Background:Invasive species can threaten native diversity and alter ecosystem processes while interacting with other components of global environmental change.Invasive plants are becoming increasingly problematic and ...Background:Invasive species can threaten native diversity and alter ecosystem processes while interacting with other components of global environmental change.Invasive plants are becoming increasingly problematic and this can be stimulated by changes in the environment.However,existing studies have primarily investigated the effects of environmental change on a specific stage of plant invasion rather than the continuous invasion process.Methods:A space-for-time substitution experiment was performed to investigate how warming and nitrogen deposition affects the invasion process of a plant.Specifically,different ratios of invasive Solidago canadensis L.to native Artemisia argyi Levl.et Van were employed as a proxy to represent successive levels of invasion.A total of seven treatments were applied in the experiment:ambient(CK),N addition(+5,+12 g m^(−2)year^(−1)),warming(+1.15,+1.86℃)and their interaction(5 g N m^(−2)year^(−1)+1.15℃,12 g N m^(−2)year^(−1)+1.86℃).The growth performance and competitiveness of S.canadensis were investigated.Results:The competitiveness of Solidago canadensis decreased linearly with its invasion degree(p<0.05).Non-linear regression showed that S.canadensis invasion levels of 53%,53%,68%,55%and 58%were the critical thresholds for shifting the direction or magnitude of chlorophyll,leaf nitrogen,leaf shape index,diameter,and root/shoot ratio,respectively.Compared with the ambient treatment(CK,no warming and no N addition),the diameter,height,bio-mass and relative competitiveness of S.canadensis were each limited by warming,to a certain extent,whereas these and the above parameters were significantly increased by nitrogen deposition.The interaction of increased temperature and nitrogen deposition led to significant increases in the growth and competitiveness of S.canadensis,and this effect was detected in every stage of the invasion,throughout the invasion process.Conclusions:Environmental change might have a continuous,progressive,and augmentative effect on the phenotypic traits of S.canadensis.This study provides fairly robust evidence that environmental change promotes the invasion process of S.canadensis in general,not simply in specific stages.In the future,rather than focusing on specific stages,experimental studies should consider examining invasion on a broader scale.展开更多
The length and method of measurement of the safety-margin below the rectal cancer, being of the utmost importance for its prognosis, is still under debate.The following study was designed and done for its solution.Lig...The length and method of measurement of the safety-margin below the rectal cancer, being of the utmost importance for its prognosis, is still under debate.The following study was designed and done for its solution.Light microscopic examination was done on 83 resected rectal cancer specimens to assess the extent of intramural invasion towards the anus.By use of a ruler,the distance between the lower tumour margin and the resection line or the dentate line was measured when the specimen was:l. freshly resected,2.after fixing in 10% formalin, and 3.after being mounted in sections. The measurements were compared. By the same method,the distance between the lower tumor margin and the intended resectyion line was measured immediately before resection.It was compared with the measurement immediately after the resection.In 83 rectal cancer specimens, the extent of intramural infiltration toward the anus was:≤0.5 cm in 75 cases (90.4%).≥l cm in 2 cases which showed highly malignant carcinomas.These 2 cases, however,should not have been indicated for anus-saving resection.In 46 fresh specimens,the tumor-resection line distances gave an average of 2.7 cm.After fixing in 10% formalin, they became shortened by 0.7 cm. And, mouting in sections further shortened them by another 0.5 cm,giving a total shortening of l.2 cm.The tumor-resection line distance in 7 of the 11 fresh specimens resected by the Dixon's operation was shortened,though never more than o.5 cm immediately the operation.In performin ganus-saving resection for the low rectal cancer, after full isolation the rectum and stretching it slightly,≥3 cm of the rectum distal to the lower tumor margin should be resected.A safety margin of more than 2.5 cm is necessary in the fresh specimen.If formalin fixed specimen is measured, the safety margin should be ≥2 cm.展开更多
Native plant communities are commonly invaded by invasive plants to different degrees.However,the relative contribution of the invasive plant abundance vs.phylogenetic evenness to the responses of wetland communities ...Native plant communities are commonly invaded by invasive plants to different degrees.However,the relative contribution of the invasive plant abundance vs.phylogenetic evenness to the responses of wetland communities to different degrees of invasion is still unclear.In addition,whether such contribution varies with environmental conditions such as flooding is also unclear.To address these questions,we chose Alternanthera philoxeroides as the invasive plant,and set up four invasive degrees by changing the community species composition under both flooding and non-flooding conditions.The relative abundance of A.philoxeroides and phylogenetic evenness changed simultaneously with the change in the community invasion degree.The invasion degree significantly affected the individual biomass of A.philoxeroides and some native species.Variation partitioning showed that the relative abundance of A.philoxeroides contributed more to variation in community indicators than phylogenetic evenness,regardless of flooding.Spearman rank correlation test showed that the relative abundance of A.philoxeroides was negatively correlated with the individual biomass of A.philoxeroides and some native species,while the phylogenetic evenness was positively correlated with only a few native species.And their correlation strength and significance were all affected by specific species and flooded environment.In conclusion,our results suggest that the relative abundance of A.philoxeroides can more effectively explain the wetland community response to different invasion degrees than phylogenetic evenness,regardless of flooding.展开更多
Longhorn beetles are among the most important groups of invasive forest in-sects worldwide.In parallel,they represent one of the most well-studied insect groups interms of chemical ecology.Longhorn beetle aggregation-...Longhorn beetles are among the most important groups of invasive forest in-sects worldwide.In parallel,they represent one of the most well-studied insect groups interms of chemical ecology.Longhorn beetle aggregation-sex pheromones are commonlyused as trap lures for specific and generic surveillance programs at points of entry andmay play a key role in determining the success or failure of exotic species establishment.An exotic species might be more likely to establish in a novel habitat if it relies on apheromone channel that is different to that of native species active at the same time of yearand day,allowing for unhindered mate location(i.e.,pheromone-free space hypothesis).Inthis study,we first tested the attractiveness of single pheromone components(i.e.,racemic3-hydroxyhexan-2-one,racemic 3-hydroxyoctan-2-one,and syn-2,3-hexanediol),and theirbinary and tertiary combinations,to native and exotic longhorn beetle species in Canadaand ltaly.Second,we exploited trap catches to determine their seasonal flight activity.Third,we used pheromone-baited"timer traps"to determine longhorn beetle daily flightactivity.The response to single pheromones and their combinations was mostly speciesspecific but the combination of more than one pheromone component allowed catch ofmultiple species simultancously in ltaly.The response of the exotic species to pheromonecomponents,coupled with results on seasonal and daily flight activity,provided partialsupport for the pheromone-free space hypothesis.This study aids in the understanding oflonghorn beetle chemical ecology and confirms that pheromones can play a key role inlonghorn beetle invasions.展开更多
基金supported by the National Natural Science Foundation of China(32071521,32271587,32201297,31770446)the Carbon Peak and Carbon Neutrality Technology Innovation Foundation of Jiangsu Province(BK20220030)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20211321)the Jiangsu Planned Projects for Postdoctoral Research Funds(2021K384C)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)and the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment。
文摘Background:Invasive species can threaten native diversity and alter ecosystem processes while interacting with other components of global environmental change.Invasive plants are becoming increasingly problematic and this can be stimulated by changes in the environment.However,existing studies have primarily investigated the effects of environmental change on a specific stage of plant invasion rather than the continuous invasion process.Methods:A space-for-time substitution experiment was performed to investigate how warming and nitrogen deposition affects the invasion process of a plant.Specifically,different ratios of invasive Solidago canadensis L.to native Artemisia argyi Levl.et Van were employed as a proxy to represent successive levels of invasion.A total of seven treatments were applied in the experiment:ambient(CK),N addition(+5,+12 g m^(−2)year^(−1)),warming(+1.15,+1.86℃)and their interaction(5 g N m^(−2)year^(−1)+1.15℃,12 g N m^(−2)year^(−1)+1.86℃).The growth performance and competitiveness of S.canadensis were investigated.Results:The competitiveness of Solidago canadensis decreased linearly with its invasion degree(p<0.05).Non-linear regression showed that S.canadensis invasion levels of 53%,53%,68%,55%and 58%were the critical thresholds for shifting the direction or magnitude of chlorophyll,leaf nitrogen,leaf shape index,diameter,and root/shoot ratio,respectively.Compared with the ambient treatment(CK,no warming and no N addition),the diameter,height,bio-mass and relative competitiveness of S.canadensis were each limited by warming,to a certain extent,whereas these and the above parameters were significantly increased by nitrogen deposition.The interaction of increased temperature and nitrogen deposition led to significant increases in the growth and competitiveness of S.canadensis,and this effect was detected in every stage of the invasion,throughout the invasion process.Conclusions:Environmental change might have a continuous,progressive,and augmentative effect on the phenotypic traits of S.canadensis.This study provides fairly robust evidence that environmental change promotes the invasion process of S.canadensis in general,not simply in specific stages.In the future,rather than focusing on specific stages,experimental studies should consider examining invasion on a broader scale.
文摘The length and method of measurement of the safety-margin below the rectal cancer, being of the utmost importance for its prognosis, is still under debate.The following study was designed and done for its solution.Light microscopic examination was done on 83 resected rectal cancer specimens to assess the extent of intramural invasion towards the anus.By use of a ruler,the distance between the lower tumour margin and the resection line or the dentate line was measured when the specimen was:l. freshly resected,2.after fixing in 10% formalin, and 3.after being mounted in sections. The measurements were compared. By the same method,the distance between the lower tumor margin and the intended resectyion line was measured immediately before resection.It was compared with the measurement immediately after the resection.In 83 rectal cancer specimens, the extent of intramural infiltration toward the anus was:≤0.5 cm in 75 cases (90.4%).≥l cm in 2 cases which showed highly malignant carcinomas.These 2 cases, however,should not have been indicated for anus-saving resection.In 46 fresh specimens,the tumor-resection line distances gave an average of 2.7 cm.After fixing in 10% formalin, they became shortened by 0.7 cm. And, mouting in sections further shortened them by another 0.5 cm,giving a total shortening of l.2 cm.The tumor-resection line distance in 7 of the 11 fresh specimens resected by the Dixon's operation was shortened,though never more than o.5 cm immediately the operation.In performin ganus-saving resection for the low rectal cancer, after full isolation the rectum and stretching it slightly,≥3 cm of the rectum distal to the lower tumor margin should be resected.A safety margin of more than 2.5 cm is necessary in the fresh specimen.If formalin fixed specimen is measured, the safety margin should be ≥2 cm.
基金supported by the Fundamental Research Funds for the Central Universities(2015ZCQ-BH-01)the National Key Research and Development Program(2016YFC1201100)the China Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07602-004-003).
文摘Native plant communities are commonly invaded by invasive plants to different degrees.However,the relative contribution of the invasive plant abundance vs.phylogenetic evenness to the responses of wetland communities to different degrees of invasion is still unclear.In addition,whether such contribution varies with environmental conditions such as flooding is also unclear.To address these questions,we chose Alternanthera philoxeroides as the invasive plant,and set up four invasive degrees by changing the community species composition under both flooding and non-flooding conditions.The relative abundance of A.philoxeroides and phylogenetic evenness changed simultaneously with the change in the community invasion degree.The invasion degree significantly affected the individual biomass of A.philoxeroides and some native species.Variation partitioning showed that the relative abundance of A.philoxeroides contributed more to variation in community indicators than phylogenetic evenness,regardless of flooding.Spearman rank correlation test showed that the relative abundance of A.philoxeroides was negatively correlated with the individual biomass of A.philoxeroides and some native species,while the phylogenetic evenness was positively correlated with only a few native species.And their correlation strength and significance were all affected by specific species and flooded environment.In conclusion,our results suggest that the relative abundance of A.philoxeroides can more effectively explain the wetland community response to different invasion degrees than phylogenetic evenness,regardless of flooding.
基金We thank Giovanna Squaquara,Martina Bon,Filippo Rigodanza,Jacopo Richard,Cory Hughes and Kate Van Rooyen for technical assistance in the field and laboratoryChantelle Kostanowicz,Vincent Webster,and Reginald Webster for expertise in beetle species identification+2 种基金Joe Francese and Troy Kimoto for advice“Veneto Agricoltura”for allowing us to carry out the trapping experiment at Bosco Nordiothree anonymous reviewers for their comments on an earlier draft of this manuscript.In addition,we thank Natural Resources Canada,Canadian Forest Service,United States Department of Agriculture,Animal and Plant Health Inspection Service(grant 15-8130-0395-CA and 17-8130-0395-CA)and the University of Padova for financial support(DOR).
文摘Longhorn beetles are among the most important groups of invasive forest in-sects worldwide.In parallel,they represent one of the most well-studied insect groups interms of chemical ecology.Longhorn beetle aggregation-sex pheromones are commonlyused as trap lures for specific and generic surveillance programs at points of entry andmay play a key role in determining the success or failure of exotic species establishment.An exotic species might be more likely to establish in a novel habitat if it relies on apheromone channel that is different to that of native species active at the same time of yearand day,allowing for unhindered mate location(i.e.,pheromone-free space hypothesis).Inthis study,we first tested the attractiveness of single pheromone components(i.e.,racemic3-hydroxyhexan-2-one,racemic 3-hydroxyoctan-2-one,and syn-2,3-hexanediol),and theirbinary and tertiary combinations,to native and exotic longhorn beetle species in Canadaand ltaly.Second,we exploited trap catches to determine their seasonal flight activity.Third,we used pheromone-baited"timer traps"to determine longhorn beetle daily flightactivity.The response to single pheromones and their combinations was mostly speciesspecific but the combination of more than one pheromone component allowed catch ofmultiple species simultancously in ltaly.The response of the exotic species to pheromonecomponents,coupled with results on seasonal and daily flight activity,provided partialsupport for the pheromone-free space hypothesis.This study aids in the understanding oflonghorn beetle chemical ecology and confirms that pheromones can play a key role inlonghorn beetle invasions.
