Since 2015, green tides have been blooming in offshore waters of Qinhuangdao, with serious impacts on the local ecological environment and tourism. Ulva australis, Bryopsis plumosa, and U. prolifera are the dominant s...Since 2015, green tides have been blooming in offshore waters of Qinhuangdao, with serious impacts on the local ecological environment and tourism. Ulva australis, Bryopsis plumosa, and U. prolifera are the dominant species of Qinhuangdao green tides, following a sequential succession pattern. Ulva prolifera is the dominant species,with the highest biomass and the greatest influence on the local ecological environment. To study the reason of green tide dominant species succession and U. profilera became the dominant species with the largest biomass,we compared and analyzed the growth and nutrient uptake capacity of the three algae. The results showed that temperature significantly affects the growth of the three species. Within the temperature range of the experimental setup, the optimum temperature for the growth of U. australis, B. plumosa and U. profilera is10℃, 15℃, and 20–25℃, respectively. Combined with the temperature variation trend during green tide bloom development, we believe that temperature is the key environmental factor for the succession of the dominant species. Ulva prolifera has a higher growth rate than U. australis and B. plumosa under the same nitrate,ammonium, and phosphate levels. Significant differences in the maximum absorption rate(R_(max)) and R_(max)/Ks(the relationship between uptake rate and substrate concentration) values indicated that U. prolifera had an apparent competitive advantage over U. australis and B. plumosa regarding nutrient uptake. Therefore, the strong growth and nutrient uptake capacities of U. prolifera might be the main reason for becoming the dominant species with the largest biomass in Qinhuangdao green tides.展开更多
The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evo...The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.展开更多
Since 2015,green tides with Ulva prolifera as the dominant species in the Qinhuangdao coastal waters have continued to occur.In this study,the relationship between green tides in Qinhuangdao and the Yellow Sea(setting...Since 2015,green tides with Ulva prolifera as the dominant species in the Qinhuangdao coastal waters have continued to occur.In this study,the relationship between green tides in Qinhuangdao and the Yellow Sea(setting sites in Rudong and Qingdao)was evaluated by genetic analyses of U.prolifera.Single nucleotide polymorphism(SNP)markers were used to analyze genetic diversity and genetic relationships among groups.Genetic differentiation was lower among floating U.prolifera populations in Rudong and Qingdao than in Qinhuangdao.The floating U.prolifera population had higher genetic diversity and polymorphism levels in Qingdao and Rudong than in Qinhuangdao.Physiological experiments showed that the growth rate and net buoyancy of floating U.prolifera were highest in Qinhuangdao and Qingdao,respectively,under the same environmental conditions(temperature and light).Overall,these findings showed that U.prolifera populations in the Qinhuangdao and Yellow Sea green tides(Rudong and Qingdao)differ significantly at the molecular and physiological levels.Therefore,the Qinhuangdao green tide is not correlated with the Yellow Sea green tide and has a different origin and development mode.This study provides insight into the mechanism underlying green tide blooms in coastal waters of China.展开更多
Aims The relationship between biodiversity and ecosystem functioning has intrigued ecologists for several decades,but the effect of loss of a dominant species on community structure and functioning along a nutrient gr...Aims The relationship between biodiversity and ecosystem functioning has intrigued ecologists for several decades,but the effect of loss of a dominant species on community structure and functioning along a nutrient gradient remains poorly understood.The aim of this paper was to test the effect of a dominant species on community structure and function by conducting a species removal experiment along a fertilization gradient.Methods We removed the population of a dominant species(Elymus nutans)in a long-term fertilization field in an alpine meadow on the Tibetan Plateau,China.univariate general linear models were used to evaluate the effects of fertilization and removal on above-ground vegetation characteristics,including photosynthetically active radiation in the understory,species richness,shannon-Weiner diversity index,simpson’s dominance index,above-ground biomass(includ-ing different functional groups)and seedling richness and density.Important Findingsresults revealed that after two plant growing seasons,there was no significant effect of the removal of a dominant species on species richness and diversity of the remaining vegetation,but the biomass of forbs and seedling recruitment were significantly increased indicative of the potential for long-term effects.moreover,removal had a large effect at high fertilization levels,but little effect when fertilization levels were low.our studies indicated that community response to loss of a dominant species was mainly dependent on resource availability and the remaining functional group identities.We also found seedling recruitment was usually more sensitive to the influence of competition of dominant species than the estab-lished vegetation in the short term.展开更多
Spatial patterns of plant species and patchy community are important properties in grasslands.However,research regarding spatial patterns of formed patches with various species has not fully advanced until now.Our pur...Spatial patterns of plant species and patchy community are important properties in grasslands.However,research regarding spatial patterns of formed patches with various species has not fully advanced until now.Our purpose is to clarify differences in spatial pattern formed by species and community constructed under shady and terrace habitats.The three common Kobresia-Carex patches(Size 1,0.6–0.9 m^(2);Size 2,3.0–3.8 m^(2) and Size 3,6.5–8.8 m^(2))were selected in shady and terrace on the Qinghai-Tibetan Plateau,and corresponding quadrats of 1m1m,2m2m and 3m3m were placed for S1,S2 and S3 patches,respectively.The surveyed quadrats were divided into 20cm20cm large cells(L-cells),and further divided into four 10cm10cm small cells(S-cells).We used the binary occurrence system(presence/absence data)to record occurrences of all species in S-cells.The analysis shows that the power law model was well able to determine the spatial distribution pattern of species or patchy community in shady and terrace.All species and patches show aggregated distribution in shady and terrace habitats.In the shady habitat,the relative spatial heterogeneity(ε)of individual plant species was lowest at presence frequency(P)of 0.1–0.3,whereas in the terrace habitatεwas lowest at P<0.1,andεincreased monotonically with increasing P.For most dominant species,P andεvalues were higher in terrace than those in shady.We concluded that the dominant species largely determine spatial heterogeneity of the Kobresia-Carex patches,while companion and rare species have weak influence on the community-level heterogeneity in shady and terrace habitats.展开更多
The estuarine areas are under frequent influence from freshwater intrusion and ocean currents,in which zooplankton species are diversified and variable as they are sensitive to physio-chemical variations in water.Ther...The estuarine areas are under frequent influence from freshwater intrusion and ocean currents,in which zooplankton species are diversified and variable as they are sensitive to physio-chemical variations in water.Therefore,understanding the relationships between zooplankton and environmental factors help us know the water quality.To achieve co-existence with species in similar ecological group or habit,they could inevitably alter themselves to fit the ecology and adjust the function according to the competitive exclusion in ecological theory.However,information of the co-existence of dominant species in the Changjiang(Yangtze)River estuary(CRE)and adjacent waters remains scarce.We explored the relationships between dominant zooplankton and environmental factors in the study region in spring-summer from 2016 to 2020,involving particularly the composition of dominant species,ecological groups,their relationships with environmental factors,and co-existence of important species,using the non-multidimensional scale analysis(nMDS)method and redundancy analysis.Results show that Labidocera euchaeta and Tortanus vermiculus were dominant species in the study scope.The turnover rate of dominant zooplankton was greater(>50%)in spring while the species number was higher in summer.The dominant species were estuarine,offshore,and eurytopic based on the adaptation to salinity.In spring,the ecological groups were dominated by estuarine species,while in summer by estuarine and offshore species.In addition,the nMDS showed that the dominant species in the same ecological group were more dispersed and not prominently clustered;the dominant species were staggered among different ecological groups.The temperature,salinity,pH,dissolved oxygen,and chlorophyll a were the main environmental factors on the distribution of the dominant species in spring,while in summer were dissolved oxygen,temperature,salinity,and pH.The domination of medusae of Nemopsis bachei and Pleurobrachia globosa in zooplankton community in spring,and the continuous decrease in abundance of L.euchaeta reflected the effects of local climate change.The temperature and salinity changes in different years and the subsequent response of zooplankton reflected the influence of freshwater intrusion and/or ocean currents.Zooplankton in similar ecological habits exhibited the competitive exclusion in terms of co-existence.展开更多
Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection...Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.展开更多
It is widely acknowledged that the distribution of macrobenthos is affected by salinity, but the degree of influence varies in different areas. To explore the distribution pattern of macrobenthic assemblages in the Ha...It is widely acknowledged that the distribution of macrobenthos is affected by salinity, but the degree of influence varies in different areas. To explore the distribution pattern of macrobenthic assemblages in the Hangzhou Bay,12 stations were sampled to collect macrobenthos and the corresponding bottom water. Changes in the general characteristics of macrobenthos along the salinity gradient in the Hangzhou Bay and its adjacent waters were considered. Three dominant species were identified, including the polychaetes Sternaspis chinensis, the crustacea Oratosquilla oratoria and the echinoderm Ophiuroglypha kinbergi. And the macrobenthic assemblages showed a zonal distribution along with the salinity change. The correlation analyses showed that salinity, depth,temperature, suspended solids and dissolved oxygen had concurrent significant correlations with carnivorous group, Margalef species richness(d), Brillouin index(H) and Shannon-Wiener diversity index(H'). In light of the strong correlation between salinity and Changjiang River diluted water, which produces considerable disturbances by freshwater inflows, the deposition of suspended solids and the resuspension of seabed sediments,the combined environmental disturbances, instead of salinity alone, should be adopted to explain the zonation distribution pattern of macrobenthic assemblages.展开更多
Arbuscular mycorrhizal(AM)fungi distribute widely in natural habits and play a variety of ecological functions.In order to test the physiological response to salt stress mediated by different AM fungi,Viola prionantha...Arbuscular mycorrhizal(AM)fungi distribute widely in natural habits and play a variety of ecological functions.In order to test the physiological response to salt stress mediated by different AM fungi,Viola prionantha was selected as the host,the dominant AM fungus in the rhizosphere of V.philippica growing in Songnen saline-alkali grassland,Rhizophagus irregularis,and their mixtures were used as inoculants,and NaCl stress was applied after the roots were colonized.The results showed that V.philippica could be colonized by AM fungi in the field and the colonization rate ranged from 73.33%to 96.67%,and Claroideoglomus etunicatum was identified as the dominant AM fungi species in the rhizosphere of V.philippica by morphology combined with sequencing for AM fungal AML1/AML2 target.Inoculation with both the species resulted in the formation of mycorrhizal symbiosis(the colonization rate was more than 70%)and AM fungi significantly enhanced plants’tolerance to salt stress of varying magnitude.Higher activity of antioxidant enzymes and augmented levels of proline and other osmoregulators were observed in AM plants.The content of MDA in CK was higher than that in the inoculations with the stress of 100,200,and 250 mM.All indices except soluble protein content and MDA content were significantly correlated with AM fungal colonization indices.The analysis for different AM fungal effects showed that the mixtures and R.irregularis worked even better than C.etunicatum.These results will provide theoretical support for the exploration and screening of salt-tolerant AM fungi species and also for the application of AM-ornamental plants in saline-alkali urban greening.展开更多
The construction of artificial reefs has unparallelly developed for a few decades in China.Artificial reefs can be used to manage and conserve commercially exploited fish and crustacea.However,their suitability as eco...The construction of artificial reefs has unparallelly developed for a few decades in China.Artificial reefs can be used to manage and conserve commercially exploited fish and crustacea.However,their suitability as ecological niche is poorly characterized.Therefore,in this study,we detected the seasonal variation of community biodiversity and the corresponding driving environmental factors.We also explored the relationships between dominant species and environmental factors to identify appropriate ecological niche areas.Different statistical analysis methods were used to assess species distribution within an artificial reef area in Xixiakou during nine sampling events in four seasons between 2017 and 2018.Non-metric multidimensional scaling(NMDS)and cluster analysis results indicated that the components of community can be divided into two clusters.Complexity of community,which is exhibited by species number,biodiversity,and catch per unit effort(CPUE),was significantly higher in summer than in other seasons.Generalized additive model(GAMs)results revealed the significant effects of temperature and chlorophyll a on the community structure.Sebastes schlegelii,Hexagrammos otakii,Conger myriaster and Charybdis japonica were the dominant species in four seasons.GAMs results indicated that temperature,dissolved oxygen(DO),pH and chlorophyll a affect the CPUE of dominant species significantly.The distinct suitable ecological niche for each dominant species was found in this study.For example,Charybdis japonica preferred to live in the area with 20.7–22.1℃,dissolved oxygen 7.07–7.15 mg L−1 and salinity 31.8–31.9.The results of this study are beneficial to resource conservation and fishery management.展开更多
Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the ...Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the coun-tries with a severe rate of infections due to its abundant pine resources.In this study,nematode-trapping fungi were collected from pine trees in Ninghai City,Zhejiang Prov-ince,which is the key area of pine wilt control in Febru-ary,May,September,October and November.The results showed that nematode-trapping fungi of pine are abundant,especially the number and species detected in each month and are quite different;species of fungi in July,Septem-ber and November were more numerous and had higher separation rates.The dominant species in November was Arthrobotrys oligospora followed by Arthrobotrys cladodes;July and September it was A.cladodes.In each part of the tree,A.cladodes was the most widely distributed with a high separation rate.Therefore,it is the dominant fungal species in the area.Arboreal Bursaphelenchus xylophilus-trapping fungi are dependent on pine wood nematodes,and none were isolated from healthy pine trees.More arboreal B.xylophilus-trapping fungi were found under the bark than in the xylem.There is a close relationship between arboreal B.xylophilus-trapping fungi and pine wood nematodes.How to make use of these resources to reduce the damage of pine wood nematode fusarium is the focus of future research.展开更多
In this paper,the characteristics of the water quality in Yellow River estuary reservoirs were surveyed and the progress of the eutrophication was investigated by observing the behavior of nitrogen and phosphorus.The ...In this paper,the characteristics of the water quality in Yellow River estuary reservoirs were surveyed and the progress of the eutrophication was investigated by observing the behavior of nitrogen and phosphorus.The results showed that the concentration of dissolved inorganic nitrogen and total nitrogen was very high in all the reservoirs,and the level of nitrogen was eutrophic state.According to Vollenweider's type model for phosphorus load,the total phosphorus was close to permissible load in Guangnan and Xinan reservoirs.But sometimes,the total phosphorus exceeded an excessive load in Gengjing reservoir.In Yellow River estuary reservoirs,Cyanobacteria,and Diatom phytoplankton were observed mainly,and the cyanobacteria was a the dominant species in summer.展开更多
The spatial-temporal variation of understory light availability has important influences on species diversity and community assembly.However,the distribution characteristics and influencing factors of understory light...The spatial-temporal variation of understory light availability has important influences on species diversity and community assembly.However,the distribution characteristics and influencing factors of understory light availability have not been fully elucidated,especially in temperate deciduous,broad-leaved forests.In this study,the understory light availability was monitored monthly(May–October)in a temperate deciduous,broad-leaved forest in Henan Province,China.Differences in the light availability among different months and habitat types were statistically analyzed using Kruskal–Wallis method,respectively.Partial least squares path modeling(PLS-PM)was used to explore the direct and/or indirect effects of stand structure,dominant species and topographic factors on the light environment.Results showed that there were differences in light environments among the four habitat types and during the studied six months.The PLS-PM results showed that the stand structure and the dominant species were negatively correlated with the light environment,and the path coefficient values were−0.089(P=0.042)and−0.130(P=0.004),respectively.Our result indicated that the understory light availability exhibit a distinct spatial and temporal heterogeneity in temperate deciduous,broad-leaved forest of north China.The characteristics of woody plant community,especially the abundance of one of the dominant plant species,were the important factors affecting the understory light availability.展开更多
Seasonal variations and causes for these were elaborated for fishery resources in Shenzhen sea area,to provide scientific basis for sustainable utilization and management of fishery resources in typical fisheries of S...Seasonal variations and causes for these were elaborated for fishery resources in Shenzhen sea area,to provide scientific basis for sustainable utilization and management of fishery resources in typical fisheries of South China Sea coasts. Based on the data of fishery resources collected through trawl surveys in Egong Bay fisheries area,Shenzhen,from August( autumn) and December( winter) of 2012 to March(spring) and May(summer) of 2013,seasonal variation of nekton species composition,stock density,dominant species composition,size spectra and biodiversity were studied. Results showed that there were 113 species of nekton in Shenzhen sea area,which belonged to 78 genus,50 families,14 orders and 3 classes. The number of species was the largest in summer(61 species) and smallest in autumn(53 species). In spring and winter,there was 56 species. The stock density and individual density of nekton were the minimum in summer(5950. 20 kg/km2 and 356. 45 ind/km2,respectively),whereas the percentage of fish stock density and individual density were the highest in summer(51. 99%and 42. 19%). The seasonal variations of size spectra indicated that fishing intensity was the highest in autumn,and was the lowest in summer. Additionally,biodiversity index presented significant seasonal variations,including Shannon-Wiener diversity index( H '),Margalef richness index( D') and Pielou evenness index( J'),with the same trend as summer > spring > autumn > winter. In conclusion,there are clear seasonal variations in the nekton species,biomass and structure in Egong Bay fisheries area in Shenzhen. Due to the difference in fishing intensity in different seasons( low intensity in summer and high intensity in autumn),community structure and function in summer are more stable than that in autumn and winter. Particularly,with the increase in the fishing intensity in autumn,k selection species will be replaced by r selection species.展开更多
[Objectives]This study was conducted to identify the pathogen species and dominant species of sugarcane pokkah boeng in main varieties in Yunnan sugarcane areas,so as to promote the healthy and sustainable development...[Objectives]This study was conducted to identify the pathogen species and dominant species of sugarcane pokkah boeng in main varieties in Yunnan sugarcane areas,so as to promote the healthy and sustainable development of sugarcane industry.[Methods]Specific primers Fv-F3/Fv-R3 and Fp-F4/Fp-R4 were designed based on the ribosomal DNA non-internal transcribed spacer(rDNA-ITS)gene sequences of Fusarium verticillioides and Fusarium proliferarum,the main pathogens of sugarcane pokkah boeng,and 117 typical sugarcane pokkah boeng samples collected from main varieties in different sugarcane areas of Yunnan Province were detected and analyzed by PCR.[Results]Among the 117 sugarcane pokkah boeng samples,112 samples were detected with F.verticillioides with a positive detection rate of 95.7%;103 samples were detected with F.proliferarum with a positive detection rate of 88%;103 samples were infected by F.verticillioides+F.proliferarum,and the compound infection rate was 88%;and the two pathogens were not detected in 5 samples,which might be sugarcane pokkah boeng caused by other species.PCR amplification products of 23 F.verticillioides positive samples and 19 F.proliferarum positive samples from different sugarcane varieties in different sugarcane areas were sequenced.The BLAST alignment results showed that the sequences of the 23 amplification products of F.verticillioides shared 99.45%-100.00%homology with F.verticillioides(GenBank accession number:KU508286),and the sequences of the 19 amplification products of F.proliferarum shared 99.26%-100.00%homology with the sequence of F.proliferarum(GenBank accession number:MK252904).Part of the F.verticillioids and 11 F.proliferarum sequences were selected to construct a phylogenetic tree,and the phylogenetic analysis showed that they belonged to the F.verticillioids group and F.proliferarum group,respectively.The results showed that F.verticillioides and F.proliferarum were the main pathogens causing sugarcane pokkah boeng of the main sugarcane varieties in Yunnan,and there was a common phenomenon of compound infection.F.verticillioides was the dominant species in Pu er,Lincang,Honghe and Yuxi sugarcane areas,but the detection rate of F.proliferarum was also high,and there were other species.In the future,the discovery of resistant germplasm resources and breeding of resistant varieties should be carried out aiming at these two pathogens of sugarcane pokkah boeng.[Conclusions]The study provides technical support for rapid identification of sugarcane pokkah boeng pathogens,and scientific basis for breeding resistant varieties and scientific disease prevention and control.展开更多
[Objectives]This study was conducted to determine the pathogen species and dominant species of sugarcane pokkah boeng in the sugarcane areas of Yunnan in the low-latitude plateau,so as to provide a basis for the patho...[Objectives]This study was conducted to determine the pathogen species and dominant species of sugarcane pokkah boeng in the sugarcane areas of Yunnan in the low-latitude plateau,so as to provide a basis for the pathogenic mechanism,disease resistance breeding and scientific prevention and control of pokkah boeng.[Methods]With 14 pokkah boeng samples collected from different sugarcane areas in Yunnan as materials,pokkah boeng-specific detection primers FvF4/Fv-R4 and Fp-F3/Fp-R3 were designed based on ribosomal DNA non-transcribed spacer(rDNA-ITS)sequences,respectively,and used to perform PCR on Fusarium verticillioides and F.proliferatum.[Results]In 12 of the 14 pokkah boeng samples,two species of pokkah boeng pathogens were detected,and there was a phenomenon of composite infection.Seven composite infection samples were selected for sequence alignment and phylogenetic analysis.The sequences of F.verticillioides(Gen Bank accession number:MZ126549-MZ126555)and F.proliferatum(Gen Bank accession number:MZ102259-MZ102265)from seven composite infection samples shared 98.6%-100%and 100%with F.verticillioides strain 20(Gen Bank accession number:KU508286)and F.proliferatum Dehong strain(GenBank accession number:KJ629482)published in Gen Bank,respectively.The phylogenetic tree showed that the pathogens of sugarcane pokkah boeng in Yunnan were mainly divided into the F.verticillioides group and F.proliferatum group.In the F.verticillioides group,except for ROC 25(Lancang,Yunnan)and Funong10-1405(Maitreya,Yunnan)which were on an independent branch,the remaining five composite infection samples were grouped with F.verticillioides strains from different geographical origins,and were closely related to F.oxysporum Guangxi strain.All strains of F.proliferatum from different geographic origins were clustered into another group.[Conclusions]This study provides a scientific basis for disease resistance breeding and disease prevention and control of sugarcane pokkah boeng.展开更多
Forests in Northeast China in the Greater and Lesser Khingan Mountains(GKM and LKM)account for nearly 1/3 of the total state-owned forests in the country.Regional and historical comparisons of forest plants and macrof...Forests in Northeast China in the Greater and Lesser Khingan Mountains(GKM and LKM)account for nearly 1/3 of the total state-owned forests in the country.Regional and historical comparisons of forest plants and macrofungi will favor biological conservation,forest management and economic development.A total of 1067 sampling plots were surveyed on forest composition and structure,with a macrofungi survey at Liangshui and Huzhong Nature Reserves in the center of two regions.Regional and historical differences of these parameters were analyzed with a redundancy ordination of their complex associations.There were 61-76 families,189-196 genera,and 369-384 species,which was only 1/3 of the historical records.The same dominant species were larch and birch with Korean pine(a climax species)less as expected from past surveys in the LKM.Shrub and herb species were different in the two regions,as expected from historical records.There was 10-50%lower species diversity(except for herb evenness),but 1.8-to 4-time higher macrofungi diversity in the GKM.Compared with the LKM,both tree heights and macrofungi density were higher.Nevertheless,current heights averaging 10 m are half of historical records(>20 m in the 1960s).Edible macrofungi were the highest proportion in both regions,about twice that of other fungal groups,hav-ing important roles in the local economy.A major factor explaining plant diversity variations in both regions was herb cover,followed by shrubs in the GKM and herb-dominant species in the LKM.Factors responsible for macrofungi variations were tree density and shrub height.Vaccinium vitis-idaea and Larix gmelinii in the GKM but tree size and diversity were important factors in the LKM.Our findings highlighted large spatial and historical differences between the GKM and LKM in plant-macrofungal composition,forest structure,and their complex associations,which will favor precise conservation and management of forest resources in two region in the future.展开更多
The dominant species of a biome can be regarded as its genuine indicator.Evergreen broadleaved forests(EBLFs) in subtropical East Asia harbor high levels of species biodiversity and endemism and are vital to regional ...The dominant species of a biome can be regarded as its genuine indicator.Evergreen broadleaved forests(EBLFs) in subtropical East Asia harbor high levels of species biodiversity and endemism and are vital to regional carbon storage and cycling.However,the historical assembly of this unique biome is still controversial.Fagaceae is the most essential family in East Asian subtropical EBLFs and its dominant species are vital for the existence of this biome.Here,we used the dominant Fagaceae species to shed light on the dynamic process of East Asian subtropical EBLFs overtime.Our results indicate high precipitation in summer and low temperature in winter are the most influential climatic factors for the distribution of East Asian subtropical EBLFs.Modern East Asian subtropical EBLFs did not begin to appear until 23 Ma,subsequently experienced a longlasting development in the Miocene and markedly deteriorated at about 4 Ma,driven jointly by orogenesis and paleoclimate.We also document that there is a lag time between when one clade invaded the region and when its members become dominant species within the region.This study may improve our ability to predict and mitigate the threats to biodiversity of East Asian subtropical EBLFs and points to a new path for future studies involving multidisciplinary methods to explore the assembly of regional biomes.展开更多
Aims Decades of empirical work have demonstrated how dominant plant species and nitrogen fertilization can influence the structure and function of plant communities.More recent studies have examined the interplay betw...Aims Decades of empirical work have demonstrated how dominant plant species and nitrogen fertilization can influence the structure and function of plant communities.More recent studies have examined the interplay between these factors,but few such studies use an explicit trait-based framework.In this study,we use an explicit trait-based approach to identify potential mechanisms for community-level responses and to test ecological niche theory.Methods We experimentally manipulated plant communities(control,−dom-inant species,−random biomass)and nitrogen(N)inputs(control,+organic N,+inorganic N)in a fully factorial design.We predicted that traits related to plants’ability to take up different forms of soil N would differ between dominant and subordinate species,resulting in interactive effects of dominant species loss and N fertilization on plant community structure and function.The study took place in a montane meadow in the Rocky Mountains,Colorado,USA.Important Findings After four years,the plant community in removal plots converged toward a species composition whose leaf and root functional traits resembled those of the previously removed dominant species.Ecosystem productivity generally increased with N addition:soil carbon efflux was~50%greater when either form of N was added,while inorganic N addition increased aboveground biomass pro-duction by~60%relative to controls.The increase in production was mediated by increased average height,leaf mass:area ratio and leaf dry matter content in plant communities to which we added inorganic N.Contrary to our predictions,there were no interactive effects of N fertilization and dominant species loss on plant com-munity structure or ecosystem function.The plant community com-position in this study exhibited resistance to soil N addition and,given the functional convergence we observed,was resilient to spe-cies loss.Together,our results indicate that the ability of species to compensate functionally for species loss confers resilience and maintains diversity in montane meadow communities.展开更多
Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated ...Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought.Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought,whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought.The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species,and the community biomass resistance and recovery were also greatly driven by the stability of grasses.Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability.Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects.Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.展开更多
基金The Fund of Key Laboratory of Ecological Prewarning,Protection and Restoration of Bohai Sea,Ministry of Natural Resources under contract No.2022107the Qingdao Postdoctoral Applied Research Project under contract No.QDBSH202001。
文摘Since 2015, green tides have been blooming in offshore waters of Qinhuangdao, with serious impacts on the local ecological environment and tourism. Ulva australis, Bryopsis plumosa, and U. prolifera are the dominant species of Qinhuangdao green tides, following a sequential succession pattern. Ulva prolifera is the dominant species,with the highest biomass and the greatest influence on the local ecological environment. To study the reason of green tide dominant species succession and U. profilera became the dominant species with the largest biomass,we compared and analyzed the growth and nutrient uptake capacity of the three algae. The results showed that temperature significantly affects the growth of the three species. Within the temperature range of the experimental setup, the optimum temperature for the growth of U. australis, B. plumosa and U. profilera is10℃, 15℃, and 20–25℃, respectively. Combined with the temperature variation trend during green tide bloom development, we believe that temperature is the key environmental factor for the succession of the dominant species. Ulva prolifera has a higher growth rate than U. australis and B. plumosa under the same nitrate,ammonium, and phosphate levels. Significant differences in the maximum absorption rate(R_(max)) and R_(max)/Ks(the relationship between uptake rate and substrate concentration) values indicated that U. prolifera had an apparent competitive advantage over U. australis and B. plumosa regarding nutrient uptake. Therefore, the strong growth and nutrient uptake capacities of U. prolifera might be the main reason for becoming the dominant species with the largest biomass in Qinhuangdao green tides.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDB31000000the National Natural Science Foundation of China(No.31370267).
文摘The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.
基金The Fund of Key Laboratory of Ecological PrewarningProtection and Restoration of Bohai Sea,Ministry of Natural Resources under contract No.2022107+1 种基金the National Key Research and Development Program of China under contract No.2019YFC1407902the Qingdao Postdoctoral Applied Research Project of China under contract No.QDBSH202001。
文摘Since 2015,green tides with Ulva prolifera as the dominant species in the Qinhuangdao coastal waters have continued to occur.In this study,the relationship between green tides in Qinhuangdao and the Yellow Sea(setting sites in Rudong and Qingdao)was evaluated by genetic analyses of U.prolifera.Single nucleotide polymorphism(SNP)markers were used to analyze genetic diversity and genetic relationships among groups.Genetic differentiation was lower among floating U.prolifera populations in Rudong and Qingdao than in Qinhuangdao.The floating U.prolifera population had higher genetic diversity and polymorphism levels in Qingdao and Rudong than in Qinhuangdao.Physiological experiments showed that the growth rate and net buoyancy of floating U.prolifera were highest in Qinhuangdao and Qingdao,respectively,under the same environmental conditions(temperature and light).Overall,these findings showed that U.prolifera populations in the Qinhuangdao and Yellow Sea green tides(Rudong and Qingdao)differ significantly at the molecular and physiological levels.Therefore,the Qinhuangdao green tide is not correlated with the Yellow Sea green tide and has a different origin and development mode.This study provides insight into the mechanism underlying green tide blooms in coastal waters of China.
基金Key Program of National Natural Science Foundation of China(40930533)Natural Science Foundation of China(41230852)+1 种基金Northwest A&F University(Z109021107,Z109021307,QN2013070)West Light Foundation of Chinese Academy of Sciences(K318021305).
文摘Aims The relationship between biodiversity and ecosystem functioning has intrigued ecologists for several decades,but the effect of loss of a dominant species on community structure and functioning along a nutrient gradient remains poorly understood.The aim of this paper was to test the effect of a dominant species on community structure and function by conducting a species removal experiment along a fertilization gradient.Methods We removed the population of a dominant species(Elymus nutans)in a long-term fertilization field in an alpine meadow on the Tibetan Plateau,China.univariate general linear models were used to evaluate the effects of fertilization and removal on above-ground vegetation characteristics,including photosynthetically active radiation in the understory,species richness,shannon-Weiner diversity index,simpson’s dominance index,above-ground biomass(includ-ing different functional groups)and seedling richness and density.Important Findingsresults revealed that after two plant growing seasons,there was no significant effect of the removal of a dominant species on species richness and diversity of the remaining vegetation,but the biomass of forbs and seedling recruitment were significantly increased indicative of the potential for long-term effects.moreover,removal had a large effect at high fertilization levels,but little effect when fertilization levels were low.our studies indicated that community response to loss of a dominant species was mainly dependent on resource availability and the remaining functional group identities.We also found seedling recruitment was usually more sensitive to the influence of competition of dominant species than the estab-lished vegetation in the short term.
基金funded by The Second Tibetan Plateau Scientific Expedition and Research (STEP)program (Grant No.2019QZKK0305)Youth Science and Technology Fund Program of GanSu (Grant No.22JR5RA083)the National Natural Science Foundation of China (Grant No.31971466).
文摘Spatial patterns of plant species and patchy community are important properties in grasslands.However,research regarding spatial patterns of formed patches with various species has not fully advanced until now.Our purpose is to clarify differences in spatial pattern formed by species and community constructed under shady and terrace habitats.The three common Kobresia-Carex patches(Size 1,0.6–0.9 m^(2);Size 2,3.0–3.8 m^(2) and Size 3,6.5–8.8 m^(2))were selected in shady and terrace on the Qinghai-Tibetan Plateau,and corresponding quadrats of 1m1m,2m2m and 3m3m were placed for S1,S2 and S3 patches,respectively.The surveyed quadrats were divided into 20cm20cm large cells(L-cells),and further divided into four 10cm10cm small cells(S-cells).We used the binary occurrence system(presence/absence data)to record occurrences of all species in S-cells.The analysis shows that the power law model was well able to determine the spatial distribution pattern of species or patchy community in shady and terrace.All species and patches show aggregated distribution in shady and terrace habitats.In the shady habitat,the relative spatial heterogeneity(ε)of individual plant species was lowest at presence frequency(P)of 0.1–0.3,whereas in the terrace habitatεwas lowest at P<0.1,andεincreased monotonically with increasing P.For most dominant species,P andεvalues were higher in terrace than those in shady.We concluded that the dominant species largely determine spatial heterogeneity of the Kobresia-Carex patches,while companion and rare species have weak influence on the community-level heterogeneity in shady and terrace habitats.
基金Supported by the Innovation Team Project of Ecological Environment Monitoring and Restoration of Fishery Waters in the East China Sea of the Chinese Academy of Fishery Sciences(No.2020TD14)the National Basic Research Program of China(973 Program)(No.2010CB429005)。
文摘The estuarine areas are under frequent influence from freshwater intrusion and ocean currents,in which zooplankton species are diversified and variable as they are sensitive to physio-chemical variations in water.Therefore,understanding the relationships between zooplankton and environmental factors help us know the water quality.To achieve co-existence with species in similar ecological group or habit,they could inevitably alter themselves to fit the ecology and adjust the function according to the competitive exclusion in ecological theory.However,information of the co-existence of dominant species in the Changjiang(Yangtze)River estuary(CRE)and adjacent waters remains scarce.We explored the relationships between dominant zooplankton and environmental factors in the study region in spring-summer from 2016 to 2020,involving particularly the composition of dominant species,ecological groups,their relationships with environmental factors,and co-existence of important species,using the non-multidimensional scale analysis(nMDS)method and redundancy analysis.Results show that Labidocera euchaeta and Tortanus vermiculus were dominant species in the study scope.The turnover rate of dominant zooplankton was greater(>50%)in spring while the species number was higher in summer.The dominant species were estuarine,offshore,and eurytopic based on the adaptation to salinity.In spring,the ecological groups were dominated by estuarine species,while in summer by estuarine and offshore species.In addition,the nMDS showed that the dominant species in the same ecological group were more dispersed and not prominently clustered;the dominant species were staggered among different ecological groups.The temperature,salinity,pH,dissolved oxygen,and chlorophyll a were the main environmental factors on the distribution of the dominant species in spring,while in summer were dissolved oxygen,temperature,salinity,and pH.The domination of medusae of Nemopsis bachei and Pleurobrachia globosa in zooplankton community in spring,and the continuous decrease in abundance of L.euchaeta reflected the effects of local climate change.The temperature and salinity changes in different years and the subsequent response of zooplankton reflected the influence of freshwater intrusion and/or ocean currents.Zooplankton in similar ecological habits exhibited the competitive exclusion in terms of co-existence.
基金the Natural Science Foundation of Inner Mongolia,China(2023JQ01)the National Key R&D Program of China(2019YFA0607103)+2 种基金the Central Government Guides Local Science and Technology Development Fund Projects(2022ZY0224)the Open Project Program of Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau,Hohhot,Inner Mongolia,China(KF2023003)Major Science and Technology Project of Inner Mongolia Autonomous Region:Monitoring,Assessment and Early Warning Technology Research of Biodiversity in Inner Mongolia(2021ZD0011)for financial support.
文摘Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.
基金The National Natural Science Foundation of China under contract Nos 42076156 and 41676139the K.C. Wong Magna Fund in Ningbo University。
文摘It is widely acknowledged that the distribution of macrobenthos is affected by salinity, but the degree of influence varies in different areas. To explore the distribution pattern of macrobenthic assemblages in the Hangzhou Bay,12 stations were sampled to collect macrobenthos and the corresponding bottom water. Changes in the general characteristics of macrobenthos along the salinity gradient in the Hangzhou Bay and its adjacent waters were considered. Three dominant species were identified, including the polychaetes Sternaspis chinensis, the crustacea Oratosquilla oratoria and the echinoderm Ophiuroglypha kinbergi. And the macrobenthic assemblages showed a zonal distribution along with the salinity change. The correlation analyses showed that salinity, depth,temperature, suspended solids and dissolved oxygen had concurrent significant correlations with carnivorous group, Margalef species richness(d), Brillouin index(H) and Shannon-Wiener diversity index(H'). In light of the strong correlation between salinity and Changjiang River diluted water, which produces considerable disturbances by freshwater inflows, the deposition of suspended solids and the resuspension of seabed sediments,the combined environmental disturbances, instead of salinity alone, should be adopted to explain the zonation distribution pattern of macrobenthic assemblages.
基金Research was funded by National Natural Science Foundation of China with the Grant No.31601986 and Heilongjiang Postdoctoral Scientific Research Developmental Fund(LBH-Q16005).
文摘Arbuscular mycorrhizal(AM)fungi distribute widely in natural habits and play a variety of ecological functions.In order to test the physiological response to salt stress mediated by different AM fungi,Viola prionantha was selected as the host,the dominant AM fungus in the rhizosphere of V.philippica growing in Songnen saline-alkali grassland,Rhizophagus irregularis,and their mixtures were used as inoculants,and NaCl stress was applied after the roots were colonized.The results showed that V.philippica could be colonized by AM fungi in the field and the colonization rate ranged from 73.33%to 96.67%,and Claroideoglomus etunicatum was identified as the dominant AM fungi species in the rhizosphere of V.philippica by morphology combined with sequencing for AM fungal AML1/AML2 target.Inoculation with both the species resulted in the formation of mycorrhizal symbiosis(the colonization rate was more than 70%)and AM fungi significantly enhanced plants’tolerance to salt stress of varying magnitude.Higher activity of antioxidant enzymes and augmented levels of proline and other osmoregulators were observed in AM plants.The content of MDA in CK was higher than that in the inoculations with the stress of 100,200,and 250 mM.All indices except soluble protein content and MDA content were significantly correlated with AM fungal colonization indices.The analysis for different AM fungal effects showed that the mixtures and R.irregularis worked even better than C.etunicatum.These results will provide theoretical support for the exploration and screening of salt-tolerant AM fungi species and also for the application of AM-ornamental plants in saline-alkali urban greening.
基金the Project of Marine and Fishery Technology Innovation of Shandong(No.2017 HYCX007).
文摘The construction of artificial reefs has unparallelly developed for a few decades in China.Artificial reefs can be used to manage and conserve commercially exploited fish and crustacea.However,their suitability as ecological niche is poorly characterized.Therefore,in this study,we detected the seasonal variation of community biodiversity and the corresponding driving environmental factors.We also explored the relationships between dominant species and environmental factors to identify appropriate ecological niche areas.Different statistical analysis methods were used to assess species distribution within an artificial reef area in Xixiakou during nine sampling events in four seasons between 2017 and 2018.Non-metric multidimensional scaling(NMDS)and cluster analysis results indicated that the components of community can be divided into two clusters.Complexity of community,which is exhibited by species number,biodiversity,and catch per unit effort(CPUE),was significantly higher in summer than in other seasons.Generalized additive model(GAMs)results revealed the significant effects of temperature and chlorophyll a on the community structure.Sebastes schlegelii,Hexagrammos otakii,Conger myriaster and Charybdis japonica were the dominant species in four seasons.GAMs results indicated that temperature,dissolved oxygen(DO),pH and chlorophyll a affect the CPUE of dominant species significantly.The distinct suitable ecological niche for each dominant species was found in this study.For example,Charybdis japonica preferred to live in the area with 20.7–22.1℃,dissolved oxygen 7.07–7.15 mg L−1 and salinity 31.8–31.9.The results of this study are beneficial to resource conservation and fishery management.
基金The work was supported by the Fundamental Research Funds for the Central University(No.2572020DY11).
文摘Pine wilt disease caused by pine wood nema-todes is a deadly disease of the genus Pinus requiring strong quarantine measures.Since its discovery,it has been widely distributed throughout the world.China is one of the coun-tries with a severe rate of infections due to its abundant pine resources.In this study,nematode-trapping fungi were collected from pine trees in Ninghai City,Zhejiang Prov-ince,which is the key area of pine wilt control in Febru-ary,May,September,October and November.The results showed that nematode-trapping fungi of pine are abundant,especially the number and species detected in each month and are quite different;species of fungi in July,Septem-ber and November were more numerous and had higher separation rates.The dominant species in November was Arthrobotrys oligospora followed by Arthrobotrys cladodes;July and September it was A.cladodes.In each part of the tree,A.cladodes was the most widely distributed with a high separation rate.Therefore,it is the dominant fungal species in the area.Arboreal Bursaphelenchus xylophilus-trapping fungi are dependent on pine wood nematodes,and none were isolated from healthy pine trees.More arboreal B.xylophilus-trapping fungi were found under the bark than in the xylem.There is a close relationship between arboreal B.xylophilus-trapping fungi and pine wood nematodes.How to make use of these resources to reduce the damage of pine wood nematode fusarium is the focus of future research.
基金Sponsored by the National High Technology Research and Development Program of China(863Program)(Grant No.2008ZX07211-007)
文摘In this paper,the characteristics of the water quality in Yellow River estuary reservoirs were surveyed and the progress of the eutrophication was investigated by observing the behavior of nitrogen and phosphorus.The results showed that the concentration of dissolved inorganic nitrogen and total nitrogen was very high in all the reservoirs,and the level of nitrogen was eutrophic state.According to Vollenweider's type model for phosphorus load,the total phosphorus was close to permissible load in Guangnan and Xinan reservoirs.But sometimes,the total phosphorus exceeded an excessive load in Gengjing reservoir.In Yellow River estuary reservoirs,Cyanobacteria,and Diatom phytoplankton were observed mainly,and the cyanobacteria was a the dominant species in summer.
基金This work a contribution to Youth Foundation of Natural Science Foundation of Henan Province(212300410153)The Young Talents Promotion Project of Henan Province(2020HYTP037)+1 种基金Science and Technology Project of Henan Provincial Department of Natural Resources(No.2021-178-9)Basic scientific research expenses of Henan Province(2021JB02014).
文摘The spatial-temporal variation of understory light availability has important influences on species diversity and community assembly.However,the distribution characteristics and influencing factors of understory light availability have not been fully elucidated,especially in temperate deciduous,broad-leaved forests.In this study,the understory light availability was monitored monthly(May–October)in a temperate deciduous,broad-leaved forest in Henan Province,China.Differences in the light availability among different months and habitat types were statistically analyzed using Kruskal–Wallis method,respectively.Partial least squares path modeling(PLS-PM)was used to explore the direct and/or indirect effects of stand structure,dominant species and topographic factors on the light environment.Results showed that there were differences in light environments among the four habitat types and during the studied six months.The PLS-PM results showed that the stand structure and the dominant species were negatively correlated with the light environment,and the path coefficient values were−0.089(P=0.042)and−0.130(P=0.004),respectively.Our result indicated that the understory light availability exhibit a distinct spatial and temporal heterogeneity in temperate deciduous,broad-leaved forest of north China.The characteristics of woody plant community,especially the abundance of one of the dominant plant species,were the important factors affecting the understory light availability.
基金Supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2012BAD18B01&2012BAD18B02)Science and Technology Planning Project of Shenzhen(JSGG20141015154342147&JCYJ20160331141759795)
文摘Seasonal variations and causes for these were elaborated for fishery resources in Shenzhen sea area,to provide scientific basis for sustainable utilization and management of fishery resources in typical fisheries of South China Sea coasts. Based on the data of fishery resources collected through trawl surveys in Egong Bay fisheries area,Shenzhen,from August( autumn) and December( winter) of 2012 to March(spring) and May(summer) of 2013,seasonal variation of nekton species composition,stock density,dominant species composition,size spectra and biodiversity were studied. Results showed that there were 113 species of nekton in Shenzhen sea area,which belonged to 78 genus,50 families,14 orders and 3 classes. The number of species was the largest in summer(61 species) and smallest in autumn(53 species). In spring and winter,there was 56 species. The stock density and individual density of nekton were the minimum in summer(5950. 20 kg/km2 and 356. 45 ind/km2,respectively),whereas the percentage of fish stock density and individual density were the highest in summer(51. 99%and 42. 19%). The seasonal variations of size spectra indicated that fishing intensity was the highest in autumn,and was the lowest in summer. Additionally,biodiversity index presented significant seasonal variations,including Shannon-Wiener diversity index( H '),Margalef richness index( D') and Pielou evenness index( J'),with the same trend as summer > spring > autumn > winter. In conclusion,there are clear seasonal variations in the nekton species,biomass and structure in Egong Bay fisheries area in Shenzhen. Due to the difference in fishing intensity in different seasons( low intensity in summer and high intensity in autumn),community structure and function in summer are more stable than that in autumn and winter. Particularly,with the increase in the fishing intensity in autumn,k selection species will be replaced by r selection species.
基金Supported by China Agriculture Research System of MOF and MARA(CARS-170303)Yunling Industry and Technology Leading Talent Training Program(2018LJRC56)Special Fund for the Construction of Modern Agricultural Industry Technology System in Yunnan Province.
文摘[Objectives]This study was conducted to identify the pathogen species and dominant species of sugarcane pokkah boeng in main varieties in Yunnan sugarcane areas,so as to promote the healthy and sustainable development of sugarcane industry.[Methods]Specific primers Fv-F3/Fv-R3 and Fp-F4/Fp-R4 were designed based on the ribosomal DNA non-internal transcribed spacer(rDNA-ITS)gene sequences of Fusarium verticillioides and Fusarium proliferarum,the main pathogens of sugarcane pokkah boeng,and 117 typical sugarcane pokkah boeng samples collected from main varieties in different sugarcane areas of Yunnan Province were detected and analyzed by PCR.[Results]Among the 117 sugarcane pokkah boeng samples,112 samples were detected with F.verticillioides with a positive detection rate of 95.7%;103 samples were detected with F.proliferarum with a positive detection rate of 88%;103 samples were infected by F.verticillioides+F.proliferarum,and the compound infection rate was 88%;and the two pathogens were not detected in 5 samples,which might be sugarcane pokkah boeng caused by other species.PCR amplification products of 23 F.verticillioides positive samples and 19 F.proliferarum positive samples from different sugarcane varieties in different sugarcane areas were sequenced.The BLAST alignment results showed that the sequences of the 23 amplification products of F.verticillioides shared 99.45%-100.00%homology with F.verticillioides(GenBank accession number:KU508286),and the sequences of the 19 amplification products of F.proliferarum shared 99.26%-100.00%homology with the sequence of F.proliferarum(GenBank accession number:MK252904).Part of the F.verticillioids and 11 F.proliferarum sequences were selected to construct a phylogenetic tree,and the phylogenetic analysis showed that they belonged to the F.verticillioids group and F.proliferarum group,respectively.The results showed that F.verticillioides and F.proliferarum were the main pathogens causing sugarcane pokkah boeng of the main sugarcane varieties in Yunnan,and there was a common phenomenon of compound infection.F.verticillioides was the dominant species in Pu er,Lincang,Honghe and Yuxi sugarcane areas,but the detection rate of F.proliferarum was also high,and there were other species.In the future,the discovery of resistant germplasm resources and breeding of resistant varieties should be carried out aiming at these two pathogens of sugarcane pokkah boeng.[Conclusions]The study provides technical support for rapid identification of sugarcane pokkah boeng pathogens,and scientific basis for breeding resistant varieties and scientific disease prevention and control.
基金Supported by China Agriculture Research System of MOF and MARA(CARS-170303)“Yunling Industry and Technology Leading Talent”Training Program"Prevention and Control of Sugarcane Pests"(2018LJRC56)Special Fund for the Construction of Modern Agricultural Industry Technology System in Yunnan Province(YNGZTX-4-92)。
文摘[Objectives]This study was conducted to determine the pathogen species and dominant species of sugarcane pokkah boeng in the sugarcane areas of Yunnan in the low-latitude plateau,so as to provide a basis for the pathogenic mechanism,disease resistance breeding and scientific prevention and control of pokkah boeng.[Methods]With 14 pokkah boeng samples collected from different sugarcane areas in Yunnan as materials,pokkah boeng-specific detection primers FvF4/Fv-R4 and Fp-F3/Fp-R3 were designed based on ribosomal DNA non-transcribed spacer(rDNA-ITS)sequences,respectively,and used to perform PCR on Fusarium verticillioides and F.proliferatum.[Results]In 12 of the 14 pokkah boeng samples,two species of pokkah boeng pathogens were detected,and there was a phenomenon of composite infection.Seven composite infection samples were selected for sequence alignment and phylogenetic analysis.The sequences of F.verticillioides(Gen Bank accession number:MZ126549-MZ126555)and F.proliferatum(Gen Bank accession number:MZ102259-MZ102265)from seven composite infection samples shared 98.6%-100%and 100%with F.verticillioides strain 20(Gen Bank accession number:KU508286)and F.proliferatum Dehong strain(GenBank accession number:KJ629482)published in Gen Bank,respectively.The phylogenetic tree showed that the pathogens of sugarcane pokkah boeng in Yunnan were mainly divided into the F.verticillioides group and F.proliferatum group.In the F.verticillioides group,except for ROC 25(Lancang,Yunnan)and Funong10-1405(Maitreya,Yunnan)which were on an independent branch,the remaining five composite infection samples were grouped with F.verticillioides strains from different geographical origins,and were closely related to F.oxysporum Guangxi strain.All strains of F.proliferatum from different geographic origins were clustered into another group.[Conclusions]This study provides a scientific basis for disease resistance breeding and disease prevention and control of sugarcane pokkah boeng.
基金This work was supported by the National Natural Science Foundation of China(Grant No.41730641)Project from Ministry of Science and Technology of China(Basic Research project:2014FY110600 and 13-5 Project:2016YFA0600802).
文摘Forests in Northeast China in the Greater and Lesser Khingan Mountains(GKM and LKM)account for nearly 1/3 of the total state-owned forests in the country.Regional and historical comparisons of forest plants and macrofungi will favor biological conservation,forest management and economic development.A total of 1067 sampling plots were surveyed on forest composition and structure,with a macrofungi survey at Liangshui and Huzhong Nature Reserves in the center of two regions.Regional and historical differences of these parameters were analyzed with a redundancy ordination of their complex associations.There were 61-76 families,189-196 genera,and 369-384 species,which was only 1/3 of the historical records.The same dominant species were larch and birch with Korean pine(a climax species)less as expected from past surveys in the LKM.Shrub and herb species were different in the two regions,as expected from historical records.There was 10-50%lower species diversity(except for herb evenness),but 1.8-to 4-time higher macrofungi diversity in the GKM.Compared with the LKM,both tree heights and macrofungi density were higher.Nevertheless,current heights averaging 10 m are half of historical records(>20 m in the 1960s).Edible macrofungi were the highest proportion in both regions,about twice that of other fungal groups,hav-ing important roles in the local economy.A major factor explaining plant diversity variations in both regions was herb cover,followed by shrubs in the GKM and herb-dominant species in the LKM.Factors responsible for macrofungi variations were tree density and shrub height.Vaccinium vitis-idaea and Larix gmelinii in the GKM but tree size and diversity were important factors in the LKM.Our findings highlighted large spatial and historical differences between the GKM and LKM in plant-macrofungal composition,forest structure,and their complex associations,which will favor precise conservation and management of forest resources in two region in the future.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31030000)National Natural Science Foundation of China (32170210, 31770231, and 32011530072)K.C. Wong Education Foundation (GJTD2020-05)。
文摘The dominant species of a biome can be regarded as its genuine indicator.Evergreen broadleaved forests(EBLFs) in subtropical East Asia harbor high levels of species biodiversity and endemism and are vital to regional carbon storage and cycling.However,the historical assembly of this unique biome is still controversial.Fagaceae is the most essential family in East Asian subtropical EBLFs and its dominant species are vital for the existence of this biome.Here,we used the dominant Fagaceae species to shed light on the dynamic process of East Asian subtropical EBLFs overtime.Our results indicate high precipitation in summer and low temperature in winter are the most influential climatic factors for the distribution of East Asian subtropical EBLFs.Modern East Asian subtropical EBLFs did not begin to appear until 23 Ma,subsequently experienced a longlasting development in the Miocene and markedly deteriorated at about 4 Ma,driven jointly by orogenesis and paleoclimate.We also document that there is a lag time between when one clade invaded the region and when its members become dominant species within the region.This study may improve our ability to predict and mitigate the threats to biodiversity of East Asian subtropical EBLFs and points to a new path for future studies involving multidisciplinary methods to explore the assembly of regional biomes.
文摘Aims Decades of empirical work have demonstrated how dominant plant species and nitrogen fertilization can influence the structure and function of plant communities.More recent studies have examined the interplay between these factors,but few such studies use an explicit trait-based framework.In this study,we use an explicit trait-based approach to identify potential mechanisms for community-level responses and to test ecological niche theory.Methods We experimentally manipulated plant communities(control,−dom-inant species,−random biomass)and nitrogen(N)inputs(control,+organic N,+inorganic N)in a fully factorial design.We predicted that traits related to plants’ability to take up different forms of soil N would differ between dominant and subordinate species,resulting in interactive effects of dominant species loss and N fertilization on plant community structure and function.The study took place in a montane meadow in the Rocky Mountains,Colorado,USA.Important Findings After four years,the plant community in removal plots converged toward a species composition whose leaf and root functional traits resembled those of the previously removed dominant species.Ecosystem productivity generally increased with N addition:soil carbon efflux was~50%greater when either form of N was added,while inorganic N addition increased aboveground biomass pro-duction by~60%relative to controls.The increase in production was mediated by increased average height,leaf mass:area ratio and leaf dry matter content in plant communities to which we added inorganic N.Contrary to our predictions,there were no interactive effects of N fertilization and dominant species loss on plant com-munity structure or ecosystem function.The plant community com-position in this study exhibited resistance to soil N addition and,given the functional convergence we observed,was resilient to spe-cies loss.Together,our results indicate that the ability of species to compensate functionally for species loss confers resilience and maintains diversity in montane meadow communities.
基金supported by the National Natural Science Foundation of China(32060284,31870441)the Natural Science Foundation of Inner Mongolia,China(2019JQ04)+2 种基金the Central Government Guides the Local Science and Technology Development Foundation(2020ZY0027)the National Science Foundation of the United States(DEB-1856318,CBET-1833988)the Natural Science Foundation of Hebei Province(C2022201042)。
文摘Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought.Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought,whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought.The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species,and the community biomass resistance and recovery were also greatly driven by the stability of grasses.Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability.Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects.Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.
