We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby R...We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary.展开更多
Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability.Fertilization and...Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability.Fertilization and control of understory vegetation that competes with seedlings may be of help in ameliorating soil physical and chemical properties,resulting in better seedling growth and reclamation success.However,the amount of nutrients understory vegetation absorbs in this ecological process has been rarely studied.Thus,we aimed to investigate the effect of soil amendment on biomass production and nutrient uptake by weeds in the nutrient-poor reclaimed area.We applied three levels of torrefied wood chip(TWC;0,2.5,and 5 Mg ha^(−1))and two levels of vermicompost(VC;0 and 2.7 Mg ha^(−1))as soil physical improvements and organic soil amendments in reclaimed land in the Republic of Korea,with Populus euramericana used as the crop tree.Results:TWC did not influence weed biomass,but 2.7 Mg ha^(−1) VC significantly increased weed biomass by 21%compared to 0 Mg ha^(−1) VC treatments.Nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),magnesium(Mg),and sodium(Na)concentrations in weeds were the highest in control,but there was no statistical difference among treatments.However,VC treatment did marginally increase nutrient uptake in weeds,especially P,K,Ca,and Na.No treatments influenced crop tree height.Conclusion:We conclude that VC can be used as an organic source of nutrients in reclaimed soil and that weed management is necessary to increase treatment effects on crop trees in this salt-affected reclaimed land.展开更多
文摘We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary.
基金This study was funded by'R&D Program for Forest Science Technology(Project No.2018112D10-1920-BB01)'provided by Korea Forest Service(Korea Forestry Promotion Insttitute)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2018R1D1A3B07045079).
文摘Background:In reclaimed land,the growth environment for plants may be unfavorable and the initial establishment and growth of seedlings could be limited because of low nutrient and water availability.Fertilization and control of understory vegetation that competes with seedlings may be of help in ameliorating soil physical and chemical properties,resulting in better seedling growth and reclamation success.However,the amount of nutrients understory vegetation absorbs in this ecological process has been rarely studied.Thus,we aimed to investigate the effect of soil amendment on biomass production and nutrient uptake by weeds in the nutrient-poor reclaimed area.We applied three levels of torrefied wood chip(TWC;0,2.5,and 5 Mg ha^(−1))and two levels of vermicompost(VC;0 and 2.7 Mg ha^(−1))as soil physical improvements and organic soil amendments in reclaimed land in the Republic of Korea,with Populus euramericana used as the crop tree.Results:TWC did not influence weed biomass,but 2.7 Mg ha^(−1) VC significantly increased weed biomass by 21%compared to 0 Mg ha^(−1) VC treatments.Nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),magnesium(Mg),and sodium(Na)concentrations in weeds were the highest in control,but there was no statistical difference among treatments.However,VC treatment did marginally increase nutrient uptake in weeds,especially P,K,Ca,and Na.No treatments influenced crop tree height.Conclusion:We conclude that VC can be used as an organic source of nutrients in reclaimed soil and that weed management is necessary to increase treatment effects on crop trees in this salt-affected reclaimed land.
