The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better unde...The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better understand characteristics of soil CO2 flux （FCO2） in subtropical forests, soil FCO2 rates were quantified in five adjacent forest types （camphor tree forest, Masson pine forest, mixed camphor tree and Masson pine forest, Chinese sweet gum forest, and slash pine forest） at the Tianjiling National Park in Changsha, Hunan Province, in subtropical China, from January to December 2010. The influences of soil temperature （Tsoil）, volumetric soil water content （0soiI）, soil pH, soil organic carbon （SOC） and soil C/nitrogen （N） ratio on soil FCO2 rates were also investigated. The annual mean soil FCO2 rate varied with the forest types. The soil FCO2 rate was the highest in the camphor tree forest （3.53 ± 0.51 μmol m-2 s-I）, followed by, in order, the mixed, Masson pine, Chinese sweet gum, and slash pine forests （1.53 ± 0.25 μmol m-2 sl）. Soil FCO2 rates from the five forest types followed a similar seasonal pattern with the maximum values occurring in summer （July and August） and the minimum values during winter （December and January）. Soil FCO2 rates were correlated to Tsoil and 0soil, but the relationships were only significant for Tsoil. No correlations were found between soil FCO2 rates and other selected soil properties, such as soil pH, SOC, and C/N ratio, in the examined forest types. Our results indicated that soil FCO2 rates were much higher in the evergreen broadleaved forest than coniferous forest under the same microclimatic environment in the study region.展开更多
Aims Climate warming raises the probability of range expansions of warm-adapted temperate species into areas currently dominated by cold-adapted boreal species.Warming-induced plant range expansions could partly depen...Aims Climate warming raises the probability of range expansions of warm-adapted temperate species into areas currently dominated by cold-adapted boreal species.Warming-induced plant range expansions could partly depend on how warming modifies relationships with soil biota that promote plant growth,such as by mineralizing nutri-ents.Here,we grew two pairs of congeneric herbaceous plants spe-cies together in soil with a 5-year warming history(ambient,+1.7℃,+3.4℃)and related their performances to plant-beneficial soil biota.Methods Each plant pair belonged to either the mid-latitude temperate climate or the higher latitude southern boreal climate.Warmed soils were extracted from a chamberless heating experiment at two field sites in the temperate-boreal ecotone of North America.To isolate poten-tial effects of different soil warming histories,air temperature for the greenhouse experiment was identical across soils.We hypothesized that soil with a 5-year warming history in the field would enhance the performance of temperate plant species more than boreal plant species and expected improved plant performances to have positive associations with plant growth-promoting soil biota(microbial-feeding nematodes and arbuscular mycorrhizal fungi).Important Findings Our main hypothesis was partly confirmed as only one temperate spe-cies performed better in soil with warming history than in soil with his-tory of ambient temperature.Further,this effect was restricted to the site with higher soil water content in the growing season of the sampling year(prior to soil collection).One of the boreal species performed con-sistently worse in previously warmed soil,whereas the other species showed neutral responses to soil warming history.We found a positive correlation between the density of microbial-feeding nematodes and the performance of one of the temperate species in previously wetter soils,but this correlation was negative at the site with previously drier soil.We found no significant correlations between the performance of the other temperate species as well as the two boreal species and any of the studied soil biota.Our results indicate that soil warming can modify the relation between certain plant species and microbial-feeding nematodes in given soil edaphic conditions,which might be important for plant performance in the temperate-boreal ecotone.展开更多
基金Supported by the National Forestry Public Welfare Research Program of China(Nos.201104005 and 200804030)the Program for New Century Excellent Talents in University of Ministry of Education of China(No.NCET-10-0151)+1 种基金the 100 Talents Program of Hunan Province,China(No.2011516)Central South University of Forestry and Technology,China(No.0842)
文摘The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better understand characteristics of soil CO2 flux （FCO2） in subtropical forests, soil FCO2 rates were quantified in five adjacent forest types （camphor tree forest, Masson pine forest, mixed camphor tree and Masson pine forest, Chinese sweet gum forest, and slash pine forest） at the Tianjiling National Park in Changsha, Hunan Province, in subtropical China, from January to December 2010. The influences of soil temperature （Tsoil）, volumetric soil water content （0soiI）, soil pH, soil organic carbon （SOC） and soil C/nitrogen （N） ratio on soil FCO2 rates were also investigated. The annual mean soil FCO2 rate varied with the forest types. The soil FCO2 rate was the highest in the camphor tree forest （3.53 ± 0.51 μmol m-2 s-I）, followed by, in order, the mixed, Masson pine, Chinese sweet gum, and slash pine forests （1.53 ± 0.25 μmol m-2 sl）. Soil FCO2 rates from the five forest types followed a similar seasonal pattern with the maximum values occurring in summer （July and August） and the minimum values during winter （December and January）. Soil FCO2 rates were correlated to Tsoil and 0soil, but the relationships were only significant for Tsoil. No correlations were found between soil FCO2 rates and other selected soil properties, such as soil pH, SOC, and C/N ratio, in the examined forest types. Our results indicated that soil FCO2 rates were much higher in the evergreen broadleaved forest than coniferous forest under the same microclimatic environment in the study region.
基金German Research Foundation(DFG)in the frame of the Emmy Noether research group(Ei 862/2)German Centre for Integrative Biodiversity Research(iDiv)Halle-Jena-Leipzig,funded by the German Research Foundation(FZT 118)+1 种基金the US Department of Energy(DE-FG02-07ER64456)the College of Food,Agricultural and Natural Resource Sciences(CFANS)at the University of Minnesota.
文摘Aims Climate warming raises the probability of range expansions of warm-adapted temperate species into areas currently dominated by cold-adapted boreal species.Warming-induced plant range expansions could partly depend on how warming modifies relationships with soil biota that promote plant growth,such as by mineralizing nutri-ents.Here,we grew two pairs of congeneric herbaceous plants spe-cies together in soil with a 5-year warming history(ambient,+1.7℃,+3.4℃)and related their performances to plant-beneficial soil biota.Methods Each plant pair belonged to either the mid-latitude temperate climate or the higher latitude southern boreal climate.Warmed soils were extracted from a chamberless heating experiment at two field sites in the temperate-boreal ecotone of North America.To isolate poten-tial effects of different soil warming histories,air temperature for the greenhouse experiment was identical across soils.We hypothesized that soil with a 5-year warming history in the field would enhance the performance of temperate plant species more than boreal plant species and expected improved plant performances to have positive associations with plant growth-promoting soil biota(microbial-feeding nematodes and arbuscular mycorrhizal fungi).Important Findings Our main hypothesis was partly confirmed as only one temperate spe-cies performed better in soil with warming history than in soil with his-tory of ambient temperature.Further,this effect was restricted to the site with higher soil water content in the growing season of the sampling year(prior to soil collection).One of the boreal species performed con-sistently worse in previously warmed soil,whereas the other species showed neutral responses to soil warming history.We found a positive correlation between the density of microbial-feeding nematodes and the performance of one of the temperate species in previously wetter soils,but this correlation was negative at the site with previously drier soil.We found no significant correlations between the performance of the other temperate species as well as the two boreal species and any of the studied soil biota.Our results indicate that soil warming can modify the relation between certain plant species and microbial-feeding nematodes in given soil edaphic conditions,which might be important for plant performance in the temperate-boreal ecotone.
