We obtai ned geo-refere need occurre nee and climatic data from in dividual localities for 59 species of terrestrial elapid snakes, used phylogenetic generalized least squares regression to investigate spatial and cla...We obtai ned geo-refere need occurre nee and climatic data from in dividual localities for 59 species of terrestrial elapid snakes, used phylogenetic generalized least squares regression to investigate spatial and cladistic patter ns of variation in climatic niche breadths, and compared patter ns within and across regions and clades to see if they parallel or differ from each other. Specifically, we test (1) whether a species' climatic niche breadth on a given niche axis relates to its position along that axis, and to its climatic niche breadth on another niche axis, and (2) whether variation in niche breadths among species is explained by within-locality variation in climatic conditions or by among-locality variation. We found that:(1) there is an overall global patter n, and patter ns in individual regi ons or clades gen erally parallel each other and global patter ns;(2) species in wanner environments have narrower temperature niche breadths (TNBs);(3) precipitation niche breadth (PNB) and position are positively related;⑷ TNB and PNB are not related;and ⑸ within-locality variation in climatic conditions explains most variation in TNBs, whereas among-locality variation explains most variation in PNBs. Our results are consistent with those reported for lizards of the families Phrynosomatidae and Varanidae, con firm the importance of withi n-locality n iche breadth to species n iche breadth, and show a more im porta nt role of amon g-locality n iche breadth in affecting species niche breadth in terrestrial elapids than in lizards.展开更多
Measuring climatic niche position and breadth may help to determine where species can occur over space and time. Using GIS-based and phylogenetic comparative methods, we investigated global patterns of variation in cl...Measuring climatic niche position and breadth may help to determine where species can occur over space and time. Using GIS-based and phylogenetic comparative methods, we investigated global patterns of variation in climatic niche breadth in lacertid lizards to test the following three hypotheses about climatic niche widths. First, does a species' temperature or precipitation niche breadth relate to its temperature or precipitation niche position(the mean value of annual mean temperature or annual precipitation across sampled localities in the range of each species)? Second, are there trade-offs between a species' temperature niche breadth and precipitation niche breadth? Third, does a species' temperature or precipitation niche breadth relate to altitude or latitude? We expect that:(1) species distributed in cold regions are specialized for low-temperature environments(i.e. narrow niche breadth center around low temperatures);(2) a negative relationship between species niche breadth on temperature and precipitation axes according to the tradeoff hypothesis(i.e. species that tolerate a broad range of precipitation regimes cannot also tolerate a broad range of temperatures);(3) precipitation niche breadth decreases with altitude or latitude, whereas temperature climatic niche breadth increases with altitude or latitude. Based on the analytical results we found that:(1) temperature niche breadth and position are negatively related, while precipitation niche breadth and position are positively related;(2) there is no trade-off between temperature and precipitation niche breadths; and (3) temperature niche breadth and latitude/altitude are positively related, but precipitation niche breadth and latitude/altitude are not significantly related. Our results show many similarities with previous studies on climatic niche widths reported for amphibians and lizards, which provide further evidence that such macroecological patterns of variation in climatic niche breadths may be widespread.展开更多
The climatic niche is a central concept for understanding species distribution,with current and past climate interpreted as strong drivers of present and historical-geographical ranges.Our aim is to understand whether...The climatic niche is a central concept for understanding species distribution,with current and past climate interpreted as strong drivers of present and historical-geographical ranges.Our aim is to understand whether Atlantic Forest snakes follow the general geographical pattern of increasing species climatic niche breadths with increasing latitude.We also tested if there is a tradeoff between temperature and precipitation niche breadths of species in order to understand if species with larger breadths of one niche dimension have stronger dispersal constraints by the other due to narrower niche breadths.Niche breadths were calculated by the subtraction of maximal and minimal values of temperature and precipitation across species ranges.We implemented Phylogenetic Generalized Least Squares to measure the relationship between temperature and precipitation niche breadths and latitude.We also tested phylogenetic signals by Lambda statistics to analyze the degree of phylogenetic niche conservatism to both niche dimensions.Temperature niche breadths were not related to latitude.Precipitation niche breadths decreased with increasing latitude and presented a high phylogenetic signal,that is,significant phylogenetic niche conservatism.We rejected the tradeoff hypotheses of temperature and precipitation niche breadths.Our results also indicate that precipitation should be an important ecological constraint affecting the geographical distribution of snake lineages across the South American Atlantic Forest.We then provide a general view of how phylogenetic niche conservatism could impact the patterns of latitudinal variation of climatic niches across this biodiversity hotspot.展开更多
Many small Parks inKenyaare being fenced to control human-wildlife conflict. Some of these Parks have a diversity of large herbivores which might increase in density in the wake of fencing and subsequent compression o...Many small Parks inKenyaare being fenced to control human-wildlife conflict. Some of these Parks have a diversity of large herbivores which might increase in density in the wake of fencing and subsequent compression of their home ranges due to closure of their migratory routes. It is important to understand the consequences of such an increase on the structuring of insularised herbivore assemblages in such Parks. We studied seasonal resource segregation and niche breadth variation as mechanisms of coexistence in a high density grazer assemblage inLakeNakuruNational Parkwhich is small and completely fenced. Diet composition and habitat use were considered as variables of resource use. We predicted that overlap in resource use and niche breadth would be the smallest among grazers with similar body weights in the dry season which is the most resource limiting for grazers in East Africa. Our results were contrary to the predictions because of lack of seasonal differentiation in the overlap of diet composition and habitat use, and in niche breadth. Overlaps in resource use were consistently high during both the wet and dry seasons, and niche breadth contraction during the dry season was not possible probably because of lack of species-specific niches during the dry season. Our results suggest that there might be competitive interactions in this grazer assemblage which is an important parameter to consider in the management of the Park.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
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
[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
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
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
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
The advantage of Chinese-as-a-heritage-language(CHL)learners in acquiring Chinese has been widely recognized.However,it is still unclear whether the effect of CHL background on Chinese receptive vocabulary breadth var...The advantage of Chinese-as-a-heritage-language(CHL)learners in acquiring Chinese has been widely recognized.However,it is still unclear whether the effect of CHL background on Chinese receptive vocabulary breadth varies across different countries.To address this gap,the present study recruited 232 Chinese language learners(half were CHL learners)from Indonesia and Thailand and administered a Chinese vocabulary proficiency test.The results of regression analysis revealed an interaction effect between country and CHL background on vocabulary breadth,with the contribution of CHL background to vocabulary breadth more robust in the Indonesian group than that in the Thai group.Interviews were then conducted to explore the factors that might influence such an interaction effect.Analysis of the interview data found that the influencing factors could be categorized into four themes,including individual differences,family background,Chinese language education and socio-cultural factors.The overall results were discussed within the framework of ecological system theory,and pedagogical implications for CHL learners were proposed.展开更多
基金the Natural Science Foundation of Zhejiang Province to L.-H.L.(LY17C030003)National Natural Science Foundation of China to X.J.(31272294 and 30770378).
文摘We obtai ned geo-refere need occurre nee and climatic data from in dividual localities for 59 species of terrestrial elapid snakes, used phylogenetic generalized least squares regression to investigate spatial and cladistic patter ns of variation in climatic niche breadths, and compared patter ns within and across regions and clades to see if they parallel or differ from each other. Specifically, we test (1) whether a species' climatic niche breadth on a given niche axis relates to its position along that axis, and to its climatic niche breadth on another niche axis, and (2) whether variation in niche breadths among species is explained by within-locality variation in climatic conditions or by among-locality variation. We found that:(1) there is an overall global patter n, and patter ns in individual regi ons or clades gen erally parallel each other and global patter ns;(2) species in wanner environments have narrower temperature niche breadths (TNBs);(3) precipitation niche breadth (PNB) and position are positively related;⑷ TNB and PNB are not related;and ⑸ within-locality variation in climatic conditions explains most variation in TNBs, whereas among-locality variation explains most variation in PNBs. Our results are consistent with those reported for lizards of the families Phrynosomatidae and Varanidae, con firm the importance of withi n-locality n iche breadth to species n iche breadth, and show a more im porta nt role of amon g-locality n iche breadth in affecting species niche breadth in terrestrial elapids than in lizards.
基金Financial support was provided by grants from Zhejiang Provincial Natural Science Foundation (LY17C030003)Natural Science Foundation of China (31270571)Science and Technology Bureau of Sanya (2013YD08)
文摘Measuring climatic niche position and breadth may help to determine where species can occur over space and time. Using GIS-based and phylogenetic comparative methods, we investigated global patterns of variation in climatic niche breadth in lacertid lizards to test the following three hypotheses about climatic niche widths. First, does a species' temperature or precipitation niche breadth relate to its temperature or precipitation niche position(the mean value of annual mean temperature or annual precipitation across sampled localities in the range of each species)? Second, are there trade-offs between a species' temperature niche breadth and precipitation niche breadth? Third, does a species' temperature or precipitation niche breadth relate to altitude or latitude? We expect that:(1) species distributed in cold regions are specialized for low-temperature environments(i.e. narrow niche breadth center around low temperatures);(2) a negative relationship between species niche breadth on temperature and precipitation axes according to the tradeoff hypothesis(i.e. species that tolerate a broad range of precipitation regimes cannot also tolerate a broad range of temperatures);(3) precipitation niche breadth decreases with altitude or latitude, whereas temperature climatic niche breadth increases with altitude or latitude. Based on the analytical results we found that:(1) temperature niche breadth and position are negatively related, while precipitation niche breadth and position are positively related;(2) there is no trade-off between temperature and precipitation niche breadths; and (3) temperature niche breadth and latitude/altitude are positively related, but precipitation niche breadth and latitude/altitude are not significantly related. Our results show many similarities with previous studies on climatic niche widths reported for amphibians and lizards, which provide further evidence that such macroecological patterns of variation in climatic niche breadths may be widespread.
基金Fundação de AmparoàPesquisa do Estado de São Paulo(FAPESP procs.2008/50068-2,2014/23677-9 and 2020/12658-4)Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq,405447/2016-7)RJS thanks CNPq for the research fellowship(312795/2018-1).
文摘The climatic niche is a central concept for understanding species distribution,with current and past climate interpreted as strong drivers of present and historical-geographical ranges.Our aim is to understand whether Atlantic Forest snakes follow the general geographical pattern of increasing species climatic niche breadths with increasing latitude.We also tested if there is a tradeoff between temperature and precipitation niche breadths of species in order to understand if species with larger breadths of one niche dimension have stronger dispersal constraints by the other due to narrower niche breadths.Niche breadths were calculated by the subtraction of maximal and minimal values of temperature and precipitation across species ranges.We implemented Phylogenetic Generalized Least Squares to measure the relationship between temperature and precipitation niche breadths and latitude.We also tested phylogenetic signals by Lambda statistics to analyze the degree of phylogenetic niche conservatism to both niche dimensions.Temperature niche breadths were not related to latitude.Precipitation niche breadths decreased with increasing latitude and presented a high phylogenetic signal,that is,significant phylogenetic niche conservatism.We rejected the tradeoff hypotheses of temperature and precipitation niche breadths.Our results also indicate that precipitation should be an important ecological constraint affecting the geographical distribution of snake lineages across the South American Atlantic Forest.We then provide a general view of how phylogenetic niche conservatism could impact the patterns of latitudinal variation of climatic niches across this biodiversity hotspot.
基金Kenya Wildlife Service for giving permission to conduct this study in Lake Nakuru National Park,and to the Netherlands Organisation for International Cooperation in Higher Education(NUFFIC)for funding the study
文摘Many small Parks inKenyaare being fenced to control human-wildlife conflict. Some of these Parks have a diversity of large herbivores which might increase in density in the wake of fencing and subsequent compression of their home ranges due to closure of their migratory routes. It is important to understand the consequences of such an increase on the structuring of insularised herbivore assemblages in such Parks. We studied seasonal resource segregation and niche breadth variation as mechanisms of coexistence in a high density grazer assemblage inLakeNakuruNational Parkwhich is small and completely fenced. Diet composition and habitat use were considered as variables of resource use. We predicted that overlap in resource use and niche breadth would be the smallest among grazers with similar body weights in the dry season which is the most resource limiting for grazers in East Africa. Our results were contrary to the predictions because of lack of seasonal differentiation in the overlap of diet composition and habitat use, and in niche breadth. Overlaps in resource use were consistently high during both the wet and dry seasons, and niche breadth contraction during the dry season was not possible probably because of lack of species-specific niches during the dry season. Our results suggest that there might be competitive interactions in this grazer assemblage which is an important parameter to consider in the management of the Park.
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.
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.
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 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.
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 National Social Science Fund of China(No.24BYY048)International Chinese Language Education Research Program(No.23YH17B)Fundamental Research Funds for the Central Universities(No.23JNLH10)。
文摘The advantage of Chinese-as-a-heritage-language(CHL)learners in acquiring Chinese has been widely recognized.However,it is still unclear whether the effect of CHL background on Chinese receptive vocabulary breadth varies across different countries.To address this gap,the present study recruited 232 Chinese language learners(half were CHL learners)from Indonesia and Thailand and administered a Chinese vocabulary proficiency test.The results of regression analysis revealed an interaction effect between country and CHL background on vocabulary breadth,with the contribution of CHL background to vocabulary breadth more robust in the Indonesian group than that in the Thai group.Interviews were then conducted to explore the factors that might influence such an interaction effect.Analysis of the interview data found that the influencing factors could be categorized into four themes,including individual differences,family background,Chinese language education and socio-cultural factors.The overall results were discussed within the framework of ecological system theory,and pedagogical implications for CHL learners were proposed.
