For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological...For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.展开更多
The dynamics of rhizosphere microbial communities is important for plant health and productivity, and can be influenced by soil type, plant species or genotype, and plant growth stage. A pot experiment was carried out...The dynamics of rhizosphere microbial communities is important for plant health and productivity, and can be influenced by soil type, plant species or genotype, and plant growth stage. A pot experiment was carried out to examine the dynamics of microbial communities in the rhizosphere of two soybean genotypes grown in a black soil in Northeast China with a long history of soybean cultivation. The two soybean genotypes, Beifeng 11 and Hai 9731, differing in productivity were grown in a mixture of black soil and siliceous sand. The bacterial communities were compared at three zone locations including rhizoplane, rhizosphere, and bulk soil at the third node (V3), early flowering (R1), and early pod (R3) stages using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DCGE) of 16S rDNA. The results of principal component analyses (PCA) showed that the bacterial community structure changed with growth stage. Spatially, the bacterial communities in the rhizoplane and rhizosphere were significantly different from those in the bulk soil. Nevertheless, the bacterial communities in the rhizoplane were distinct from those in the rhizosphere at the V3 stage, while no obvious differences were found at the R1 and R3 stages. For the two genotypes, the bacterial community structure was similar at the V3 stage, but differed at the R1 and R3 stages. In other words, some bacterial populations became dominant and some others recessive at the two later stages, which contributed to the variation of the bacterial community between the two genotypes. These results suggest that soybean plants can modify the rhizosphere bacterial communities in the black soil, and there existed genotype-specific bacterial populations in the rhizospbere, which may be related to soybean productivity.展开更多
Competitive use of transboundary freshwater resources is becoming one of the key factors influencing regional peace and political relationship among states.In China, 18 major international river basins are concentrate...Competitive use of transboundary freshwater resources is becoming one of the key factors influencing regional peace and political relationship among states.In China, 18 major international river basins are concentrated in three regions, of which the total annual outflow at the border is 7320×108 m3, occupying 26.8% of the total annual runoff of China, and the inflow at the border is only 172×108 m3.In this paper, we analyzed the major drivers affecting shared water vulnerability in China, namely:(1) changes in physical conditions affecting the availability of water;(2) competing objectives between economic development and ecological conservation;(3) lack of emergency response mechanisms;(4) unsound administrative institutions;and(5) shortcomings in the development of regional cooperation based on transboundary waters.We concluded by identifying four pathways for reducing vulnerability:(1) encouraging scientific research cooperation;(2) constructing information-sharing channels;(3) establishing early-warning mechanisms;and(4) promoting further coordination and negotia-tion.展开更多
The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of ...The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to August,followed by a sharp increase from the middle of August,reaching a single maximum peak value of 2.2×105 cells L-1 in October.Temporal variation in abundance was positively correlated with dissolved nitrogen,but showed a significant inverse relationship to abundance of the dominant ciliates,Tintinnopsis lohmanni and Askenasia stellaris.The results provide statistical evidence that the number of P.minimum increased with increasing nitrogen,and the suppression or shortening of algal bloom may be associated with protozoan grazers,such as Tintinnopsis lohmanni,in mariculture ponds.展开更多
Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss...Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss Equation and county-level socioeconomic data to assess the changes in the ecosystem service of soil conservation between 2000 and 2010, and to analyze its spatial characteristics and driving factors in the southwestern China. The results showed that cropland in the southwestern China decreased by 3.74%, while urban land, forest, and grassland areas increased by 46.78%, 0.86%, and 1.12%, respectively. The soil conservation increased by 1.88 × 10^(11) kg, with deterioration only in some local areas. The improved and the degraded areas accounted for 6.41% and 2.44% of the total land area, respectively. Implementation of the Sloping Land Conversion Program and urbanization explained 57.80% and 23.90% of the variation in the soil conservation change, respectively, and were found to be the main factors enhancing soil conservation. The 2008 Wenchuan earthquake was one of the factors that led to the degradation of soil conservation. Furthermore, industrial adjustment, by increasing shares of Industry and Service and reducing those of Agriculture, has also promoted soil conservation. Our results quantitatively showed and emphasized the contributions to soil conservation improvement made by implementing ecological restoration programs and promoting urbanization. Consequently, these results provide basic information to improve our understanding of the effects of ecological restoration programs, and help guide future sustainable urban development and regional industrial restructuring.展开更多
Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negat...Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negative impacts. In this study, we propose an assessment concept framework model for indirect-direct-ecosystem service (IN-DI-ESS) driving forces within this context and method for index construction that considers the selection of a robust and parsimonious variable set. Factor analysis was integrated into two-stage data envelopment analysis (TS-DEA) to determine the driving forces and their effects on water conservation services in forest ecosystems at the provincial scale in China. The results showed the following. 1) Ten indicators with factor scores more than 0.8 were selected as the minimum data set. Four indicators comprising population density, per capita gross domestic product, irrigation efficiency, and per capita food consumption were the indirect driving factors, and six indicators comprising precipitation, farmland into forestry or pasture, forest cover, habitat area, water footprint, and wood extraction were the direct driving forces. 2) Spearman's rank correlation test was performed to compare the overall effectiveness in two periods: stage 1 and stage 2. The calculated coefficients were 0.245, 0.136, and 0.579, respectively, whereas the tabulated value was 0.562. This indicates that the driving forces obviously differed in terms of their contribution to the overall effectiveness and they caused changes in water conservation services in different stages. In terms of the variations in different driving force effects in the years 2000 and 2010, the overall, stage 1, and stage 2 variances were 0.020, 0.065, and 0.079 in 2000, respectively, and 0.018, 0.063, and 0.071 in 2010. This also indicates that heterogeneous driving force effects were obvious in the process during the same period. Identifying the driving forces that affect service changes and evaluating their efficiency have significant policy implications for the management of forest ecosystem services. Advanced effectiveness measures for weak regions could be improved in an appropriate manner. In this study, we showed that factor analysis coupled with TS-DEA based on the IN-D1-ESS framework can increase the parsimony of driving force indicators, as well as interpreting the interactions among indirect and direct driving forces with forest ecosystem water conservation services, and reducing the uncertainty related to the internal consistency during data selection.展开更多
Chiton(Ischnochiton hakodadensis) is one of marine mollusks well known for its eight separate shell plates. I. hakodadensis is important, which plays a vital role in the ecosystems it inhabits. So far, the genetic stu...Chiton(Ischnochiton hakodadensis) is one of marine mollusks well known for its eight separate shell plates. I. hakodadensis is important, which plays a vital role in the ecosystems it inhabits. So far, the genetic studies on the chiton are scarce due in part to insufficient genomic resources available for this species. In this study, we investigated the transcriptome of the chiton foot using Illumina sequencing technology. The reads were assembled and clustered into 256461 unigenes, of which 42247 were divided into diverse functional categories by Gene Ontology(GO) annotation terms, and 17256 mapped onto 365 pathways by KEGG pathway mapping. Meanwhile, a set of differentially expressed genes(DEGs) between distal and proximal muscles were identified as the foot adhesive locomotion associated, thus were useful for our future studies. Moreover, up to 679384 high-quality single nucleotide polymorphisms(SNPs) and 19814 simple sequence repeats(SSRs) were identified in this study, which are valuable for subsequent studies on genetic diversity and variation. The transcriptomic resource obtained in this study should aid to future genetic and genomic studies of chiton.展开更多
Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test t...Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group.展开更多
The exploration of ecological safety in tourism sites can provide a concrete path for sustainable tourism development in a region.Based on the“Driver-Pressure-State-Impact-Response”(DPSIR)model,we constructed an ind...The exploration of ecological safety in tourism sites can provide a concrete path for sustainable tourism development in a region.Based on the“Driver-Pressure-State-Impact-Response”(DPSIR)model,we constructed an index system for the evaluation of tourism ecological security(TES)in the Silk Road Economic Belt(SREB)from 2005 to 2020.This index system was used to explore the characteristics of spatial and temporal dynamic evolution with the help of entropy weight TOPSIS method,dynamic index of TES and Markov probability transfer matrix,and a standard deviational ellipse(SDE)model and GM(1,1)model were constructed for spatial pattern analysis and prediction.The results indicate four key aspects of this system.(1)In terms of spatiotemporal evolution,the tourism ecological safety index(TESI)of the SREB increased,the TES levels of the northwestern and southwestern provinces and cities differed significantly,and the quality conditions of TES in the southwestern provinces and cities were better than in the northwest.(2)In terms of dynamic evolutionary characteristics,the speed of change at each level of the SREB was slow,but the level of TES has improved.The TES level has not shifted by leaps and bounds,and the shifts in the level type show“path dependence”and“self-locking”effects.(3)In terms of spatial and temporal distribution patterns,the spatial pattern of TES in the SREB is a“northwest-southeast”movement trend,and the spatial distribution appeared as“aggregation”from 2005 to 2020.The prediction results show that the center of gravity of TES in the SREB will shift to the southeast from 2025 to 2035,and the spatial spillover effect will be reduced.(4)In terms of driving factors,the number of star-rated hotels,and the amounts of industrial wastewater emissions,tourism foreign exchange earnings,forest coverage,and other parameters are the key factors affecting TES,and the booming tourism industry requires the interconnection and interpenetration of various factors.The results of this study can provide a reference for tourism development and ecological environmental protection in the Silk Road Economic Belt.展开更多
The Cambrian explosion has long been a basic research frontier that concerns many scientific fields. Here we discuss the cause-effect links of the Cambrian explosion on the basis of first appearances of animal phyla i...The Cambrian explosion has long been a basic research frontier that concerns many scientific fields. Here we discuss the cause-effect links of the Cambrian explosion on the basis of first appearances of animal phyla in the fossil record, divergence time, environmental changes, Gene Regulatory Networks, and ecological feedbacks. The first appearances of phyla in the fos- sil record are obviously diachronous but relatively abrupt, concentrated in the first three stages of the Cambrian period (541- 514 Ma). The actual divergence time may be deep or shallow. Since the gene regulatory networks (GRNs) that control the de- velopment of metazoans were in place before the divergence, the establishment of GRNs is necessary but insufficient for the Cambrian explosion. Thus the Cambrian explosion required environmental triggers. Nutrient availability, oxygenation, and change of seawater composition were potential environmental triggers. The nutrient input, e.g., the phosphorus enrichment in the environment, would cause excess primary production, but it is not directly linked with diversity or disparity. Further in- crease of oxygen level and change of seawater composition during the Ediacaran-Cambrian transition were probably crucial environmental factors that caused the Cambrian explosion, but more detailed geochemical data are required. Many researchers prefer that the Cambrian explosion is an ecological phenomenon, that is, the unprecedented ecological success of ruetazoans during the Early Cambrian, but ecological effects need diverse and abundant animals. Therefore, the establishment of the eco- logical complexity among animals, and between animals and environments, is a consequence rather than a cause of the Cam- brian explosion. It is no doubt that positive ecological feedbacks could facilitate the increase of biodiversity. In a word, the Cambrian explosion happened when environmental changes crossed critical thresholds, led to the initial formation of the meta- zoan-doruinated ecosystem through a series of knock-on ecological processes, i.e., "ecological snowball" effects.展开更多
Ecological land can provide people with ecological products and ecological services;and it plays an important role in maintaining the health and safety of the ecosystem.With China’s rapid urbanization development,eco...Ecological land can provide people with ecological products and ecological services;and it plays an important role in maintaining the health and safety of the ecosystem.With China’s rapid urbanization development,ecological land has been invaded in large quantities,and damaged seriously,even resulting in loses of its ecological function.Based on land use data from 1995 to 2015,our study explores the spatial and temporal evolution of the damage or recovery of ecological land in the Yangtze River Economic Belt(YREB).Two spatial models,geographic detector and geographic weighted regression(GWR),were employed to assess the global effects and the local effects of the driving factors for ecological land change,respectively.Our study divided the ecological land change into five types based on the degree of change as severe damage,slight damage,unchanged,slight recovery,and obvious recovery.The results show that from 1995 to 2015,the total area of ecological land in the YREB increased initially and then decreased,but the overall trend was decreasing.The total damaged area was larger than the recovered area.Arable land and woodland both showed downward trends.In terms of ecological land change over the past 20 years,the type of unchanged had the largest area,followed by slight damage and slight recovery.Our study further revealed that ecological land change was the net result of the interaction of many factors,and the explanatory power between any two driving factors was greater than that of any individual driving factor.In addition,driving factors have different impacts on ecological land change in different geographical locations.This knowledge should help land managers and policymakers to be better informed when developing pertinent land use policies at the regional and local levels.The lessons can also be extended to other regions for better management of their ecological land for sustainable use.展开更多
Farmland abandonment is a global problem and considered one of the most important areas in land use change research. Farmland abandonment research currently focuses on understanding the factors that affect farmland ab...Farmland abandonment is a global problem and considered one of the most important areas in land use change research. Farmland abandonment research currently focuses on understanding the factors that affect farmland abandonment and developing scientific models to simulate farmland abandonment. The study reviewed the natural and political factors driving farmland abandonment and summarized the main models for farmland abandonment simulation together with their advantages and disadvantages. We discuss the main ecological effects of farmland abandonment and propose farmland abandonment research directions. The study found that:(1) the influence of labor cost change and ageing labor force on farmland abandonment needs further investigation,(2) simulation models for farmland abandonment must include the decision-making mechanism of individual farmers and focus on macro large-scale abandonment prediction models, and(3) the influence of farmland abandonment on landscape culture must be investigated in detail.展开更多
One approach to understand the importance of reproductive barriers to the speciation process is to study the break- down of barriers between formerly distinct species. One reproductive barrier, sexual isolation, reduc...One approach to understand the importance of reproductive barriers to the speciation process is to study the break- down of barriers between formerly distinct species. One reproductive barrier, sexual isolation, reduces gene flow between species through differences in mate preferences and mating signals and is likely important for species formation and maintenance. We measure sexual isolation in two limnetic-benthic threespine stickleback species pairs (Gasterosteus spp.). One species pair main- tains strong reproductive isolation while the other species pair has recently collapsed into a hybrid swarm. We compare the strength of sexual isolation in the hybridizing pair to the currently isolated pair. We provide the first evidence that sexual isolation has been lost in the hybridizing pair and show furthermore that preferences females have for conspecific mates and the traits they use to distinguish conspecific and heterospecific males contribute to this loss. This work highlights the fragility of reproductive isolation between young species pairs and considers the role of sexual isolation in speciation [Current Zoology 59 (5): 591-603, 2013].展开更多
Aims Intraspecific variation in plant traits has important consequences for individual fitness and herbivore foraging.For plants,trait variability across spatial dimensions is well documented.However,temporal dimensio...Aims Intraspecific variation in plant traits has important consequences for individual fitness and herbivore foraging.For plants,trait variability across spatial dimensions is well documented.However,temporal dimensions of trait variability are less well known,and may be influenced by seasonal differences in growing degree days(GDD),temperature and precipitation.Here,we aim to quantify intraspecific temporal variation in traits and the underlying drivers for four commonly occurring boreal plant species.Methods We sampled the elemental and stoichiometric traits(%C,%N,%P,C:N,C:P,N:P)of four common browse species'foliage across 2 years.Using a two-step approach,we first fitted generalized linear models(GzLM,n=24)to the species'elemental and stoichiometric traits,and tested if they varied across years.When we observed evidence for temporal variability,we fitted a second set of GzLMs(n=8)with temperature,productivity and moisture as explanatory variables.Important Findings We found no evidence of temporal variation for most of the elemental and stoichiometric traits of our four boreal plants,with two exceptions.Year was an important predictor for percent carbon across all four species(R^(2)=0.47-0.67)and for multiple elemental and stoichiometric traits in balsam fir(5/8,R2=0.29-0.67).Thus,variation in percent carbon was related to interannual differences,more so than nitrogen and phosphorus,which are limiting nutrients in the boreal forest.These results also indicate that year may explain more variation in conifers'stoichiometry than for deciduous plants due to life history differences.GDD was the most frequently occurring variable in the second round of models(8/8 times,R^(2)=0.21-0.41),suggesting that temperature is an important driver of temporal variation in these traits.展开更多
Wetlands store large amounts of carbon stocks and are essential in both global carbon cycling and regional ecosystem services.Understanding the dynamics of wetland carbon exchange is crucial for assessing carbon budge...Wetlands store large amounts of carbon stocks and are essential in both global carbon cycling and regional ecosystem services.Understanding the dynamics of wetland carbon exchange is crucial for assessing carbon budgets and predicting their future evolution.Although many studies have been conducted on the effects of climate change on the ecosystem carbon cycle,little is known regarding carbon emissions from the alpine wetlands in arid northwest China.In this study,we used an automatic chamber system(LI-8100A)to measure ecosystem respiration(ER)in the Bayinbuluk alpine wetland in northwest China.The ER showed a significant bimodal diurnal variation,with peak values appearing at 16:30 and 23:30(Beijing time,UTC+8).A clear seasonal pattern in ER was observed,with the highest value(19.38μmol m-2 s-l)occurring in August and the lowest value(0.11μmol m-2 s-1)occurring in late December.The annual ER in 2018 was 678 g C m-2 and respiration during the non-growing season accounted for 13%of the annual sum.Nonlinear regression revealed that soil temperature at 5 cm depth and soil water content(SwC)were the main factors controlling the seasonal variation in ER.The diurnal variation in ER was mainly controlled by air temperature and solar radiation.Higher temperature sensitivity(Qio)occurred under conditions of lower soil temperatures and medium SWC(25%≤SWC≤40%).The present study deepens our understanding of CO,emissions in alpine wetland ecosystems and helps evaluate the carbon budget in alpine wetlands in arid regions.展开更多
基金supported by the Guangxi Natural Science Foundation(2020GXNSFAA297266)Doctoral Research Foundation of Guilin University of Technology(GUTQDJJ2007059)Guangxi Hidden Metallic Mineral Exploration Key Laboratory。
文摘For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.
基金Project supported by the National Natural Science Foundation of China (Nos. 40671099 and 40701084)the Director Program of the Key Laboratory of Soybean Biology of Ministry of Education, China (No. SB05B02)
文摘The dynamics of rhizosphere microbial communities is important for plant health and productivity, and can be influenced by soil type, plant species or genotype, and plant growth stage. A pot experiment was carried out to examine the dynamics of microbial communities in the rhizosphere of two soybean genotypes grown in a black soil in Northeast China with a long history of soybean cultivation. The two soybean genotypes, Beifeng 11 and Hai 9731, differing in productivity were grown in a mixture of black soil and siliceous sand. The bacterial communities were compared at three zone locations including rhizoplane, rhizosphere, and bulk soil at the third node (V3), early flowering (R1), and early pod (R3) stages using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DCGE) of 16S rDNA. The results of principal component analyses (PCA) showed that the bacterial community structure changed with growth stage. Spatially, the bacterial communities in the rhizoplane and rhizosphere were significantly different from those in the bulk soil. Nevertheless, the bacterial communities in the rhizoplane were distinct from those in the rhizosphere at the V3 stage, while no obvious differences were found at the R1 and R3 stages. For the two genotypes, the bacterial community structure was similar at the V3 stage, but differed at the R1 and R3 stages. In other words, some bacterial populations became dominant and some others recessive at the two later stages, which contributed to the variation of the bacterial community between the two genotypes. These results suggest that soybean plants can modify the rhizosphere bacterial communities in the black soil, and there existed genotype-specific bacterial populations in the rhizospbere, which may be related to soybean productivity.
基金The National Key Project for Basic Research on Ecosystem Changes in Longitudinal Range-Gorge Region and Transboundary Eco-security of Southwest China,No.2003CB415105
文摘Competitive use of transboundary freshwater resources is becoming one of the key factors influencing regional peace and political relationship among states.In China, 18 major international river basins are concentrated in three regions, of which the total annual outflow at the border is 7320×108 m3, occupying 26.8% of the total annual runoff of China, and the inflow at the border is only 172×108 m3.In this paper, we analyzed the major drivers affecting shared water vulnerability in China, namely:(1) changes in physical conditions affecting the availability of water;(2) competing objectives between economic development and ecological conservation;(3) lack of emergency response mechanisms;(4) unsound administrative institutions;and(5) shortcomings in the development of regional cooperation based on transboundary waters.We concluded by identifying four pathways for reducing vulnerability:(1) encouraging scientific research cooperation;(2) constructing information-sharing channels;(3) establishing early-warning mechanisms;and(4) promoting further coordination and negotia-tion.
基金Supported by the National Natural Science Foundation of China (No. 40976075)a Post-Doctoral Fellowship of Inha University,a Grant from the Center of Excellence in Biodiversity Research,King Saud University and 111 project of China (No. B08049)
文摘The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to August,followed by a sharp increase from the middle of August,reaching a single maximum peak value of 2.2×105 cells L-1 in October.Temporal variation in abundance was positively correlated with dissolved nitrogen,but showed a significant inverse relationship to abundance of the dominant ciliates,Tintinnopsis lohmanni and Askenasia stellaris.The results provide statistical evidence that the number of P.minimum increased with increasing nitrogen,and the suppression or shortening of algal bloom may be associated with protozoan grazers,such as Tintinnopsis lohmanni,in mariculture ponds.
基金Under the auspices of National Key Technology Research and Development Program of China(No.2011BAC09B08)Special Issue of National Remote Sensing Survey and Assessment of Eco-Environment Change between 2000 and 2010(No.STSN-04-01)
文摘Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss Equation and county-level socioeconomic data to assess the changes in the ecosystem service of soil conservation between 2000 and 2010, and to analyze its spatial characteristics and driving factors in the southwestern China. The results showed that cropland in the southwestern China decreased by 3.74%, while urban land, forest, and grassland areas increased by 46.78%, 0.86%, and 1.12%, respectively. The soil conservation increased by 1.88 × 10^(11) kg, with deterioration only in some local areas. The improved and the degraded areas accounted for 6.41% and 2.44% of the total land area, respectively. Implementation of the Sloping Land Conversion Program and urbanization explained 57.80% and 23.90% of the variation in the soil conservation change, respectively, and were found to be the main factors enhancing soil conservation. The 2008 Wenchuan earthquake was one of the factors that led to the degradation of soil conservation. Furthermore, industrial adjustment, by increasing shares of Industry and Service and reducing those of Agriculture, has also promoted soil conservation. Our results quantitatively showed and emphasized the contributions to soil conservation improvement made by implementing ecological restoration programs and promoting urbanization. Consequently, these results provide basic information to improve our understanding of the effects of ecological restoration programs, and help guide future sustainable urban development and regional industrial restructuring.
基金Under the auspices of Science and Technology Service Network Initiative Project of the Chinese Academy of Sciences(No.KFJ-EW-STS-002)
文摘Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negative impacts. In this study, we propose an assessment concept framework model for indirect-direct-ecosystem service (IN-DI-ESS) driving forces within this context and method for index construction that considers the selection of a robust and parsimonious variable set. Factor analysis was integrated into two-stage data envelopment analysis (TS-DEA) to determine the driving forces and their effects on water conservation services in forest ecosystems at the provincial scale in China. The results showed the following. 1) Ten indicators with factor scores more than 0.8 were selected as the minimum data set. Four indicators comprising population density, per capita gross domestic product, irrigation efficiency, and per capita food consumption were the indirect driving factors, and six indicators comprising precipitation, farmland into forestry or pasture, forest cover, habitat area, water footprint, and wood extraction were the direct driving forces. 2) Spearman's rank correlation test was performed to compare the overall effectiveness in two periods: stage 1 and stage 2. The calculated coefficients were 0.245, 0.136, and 0.579, respectively, whereas the tabulated value was 0.562. This indicates that the driving forces obviously differed in terms of their contribution to the overall effectiveness and they caused changes in water conservation services in different stages. In terms of the variations in different driving force effects in the years 2000 and 2010, the overall, stage 1, and stage 2 variances were 0.020, 0.065, and 0.079 in 2000, respectively, and 0.018, 0.063, and 0.071 in 2010. This also indicates that heterogeneous driving force effects were obvious in the process during the same period. Identifying the driving forces that affect service changes and evaluating their efficiency have significant policy implications for the management of forest ecosystem services. Advanced effectiveness measures for weak regions could be improved in an appropriate manner. In this study, we showed that factor analysis coupled with TS-DEA based on the IN-D1-ESS framework can increase the parsimony of driving force indicators, as well as interpreting the interactions among indirect and direct driving forces with forest ecosystem water conservation services, and reducing the uncertainty related to the internal consistency during data selection.
基金grant support from the National Natural Science Foundation of China (Nos. 31130054, 31472258)the AoShan Talents Program of Qingdao National Laboratory for Marine Science and Technology (No. 2015ASTP-ES02)the Fundamental Research Funds for the Central Universities (No. 201564009)
文摘Chiton(Ischnochiton hakodadensis) is one of marine mollusks well known for its eight separate shell plates. I. hakodadensis is important, which plays a vital role in the ecosystems it inhabits. So far, the genetic studies on the chiton are scarce due in part to insufficient genomic resources available for this species. In this study, we investigated the transcriptome of the chiton foot using Illumina sequencing technology. The reads were assembled and clustered into 256461 unigenes, of which 42247 were divided into diverse functional categories by Gene Ontology(GO) annotation terms, and 17256 mapped onto 365 pathways by KEGG pathway mapping. Meanwhile, a set of differentially expressed genes(DEGs) between distal and proximal muscles were identified as the foot adhesive locomotion associated, thus were useful for our future studies. Moreover, up to 679384 high-quality single nucleotide polymorphisms(SNPs) and 19814 simple sequence repeats(SSRs) were identified in this study, which are valuable for subsequent studies on genetic diversity and variation. The transcriptomic resource obtained in this study should aid to future genetic and genomic studies of chiton.
基金Supported by the National Natural Science Foundation of China(No.30870280)a grant from the Center of Excellence in Biodiversity,King Saud University,Riyadh,Saudi Arabia
文摘Gene sequence-based genealogies of scuticociliates are different from those produced by morphological analyses.For this reason,11 representative scuticociliates and two ambiguously related genera were chosen to test the ability of combined phylogenetic analyses using both gene sequences and morphological/morphogenetic characteristics.Analyses of both the SSrRNA gene sequences and the combined datasets revealed a consistent branching pattern.While the terminal branches and the order level relationships were generally well resolved,the family level relationships remain unresolved.However,two other trees based on ITS1-5.8S-ITS2 region sequences and morphological/morphogenetic characters showed limited information,due to a lack of informative sites in these two datasets.Our data suggest,however,that the combined analysis of morphological/morphogenetic characters and gene sequences did produce some changes to the phylogenetic estimates of this group.
基金The Scientific Research Fund Project of Yunnan Education Department(2021J0592)The Yunnan University of Finance and EconomicsProgramme(2022D13)The Graduate Student Innovation Fund Project of Yunnan University of Finance and Economics(2022YUFEYC10).
文摘The exploration of ecological safety in tourism sites can provide a concrete path for sustainable tourism development in a region.Based on the“Driver-Pressure-State-Impact-Response”(DPSIR)model,we constructed an index system for the evaluation of tourism ecological security(TES)in the Silk Road Economic Belt(SREB)from 2005 to 2020.This index system was used to explore the characteristics of spatial and temporal dynamic evolution with the help of entropy weight TOPSIS method,dynamic index of TES and Markov probability transfer matrix,and a standard deviational ellipse(SDE)model and GM(1,1)model were constructed for spatial pattern analysis and prediction.The results indicate four key aspects of this system.(1)In terms of spatiotemporal evolution,the tourism ecological safety index(TESI)of the SREB increased,the TES levels of the northwestern and southwestern provinces and cities differed significantly,and the quality conditions of TES in the southwestern provinces and cities were better than in the northwest.(2)In terms of dynamic evolutionary characteristics,the speed of change at each level of the SREB was slow,but the level of TES has improved.The TES level has not shifted by leaps and bounds,and the shifts in the level type show“path dependence”and“self-locking”effects.(3)In terms of spatial and temporal distribution patterns,the spatial pattern of TES in the SREB is a“northwest-southeast”movement trend,and the spatial distribution appeared as“aggregation”from 2005 to 2020.The prediction results show that the center of gravity of TES in the SREB will shift to the southeast from 2025 to 2035,and the spatial spillover effect will be reduced.(4)In terms of driving factors,the number of star-rated hotels,and the amounts of industrial wastewater emissions,tourism foreign exchange earnings,forest coverage,and other parameters are the key factors affecting TES,and the booming tourism industry requires the interconnection and interpenetration of various factors.The results of this study can provide a reference for tourism development and ecological environmental protection in the Silk Road Economic Belt.
基金supported by National Basic Research Program of China (Grant No. 2013CB835000)National Natural Science Foundation of China (Grant Nos. 40925005, 41272036)+1 种基金the "111 Project" (Grant No. P201102007)the key project from the State Key Laboratory of Continental Dynamics, Northwest University
文摘The Cambrian explosion has long been a basic research frontier that concerns many scientific fields. Here we discuss the cause-effect links of the Cambrian explosion on the basis of first appearances of animal phyla in the fossil record, divergence time, environmental changes, Gene Regulatory Networks, and ecological feedbacks. The first appearances of phyla in the fos- sil record are obviously diachronous but relatively abrupt, concentrated in the first three stages of the Cambrian period (541- 514 Ma). The actual divergence time may be deep or shallow. Since the gene regulatory networks (GRNs) that control the de- velopment of metazoans were in place before the divergence, the establishment of GRNs is necessary but insufficient for the Cambrian explosion. Thus the Cambrian explosion required environmental triggers. Nutrient availability, oxygenation, and change of seawater composition were potential environmental triggers. The nutrient input, e.g., the phosphorus enrichment in the environment, would cause excess primary production, but it is not directly linked with diversity or disparity. Further in- crease of oxygen level and change of seawater composition during the Ediacaran-Cambrian transition were probably crucial environmental factors that caused the Cambrian explosion, but more detailed geochemical data are required. Many researchers prefer that the Cambrian explosion is an ecological phenomenon, that is, the unprecedented ecological success of ruetazoans during the Early Cambrian, but ecological effects need diverse and abundant animals. Therefore, the establishment of the eco- logical complexity among animals, and between animals and environments, is a consequence rather than a cause of the Cam- brian explosion. It is no doubt that positive ecological feedbacks could facilitate the increase of biodiversity. In a word, the Cambrian explosion happened when environmental changes crossed critical thresholds, led to the initial formation of the meta- zoan-doruinated ecosystem through a series of knock-on ecological processes, i.e., "ecological snowball" effects.
基金The National Social Science Fund of China (19BGL283)The National Natural Science Foundation of China (41301619)
文摘Ecological land can provide people with ecological products and ecological services;and it plays an important role in maintaining the health and safety of the ecosystem.With China’s rapid urbanization development,ecological land has been invaded in large quantities,and damaged seriously,even resulting in loses of its ecological function.Based on land use data from 1995 to 2015,our study explores the spatial and temporal evolution of the damage or recovery of ecological land in the Yangtze River Economic Belt(YREB).Two spatial models,geographic detector and geographic weighted regression(GWR),were employed to assess the global effects and the local effects of the driving factors for ecological land change,respectively.Our study divided the ecological land change into five types based on the degree of change as severe damage,slight damage,unchanged,slight recovery,and obvious recovery.The results show that from 1995 to 2015,the total area of ecological land in the YREB increased initially and then decreased,but the overall trend was decreasing.The total damaged area was larger than the recovered area.Arable land and woodland both showed downward trends.In terms of ecological land change over the past 20 years,the type of unchanged had the largest area,followed by slight damage and slight recovery.Our study further revealed that ecological land change was the net result of the interaction of many factors,and the explanatory power between any two driving factors was greater than that of any individual driving factor.In addition,driving factors have different impacts on ecological land change in different geographical locations.This knowledge should help land managers and policymakers to be better informed when developing pertinent land use policies at the regional and local levels.The lessons can also be extended to other regions for better management of their ecological land for sustainable use.
基金National Natural Science Foundation of China(41501192)The Strategic Priority Research Program of Chinese Academy of Sciences(XDA20040201)Key Laboratory of Earth Observation and Geospatial Information Science of NASG(201807)
文摘Farmland abandonment is a global problem and considered one of the most important areas in land use change research. Farmland abandonment research currently focuses on understanding the factors that affect farmland abandonment and developing scientific models to simulate farmland abandonment. The study reviewed the natural and political factors driving farmland abandonment and summarized the main models for farmland abandonment simulation together with their advantages and disadvantages. We discuss the main ecological effects of farmland abandonment and propose farmland abandonment research directions. The study found that:(1) the influence of labor cost change and ageing labor force on farmland abandonment needs further investigation,(2) simulation models for farmland abandonment must include the decision-making mechanism of individual farmers and focus on macro large-scale abandonment prediction models, and(3) the influence of farmland abandonment on landscape culture must be investigated in detail.
基金Acknowledgements We thank C. Long and M. Rounds for help with data collection. Thanks to Tom Getty, Genevieve Kozak, Michael Jennions, several anonymous reviewers, and the Boughman lab for helping to improve this manuscript. Research was conducted under permits from the Ministry of the Environment, BC and approval from University of Wis- consin-Madison Institutional Animal Care and Use Committee. This work was supported by the Emlen Fund from the Zoolo- gy Department of the University of Wisconsin, Madison to ACRL and the National Science Foundation to JWB.
文摘One approach to understand the importance of reproductive barriers to the speciation process is to study the break- down of barriers between formerly distinct species. One reproductive barrier, sexual isolation, reduces gene flow between species through differences in mate preferences and mating signals and is likely important for species formation and maintenance. We measure sexual isolation in two limnetic-benthic threespine stickleback species pairs (Gasterosteus spp.). One species pair main- tains strong reproductive isolation while the other species pair has recently collapsed into a hybrid swarm. We compare the strength of sexual isolation in the hybridizing pair to the currently isolated pair. We provide the first evidence that sexual isolation has been lost in the hybridizing pair and show furthermore that preferences females have for conspecific mates and the traits they use to distinguish conspecific and heterospecific males contribute to this loss. This work highlights the fragility of reproductive isolation between young species pairs and considers the role of sexual isolation in speciation [Current Zoology 59 (5): 591-603, 2013].
基金This research was funded by the Government of Newfoundland and Labrador Centre for Forest Science Innovation(CFSI)Memorial University of Newfoundland SEEDS funding to S.J.L.,E.V.W.and Y.F.W.+3 种基金Mitacs Accelerate Grant to Y.F.W.,S.J.L.and E.V.W.Canada Foundation for Innovation funding to Y.F.W.(13025)the Natural Sciences and Engineering Research Council of Canada(Discovery Grant RGPIN-2015-05799 to Y.F.W.)In-kind support was provided by Parks Canada-Terra Nova National Park and the CFSI,with thanks to Janet Feltham and Blair Adams.
文摘Aims Intraspecific variation in plant traits has important consequences for individual fitness and herbivore foraging.For plants,trait variability across spatial dimensions is well documented.However,temporal dimensions of trait variability are less well known,and may be influenced by seasonal differences in growing degree days(GDD),temperature and precipitation.Here,we aim to quantify intraspecific temporal variation in traits and the underlying drivers for four commonly occurring boreal plant species.Methods We sampled the elemental and stoichiometric traits(%C,%N,%P,C:N,C:P,N:P)of four common browse species'foliage across 2 years.Using a two-step approach,we first fitted generalized linear models(GzLM,n=24)to the species'elemental and stoichiometric traits,and tested if they varied across years.When we observed evidence for temporal variability,we fitted a second set of GzLMs(n=8)with temperature,productivity and moisture as explanatory variables.Important Findings We found no evidence of temporal variation for most of the elemental and stoichiometric traits of our four boreal plants,with two exceptions.Year was an important predictor for percent carbon across all four species(R^(2)=0.47-0.67)and for multiple elemental and stoichiometric traits in balsam fir(5/8,R2=0.29-0.67).Thus,variation in percent carbon was related to interannual differences,more so than nitrogen and phosphorus,which are limiting nutrients in the boreal forest.These results also indicate that year may explain more variation in conifers'stoichiometry than for deciduous plants due to life history differences.GDD was the most frequently occurring variable in the second round of models(8/8 times,R^(2)=0.21-0.41),suggesting that temperature is an important driver of temporal variation in these traits.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB40010300)the National Natural Science Foundation of China(41907288,41673119 and 41773140)+1 种基金the Science and Technology Foundation of Guizhou Province([2019]1317 and[2020]1Y193)the Opening Fund of the State KeyLaboratoryof Environmental Geochemistry(SKLEG2021214).
文摘Wetlands store large amounts of carbon stocks and are essential in both global carbon cycling and regional ecosystem services.Understanding the dynamics of wetland carbon exchange is crucial for assessing carbon budgets and predicting their future evolution.Although many studies have been conducted on the effects of climate change on the ecosystem carbon cycle,little is known regarding carbon emissions from the alpine wetlands in arid northwest China.In this study,we used an automatic chamber system(LI-8100A)to measure ecosystem respiration(ER)in the Bayinbuluk alpine wetland in northwest China.The ER showed a significant bimodal diurnal variation,with peak values appearing at 16:30 and 23:30(Beijing time,UTC+8).A clear seasonal pattern in ER was observed,with the highest value(19.38μmol m-2 s-l)occurring in August and the lowest value(0.11μmol m-2 s-1)occurring in late December.The annual ER in 2018 was 678 g C m-2 and respiration during the non-growing season accounted for 13%of the annual sum.Nonlinear regression revealed that soil temperature at 5 cm depth and soil water content(SwC)were the main factors controlling the seasonal variation in ER.The diurnal variation in ER was mainly controlled by air temperature and solar radiation.Higher temperature sensitivity(Qio)occurred under conditions of lower soil temperatures and medium SWC(25%≤SWC≤40%).The present study deepens our understanding of CO,emissions in alpine wetland ecosystems and helps evaluate the carbon budget in alpine wetlands in arid regions.