Litter decomposition is key to ecosystem carbon(C)and nutrient cycling,but this process is anticipated to weaken due to projected more extensive and prolonged drought.Yet how litter quality and decomposer community co...Litter decomposition is key to ecosystem carbon(C)and nutrient cycling,but this process is anticipated to weaken due to projected more extensive and prolonged drought.Yet how litter quality and decomposer community complexity regulate decomposition in response to drought is less understood.Here,in a five-year manipulative drought experiment in a Masson pine forest,leaf litter from four subtropical tree species(Quercus griffthii Hook.f.&Thomson ex Miq.,Acacia mangium Willd.,Pinus massoniana Lamb.,Castanopsis hystrix Miq.)representing different qualities was decomposed for 350 d in litterbags of three different mesh sizes(i.e.,0.05,1,and 5 mm),respectively,under natural conditions and a 50%throughfall rain exclusion treatment.Litterbags of increasing mesh sizes discriminate decomposer communities(i.e.,microorganisms,microorganisms and mesofauna,microorganisms and meso-and macrofauna)that access the litter and represent an increasing complexity.The amount of litter C and nitrogen(N)loss,and changes in their ratio(C/N_(loss)),as well as small and medium-sized decomposers including microorganisms,nematodes,and arthropods,were investigated.We found that drought did not affect C and N loss but decreased C/N_(loss)(i.e.,decomposer N use efficiency)of leaf litter irrespective of litter quality and decomposer complexity.However,changes in the C/N_(loss)and the drought effect on C loss were both dependent on litter quality,while drought and decomposer complexity interactively affected litter C and N loss.Increasing decomposer community complexity enhanced litter decomposition and allowing additional access of meso-and macro-fauna to litterbags mitigated the negative drought effect on the microbial-driven decomposition.Furthermore,both the increased diversity and altered trophic structure of nematode due to drought contributed to the mitigation effects via cascading interactions.Our results show that litter quality and soil decomposer community complexity co-drive the effect of drought on litter decomposition.This experimental finding provides a new insight into the mechanisms controlling forest floor C and nutrient cycling under future global change scenarios.展开更多
Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be co...Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be controlled by reducing the amount of fertilizer applied,but pollution caused by soil and water erosion in hilly areas can only be controlled by conservation forests.The catchment area around Fushi Reservoir was selected as a test site and mechanisms of N loss from a vertical spatial perspective through field observations were determined.The main N losses occurred from June to September,accounting for 85.9-95.9%of the annual loss,with the losses in June and July accounting for 46.0%of the total,and in August and September for 41.9%.The N leakage from the water source area was effectively reduced by 38.2%through the optimization of the stand structure of the conservation forests.Establishing well-structured forests for water conservation is crucial to ensure the security of drinking water.This preliminary research lays the foundation for revealing then loss mechanisms in water source areas and improving the control of non-point source pollution in these areas.展开更多
基金jointly funded by the National Natural Science Foundation of China(No.31930078)the National Key R&D Program of China(No.2021YFD2200405)+3 种基金Science and Technology Cooperation Projects between governments of China and the European Union(No.2023YFE0105100)the Fundamental Research Funds for ICBR(No.1632021023)Sanya Research Base of ICBR(No.1630032023002)the Scientific and Technological Innovation Team for Qinghai-Tibetan Plateau Research in Southwest Minzu University(No.2024CXTD10)。
文摘Litter decomposition is key to ecosystem carbon(C)and nutrient cycling,but this process is anticipated to weaken due to projected more extensive and prolonged drought.Yet how litter quality and decomposer community complexity regulate decomposition in response to drought is less understood.Here,in a five-year manipulative drought experiment in a Masson pine forest,leaf litter from four subtropical tree species(Quercus griffthii Hook.f.&Thomson ex Miq.,Acacia mangium Willd.,Pinus massoniana Lamb.,Castanopsis hystrix Miq.)representing different qualities was decomposed for 350 d in litterbags of three different mesh sizes(i.e.,0.05,1,and 5 mm),respectively,under natural conditions and a 50%throughfall rain exclusion treatment.Litterbags of increasing mesh sizes discriminate decomposer communities(i.e.,microorganisms,microorganisms and mesofauna,microorganisms and meso-and macrofauna)that access the litter and represent an increasing complexity.The amount of litter C and nitrogen(N)loss,and changes in their ratio(C/N_(loss)),as well as small and medium-sized decomposers including microorganisms,nematodes,and arthropods,were investigated.We found that drought did not affect C and N loss but decreased C/N_(loss)(i.e.,decomposer N use efficiency)of leaf litter irrespective of litter quality and decomposer complexity.However,changes in the C/N_(loss)and the drought effect on C loss were both dependent on litter quality,while drought and decomposer complexity interactively affected litter C and N loss.Increasing decomposer community complexity enhanced litter decomposition and allowing additional access of meso-and macro-fauna to litterbags mitigated the negative drought effect on the microbial-driven decomposition.Furthermore,both the increased diversity and altered trophic structure of nematode due to drought contributed to the mitigation effects via cascading interactions.Our results show that litter quality and soil decomposer community complexity co-drive the effect of drought on litter decomposition.This experimental finding provides a new insight into the mechanisms controlling forest floor C and nutrient cycling under future global change scenarios.
基金supported by Zhejiang A&F University(2022LFR083)Key R&D Program of Zhejiang Province(2021C02038)the International Centre for Bamboo and Rattan(1632021006)。
文摘Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be controlled by reducing the amount of fertilizer applied,but pollution caused by soil and water erosion in hilly areas can only be controlled by conservation forests.The catchment area around Fushi Reservoir was selected as a test site and mechanisms of N loss from a vertical spatial perspective through field observations were determined.The main N losses occurred from June to September,accounting for 85.9-95.9%of the annual loss,with the losses in June and July accounting for 46.0%of the total,and in August and September for 41.9%.The N leakage from the water source area was effectively reduced by 38.2%through the optimization of the stand structure of the conservation forests.Establishing well-structured forests for water conservation is crucial to ensure the security of drinking water.This preliminary research lays the foundation for revealing then loss mechanisms in water source areas and improving the control of non-point source pollution in these areas.
