecosystems after restoration.Community development in restored streams is often slow or absent,due to inadequate restoration,catchment-scale pressures,and/or colonisation barriers.Recovery processes involve three key filters:dispersal,environmental conditions and biotic interactions.Dispersal is critical for initial colonisation,while environmental conditions influence successful population establishment.Lastly,as available niches fill,biotic interactions,such as competition,gain importance.Despite the presence of many theories on how these three filters interact during community assembly,they have rarely been investigated simultaneously.Our detailed species-and site-specific approach allowed us to analyse the three filters in a hierarchical analysis.We assessed the effect of the three filters,by examining benthic invertebrate communities at 20 sites in the Boye catchment(Western Germany).The Boye and most of its tributaries were used as open sewers for a century,i.e.they were concrete channels transporting untreated sewage before gradual restoration was started in the 1990s.The bank reinforcements and concrete beds were removed,while riparian vegetation was left to natural succession.Accordingly,the sites were grouped as'unimpacted','recently restored'(<4 years),and'mature restored'(>10 years).An additional 28 sites provided information on distances to source populations,while the species'habitat suitability assessed environmental filtering.Biotic(interaction)filtering was evaluated through trait overlap analysis.Results Communities at recently restored sites differed from mature and unimpacted sites,while mature sites resembled unimpacted ones.Taxa at recently restored sites had nearer source populations,while those at mature and unimpacted sites better matched present habitats.Trait overlap did not differ between present and absent taxa.Conclusions Our results indicate that dispersal was essential in early recovery stages,with mass effects from upstream sources supporting taxa found at recently restored sites despite low habitat suitability.Over time,habitat suitability became more influential,shaping mature communities.Competition appeared relatively unimportant,yet competitive exclusion may explain small proportions of absent taxa at mature and recently restored sites.Hence,to effectively support stream recovery,it is essential to consider how different filtering processes operate at various stages of the recovery process.For example,mature communities could further develop if habitat availability increases,while the connectivity to source populations would only play a minor role.展开更多
Diazotrophs make important contributions to nitrogen(N) inputs in agricultural ecosystems. However, strong evidence of the effects of conservation tillage(CT) on the coexistence and assembly of soil diazotrophic commu...Diazotrophs make important contributions to nitrogen(N) inputs in agricultural ecosystems. However, strong evidence of the effects of conservation tillage(CT) on the coexistence and assembly of soil diazotrophic community and related mechanisms is lacking. Here, a long-term experiment was conducted to study the impacts of CT on the coexistence and assembly patterns of soil diazotrophic community in Lishu County, Jilin Province, North China. Compared to traditional tillage(control, CK), CT significantly reduced both the N fixation rate in top 0–10 cm soil and the alpha diversity of diazotrophic community while increasing the density of diazotrophic and overall bacterial communities. Conservation tillage also reduced the competitive relationships within the diazotrophic community and enhanced network stability. Furthermore, diazotroph assembly was dominated by deterministic processes(relative influence =68.63%) under CK and stochastic processes(relative influence = 58.82%) under CT. Soil depth and total N(TN) were identified as crucial predictors shaping the assembly processes of diazotrophic community under different tillage practices. The relative influence of stochastic processes on diazotrophic community under CT varied more significantly with increasing soil depth. Overall, tillage practice and soil depth had significant influences on the coexistence and assembly processes of soil diazotrophic community. Moreover, long-term CT may impact the selection of N fixation agents and the specific taxa associated with N fixers. Our results indicated that in CT systems, relatively sufficient nutrient availability led to a reduction in interspecies competition, an increase in network stability, and a greater influence of stochastic processes on community assembly. These findings may help us better understand biological N fixation in sustainable agricultural systems.展开更多
Understanding microbial community assembly in plants is critical for advancing agricultural sustainability.This study investigated microbial diversity and community assembly mechanisms across six compartments of tomat...Understanding microbial community assembly in plants is critical for advancing agricultural sustainability.This study investigated microbial diversity and community assembly mechanisms across six compartments of tomato plants:bulk soil,rhizosphere,root,stem,flower,and seed.Using 16S rRNA amplicon sequencing,we observed that microbial richness was highest in the bulk soil and rhizosphere,with significant reductions in internal plant tissues.Co‐occurrence network analysis identified distinct microbial hubs in each compartment,such as Bacillus in the root and seed,highlighting critical interactions influencing microbial dynamics.Ecological process modeling revealed that deterministic processes,such as selection,dominated in below‐ground compartments,whereas stochastic processes like drift were more influential in above‐ground tissues,reflecting differences in niche specificity and ecological stability.Dispersal limitation emerged as a key driver in soil‐associated compartments,structuring microbial diversity.These findings advance our understanding of the ecological mechanisms shaping plant microbiomes and suggest targeted microbiome management strategies to enhance crop health,productivity,and resilience.Future research integrating functional genomics,temporal dynamics,and environmental factors is necessary to uncover the broader implications of plant‐associated microbiomes.展开更多
Plant diversity significantly impacts ecosystem processes and functions,yet its influence on the community assembly of leaf fungi remains poorly understood.In this study,we investigated leaf epiphytic and endophytic f...Plant diversity significantly impacts ecosystem processes and functions,yet its influence on the community assembly of leaf fungi remains poorly understood.In this study,we investigated leaf epiphytic and endophytic fungal communities in a Chinese subtropical tree species richness experiment,ranging from 1 to 16 species,using amplicon sequencing to target the internal transcribed spacer 1 region of the rDNA.We found that the community assembly of epiphytic and endophytic fungi was predominantly governed by stochastic processes,with a higher contribution of dispersal limitation on epiphytic than on endophytic fungal communities but a higher contribution of selection on endophytic than on epiphytic fungal communities.The plant-epiphytic fungus interaction network was more complex(e.g.,more highly connected and strongly nested but less specialized and modularized)than the plant-endophytic fungus interaction network.Additionally,tree species richness was positively correlated with the network complexity and diversity of epiphytic(α-,β-andγ-diversity)and endophytic(β-andγ-diversity)fungi,but was not associated with the contribution of the stochastic and deterministic processes on the community assembly of epiphytic and endophytic fungi.This study highlights that tree species diversity enhances the diversity and network complexity,rather than alters the ecological processes in community assembly of leaf-associated fungi.展开更多
Aims To examine if and how species and phylogenetic diversity change in relation to disturbance,we conducted a review of ecological literature by testing the consistency of the relationship between phylogenetic divers...Aims To examine if and how species and phylogenetic diversity change in relation to disturbance,we conducted a review of ecological literature by testing the consistency of the relationship between phylogenetic diversity and disturbance and compared taxonomic groups,type of disturbance and ecosystem/habitat context.We provide a case study of the phylogenetic diversity–disturbance relationship in angiosperm plant communities of a boreal forest region,compared with types of natural and anthropogenic disturbances and plant growth forms.Methods Using a large-scale sampling plot network along a complete(0–100%)anthropogenic disturbance gradient in the boreal biome,we compared the changes of angiosperm plant community structure and composition across plots.We estimated natural disturbance with historical records of major fires.We then calculated phylogenetic diversity indexes and determined species richness in order to compare linear and polynomial trends along disturbance gradients.We also compared the changes of community structure for different types of anthropogenic disturbances and examined how the relationships between species and phylogenetic diversity and disturbance regimes vary among three different life forms(i.e.forbs,graminoids and woody plants).Important Findings Phylogenetic diversity was inconsistently related to disturbance in previous studies,regardless of taxon,disturbance type or ecosystem context.In the understudied boreal ecosystem,angiosperm plant communities varied greatly in species richness and phylogenetic diversity along anthropogenic disturbance gradients and among different disturbance types.In general,a quadratic curve described the relationship between species richness and anthropogenic disturbance,with the highest richness at intermediate anthropogenic disturbance levels.However,phylogenetic diversity was not related to disturbance in any consistent manner and species richness was not correlated with phylogenetic diversity.Phylogenetic relatedness was also inconsistent across plant growth forms and different anthropogenic disturbance types.Unlike the inconsistent patterns observed for anthropogenic disturbance,community assembly among localities varying in time since natural disturbance exhibited a distinct signature of phylogenetic relatedness,although those trends varied among plant growth forms.展开更多
Aims Environmental heterogeneity is a primary mechanism explain-ing species coexistence and extant patterns of diversity.Despite strong theoretical support and ample observational evidence,few experimental studies in ...Aims Environmental heterogeneity is a primary mechanism explain-ing species coexistence and extant patterns of diversity.Despite strong theoretical support and ample observational evidence,few experimental studies in plant communities have been able to demonstrate a causal link between environmental heterogene-ity and plant diversity.This lack of experimental evidence sug-gests that either fine-scale heterogeneity has weak effects on plant diversity or previous experiments have been unable to effectively manipulate heterogeneity.Here,we utilize a unique soil manipu-lation to test whether fine-scale soil heterogeneity will increase plant richness through species sorting among experimental patch types.Methods This experiment was conducted in the tallgrass prairie region of south-central Kansas,USA.We utilized the inherent variation found in the vertical soil profile,which varied in both biotic and abiotic characteristics,and redistributed these strata into either homoge-neous or heterogeneous spatial arrangements in 2.4×2.4 m plots.After the soil manipulation,34 native prairie species were sown into all plots.We conducted annual censuses at peak biomass to quantify species composition and plant density by species within the experimental communities.Important Findings After 2 years,species richness was significantly higher in heteroge-neous relative to homogeneous plots and this pattern was independ-ent of total plant density.In the heterogeneous plots,13 species had higher establishment in a specific patch type representing one of the three soil strata.Conversely,no species had greater estab-lishment in the mixed stratum,which comprised the homogene-ous plots,relative to the heterogeneous strata.These species sorting patterns suggest that fine-scale heterogeneity creates opportunities for plant establishment due to niche differences,which translates into increased plant diversity at the plot scale.Species richness was more strongly related to plant density among patches comprising homogenous plots-where fine-scale heterogeneity was minimized,but weak in heterogeneous plots.This pattern is consistent with the idea that richness-density relationships dominate when neutral pro-cesses are important but are weak when niche processes operate.Unlike many previous attempts,our results provide clear,experi-mental evidence that fine-scale soil heterogeneity increases species richness through species sorting during community assembly.展开更多
Denitrifying bacteria are a crucial component of aquatic ecosystem in nitrogen cycle.However,the denitrifying bacterial community dynamics and structure in epiphytic biofilms remain unexplored.The abundance of denitri...Denitrifying bacteria are a crucial component of aquatic ecosystem in nitrogen cycle.However,the denitrifying bacterial community dynamics and structure in epiphytic biofilms remain unexplored.The abundance of denitrification gene(nir)and structure of nirS-denitrifying bacterial community in the epiphytic biofilms collected in July and November of 2018 from a typical plateau lake(Caohai Wetland,Guizhou,China)were studied by Real-time Quantitative Polymerase Chain Reaction(qPCR)and highthroughput sequencing.Results show that the gene abundance of nirK was higher than that of nirS(P<0.05),and it was significantly different during the growth period(July)than the decline period(November).The denitrifying bacterial species was similar in the two months and shared 76.18%of OTUs.Proteobacteria(56.55%±22.15%)was the dominant phylum in all the samples.Epiphytic biofilms between growth period and decline period displayed significantly different microbial community structures due to differences in species abundance.Water temperature was the crucial factor that affected the denitrifying microbial community structure in our study.Environmental factors explain only partially the dynamic characteristics of denitrifying microbial communities,implying that the stochastic processes affected the construction of denitrifying microbial communities.As the null model analysis results show,dispersal limitation(stochastic)and undominated processes significantly influenced the assembly of denitrifying microbial communities.This study broadened our understanding of the denitrifying bacterial community structure and its function on epiphytic biofilms in freshwater ecosystems with new information provided.展开更多
The rare microbial biosphere provides broad ecological services and resilience to various ecosystems.Nevertheless,the biogeographical patterns and assembly processes of rare bacterioplankton communities in large river...The rare microbial biosphere provides broad ecological services and resilience to various ecosystems.Nevertheless,the biogeographical patterns and assembly processes of rare bacterioplankton communities in large rivers remain uncertain.In this study,we investigated the biogeography and community assembly processes of abundant and rare bacterioplankton taxa in the Yangtze River(China)covering a distance of 4300 km.The results revealed similar spatiotemporal patterns of abundant taxa(AT)and rare taxa(RT)at both taxonomic and phylogenetic levels,and analysis of similarities revealed that RT was significantly influenced by season and landform than AT.Furthermore,RT correlated with more environmental factors than AT,whereas environmental and spatial factors explained a lower proportion of community shifts in RT than in AT.The steeper distance–decay slopes in AT indicated higher spatial turnover rates of abundant subcommunities than rare subcommunities.The null model revealed that both AT and RT were mainly governed by stochastic processes.However,dispersal limitation primarily governed the AT,whereas the undominated process accounted for a higher fraction of stochastic processes in RT.River flow and suspended solids mediated the balance between the stochastic and deterministic processes in RT.The spatiotemporal dynamics and assembly processes of total taxa were more similar as AT than RT.This study provides new insights into both significant spatiotemporal dynamics and inconsistent assembly processes of AT and RT in large rivers.展开更多
Aims Intraspecific trait variation(ITV)has been increasingly recognized to play an important role in understanding the underlying processes influencing community assembly.However,gaps remain in our understanding of ho...Aims Intraspecific trait variation(ITV)has been increasingly recognized to play an important role in understanding the underlying processes influencing community assembly.However,gaps remain in our understanding of how incorporating ITV will influence the relative importance of deterministic(e.g.habitat filtering,limiting similarity)and stochastic processes in driving community assembly at different successional stages.Methods We used data for eight functional traits from 55 woody species in early(24 ha)and late(25 ha)successional temperate forest plot in northeast China.We employed an approximate Bayesian com-putation approach to assess the relative contribution of stochastic processes,habitat filtering and limiting similarity in driving commu-nity structure.We then compared the results with and without intra-specific trait variation to investigate how ITV influences the inferred importance of each process.Important Findings We found that when analyzing interspecific trait variation only(i.e.without ITV),stochastic processes were observed most frequently in driving community composition,followed by habitat filtering and limiting similarity in both forests.However,ITV analyses showed that the relative importance of both deterministic processes(habitat filtering and limiting similarity)increased in early successional for-est,but remained virtually unchanged in late successional forest.Our study reveals the distinctive influence of ITV on the inference of underlying processes in a context of succession and reinforces the need to estimate ITV for making correct inferences about underlying ecological processes.展开更多
Biochar and dung amendments have been extensively employed in soil remediation and fertilization of grasslands,which are the largest terrestrial sinks for methane.However,how these exogenous amendments regulate methan...Biochar and dung amendments have been extensively employed in soil remediation and fertilization of grasslands,which are the largest terrestrial sinks for methane.However,how these exogenous amendments regulate methane metabolisms at the molecular and community levels remains elusive.In this study,we investigated the functional genes and community assemblies of methanogens and methanotrophs using Geochip 5.0 and high-throughput sequencing to reveal the impacts of biochar and dung on soil methanogenesis and methane oxidation.The interac-tions between methane metabolic genes and other biogeochemical genes were also examined.According to Geo-chip microarrays,methanogenic gene mcrA decreased and increased with dung or biochar amendment,respectively;The methanotrophic gene pmoA showed a reverse but not significant tendency.Undominated processes contributed 65.51%to replace homogeneous selections as primary driving forces of methanogen assembly after dung amend-ment;the contribution of dispersal limitation increased to 46.13%in methanotroph assembly after biochar amend-ment.The diversity and association of co-occurrence networks for carbon-nitrogen cycling genes decreased after exogenous amendments.These results indicated that biochar and dung amendments prominently regulated the functional genes and community assembly involved in methane metabolisms.The co-existence patterns of methane metabolic genes and other related geochemical genes were also shaped by these amendments.This study provides the scientific reference for the development of grassland management in the context of global warming.展开更多
基金supported by grants from the National Natural Science Foundation of China for Excellent Young Scientists Fund Program(No.42222105)the National Natural Science Foundation of China General Program(No.42171144)+1 种基金the Assessment of Ecosystem Carbon Stock and Turnover Patterns in Qinghai Province(No.2021-SFA7-1-1)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2021QZKK0100)。
文摘Bacterial communities play a crucial role in permafrost biogeochemical cycling and ecosystem function maintenance.Bacterial interaction is one of the main factors in shaping soil bacterial communities.However,how would bacterial interaction influence the bacterial communities in permafrost of the Qinghai-Tibet Plateau(QTP)remains largely unknown.Here we collected paired soil samples from both the active and permafrost layers of two typical QTP permafrost regions in October 2020 for Tuotuohe River(TTH)and May 2022 for Aerjin(ARJ),and investigated the bacterial communities and the role of interactions in structuring the bacterial community and its assembly process through amplicon sequencing of the 16S rRNA gene.Our study revealed distinct bacterial communities,with significant differences in the relative abundances of Proteobacteria(P<0.05),Acidobacteriota(P<0.001),Bacteroidota(P<0.05),and Planctomycetota(P<0.001)between the active layer and the permafrost layer.More importantly,we found that interspecies interactions,including both positive and negative associations,were strongly correlated with bacterial alpha-diversity and played a significant role in community variation and assembly process.Our findings also showed that the community assembly in both the active and permafrost layers was primarily driven by homogeneous selection of deterministic processes,with interspecies interactions accounting for more than 58%and 63%of all assembly mechanisms,respectively.This is the first study to quantify the contribution of bacterial interactions in shaping the bacterial community and its assembly process in permafrost of QTP,highlighting the importance of considering interspecies interactions in future modeling efforts.Our work also emphasizes the necessity of including interspecies interactions in microbial process projections to reduce uncertainty.
基金supported by the Educational Commission of Anhui Province of China(No.KJ2021A0168)the Research Fund of Anhui Agricultural University(No.rc422112).
文摘The environmental impacts of acid mine drainage(AMD)from open-pit mining are profoundly detrimental,yet knowledge about its effects on paddy soil microbial communities,especially at greater depths,remains limited.In this investigation,we compared soils affected by AMD versus unaffected soil depth profiles in terms of bacterial diversity and community assembly.The profiles in AMD-polluted soils exhibited tight geochemical gradients,characterized by increased acidity,SO_(4)^(2-),NO_(3)^(-),and heavy metal content compared to unpolluted soils.Notably,AMD significantly diminished soil bacterial biodiversity.A depthwise analysis showed distinct microbial stratification,with certain bacteria like Candidatus_Solibacter and Candidatus_Koribacter predominated in polluted soils,while others like Haliangium and Nitrospira were more prevalent in control soils.Interestingly,despite variable soil conditions,predictedmetabolic pathways,particularly those involving carbon,nitrogen,and sulfur,showed relative stability.AMD pollution induced the upregulation of methylcoenzyme M reductase and sulfate reductase genes.Bacterial communities were more responsive to pH and nutrient content rather than heavy metals,with pH and SO_(4)^(2-)being the primary drivers of microbial diversity and distribution.Additionally,pHwas identified as the most significant influence on the predicted methane,sulfur,and nitrogen metabolism.Furthermore,deterministic processes played a more significant role in community assembly of polluted soils,while heterogeneous selection gained importance with increasing depth in control soils.Additionally,microbial co-occurrences,particularly positive interactions,were more prevalent in the polluted soils with reduced network modularity and keystone taxa.These findings offer insights into sustaining microbial diversity in extreme environments.
基金supported by the Foundation of the University of Quebec in Abitibi-Témiscamingue(FUQAT)Quebec Research Fund(FRQ)(2021-SE7-282961)。
文摘Understanding plant community assembly is crucial for effective ecosystem conservation and restoration.The ecological filter framework describes community assembly as a process shaped by dispersal,environmental,and biotic filters.Additionally,functional traits and phylogenetic relationships are increasingly recognized as important factors influencing species coexistence and community structure.However,both the ecological filter framework and the roles of functional traits and phylogeny in community assembly remain underexplored in the Algerian steppes—particularly in the El Bayadh region,where ongoing vegetation degradation threatens ecosystem stability.This study applied Hierarchical Modeling of Species Communities(HMSC)as an integrative approach to assess how ecological filters influence plant community assembly in the El Bayadh steppe and to evaluate the roles of functional traits and phylogenetic relationships in this process.Environmental data—including soil properties,topography,precipitation,and land use types(grazing and exclosure)—were collected across 50 plots in April and October,2023,along with functional traits from 24 species.These traits include root length,leaf area,specific leaf area,clonality,life history,and seed mass.HMSC results revealed that soil properties and precipitation were the primary drivers of community structure,while sand height and elevation had a moderate influence.In contrast,competition and grazing played relatively minor roles.Species responses to environmental covariates were heterogeneous:soil fertility and texture had mixed effects,benefiting some species while limiting others;sand encroachment and precipitation variability generally had negative impacts,whereas grazing exclusion favored many species.A weak phylogenetic signal was recorded,indicating that community assembly was driven more by environmental filtering than by shared evolutionary history.Functional trait responses to environmental variation reflected plant strategies that balanced resource acquisition and conservation.Specifically,seed mass,leaf area,and root length increased under higher soil moisture and nutrient availability but declined in response to salinity,precipitation variability,and sand height.Clonality and perennial life history traits enhanced the survival of plant species under harsh conditions.Overall,this study provides a holistic understanding of community assembly processes in the El Bayadh steppe and offers valuable insights for ecosystem management and restoration in arid and degraded ecosystem environments.
基金funded by the National Natural Science Foundation of China(Grant No.42271116)。
文摘As one of the important wintering areas along the East Asian-Australasian Flyway,wetlands in the Yangtze River floodplain face threats from land-use changes,yet its effects on wintering waterbirds at the landscape level remain understudied,impeding conservation practice.Here,using survey data collected across 14 inland lakes in Jiangsu Province in 2022,we calculated wintering waterbirds diversity(taxonomic,functional,phylogenetic)and assembly patterns(MPD/MNTD of functional and phylogenetic).Then,we interpreted satellite imagery of lake areas and buffer zones(5 km),and partitioned them into three land-use and landscape index categories(anthropogenic,ecological,and lake landscape).Finally,we employed multiple linear regression and hierarchical partitioning to explain the influence of landscape scales on wintering waterbird communities.Our results showed that the diversity and assembly of regional wintering waterbird communities tended to be consistent across taxonomic,functional,and phylogenetic dimensions.The standardized diversity indices indicated that functional assembly of communities tends to be clustered at both local and regional scale.In contrast,the phylogenetic structure showed a predominantly overdispersed pattern in most lakes at the local scale,while neutral processes dominated at the regional scale.Modeling showed that selected variables explained waterbird diversity and assembly well.Lake fragmentation increased species evenness but reduced other diversity indices,while landscape evenness was negatively associated with functional and phylogenetic assembly.Among anthropogenic factors,aquaculture ponds and impervious surfaces reduced all diversity dimensions,whereas cropland connectivity enhanced phylogenetic diversity.These factors had consistent effects on community assembly.For ecological variables,grassland area enhanced functional and phylogenetic diversity but led to more clustered functional assembly.Overall,maintaining the integrity and connectivity of lakes and their surrounding landscapes is essential for sustaining waterbird diversity and guiding wetland restoration.
基金supported by the National Natural Science Foundation of China (42071073,31971487)Youth Innovation Promotion Association of the Chinese Academy of Sciences (2021366)+2 种基金Guangxi Key Research and Development Program (AB17129009)the Hechi Distinguished Expert Program to Fuping Zengthe Guangxi Bagui Scholarship Program to Dejun Li。
文摘Spatial and environmental processes are two ecological processes that have attracted considerable attention in plant community assembly,depending on sampling scale and life history.However,the processes that determine community assembly have not been studied in the karst region of southwest China.In this study,a 25-ha(500 m×500 m)monitoring plot within the subtropical climax forest in the karst region was established and canonical correspondence analysis was used to reveal the effects of topography and soil on the spatial patterns of tree community assembly.Our study suggests that spatial processes dominate species composition and the combined effects of spatial and environmental processes play an important role.Overall interpretation rate increases with enlarging the sampling scale.However,the pattern of variation partitioning was similar in different life stages.Environmental variables significantly affected species composition at different sampling sizes and life histories and had a higher interpretation rate of species composition on larger s ampling sizes.Topographic wetness index was the most important variable to explain species composition of the environmental variables.These results suggest that it is necessary to consider the relative importance of environmental and spatial factors on community assembly to better understand,conserve,and manage subtropical karst forests.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDB31000000the National Natural Science Foundation of China(No.31370267).
文摘The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.
基金This work was supported by the National Natural Science Foundation of China(No.51578537)Chinese Academy of Sciences(No.QYZDY-SSW-DQC004)。
文摘Lake mixing influences aquatic chemical properties and microbial community composition,and thus,we hypothesized that it would alter microbial community assembly and interac-tion.To clarify this issue,we explored the community assembly processes and cooccurrence networks in four seasons at two depths(epilimnion and hypolimnion)in a mesotrophic and stratified lake(Chenghai Lake),which formed stratification in the summer and turnover in the winter.During the stratification period,the epilimnion and hypolimnion went through contrary assembly processes but converged to similar assembly patterns in the mixing pe-riod.In a highly homogeneous selection environment,species with low niche breadth were filtered,resulting in decreased species richness.Water mixing in the winter homogenized the environment,resulting in a simpler microbial cooccurrence network.Interestingly,we observed a high abundance of the cyanobacterial genus Planktothrix in the winter,proba-bly due to nutrient redistribution and Planktothrix adaptivity to the winter environment in which mixing played important roles.Our study provides deeper fundamental insights into how environmental factors influence microbial community structure through community assembly processes.
基金supported by the National Natural Science Foundation of China (31800353)the Yunnan Fundamental Research Projects (202101AV070005)+4 种基金Yunnan High Level Talents Special Support Plan (YNWR-QNBJ-2018-309)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y202080)the West Light Foundation of the Chinese Academy of Sciencessupported by the National Science Foundation United States (NSF DEB-2029997)
文摘Predicting species abundance is one of the most fundamental pursuits of ecology.Combining the information encoded in functional traits and metacommunities provides a new perspective to predict the abundance of species in communities.We applied a community assembly via trait selection model to predict quadrat-scale species abundances using functional trait variation on ontogenetic stages and metacommunity information for over 490 plant species in a subtropical forest and a lowland tropical forest in Yunnan,China.The relative importance of trait-based selection,mass effects,and stochasticity in shaping local species abundances is evaluated using different null models.We found both mass effects and trait selection contribute to local abundance patterns.Trait selection was detectable at all studied spatial scales(0.04e1 ha),with its strength stronger at larger scales and in the subtropical forest.In contrast,the importance of stochasticity decreased with spatial scale.A significant mass effect of the metacommunity was observed at small spatial scales.Our results indicate that tree community assembly is primarily driven by ontogenetic traits and metacommunity effects.Our findings also demonstrate that including ontogenetic trait variation into predictive frameworks allows ecologists to infer ecological mechanisms operating in community assembly at the individual level.
基金supported by Shanghai Municipal Natural Science Foundation,China(No.21ZR1446800)the National Natural Science Foundation of China(No.41877425)the Fundamental Research Funds for the Central Universities(No.226-2024-00052)。
文摘Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community assembly in virgin and aging MP plastispheres across different habitats is poorly understood.This study aims to assess the variations in bacterial community assembly across different niches and habitats with an in situ ex-periment,in which constructed forest wetland(FW),natural lake wetland(LW),and lotus pond wetland(LP)were habitats,and plastispheres of virgin and aging low-density polyethylene(LDPE)MPs,as well as surround-ing wetland soils were niches.Significant niche-related differences in bacterial communities were observed,with lower diversity and enrichment of potential plastic-degrading bacteria in the plastisphere than in the soil bacterial communities.Furthermore,habitat-related differences exerted a more pronounced influence on the beta-diversity patterns of the bacterial communities.The linear regression analyses indicated that the local species pool con-tributed more to bacterial community assembly in the LW wetland,whereas the relative abundance of species was the primary factor in the LP wetland.The null model analysis indicated that plastisphere bacterial communi-ties were predominantly driven by the stochastic process,with a more deterministic assembly observed in the LP wetland and soil bacterial communities.Additionally,the primary ecological process shaping plastisphere com-munities shifted from drift in the virgin LDPE to homogenising dispersal in the aging LDPE.This study provides new insights into the fate and ecological impacts of MPs in wetlands,thereby facilitating the effective regulations of plastic pollution.
基金supported by the National Natural Science Foundation of China(32130013)the National Key Research and Development Program of China(2022YFC2601601)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK05010112,2019QZKK0304-02)Dynamic Monitoring of Distribution,Quantity and Activity of Typical Large and Medium-sized Mammals in the Yarlung Tsangpo River Basin(54000022T000000071200)the Institute of Zoology,Chinese Academy of Sciences(2023IOZ0104)
文摘Background Identifying the processes that govern community assembly along elevational gradients has been a central theme in ecology,especially in montane ecosystems where abundant species and strong turnover are present.However,our understanding of how the relative importance of deterministic and stochastic processes varies along elevational gradients remains limited.Here,we compiled a rigorously curated dataset of elevational distributions of 734 breeding bird species across the Hengduan Mountains in China to assess the dominant underlying mechanisms of bird community assembly at both intra-community and inter-community scales across four elevation zones:low,middle,subalpine,and alpine.Results At the intra-community scale,homogeneous dispersal played a pivotal role in driving community assembly of breeding birds across the Hengduan Mountains.Deterministic processes became more influential with increasing elevation,whereas stochastic processes prevailed in low,middle,and subalpine zones.At inter-community scale,assemblages from different elevation zones were more differentiated by dispersal limitation.Non-Passeriformes experienced more obvious influence of homogeneous dispersal but were less subject to dispersal limitation compared to Passeriformes.Conclusions Our findings highlight the role of stochastic processes in shaping biotic communities in montane ecosystems,but this effect is scale-dependent.The transition from stochastic to deterministic processes along elevational gradients suggests that environmental factors become more influential at higher elevations.Species dispersal ability may affect the relative importance of these two processes shaping community assembly.
基金the CRC RESIST,which was funded by the German Research Foundation(Deutsche Forschungsgemeinschaft,DFG)–CRC 1439–project number:426547801
文摘Background Understanding the temporal development of community assembly processes is essential for assessing the recovery of degraded ecosystems after restoration.Community development in restored streams is often slow or absent,due to inadequate restoration,catchment-scale pressures,and/or colonisation barriers.Recovery processes involve three key filters:dispersal,environmental conditions and biotic interactions.Dispersal is critical for initial colonisation,while environmental conditions influence successful population establishment.Lastly,as available niches fill,biotic interactions,such as competition,gain importance.Despite the presence of many theories on how these three filters interact during community assembly,they have rarely been investigated simultaneously.Our detailed species-and site-specific approach allowed us to analyse the three filters in a hierarchical analysis.We assessed the effect of the three filters,by examining benthic invertebrate communities at 20 sites in the Boye catchment(Western Germany).The Boye and most of its tributaries were used as open sewers for a century,i.e.they were concrete channels transporting untreated sewage before gradual restoration was started in the 1990s.The bank reinforcements and concrete beds were removed,while riparian vegetation was left to natural succession.Accordingly,the sites were grouped as'unimpacted','recently restored'(<4 years),and'mature restored'(>10 years).An additional 28 sites provided information on distances to source populations,while the species'habitat suitability assessed environmental filtering.Biotic(interaction)filtering was evaluated through trait overlap analysis.Results Communities at recently restored sites differed from mature and unimpacted sites,while mature sites resembled unimpacted ones.Taxa at recently restored sites had nearer source populations,while those at mature and unimpacted sites better matched present habitats.Trait overlap did not differ between present and absent taxa.Conclusions Our results indicate that dispersal was essential in early recovery stages,with mass effects from upstream sources supporting taxa found at recently restored sites despite low habitat suitability.Over time,habitat suitability became more influential,shaping mature communities.Competition appeared relatively unimportant,yet competitive exclusion may explain small proportions of absent taxa at mature and recently restored sites.Hence,to effectively support stream recovery,it is essential to consider how different filtering processes operate at various stages of the recovery process.For example,mature communities could further develop if habitat availability increases,while the connectivity to source populations would only play a minor role.
基金funded by the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA28020202)the National Natural Science Foundation of China (No. 42277336)+3 种基金the Natural Science Foundation of Jiangsu Province, China (No. BK20221561)the China Agriculture Research System (Nos. CARS-03 and CARS52)the National Key Research and Development Program of China (No. 2022YFD1500401)the Jiangsu Agricultural Science and Technology Innovation Fund of China (No. CX(24)1003)。
文摘Diazotrophs make important contributions to nitrogen(N) inputs in agricultural ecosystems. However, strong evidence of the effects of conservation tillage(CT) on the coexistence and assembly of soil diazotrophic community and related mechanisms is lacking. Here, a long-term experiment was conducted to study the impacts of CT on the coexistence and assembly patterns of soil diazotrophic community in Lishu County, Jilin Province, North China. Compared to traditional tillage(control, CK), CT significantly reduced both the N fixation rate in top 0–10 cm soil and the alpha diversity of diazotrophic community while increasing the density of diazotrophic and overall bacterial communities. Conservation tillage also reduced the competitive relationships within the diazotrophic community and enhanced network stability. Furthermore, diazotroph assembly was dominated by deterministic processes(relative influence =68.63%) under CK and stochastic processes(relative influence = 58.82%) under CT. Soil depth and total N(TN) were identified as crucial predictors shaping the assembly processes of diazotrophic community under different tillage practices. The relative influence of stochastic processes on diazotrophic community under CT varied more significantly with increasing soil depth. Overall, tillage practice and soil depth had significant influences on the coexistence and assembly processes of soil diazotrophic community. Moreover, long-term CT may impact the selection of N fixation agents and the specific taxa associated with N fixers. Our results indicated that in CT systems, relatively sufficient nutrient availability led to a reduction in interspecies competition, an increase in network stability, and a greater influence of stochastic processes on community assembly. These findings may help us better understand biological N fixation in sustainable agricultural systems.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(RS‐2023‐00251252 and 2020R1A6A1A03047729)Rural Development Administration(RS‐2025‐02613089)Biomaterials Specialized Graduate Program through the Korea Environmental Industry&Technology Institute(KEITI)funded by the Ministry of Environment(MOE).
文摘Understanding microbial community assembly in plants is critical for advancing agricultural sustainability.This study investigated microbial diversity and community assembly mechanisms across six compartments of tomato plants:bulk soil,rhizosphere,root,stem,flower,and seed.Using 16S rRNA amplicon sequencing,we observed that microbial richness was highest in the bulk soil and rhizosphere,with significant reductions in internal plant tissues.Co‐occurrence network analysis identified distinct microbial hubs in each compartment,such as Bacillus in the root and seed,highlighting critical interactions influencing microbial dynamics.Ecological process modeling revealed that deterministic processes,such as selection,dominated in below‐ground compartments,whereas stochastic processes like drift were more influential in above‐ground tissues,reflecting differences in niche specificity and ecological stability.Dispersal limitation emerged as a key driver in soil‐associated compartments,structuring microbial diversity.These findings advance our understanding of the ecological mechanisms shaping plant microbiomes and suggest targeted microbiome management strategies to enhance crop health,productivity,and resilience.Future research integrating functional genomics,temporal dynamics,and environmental factors is necessary to uncover the broader implications of plant‐associated microbiomes.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31030000)the National Natural Science Foundation of China (31971496,32170120)+2 种基金the support of Zhejiang Qianjiangyuan Forest Biodiversity National Observation and Research Stationthe International Research Training Group Tree Dìjointly funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, 319936945/GRK2324)the University of Chinese Academy of Science(UCAS).
文摘Plant diversity significantly impacts ecosystem processes and functions,yet its influence on the community assembly of leaf fungi remains poorly understood.In this study,we investigated leaf epiphytic and endophytic fungal communities in a Chinese subtropical tree species richness experiment,ranging from 1 to 16 species,using amplicon sequencing to target the internal transcribed spacer 1 region of the rDNA.We found that the community assembly of epiphytic and endophytic fungi was predominantly governed by stochastic processes,with a higher contribution of dispersal limitation on epiphytic than on endophytic fungal communities but a higher contribution of selection on endophytic than on epiphytic fungal communities.The plant-epiphytic fungus interaction network was more complex(e.g.,more highly connected and strongly nested but less specialized and modularized)than the plant-endophytic fungus interaction network.Additionally,tree species richness was positively correlated with the network complexity and diversity of epiphytic(α-,β-andγ-diversity)and endophytic(β-andγ-diversity)fungi,but was not associated with the contribution of the stochastic and deterministic processes on the community assembly of epiphytic and endophytic fungi.This study highlights that tree species diversity enhances the diversity and network complexity,rather than alters the ecological processes in community assembly of leaf-associated fungi.
基金Alberta Biodiversity Monitoring Institute(to J.Z.and F.H.)University of Alberta(Desmond I Crossley Memorial and Herbert and Jeannette Hall Graduate Scholarships to J.Z.)+1 种基金Natural Sciences and Engineering Research Council of Canada(to S.J.M.and F.H.)the Alberta Ingenuity Fund(to S.J.M.).
文摘Aims To examine if and how species and phylogenetic diversity change in relation to disturbance,we conducted a review of ecological literature by testing the consistency of the relationship between phylogenetic diversity and disturbance and compared taxonomic groups,type of disturbance and ecosystem/habitat context.We provide a case study of the phylogenetic diversity–disturbance relationship in angiosperm plant communities of a boreal forest region,compared with types of natural and anthropogenic disturbances and plant growth forms.Methods Using a large-scale sampling plot network along a complete(0–100%)anthropogenic disturbance gradient in the boreal biome,we compared the changes of angiosperm plant community structure and composition across plots.We estimated natural disturbance with historical records of major fires.We then calculated phylogenetic diversity indexes and determined species richness in order to compare linear and polynomial trends along disturbance gradients.We also compared the changes of community structure for different types of anthropogenic disturbances and examined how the relationships between species and phylogenetic diversity and disturbance regimes vary among three different life forms(i.e.forbs,graminoids and woody plants).Important Findings Phylogenetic diversity was inconsistently related to disturbance in previous studies,regardless of taxon,disturbance type or ecosystem context.In the understudied boreal ecosystem,angiosperm plant communities varied greatly in species richness and phylogenetic diversity along anthropogenic disturbance gradients and among different disturbance types.In general,a quadratic curve described the relationship between species richness and anthropogenic disturbance,with the highest richness at intermediate anthropogenic disturbance levels.However,phylogenetic diversity was not related to disturbance in any consistent manner and species richness was not correlated with phylogenetic diversity.Phylogenetic relatedness was also inconsistent across plant growth forms and different anthropogenic disturbance types.Unlike the inconsistent patterns observed for anthropogenic disturbance,community assembly among localities varying in time since natural disturbance exhibited a distinct signature of phylogenetic relatedness,although those trends varied among plant growth forms.
文摘Aims Environmental heterogeneity is a primary mechanism explain-ing species coexistence and extant patterns of diversity.Despite strong theoretical support and ample observational evidence,few experimental studies in plant communities have been able to demonstrate a causal link between environmental heterogene-ity and plant diversity.This lack of experimental evidence sug-gests that either fine-scale heterogeneity has weak effects on plant diversity or previous experiments have been unable to effectively manipulate heterogeneity.Here,we utilize a unique soil manipu-lation to test whether fine-scale soil heterogeneity will increase plant richness through species sorting among experimental patch types.Methods This experiment was conducted in the tallgrass prairie region of south-central Kansas,USA.We utilized the inherent variation found in the vertical soil profile,which varied in both biotic and abiotic characteristics,and redistributed these strata into either homoge-neous or heterogeneous spatial arrangements in 2.4×2.4 m plots.After the soil manipulation,34 native prairie species were sown into all plots.We conducted annual censuses at peak biomass to quantify species composition and plant density by species within the experimental communities.Important Findings After 2 years,species richness was significantly higher in heteroge-neous relative to homogeneous plots and this pattern was independ-ent of total plant density.In the heterogeneous plots,13 species had higher establishment in a specific patch type representing one of the three soil strata.Conversely,no species had greater estab-lishment in the mixed stratum,which comprised the homogene-ous plots,relative to the heterogeneous strata.These species sorting patterns suggest that fine-scale heterogeneity creates opportunities for plant establishment due to niche differences,which translates into increased plant diversity at the plot scale.Species richness was more strongly related to plant density among patches comprising homogenous plots-where fine-scale heterogeneity was minimized,but weak in heterogeneous plots.This pattern is consistent with the idea that richness-density relationships dominate when neutral pro-cesses are important but are weak when niche processes operate.Unlike many previous attempts,our results provide clear,experi-mental evidence that fine-scale soil heterogeneity increases species richness through species sorting during community assembly.
基金*Supported by the National Natural Science Foundation of China(No.41867056)the Joint Fund of the National Natural Science Foundation of China and the Karst Science Research Center of Guizhou Province(No.U1812401)+1 种基金the Guizhou Province Graduate Education Innovation Project(No.YJSCXJH(2019)048)the Science and Technology Support Project of Guizhou Province(No.2021470)。
文摘Denitrifying bacteria are a crucial component of aquatic ecosystem in nitrogen cycle.However,the denitrifying bacterial community dynamics and structure in epiphytic biofilms remain unexplored.The abundance of denitrification gene(nir)and structure of nirS-denitrifying bacterial community in the epiphytic biofilms collected in July and November of 2018 from a typical plateau lake(Caohai Wetland,Guizhou,China)were studied by Real-time Quantitative Polymerase Chain Reaction(qPCR)and highthroughput sequencing.Results show that the gene abundance of nirK was higher than that of nirS(P<0.05),and it was significantly different during the growth period(July)than the decline period(November).The denitrifying bacterial species was similar in the two months and shared 76.18%of OTUs.Proteobacteria(56.55%±22.15%)was the dominant phylum in all the samples.Epiphytic biofilms between growth period and decline period displayed significantly different microbial community structures due to differences in species abundance.Water temperature was the crucial factor that affected the denitrifying microbial community structure in our study.Environmental factors explain only partially the dynamic characteristics of denitrifying microbial communities,implying that the stochastic processes affected the construction of denitrifying microbial communities.As the null model analysis results show,dispersal limitation(stochastic)and undominated processes significantly influenced the assembly of denitrifying microbial communities.This study broadened our understanding of the denitrifying bacterial community structure and its function on epiphytic biofilms in freshwater ecosystems with new information provided.
基金supported by National Natural Science Foundation of China(Grant No.41907203)China Postdoctoral Science Foundation(202IT 140010).
文摘The rare microbial biosphere provides broad ecological services and resilience to various ecosystems.Nevertheless,the biogeographical patterns and assembly processes of rare bacterioplankton communities in large rivers remain uncertain.In this study,we investigated the biogeography and community assembly processes of abundant and rare bacterioplankton taxa in the Yangtze River(China)covering a distance of 4300 km.The results revealed similar spatiotemporal patterns of abundant taxa(AT)and rare taxa(RT)at both taxonomic and phylogenetic levels,and analysis of similarities revealed that RT was significantly influenced by season and landform than AT.Furthermore,RT correlated with more environmental factors than AT,whereas environmental and spatial factors explained a lower proportion of community shifts in RT than in AT.The steeper distance–decay slopes in AT indicated higher spatial turnover rates of abundant subcommunities than rare subcommunities.The null model revealed that both AT and RT were mainly governed by stochastic processes.However,dispersal limitation primarily governed the AT,whereas the undominated process accounted for a higher fraction of stochastic processes in RT.River flow and suspended solids mediated the balance between the stochastic and deterministic processes in RT.The spatiotemporal dynamics and assembly processes of total taxa were more similar as AT than RT.This study provides new insights into both significant spatiotemporal dynamics and inconsistent assembly processes of AT and RT in large rivers.
基金This work was supported by the National Natural Science Foundation of China[31722010,31770666,31730015,and 31670632]the Strategic Priority Research Program of the Chinese Academy of Sciences[XDB31030000]+2 种基金M.W.C wishes to acknowledge support from the Natural Sciences and Engineering Research Council of Canada[#386151]an Early Researcher Award from the Ontario Ministry of Research and Innovation[ER13-09-121]the TD Chair of Urban Forest Conservation and Biology endowment.
文摘Aims Intraspecific trait variation(ITV)has been increasingly recognized to play an important role in understanding the underlying processes influencing community assembly.However,gaps remain in our understanding of how incorporating ITV will influence the relative importance of deterministic(e.g.habitat filtering,limiting similarity)and stochastic processes in driving community assembly at different successional stages.Methods We used data for eight functional traits from 55 woody species in early(24 ha)and late(25 ha)successional temperate forest plot in northeast China.We employed an approximate Bayesian com-putation approach to assess the relative contribution of stochastic processes,habitat filtering and limiting similarity in driving commu-nity structure.We then compared the results with and without intra-specific trait variation to investigate how ITV influences the inferred importance of each process.Important Findings We found that when analyzing interspecific trait variation only(i.e.without ITV),stochastic processes were observed most frequently in driving community composition,followed by habitat filtering and limiting similarity in both forests.However,ITV analyses showed that the relative importance of both deterministic processes(habitat filtering and limiting similarity)increased in early successional for-est,but remained virtually unchanged in late successional forest.Our study reveals the distinctive influence of ITV on the inference of underlying processes in a context of succession and reinforces the need to estimate ITV for making correct inferences about underlying ecological processes.
基金the National Key Research and Development Program of China(No.2018YFD0800403).
文摘Biochar and dung amendments have been extensively employed in soil remediation and fertilization of grasslands,which are the largest terrestrial sinks for methane.However,how these exogenous amendments regulate methane metabolisms at the molecular and community levels remains elusive.In this study,we investigated the functional genes and community assemblies of methanogens and methanotrophs using Geochip 5.0 and high-throughput sequencing to reveal the impacts of biochar and dung on soil methanogenesis and methane oxidation.The interac-tions between methane metabolic genes and other biogeochemical genes were also examined.According to Geo-chip microarrays,methanogenic gene mcrA decreased and increased with dung or biochar amendment,respectively;The methanotrophic gene pmoA showed a reverse but not significant tendency.Undominated processes contributed 65.51%to replace homogeneous selections as primary driving forces of methanogen assembly after dung amend-ment;the contribution of dispersal limitation increased to 46.13%in methanotroph assembly after biochar amend-ment.The diversity and association of co-occurrence networks for carbon-nitrogen cycling genes decreased after exogenous amendments.These results indicated that biochar and dung amendments prominently regulated the functional genes and community assembly involved in methane metabolisms.The co-existence patterns of methane metabolic genes and other related geochemical genes were also shaped by these amendments.This study provides the scientific reference for the development of grassland management in the context of global warming.
