Manglietia patungensis is an endangered species distributed aggregately in evergreen broad-leaved forest communities in Southwest China. A controlling experiment was employed to test the effects of soil type and shade...Manglietia patungensis is an endangered species distributed aggregately in evergreen broad-leaved forest communities in Southwest China. A controlling experiment was employed to test the effects of soil type and shade degree on seed germination and seedling establishment by using four soil types and three shade treatments with five replicates. Results showed that the germination rate of M. patungensis seeds was relatively low ranging from 19% to 31%. Shade degree and soil type had no significant effect on seed germination rate, but influenced germination dynamics. Both shade degree and soil type treatments significantly affected seedling survival and seedling growth. Seedling survival rate increased with increasing light density. Increased light also promoted biomass accumulation and root development of seedlings. The biomass of the seedlings under full light condition increased 72% comparing with the seedlings under 80% shade degree. Root depth, root area and cross number increased with the increase of light density. Seedlings on farmland soil survived better than that on other three kinds of soil. The seedling survival rate in the farmland soil reached 91.4%, but was reduced to 80.3%, 78.0% and 52.8% in old-field soil, sandy soil and forest soil respectively. Total biomass, aboveground biomass and root biomass of seedlings in forest soil was the highest, followed by seedlings in sandy and old-field soils respectively, and seedlings in farmland soil ranked the least. Some suggestions were finally put forward for the conservation of M. patungensis based on the research results.展开更多
Introduction:Riparian vegetation plays a crucial role in soil conservation and riverbank reinforcement.The Three Gorges hydrologic project has significantly changed the pattern of water-level fluctuation and riparian ...Introduction:Riparian vegetation plays a crucial role in soil conservation and riverbank reinforcement.The Three Gorges hydrologic project has significantly changed the pattern of water-level fluctuation and riparian environment,which significantly influenced plant community development and its effect on soil conservation and riverbank protection.Cynodon dactylon,a perennial grass with developed root system and creeping stems,has become a dominant riparian species in the Three Gorges area after the completion of the dam.We aimed to characterize how the soil-root system under the C.dactylon community responded to environmental changes and effects of the soil-root system on shallow soil conservation and riverbank reinforcement through field investigation and laboratory test.Methods:We conducted a field survey and experimental research.Quadrates of a natural C.dactylon community were set up on a riverbank along an altitude gradient.Plants were sampled randomly for the measurements of spatial structure and tensile strength of roots.Soil erosion resistance,soil scour resistance,and shear strength of sampled soil-root systems and control soil were tested in the laboratory.Results:Roots of the C.dactylon community significantly increased soil erosion resistance,soil scour resistance,and shear strength,enhancing the stability of shallow soil and riverbank.Due to water-level fluctuation,C.dactylon at lower altitudes was subjected to less time exposed to air.As a result,the soil-root systems at lower altitudes were characterized by reduced biomass with reduced capacity for soil reinforcement as measured through erosion resistance,soil scour resistance,and shear strength.The correlation analysis indicated that root biomass had a significant positive linear correlation with the enhancement of erosion resistance and scour resistance,and shear strength,respectively.Conclusions:Roots of the C.dactylon community effectively enhanced the stability of riparian shallow soil and riverbank.The fluctuation in water level caused the difference of root growth as the exposed time of plants decreases with the decrease of altitude.The difference of root structure resulted in the variation of the soil-root system in soil conservation and reinforcement.展开更多
Introduction:Soil microbial community plays a crucial role in the ecological processes of soil ecosystem.Forest species introduction often changes profoundly soil ecological processes in the forest.Larix kaempferi(Lam...Introduction:Soil microbial community plays a crucial role in the ecological processes of soil ecosystem.Forest species introduction often changes profoundly soil ecological processes in the forest.Larix kaempferi(Lam.)was introduced to China from Japan as a timber tree species in the 1960s.The activity and functional diversity of soil microorganisms in the L.kaempferi forest in Dalaoling National Forest Park in Hubei Province,China,was studied to evaluate the effects of this exotic species on the local soil ecosystems.Methods:Quadrates were set up randomly in the L.kaempferi forests cultivated in 1990 and 1996 and the surrounding Pinus armandii forest cultivated in 1990.Soil samples were collected using a soil corer at five locations along the diagonals in each quadrat.The activity and functional diversity of soil microorganisms were tested using the BIOLOG technique in laboratory.Results:The diversity,activity,and carbon utilization pattern of soil microorganism community and soil physicochemical properties were all impacted by the introduced species.The average well color development(AWCD)and Shannon’s richness index(H)of the soil microorganism community in the L.kaempferi forest decreased with the increase in forest age and were significantly lower than those in the surrounding native P.armandii forest.The carbon source utilization pattern of soil microorganism community in a 23-year-old L.kaempferi forest differed significantly from a 17-year-old L.kaempferi forest and the P.armandii forest.The introduced species also resulted in the changes of soil physicochemical properties.The organic material content,total nitrogen,available nitrogen,and total phosphorus in the soil of L.kaempferi forest were significantly lower than those in the soil of P.armandii forest.Conclusions:Introduction and long-time cultivation of L.kaempferi significantly altered the soil microbial functional diversity and activity and the soil physicochemical properties.The alteration increased with the increase of forest age.展开更多
Aims Riparian ecosystems play an important role in overall ecosystem function,including the global carbon cycle of terrestrial ecosystems,at both landscape and global scales.Yet few studies have reported in situ measu...Aims Riparian ecosystems play an important role in overall ecosystem function,including the global carbon cycle of terrestrial ecosystems,at both landscape and global scales.Yet few studies have reported in situ measurements of CO_(2) in riparian areas where flooding is a unique disturbance to carbon cycling.Methods At multiple locations across riparian zones(RZ)with different water submergences in Xiangxi Bay(XXB),we studied seasonal variations of CO_(2) exchange between this Cynodon-dominated community and the atmosphere for 2 years by using static chambers.Important Findings We found that the seasonal changes in CO_(2) fluxes were apparent and dependent on the biophysical environment.In the beginning of spring,low gross primary productivity(GPP)in lightly flooded zones(LFZ)resulted in a positive net ecosystem exchange(NEE),indicating a net CO_(2) source.With the increase in temperature,more species and vegetation abundance appeared,and the increased GPP turned the LFZ from a net CO_(2) source into a sink.This transi-tion seemed predominantly controlled by the physiological growth of vegetation.The mean NEEs,REs and the light-use efficiency(α)of the vegetation at HFZ and MFZ were significantly higher than those at LFZ and UFZ.Yet the coefficients of variation(CV)of NEE and RE at MFZ and HFZ were lower than those at LFZ and UFZ.Submergence promoted the emission and uptake of CO_(2) to the atmosphere.Elongated submergence reduced the number of spe-cies and lowered the spatial variability of the RZ,further lowering the variation of the CO_(2) exchange.展开更多
Due to questions raised regarding authorship of the article entitled“Evolutionary thinking in restoration under global environmental changes”by Chuanhua Wang,Tianhua He and Fangqing Chen,published online:February 13...Due to questions raised regarding authorship of the article entitled“Evolutionary thinking in restoration under global environmental changes”by Chuanhua Wang,Tianhua He and Fangqing Chen,published online:February 13,2013(http://jpe.oxfordjournals.org/content/early/2013/02/05/jpe.rtt005.full)in Journal of Plant Ecology(DOI:10.1093/jpe/rtt005),the editors have requested it be retracted from the journal.展开更多
文摘Manglietia patungensis is an endangered species distributed aggregately in evergreen broad-leaved forest communities in Southwest China. A controlling experiment was employed to test the effects of soil type and shade degree on seed germination and seedling establishment by using four soil types and three shade treatments with five replicates. Results showed that the germination rate of M. patungensis seeds was relatively low ranging from 19% to 31%. Shade degree and soil type had no significant effect on seed germination rate, but influenced germination dynamics. Both shade degree and soil type treatments significantly affected seedling survival and seedling growth. Seedling survival rate increased with increasing light density. Increased light also promoted biomass accumulation and root development of seedlings. The biomass of the seedlings under full light condition increased 72% comparing with the seedlings under 80% shade degree. Root depth, root area and cross number increased with the increase of light density. Seedlings on farmland soil survived better than that on other three kinds of soil. The seedling survival rate in the farmland soil reached 91.4%, but was reduced to 80.3%, 78.0% and 52.8% in old-field soil, sandy soil and forest soil respectively. Total biomass, aboveground biomass and root biomass of seedlings in forest soil was the highest, followed by seedlings in sandy and old-field soils respectively, and seedlings in farmland soil ranked the least. Some suggestions were finally put forward for the conservation of M. patungensis based on the research results.
基金by a National Key Technology R&D Program of China(2012BAC06B02-04).
文摘Introduction:Riparian vegetation plays a crucial role in soil conservation and riverbank reinforcement.The Three Gorges hydrologic project has significantly changed the pattern of water-level fluctuation and riparian environment,which significantly influenced plant community development and its effect on soil conservation and riverbank protection.Cynodon dactylon,a perennial grass with developed root system and creeping stems,has become a dominant riparian species in the Three Gorges area after the completion of the dam.We aimed to characterize how the soil-root system under the C.dactylon community responded to environmental changes and effects of the soil-root system on shallow soil conservation and riverbank reinforcement through field investigation and laboratory test.Methods:We conducted a field survey and experimental research.Quadrates of a natural C.dactylon community were set up on a riverbank along an altitude gradient.Plants were sampled randomly for the measurements of spatial structure and tensile strength of roots.Soil erosion resistance,soil scour resistance,and shear strength of sampled soil-root systems and control soil were tested in the laboratory.Results:Roots of the C.dactylon community significantly increased soil erosion resistance,soil scour resistance,and shear strength,enhancing the stability of shallow soil and riverbank.Due to water-level fluctuation,C.dactylon at lower altitudes was subjected to less time exposed to air.As a result,the soil-root systems at lower altitudes were characterized by reduced biomass with reduced capacity for soil reinforcement as measured through erosion resistance,soil scour resistance,and shear strength.The correlation analysis indicated that root biomass had a significant positive linear correlation with the enhancement of erosion resistance and scour resistance,and shear strength,respectively.Conclusions:Roots of the C.dactylon community effectively enhanced the stability of riparian shallow soil and riverbank.The fluctuation in water level caused the difference of root growth as the exposed time of plants decreases with the decrease of altitude.The difference of root structure resulted in the variation of the soil-root system in soil conservation and reinforcement.
基金by the National Natural Science Foundation of China(51379105).
文摘Introduction:Soil microbial community plays a crucial role in the ecological processes of soil ecosystem.Forest species introduction often changes profoundly soil ecological processes in the forest.Larix kaempferi(Lam.)was introduced to China from Japan as a timber tree species in the 1960s.The activity and functional diversity of soil microorganisms in the L.kaempferi forest in Dalaoling National Forest Park in Hubei Province,China,was studied to evaluate the effects of this exotic species on the local soil ecosystems.Methods:Quadrates were set up randomly in the L.kaempferi forests cultivated in 1990 and 1996 and the surrounding Pinus armandii forest cultivated in 1990.Soil samples were collected using a soil corer at five locations along the diagonals in each quadrat.The activity and functional diversity of soil microorganisms were tested using the BIOLOG technique in laboratory.Results:The diversity,activity,and carbon utilization pattern of soil microorganism community and soil physicochemical properties were all impacted by the introduced species.The average well color development(AWCD)and Shannon’s richness index(H)of the soil microorganism community in the L.kaempferi forest decreased with the increase in forest age and were significantly lower than those in the surrounding native P.armandii forest.The carbon source utilization pattern of soil microorganism community in a 23-year-old L.kaempferi forest differed significantly from a 17-year-old L.kaempferi forest and the P.armandii forest.The introduced species also resulted in the changes of soil physicochemical properties.The organic material content,total nitrogen,available nitrogen,and total phosphorus in the soil of L.kaempferi forest were significantly lower than those in the soil of P.armandii forest.Conclusions:Introduction and long-time cultivation of L.kaempferi significantly altered the soil microbial functional diversity and activity and the soil physicochemical properties.The alteration increased with the increase of forest age.
基金This research was a part of the project funded by the National Natural Science Foundation of China(NSFC)(NO.30900196 and NO.51278281)to Three Georges UniversityIt was also funded by Natural Science Foundation of Hubei Province(2015CFC834)+1 种基金Provincial Department of Education Scientific research projects(Q20151209)the Key Laboratory of Aquatic Botany and Watershed Ecology at the Chinese Academy of Sciences,and Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,Ministry of Education(KF2016-03).
文摘Aims Riparian ecosystems play an important role in overall ecosystem function,including the global carbon cycle of terrestrial ecosystems,at both landscape and global scales.Yet few studies have reported in situ measurements of CO_(2) in riparian areas where flooding is a unique disturbance to carbon cycling.Methods At multiple locations across riparian zones(RZ)with different water submergences in Xiangxi Bay(XXB),we studied seasonal variations of CO_(2) exchange between this Cynodon-dominated community and the atmosphere for 2 years by using static chambers.Important Findings We found that the seasonal changes in CO_(2) fluxes were apparent and dependent on the biophysical environment.In the beginning of spring,low gross primary productivity(GPP)in lightly flooded zones(LFZ)resulted in a positive net ecosystem exchange(NEE),indicating a net CO_(2) source.With the increase in temperature,more species and vegetation abundance appeared,and the increased GPP turned the LFZ from a net CO_(2) source into a sink.This transi-tion seemed predominantly controlled by the physiological growth of vegetation.The mean NEEs,REs and the light-use efficiency(α)of the vegetation at HFZ and MFZ were significantly higher than those at LFZ and UFZ.Yet the coefficients of variation(CV)of NEE and RE at MFZ and HFZ were lower than those at LFZ and UFZ.Submergence promoted the emission and uptake of CO_(2) to the atmosphere.Elongated submergence reduced the number of spe-cies and lowered the spatial variability of the RZ,further lowering the variation of the CO_(2) exchange.
文摘Due to questions raised regarding authorship of the article entitled“Evolutionary thinking in restoration under global environmental changes”by Chuanhua Wang,Tianhua He and Fangqing Chen,published online:February 13,2013(http://jpe.oxfordjournals.org/content/early/2013/02/05/jpe.rtt005.full)in Journal of Plant Ecology(DOI:10.1093/jpe/rtt005),the editors have requested it be retracted from the journal.
