To investigate the life cycle of marine sulfate aerosols, chemicophysical characteristics of marine aerosolswere measured during five cruises in the Pacific Ocean. Dimethyl sulfide concentrations in seawater and in th...To investigate the life cycle of marine sulfate aerosols, chemicophysical characteristics of marine aerosolswere measured during five cruises in the Pacific Ocean. Dimethyl sulfide concentrations in seawater and in the air were also measured. The geographic variation of sulfate-aerosol concentrations was studied in relation to biogenic and anthropogenic sources,transport with air trajectories, and chemical transformations in the atmosphere. The highest concentrations were found near Asian and American ports, indicating anthropogenic pollution is the major sulfate aerosols source. Higher concentrations were observed in the upwelling regions than in the oligotrophic areas. Along the coastal regions, both mass and number concentrations of sulfate aerosols depended on wind direction and wind speed, and land-breeze and sea-breeze oscillations; no clear diurnal variation was detected. In pelagic areas, along the equator, the concentrations of small sulfate particles showed a maximum in the afternoon and the minimum at night , indicating photo-oxidation as an important process for gas-to-particle conversion. Higher sulfate-aerosol concentrations were observed in spring than in autumn and higher concentrations were found during the La Nina anomaly than during the El Nino anomaly. Biogenic source of sulfate aerosols has an important role in the remote ocean. Case studies of sulfate-aerosol distributions are discussed.展开更多
In order to characterize the genetic relationship of the geographic populations of Sitobion avenae (Hemiptera: Aphididae) in China, a 588 bp region of the mitochondrial cytochrome oxidase subunit I (mtDNA-COI) ge...In order to characterize the genetic relationship of the geographic populations of Sitobion avenae (Hemiptera: Aphididae) in China, a 588 bp region of the mitochondrial cytochrome oxidase subunit I (mtDNA-COI) gene was sequenced and analyzed among the different geographic populations. 269 individuals were collected from 17 localities in different wheat-growing areas in China that covered most of the range reported for this species. Within the sequence among these geographic populations, 15 polymorphic sites defined 16 distinct haplotypes, ranging in sequence divergence from 0.2% (one nucleotide) to 1.7% (10 nucleotides). Of the 15 variable sites, 12 were transitional substitutions, 2 were transversional substitutions and 1 was transitional and transversional substitution. Phylogenetic analysis showed that all haplotypes were highly interconnected with each other, in absence of phylogeographic structing. Each of 8 haplotypes was found only at one locality, and the other haplotypes were the widespread distributed in the different localities. The higher genetic diversity was found in the northern China populations than that in the southern China populations. The low genetic differentiation (FST=-0.06945-0.69857) and high migration rate (Nm=0.21575-infinite) of Chinese populations suggest that dispersal over long distance is a major factor in the demography of S. avenae.展开更多
Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical va...Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible.展开更多
Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed...Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences be- tween fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in ele- vation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis.展开更多
In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters o...In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters of Phrynocephalus przewalskii (Agamidae) in different populations within the same phylogenetic clade were compared in this study. Female SVL, clutch size, egg volume and clutch volume varied significantly among populations. With increase in latitude, clutch size increased, while egg size decreased. Relatively fewer but larger eggs were produced with increasing of population density. Food availability had positive effects on clutch size, but no effect on egg size. Our result indicated that latitude, food availability and population density may be the proximate factors affecting the reproductive parameters ofP. przewalskii.展开更多
On the basis of the results from the geographic provenance test of nine years old /arix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best...On the basis of the results from the geographic provenance test of nine years old /arix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best provenance of torix oIgensis was carried out. The main results are as follows: 1. The different provenances of Larix olgensis have rich and wide genetic variation, and exist a linear correlation with latitude and longitude in collection area. General trends are enumerated below: Provenances at lower latitude and more west longitude have lighter thousand seed weight. short growth period, higher increment, wide branches, rich leaves and crown as well as worst adaptabi llity. It is a dual-way variation along with two directions of latitude and longitude, and also embodies a change gradually in climate condition from south to north. The temperat ures in seed production site, especially the mean temperature in January and≥10℃ accumulated temperature, are important factors that produce geographic variation for larix olgensis. 2. The variation of different provenances in periodic biological phenomena and growth rhythm trends are that: ① both of the provenances from Changbai Mt. (Ⅲ) and Dashitou(Ⅳ) at low latitude belong to the centralized growth type, and have shout growth period, the difference between these two provenances is that the provenance from Changbai Mt. grows well in all time, Dashitou provennce is well only in later period; ②the provenance from Baidao Mt. (Ⅱ) at middle latitude belongs to even growth type and has longer grpwth period, this provenance has higher increment in early and later periods relatively; ③ Xiaobeihu provenance at high latitude is a growth type among Ⅱ Ⅲ and Ⅳ provenances and has a general growth period, the provenance grows better in middle time and worse in later time. 3. The best provenance in Liangshui Natural Reserve and its meighbourhood is Dashitou Procenance. which growth in height. diameter and volume has exceeded 16. 28%, 46. 27%, 30. 58%, 78. 20, 82. 00% as well as 392. 00% by comparison with the mean value of the contrast and the worst provenance respectively, The result from the height growth of three, five. seven and nine years old Larix olgensis by using the method of order correlation analysis demonstrates that it is possible to make early selection of the provenance. Meanwhile. data from juvenile and mature of larix olgensis plantation also prove the reliability of the early selection. 4. The provenance heritabilities of nine years old larix olgensis in Liangshui Natural Reserve are follows:The heritability of the height growth (h2)is 0. 79; The heritability of the diameter breast height (h2) is 0. 791; The geretic gain is 24. 5%and 40. 36% respectively.展开更多
Environmental conditions greatly affect the growth of rice. To investigate the geographic differences in yield formation of single-season high-yielding hybrid rice in southern China, experiments were conducted in 2017...Environmental conditions greatly affect the growth of rice. To investigate the geographic differences in yield formation of single-season high-yielding hybrid rice in southern China, experiments were conducted in 2017 and 2018 in the upper and middle–lower reaches of the Yangtze River with 10–30 main locally planted high-yielding hybrid cultivars used as materials. Compared with rice planted in the middle–lower reaches of the Yangtze River, rice planted in the upper reaches has a longer tillering duration, higher accumulated temperature(≥10℃) during tillering period, but lower accumulated temperature and solar radiation from initial booting to maturity. Yield traits comparison between the upper and the middle–lower reaches of Yangtze River showed that the former had 48.1% more panicles per unit area while the latter had 46.4% more grains per panicle;the rice yield in the former was positively correlated with the seed setting rate and the dry matter accumulation before heading, while the latter was positively correlated with grains per panicle and dry matter accumulation from booting to maturity. Comparison of the same variety Tianyouhuazhan planted in different regions showed there was a significant positive correlation between panicle number and the duration of and accumulated temperature during the tillering period(r=0.982^(**), r=0.993^(**), respectively), and between grains per panicle and accumulated solar radiation during booting period(r=0.952~*). In the upper reaches of the Yangtze River, more than 90% of cultivars with an yield of greater than 11 t ha^(–1) had an effective panicle number of 250–340 m^(–2), and there was a significant negative correlation between seed setting rate and grains per panicle;therefore, the high-yielding rice production in these regions with a long effective tillering period(>40 d) should choose varieties with moderate grains per panicle, adopt crop managements such as good fertilizer and water measures during vegetative growth period to ensure a certain number of effective panicles, and to increase the dry matter accumulation before heading. While in regions with a short effective tillering period(<20 d) but good sunshine conditions during the reproductive growth period, such as the middle–lower reaches of the Yangtze River, high-yielding rice production should choose cultivars with large panicles, adopt good water and fertilizer managements during the reproductive growth period to ensure the formation of large panicles and the increase of dry matter accumulation after heading.展开更多
Geographic variation of morphology is an important topic of evolutionary biology,and research on geographic variation can provide insights on the formation,evolution,and adaptation of species and subspecies.The verteb...Geographic variation of morphology is an important topic of evolutionary biology,and research on geographic variation can provide insights on the formation,evolution,and adaptation of species and subspecies.The vertebrate skull is a developmentally and functionally complex morphological structure with multiple functions,that is susceptible to vary according to selection pressure.In this study,geographic variations in skull morphology of Batrachuperus karlschmidti from four different geographic populations(Shade,Gexi,Shangluokema,and Xinduqiao)were examined via geometric morphometrics.No significant differences were found among these populations with regard to skull size;however,significant variation was found in skull shape.The most notable shape changes are the relative sizes and positions of the frontal,maxilla,pterygoid,and vomer.Skull shape changes were not related to allometry.However,due to limitation of sample populations and size,the results of this study need to be further verified by more sample populations and individuals in the future.The results of this study contribute to our knowledge about these aspects of morphological variability in this species as well as in hynobiid salamanders.展开更多
Sexual dimorphism(SD) and geographic variation(GV) are widespread in snakes. Protobothrops mucrosquamatus(Cantor 1839) is one of the most common Asian venomous snakes with a wide geographical distribution. We ex...Sexual dimorphism(SD) and geographic variation(GV) are widespread in snakes. Protobothrops mucrosquamatus(Cantor 1839) is one of the most common Asian venomous snakes with a wide geographical distribution. We examined SD and GV patterns for this species by using multivariate statistical analyses of external morphological characters scored from specimens from the China's Mainland. The result displayed that SD was significant in several external characters in P. mucrosquamatus, and the male P. mucrosquamatus formed two distinct clusters(Hainan Island and China's Mainland), but the females did not. Based on our present work and the other data, we concluded that no significantly intraspecific differentiation is present within this species.展开更多
This paper summarizes the result from the provenance test of eight years old Pinus sylvestris var. mongolica in Liangshui Natural Rcserve comprehensivcly. The main contents include:(1) the geographic variation of the ...This paper summarizes the result from the provenance test of eight years old Pinus sylvestris var. mongolica in Liangshui Natural Rcserve comprehensivcly. The main contents include:(1) the geographic variation of the growth characters of Pinus sylvestris var.mongolica.tends to negative change gradually at latitude and has obvious climatic nature, (2) no significant difference exists in the morphological adaptability and resistant characteristics and so on; (3)on the basis of the geographic variation study on the growth characteristics, the provcnances of Pinus sylvestris var. mongolica were classificd into two geographic populations and two subpopulations as follows:the northern population of the Daxing'an Mountain (Ⅰ) and the southern population of the Daxing'an Mountain as wcll as the Xiaoxinglan Mountain (Ⅱ),which includcs Honghuarii subpopulation and Kalunshan subpopulation (Ⅱ-2). (4) the height growth rhythm was analyzed according to the divided population and subpopuIation; (5) the best provcnance was selected for the Liangshui Natural Rescrve and its neighborhood accord ing to the results from SSR test of the growth characteristics (the breast height diameter and height of eight year old trces), the possibility of the carly provcnance sclection was also verified by the method of order correlation analysis on the height growth of three. five, scvcn and eight years old provenances.展开更多
Based on the main characteristics of growth, phenology and resistance at both seedling stage (one year old) and sampling stage (seven years old) of Dahurian larch (Larix gmelinii (Rupr.) Rupr.) from seventeen provenan...Based on the main characteristics of growth, phenology and resistance at both seedling stage (one year old) and sampling stage (seven years old) of Dahurian larch (Larix gmelinii (Rupr.) Rupr.) from seventeen provenances in China ranging from 47 ° 10' to 52 ° 25' N and 119 ° 57' to 130 ° 25' E, the rules and patterns of infraspecific geographic variation have been studied by using variance analysis, correlation analysis, partial correlation analysis and regression analysis. The best provenance for local site and its neighborhood was selected according to the growth characteristics of seven years provenance test on Liangshui Experimental Forest Farm of Northeast Forestry University.展开更多
Identifying the sex pheromone systems of local pest populations facilitates their management,especially for moth species that show significant geographic variation in sex pheromone communication.We investigated the ph...Identifying the sex pheromone systems of local pest populations facilitates their management,especially for moth species that show significant geographic variation in sex pheromone communication.We investigated the pheromone production and behavioral responses of the Asian corn borer(Ostrinia furnacalis Guenée;ACB)in Xinjiang,China.The ACB produces three compounds:(Z)-12-tetradecenyl acetate(Z12-14:Ac)and(E)-12-tetradecenyl acetate(E12-14:Ac)which are two sex pheromone compounds,and n-tetradecyl acetate(14:Ac)which has variable roles in mediating behavioral responses.The ratios of these three compounds produced in female gland are geographically distinct among different populations.Quantitative analysis of pheromone production showed that the proportions of Z12-14:Ac in the E/Z isomers(i.e.,Z and E12-14:Ac)and the proportions of 14:Ac in the ternary blend respectively averaged 60.46%(SD=5.26)and 25.00%(SD=7.37),with their probabilities normally or near-normally distributed.Trapping experiments in a cornfield indicated that deploying the E/Z isomers and the three compounds in rubber septa close to their gland ratios yielded the most captured males,while other ratios that deviated from the gland ratios showed reduced field captures.The ternary blend was significantly more attractive to males than the E/Z isomers in the field,indicating a functional role of 14:Ac as the third pheromone component used by the local population.Additionally,the dose-response test demonstrated that the application of the three compounds at dosages between 200 and 350μg attracted significantly more males compared to other dosages.Therefore,the characterization of this local ACB pheromone system provides additional information about its geographic variation and serves as a basis for optimizing the pheromone-mediated control of this pest in Xinjiang.展开更多
Dialects are a specific form of geographic variation of birdsong with relatively sharp boundaries between distinct song characteristics,which provide opportunities for focused studies of processes underlying the emerg...Dialects are a specific form of geographic variation of birdsong with relatively sharp boundaries between distinct song characteristics,which provide opportunities for focused studies of processes underlying the emergence of spatial patterns in vocalization.Several songbird species that exhibit dialects became models for such research,and for some of them large-scale datasets were assembled that included recordings provided by the public.Among them,the Yellowhammer(Emberiza citrinella,Emberizidae) is particularly prominent,as it has been recently a subject of dedicated citizen science projects focusing on its dialect distribution.The most successful,in terms of public participation as well as the number and density of obtained recordings,was the Dialects of Czech Yellowhammers(DCY) project,which assembled detailed data at the whole-country level.A mosaic of almost all common song variants known across Europe was observed in Czechia,but the results indicated that some of the traditionally recognized Yellowhammer dialects may not represent geographically clustered song variants,at least not in Central Europe.We quantitatively analysed variation(frequency and temporal characteristics and modulation) of the terminal song element in three dialects defined by arbitrary frequency thresholds in DCY.Multivariate analyses indicated that pooling these to two distinct groups reflects the variation in the songs,as well as their spatial distribution,better than retaining the current classification to three dialects or their finer splitting to even more categories.We provide simple measures that may be used for classification of these Yellowhammer song variants in Central Europe.However,we warn from indiscriminate transposing of results from one region to another,as that may lead to substantial biases.Future studies of birdsong variation will benefit from big data assembled by citizen scientists,but to maximise their usefulness for further dialect research,careful delineation of dialect boundaries is essential.展开更多
The song systems of oscine passerines(songbirds)are complex and diverse.Because songs are used for both mate attraction and territory defense and are therefore important signals for survival and reproduction,comprehen...The song systems of oscine passerines(songbirds)are complex and diverse.Because songs are used for both mate attraction and territory defense and are therefore important signals for survival and reproduction,comprehensive knowledge of within and among species song structure and distribution is informative for understanding the evolution of song repertoires and vocal behaviour.In this study,we explored variation in the song structure of the Ovenbird(Seiurus aurocapilla),a widespread warbler(Family Parulidae)found in North American forests.We analyzed recordings from the 2021 breeding season to assess song type variation at a local(n=158 birds;Sault Ste.Marie,ON)and breeding range scale(n=512 birds;eBird).We characterized the local song types and tested whether Ovenbirds share song types with their neighbors more often than expected by chance.We then characterized song types of Ovenbirds across the breeding range to determine whether any geographic pattern of song clustering exists(i.e.,macro-dialects).We found 10 distinct song types and some evidence for song type clustering at the local study site(i.e.,song neighborhoods).We found 7 of those 10 song types throughout the breeding range and identified an additional 24 types that were not recorded in our local population.We found no evidence for song dialects across the Ovenbird breeding range.This study contributes to our understanding of Ovenbird song while simultaneously adding to our understanding of geographic structuring of warbler repertoires.Our work contributes to delineating a more comprehensive understanding of factors affecting dialect development for this diverse group of songbirds.展开更多
Objective: The aim is to study the trends in ventricular septal defect (VSD) mortality in children in Kazakhstan.Methods: The retrospective study was done for the period 2011–2020. Descriptive and analytical methods ...Objective: The aim is to study the trends in ventricular septal defect (VSD) mortality in children in Kazakhstan.Methods: The retrospective study was done for the period 2011–2020. Descriptive and analytical methods of epidemiologywere applied. The universally acknowledged methodology used in sanitary statistics is used to calculatethe extensive, crude, and age-specific mortality rates. Results: Kazakhstan is thought to be seeing an increase inmortality from VSDs in children. As a result, this study for the years 2011 to 2020 was conducted to retrospectivelyassess data from the central registration of the Bureau of National Statistics that was available throughoutthe nation. Age-standardized mortality data were obtained and compared between age categories. It was shownthat 507 children died from this condition throughout the time period under study. The average annual standardizedmortality rate was 1.88 per 100,000 population and tended to decrease over time. The peak of mortality wasnoted at the age of up to 1 year, namely the neonatal period. Cartogram mortality rates were calculated usingstandardized indicators. Additionally, age-sex variations were taken into account when performing all calculations.Conclusion: In recent years, the death rate from VSD has declined from 1.5 to 0.6 per 100,000 people, withthe trend remaining constant (T = 1.4%, R^(2) = 0.5825). The analysis of mortality trends related to VSD is crucial inboth theoretical and practical aspects, as it enables early detection and treatment of VSDs. The findings of thisstudy will be valuable to public health authorities in developing a strategy to treat VSDs effectively.展开更多
Objective To study the prevalence of different types of neural tube defects (NTDs) in Luliang Prefecture, Shanxi province, where the prevalence of NTDs is unusually high and the correlation between NTDs prevalence a...Objective To study the prevalence of different types of neural tube defects (NTDs) in Luliang Prefecture, Shanxi province, where the prevalence of NTDs is unusually high and the correlation between NTDs prevalence and patterns. Methods A surveillance population-based birth defects was performed in Luliang Prefecture, Shanxi province. Results The results of our study showed that the prevalence of NTDs was 2-fold higher in Luliang Prefecture than in other areas of Shanxi province. Unusual patterns of NTDs were found, however, multiple NTDs were relatively common in Luliang Prefecture, accounting for over 13% of all NTDs cases in China. Conclusion The prevalence of NTDs is associated with its patterns.展开更多
Background:Previous studies have shown inconsistent or even contradictory results for some risk factors associated with HIV infection among drug users,and these may be partially explained by geographical variations.Me...Background:Previous studies have shown inconsistent or even contradictory results for some risk factors associated with HIV infection among drug users,and these may be partially explained by geographical variations.Methods:Data were collected from 11 methadone clinics in the Liangshan Yi Autonomous Prefecture from 2004 to 2012.A non-spatial logistical regression model and a geographically weighted logistic regression model were fitted to analyze the association between HIV infection and specific factors at the individual level.Results:This study enrolled 6,458 patients.The prevalence of HIV infection was 25.1%.The non-spatial model indicated that being divorced was positively associated with HIV infection.The spatial model also showed that being divorced was positively associated with HIV infection,but only for 49.4%of individuals residing in some northern counties.The non-spatial model suggested that service sector work was negatively associated with HIV infection.However,the spatial model indicated that service work was associated with HIV infection,but only for 23.0%of patients living in some western counties.The non-spatial model did not show that being married was associated with HIV infection in our study field,but the spatial model indicated that being married was negatively associated with HIV infection for 12.0%of individuals living in some western counties.For other factors,the non-spatial and spatial models showed similar results.Conclusion:The spatial model may be useful for improving understanding of geographical heterogeneity in the relationship between HIV infection and individual factors.Spatial heterogeneity may be useful for tailoring intervention strategies for local regions,which can consequently result in a more efficient allocation of limited resources toward the control of HIV transmission.展开更多
The data of provenance trial on Juglans mandshurica young tree were investigated and studied from different provenance. Analysis methods of variance and correlation analysis were used to analyze these data. The follow...The data of provenance trial on Juglans mandshurica young tree were investigated and studied from different provenance. Analysis methods of variance and correlation analysis were used to analyze these data. The following conclusions were obtainedf (1) The difference of growth characters of Juglans mandshurica is relatively significant among provenances, (2) The result of first trial has indicated that Julans mandshurica growth trend expresses two-way gradual change trend with different longitude and latitude, but the second trial has no obvious gradual change trend. Height of Juglans mandshurica is negatively correlated with elevation; (3) The provenance of Shulan. Mao'ershan and Baishishan were selected as superior provenance of afforestational seeds for Mao'ershan and its brink region.展开更多
As one of the top four commercially important species in China,yellow croaker(Larimichthys polyactis)with two geographic subpopulations,has undergone profound changes during the last several decades.It is widely compr...As one of the top four commercially important species in China,yellow croaker(Larimichthys polyactis)with two geographic subpopulations,has undergone profound changes during the last several decades.It is widely comprehended that understanding its population dynamics is critically important for sustainable management of this valuable fishery in China.The only two existing population dynamics models assessed the population of yellow croaker using short time-series data,without considering geographical variations.In this study,Bayesian models with and without hierarchical subpopulation structure were developed to explore the spatial heterogeneity of the population dynamics of yellow croaker from 1968 to 2015.Alternative hypotheses were constructed to test potential temporal patterns in yellow croaker’s population dynamics.Substantial variations in population dynamics characteristics among space and time were found through this study.The population growth rate was revealed to increase since the late 1980s,and the catchability increased more than twice from 1981 to 2015.The East China Sea’s subpopulation witnesses faster growth,but suffers from higher fishing pressure than that in the Bohai Sea and Yellow Sea.The global population and two subpopulations all have high risks of overfishing and being overfished according to the MSY-based reference points in recent years.More conservative management strategies with subpopulation considerations are imperative for the fishery management of yellow croaker in China.The methodology developed in this study could also be applied to the stock assessment and fishery management of other species,especially for those species with large spatial heterogeneity data.展开更多
Background:Red-winged Blackbirds(Agelaius phoeniceus),hereafter red-wings,are much less frequently parasitized by Brown-headed Cowbirds(Molothrus ater)in eastern North America than in central North America and had not...Background:Red-winged Blackbirds(Agelaius phoeniceus),hereafter red-wings,are much less frequently parasitized by Brown-headed Cowbirds(Molothrus ater)in eastern North America than in central North America and had not been recorded as hosts in our study area in southeastern Pennsylvania.Although hosts of Old World cuckoos(Cuculidae)often show geographic variation in egg rejection behavior,cowbird hosts typically exhibit uniform responses of all acceptance or all rejection of cowbird eggs.Thus,geographic variation in cowbird parasitism frequencies might reflect a different behavioral response to parasitism by hosts where only some populations reject parasitism.In this study,we tested whether egg rejection behavior may explain the lack of parasitism observed in our eastern red-wing population,which may provide insight into low parasitism levels across eastern North America.Methods:We parasitized red-wing nests with model cowbird eggs to determine their response to parasitism.Nests were tested across three nest stages and compared to control nests with no manipulations.Because rejection differed significantly by stage,we compared responses separately for each nest stage.We also monitored other songbird nests to identify parasitism frequencies on all potential hosts.Results:Red-wings showed significantly more rejections during the building stage,but not for the laying and incubation stages.Rejections during nest building involved mostly egg burials,which likely represent a continuation of the nest building process rather than true rejection of the cowbird egg.Excluding these responses,red-wings rejected 15%of cowbird eggs,which is similar to rejection levels from other studies and populations.The overall parasitism frequency on 11 species surveyed in our study area was only 7.4%.Conclusions:Egg rejection behavior does not explain the lack of parasitism on red-wings in our eastern population.Alternatively,we suggest that cowbird preference for other hosts and the low abundance of cowbirds in the east might explain the lack of parasitism.Future research should also explore cowbird and host density and the makeup of the host community to explain the low levels of parasitism on red-wings across eastern North America because egg rejection alone is unlikely to explain this broad geographic trend.展开更多
文摘To investigate the life cycle of marine sulfate aerosols, chemicophysical characteristics of marine aerosolswere measured during five cruises in the Pacific Ocean. Dimethyl sulfide concentrations in seawater and in the air were also measured. The geographic variation of sulfate-aerosol concentrations was studied in relation to biogenic and anthropogenic sources,transport with air trajectories, and chemical transformations in the atmosphere. The highest concentrations were found near Asian and American ports, indicating anthropogenic pollution is the major sulfate aerosols source. Higher concentrations were observed in the upwelling regions than in the oligotrophic areas. Along the coastal regions, both mass and number concentrations of sulfate aerosols depended on wind direction and wind speed, and land-breeze and sea-breeze oscillations; no clear diurnal variation was detected. In pelagic areas, along the equator, the concentrations of small sulfate particles showed a maximum in the afternoon and the minimum at night , indicating photo-oxidation as an important process for gas-to-particle conversion. Higher sulfate-aerosol concentrations were observed in spring than in autumn and higher concentrations were found during the La Nina anomaly than during the El Nino anomaly. Biogenic source of sulfate aerosols has an important role in the remote ocean. Case studies of sulfate-aerosol distributions are discussed.
基金supported by the National Basic Research Program of China (973 Program, 2006CB102004)the National S&T Major Project of China (2009ZX08012-007B)+1 种基金the National Natural Science Foundation of China (30971920)the Inter-University Targeted Project between Belgium and China (PIC SHANDONG)
文摘In order to characterize the genetic relationship of the geographic populations of Sitobion avenae (Hemiptera: Aphididae) in China, a 588 bp region of the mitochondrial cytochrome oxidase subunit I (mtDNA-COI) gene was sequenced and analyzed among the different geographic populations. 269 individuals were collected from 17 localities in different wheat-growing areas in China that covered most of the range reported for this species. Within the sequence among these geographic populations, 15 polymorphic sites defined 16 distinct haplotypes, ranging in sequence divergence from 0.2% (one nucleotide) to 1.7% (10 nucleotides). Of the 15 variable sites, 12 were transitional substitutions, 2 were transversional substitutions and 1 was transitional and transversional substitution. Phylogenetic analysis showed that all haplotypes were highly interconnected with each other, in absence of phylogeographic structing. Each of 8 haplotypes was found only at one locality, and the other haplotypes were the widespread distributed in the different localities. The higher genetic diversity was found in the northern China populations than that in the southern China populations. The low genetic differentiation (FST=-0.06945-0.69857) and high migration rate (Nm=0.21575-infinite) of Chinese populations suggest that dispersal over long distance is a major factor in the demography of S. avenae.
基金Under the auspices of Special Foundation for State Major Basic Research Program of China(No.2013FY111800,2013FY111100-02)
文摘Biological invasion poses a huge threat to ecological security.Spartina alterniflora was introduced into China in 1979,and its arrival corresponded with negative effects on native ecosystems.To explore geographical variation of its expansion rate in coastal China,we selected 43 S.alterniflora sites from Tianjin Coastal New Area to Beihai.The area expansion rate,expansion rate paralleling and vertical to the shoreline were analysed based on Landsat images and field survey in 2015.Simple Ocean Data Assimilation(SODA)and climate data were collected to statistically analyse the influential factors of expansion rate.Results showed that significant difference of S.alterniflora area expansion rate among different latitude zones(P<0.01),increasing from 6.08%at southern(21°N–23°N)to 19.87% in Bohai Bay(37°N–39°N)along latitude gradient.There was a significant difference in expansion rate vertical to shoreline in different latitude zones(P<0.01)with the largest occurring in Bohai Bay(256m/yr,37°N–39°N),and showed an decreasing tendency gradually from north to south.No significant difference and latitudinal clines in expansion rate paralleling to shoreline were observed.Expansion rate had significant negative correlation with mean seawater temperature,the lowest seawater temperature,current zonal velocity and meridional velocity and presented a reducing trend as these biotic factors increased;however,they were not significantly correlated with the highest seawater temperature and mean seawater salinity.We identified significant correlations between expansion rate and annual mean temperature,the lowest temperature in January and annual precipitation,but there was little correlation with annual diurnal difference in temperature and the highest temperature in July.The rapid expansion rate in high-latitude China demonstrated a higher risk of potential invasion in the north;dynamic monitoring and control management should be established as soon as possible.
文摘Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences be- tween fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in ele- vation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis.
文摘In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters of Phrynocephalus przewalskii (Agamidae) in different populations within the same phylogenetic clade were compared in this study. Female SVL, clutch size, egg volume and clutch volume varied significantly among populations. With increase in latitude, clutch size increased, while egg size decreased. Relatively fewer but larger eggs were produced with increasing of population density. Food availability had positive effects on clutch size, but no effect on egg size. Our result indicated that latitude, food availability and population density may be the proximate factors affecting the reproductive parameters ofP. przewalskii.
文摘On the basis of the results from the geographic provenance test of nine years old /arix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best provenance of torix oIgensis was carried out. The main results are as follows: 1. The different provenances of Larix olgensis have rich and wide genetic variation, and exist a linear correlation with latitude and longitude in collection area. General trends are enumerated below: Provenances at lower latitude and more west longitude have lighter thousand seed weight. short growth period, higher increment, wide branches, rich leaves and crown as well as worst adaptabi llity. It is a dual-way variation along with two directions of latitude and longitude, and also embodies a change gradually in climate condition from south to north. The temperat ures in seed production site, especially the mean temperature in January and≥10℃ accumulated temperature, are important factors that produce geographic variation for larix olgensis. 2. The variation of different provenances in periodic biological phenomena and growth rhythm trends are that: ① both of the provenances from Changbai Mt. (Ⅲ) and Dashitou(Ⅳ) at low latitude belong to the centralized growth type, and have shout growth period, the difference between these two provenances is that the provenance from Changbai Mt. grows well in all time, Dashitou provennce is well only in later period; ②the provenance from Baidao Mt. (Ⅱ) at middle latitude belongs to even growth type and has longer grpwth period, this provenance has higher increment in early and later periods relatively; ③ Xiaobeihu provenance at high latitude is a growth type among Ⅱ Ⅲ and Ⅳ provenances and has a general growth period, the provenance grows better in middle time and worse in later time. 3. The best provenance in Liangshui Natural Reserve and its meighbourhood is Dashitou Procenance. which growth in height. diameter and volume has exceeded 16. 28%, 46. 27%, 30. 58%, 78. 20, 82. 00% as well as 392. 00% by comparison with the mean value of the contrast and the worst provenance respectively, The result from the height growth of three, five. seven and nine years old Larix olgensis by using the method of order correlation analysis demonstrates that it is possible to make early selection of the provenance. Meanwhile. data from juvenile and mature of larix olgensis plantation also prove the reliability of the early selection. 4. The provenance heritabilities of nine years old larix olgensis in Liangshui Natural Reserve are follows:The heritability of the height growth (h2)is 0. 79; The heritability of the diameter breast height (h2) is 0. 791; The geretic gain is 24. 5%and 40. 36% respectively.
基金supported by grants from the National Key Research and Development Program of China(2016 YFD0300108)the National Natural Science Foundation of China(31671630)the earmarked fund for China Agriculture Research System(CARS-01-04A)。
文摘Environmental conditions greatly affect the growth of rice. To investigate the geographic differences in yield formation of single-season high-yielding hybrid rice in southern China, experiments were conducted in 2017 and 2018 in the upper and middle–lower reaches of the Yangtze River with 10–30 main locally planted high-yielding hybrid cultivars used as materials. Compared with rice planted in the middle–lower reaches of the Yangtze River, rice planted in the upper reaches has a longer tillering duration, higher accumulated temperature(≥10℃) during tillering period, but lower accumulated temperature and solar radiation from initial booting to maturity. Yield traits comparison between the upper and the middle–lower reaches of Yangtze River showed that the former had 48.1% more panicles per unit area while the latter had 46.4% more grains per panicle;the rice yield in the former was positively correlated with the seed setting rate and the dry matter accumulation before heading, while the latter was positively correlated with grains per panicle and dry matter accumulation from booting to maturity. Comparison of the same variety Tianyouhuazhan planted in different regions showed there was a significant positive correlation between panicle number and the duration of and accumulated temperature during the tillering period(r=0.982^(**), r=0.993^(**), respectively), and between grains per panicle and accumulated solar radiation during booting period(r=0.952~*). In the upper reaches of the Yangtze River, more than 90% of cultivars with an yield of greater than 11 t ha^(–1) had an effective panicle number of 250–340 m^(–2), and there was a significant negative correlation between seed setting rate and grains per panicle;therefore, the high-yielding rice production in these regions with a long effective tillering period(>40 d) should choose varieties with moderate grains per panicle, adopt crop managements such as good fertilizer and water measures during vegetative growth period to ensure a certain number of effective panicles, and to increase the dry matter accumulation before heading. While in regions with a short effective tillering period(<20 d) but good sunshine conditions during the reproductive growth period, such as the middle–lower reaches of the Yangtze River, high-yielding rice production should choose cultivars with large panicles, adopt good water and fertilizer managements during the reproductive growth period to ensure the formation of large panicles and the increase of dry matter accumulation after heading.
基金supported by the National Natural Science Foundation of China(31471971)。
文摘Geographic variation of morphology is an important topic of evolutionary biology,and research on geographic variation can provide insights on the formation,evolution,and adaptation of species and subspecies.The vertebrate skull is a developmentally and functionally complex morphological structure with multiple functions,that is susceptible to vary according to selection pressure.In this study,geographic variations in skull morphology of Batrachuperus karlschmidti from four different geographic populations(Shade,Gexi,Shangluokema,and Xinduqiao)were examined via geometric morphometrics.No significant differences were found among these populations with regard to skull size;however,significant variation was found in skull shape.The most notable shape changes are the relative sizes and positions of the frontal,maxilla,pterygoid,and vomer.Skull shape changes were not related to allometry.However,due to limitation of sample populations and size,the results of this study need to be further verified by more sample populations and individuals in the future.The results of this study contribute to our knowledge about these aspects of morphological variability in this species as well as in hynobiid salamanders.
基金funded by the National Natural Science Foundation of China (NSFC31372152)the Scientific Research Fund of Sichuan Provincial Education Department (13TD0027) to Peng Guo
文摘Sexual dimorphism(SD) and geographic variation(GV) are widespread in snakes. Protobothrops mucrosquamatus(Cantor 1839) is one of the most common Asian venomous snakes with a wide geographical distribution. We examined SD and GV patterns for this species by using multivariate statistical analyses of external morphological characters scored from specimens from the China's Mainland. The result displayed that SD was significant in several external characters in P. mucrosquamatus, and the male P. mucrosquamatus formed two distinct clusters(Hainan Island and China's Mainland), but the females did not. Based on our present work and the other data, we concluded that no significantly intraspecific differentiation is present within this species.
文摘This paper summarizes the result from the provenance test of eight years old Pinus sylvestris var. mongolica in Liangshui Natural Rcserve comprehensivcly. The main contents include:(1) the geographic variation of the growth characters of Pinus sylvestris var.mongolica.tends to negative change gradually at latitude and has obvious climatic nature, (2) no significant difference exists in the morphological adaptability and resistant characteristics and so on; (3)on the basis of the geographic variation study on the growth characteristics, the provcnances of Pinus sylvestris var. mongolica were classificd into two geographic populations and two subpopulations as follows:the northern population of the Daxing'an Mountain (Ⅰ) and the southern population of the Daxing'an Mountain as wcll as the Xiaoxinglan Mountain (Ⅱ),which includcs Honghuarii subpopulation and Kalunshan subpopulation (Ⅱ-2). (4) the height growth rhythm was analyzed according to the divided population and subpopuIation; (5) the best provcnance was selected for the Liangshui Natural Rescrve and its neighborhood accord ing to the results from SSR test of the growth characteristics (the breast height diameter and height of eight year old trces), the possibility of the carly provcnance sclection was also verified by the method of order correlation analysis on the height growth of three. five, scvcn and eight years old provenances.
文摘Based on the main characteristics of growth, phenology and resistance at both seedling stage (one year old) and sampling stage (seven years old) of Dahurian larch (Larix gmelinii (Rupr.) Rupr.) from seventeen provenances in China ranging from 47 ° 10' to 52 ° 25' N and 119 ° 57' to 130 ° 25' E, the rules and patterns of infraspecific geographic variation have been studied by using variance analysis, correlation analysis, partial correlation analysis and regression analysis. The best provenance for local site and its neighborhood was selected according to the growth characteristics of seven years provenance test on Liangshui Experimental Forest Farm of Northeast Forestry University.
基金supported by grants from the Key R&D Program of the Xinjiang Autonomous Region,China(2021b02002-2)the National Natural Science Foundation of China(31960538)。
文摘Identifying the sex pheromone systems of local pest populations facilitates their management,especially for moth species that show significant geographic variation in sex pheromone communication.We investigated the pheromone production and behavioral responses of the Asian corn borer(Ostrinia furnacalis Guenée;ACB)in Xinjiang,China.The ACB produces three compounds:(Z)-12-tetradecenyl acetate(Z12-14:Ac)and(E)-12-tetradecenyl acetate(E12-14:Ac)which are two sex pheromone compounds,and n-tetradecyl acetate(14:Ac)which has variable roles in mediating behavioral responses.The ratios of these three compounds produced in female gland are geographically distinct among different populations.Quantitative analysis of pheromone production showed that the proportions of Z12-14:Ac in the E/Z isomers(i.e.,Z and E12-14:Ac)and the proportions of 14:Ac in the ternary blend respectively averaged 60.46%(SD=5.26)and 25.00%(SD=7.37),with their probabilities normally or near-normally distributed.Trapping experiments in a cornfield indicated that deploying the E/Z isomers and the three compounds in rubber septa close to their gland ratios yielded the most captured males,while other ratios that deviated from the gland ratios showed reduced field captures.The ternary blend was significantly more attractive to males than the E/Z isomers in the field,indicating a functional role of 14:Ac as the third pheromone component used by the local population.Additionally,the dose-response test demonstrated that the application of the three compounds at dosages between 200 and 350μg attracted significantly more males compared to other dosages.Therefore,the characterization of this local ACB pheromone system provides additional information about its geographic variation and serves as a basis for optimizing the pheromone-mediated control of this pest in Xinjiang.
基金funded by the Charles University Grant Agency (project number 312213)
文摘Dialects are a specific form of geographic variation of birdsong with relatively sharp boundaries between distinct song characteristics,which provide opportunities for focused studies of processes underlying the emergence of spatial patterns in vocalization.Several songbird species that exhibit dialects became models for such research,and for some of them large-scale datasets were assembled that included recordings provided by the public.Among them,the Yellowhammer(Emberiza citrinella,Emberizidae) is particularly prominent,as it has been recently a subject of dedicated citizen science projects focusing on its dialect distribution.The most successful,in terms of public participation as well as the number and density of obtained recordings,was the Dialects of Czech Yellowhammers(DCY) project,which assembled detailed data at the whole-country level.A mosaic of almost all common song variants known across Europe was observed in Czechia,but the results indicated that some of the traditionally recognized Yellowhammer dialects may not represent geographically clustered song variants,at least not in Central Europe.We quantitatively analysed variation(frequency and temporal characteristics and modulation) of the terminal song element in three dialects defined by arbitrary frequency thresholds in DCY.Multivariate analyses indicated that pooling these to two distinct groups reflects the variation in the songs,as well as their spatial distribution,better than retaining the current classification to three dialects or their finer splitting to even more categories.We provide simple measures that may be used for classification of these Yellowhammer song variants in Central Europe.However,we warn from indiscriminate transposing of results from one region to another,as that may lead to substantial biases.Future studies of birdsong variation will benefit from big data assembled by citizen scientists,but to maximise their usefulness for further dialect research,careful delineation of dialect boundaries is essential.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Canadian Foundation for Innovation(CFI)+1 种基金Ontario Ministry of Research and Innovation(OMRI)Northern Ontario Heritage Fund Corporation(NOHFC)。
文摘The song systems of oscine passerines(songbirds)are complex and diverse.Because songs are used for both mate attraction and territory defense and are therefore important signals for survival and reproduction,comprehensive knowledge of within and among species song structure and distribution is informative for understanding the evolution of song repertoires and vocal behaviour.In this study,we explored variation in the song structure of the Ovenbird(Seiurus aurocapilla),a widespread warbler(Family Parulidae)found in North American forests.We analyzed recordings from the 2021 breeding season to assess song type variation at a local(n=158 birds;Sault Ste.Marie,ON)and breeding range scale(n=512 birds;eBird).We characterized the local song types and tested whether Ovenbirds share song types with their neighbors more often than expected by chance.We then characterized song types of Ovenbirds across the breeding range to determine whether any geographic pattern of song clustering exists(i.e.,macro-dialects).We found 10 distinct song types and some evidence for song type clustering at the local study site(i.e.,song neighborhoods).We found 7 of those 10 song types throughout the breeding range and identified an additional 24 types that were not recorded in our local population.We found no evidence for song dialects across the Ovenbird breeding range.This study contributes to our understanding of Ovenbird song while simultaneously adding to our understanding of geographic structuring of warbler repertoires.Our work contributes to delineating a more comprehensive understanding of factors affecting dialect development for this diverse group of songbirds.
文摘Objective: The aim is to study the trends in ventricular septal defect (VSD) mortality in children in Kazakhstan.Methods: The retrospective study was done for the period 2011–2020. Descriptive and analytical methods of epidemiologywere applied. The universally acknowledged methodology used in sanitary statistics is used to calculatethe extensive, crude, and age-specific mortality rates. Results: Kazakhstan is thought to be seeing an increase inmortality from VSDs in children. As a result, this study for the years 2011 to 2020 was conducted to retrospectivelyassess data from the central registration of the Bureau of National Statistics that was available throughoutthe nation. Age-standardized mortality data were obtained and compared between age categories. It was shownthat 507 children died from this condition throughout the time period under study. The average annual standardizedmortality rate was 1.88 per 100,000 population and tended to decrease over time. The peak of mortality wasnoted at the age of up to 1 year, namely the neonatal period. Cartogram mortality rates were calculated usingstandardized indicators. Additionally, age-sex variations were taken into account when performing all calculations.Conclusion: In recent years, the death rate from VSD has declined from 1.5 to 0.6 per 100,000 people, withthe trend remaining constant (T = 1.4%, R^(2) = 0.5825). The analysis of mortality trends related to VSD is crucial inboth theoretical and practical aspects, as it enables early detection and treatment of VSDs. The findings of thisstudy will be valuable to public health authorities in developing a strategy to treat VSDs effectively.
基金supported by the Major State Basic Research and Development Program of China "973 Program" (No.2007CB511901)special for National Postdoctoral fund (200801016)+2 种基金National Health Baby Promotion Program (No. FP2000NO13)Education Ministry Key Program (No. 02185)National Yangzi Scholar Program, 211 and 985 Projects of Peking University (No. 20020903)
文摘Objective To study the prevalence of different types of neural tube defects (NTDs) in Luliang Prefecture, Shanxi province, where the prevalence of NTDs is unusually high and the correlation between NTDs prevalence and patterns. Methods A surveillance population-based birth defects was performed in Luliang Prefecture, Shanxi province. Results The results of our study showed that the prevalence of NTDs was 2-fold higher in Luliang Prefecture than in other areas of Shanxi province. Unusual patterns of NTDs were found, however, multiple NTDs were relatively common in Luliang Prefecture, accounting for over 13% of all NTDs cases in China. Conclusion The prevalence of NTDs is associated with its patterns.
文摘Background:Previous studies have shown inconsistent or even contradictory results for some risk factors associated with HIV infection among drug users,and these may be partially explained by geographical variations.Methods:Data were collected from 11 methadone clinics in the Liangshan Yi Autonomous Prefecture from 2004 to 2012.A non-spatial logistical regression model and a geographically weighted logistic regression model were fitted to analyze the association between HIV infection and specific factors at the individual level.Results:This study enrolled 6,458 patients.The prevalence of HIV infection was 25.1%.The non-spatial model indicated that being divorced was positively associated with HIV infection.The spatial model also showed that being divorced was positively associated with HIV infection,but only for 49.4%of individuals residing in some northern counties.The non-spatial model suggested that service sector work was negatively associated with HIV infection.However,the spatial model indicated that service work was associated with HIV infection,but only for 23.0%of patients living in some western counties.The non-spatial model did not show that being married was associated with HIV infection in our study field,but the spatial model indicated that being married was negatively associated with HIV infection for 12.0%of individuals living in some western counties.For other factors,the non-spatial and spatial models showed similar results.Conclusion:The spatial model may be useful for improving understanding of geographical heterogeneity in the relationship between HIV infection and individual factors.Spatial heterogeneity may be useful for tailoring intervention strategies for local regions,which can consequently result in a more efficient allocation of limited resources toward the control of HIV transmission.
文摘The data of provenance trial on Juglans mandshurica young tree were investigated and studied from different provenance. Analysis methods of variance and correlation analysis were used to analyze these data. The following conclusions were obtainedf (1) The difference of growth characters of Juglans mandshurica is relatively significant among provenances, (2) The result of first trial has indicated that Julans mandshurica growth trend expresses two-way gradual change trend with different longitude and latitude, but the second trial has no obvious gradual change trend. Height of Juglans mandshurica is negatively correlated with elevation; (3) The provenance of Shulan. Mao'ershan and Baishishan were selected as superior provenance of afforestational seeds for Mao'ershan and its brink region.
基金Foundation item:The National Key R&D Program of China under contract No.2017YFE0104400the National Natural Science Foundation of China under contract No.31772852the Fundamental Research Funds for the Central Universities under contract Nos 201512002 and 201562030.
文摘As one of the top four commercially important species in China,yellow croaker(Larimichthys polyactis)with two geographic subpopulations,has undergone profound changes during the last several decades.It is widely comprehended that understanding its population dynamics is critically important for sustainable management of this valuable fishery in China.The only two existing population dynamics models assessed the population of yellow croaker using short time-series data,without considering geographical variations.In this study,Bayesian models with and without hierarchical subpopulation structure were developed to explore the spatial heterogeneity of the population dynamics of yellow croaker from 1968 to 2015.Alternative hypotheses were constructed to test potential temporal patterns in yellow croaker’s population dynamics.Substantial variations in population dynamics characteristics among space and time were found through this study.The population growth rate was revealed to increase since the late 1980s,and the catchability increased more than twice from 1981 to 2015.The East China Sea’s subpopulation witnesses faster growth,but suffers from higher fishing pressure than that in the Bohai Sea and Yellow Sea.The global population and two subpopulations all have high risks of overfishing and being overfished according to the MSY-based reference points in recent years.More conservative management strategies with subpopulation considerations are imperative for the fishery management of yellow croaker in China.The methodology developed in this study could also be applied to the stock assessment and fishery management of other species,especially for those species with large spatial heterogeneity data.
基金provided by a BEARS Grant and a Neag Undergraduate Research Grant from Kutztown University
文摘Background:Red-winged Blackbirds(Agelaius phoeniceus),hereafter red-wings,are much less frequently parasitized by Brown-headed Cowbirds(Molothrus ater)in eastern North America than in central North America and had not been recorded as hosts in our study area in southeastern Pennsylvania.Although hosts of Old World cuckoos(Cuculidae)often show geographic variation in egg rejection behavior,cowbird hosts typically exhibit uniform responses of all acceptance or all rejection of cowbird eggs.Thus,geographic variation in cowbird parasitism frequencies might reflect a different behavioral response to parasitism by hosts where only some populations reject parasitism.In this study,we tested whether egg rejection behavior may explain the lack of parasitism observed in our eastern red-wing population,which may provide insight into low parasitism levels across eastern North America.Methods:We parasitized red-wing nests with model cowbird eggs to determine their response to parasitism.Nests were tested across three nest stages and compared to control nests with no manipulations.Because rejection differed significantly by stage,we compared responses separately for each nest stage.We also monitored other songbird nests to identify parasitism frequencies on all potential hosts.Results:Red-wings showed significantly more rejections during the building stage,but not for the laying and incubation stages.Rejections during nest building involved mostly egg burials,which likely represent a continuation of the nest building process rather than true rejection of the cowbird egg.Excluding these responses,red-wings rejected 15%of cowbird eggs,which is similar to rejection levels from other studies and populations.The overall parasitism frequency on 11 species surveyed in our study area was only 7.4%.Conclusions:Egg rejection behavior does not explain the lack of parasitism on red-wings in our eastern population.Alternatively,we suggest that cowbird preference for other hosts and the low abundance of cowbirds in the east might explain the lack of parasitism.Future research should also explore cowbird and host density and the makeup of the host community to explain the low levels of parasitism on red-wings across eastern North America because egg rejection alone is unlikely to explain this broad geographic trend.