Anthropogenic disturbances are widespread in tropical forests and influence the species composition in the overstory.However,the impacts of historical disturbance on tropical forest overstory recovery are unclear due ...Anthropogenic disturbances are widespread in tropical forests and influence the species composition in the overstory.However,the impacts of historical disturbance on tropical forest overstory recovery are unclear due to a lack of disturbance data,and previous studies have focused on understory species.In this study,the purpose was to deter-mine the influence of historical disturbance on the diver-sity,composition and regeneration of overstory species in present forests.In the 20-ha Xishuangbanna tropical sea-sonal rainforest dynamics plot in southwestern China,the historical disturbance boundaries were delineated based on panchromatic photographs from 1965.Factors that drove species clustering in the overstory layer(DBH≥40 cm)were analyzed and the abundance,richness and composition of these species were compared among different tree groups based on multiple regression tree analysis.The coefficient of variation of the brightness value in historical panchro-matic photographs from 1965 was the primary driver of spe-cies clustering in the overstory layer.The abundance and richness of overstory species throughout the regeneration process were similar,but species composition was always different.Although the proportion of large-seeded and vigorous-sprouting species showed no significant differ-ence between disturbed and undisturbed forests in the tree-let layer(DBH<20 cm),the difference became significant when DBH increased.The findings highlight that historical disturbances have strong legacy effects on functional group composition in the overstory and the recovery of overstory species was multidimensional.Functional group composi-tion can better indicate the dynamics of overstory species replacement during secondary succession.展开更多
Aims The evolutionary history and functional traits of species can illumi-nate ecological processes supporting coexistence in diverse forest communities.However,little has been done in decoupling the rela-tive importa...Aims The evolutionary history and functional traits of species can illumi-nate ecological processes supporting coexistence in diverse forest communities.However,little has been done in decoupling the rela-tive importance of these mechanisms on the turnover of phylogenetic and functional characteristics across life stages and spatial scales.Therefore,this study aims to estimate the contribution of environment and dispersal on the turnover of phylogenetic and functional diversity across life stages and spatial scales,in order to build a coherent pic-ture of the processes responsible for species coexistence.Methods We conducted the study in Xishuangbanna Forest Dynamics Plot in Yunnan Province,southwest China.We used four different spatial point process models to estimate the relative importance of disper-sal limitation and environmental filtering.The functional traits and phylogenetic relationships of all individual trees were incorporated in the analyses to generate measures of dissimilarity in terms of pair-wise and nearest-neighbor phylogenetic and functional characteris-tics across life stages and spatial scales.Important Findings We found non-random patterns of phylogenetic and functional turnover across life stages and spatial scales.Environmental filtering structured pairwise phylogenetic and functional beta diversity across spatial scales,while dispersal limitation alone,and in combination with environment filtering,shaped nearest neighbor phylogenetic and functional beta diversity.The relative importance of dispersal limitation and environmental filtering appeared to change with life stage but not with spatial scale.Our findings suggest that phylogenetic and functional beta diversity help to reveal the ecological processes responsible for evolu-tionary and functional assembly and highlight the importance of using a range of different metrics to gain full insights into these processes.展开更多
Terrestrial species are predicted to migrate northward under global warming conditions,yet little is known about the direction and magnitude of change in microbial distribution patterns.In this continental-scale study...Terrestrial species are predicted to migrate northward under global warming conditions,yet little is known about the direction and magnitude of change in microbial distribution patterns.In this continental-scale study with more than 1600 forest soil samples,we verify the existence of core microbiota and lump them into a manageable number of eco-clusters based on microbial habitat preferences.By projecting the abundance differences of eco-clusters between future and current climatic conditions,we observed the potential warming-driven migration of the core microbiota under warming,partially verified by a field warming experiment at Southwest China.Specifically,the species that favor low p H are potentially expanding and moving northward to medium-latitudes(25°–45°N),potentially implying that warm temperate forest would be under threat of soil acidification with warming.The eco-cluster of high-p H with high-annual mean temperature(AMT)experienced significant abundance increases at middle-(35°–45°N)to high-latitudes(>45°N),especially under Representative Concentration Pathway(RCP)8.5,likely resulting in northward expansion.Furthermore,the eco-cluster that favors low-soil organic carbon(SOC)was projected to increase under warming scenarios at low-latitudes(<25°N),potentially an indicator of SOC storage accumulation in warmer areas.Meanwhile,at high-latitudes(>45°N)the changes in relative abundance of this eco-cluster is inversely related with the temperature variation trends,suggesting microbes-mediated soil organic carbon changes are more responsive to temperature variation in colder areas.These results have vital implications for the migration direction of microbial communities and its potential ecological consequences in future warming scenarios.展开更多
Biochar can enhance crop production and sequester carbon,but there have been few studies with tree crops.Rubber plantations cover more than 8 million hectares in Southeast Asia,so we assessed the feasibility of biocha...Biochar can enhance crop production and sequester carbon,but there have been few studies with tree crops.Rubber plantations cover more than 8 million hectares in Southeast Asia,so we assessed the feasibility of biochar application in these plantations with a pot trial.Rubber seedlings were planted in soil with four concentrations(0,1.25%,2.5% and 5%,w/w)of biochar combined with two concentrations of compound fertilizer(0 kg/ha and 300 kg/ha).Soil properties and seedling growth were measured,and a leaching experiment was conducted in the rainy season.Our results show that biochar increased pH,water content(27.4-65.1%),total carbon(25.4-53.6%),nitrate nitrogen,and available phosphorus in the soil,and decreased bulk density(3.2-23.9%).Biochar treatment reduced leaching of ammonium nitrogen and ortho-P.Biochar increased seedling nutrient uptake(C,N,P and K),with 2.5% and 5% biochar showing the largest effects,but seedling biomass was the highest with 1.25%,and declined in 2.5% and 5%.Our results suggest that biochar addition is an effective way to improve rubber plantation soils,sequester more carbon and decrease nutrient leaching,but the optimum application rate under field conditions needs further research.展开更多
基金supported by the Natural Science Foundation of Yunnan Province(Grant No:202301AT070356)the Open Fund of the Key Laboratory of Tropical Forest Ecology,Chinese Academy of Sciences,National Science Foundation of China(Grant No.32061123003)+1 种基金the Joint Fund of the National Natural Science Foundation of China-Yunnan Province(Grant No.U1902203)the Field Station Foundation of the Chinese Academy of Sciences.
文摘Anthropogenic disturbances are widespread in tropical forests and influence the species composition in the overstory.However,the impacts of historical disturbance on tropical forest overstory recovery are unclear due to a lack of disturbance data,and previous studies have focused on understory species.In this study,the purpose was to deter-mine the influence of historical disturbance on the diver-sity,composition and regeneration of overstory species in present forests.In the 20-ha Xishuangbanna tropical sea-sonal rainforest dynamics plot in southwestern China,the historical disturbance boundaries were delineated based on panchromatic photographs from 1965.Factors that drove species clustering in the overstory layer(DBH≥40 cm)were analyzed and the abundance,richness and composition of these species were compared among different tree groups based on multiple regression tree analysis.The coefficient of variation of the brightness value in historical panchro-matic photographs from 1965 was the primary driver of spe-cies clustering in the overstory layer.The abundance and richness of overstory species throughout the regeneration process were similar,but species composition was always different.Although the proportion of large-seeded and vigorous-sprouting species showed no significant differ-ence between disturbed and undisturbed forests in the tree-let layer(DBH<20 cm),the difference became significant when DBH increased.The findings highlight that historical disturbances have strong legacy effects on functional group composition in the overstory and the recovery of overstory species was multidimensional.Functional group composi-tion can better indicate the dynamics of overstory species replacement during secondary succession.
基金National Natural Science Foundation of China(31400362 and 31670442)the National Key Basic Research Program of China(2014CB954100)+1 种基金the West Light Foundation of the Chinese Academy of Sciences and the Chinese Academy of Sciences Youth Innovation Promotion Association(2016352)the Applied Fundamental Research Foundation of Yunnan Province(2014GA003).
文摘Aims The evolutionary history and functional traits of species can illumi-nate ecological processes supporting coexistence in diverse forest communities.However,little has been done in decoupling the rela-tive importance of these mechanisms on the turnover of phylogenetic and functional characteristics across life stages and spatial scales.Therefore,this study aims to estimate the contribution of environment and dispersal on the turnover of phylogenetic and functional diversity across life stages and spatial scales,in order to build a coherent pic-ture of the processes responsible for species coexistence.Methods We conducted the study in Xishuangbanna Forest Dynamics Plot in Yunnan Province,southwest China.We used four different spatial point process models to estimate the relative importance of disper-sal limitation and environmental filtering.The functional traits and phylogenetic relationships of all individual trees were incorporated in the analyses to generate measures of dissimilarity in terms of pair-wise and nearest-neighbor phylogenetic and functional characteris-tics across life stages and spatial scales.Important Findings We found non-random patterns of phylogenetic and functional turnover across life stages and spatial scales.Environmental filtering structured pairwise phylogenetic and functional beta diversity across spatial scales,while dispersal limitation alone,and in combination with environment filtering,shaped nearest neighbor phylogenetic and functional beta diversity.The relative importance of dispersal limitation and environmental filtering appeared to change with life stage but not with spatial scale.Our findings suggest that phylogenetic and functional beta diversity help to reveal the ecological processes responsible for evolu-tionary and functional assembly and highlight the importance of using a range of different metrics to gain full insights into these processes.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB15010300)the National Science Foundation of China(U1602234,41807316,41471218,41501282,and 31870467)+1 种基金the CAS 135 project(2017XTBG-F01)the National Key Research and Development Program(2016YFC0500702)。
文摘Terrestrial species are predicted to migrate northward under global warming conditions,yet little is known about the direction and magnitude of change in microbial distribution patterns.In this continental-scale study with more than 1600 forest soil samples,we verify the existence of core microbiota and lump them into a manageable number of eco-clusters based on microbial habitat preferences.By projecting the abundance differences of eco-clusters between future and current climatic conditions,we observed the potential warming-driven migration of the core microbiota under warming,partially verified by a field warming experiment at Southwest China.Specifically,the species that favor low p H are potentially expanding and moving northward to medium-latitudes(25°–45°N),potentially implying that warm temperate forest would be under threat of soil acidification with warming.The eco-cluster of high-p H with high-annual mean temperature(AMT)experienced significant abundance increases at middle-(35°–45°N)to high-latitudes(>45°N),especially under Representative Concentration Pathway(RCP)8.5,likely resulting in northward expansion.Furthermore,the eco-cluster that favors low-soil organic carbon(SOC)was projected to increase under warming scenarios at low-latitudes(<25°N),potentially an indicator of SOC storage accumulation in warmer areas.Meanwhile,at high-latitudes(>45°N)the changes in relative abundance of this eco-cluster is inversely related with the temperature variation trends,suggesting microbes-mediated soil organic carbon changes are more responsive to temperature variation in colder areas.These results have vital implications for the migration direction of microbial communities and its potential ecological consequences in future warming scenarios.
基金This research was supported by the"Strategic Priority Research Program"of the Chinese Academy of Sciences(XDA05070304)the CAS 135 Program(XTBG-T03),Key program of NSF(31290221)the Science and Technology Service Network Initiative of Chinese Academy of Sciences(No.KFJ-EW-STS-084).
文摘Biochar can enhance crop production and sequester carbon,but there have been few studies with tree crops.Rubber plantations cover more than 8 million hectares in Southeast Asia,so we assessed the feasibility of biochar application in these plantations with a pot trial.Rubber seedlings were planted in soil with four concentrations(0,1.25%,2.5% and 5%,w/w)of biochar combined with two concentrations of compound fertilizer(0 kg/ha and 300 kg/ha).Soil properties and seedling growth were measured,and a leaching experiment was conducted in the rainy season.Our results show that biochar increased pH,water content(27.4-65.1%),total carbon(25.4-53.6%),nitrate nitrogen,and available phosphorus in the soil,and decreased bulk density(3.2-23.9%).Biochar treatment reduced leaching of ammonium nitrogen and ortho-P.Biochar increased seedling nutrient uptake(C,N,P and K),with 2.5% and 5% biochar showing the largest effects,but seedling biomass was the highest with 1.25%,and declined in 2.5% and 5%.Our results suggest that biochar addition is an effective way to improve rubber plantation soils,sequester more carbon and decrease nutrient leaching,but the optimum application rate under field conditions needs further research.
