Based on the sample data of the listed firms on the A stock market, we analyze how the system of independent directors influence the earning conservatism from 4 dimensions designed to measure the monitoring power of t...Based on the sample data of the listed firms on the A stock market, we analyze how the system of independent directors influence the earning conservatism from 4 dimensions designed to measure the monitoring power of these independent directors： Percentage within BDs, professional capacities, stimulation and work conditions. From the empirical results, we conclude that the more powerful of the independent directors, the better the accounting conservatism, and that their positive impact increases along with the improvement on corporate governance, meanwhile the work conditions plays the most important role, and then are the percentage within BDs and their professional capacities, the stimulation and personal reputation appear the least importance.展开更多
According to the related data of A-share listed companies in 2009-2013,through extension model based on Basu＇s surplus - the stock return rate model ,this paper studies that the debt maturity structure influences on ...According to the related data of A-share listed companies in 2009-2013,through extension model based on Basu＇s surplus - the stock return rate model ,this paper studies that the debt maturity structure influences on accounting conservatism. The empirical study finds that the amount of debt affects significantly the prudence,that is,the greater the amount of the debt contract con- cluded, the stronger role of accounting conservatism is ; Debt maturity have significant relationship with accounting conservatism. For the shorter debt maturity, the enterprise is easier to choose more prudent accounting policy, and when the period is longer, accounting conservatism is relatively weaker.展开更多
This study seeks to examine the influence of board skill, multiple directorships （BSHIP）, and tenure of independent directors on accounting conservatism, as measured by asymmetric timeliness and accrual-based conser...This study seeks to examine the influence of board skill, multiple directorships （BSHIP）, and tenure of independent directors on accounting conservatism, as measured by asymmetric timeliness and accrual-based conservatism （CONACCR）. Fixed-effect regression models were constructed on a sample of 2016 firm-year observations for asymmetric timeliness model and 2033 firm-year observations for CONACCR model, which covered from 2001 to 2007. The findings show that the degree of financial expertise on the board is positively associated with the recognition of bad news which is relative to good news into earnings. BSHIP appears to have no effect on conservatism. Independent directors who have longer tenure in the board of the firms are slower in recognizing bad news which is relative to good news into earnings. The study provides empirical evidence on the effectiveness of the board of directors, which will be an interest to the practitioner or regulators in reviewing the corporate governance regulations.展开更多
This study aims to evaluate the level of accounting conservatism when preparing financial statements by companies listed in Kuwait Stock Exchange （KSE）. In addition, the study examines the factors that affect the le...This study aims to evaluate the level of accounting conservatism when preparing financial statements by companies listed in Kuwait Stock Exchange （KSE）. In addition, the study examines the factors that affect the level of accounting conservatism in those companies with regard to company sizes, debt contracts, and the type of sector the company belongs to. To achieve these goals, the Basu （1997） model was used to measure conservatism level and the factors influencing it. The sample of the study comprises of 225 companies listed in KSE. Findings of the study showed that the KSE succeeded in forcing Kuwait companies to present a reasonable level of accounting conservatism. The study also found out that the financial statements of small companies were conservative, while those of the big ones were not. In addition, the debt contracts left an impact upon financial reports of accounting conservatism. Thus, companies with lower debts were more conservative than those of higher ones. Moreover, the financial statements of the financial sector in KSE were the most conservative.展开更多
＂Conservatism＂ is a widely accepted accounting convention in the industrialized world, but it has long been slated and prohibited under the orthodox ideological influences. To date, the conservatism convention has n...＂Conservatism＂ is a widely accepted accounting convention in the industrialized world, but it has long been slated and prohibited under the orthodox ideological influences. To date, the conservatism convention has not been fully adopted or implemented although the governments have made substantial efforts to reform its accounting system to bridge the gaps between the accounting practices in recent years. The study findings will facilitate a proper assessment of the future development of accounting standards and practices.展开更多
Although accounting conservatism affects accounting practice for a long time,the attack on it has not stopped.Recently,accounting conser-vatism again gets into an embarrassing situation for the substantial introductio...Although accounting conservatism affects accounting practice for a long time,the attack on it has not stopped.Recently,accounting conser-vatism again gets into an embarrassing situation for the substantial introduction of fair value measurement.Is it necessary for accounting conservatism in Chi-na?On the basis of the review of the concept development of accounting conservatism,the paper further investigates the debt contract interpretation and com-pensation contract interpretation,economic consequences.Combining with the specific situation of our country,the paper argues it is necessary for accounting conservatism to exist in China.展开更多
The philosophical debate between“radicalism”and“conservatism”in emerging human enhancement technologies(HET)has never ceased.Although their theoreti-cal claims seem to be distinct from each other,they actually sha...The philosophical debate between“radicalism”and“conservatism”in emerging human enhancement technologies(HET)has never ceased.Although their theoreti-cal claims seem to be distinct from each other,they actually share certain common-alities,which are mainly manifested in three aspects:first,they both hold certain illusions about emerging HET;second,they both reflect the loss of human subjec-tivity in the debate;and third,they both leave the premise of their propositions in suspense.Based on the reflection and grasp of these commonalities,we can grasp the possible boundaries of the dissolution of the two oppositions:let HET be“where it is in,”reconfigure anthropocentrism,suspend metaphysical myths,and turn to the“reality of human beings.”展开更多
The ecological and evolutionary mechanisms underlying montane biodiversity patterns remain unresolved.To understand which factors determined community assembly rules in mountains,biogeographic affinity that represents...The ecological and evolutionary mechanisms underlying montane biodiversity patterns remain unresolved.To understand which factors determined community assembly rules in mountains,biogeographic affinity that represents the biogeographic and evolutionary history of species should incorporate with current environments.We aim to address two following questions:1)How does plant taxonomic and phylogenetic diversity with disparate biogeographic affinitiesvary along the subtropical elevational gradient?2)How do biogeographic affinityand environmental drivers regulate the community assembly?We collected woody plant survey data of 32 forest plots in a subtropical mountain of Mt.Guanshan with typical transitional characteristics,including 250 woody plant species belonging to 56 families and 118 genera.We estimated the effects of biogeographic affinity,climate and soil properties on taxonomic and phylogenetic diversity of plant communities employing linear regression and structural equation models.We found that the richness of temperate-affiliated species increased with elevations,but the evenness decreased,while tropical-affiliatedspecies had no significantpatterns.Winter temperature directly or indirectly via biogeographic affinityshaped the assemblage of woody plant communities along elevations.Biogeographic affinityaffected what kind of species could colonize higher elevations while local environment determined their fitnessto adapt.These results suggest that biogeographic affinityand local environment jointly lead to the dominance of temperate-affiliated species at higher elevations and shape the diversity of woody plant communities along elevational gradients.Our findingshighlight the legacy effect of biogeographic affinityon the composition and structure of subtropical montane forests.展开更多
In the last few years,scholars have continued to refine the understanding of conservatism through cultural psychology.The application of Symbolic Action Theory,particularly Ernst Boesch’s framework,remains central to...In the last few years,scholars have continued to refine the understanding of conservatism through cultural psychology.The application of Symbolic Action Theory,particularly Ernst Boesch’s framework,remains central to discussions,illustrating how conservatism is not merely a political stance but a dynamic system of behaviors that reinforces societal values through symbolic actions(Kölbl,2020).Additionally,recent studies have highlighted the interaction between cultural conservatism and collective identity,with particular focus on how conservatism can manifest in diverse cultural settings(Yilmaz&Alper,2019).Research also underscores the relevance of symbolic politics in shaping both individual attitudes and broader political actions,contributing to the understanding of how symbolic meanings sustain social conservatism in different cultural contexts(Chin&Levey,2022).展开更多
Predicting whether alien species will invade a native community is a key challenge in invasion ecology.One factor that may help predict invasion success is phylogenetic relatedness.Darwin proposed that closely related...Predicting whether alien species will invade a native community is a key challenge in invasion ecology.One factor that may help predict invasion success is phylogenetic relatedness.Darwin proposed that closely related species tend to share similar niches,although this relationship may be influenced by various ecological and evolutionary factors.To test this,we classified alien Asteraceae species in China into three categories based on their invasion status and the extent of ecological damage:introduced,naturalized,and invasive.We then compared the genetic relationships and niche overlap between alien and native Asteraceae species.We found that invasive Asteraceae species are more closely related to native Asteraceae species than are introduced and naturalized species.However,alien Asteraceae species(including introduced,naturalized,and invasive species)exhibited relatively low niche overlap with native Asteraceae species.These findings suggest that the main premise underlying Darwin’s naturalization conundrum,namely,the universality of phylogenetic niche conservatism,may not hold true.Instead,our findings indicate that alien species are more likely to invade successfully when they are more closely related to native plants,exhibit less niche overlap,and maintain conservative niches during the invasion process.These findings provide new insights into the mechanisms of alien plant invasions,highlight the relationship between alien species invasions and native community vulnerability,and offer important insights into the development of effective biological invasion management strategies.展开更多
A principal-agent relationship exists among creditors,shareholders and management,and information asymmetry among them leads to asymmetric loss functions,which induces conservative accounting.This paper investigates t...A principal-agent relationship exists among creditors,shareholders and management,and information asymmetry among them leads to asymmetric loss functions,which induces conservative accounting.This paper investigates the determinants of accounting conservatism using accrual-based measures and data from 2001 to 2006 in China.We find that a higher degree of leverage,lower level of control of ultimate shareholders and lower level of management ownership lead to more conservative financial reporting.We also find that political concerns and pressures among state-owned enterprises are greater than those among non-state owned enterprises,which leads to more conservative financial reporting among the former.However,a decrease in such concerns leads to a decrease in accounting conservatism.Overall,we find that among the determinants of conservatism in China,debt is the most important,followed by ownership,and that board has little influence.展开更多
Based on signaling and gender discrimination theory, we examine whether chief financial officer(CFO) gender matters to bank–firm relationships and the designing of collateral clauses in bank loan contracting, and exp...Based on signaling and gender discrimination theory, we examine whether chief financial officer(CFO) gender matters to bank–firm relationships and the designing of collateral clauses in bank loan contracting, and explore the potential path of influence. Data taken from Chinese listed companies between2009 and 2012 indicate that(1) female-CFO-led firms are less likely to obtain credit loans than male-CFO-led firms;(2) female-CFO-led borrowers are more likely to be required to provide collateral for loans than male-CFO-led borrowers; and(3) banks are more inclined to claim mortgaging collateral when lending to female-CFO-led firms and prefer to guarantee collateral when lending to male-CFO-led firms. Female-CFO-led borrowers seem to be granted more unfavorable loan terms than male-CFO-led borrowers, supporting the hypothesis that female CFOs experience credit discrimination. Further analysis reveals that regional financial development helps to alleviate lending discrimination against female CFOs. Furthermore, female CFOs in SOEs are less likely than their non-SOE counterparts to experience gender discrimination in the credit market.展开更多
This paper investigates the factors affecting the conservatism of accounting reports at the market-level and firm-level. At the market-level, law and institutional factors explain conservatism, while at the firm-level...This paper investigates the factors affecting the conservatism of accounting reports at the market-level and firm-level. At the market-level, law and institutional factors explain conservatism, while at the firm-level contracting is the driver. We predict and observe that while both levels jointly affect conservatism, it is firm-level factors that play a dominant role. The conclusion suggests that it is more effective to improve the quality of accounting reports by motivating the firm's own demand rather than through listing in a developed capital market.展开更多
Using a sample of A-share listed firms in China during the 2003–2012 period,this paper investigates the effect of accounting conservatism on trade credit,taking changes in monetary policy into account.We find that co...Using a sample of A-share listed firms in China during the 2003–2012 period,this paper investigates the effect of accounting conservatism on trade credit,taking changes in monetary policy into account.We find that corporations with higher accounting conservatism obtain more trade credit and that accounting conservatism has a greater influence on trade credit under tight monetary policy.Furthermore,the backgrounds of the supplier and customer influence the positive relationship between accounting conservatism and trade credit.This influence is more evident when a company is privately owned and has greater market power,and less evident when the supplier or customer is the controlling shareholder.展开更多
Species range expansions are crucial for understanding niche formation and the interaction with the environment.Here,we studied the bumblebee Bombus haematurus Kriechbaumer,1870,a species historically distributed from...Species range expansions are crucial for understanding niche formation and the interaction with the environment.Here,we studied the bumblebee Bombus haematurus Kriechbaumer,1870,a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Europe without human-mediated dispersal(i.e.,it is a natural spread).After updating the global distribution of this species,we investigated if niche shifts took place during this range expansion between newly colonized and historical areas.In addition,we have explored which climatic factors may have favored the natural range expansion of the species.Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018,a natural expansion over an area that equals 20%of the historical distribution.In addition,this bumblebee performs generalism in flower visitation and it occurs in different habitats,although a preference for forested areas clearly emerges.The land-use associated with the species in the colonized areas is similar to the historical distribution,indicating that no major niche shifts occurred during the spread.Furthermore,in recently colonized localities,the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases.These findings document a case of natural range expansion due to environmental change rather than due to niche shifts,and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.展开更多
文摘Based on the sample data of the listed firms on the A stock market, we analyze how the system of independent directors influence the earning conservatism from 4 dimensions designed to measure the monitoring power of these independent directors： Percentage within BDs, professional capacities, stimulation and work conditions. From the empirical results, we conclude that the more powerful of the independent directors, the better the accounting conservatism, and that their positive impact increases along with the improvement on corporate governance, meanwhile the work conditions plays the most important role, and then are the percentage within BDs and their professional capacities, the stimulation and personal reputation appear the least importance.
文摘According to the related data of A-share listed companies in 2009-2013,through extension model based on Basu＇s surplus - the stock return rate model ,this paper studies that the debt maturity structure influences on accounting conservatism. The empirical study finds that the amount of debt affects significantly the prudence,that is,the greater the amount of the debt contract con- cluded, the stronger role of accounting conservatism is ; Debt maturity have significant relationship with accounting conservatism. For the shorter debt maturity, the enterprise is easier to choose more prudent accounting policy, and when the period is longer, accounting conservatism is relatively weaker.
文摘This study seeks to examine the influence of board skill, multiple directorships （BSHIP）, and tenure of independent directors on accounting conservatism, as measured by asymmetric timeliness and accrual-based conservatism （CONACCR）. Fixed-effect regression models were constructed on a sample of 2016 firm-year observations for asymmetric timeliness model and 2033 firm-year observations for CONACCR model, which covered from 2001 to 2007. The findings show that the degree of financial expertise on the board is positively associated with the recognition of bad news which is relative to good news into earnings. BSHIP appears to have no effect on conservatism. Independent directors who have longer tenure in the board of the firms are slower in recognizing bad news which is relative to good news into earnings. The study provides empirical evidence on the effectiveness of the board of directors, which will be an interest to the practitioner or regulators in reviewing the corporate governance regulations.
文摘This study aims to evaluate the level of accounting conservatism when preparing financial statements by companies listed in Kuwait Stock Exchange （KSE）. In addition, the study examines the factors that affect the level of accounting conservatism in those companies with regard to company sizes, debt contracts, and the type of sector the company belongs to. To achieve these goals, the Basu （1997） model was used to measure conservatism level and the factors influencing it. The sample of the study comprises of 225 companies listed in KSE. Findings of the study showed that the KSE succeeded in forcing Kuwait companies to present a reasonable level of accounting conservatism. The study also found out that the financial statements of small companies were conservative, while those of the big ones were not. In addition, the debt contracts left an impact upon financial reports of accounting conservatism. Thus, companies with lower debts were more conservative than those of higher ones. Moreover, the financial statements of the financial sector in KSE were the most conservative.
文摘＂Conservatism＂ is a widely accepted accounting convention in the industrialized world, but it has long been slated and prohibited under the orthodox ideological influences. To date, the conservatism convention has not been fully adopted or implemented although the governments have made substantial efforts to reform its accounting system to bridge the gaps between the accounting practices in recent years. The study findings will facilitate a proper assessment of the future development of accounting standards and practices.
文摘Although accounting conservatism affects accounting practice for a long time,the attack on it has not stopped.Recently,accounting conser-vatism again gets into an embarrassing situation for the substantial introduction of fair value measurement.Is it necessary for accounting conservatism in Chi-na?On the basis of the review of the concept development of accounting conservatism,the paper further investigates the debt contract interpretation and com-pensation contract interpretation,economic consequences.Combining with the specific situation of our country,the paper argues it is necessary for accounting conservatism to exist in China.
基金Hunan Provincial Natural Science Foundation:Research on Ethica Issues and Governance Strategies of Emerging Human Enhancement Technologies(Grant No.2024JJ5278).
文摘The philosophical debate between“radicalism”and“conservatism”in emerging human enhancement technologies(HET)has never ceased.Although their theoreti-cal claims seem to be distinct from each other,they actually share certain common-alities,which are mainly manifested in three aspects:first,they both hold certain illusions about emerging HET;second,they both reflect the loss of human subjec-tivity in the debate;and third,they both leave the premise of their propositions in suspense.Based on the reflection and grasp of these commonalities,we can grasp the possible boundaries of the dissolution of the two oppositions:let HET be“where it is in,”reconfigure anthropocentrism,suspend metaphysical myths,and turn to the“reality of human beings.”
基金financialsupport from the Jiangxi Natural Science Foundation(20242BAB25345)to Z.Z.the Innovation Program of Shanghai Municipal Education Commission(2023ZKZD36)to J.Z.
文摘The ecological and evolutionary mechanisms underlying montane biodiversity patterns remain unresolved.To understand which factors determined community assembly rules in mountains,biogeographic affinity that represents the biogeographic and evolutionary history of species should incorporate with current environments.We aim to address two following questions:1)How does plant taxonomic and phylogenetic diversity with disparate biogeographic affinitiesvary along the subtropical elevational gradient?2)How do biogeographic affinityand environmental drivers regulate the community assembly?We collected woody plant survey data of 32 forest plots in a subtropical mountain of Mt.Guanshan with typical transitional characteristics,including 250 woody plant species belonging to 56 families and 118 genera.We estimated the effects of biogeographic affinity,climate and soil properties on taxonomic and phylogenetic diversity of plant communities employing linear regression and structural equation models.We found that the richness of temperate-affiliated species increased with elevations,but the evenness decreased,while tropical-affiliatedspecies had no significantpatterns.Winter temperature directly or indirectly via biogeographic affinityshaped the assemblage of woody plant communities along elevations.Biogeographic affinityaffected what kind of species could colonize higher elevations while local environment determined their fitnessto adapt.These results suggest that biogeographic affinityand local environment jointly lead to the dominance of temperate-affiliated species at higher elevations and shape the diversity of woody plant communities along elevational gradients.Our findingshighlight the legacy effect of biogeographic affinityon the composition and structure of subtropical montane forests.
基金supported by the Philosophy and Social Science Research Fund of Zhejiang Province(Grant No.24ZJQN095YB)the Educational and Teaching Reform Project of HDU-ITMO Joint Institute(Grant No.SGJ2023JG007).
文摘In the last few years,scholars have continued to refine the understanding of conservatism through cultural psychology.The application of Symbolic Action Theory,particularly Ernst Boesch’s framework,remains central to discussions,illustrating how conservatism is not merely a political stance but a dynamic system of behaviors that reinforces societal values through symbolic actions(Kölbl,2020).Additionally,recent studies have highlighted the interaction between cultural conservatism and collective identity,with particular focus on how conservatism can manifest in diverse cultural settings(Yilmaz&Alper,2019).Research also underscores the relevance of symbolic politics in shaping both individual attitudes and broader political actions,contributing to the understanding of how symbolic meanings sustain social conservatism in different cultural contexts(Chin&Levey,2022).
基金supported by the National Natural Science Foundation of China(32271584 and 31600445)the Natural Science Basic Research Plan in Shaanxi Province of China(2020JM-286)+2 种基金the Fundamental Research Funds for the Central Universities(GK202103072 and GK202103073)the Key Research and Development Program of Shaanxi Province(2025SF-YBXM-514)Special Research Project in Philosophy and Social Sciences of Shaanxi Province(2022HZ1795).
文摘Predicting whether alien species will invade a native community is a key challenge in invasion ecology.One factor that may help predict invasion success is phylogenetic relatedness.Darwin proposed that closely related species tend to share similar niches,although this relationship may be influenced by various ecological and evolutionary factors.To test this,we classified alien Asteraceae species in China into three categories based on their invasion status and the extent of ecological damage:introduced,naturalized,and invasive.We then compared the genetic relationships and niche overlap between alien and native Asteraceae species.We found that invasive Asteraceae species are more closely related to native Asteraceae species than are introduced and naturalized species.However,alien Asteraceae species(including introduced,naturalized,and invasive species)exhibited relatively low niche overlap with native Asteraceae species.These findings suggest that the main premise underlying Darwin’s naturalization conundrum,namely,the universality of phylogenetic niche conservatism,may not hold true.Instead,our findings indicate that alien species are more likely to invade successfully when they are more closely related to native plants,exhibit less niche overlap,and maintain conservative niches during the invasion process.These findings provide new insights into the mechanisms of alien plant invasions,highlight the relationship between alien species invasions and native community vulnerability,and offer important insights into the development of effective biological invasion management strategies.
基金sponsored by the National Natural Science Foundation of China(grant number 70772017)
文摘A principal-agent relationship exists among creditors,shareholders and management,and information asymmetry among them leads to asymmetric loss functions,which induces conservative accounting.This paper investigates the determinants of accounting conservatism using accrual-based measures and data from 2001 to 2006 in China.We find that a higher degree of leverage,lower level of control of ultimate shareholders and lower level of management ownership lead to more conservative financial reporting.We also find that political concerns and pressures among state-owned enterprises are greater than those among non-state owned enterprises,which leads to more conservative financial reporting among the former.However,a decrease in such concerns leads to a decrease in accounting conservatism.Overall,we find that among the determinants of conservatism in China,debt is the most important,followed by ownership,and that board has little influence.
基金financial support received from the National Natural Science Foundation of China (Approval Nos. 71102063, 71572019 and 71232004)the Fundamental Research Funds for Central Universities (Approval Nos. CQDXWL-2013-Z005 and 106112015CDJSK 02XK12)
文摘Based on signaling and gender discrimination theory, we examine whether chief financial officer(CFO) gender matters to bank–firm relationships and the designing of collateral clauses in bank loan contracting, and explore the potential path of influence. Data taken from Chinese listed companies between2009 and 2012 indicate that(1) female-CFO-led firms are less likely to obtain credit loans than male-CFO-led firms;(2) female-CFO-led borrowers are more likely to be required to provide collateral for loans than male-CFO-led borrowers; and(3) banks are more inclined to claim mortgaging collateral when lending to female-CFO-led firms and prefer to guarantee collateral when lending to male-CFO-led firms. Female-CFO-led borrowers seem to be granted more unfavorable loan terms than male-CFO-led borrowers, supporting the hypothesis that female CFOs experience credit discrimination. Further analysis reveals that regional financial development helps to alleviate lending discrimination against female CFOs. Furthermore, female CFOs in SOEs are less likely than their non-SOE counterparts to experience gender discrimination in the credit market.
基金supported by Program for New Century Excellent Talents in University
文摘This paper investigates the factors affecting the conservatism of accounting reports at the market-level and firm-level. At the market-level, law and institutional factors explain conservatism, while at the firm-level contracting is the driver. We predict and observe that while both levels jointly affect conservatism, it is firm-level factors that play a dominant role. The conclusion suggests that it is more effective to improve the quality of accounting reports by motivating the firm's own demand rather than through listing in a developed capital market.
基金supported by the National Natural Science Foundation of China(Project No.71202170)The Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(Project No.CIT&TCD201504003)
文摘Using a sample of A-share listed firms in China during the 2003–2012 period,this paper investigates the effect of accounting conservatism on trade credit,taking changes in monetary policy into account.We find that corporations with higher accounting conservatism obtain more trade credit and that accounting conservatism has a greater influence on trade credit under tight monetary policy.Furthermore,the backgrounds of the supplier and customer influence the positive relationship between accounting conservatism and trade credit.This influence is more evident when a company is privately owned and has greater market power,and less evident when the supplier or customer is the controlling shareholder.
基金We warmly thank Irene Konovalova,Danilo Bevk,Paul Williams,Fred-erique Bakker,Maurizio Cornalba,Jakub Straka,and the participants at the ABIM一Alpine Bombus International Meeting for data sharing and/or for the fruitflil discus sions discus sions on Bombus haematurus.The contribution of AC was partly supported through the Project of Ministry of Education,Science and Technological Development of the Republic of Serbia(#III43001).
文摘Species range expansions are crucial for understanding niche formation and the interaction with the environment.Here,we studied the bumblebee Bombus haematurus Kriechbaumer,1870,a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Europe without human-mediated dispersal(i.e.,it is a natural spread).After updating the global distribution of this species,we investigated if niche shifts took place during this range expansion between newly colonized and historical areas.In addition,we have explored which climatic factors may have favored the natural range expansion of the species.Our results indicated that Bombus haematurus has colonized large territories in 7 European countries outside the historical area in the period from the 1980s to 2018,a natural expansion over an area that equals 20%of the historical distribution.In addition,this bumblebee performs generalism in flower visitation and it occurs in different habitats,although a preference for forested areas clearly emerges.The land-use associated with the species in the colonized areas is similar to the historical distribution,indicating that no major niche shifts occurred during the spread.Furthermore,in recently colonized localities,the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases.These findings document a case of natural range expansion due to environmental change rather than due to niche shifts,and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.
