Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geom...Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geomorphometric terrain analyses were carried out at a spatial resolution of 5×5 m.Soil samples of different depth increments and data on tree height were collected from a total of 566 plots(667 m2 each).The soils were analyzed for carbon(soil organic carbon[SOC]),nitrogen,acidity,cation exchange capacity(CEC),exchangeable cations and base saturation as soil fertility attributes.All plots were classified into geomorphological units.Analyses of variance and linear regressions were applied to all terrain,soil fertility and tree growth attributes.Important Findings In general,young and shallow soils and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment.This explains the concurrently increasing CEC and SOC stocks downslope,in hollows and in valleys.However,colluvial,carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways.The results showed that soil fertility is mainly influenced by topography.Monte-Carlo flow accumulation(MCCA),curvature,slope and aspect significantly affected soil fertility.Furthermore,soil fertility was affected by the different geomorphological positions on the experimental sites with ridge and spur positions showing lower exchangeable base cation contents,especially potassium(K),due to leaching.This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth.Few soil fertility attributes affect tree height after 1-2 years of growth,among which C stocks proved to be most important while pH_(KCl)and CEC only played minor roles.Nevertheless,soil acidity and a high proportion of Al on the exchange complex affected tree height even after only 1-2 years growth.Hence,our study showed that forest nutrition is coupled to a recycling of litter nutrients,and does not only depend on subsequent supply of nutrients from the mineral soil.Besides soil fertility,topography affected tree height.We found that especially MCCA as indicator of water availability affected tree growth at small-scale,as well as aspect.Overall,our synthesis on the interrelation between fertility,topography and tree growth in a subtropical forest ecosystem in SE China showed that topographic heterogeneity lead to ecological gradients across geomorphological positions.In this respect,small-scale soil-plant interactions in a young forest can serve as a driver for the future development of vegetation and biodiversity control on soil fertility.In addition,it shows that terrain attributes should be accounted for in ecological research.展开更多
Labile organic carbon(LOC) is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the sou...Labile organic carbon(LOC) is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the sources and causes of LOC contamination are. In this study, soil organic carbon(SOC), total nitrogen(TN), microbial biomass carbon(MBC), microbial biomass nitrogen(MBN) and LOC were analyzed based on different soil horizons and elevations using turnover time in an experimental site(3700 m to 4300 m area) in Sygera. SOC and LOC in higher-elevation vegetation types were higher than that of in lower-elevation vegetation types. Our results presented that the soil microbial biomass carbon(SMBC) and soil microbial biomass nitrogen(SMBN)were positively correlated with SOC. The content of easily oxidized carbon(EOC), particulate organic carbon(POC) and light fraction organic carbon(LFOC) decreased with depth increasing and the content were the lowest in the 60 cm to 100 cm depth.The total SOC, ROC and POC contents decreased with increasing soil horizons. The SOC, TN, MBC and MBN contents increased with increasing altitude in the Sygera Mountains. The MBC and MBN contents weredifferent with the changes of SOC(p<0.05),meanwhile, both LFOC and POC were related to total SOC(p<0.05). The physical and chemical properties of soil, including temperature, humidity, and altitude,were involved in the regulation of SOC, TN, MBC,MBN and LFOC contents in the Sygera Mountains,Tibetan Plateau.展开更多
Invasive plant species and climate change are among the biggest threats to the ecological integrity of many ecosystems,including those of protected areas.Effective management of invasive plants requires information re...Invasive plant species and climate change are among the biggest threats to the ecological integrity of many ecosystems,including those of protected areas.Effective management of invasive plants requires information regarding their spatialdistributions Using maximum entropy,wemodeled habitat suitability for an invasive plant species Chromolaena odorata under current and future climatic conditions(HadGEM2-ESand MIROC5)in protected areas of four West African countries(Benin,Cote d'voire,Ghana,and Togo).Under current climatic conditions,approximately 73%of total land area within the protected areas was suitable for colonization by C.odorata.Under future climate projections,the total area of suitable habitats for this invasive plant was projected to decrease by 7-9%(HadGEM2-ES)and 12-14%(MIROC5).Country-specific patterns suggest that major protected areas in Cote d'Ivoire and Ghana will be more vulnerable to invasion by C.odorata than those in Benin and Togo under both current and future dimatic scenarios.To maintain normal ecosystem functioning and provisioning of ecosystem services within the protected areas studied here,locations that have been identified as most vulnerable to invasion by C.odorata should be accorded proportionately higher priority when formulating appropriate management strategies.展开更多
基金funded by the German Research Foundation(DFG FOR 891/1,2 and 3)funds from the National Natural Science Foundation of China(NSFC 30710103907,30930005,31170457 and 31210103910)+2 种基金the Swiss National Science Foundation(SNSF)financed by the Sino-German Centre for Research Promotion in Beijing(GZ 524,592,698,699 and 785)the University of Tübingen,Germany(PROMOS).
文摘Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geomorphometric terrain analyses were carried out at a spatial resolution of 5×5 m.Soil samples of different depth increments and data on tree height were collected from a total of 566 plots(667 m2 each).The soils were analyzed for carbon(soil organic carbon[SOC]),nitrogen,acidity,cation exchange capacity(CEC),exchangeable cations and base saturation as soil fertility attributes.All plots were classified into geomorphological units.Analyses of variance and linear regressions were applied to all terrain,soil fertility and tree growth attributes.Important Findings In general,young and shallow soils and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment.This explains the concurrently increasing CEC and SOC stocks downslope,in hollows and in valleys.However,colluvial,carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways.The results showed that soil fertility is mainly influenced by topography.Monte-Carlo flow accumulation(MCCA),curvature,slope and aspect significantly affected soil fertility.Furthermore,soil fertility was affected by the different geomorphological positions on the experimental sites with ridge and spur positions showing lower exchangeable base cation contents,especially potassium(K),due to leaching.This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth.Few soil fertility attributes affect tree height after 1-2 years of growth,among which C stocks proved to be most important while pH_(KCl)and CEC only played minor roles.Nevertheless,soil acidity and a high proportion of Al on the exchange complex affected tree height even after only 1-2 years growth.Hence,our study showed that forest nutrition is coupled to a recycling of litter nutrients,and does not only depend on subsequent supply of nutrients from the mineral soil.Besides soil fertility,topography affected tree height.We found that especially MCCA as indicator of water availability affected tree growth at small-scale,as well as aspect.Overall,our synthesis on the interrelation between fertility,topography and tree growth in a subtropical forest ecosystem in SE China showed that topographic heterogeneity lead to ecological gradients across geomorphological positions.In this respect,small-scale soil-plant interactions in a young forest can serve as a driver for the future development of vegetation and biodiversity control on soil fertility.In addition,it shows that terrain attributes should be accounted for in ecological research.
基金supported by CFERN & GENE Award Funds on Ecological Paper
文摘Labile organic carbon(LOC) is one of the most important indicators of soil organic matter quality and dynamics elevation and plays important function in the Tibetan Plateau climate. However, it is unknown what the sources and causes of LOC contamination are. In this study, soil organic carbon(SOC), total nitrogen(TN), microbial biomass carbon(MBC), microbial biomass nitrogen(MBN) and LOC were analyzed based on different soil horizons and elevations using turnover time in an experimental site(3700 m to 4300 m area) in Sygera. SOC and LOC in higher-elevation vegetation types were higher than that of in lower-elevation vegetation types. Our results presented that the soil microbial biomass carbon(SMBC) and soil microbial biomass nitrogen(SMBN)were positively correlated with SOC. The content of easily oxidized carbon(EOC), particulate organic carbon(POC) and light fraction organic carbon(LFOC) decreased with depth increasing and the content were the lowest in the 60 cm to 100 cm depth.The total SOC, ROC and POC contents decreased with increasing soil horizons. The SOC, TN, MBC and MBN contents increased with increasing altitude in the Sygera Mountains. The MBC and MBN contents weredifferent with the changes of SOC(p<0.05),meanwhile, both LFOC and POC were related to total SOC(p<0.05). The physical and chemical properties of soil, including temperature, humidity, and altitude,were involved in the regulation of SOC, TN, MBC,MBN and LFOC contents in the Sygera Mountains,Tibetan Plateau.
基金We acknowledge funding from International Young Scientist Fellowship of the Chinese Academy of Sciences(fellowship number 2012Y1ZA0009 for A.B.Fandohan and 2012Y1ZA0011 for A.M.O.Oduor)research grants from the National Natural Science Foundation of China(grant number 312111172 for A.B.Fandohan and 312111182 for A.M.O.Oduor).
文摘Invasive plant species and climate change are among the biggest threats to the ecological integrity of many ecosystems,including those of protected areas.Effective management of invasive plants requires information regarding their spatialdistributions Using maximum entropy,wemodeled habitat suitability for an invasive plant species Chromolaena odorata under current and future climatic conditions(HadGEM2-ESand MIROC5)in protected areas of four West African countries(Benin,Cote d'voire,Ghana,and Togo).Under current climatic conditions,approximately 73%of total land area within the protected areas was suitable for colonization by C.odorata.Under future climate projections,the total area of suitable habitats for this invasive plant was projected to decrease by 7-9%(HadGEM2-ES)and 12-14%(MIROC5).Country-specific patterns suggest that major protected areas in Cote d'Ivoire and Ghana will be more vulnerable to invasion by C.odorata than those in Benin and Togo under both current and future dimatic scenarios.To maintain normal ecosystem functioning and provisioning of ecosystem services within the protected areas studied here,locations that have been identified as most vulnerable to invasion by C.odorata should be accorded proportionately higher priority when formulating appropriate management strategies.