The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource uti...The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource utilization, including partitioning, in degraded wetlands has become a hot issue in ecological studies of wintering waterbirds. In order to have an insight into the habitat utilization and resource partitioning between a Hooded Crane(Grus monacha) population and the guild of three goose species, i.e., Anser fabalis, A. albifrons and A. erythropus wintering in lake wetlands, we carried out a study at Shengjin Lake National Nature Reserve from November 2011 to April 2012. We surveyed the Hooded Cranes and goose guild foraging in various habitats during the wintering periods with a combined method of fixed route searching and fixed site observations. Resource partitioning was studied by means of calculating habitat utilization rates and the width and overlap of spatial niches. The results showed that the habitat utilization rate and the width of spatial niches of the Hooded Crane population and goose guild shifted with the season. The habitat utilization rates of the cranes in grasslands were high at all three wintering stages. The habitat utilization rates were 0.454, 0.435 and 0.959 respectively for the Hooded Cranes and 0.627, 0.491 and 0.616 for the goose guild. This suggests that the overlap in grasslands was higher between cranes and goose guild. Most habitats were accessible at the middle stage, so the width of the spatial niche of the cranes(1.099) and goose guild(1.133) both reached their peak at this stage. The greatest niche overlap was 0.914 for these two groups at the late stage, followed by 0.906 at the middle stage and the smallest was 0.854 at the early stage. Ecological response to the changes in habitats of wintering waterbirds was clearly shown in the dynamic variations of the niche of both the Hooded Cranes and the three goose species. Coexistence among waterbirds was achieved by regulation of niche width to reduce niche overlap and relieve interspecific resource partitioning.展开更多
[Objective] This study aimed to explore the biological habits of Scirothrips dorsalis Hood and methods for controlling this pest. [Method] From 2009 to 2011, the biological habits of Scirothrips dorsalis Hood and the ...[Objective] This study aimed to explore the biological habits of Scirothrips dorsalis Hood and methods for controlling this pest. [Method] From 2009 to 2011, the biological habits of Scirothrips dorsalis Hood and the regularity of its occurrence on mangoes were investigated at the experimental base of the Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences and Shuanghongqiao Mango Orchard in Baoshan, Yunnan Province. In addition, a field trial on the effects of four medicaments on controlling this pest was also conducted. [Result] The result showed that Scirothrips dorsalis Hood completed 10-12 genera- tions per year in Baoshan area, and the peak period of its incidence was from February to April. The results of the pest control testing showed that at 0.05 level, there were significant differences of effect on pest controlling among the treatments I, II and IV, and the treatment III showed significant differences of controlling effect with the treatment IV, while no significant differences with either the treatment I or the treatment II; at 0.01 level, there was no significant difference among the treat- ments I, II and III, while all the three treatments showed significant differences with treatment IV. [Conclusion] This study revealed that the occurrence and the severity of Scirothrips dorsalis Hood on mangoes in Baoshan, Yunnan Province. In addition, pesticides with certain efficacy on controlling Scirothrips dorsalis Hood were screened, which provides more options for fruit growers to control this pest on mangoes.展开更多
Background:Food abundance and availability affect flock patterns of foraging birds.Cost and risk tradeoffs are especially critical for flocks of wintering waterbirds foraging in lake wetlands.Waterbirds losing suitabl...Background:Food abundance and availability affect flock patterns of foraging birds.Cost and risk tradeoffs are especially critical for flocks of wintering waterbirds foraging in lake wetlands.Waterbirds losing suitable habitats face insufficient food supplies and high levels of disturbance,affecting their foraging activities.Our objective was to study the effects of food abundance and disturbances on flock size and the structure of Hooded Crane flocks wintering at Shengjin Lake and,as well,to understand the response of wintering waterbirds to habitat degradation for future management decisions and protection of the population.Methods:We investigated food abundance,disturbances and flock foraging activities of the wintering Hooded Crane in several foraging habitats of Shengjin Lake from November 2013 to April 2014.Flock size and structure were observed by scan sampling.Data on food abundance and disturbances were collected by sampling.Flock size and structure were compared among three wintering stages.The relationship between food resources,disturbances and flock size were illustrated using a generalized linear model.Results:In the early and middle wintering periods,the Hooded Crane used paddy fields as its major foraging habitat,where the number of foraging birds and flocks were the highest.During the late period,the cranes took to meadows as their major foraging habitat.The variation among foraging flock was mainly embodied in the size of the flocks,while the age composition of these flocks did not change perceptibly.Family flocks were notably different from flock groups in size and age composition.The results of a generalized linear model showed that the food abundance had a marked effect on foraging flock size and age composition,while disturbances had a significant effect only on flock size.From our analysis,it appeared that the combined effect of the two variables was significant on the size of the foraging flock,but had less impact on age composition.Conclusions:Food abundance and disturbances affected the flock size of the Hooded Crane.With abundant food and high disturbances,flock sizes increased owing to cooperation in foraging.To avoid competition and maximize foraging benefits,flock size reduces with an abundance of food but low disturbance.By trading off risks and costs,the cranes showed flexible flock distributions and a variety of foraging strategies to maximize benefits and to improve their fitness.展开更多
Abstract Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam tur- bine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal d...Abstract Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam tur- bine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal design of its structure without consideration of the wet steam condensing flow and the exhaust hood coupled with the front and rear parts. To better understand the aerodynamic performance influenced by the tilt angle of flow guide inside a diffuser, taking a 600 MW steam turbine as an example, a numerical simulator CFX is adopted to solve compressible three-dimensional （3D） Reynolds time-aver- aged N-S equations and standard k-e turbulence model. And the exhaust hood flow field influenced by different tilt angles of flow guide is investigated with consideration of the wet steam condensing flow and the exhaust hood coupled with the last stage blades and the condenser throat. The result shows that the total pressure loss coefficient and the static pressure recovery coefficient of exhaust hood change regularly and monotonously with the gradual increase of tilt angle of flow guide. When the tilt angle of flow guide is within the range of 30~ to 40~, the static pressure recovery coefficient is in the range of 15.27% to 17.03% and the total pressure loss coefficient drops to approximately 51%, the aerodynamic performance of exhaust hood is significantly improved. And the effectiveenthalpy drop in steam turbine increases by 0.228% to 0.274%. It is feasible to obtain a reasonable title angle of flow guide by the method of coupling the last stage and the condenser throat to exhaust hood in combination of the wet steam model, which provides a practical guidance to flow guide transformation and optimal design in exhaust hood.展开更多
Background:The ideal habitat use of waterbirds can be considered to be fixed,but current habitat use depends on environmental conditions,especially those of food characteristics,considered crucial to their use of habi...Background:The ideal habitat use of waterbirds can be considered to be fixed,but current habitat use depends on environmental conditions,especially those of food characteristics,considered crucial to their use of habitats.Understanding how waterbirds respond to variation in food availability at degraded wetland sites and change their habitat use patterns over spatial and temporal scales should direct future conservation planning.The objectives of this study were to identify these spatial-temporal foraging habitat use patterns of Hooded Cranes(Grus monacha)and their relationship with food characteristics in the severely degraded wetlands of the Shengjin and Caizi lakes along with the Yangtze River floodplain.Methods:We investigated the changes in food characteristics,relative abundance and density of Hooded Cranes in various habitat types across three winter periods from November 2012 to April 2013.We examined the effect of these winter periods and habitat types on the pattern of use by the cranes and explored the relationship between these patterns and food characteristics using linear regression.Results:The food characteristics and habitat use clearly changed over spatial-temporal scales.In the early and mid-winter periods,the most abundant,accessible and frequented food resources were found in paddy fields,while in the late period the more abundant food were available in meadows,which then replaced the paddy fields.There were fewer effects of winter periods,habitat types and their interactions on habitat use patterns except for the effect of habitat types on the relative abundance,determined as a function of food abundance,but independent of food depth and sediment permeability.Conclusions:In response to the degradation and loss of lake wetlands,the cranes shifted their habitat use patterns by making tradeoffs between food abundance and accessibility over spatial-temporal scales that facilitated their survival in the mosaic of these lake wetlands.展开更多
Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temp...Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temporal-spatial patterns of foraging activities.It is of considerable importance to investigate the effect of these fluctuations on food availability for wintering Hooded Cranes and their foraging response to these changes.Understanding their behavior patterns is beneficial in protecting the wintering crane population and restoring their wintering habitats.Methods:A field survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014.Habitat variables,as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during five stages of water level fluctuation were collected.Based on this data we analyzed the relationship of foraging behavior relative to water level fluctuations and habitat types.Results:The foraging habitats used by Hooded Cranes varied at the different water level stages.As the water level decreased,the use of meadows and mudflats increased.When the water dropped to its lowest level,the use by the Hooded Crane in the mudflats reached a peak.There were statistically significant differences in time budget in the three types of habitats over the five stages of the water level.In the mudflats,the foraging behavior and maintenance behavior varied significantly with the water level,while the alert behavior showed little variation.Analysis of a generalized linear model showed that the five water level stages and three habitat types had a significant effect on foraging behavior,while the combined effect of these two variables was significant on the foraging time budget and the length of foraging activity of the Hooded Crane.Conclusions:With the decrease in the water level,the use of mudflats by Hooded Cranes increased correspondingly.Food availability in different habitats was affected by changes in the water level.The Hooded Crane adjusted its foraging patterns and made full use of the three available types of habitat in order to acquire enough food in response to fluctuations in the water level.展开更多
Background: Parasites have adverse effects on the life and survival of many migratory waterbirds, especially birds on the endangered species list. Hooded Cranes are large migratory colonial waterbirds wintering in wet...Background: Parasites have adverse effects on the life and survival of many migratory waterbirds, especially birds on the endangered species list. Hooded Cranes are large migratory colonial waterbirds wintering in wetlands,which are prone to parasite infection, thus monitoring the diversity of parasites is important for sound wetland management and protection of this species.Methods: From November 2012 to April 2013, we collected 821 fresh faecal samples from the three lakes(Poyang,Caizi and Shengjin Lake) in the lower and middle Yangtze River floodplain, and detected with saturated brine floating and centrifugal sedimentation methods. Parasite eggs were quantified with a modified Mc Master's counting method.Results: In this study, 11 species of parasites were discovered, i.e., two coccidium(Eimeria gruis, E. reichenowi), five nematodes(Capillaria sp., Strongyloides sp., Ascaridia sp., Trichostrongylus sp., Ancylostomatidae), three trematodes(Echinostoma sp., Echinochasmus sp., Fasciolopsis sp.) and one cestode(Hymenolepis sp.). About 57.7% of the faecal samples showed parasitic infection. All species of parasites were found at the three sites except Hymenolepis which was not found at Poyang Lake. While most samples were affected by only one or two species of parasites, infection by Eimeria spp. was the most common(53.1%). From One-Way ANOVA analysis of the three lakes, parasite species richness index(p = 0.656), diversity index(p = 0.598) and evenness index(p = 0.612) showed no significant difference. According to the statistical analysis of our data, there were no significant difference in parasite species richness index(p = 0.678) and evenness index(p = 0.238) between wintering periods, but a strong difference in diversity index(p < 0.05).Conclusions: Our study suggests that in the wintering Hooded Crane populations, parasite diversity is more sensitive to changes in the overwintering periods than to locations. This also indicates that with the limitations of migration distance, the parasites may not form the differentiation in Hooded Crane populations of the three lakes.展开更多
A novel hood structure has been designed for the dust control system in the foundry in order to improve the working environment. A composite strategy has been applied for comparative analysis of the optimal venting vo...A novel hood structure has been designed for the dust control system in the foundry in order to improve the working environment. A composite strategy has been applied for comparative analysis of the optimal venting volume and the airflow distribution between the conventional hood and the novel one in this study. A Computational Fluid Dynamic (CFD) method is used to simulate the airflow fields and dust-polluted air moving paths. The CFD results show that a two-outlet hood, with one outlet located on the left of the hood, is better for improving dust-polluted air than the hood with one outlet only. It can be concluded that the number of the outlets as well as their location on the hood has a significant influence on the air flow pattern in the hood. The optimal venting volume is also a major consideration that is discussed in the study. The venting volume should be designed by considering both the effective level of air flow velocity around the dust source and the energy saving. The optimal airflow distribution may reduce the turbulence in the hood system.展开更多
A new local exhaust ventilation hood is presented. First, the test system inlaboratory room is established. Secondly a mathematical model is developed in terms of the stokesstream function, and the governing equation ...A new local exhaust ventilation hood is presented. First, the test system inlaboratory room is established. Secondly a mathematical model is developed in terms of the stokesstream function, and the governing equation is solved using finite-difference techniques. Theinjection flow of the exhaust hood is treated as a boundary condition of the main flow. Experimentsresults well agree with the solution of theoretical prediction. The model can, therefore, be used todesign this kind of Aaberg hood. Thirdly the important parameters affecting the performance ofAaberg exhaust hood are taken into account. In the mean time the connection of these parameters isdeduced by multivariate linear regression based on the experimental results. The work is usefulwhether in designing this kind of local ventilation Aaberg exhaust hood or in predicting the hood'swork performance.展开更多
Both the Siberian Crane(Leucogeranus leucogeranus) and Hooded Crane(Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies.To document the current size...Both the Siberian Crane(Leucogeranus leucogeranus) and Hooded Crane(Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies.To document the current size of their respective populations and characterize their groups,between October 2012 and April 2013 we undertook fieldwork at four nature reserve areas within the Poyang Lake wetlands.We divided Poyanghu National Nature Reserve(PYH) into the Wucheng(PWC) and Hengfeng areas(PHF),because each are each located in different counties.Our fieldwork showed that the Siberian Crane occurred mainly in PYH(364 in the PHF,158 in the PWC) and the Nanjishan Wetland National Nature Reserve(NJS,with 200 individuals).The Hooded Crane was mainly distributed in PYH(302 in the PHF and 154 in the PWC).Family groups accounted for more than 50% of the total number of groups among both species,with Hooded Cranes forming more family groups than Siberian Cranes.Typically,these groups were formed of two adults with one offspring(Siberian Crane),and two adults with two offspring(Hooded Crane),with the mean family group size of the Siberian Crane and Hooded Crane being respectively 2.65±0.53(n=43) and 3.09±0.86(n=47) individuals per group.The mean collective group size of the Siberian Crane and Hooded Crane included 28.09±24.94(n=23) and 28.94±27.97(n=16) individuals per group,respectively,with the proportion of juveniles among Hooded Cranes being more than double that seen among the Siberian Cranes.展开更多
Background:Gut microbiota play crucial roles in host health.Wild birds and domestic poultry often occupy sympatric habitats,which facilitate the mutual transmission of intestinal microbes.However,the distinct intestin...Background:Gut microbiota play crucial roles in host health.Wild birds and domestic poultry often occupy sympatric habitats,which facilitate the mutual transmission of intestinal microbes.However,the distinct intestinal microbial communities between sympatric wild birds and poultry remain unknown.At present,the risk of interspecies transmission of pathogenic bacteria between wild and domestic host birds is also a research hotspot.Methods:This study compared the intestinal bacterial communities of the overwintering Hooded Crane(Grus monacha)and the Domestic Goose(Anser anser domesticus)at Shengjin Lake,China,using Illumina high-throughput sequencing technology(Mi-Seq platform).Results:Our results revealed that Firmicutes,Actinobacteria,Proteobacteria,Bacteroidetes and Chloroflexi were the dominant bacterial phyla in both hosts.The gut bacterial community composition differed significantly between sympatric Hooded Cranes and Domestic Geese.However,the hosts exhibited little variation in gut bacterial alphadiversity.The relative abundance of Firmicutes was significantly higher in the guts of the Hooded Cranes,while the relative abundances of Actinobacteria,Proteobacteria,Bacteroidete and Chloroflexi were significantly higher in guts of Domestic Geese.Moreover,a total of 132 potential pathogenic operational taxonomic units(OTUs)were detected in guts of Hooded Cranes and Domestic Geese,and 13 pathogenic OTUs(9.8%)were found in both host guts.Pathogenic bacterial community composition and diversity differed significantly between hosts.Conclusions:The results showed that the gut bacterial community composition differs significantly between sympatric Hooded Cranes and Domestic Geese.In addition,potential pathogens were detected in the guts of both Hooded Cranes and Domestic Geese,with 13 pathogenic OTUs overlapping between the two hosts,suggesting that more attention should be paid to wild birds and poultry that might increase the risk of disease transmission in conspecifics and other mixed species.展开更多
Background:The composition of intestinal microflora in animals is affected by cross-species transmission.In a nature reserve,the foraging sites of waterbirds are relatively fixed,but frequently close to residential ar...Background:The composition of intestinal microflora in animals is affected by cross-species transmission.In a nature reserve,the foraging sites of waterbirds are relatively fixed,but frequently close to residential areas and can also be visited by domestic fowls.It is easy to result in the trans-species-flock dispersal of gut microbes between the wild birds and domestic fowls.The effects of the variable foraging site distances on the gut microbe structures of the waterbirds and the sympatric domestic fowls are currently unclear,and further research is required to evaluate the impacts of geographic location on cross-infection.Methods:Illumina high-throughput sequencing and bioinformatics analysis software were utilized to compare and analyze the composition of gut microbes from the fecal samples of Hooded Cranes(HC;Grus monacha)and two groups of Domestic Ducks(Anas platyrhynchos domesticus)that foraged at 1 km(ducks in near areas,D-N),and 4 km(ducks in far areas,D-F)away from the habitats of the Hooded Cranes at Shengjin Lake,China.Results:The results showed that there were significant differences in the alpha-diversity of the gut bacteria in the HC,D-N,and D-F samples under the interspecific distance factor.The dominant bacterial phyla,Cyanobacteria and Proteobacteria,showed correlations with distance for each host.The D-N group had more diverse intestinal flora than the D-F,as they were physically closer to the HC and had more indirect contact and cross-transmission of their gut microbes.More potentially pathogenic bacterial sequences,and Operational Taxonomic Units(OTUs)were found in the D-N than in HC and D-F.Conclusions:Hooded Cranes and the Domestic Duck populations at variable distances from the cranes showed significant differences in their intestinal bacteria and potentially pathogenic bacteria.The closer the foraging sites were,the easier the intestinal flora spread across species.The results provide a basis for determining the safe distance between wild birds and domestic fowls in a nature reserve.展开更多
Background: The Hooded Crane(Grus monacha) is listed as a vulnerable species by IUCN. Knowledge about the migration of the Hooded Crane is still limited. Here we reported the spatio-temporal migration patterns of Hood...Background: The Hooded Crane(Grus monacha) is listed as a vulnerable species by IUCN. Knowledge about the migration of the Hooded Crane is still limited. Here we reported the spatio-temporal migration patterns of Hooded Cranes wintering in Izumi, Japan, as well as important stopover areas for their conservation.Methods: Four adult and five subadult cranes, all wintering in Izumi, Japan, were fitted with satellite transmitters(GPS–GSM system) at their stopover sites in northeastern China in 2014 and 2015. We analyzed the time and duration of adults and subadults in spring and autumn migration, as well as the time and duration they stayed in breeding and wintering ground. In addition, we analyzed the land use of the cranes in stopover areas.Results: Adult cranes took much longer time to migrate both north in spring(mean days) compared with subadult cranes(15.3 and 5.2 days, respectively). H= 44.3 days) and south in fall(mean = 54.0 owever, the subadults had longer wintering(mean = 149.8 days) and nomadic(breeding season for adults) seasons(mean d with adults(133.8 and 122.3 days, respectively). Three important stopover areas have been= 196.8 days) compare identified: the region around Muraviovka Park in Russia, the Songnen Plain in China, and the west coast of South Korea, where cranes spent most of their migration time(62.2 and 85.7% in spring and autumn, respectively). During migration, nomadic period and winter, Hooded Cranes usually stay in croplands for resting and feeding. In non-wintering season, less than 6% of stopover sites were located within protected areas.Conclusion: Overall, our results contribute to understanding the annual spatio-temporal migration patterns of Hooded Cranes in the eastern flyway, and planning conservation measures for this species.展开更多
Background:The intestinal microbiota play remarkable roles in maintaining the health of their hosts.Recent studies focused on gut bacterial diversity in birds and poultry,with little information about the ecological f...Background:The intestinal microbiota play remarkable roles in maintaining the health of their hosts.Recent studies focused on gut bacterial diversity in birds and poultry,with little information about the ecological functions of their gut fungal community.Methods:The high-throughput sequencing was applied to compare intestinal fungal community structure between Hooded Crane(Grus monacha)and Domestic Goose(Anser anser domesticus),and infer the potential pathogens of each species at Shengjin Lake of China.Results:Intestinal fungal alpha diversity was higher in Hooded Crane than Greylag Goose(Anser anser).Gut fungal community composition showed dramatic shifts between the two species.Hooded Cranes mainly eat Vallisneria natans and Potamogeton malaianus,while artificial hurl food(i.e.,paddy)was the main food resource for Domestic Geese,suggesting that the variations in fungal community might be induced by different diets between the two hosts.Two enriched genera(i.e.,Acremonium and Rhodotorula)which could increase host's digestion were detected in guts of Hooded Cranes.In addition,there were 42 pathogenic amplicon sequence variants(ASVs),17%of which shared in Hooded Crane and Greylag Goose.The Hooded Crane had higher gut fungal pathogenic diversity and abundance relative to Greylag Goose.Conclusions:The study demonstrated that divergence in intestinal fungal community structure might be induced by different diets between wintering Hooded Crane and Domestic Goose.Hooded Crane might rely more on their gut fungal taxa to acquire nutrients from indigestible food resources.Our study also implied that more research should focus on intestinal pathogens in wild birds and domestic poultry,as they might increase risk of disease in other animals,even human beings.The degree of cross infection in pathogens among wild birds and sympatric poultry should be clearly verified in future study.展开更多
Background: Wetland loss and degradation result in a reduction in the availability and quality of food for wintering waterbirds. Birds normally modify their foraging behavior to adapt to variations in food availabilit...Background: Wetland loss and degradation result in a reduction in the availability and quality of food for wintering waterbirds. Birds normally modify their foraging behavior to adapt to variations in food availability. In this study, we compared shifts in foraging behavior of Hooded Cranes(Grus monacha) in three different habitats at Shengjin Lake, China to understand the response of these cranes to changes in habitat.Methods: We investigated the food density and foraging behavior of Hooded Cranes in Shengjin Lake National Nature Reserve from November 2014 to April 2015. We used regression equations to describe the changes in food density. A total of 397 behavioral observations were used in the analyses of their foraging efforts. We fitted a candidate set of generalized mixed linear models to analyze the relationship of foraging efforts and food density. We used a method of information theory to guide the selection of the model and Akaike's Information Criterion to calculate the value of each model. The relationship between food density, disturbances and foraging behavior was illustrated using a generalized linear model.Results: Along with the temporal variation and exploitation of food biomass, the food density varied widely among foraging sites. During the early winter period, foraging efforts were more pronounced in the paddy fields and meadows but not significantly different among the three habitats. The cranes spent more foraging effort in the paddy fields and meadows during the middle stage and in the meadows and mudflats during the late winter. The results of the generalized linear model showed that food density and disturbances had different effects on the rate of foraging success during the winter, while the effect of foraging effort was not significant. Furthermore, the rate of feeding success was markedly affected by disturbances in the paddy fields. The combined action of food density and disturbances had a significant effect on the rate of foraging success in the meadows, while the effect of foraging effort was also not significant in three habitats.Conclusions: Changes in foraging behavior were significant in three habitats, which were affected by food density and disturbances. The rate of foraging success increased in the habitat with low food density and low disturbances to increase the foraging efficiency in the lake. With abundant food and a high level of disturbance, the rate of foraging success decreased to ensure more secure access to food.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31172117)the Graduate Student Innovation Research Projects of Anhui University(Grant No.yqh100118)the Anhui Academic and Technical Leader Fund
文摘The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource utilization, including partitioning, in degraded wetlands has become a hot issue in ecological studies of wintering waterbirds. In order to have an insight into the habitat utilization and resource partitioning between a Hooded Crane(Grus monacha) population and the guild of three goose species, i.e., Anser fabalis, A. albifrons and A. erythropus wintering in lake wetlands, we carried out a study at Shengjin Lake National Nature Reserve from November 2011 to April 2012. We surveyed the Hooded Cranes and goose guild foraging in various habitats during the wintering periods with a combined method of fixed route searching and fixed site observations. Resource partitioning was studied by means of calculating habitat utilization rates and the width and overlap of spatial niches. The results showed that the habitat utilization rate and the width of spatial niches of the Hooded Crane population and goose guild shifted with the season. The habitat utilization rates of the cranes in grasslands were high at all three wintering stages. The habitat utilization rates were 0.454, 0.435 and 0.959 respectively for the Hooded Cranes and 0.627, 0.491 and 0.616 for the goose guild. This suggests that the overlap in grasslands was higher between cranes and goose guild. Most habitats were accessible at the middle stage, so the width of the spatial niche of the cranes(1.099) and goose guild(1.133) both reached their peak at this stage. The greatest niche overlap was 0.914 for these two groups at the late stage, followed by 0.906 at the middle stage and the smallest was 0.854 at the early stage. Ecological response to the changes in habitats of wintering waterbirds was clearly shown in the dynamic variations of the niche of both the Hooded Cranes and the three goose species. Coexistence among waterbirds was achieved by regulation of niche width to reduce niche overlap and relieve interspecific resource partitioning.
基金Supported by the Special Fund for the Industrial Science and Technology Construction of Department of Agriculture(201202092-6)~~
文摘[Objective] This study aimed to explore the biological habits of Scirothrips dorsalis Hood and methods for controlling this pest. [Method] From 2009 to 2011, the biological habits of Scirothrips dorsalis Hood and the regularity of its occurrence on mangoes were investigated at the experimental base of the Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences and Shuanghongqiao Mango Orchard in Baoshan, Yunnan Province. In addition, a field trial on the effects of four medicaments on controlling this pest was also conducted. [Result] The result showed that Scirothrips dorsalis Hood completed 10-12 genera- tions per year in Baoshan area, and the peak period of its incidence was from February to April. The results of the pest control testing showed that at 0.05 level, there were significant differences of effect on pest controlling among the treatments I, II and IV, and the treatment III showed significant differences of controlling effect with the treatment IV, while no significant differences with either the treatment I or the treatment II; at 0.01 level, there was no significant difference among the treat- ments I, II and III, while all the three treatments showed significant differences with treatment IV. [Conclusion] This study revealed that the occurrence and the severity of Scirothrips dorsalis Hood on mangoes in Baoshan, Yunnan Province. In addition, pesticides with certain efficacy on controlling Scirothrips dorsalis Hood were screened, which provides more options for fruit growers to control this pest on mangoes.
基金supported by the staff of the Shengjin Lake National Nature Reservethe National Natural Science Foundation of China(Grant no.31172117,31472020)the Graduate Student Innovation Research Projects of Anhui University(YQH100270)for financial support
文摘Background:Food abundance and availability affect flock patterns of foraging birds.Cost and risk tradeoffs are especially critical for flocks of wintering waterbirds foraging in lake wetlands.Waterbirds losing suitable habitats face insufficient food supplies and high levels of disturbance,affecting their foraging activities.Our objective was to study the effects of food abundance and disturbances on flock size and the structure of Hooded Crane flocks wintering at Shengjin Lake and,as well,to understand the response of wintering waterbirds to habitat degradation for future management decisions and protection of the population.Methods:We investigated food abundance,disturbances and flock foraging activities of the wintering Hooded Crane in several foraging habitats of Shengjin Lake from November 2013 to April 2014.Flock size and structure were observed by scan sampling.Data on food abundance and disturbances were collected by sampling.Flock size and structure were compared among three wintering stages.The relationship between food resources,disturbances and flock size were illustrated using a generalized linear model.Results:In the early and middle wintering periods,the Hooded Crane used paddy fields as its major foraging habitat,where the number of foraging birds and flocks were the highest.During the late period,the cranes took to meadows as their major foraging habitat.The variation among foraging flock was mainly embodied in the size of the flocks,while the age composition of these flocks did not change perceptibly.Family flocks were notably different from flock groups in size and age composition.The results of a generalized linear model showed that the food abundance had a marked effect on foraging flock size and age composition,while disturbances had a significant effect only on flock size.From our analysis,it appeared that the combined effect of the two variables was significant on the size of the foraging flock,but had less impact on age composition.Conclusions:Food abundance and disturbances affected the flock size of the Hooded Crane.With abundant food and high disturbances,flock sizes increased owing to cooperation in foraging.To avoid competition and maximize foraging benefits,flock size reduces with an abundance of food but low disturbance.By trading off risks and costs,the cranes showed flexible flock distributions and a variety of foraging strategies to maximize benefits and to improve their fitness.
基金Supported by National Natural Science Foundation of China(Grant Nos.51576036,51476192)Science and Technology Development Planning Foundation of Jilin Province of China(Grant No.20140204040SF)
文摘Abstract Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam tur- bine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal design of its structure without consideration of the wet steam condensing flow and the exhaust hood coupled with the front and rear parts. To better understand the aerodynamic performance influenced by the tilt angle of flow guide inside a diffuser, taking a 600 MW steam turbine as an example, a numerical simulator CFX is adopted to solve compressible three-dimensional （3D） Reynolds time-aver- aged N-S equations and standard k-e turbulence model. And the exhaust hood flow field influenced by different tilt angles of flow guide is investigated with consideration of the wet steam condensing flow and the exhaust hood coupled with the last stage blades and the condenser throat. The result shows that the total pressure loss coefficient and the static pressure recovery coefficient of exhaust hood change regularly and monotonously with the gradual increase of tilt angle of flow guide. When the tilt angle of flow guide is within the range of 30~ to 40~, the static pressure recovery coefficient is in the range of 15.27% to 17.03% and the total pressure loss coefficient drops to approximately 51%, the aerodynamic performance of exhaust hood is significantly improved. And the effectiveenthalpy drop in steam turbine increases by 0.228% to 0.274%. It is feasible to obtain a reasonable title angle of flow guide by the method of coupling the last stage and the condenser throat to exhaust hood in combination of the wet steam model, which provides a practical guidance to flow guide transformation and optimal design in exhaust hood.
基金supported by the National Natural Science Foundation of China(Grant no.31172117 and 31472020)the Graduate Student Innovation Research Projects of Anhui University(YQ 01001770)
文摘Background:The ideal habitat use of waterbirds can be considered to be fixed,but current habitat use depends on environmental conditions,especially those of food characteristics,considered crucial to their use of habitats.Understanding how waterbirds respond to variation in food availability at degraded wetland sites and change their habitat use patterns over spatial and temporal scales should direct future conservation planning.The objectives of this study were to identify these spatial-temporal foraging habitat use patterns of Hooded Cranes(Grus monacha)and their relationship with food characteristics in the severely degraded wetlands of the Shengjin and Caizi lakes along with the Yangtze River floodplain.Methods:We investigated the changes in food characteristics,relative abundance and density of Hooded Cranes in various habitat types across three winter periods from November 2012 to April 2013.We examined the effect of these winter periods and habitat types on the pattern of use by the cranes and explored the relationship between these patterns and food characteristics using linear regression.Results:The food characteristics and habitat use clearly changed over spatial-temporal scales.In the early and mid-winter periods,the most abundant,accessible and frequented food resources were found in paddy fields,while in the late period the more abundant food were available in meadows,which then replaced the paddy fields.There were fewer effects of winter periods,habitat types and their interactions on habitat use patterns except for the effect of habitat types on the relative abundance,determined as a function of food abundance,but independent of food depth and sediment permeability.Conclusions:In response to the degradation and loss of lake wetlands,the cranes shifted their habitat use patterns by making tradeoffs between food abundance and accessibility over spatial-temporal scales that facilitated their survival in the mosaic of these lake wetlands.
基金supported by the National Natural Science Foundation of China(Grant no.31172117,31472020)the Graduate Student Innovation Research Projects of Anhui University(YQH100269)
文摘Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temporal-spatial patterns of foraging activities.It is of considerable importance to investigate the effect of these fluctuations on food availability for wintering Hooded Cranes and their foraging response to these changes.Understanding their behavior patterns is beneficial in protecting the wintering crane population and restoring their wintering habitats.Methods:A field survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014.Habitat variables,as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during five stages of water level fluctuation were collected.Based on this data we analyzed the relationship of foraging behavior relative to water level fluctuations and habitat types.Results:The foraging habitats used by Hooded Cranes varied at the different water level stages.As the water level decreased,the use of meadows and mudflats increased.When the water dropped to its lowest level,the use by the Hooded Crane in the mudflats reached a peak.There were statistically significant differences in time budget in the three types of habitats over the five stages of the water level.In the mudflats,the foraging behavior and maintenance behavior varied significantly with the water level,while the alert behavior showed little variation.Analysis of a generalized linear model showed that the five water level stages and three habitat types had a significant effect on foraging behavior,while the combined effect of these two variables was significant on the foraging time budget and the length of foraging activity of the Hooded Crane.Conclusions:With the decrease in the water level,the use of mudflats by Hooded Cranes increased correspondingly.Food availability in different habitats was affected by changes in the water level.The Hooded Crane adjusted its foraging patterns and made full use of the three available types of habitat in order to acquire enough food in response to fluctuations in the water level.
基金supported by the National Natural Science Foundation of China (31172117)the Graduate Student Innovation Research Projects of Anhui University (YQH100611)
文摘Background: Parasites have adverse effects on the life and survival of many migratory waterbirds, especially birds on the endangered species list. Hooded Cranes are large migratory colonial waterbirds wintering in wetlands,which are prone to parasite infection, thus monitoring the diversity of parasites is important for sound wetland management and protection of this species.Methods: From November 2012 to April 2013, we collected 821 fresh faecal samples from the three lakes(Poyang,Caizi and Shengjin Lake) in the lower and middle Yangtze River floodplain, and detected with saturated brine floating and centrifugal sedimentation methods. Parasite eggs were quantified with a modified Mc Master's counting method.Results: In this study, 11 species of parasites were discovered, i.e., two coccidium(Eimeria gruis, E. reichenowi), five nematodes(Capillaria sp., Strongyloides sp., Ascaridia sp., Trichostrongylus sp., Ancylostomatidae), three trematodes(Echinostoma sp., Echinochasmus sp., Fasciolopsis sp.) and one cestode(Hymenolepis sp.). About 57.7% of the faecal samples showed parasitic infection. All species of parasites were found at the three sites except Hymenolepis which was not found at Poyang Lake. While most samples were affected by only one or two species of parasites, infection by Eimeria spp. was the most common(53.1%). From One-Way ANOVA analysis of the three lakes, parasite species richness index(p = 0.656), diversity index(p = 0.598) and evenness index(p = 0.612) showed no significant difference. According to the statistical analysis of our data, there were no significant difference in parasite species richness index(p = 0.678) and evenness index(p = 0.238) between wintering periods, but a strong difference in diversity index(p < 0.05).Conclusions: Our study suggests that in the wintering Hooded Crane populations, parasite diversity is more sensitive to changes in the overwintering periods than to locations. This also indicates that with the limitations of migration distance, the parasites may not form the differentiation in Hooded Crane populations of the three lakes.
基金supported by the Shanghai Leading Academic Discipline Project(B604)the Henan Science and Technology Breakthrough Major Project(102102210440)+1 种基金the High School Funding Scheme for Key Young Teachersthe Education Department of Henan Province,2010
文摘A novel hood structure has been designed for the dust control system in the foundry in order to improve the working environment. A composite strategy has been applied for comparative analysis of the optimal venting volume and the airflow distribution between the conventional hood and the novel one in this study. A Computational Fluid Dynamic (CFD) method is used to simulate the airflow fields and dust-polluted air moving paths. The CFD results show that a two-outlet hood, with one outlet located on the left of the hood, is better for improving dust-polluted air than the hood with one outlet only. It can be concluded that the number of the outlets as well as their location on the hood has a significant influence on the air flow pattern in the hood. The optimal venting volume is also a major consideration that is discussed in the study. The venting volume should be designed by considering both the effective level of air flow velocity around the dust source and the energy saving. The optimal airflow distribution may reduce the turbulence in the hood system.
文摘A new local exhaust ventilation hood is presented. First, the test system inlaboratory room is established. Secondly a mathematical model is developed in terms of the stokesstream function, and the governing equation is solved using finite-difference techniques. Theinjection flow of the exhaust hood is treated as a boundary condition of the main flow. Experimentsresults well agree with the solution of theoretical prediction. The model can, therefore, be used todesign this kind of Aaberg hood. Thirdly the important parameters affecting the performance ofAaberg exhaust hood are taken into account. In the mean time the connection of these parameters isdeduced by multivariate linear regression based on the experimental results. The work is usefulwhether in designing this kind of local ventilation Aaberg exhaust hood or in predicting the hood'swork performance.
基金supported by the National Natural Science Foundation of China(3126051731101651)
文摘Both the Siberian Crane(Leucogeranus leucogeranus) and Hooded Crane(Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies.To document the current size of their respective populations and characterize their groups,between October 2012 and April 2013 we undertook fieldwork at four nature reserve areas within the Poyang Lake wetlands.We divided Poyanghu National Nature Reserve(PYH) into the Wucheng(PWC) and Hengfeng areas(PHF),because each are each located in different counties.Our fieldwork showed that the Siberian Crane occurred mainly in PYH(364 in the PHF,158 in the PWC) and the Nanjishan Wetland National Nature Reserve(NJS,with 200 individuals).The Hooded Crane was mainly distributed in PYH(302 in the PHF and 154 in the PWC).Family groups accounted for more than 50% of the total number of groups among both species,with Hooded Cranes forming more family groups than Siberian Cranes.Typically,these groups were formed of two adults with one offspring(Siberian Crane),and two adults with two offspring(Hooded Crane),with the mean family group size of the Siberian Crane and Hooded Crane being respectively 2.65±0.53(n=43) and 3.09±0.86(n=47) individuals per group.The mean collective group size of the Siberian Crane and Hooded Crane included 28.09±24.94(n=23) and 28.94±27.97(n=16) individuals per group,respectively,with the proportion of juveniles among Hooded Cranes being more than double that seen among the Siberian Cranes.
基金supported by the National Natural Science Foundation of China(Grant Nos.31772485 and 31801989)。
文摘Background:Gut microbiota play crucial roles in host health.Wild birds and domestic poultry often occupy sympatric habitats,which facilitate the mutual transmission of intestinal microbes.However,the distinct intestinal microbial communities between sympatric wild birds and poultry remain unknown.At present,the risk of interspecies transmission of pathogenic bacteria between wild and domestic host birds is also a research hotspot.Methods:This study compared the intestinal bacterial communities of the overwintering Hooded Crane(Grus monacha)and the Domestic Goose(Anser anser domesticus)at Shengjin Lake,China,using Illumina high-throughput sequencing technology(Mi-Seq platform).Results:Our results revealed that Firmicutes,Actinobacteria,Proteobacteria,Bacteroidetes and Chloroflexi were the dominant bacterial phyla in both hosts.The gut bacterial community composition differed significantly between sympatric Hooded Cranes and Domestic Geese.However,the hosts exhibited little variation in gut bacterial alphadiversity.The relative abundance of Firmicutes was significantly higher in the guts of the Hooded Cranes,while the relative abundances of Actinobacteria,Proteobacteria,Bacteroidete and Chloroflexi were significantly higher in guts of Domestic Geese.Moreover,a total of 132 potential pathogenic operational taxonomic units(OTUs)were detected in guts of Hooded Cranes and Domestic Geese,and 13 pathogenic OTUs(9.8%)were found in both host guts.Pathogenic bacterial community composition and diversity differed significantly between hosts.Conclusions:The results showed that the gut bacterial community composition differs significantly between sympatric Hooded Cranes and Domestic Geese.In addition,potential pathogens were detected in the guts of both Hooded Cranes and Domestic Geese,with 13 pathogenic OTUs overlapping between the two hosts,suggesting that more attention should be paid to wild birds and poultry that might increase the risk of disease transmission in conspecifics and other mixed species.
基金The work was supported by the National Natural Science Foundation of China(Grant No.31772485).
文摘Background:The composition of intestinal microflora in animals is affected by cross-species transmission.In a nature reserve,the foraging sites of waterbirds are relatively fixed,but frequently close to residential areas and can also be visited by domestic fowls.It is easy to result in the trans-species-flock dispersal of gut microbes between the wild birds and domestic fowls.The effects of the variable foraging site distances on the gut microbe structures of the waterbirds and the sympatric domestic fowls are currently unclear,and further research is required to evaluate the impacts of geographic location on cross-infection.Methods:Illumina high-throughput sequencing and bioinformatics analysis software were utilized to compare and analyze the composition of gut microbes from the fecal samples of Hooded Cranes(HC;Grus monacha)and two groups of Domestic Ducks(Anas platyrhynchos domesticus)that foraged at 1 km(ducks in near areas,D-N),and 4 km(ducks in far areas,D-F)away from the habitats of the Hooded Cranes at Shengjin Lake,China.Results:The results showed that there were significant differences in the alpha-diversity of the gut bacteria in the HC,D-N,and D-F samples under the interspecific distance factor.The dominant bacterial phyla,Cyanobacteria and Proteobacteria,showed correlations with distance for each host.The D-N group had more diverse intestinal flora than the D-F,as they were physically closer to the HC and had more indirect contact and cross-transmission of their gut microbes.More potentially pathogenic bacterial sequences,and Operational Taxonomic Units(OTUs)were found in the D-N than in HC and D-F.Conclusions:Hooded Cranes and the Domestic Duck populations at variable distances from the cranes showed significant differences in their intestinal bacteria and potentially pathogenic bacteria.The closer the foraging sites were,the easier the intestinal flora spread across species.The results provide a basis for determining the safe distance between wild birds and domestic fowls in a nature reserve.
基金funded by the National Natural Science Foundation of China(Grant No.31570532)
文摘Background: The Hooded Crane(Grus monacha) is listed as a vulnerable species by IUCN. Knowledge about the migration of the Hooded Crane is still limited. Here we reported the spatio-temporal migration patterns of Hooded Cranes wintering in Izumi, Japan, as well as important stopover areas for their conservation.Methods: Four adult and five subadult cranes, all wintering in Izumi, Japan, were fitted with satellite transmitters(GPS–GSM system) at their stopover sites in northeastern China in 2014 and 2015. We analyzed the time and duration of adults and subadults in spring and autumn migration, as well as the time and duration they stayed in breeding and wintering ground. In addition, we analyzed the land use of the cranes in stopover areas.Results: Adult cranes took much longer time to migrate both north in spring(mean days) compared with subadult cranes(15.3 and 5.2 days, respectively). H= 44.3 days) and south in fall(mean = 54.0 owever, the subadults had longer wintering(mean = 149.8 days) and nomadic(breeding season for adults) seasons(mean d with adults(133.8 and 122.3 days, respectively). Three important stopover areas have been= 196.8 days) compare identified: the region around Muraviovka Park in Russia, the Songnen Plain in China, and the west coast of South Korea, where cranes spent most of their migration time(62.2 and 85.7% in spring and autumn, respectively). During migration, nomadic period and winter, Hooded Cranes usually stay in croplands for resting and feeding. In non-wintering season, less than 6% of stopover sites were located within protected areas.Conclusion: Overall, our results contribute to understanding the annual spatio-temporal migration patterns of Hooded Cranes in the eastern flyway, and planning conservation measures for this species.
基金supported by the National Natural Science Foundation(31801989)the Natural Science Foundation of Education Committee(KJ2018A0001)the Scientific Research Foundation(J01006160,J05011710,S020118002/101)。
文摘Background:The intestinal microbiota play remarkable roles in maintaining the health of their hosts.Recent studies focused on gut bacterial diversity in birds and poultry,with little information about the ecological functions of their gut fungal community.Methods:The high-throughput sequencing was applied to compare intestinal fungal community structure between Hooded Crane(Grus monacha)and Domestic Goose(Anser anser domesticus),and infer the potential pathogens of each species at Shengjin Lake of China.Results:Intestinal fungal alpha diversity was higher in Hooded Crane than Greylag Goose(Anser anser).Gut fungal community composition showed dramatic shifts between the two species.Hooded Cranes mainly eat Vallisneria natans and Potamogeton malaianus,while artificial hurl food(i.e.,paddy)was the main food resource for Domestic Geese,suggesting that the variations in fungal community might be induced by different diets between the two hosts.Two enriched genera(i.e.,Acremonium and Rhodotorula)which could increase host's digestion were detected in guts of Hooded Cranes.In addition,there were 42 pathogenic amplicon sequence variants(ASVs),17%of which shared in Hooded Crane and Greylag Goose.The Hooded Crane had higher gut fungal pathogenic diversity and abundance relative to Greylag Goose.Conclusions:The study demonstrated that divergence in intestinal fungal community structure might be induced by different diets between wintering Hooded Crane and Domestic Goose.Hooded Crane might rely more on their gut fungal taxa to acquire nutrients from indigestible food resources.Our study also implied that more research should focus on intestinal pathogens in wild birds and domestic poultry,as they might increase risk of disease in other animals,even human beings.The degree of cross infection in pathogens among wild birds and sympatric poultry should be clearly verified in future study.
基金supported by the National Natural Science Foundation of China (Grant No.31472020,31172117)the Graduate Student Innovation Research Projects of Anhui University (YQH100287)
文摘Background: Wetland loss and degradation result in a reduction in the availability and quality of food for wintering waterbirds. Birds normally modify their foraging behavior to adapt to variations in food availability. In this study, we compared shifts in foraging behavior of Hooded Cranes(Grus monacha) in three different habitats at Shengjin Lake, China to understand the response of these cranes to changes in habitat.Methods: We investigated the food density and foraging behavior of Hooded Cranes in Shengjin Lake National Nature Reserve from November 2014 to April 2015. We used regression equations to describe the changes in food density. A total of 397 behavioral observations were used in the analyses of their foraging efforts. We fitted a candidate set of generalized mixed linear models to analyze the relationship of foraging efforts and food density. We used a method of information theory to guide the selection of the model and Akaike's Information Criterion to calculate the value of each model. The relationship between food density, disturbances and foraging behavior was illustrated using a generalized linear model.Results: Along with the temporal variation and exploitation of food biomass, the food density varied widely among foraging sites. During the early winter period, foraging efforts were more pronounced in the paddy fields and meadows but not significantly different among the three habitats. The cranes spent more foraging effort in the paddy fields and meadows during the middle stage and in the meadows and mudflats during the late winter. The results of the generalized linear model showed that food density and disturbances had different effects on the rate of foraging success during the winter, while the effect of foraging effort was not significant. Furthermore, the rate of feeding success was markedly affected by disturbances in the paddy fields. The combined action of food density and disturbances had a significant effect on the rate of foraging success in the meadows, while the effect of foraging effort was also not significant in three habitats.Conclusions: Changes in foraging behavior were significant in three habitats, which were affected by food density and disturbances. The rate of foraging success increased in the habitat with low food density and low disturbances to increase the foraging efficiency in the lake. With abundant food and a high level of disturbance, the rate of foraging success decreased to ensure more secure access to food.
