As a significant city in the Yangtze River Delta regions,Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion.However,there has been limite...As a significant city in the Yangtze River Delta regions,Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion.However,there has been limited research in recent years on the spatial-temporal distribution and emission of its atmospheric pollutants.To address this,this study conducted mobile observations of urban roads using the Mobile-DOAS instrument from June 2021 to May 2022.The monitoring results exhibit a favourable consistent with TROPOMI satellite data and ground monitoring station data.Temporally,there were pronounced seasonal variations in air pollutants.Spatially,high concentration of HCHO and NO_(2)were closely associated with traffic congestion on roadways,while heightened SO_(2)levels were attributed to winter heating and industrial emissions.The study also revealed that with the implementation of road policies,the average vehicle speed increased by 95.4%,while the NO concentration decreased by 54.4%.In the estimation of urban NO_(x)emission flux,it was observed that in temporal terms,compared with inventory data,the emissions calculated viamobile measurements exhibitedmore distinct seasonal patterns,with the highest emission rate of 349 g/sec in winter and the lowest of 142 g/sec in summer.In spatial terms,the significant difference in emissions between the inner and outer ring roads also suggests the presence of the city’s primary NO_(x)emission sources in the area between these two rings.This study offers data support for formulating the next phase of air pollution control measures in urban areas.展开更多
[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in t...[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.展开更多
Predicting whether alien species will invade a native community is a key challenge in invasion ecology.One factor that may help predict invasion success is phylogenetic relatedness.Darwin proposed that closely related...Predicting whether alien species will invade a native community is a key challenge in invasion ecology.One factor that may help predict invasion success is phylogenetic relatedness.Darwin proposed that closely related species tend to share similar niches,although this relationship may be influenced by various ecological and evolutionary factors.To test this,we classified alien Asteraceae species in China into three categories based on their invasion status and the extent of ecological damage:introduced,naturalized,and invasive.We then compared the genetic relationships and niche overlap between alien and native Asteraceae species.We found that invasive Asteraceae species are more closely related to native Asteraceae species than are introduced and naturalized species.However,alien Asteraceae species(including introduced,naturalized,and invasive species)exhibited relatively low niche overlap with native Asteraceae species.These findings suggest that the main premise underlying Darwin’s naturalization conundrum,namely,the universality of phylogenetic niche conservatism,may not hold true.Instead,our findings indicate that alien species are more likely to invade successfully when they are more closely related to native plants,exhibit less niche overlap,and maintain conservative niches during the invasion process.These findings provide new insights into the mechanisms of alien plant invasions,highlight the relationship between alien species invasions and native community vulnerability,and offer important insights into the development of effective biological invasion management strategies.展开更多
In the current situation of decelerating economic expansion,examining the digital economy(DE)as a novel economic model is beneficial for the local economy’s sustainable and high-quality development(HQD).We analyzed p...In the current situation of decelerating economic expansion,examining the digital economy(DE)as a novel economic model is beneficial for the local economy’s sustainable and high-quality development(HQD).We analyzed panel data from the Yellow River(YR)region from 2013 to 2021 and discovered notable spatial variances in the composite index and coupling coordination of the two systems.Specifically,the downstream region exhibited the highest coupling coordination,while the upstream region had the lowest.We identified that favorable factors such as economic development,innovation,industrial upgrading,and government intervention can bolster the coupling.Our findings provide a valuable framework for promoting DE and HQD in the YR region.展开更多
Accurate capture and presentation of the interactive feedback relationships among various objectives in multi-objective reservoir operation is essential for maximizing operational benefits.In this study,the niche theo...Accurate capture and presentation of the interactive feedback relationships among various objectives in multi-objective reservoir operation is essential for maximizing operational benefits.In this study,the niche theory of ecology was innovatively applied to the field of reservoir operation,and a novel state-relationship(S-R)measurement analysis method was developed for multi-objective reservoir operation.This method enables the study of interaction among multiple objectives.This method was used to investigate the relationship among the objectives of power generation,water supply,and ecological protection for cascade reservoir operation in the Wujiang River Basin in China.The results indicated that the ecological protection objective was the most competitive in acquiring and capturing resources like flow and water level,while the water supply objective was the weakest.Power generation competed most strongly with ecological protection and relatively weakly with water supply.These findings facilitate decision-making throughout the reservoir operation process in the region.The S-R method based on the niche theory is convenient,efficient,and intuitive,allowing for the quantification of feedback relationships among objectives without requiring the solution of the Pareto frontier of a multi-objective problem in advance.This method provides a novel and feasible idea for studying multi-objective interactions.展开更多
The transformation of natural habitats into human-modified landscapes has far-reaching consequences for species distribution and abundance.As species adapt to these changing environments,shifts in distribution pattern...The transformation of natural habitats into human-modified landscapes has far-reaching consequences for species distribution and abundance.As species adapt to these changing environments,shifts in distribution patterns,niche dynamics,and interspecies interactions may occur,impacting biodiversity at multiple levels and potentially leading to ecosystem imbalances.This study aims to assess the impact of variations in vegetation composition and human disturbance on the distribution of sympatric breeding birds and to determine the extent of niche overlap or differentiation among these species.We conducted field surveys and collected data on bird distribution,vegetation composition,and level of human disturbance in eastern Inner Mongolian grasslands.We focused on the six most frequently co-occurring breeding birds,representing a mix of sparrows,larks,and corvids.Generalized Additive Models revealed varying responses of species occurrence along habitat gradients.Species like the Eurasian Skylark(Alauda arvensis),Mongolian Lark(Melanocorypha mongolica),and Asian Shorttoed Lark(Calandrella cheleensis),increased in larger and more connected habitats,while others,like the Tree Sparrow(Passer montanus),Eurasian Magpie(Pica pica),and Barn Swallow(Hirundo rustica),adapted to more fragmented habitats.Niche analysis indicated habitat generalists tended to occupy larger niches than grassland specialists.Substantial niche overlap was also found among the six co-occurring bird species.Conservation efforts should consider the specific needs of specialist species and strive to maintain or restore critical grassland habitats.Additionally,promoting sustainable agricultural practices that balance the needs of birds and human activities can contribute to the coexistence of generalist and specialist bird species in modified landscapes.展开更多
Urbanization and industrialization have heightened the risk of groundwater contamination in karst regions,threatening the safety of petrifying spring water.Petrifying spring-moss systems serve as critical interfaces f...Urbanization and industrialization have heightened the risk of groundwater contamination in karst regions,threatening the safety of petrifying spring water.Petrifying spring-moss systems serve as critical interfaces for groundwater-surface water interaction,retaining potentially toxic elements(PTEs)and improving water quality in karst ecosystems.However,it remains uncertain whether the niche differentiation among moss species influences their capacity for the retention of PTEs.This study examines the petrifying spring-moss system in Tongren Grand Canyon,Guizhou Province,a typical karst region in southwestern China.Four dominant moss species with distinct ecological niches were selected for this study.Inductively coupled plasma mass spectrometry(ICPMS)was used to quantify PTEs in the petrifying springmoss systems and their associated water flows.Ecological niche analysis was integrated to evaluate the PTEs enrichment efficiencies of different petrifying spring-moss systems.The results identified Fissidens grandifrons Brid.,Hydrogonium majusculum(C.Muell.)Chen,Brachythecium curtum(Lindb.)Limpr.,and Cratoneuron filicinum(Hedw.)Spruc.var.filicinum as representative species of distinct ecological niches.After filtration through the petrifying spring-moss systems,the concentrations of PTEs in the water were significantly reduced(P<0.05).The retention capacities of moss species varied significantly across ecological niches and were ranked as follows:C.filicinum var.filicinum>B.curtum>F.grandifrons>H.majusculum.This study demonstrates that karst petrifying spring-moss systems efficiently intercept PTEs in groundwater and reveals,from a niche theory angle,the link between moss niche differentiation and their retention efficiency,which offers innovative strategies for ecological remediation of PTEs pollution in global karst groundwater systems.展开更多
Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators du...Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators due to generally low primary productivity and pronounced seasonal fluctuation in food availability. Consequentially, niche segregation in sympatric breeding seabirds is expected to occur as a mechanism to maintain species coexistence. However, a single-dimensional study on seabird niche segregation might result in unclear niche overlap. Here, we investigated multi-dimensional niche segregation of tropical seabirds during field expeditions to the Xisha Archipelago, China, in 2023. We reconfirmed the breeding status of six species of terns and noddy, and further revealed the multi-dimensional niche segregation among Black-naped (Sterna sumatrana), Bridled (Onychoprion anaethetus) and Roseate (Sterna dougallii) Terns. Spatially, these three species utilized nest sites that differentiated by vegetation and distance to sea. Temporally, Black-naped Terns bred earlier and for a longer period, while Bridled and Roseate Terns had more restricted breeding seasons. Furthermore, the daily foraging activity patterns of these species also differed, with Bridled Terns potentially having a longer foraging time at noon. In terms of diet, Bridled Terns were opportunists that fed on fishes, squids and insects, such as migratory fruit-piercing moths, while Roseate Terns were primarily piscivorous, especially feeding on Exocoetidae (flying fishes). Seabirds play a crucial role in marine ecosystems and are globally threatened. Our findings shed light on the complex mechanisms facilitating the coexistence of sympatric seabird species in China. Further research is needed to examine other ecological interactions and to develop effective conservation strategies for protecting these valuable seabird populations.展开更多
Background:The traditional Chinese medicine compound Sancao decoction(SCD)is a folk prescription for regulating immunity.It is composed of 8 Chinese herbal medicines,such as Prunellae Spica(Xiakucao),Houttuyniae Herba...Background:The traditional Chinese medicine compound Sancao decoction(SCD)is a folk prescription for regulating immunity.It is composed of 8 Chinese herbal medicines,such as Prunellae Spica(Xiakucao),Houttuyniae Herba(Yuxingcao),Lysimachiae Herba(Jinqiancao)and so on.In cancer,the interleukin-6(IL-6)/the signal transducer and the activator of transcription 3(STAT3)pathway directly promotes the proliferation,survival and angiogenesis of cancer cells,and arginase-1(ARG-1)is a key enzyme for myeloid-derived suppressor cells(MDSCs)to exert immunosuppressive function.It is not clear whether SCD regulates the expression of ARG-1 in MDSCs through the IL-6/STAT3 pathway.Therefore,we explored the effect and mechanism of SCD on lung metastasis of breast cancer.Methods:The components in SCD have been analyzed by HPLC-MS.A spontaneous metastasis model of breast cancer was established by injecting 4T1 cells into the mammary fat pad of BALB/c mice.Pre-metastatic niche(PMN)formation and the role of SCD on PMN were evaluated by lung metastasis nodules,lung pathology tests and immunofluorescence for 2–4 weeks.Serum tests and hematoxylin-eosin staining(H&E)were used to evaluate the side effects of cisplatin.Western blot and ELISA were used to detect proteins and cytokines of the STAT3 signaling pathway in mouse lung tissue.Results:Compared with SCD or cisplatin treatment alone,SCD/cisplatin(CP)synergistic administration not only significantly inhibited orthotropic breast tumor growth,but also reduced lung metastasis and alleviated the hepatorenal toxicity induced by CP in vivo.Remarkably,the combination effectively inhibited PMN formation and the accumulation of MDSCs in the lung PMN,accompanied by the significant infiltration of CD4+T and CD8+T-lymphocytes in the lung PMN and spleen.In addition,the SCD/CP combination downregulated protein expression levels of STAT3,p-STAT3,IL-6 and ARG-1 in the lung PMN of breast cancer mice.Conclusion:The synergistic effect of SCD and cisplatin inhibited MDSCs aggregation and the immunosuppressive function of pulmonary PMN,thereby remodeling the immunosuppressive tumor microenvironment and enhancing anti-tumor immunity,leading to remission of orthotopic breast cancer and lung metastases and amelioration of cisplatin-induced liver and kidney toxicity.展开更多
Subterranean environments are buffered from external climatic fluctuations due to the absence of light and a delayed thermal response to surface conditions(Mammola 2019).Terrestrial salamanders are often found in subt...Subterranean environments are buffered from external climatic fluctuations due to the absence of light and a delayed thermal response to surface conditions(Mammola 2019).Terrestrial salamanders are often found in subterranean habitats,but few studies have assessed the influence of climatic effects on their long-term spatial distribution and niche breadth.In this study,we investigated the variability over 29 consecutive years of the spatial niche in a terrestrial salamander population inhabiting an artificial subterranean habitat.We hypothesized that juvenile salamanders,which are typically active near cave entrances and more exposed to climatic variability and dehydration(Peterman et al.2013),would exhibit an earlier and more variable behavioral adaptation to increasing external temperatures compared to adults.展开更多
Habitat fragmentation poses a significant threat to bird communities, especially those in open and semi-open ecosystems such as steppes. This study investigates how steppe birds adapt to and utilize fragmented habitat...Habitat fragmentation poses a significant threat to bird communities, especially those in open and semi-open ecosystems such as steppes. This study investigates how steppe birds adapt to and utilize fragmented habitats by combining niche modeling with ecological trait analysis. We conducted standardized point surveys to examine the habitat preferences of 32 bird species in Inner Mongolia, China, and quantified their habitat niche parameters using the Outlying Mean Index (OMI). Our results reveal distinct habitat preferences among species, with some thriving in intact environments while others are better adapted to fragmented areas. Grassland species showed high specialization along the fragmentation gradient, while others exhibited adaptability to varying levels of fragmentation. Using a Generalized Additive Model (GAM), we identified three key traits influencing habitat occupancy: hand-wing index, body mass, and range size. Specifically, species with medium hand-wing indices, moderate body mass, and larger range sizes were more likely to occupy heavily fragmented habitats. These findings provide empirical evidence on how habitat fragmentation affects bird species in steppe ecosystems. The study highlights the importance of functional traits in understanding avian responses to habitat fragmentation and offers a foundation for developing effective conservation strategies to preserve biodiversity in fragmented landscapes.展开更多
Accurate traffic flow prediction has a profound impact on modern traffic management. Traffic flow has complex spatial-temporal correlations and periodicity, which poses difficulties for precise prediction. To address ...Accurate traffic flow prediction has a profound impact on modern traffic management. Traffic flow has complex spatial-temporal correlations and periodicity, which poses difficulties for precise prediction. To address this problem, a Multi-head Self-attention and Spatial-Temporal Graph Convolutional Network (MSSTGCN) for multiscale traffic flow prediction is proposed. Firstly, to capture the hidden traffic periodicity of traffic flow, traffic flow is divided into three kinds of periods, including hourly, daily, and weekly data. Secondly, a graph attention residual layer is constructed to learn the global spatial features across regions. Local spatial-temporal dependence is captured by using a T-GCN module. Thirdly, a transformer layer is introduced to learn the long-term dependence in time. A position embedding mechanism is introduced to label position information for all traffic sequences. Thus, this multi-head self-attention mechanism can recognize the sequence order and allocate weights for different time nodes. Experimental results on four real-world datasets show that the MSSTGCN performs better than the baseline methods and can be successfully adapted to traffic prediction tasks.展开更多
Two widespread bird species in Sri Lanka’s dry zone,Pycnonotus cafer(Red-vented Bulbul,RVBB)and Pycnonotus luteolus(White-browed Bulbul,WBBB),were studied to understand their foraging dynamics and ecology.The researc...Two widespread bird species in Sri Lanka’s dry zone,Pycnonotus cafer(Red-vented Bulbul,RVBB)and Pycnonotus luteolus(White-browed Bulbul,WBBB),were studied to understand their foraging dynamics and ecology.The research was conducted from October 2022 to February 2023 in Mihintale Sanctuary(80.30′11.24″E,8.21′04.63″N)and the Faculty of Applied Sciences,Rajarata University of Sri Lanka(80.502206″E,8.353090″N).Data were obtained through focal sampling,opportunistic observations,and mist netting.Both species predominantly foraged on twigs,using gleaning as the dominant food-handling technique.RVBB foraged mostly at the canopy level,while WBBB foraged primarily at the sub-canopy level.Fruits constituted the major food type for both species.RVBB and WBBB utilized 10 and 7 plant species,respectively,with Grewia helicterifolia being the primary foraging plant.Minimal foraging was observed on Croton sp.(RVBB)and Hugonia mistax(WBBB).The correlation between nutritional components and the consumption of both species revealed a preference for foods with lower protein,higher fat,and ash content.There was no linear correlation between gape width and fruit size(r=-0.21,P=0.69)for both species.The standardized dietary niche breadth indicated both species are specialists,with a high pairwise dietary niche overlap(0.9854).These findings highlight the niche-specific foraging adaptations of RVBB and WBBB within Mihintale,emphasizing their distinct strategies in utilizing plant species,fruit sizes,and foraging heights.Understanding such ecological dynamics is essential for habitat conservation efforts and ensuring the availability of key foraging resources for these species in the dry zone.展开更多
As global warming persistently alters and rapidly reshapes landscapes and habitats, conventional species distribution models relying solely on maintaining static conditions within the current climate are likely to fal...As global warming persistently alters and rapidly reshapes landscapes and habitats, conventional species distribution models relying solely on maintaining static conditions within the current climate are likely to falter, particularly at the genus level. Hence, we hypothesize that climate change will differentially affect ecological niches of the same genus species with various latitudinal positioning and local topography, and the high-latitude species may experience greater niche contraction than low-latitude species, and that mountainous regions with high elevational variability may serve as critical climate refugia. Herein, we simulate niche alterations and integrate an ensemble model(EM) strategy, taking into account species dispersal limitations factors(topography, soil, and ultraviolet), to construct a comprehensive habitat suitability(CHS) model for assessing the future vulnerability of the Betula genus, most of which are timber species in China. Our findings reveal that the niche spatial(geographic distribution) of most species(62%) within the Betula genus will undergo a gradual decline under climate change, supporting our hypothesis of latitudinal differentiation in climate vulnerability. Intriguingly, the projected high-latitude niche reduction within the genus cannot be counterbalanced by the anticipated niche expansion of closely related species in low-latitude regions, even considering the evident latitudinal gradient distribution of species. Nonetheless, the niche spatial of six Betula species in southwestern China remains stable or expands under warming scenarios, strongly supporting our secondary hypothesis about topographic buffering effects, which probably means the unique topography(i.e., the largest elevation difference) of this region may serve as a sanctuary for preserving Betula genetic diversity. Our results underscore the uncertain nature of pre-existing niche systems at the genus level under climate change, emphasizing the need for diligent resource management and conservation planning for vulnerable timber species.展开更多
The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined ...The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined in herbs,shrubs,and trees,and less commonly studied in interlayer plant taxa.Here we examined evolutionary processes that resulted in the PID of a pantropical woody liana,Uncaria(Rubiaceae).We first constructed a comprehensive phylogeny by employing 73 plastid protein-coding sequences from 29 accessions of Uncaria(including 16 newly sequenced)from different continents.We then inferred divergence time,history and ecological niche evolution of this genus.Our results showed that Uncaria consisted of four well-supported clades that belonged to two geographically distinct lineages:the Asia-Oceania lineage and the Afro-Neotropical lineage.Biogeographic reconstruction showed this genus likely originated in Asia during the early Miocene(ca.19.03 Ma)and the Middle Miocene Climatic Optimum may have triggered the early diversification of Uncaria.Due to its recent origin and small seeds with long wings,wind or water-mediated long-distance dispersal may have contributed to the distribution of Uncaria in tropical Oceania(via stepping-stone dispersal)and tropical Africa and America(by transoceanic dispersal).Our findings also indicate that diversification of Uncaria was primarily driven by ecological niche divergence,particularly climatic factors.Our study emphasizes the dual role of climatic niche divergence and long-distance dispersal in shaping the PID of Uncaria,providing references for many other extant lineages with similar distributions.展开更多
Amid global precipitation changes,it remains unclear whether hydrological niche separation(HNS)mechanisms apply to herbaceous plant communities in desert steppes are severely affected by seasonal drought.How these pla...Amid global precipitation changes,it remains unclear whether hydrological niche separation(HNS)mechanisms apply to herbaceous plant communities in desert steppes are severely affected by seasonal drought.How these plants access limited water and tolerate drought to coexist also remains unverified.In this study,we employed stable isotope techniques to examine water acquisition and drought adaptation in coexisting species of the desert steppe in northern China under five precipitation treatments,i.e.,decreased 50%,decreased 30%,ambient,increased 30%,and increased 50%precipitation.The following results showed that:(1)water sources of coexisting species shifted with changes in precipitation amount and timing,i.e.,all coexisting plants exhibited preferential utilization of surface soil moisture.When surface soil moisture was scarce,they shifted to deeper water sources,and when deep water sources remained scarce,they were forced to compete more intensely for surface water sources;(2)community's HNS was affected by precipitation amount but not by timing,i.e.,with adequate soil moisture,plant water source ranges expanded,reducing overlap and enhancing HNS,whereas under extreme drought,the range contracted and increased the overlap,although HNS remained stable;and(3)water acquisition strategies of coexisting species differed along hydrological niche axis defined by water stress adaptability(i.e.,stable carbon isotope composition and proline content).Convolvulus ammannii Desr.had the strongest drought adaptation,although its strategy showed a weak correlation with water uptake.Stipa breviflora Griseb.,with moderate drought resistance,adopted a water-conserving strategy that was suitable for extreme drought.Leymus secalinus(Georgi)Tzvelev,Polygala tenuifolia Willd.,and Larix potaninii Batalin showed resource-dependent and flexible water strategies,thriving in wetter soils but struggling under extreme drought.Our findings indicated that herbaceous species in desert steppes adapted their water uptake and drought tolerance strategies according to changes in precipitation amount and timing.As a core regulatory mechanism,HNS(under increasing precipitation variability due to climate change)not only supports species coexistence by reducing interspecific competition,but also promotes efficient soil moisture use.This mechanism enhances community drought resistance and contributes to ecosystem stability.Overall,this study provides key ecological evidence for understanding plant community adaptation in arid and semi-arid areas facing the influence of global climate change.展开更多
The expansion of the scale of the elderly care industry,the acquisition of market share,and the seizure of high profits depend on the consistency between the ecological niche of the elderly care industry and the actua...The expansion of the scale of the elderly care industry,the acquisition of market share,and the seizure of high profits depend on the consistency between the ecological niche of the elderly care industry and the actual resource and environmental conditions.Based on the situation theory of ecological niche,this paper expands the factor of“energy”and represents the three dimensions of“state,”“potential,”and“energy”from three aspects:market niche,technology niche,and resource niche.Taking 220 listed companies as samples,this paper improves the traditional catastrophe progression evaluation model and uses structural equation modeling to test the validity of the indicator system,thereby conducting evaluation research on the ecological niche of the elderly care industry.From the results of niche potential energy measurement,the three dimensions of market niche,resource niche,and technology niche are unevenly developed,reflecting the lack of competitiveness of the elderly care industry.展开更多
Spatial-temporal traffic prediction technology is crucial for network planning,resource allocation optimizing,and user experience improving.With the development of virtual network operators,multi-operator collaboratio...Spatial-temporal traffic prediction technology is crucial for network planning,resource allocation optimizing,and user experience improving.With the development of virtual network operators,multi-operator collaborations,and edge computing,spatial-temporal traffic data has taken on a distributed nature.Consequently,noncentralized spatial-temporal traffic prediction solutions have emerged as a recent research focus.Currently,the majority of research typically adopts federated learning methods to train traffic prediction models distributed on each base station.This method reduces additional burden on communication systems.However,this method has a drawback:it cannot handle irregular traffic data.Due to unstable wireless network environments,device failures,insufficient storage resources,etc.,data missing inevitably occurs during the process of collecting traffic data.This results in the irregular nature of distributed traffic data.Yet,commonly used traffic prediction models such as Recurrent Neural Networks(RNN)and Long Short-Term Memory(LSTM)typically assume that the data is complete and regular.To address the challenge of handling irregular traffic data,this paper transforms irregular traffic prediction into problems of estimating latent variables and generating future traffic.To solve the aforementioned problems,this paper introduces split learning to design a structured distributed learning framework.The framework comprises a Global-level Spatial structure mining Model(GSM)and several Nodelevel Generative Models(NGMs).NGM and GSM represent Seq2Seq models deployed on the base station and graph neural network models deployed on the cloud or central controller.Firstly,the time embedding layer in NGM establishes the mapping relationship between irregular traffic data and regular latent temporal feature variables.Secondly,GSM collects statistical feature parameters of latent temporal feature variables from various nodes and executes graph embedding for spatial-temporal traffic data.Finally,NGM generates future traffic based on latent temporal and spatial feature variables.The introduction of the time attention mechanism enhances the framework’s capability to handle irregular traffic data.Graph attention network introduces spatially correlated base station traffic feature information into local traffic prediction,which compensates for missing information in local irregular traffic data.The proposed framework effectively addresses the distributed prediction issues of irregular traffic data.By testing on real world datasets,the proposed framework improves traffic prediction accuracy by 35%compared to other commonly used distributed traffic prediction methods.展开更多
Anthropogenic disturbances are causing significant impacts on plant distribution worldwide,and many of these effects are driven by changes in the recruitment patterns of plant species.Global warming and land-use chang...Anthropogenic disturbances are causing significant impacts on plant distribution worldwide,and many of these effects are driven by changes in the recruitment patterns of plant species.Global warming and land-use change are two major disturbances leading to changes in germination strategies by changing both soil temperature regimes and light quality reaching the seeds due to soil disturbance.Investigating the range,overlap,and redundancy of niche germination of co-occurring plant species allows us to understand whether endemic species are threatened either by native non-endemic or by alien species,especially in an ecosystem of restricted distribution such as the campo rupestre.Employing a systematic review,this study aimed to evaluate the effect of temperature increase and seed burial on the germination of endemic and non-endemic species in the campo rupestre in Brazil.We performed a metaanalysis using increased temperature and darkness as proxies for the impact of disturbance on germination patterns.In this context,we hypothesized that:increased temperature and darkness negatively influence the germination of native species and positively influence the germination of alien species in the campo rupestre.Specifically,we expect the negative effect to be more pronounced in endemic species than in native non-endemic species.Moreover,we intend to describe the role of seed size in the germination of native and alien species from campo rupestre in the context of increased temperature and darkness.Our analysis showed that increased temperature influenced the germination of alien species by ca.55%,while it did not influence the germination of endemic or native non-endemic species.Furthermore,the germination of alien species under higher temperatures was promoted by increasing seed size.Darkness negatively influenced seed germination of native species,independent of their distribution.Moreover,under darkness conditions,the germination of endemic seeds decreased with seed size.Through their direct effects on germination strategies,we conclude that warming temperatures and land-use change can lead to a long-term displacement of endemic species by native non-endemic and alien species in campo rupestre,thus compromising ecosystem services and conservation of these fragile physiognomies in the near future.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U19A2044,42105132,42030609,41975037,and 42105133)the National Key Research and Development Program of China(No.2022YFC3703502)+1 种基金the Plan for Anhui Major Provincial Science&Technology Project(No.202203a07020003)Hefei Ecological Environment Bureau Project(No.2020BFFFD01804).
文摘As a significant city in the Yangtze River Delta regions,Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion.However,there has been limited research in recent years on the spatial-temporal distribution and emission of its atmospheric pollutants.To address this,this study conducted mobile observations of urban roads using the Mobile-DOAS instrument from June 2021 to May 2022.The monitoring results exhibit a favourable consistent with TROPOMI satellite data and ground monitoring station data.Temporally,there were pronounced seasonal variations in air pollutants.Spatially,high concentration of HCHO and NO_(2)were closely associated with traffic congestion on roadways,while heightened SO_(2)levels were attributed to winter heating and industrial emissions.The study also revealed that with the implementation of road policies,the average vehicle speed increased by 95.4%,while the NO concentration decreased by 54.4%.In the estimation of urban NO_(x)emission flux,it was observed that in temporal terms,compared with inventory data,the emissions calculated viamobile measurements exhibitedmore distinct seasonal patterns,with the highest emission rate of 349 g/sec in winter and the lowest of 142 g/sec in summer.In spatial terms,the significant difference in emissions between the inner and outer ring roads also suggests the presence of the city’s primary NO_(x)emission sources in the area between these two rings.This study offers data support for formulating the next phase of air pollution control measures in urban areas.
文摘[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.
基金supported by the National Natural Science Foundation of China(32271584 and 31600445)the Natural Science Basic Research Plan in Shaanxi Province of China(2020JM-286)+2 种基金the Fundamental Research Funds for the Central Universities(GK202103072 and GK202103073)the Key Research and Development Program of Shaanxi Province(2025SF-YBXM-514)Special Research Project in Philosophy and Social Sciences of Shaanxi Province(2022HZ1795).
文摘Predicting whether alien species will invade a native community is a key challenge in invasion ecology.One factor that may help predict invasion success is phylogenetic relatedness.Darwin proposed that closely related species tend to share similar niches,although this relationship may be influenced by various ecological and evolutionary factors.To test this,we classified alien Asteraceae species in China into three categories based on their invasion status and the extent of ecological damage:introduced,naturalized,and invasive.We then compared the genetic relationships and niche overlap between alien and native Asteraceae species.We found that invasive Asteraceae species are more closely related to native Asteraceae species than are introduced and naturalized species.However,alien Asteraceae species(including introduced,naturalized,and invasive species)exhibited relatively low niche overlap with native Asteraceae species.These findings suggest that the main premise underlying Darwin’s naturalization conundrum,namely,the universality of phylogenetic niche conservatism,may not hold true.Instead,our findings indicate that alien species are more likely to invade successfully when they are more closely related to native plants,exhibit less niche overlap,and maintain conservative niches during the invasion process.These findings provide new insights into the mechanisms of alien plant invasions,highlight the relationship between alien species invasions and native community vulnerability,and offer important insights into the development of effective biological invasion management strategies.
基金supported by the National Office for Philosophy and Social Sciences(grant reference 22&ZD067).
文摘In the current situation of decelerating economic expansion,examining the digital economy(DE)as a novel economic model is beneficial for the local economy’s sustainable and high-quality development(HQD).We analyzed panel data from the Yellow River(YR)region from 2013 to 2021 and discovered notable spatial variances in the composite index and coupling coordination of the two systems.Specifically,the downstream region exhibited the highest coupling coordination,while the upstream region had the lowest.We identified that favorable factors such as economic development,innovation,industrial upgrading,and government intervention can bolster the coupling.Our findings provide a valuable framework for promoting DE and HQD in the YR region.
基金supported by the National Key Research&Development Project of China(Grant No.2016YFC0402209)and the China Scholarship Council.
文摘Accurate capture and presentation of the interactive feedback relationships among various objectives in multi-objective reservoir operation is essential for maximizing operational benefits.In this study,the niche theory of ecology was innovatively applied to the field of reservoir operation,and a novel state-relationship(S-R)measurement analysis method was developed for multi-objective reservoir operation.This method enables the study of interaction among multiple objectives.This method was used to investigate the relationship among the objectives of power generation,water supply,and ecological protection for cascade reservoir operation in the Wujiang River Basin in China.The results indicated that the ecological protection objective was the most competitive in acquiring and capturing resources like flow and water level,while the water supply objective was the weakest.Power generation competed most strongly with ecological protection and relatively weakly with water supply.These findings facilitate decision-making throughout the reservoir operation process in the region.The S-R method based on the niche theory is convenient,efficient,and intuitive,allowing for the quantification of feedback relationships among objectives without requiring the solution of the Pareto frontier of a multi-objective problem in advance.This method provides a novel and feasible idea for studying multi-objective interactions.
基金supported by the National Natural Science Foundation of China (No.32201304)the Fundamental Research Funds for the Central Universities (No.2412022QD026)。
文摘The transformation of natural habitats into human-modified landscapes has far-reaching consequences for species distribution and abundance.As species adapt to these changing environments,shifts in distribution patterns,niche dynamics,and interspecies interactions may occur,impacting biodiversity at multiple levels and potentially leading to ecosystem imbalances.This study aims to assess the impact of variations in vegetation composition and human disturbance on the distribution of sympatric breeding birds and to determine the extent of niche overlap or differentiation among these species.We conducted field surveys and collected data on bird distribution,vegetation composition,and level of human disturbance in eastern Inner Mongolian grasslands.We focused on the six most frequently co-occurring breeding birds,representing a mix of sparrows,larks,and corvids.Generalized Additive Models revealed varying responses of species occurrence along habitat gradients.Species like the Eurasian Skylark(Alauda arvensis),Mongolian Lark(Melanocorypha mongolica),and Asian Shorttoed Lark(Calandrella cheleensis),increased in larger and more connected habitats,while others,like the Tree Sparrow(Passer montanus),Eurasian Magpie(Pica pica),and Barn Swallow(Hirundo rustica),adapted to more fragmented habitats.Niche analysis indicated habitat generalists tended to occupy larger niches than grassland specialists.Substantial niche overlap was also found among the six co-occurring bird species.Conservation efforts should consider the specific needs of specialist species and strive to maintain or restore critical grassland habitats.Additionally,promoting sustainable agricultural practices that balance the needs of birds and human activities can contribute to the coexistence of generalist and specialist bird species in modified landscapes.
基金the National Nature Science Foundation of China(No.32360052)the Department of Science and Technology Foundation of Guizhou Province,China[No.2017(5742)]。
文摘Urbanization and industrialization have heightened the risk of groundwater contamination in karst regions,threatening the safety of petrifying spring water.Petrifying spring-moss systems serve as critical interfaces for groundwater-surface water interaction,retaining potentially toxic elements(PTEs)and improving water quality in karst ecosystems.However,it remains uncertain whether the niche differentiation among moss species influences their capacity for the retention of PTEs.This study examines the petrifying spring-moss system in Tongren Grand Canyon,Guizhou Province,a typical karst region in southwestern China.Four dominant moss species with distinct ecological niches were selected for this study.Inductively coupled plasma mass spectrometry(ICPMS)was used to quantify PTEs in the petrifying springmoss systems and their associated water flows.Ecological niche analysis was integrated to evaluate the PTEs enrichment efficiencies of different petrifying spring-moss systems.The results identified Fissidens grandifrons Brid.,Hydrogonium majusculum(C.Muell.)Chen,Brachythecium curtum(Lindb.)Limpr.,and Cratoneuron filicinum(Hedw.)Spruc.var.filicinum as representative species of distinct ecological niches.After filtration through the petrifying spring-moss systems,the concentrations of PTEs in the water were significantly reduced(P<0.05).The retention capacities of moss species varied significantly across ecological niches and were ranked as follows:C.filicinum var.filicinum>B.curtum>F.grandifrons>H.majusculum.This study demonstrates that karst petrifying spring-moss systems efficiently intercept PTEs in groundwater and reveals,from a niche theory angle,the link between moss niche differentiation and their retention efficiency,which offers innovative strategies for ecological remediation of PTEs pollution in global karst groundwater systems.
基金founded by National Natural Science Foundation of China (Grant Number:32370545)Marine Protected Area Administration of Sansha City (Monitoring seabird spatial-temporal dynamic project in Sansha City)Science and Technology Planning Projects of Guangdong Province, Grant Number:2021B1212110002
文摘Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators due to generally low primary productivity and pronounced seasonal fluctuation in food availability. Consequentially, niche segregation in sympatric breeding seabirds is expected to occur as a mechanism to maintain species coexistence. However, a single-dimensional study on seabird niche segregation might result in unclear niche overlap. Here, we investigated multi-dimensional niche segregation of tropical seabirds during field expeditions to the Xisha Archipelago, China, in 2023. We reconfirmed the breeding status of six species of terns and noddy, and further revealed the multi-dimensional niche segregation among Black-naped (Sterna sumatrana), Bridled (Onychoprion anaethetus) and Roseate (Sterna dougallii) Terns. Spatially, these three species utilized nest sites that differentiated by vegetation and distance to sea. Temporally, Black-naped Terns bred earlier and for a longer period, while Bridled and Roseate Terns had more restricted breeding seasons. Furthermore, the daily foraging activity patterns of these species also differed, with Bridled Terns potentially having a longer foraging time at noon. In terms of diet, Bridled Terns were opportunists that fed on fishes, squids and insects, such as migratory fruit-piercing moths, while Roseate Terns were primarily piscivorous, especially feeding on Exocoetidae (flying fishes). Seabirds play a crucial role in marine ecosystems and are globally threatened. Our findings shed light on the complex mechanisms facilitating the coexistence of sympatric seabird species in China. Further research is needed to examine other ecological interactions and to develop effective conservation strategies for protecting these valuable seabird populations.
基金supported by Fundamental Research Funds for the Central Universities(ZYN2024075)Chengdu Science and Technology Bureau Technology Innovation R&D Project(2024-YF05-02236-SN)the Applied Basic Research Project of the Sichuan Science Technology Department(2021YJ0256).Peer review information。
文摘Background:The traditional Chinese medicine compound Sancao decoction(SCD)is a folk prescription for regulating immunity.It is composed of 8 Chinese herbal medicines,such as Prunellae Spica(Xiakucao),Houttuyniae Herba(Yuxingcao),Lysimachiae Herba(Jinqiancao)and so on.In cancer,the interleukin-6(IL-6)/the signal transducer and the activator of transcription 3(STAT3)pathway directly promotes the proliferation,survival and angiogenesis of cancer cells,and arginase-1(ARG-1)is a key enzyme for myeloid-derived suppressor cells(MDSCs)to exert immunosuppressive function.It is not clear whether SCD regulates the expression of ARG-1 in MDSCs through the IL-6/STAT3 pathway.Therefore,we explored the effect and mechanism of SCD on lung metastasis of breast cancer.Methods:The components in SCD have been analyzed by HPLC-MS.A spontaneous metastasis model of breast cancer was established by injecting 4T1 cells into the mammary fat pad of BALB/c mice.Pre-metastatic niche(PMN)formation and the role of SCD on PMN were evaluated by lung metastasis nodules,lung pathology tests and immunofluorescence for 2–4 weeks.Serum tests and hematoxylin-eosin staining(H&E)were used to evaluate the side effects of cisplatin.Western blot and ELISA were used to detect proteins and cytokines of the STAT3 signaling pathway in mouse lung tissue.Results:Compared with SCD or cisplatin treatment alone,SCD/cisplatin(CP)synergistic administration not only significantly inhibited orthotropic breast tumor growth,but also reduced lung metastasis and alleviated the hepatorenal toxicity induced by CP in vivo.Remarkably,the combination effectively inhibited PMN formation and the accumulation of MDSCs in the lung PMN,accompanied by the significant infiltration of CD4+T and CD8+T-lymphocytes in the lung PMN and spleen.In addition,the SCD/CP combination downregulated protein expression levels of STAT3,p-STAT3,IL-6 and ARG-1 in the lung PMN of breast cancer mice.Conclusion:The synergistic effect of SCD and cisplatin inhibited MDSCs aggregation and the immunosuppressive function of pulmonary PMN,thereby remodeling the immunosuppressive tumor microenvironment and enhancing anti-tumor immunity,leading to remission of orthotopic breast cancer and lung metastases and amelioration of cisplatin-induced liver and kidney toxicity.
文摘Subterranean environments are buffered from external climatic fluctuations due to the absence of light and a delayed thermal response to surface conditions(Mammola 2019).Terrestrial salamanders are often found in subterranean habitats,but few studies have assessed the influence of climatic effects on their long-term spatial distribution and niche breadth.In this study,we investigated the variability over 29 consecutive years of the spatial niche in a terrestrial salamander population inhabiting an artificial subterranean habitat.We hypothesized that juvenile salamanders,which are typically active near cave entrances and more exposed to climatic variability and dehydration(Peterman et al.2013),would exhibit an earlier and more variable behavioral adaptation to increasing external temperatures compared to adults.
基金supported by the National Natural Science Foundation of China(No.32201304)the Fundamental Research Funds for the Central Universities(No.2412022QD026).
文摘Habitat fragmentation poses a significant threat to bird communities, especially those in open and semi-open ecosystems such as steppes. This study investigates how steppe birds adapt to and utilize fragmented habitats by combining niche modeling with ecological trait analysis. We conducted standardized point surveys to examine the habitat preferences of 32 bird species in Inner Mongolia, China, and quantified their habitat niche parameters using the Outlying Mean Index (OMI). Our results reveal distinct habitat preferences among species, with some thriving in intact environments while others are better adapted to fragmented areas. Grassland species showed high specialization along the fragmentation gradient, while others exhibited adaptability to varying levels of fragmentation. Using a Generalized Additive Model (GAM), we identified three key traits influencing habitat occupancy: hand-wing index, body mass, and range size. Specifically, species with medium hand-wing indices, moderate body mass, and larger range sizes were more likely to occupy heavily fragmented habitats. These findings provide empirical evidence on how habitat fragmentation affects bird species in steppe ecosystems. The study highlights the importance of functional traits in understanding avian responses to habitat fragmentation and offers a foundation for developing effective conservation strategies to preserve biodiversity in fragmented landscapes.
基金supported by the National Natural Science Foundation of China(Grant Nos.62472149,62376089,62202147)Hubei Provincial Science and Technology Plan Project(2023BCB04100).
文摘Accurate traffic flow prediction has a profound impact on modern traffic management. Traffic flow has complex spatial-temporal correlations and periodicity, which poses difficulties for precise prediction. To address this problem, a Multi-head Self-attention and Spatial-Temporal Graph Convolutional Network (MSSTGCN) for multiscale traffic flow prediction is proposed. Firstly, to capture the hidden traffic periodicity of traffic flow, traffic flow is divided into three kinds of periods, including hourly, daily, and weekly data. Secondly, a graph attention residual layer is constructed to learn the global spatial features across regions. Local spatial-temporal dependence is captured by using a T-GCN module. Thirdly, a transformer layer is introduced to learn the long-term dependence in time. A position embedding mechanism is introduced to label position information for all traffic sequences. Thus, this multi-head self-attention mechanism can recognize the sequence order and allocate weights for different time nodes. Experimental results on four real-world datasets show that the MSSTGCN performs better than the baseline methods and can be successfully adapted to traffic prediction tasks.
文摘Two widespread bird species in Sri Lanka’s dry zone,Pycnonotus cafer(Red-vented Bulbul,RVBB)and Pycnonotus luteolus(White-browed Bulbul,WBBB),were studied to understand their foraging dynamics and ecology.The research was conducted from October 2022 to February 2023 in Mihintale Sanctuary(80.30′11.24″E,8.21′04.63″N)and the Faculty of Applied Sciences,Rajarata University of Sri Lanka(80.502206″E,8.353090″N).Data were obtained through focal sampling,opportunistic observations,and mist netting.Both species predominantly foraged on twigs,using gleaning as the dominant food-handling technique.RVBB foraged mostly at the canopy level,while WBBB foraged primarily at the sub-canopy level.Fruits constituted the major food type for both species.RVBB and WBBB utilized 10 and 7 plant species,respectively,with Grewia helicterifolia being the primary foraging plant.Minimal foraging was observed on Croton sp.(RVBB)and Hugonia mistax(WBBB).The correlation between nutritional components and the consumption of both species revealed a preference for foods with lower protein,higher fat,and ash content.There was no linear correlation between gape width and fruit size(r=-0.21,P=0.69)for both species.The standardized dietary niche breadth indicated both species are specialists,with a high pairwise dietary niche overlap(0.9854).These findings highlight the niche-specific foraging adaptations of RVBB and WBBB within Mihintale,emphasizing their distinct strategies in utilizing plant species,fruit sizes,and foraging heights.Understanding such ecological dynamics is essential for habitat conservation efforts and ensuring the availability of key foraging resources for these species in the dry zone.
基金funded by the National Science Foundation for Young Scientists of China(No.32001327)the National Key Research and Development Program of China(No.2021YFD2200304-2).
文摘As global warming persistently alters and rapidly reshapes landscapes and habitats, conventional species distribution models relying solely on maintaining static conditions within the current climate are likely to falter, particularly at the genus level. Hence, we hypothesize that climate change will differentially affect ecological niches of the same genus species with various latitudinal positioning and local topography, and the high-latitude species may experience greater niche contraction than low-latitude species, and that mountainous regions with high elevational variability may serve as critical climate refugia. Herein, we simulate niche alterations and integrate an ensemble model(EM) strategy, taking into account species dispersal limitations factors(topography, soil, and ultraviolet), to construct a comprehensive habitat suitability(CHS) model for assessing the future vulnerability of the Betula genus, most of which are timber species in China. Our findings reveal that the niche spatial(geographic distribution) of most species(62%) within the Betula genus will undergo a gradual decline under climate change, supporting our hypothesis of latitudinal differentiation in climate vulnerability. Intriguingly, the projected high-latitude niche reduction within the genus cannot be counterbalanced by the anticipated niche expansion of closely related species in low-latitude regions, even considering the evident latitudinal gradient distribution of species. Nonetheless, the niche spatial of six Betula species in southwestern China remains stable or expands under warming scenarios, strongly supporting our secondary hypothesis about topographic buffering effects, which probably means the unique topography(i.e., the largest elevation difference) of this region may serve as a sanctuary for preserving Betula genetic diversity. Our results underscore the uncertain nature of pre-existing niche systems at the genus level under climate change, emphasizing the need for diligent resource management and conservation planning for vulnerable timber species.
基金funded equally by grants from the National Natural Science Foundation of China(32322006 and 32100187)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2024QZKK0200)+5 种基金by the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U23A20149)the Key R&D Program of Yunnan Province(202103AF140005 and 202101BC070002)the Yunnan Provincial Science and Technology Talent and Platform Plan(202305AM070005)the Key Specialized Research and Development Breakthrough Program in Henan Province(232102110237)the Natural Science Foundation of Henan Province(242300421572)the Strategic Biological Resources Capacity Building Project of Chinese Academy of Sciences(KFJ-BRP-017-08).
文摘The formation of pantropical intercontinental disjunction(PID)in plants has generally been attributed to vicariance,boreotropical migration,and long-distance dispersal.However,this pattern has primarily been examined in herbs,shrubs,and trees,and less commonly studied in interlayer plant taxa.Here we examined evolutionary processes that resulted in the PID of a pantropical woody liana,Uncaria(Rubiaceae).We first constructed a comprehensive phylogeny by employing 73 plastid protein-coding sequences from 29 accessions of Uncaria(including 16 newly sequenced)from different continents.We then inferred divergence time,history and ecological niche evolution of this genus.Our results showed that Uncaria consisted of four well-supported clades that belonged to two geographically distinct lineages:the Asia-Oceania lineage and the Afro-Neotropical lineage.Biogeographic reconstruction showed this genus likely originated in Asia during the early Miocene(ca.19.03 Ma)and the Middle Miocene Climatic Optimum may have triggered the early diversification of Uncaria.Due to its recent origin and small seeds with long wings,wind or water-mediated long-distance dispersal may have contributed to the distribution of Uncaria in tropical Oceania(via stepping-stone dispersal)and tropical Africa and America(by transoceanic dispersal).Our findings also indicate that diversification of Uncaria was primarily driven by ecological niche divergence,particularly climatic factors.Our study emphasizes the dual role of climatic niche divergence and long-distance dispersal in shaping the PID of Uncaria,providing references for many other extant lineages with similar distributions.
基金funded by the National Natural Science Foundation of China(32160406).
文摘Amid global precipitation changes,it remains unclear whether hydrological niche separation(HNS)mechanisms apply to herbaceous plant communities in desert steppes are severely affected by seasonal drought.How these plants access limited water and tolerate drought to coexist also remains unverified.In this study,we employed stable isotope techniques to examine water acquisition and drought adaptation in coexisting species of the desert steppe in northern China under five precipitation treatments,i.e.,decreased 50%,decreased 30%,ambient,increased 30%,and increased 50%precipitation.The following results showed that:(1)water sources of coexisting species shifted with changes in precipitation amount and timing,i.e.,all coexisting plants exhibited preferential utilization of surface soil moisture.When surface soil moisture was scarce,they shifted to deeper water sources,and when deep water sources remained scarce,they were forced to compete more intensely for surface water sources;(2)community's HNS was affected by precipitation amount but not by timing,i.e.,with adequate soil moisture,plant water source ranges expanded,reducing overlap and enhancing HNS,whereas under extreme drought,the range contracted and increased the overlap,although HNS remained stable;and(3)water acquisition strategies of coexisting species differed along hydrological niche axis defined by water stress adaptability(i.e.,stable carbon isotope composition and proline content).Convolvulus ammannii Desr.had the strongest drought adaptation,although its strategy showed a weak correlation with water uptake.Stipa breviflora Griseb.,with moderate drought resistance,adopted a water-conserving strategy that was suitable for extreme drought.Leymus secalinus(Georgi)Tzvelev,Polygala tenuifolia Willd.,and Larix potaninii Batalin showed resource-dependent and flexible water strategies,thriving in wetter soils but struggling under extreme drought.Our findings indicated that herbaceous species in desert steppes adapted their water uptake and drought tolerance strategies according to changes in precipitation amount and timing.As a core regulatory mechanism,HNS(under increasing precipitation variability due to climate change)not only supports species coexistence by reducing interspecific competition,but also promotes efficient soil moisture use.This mechanism enhances community drought resistance and contributes to ecosystem stability.Overall,this study provides key ecological evidence for understanding plant community adaptation in arid and semi-arid areas facing the influence of global climate change.
基金Natural Science Foundation Project of Hebei Provincial Science and Technology Department(G2023415001)Humanities and Social Sciences Research Project of Colleges and Universities in Hebei Province(SD2021084)The 2025 Hebei Province Social Science Development Research Project titled“Practical Research on Hebei Province’s Undertaking of the Elderly Care Service Industry from Beijing and Tianjin under the Collaborative Development of the Beijing-Tianjin-Hebei Region”。
文摘The expansion of the scale of the elderly care industry,the acquisition of market share,and the seizure of high profits depend on the consistency between the ecological niche of the elderly care industry and the actual resource and environmental conditions.Based on the situation theory of ecological niche,this paper expands the factor of“energy”and represents the three dimensions of“state,”“potential,”and“energy”from three aspects:market niche,technology niche,and resource niche.Taking 220 listed companies as samples,this paper improves the traditional catastrophe progression evaluation model and uses structural equation modeling to test the validity of the indicator system,thereby conducting evaluation research on the ecological niche of the elderly care industry.From the results of niche potential energy measurement,the three dimensions of market niche,resource niche,and technology niche are unevenly developed,reflecting the lack of competitiveness of the elderly care industry.
基金supported by the Beijing Natural Science Foundation(Certificate Number:L234025).
文摘Spatial-temporal traffic prediction technology is crucial for network planning,resource allocation optimizing,and user experience improving.With the development of virtual network operators,multi-operator collaborations,and edge computing,spatial-temporal traffic data has taken on a distributed nature.Consequently,noncentralized spatial-temporal traffic prediction solutions have emerged as a recent research focus.Currently,the majority of research typically adopts federated learning methods to train traffic prediction models distributed on each base station.This method reduces additional burden on communication systems.However,this method has a drawback:it cannot handle irregular traffic data.Due to unstable wireless network environments,device failures,insufficient storage resources,etc.,data missing inevitably occurs during the process of collecting traffic data.This results in the irregular nature of distributed traffic data.Yet,commonly used traffic prediction models such as Recurrent Neural Networks(RNN)and Long Short-Term Memory(LSTM)typically assume that the data is complete and regular.To address the challenge of handling irregular traffic data,this paper transforms irregular traffic prediction into problems of estimating latent variables and generating future traffic.To solve the aforementioned problems,this paper introduces split learning to design a structured distributed learning framework.The framework comprises a Global-level Spatial structure mining Model(GSM)and several Nodelevel Generative Models(NGMs).NGM and GSM represent Seq2Seq models deployed on the base station and graph neural network models deployed on the cloud or central controller.Firstly,the time embedding layer in NGM establishes the mapping relationship between irregular traffic data and regular latent temporal feature variables.Secondly,GSM collects statistical feature parameters of latent temporal feature variables from various nodes and executes graph embedding for spatial-temporal traffic data.Finally,NGM generates future traffic based on latent temporal and spatial feature variables.The introduction of the time attention mechanism enhances the framework’s capability to handle irregular traffic data.Graph attention network introduces spatially correlated base station traffic feature information into local traffic prediction,which compensates for missing information in local irregular traffic data.The proposed framework effectively addresses the distributed prediction issues of irregular traffic data.By testing on real world datasets,the proposed framework improves traffic prediction accuracy by 35%compared to other commonly used distributed traffic prediction methods.
基金financial support from CNPq/Peld CRSC,Fapemig,CAPES,Anglo American,and Vale.
文摘Anthropogenic disturbances are causing significant impacts on plant distribution worldwide,and many of these effects are driven by changes in the recruitment patterns of plant species.Global warming and land-use change are two major disturbances leading to changes in germination strategies by changing both soil temperature regimes and light quality reaching the seeds due to soil disturbance.Investigating the range,overlap,and redundancy of niche germination of co-occurring plant species allows us to understand whether endemic species are threatened either by native non-endemic or by alien species,especially in an ecosystem of restricted distribution such as the campo rupestre.Employing a systematic review,this study aimed to evaluate the effect of temperature increase and seed burial on the germination of endemic and non-endemic species in the campo rupestre in Brazil.We performed a metaanalysis using increased temperature and darkness as proxies for the impact of disturbance on germination patterns.In this context,we hypothesized that:increased temperature and darkness negatively influence the germination of native species and positively influence the germination of alien species in the campo rupestre.Specifically,we expect the negative effect to be more pronounced in endemic species than in native non-endemic species.Moreover,we intend to describe the role of seed size in the germination of native and alien species from campo rupestre in the context of increased temperature and darkness.Our analysis showed that increased temperature influenced the germination of alien species by ca.55%,while it did not influence the germination of endemic or native non-endemic species.Furthermore,the germination of alien species under higher temperatures was promoted by increasing seed size.Darkness negatively influenced seed germination of native species,independent of their distribution.Moreover,under darkness conditions,the germination of endemic seeds decreased with seed size.Through their direct effects on germination strategies,we conclude that warming temperatures and land-use change can lead to a long-term displacement of endemic species by native non-endemic and alien species in campo rupestre,thus compromising ecosystem services and conservation of these fragile physiognomies in the near future.
