A study was conducted to test the correlation between biomass and elevation and the differences in concentration and storks of nutrients among five vegetation types （Felsenmeer alpine tundra vegetation-FA, Lithic alp...A study was conducted to test the correlation between biomass and elevation and the differences in concentration and storks of nutrients among five vegetation types （Felsenmeer alpine tundra vegetation-FA, Lithic alpine tundra vegetation-LA, Typical alpine tundra vegetation-TA, Meadow alpine tundra vegetation-MA, and Swamp alpine tundra vegetation-SA） on alpine tundra of Changbai Mountains, Jilin Province, China in growing seasons of 2003, 2004 and 2005. The biomass of 43 mono-species and soil nutrients in alpine tundra ecosystem were also investigated. Dominant species from Ericaceae （such as Rhododendron chrysanthum and Vaccinium jliginosum var. alpinum） were taken to analyze organ biomass distribution. Result showed that the biomass and elevation had a significant correlation （Biomass-237.3 in（Elevation） ＋494.36; R^2=0.8092; P〈0.05）. No significant differences were found in phosphorus and sulphur concentrations of roots, stems and leaves among the five vegetation types. There were significant differences in nitrogen and phosphorus stocks of roots, stems and leaves and in sulphur stock of stems and leaves among TA, MA, and SA vegetation types （p〈0.05）. The nutrient stock of five vegetations was averagely 72.46 kg.hm^-2, of which N, P, S were 48.55, 10.33 and 13.61 kg·hm^-2, respectively. Soil N and S concentrations in meadow alpine tundra soil type was significantly higher than those in other four soil types （Cold desert alpine tundra soil, Lithic alpine tundra soil, Peat alpine tundra soil, and Gray alpine tundra soil）. Phosphorous concentration in SA type was higher （p〈0.05） than in other types. Soil nutrient stock （0-20cm） was averagely 39.59 t.hm^-2, of which N, P, S were 23.74, 5.86, 9.99 t·hm^-2, respectively.展开更多
In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different...In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different depths were significantly (p<0.05) higher in Meadow alpine tundra vegetation than that in other vegetation types; the soil C (including inorganic carbon) concentrations at layer below 10 cm are significantly (p<0.05) higher than at layer of 1020 cm among the different vegetation types; the spatial distribution of soil N concentration at top surface of 0-10 cm depth was similar to that at 1020 cm; the soil P concentrations at different depths were significantly (p<0.05) lower at Lithic alpine tundra vegetation than that at other vegetation types; soil K concentration was significantly (p<0.05) higher in Felsenmeer alpine tundra vegetation and Lithic alpine tundra vegetation than that in Typical alpine tundra, Meadow alpine tundra, and Swamp alpine tundra vegetations.. However, the soil K had not significant change at different soil depths of each vegetation type. Soil S concentration was dramatically higher in Meadow alpine tundra vegetation than that in other vegetation types. For each vegetation type, the ratios of C: N, C: P, C: K and C: S generally decreased with soil depth. The ratio of C: N was significantly higher at 010 cm than that at 1020 cm for all vegetation types except at the top layer of the Swamp alpine tundra vegetation. Our study showed that soil C and nutrients storage were significantly spatial heterogeneity.展开更多
Soil moisture is an important resource for plant growth on the arid and semi-arid Loess Plateau of China where the‘‘Grain for Green’’project was launched in 1999,but there has been no systematic evaluation of soil...Soil moisture is an important resource for plant growth on the arid and semi-arid Loess Plateau of China where the‘‘Grain for Green’’project was launched in 1999,but there has been no systematic evaluation of soil moisture from the effects of ecological restoration at a regional scale.We systematically assessed 63 published studies during 2000-2015,including 2050 observations at 68 sites on the Loess Plateau with the aim of determining soil moisture changes and the factors influencing those changes.We found that,after land use conversion,soil moisture decreased by 17%in the upper 100 cm soil layer and that tree plantations and shrub lands appeared to cause soil moisture depletion which became increasingly serious with soil depth.The decrease of soil moisture was significantly influenced by the planting species in all restoration types(tree plantations,shrub lands,and grasslands).We also found that tree plantations and grasslands converted from farmlands consumed more soil moisture than from wasteland(including bare land,abandoned land and wild grasslands).Artificial restoration led to significant soil moisture reduction,but natural restoration had little effect on soil moisture.Therefore,natural restoration should be an alternative restoration practice on the Loess Plateau.These results will provide helpful information for artificial afforestation and planning ecological restoration campaigns for policy makers on water-limited regions.展开更多
The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic ca...The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic carbon(SOC)after reforestation.In this study,150 reforested plots were sampled across six provinces and one municipality in the Yangtze River Basin(YRB)during 2017 and 2018 to estimate carbon storage in biomass and soil.The results illustrate that site-averaged SOC was greater than site-averaged biomass carbon.There was more carbon sequestered in the biomass than in the soil.Biomass carbon accumulated rapidly in the initial 20 years after planting.In contrast,SOC sequestration increased rapidly after 20 years.In addition,evergreen species had higher carbon density in both biomass and soil than deciduous species and economic species(fruit trees).Carbon sequestration in evergreen and deciduous species is greater than in economic species.Our findings provide new evidence on the divergent responses of biomass and soil to carbon sequestration after reforestation with respect to stand ages and vegetation types.This study provides relevant information for ecosystem management as well as for carbon sequestration and global climate change policies.展开更多
Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cy...Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cycles, each natural forst landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape variability.Methods: The study encompassed a forested area of 175 000 km2 divided into 14 landscapes. Using a framework that integrates fire cycles, age structure and forest dynamics, we characterized the forest composition and age structures that resulted from three historical fire cycles(110,140, and 180 years) representative of the boreal forest of eastern Canada. The modeled natural landscapes were compared with present-day landscapes in regard to the proportion of old-growth forests(landscape level) and the proportion of late-successional forest stands(landscape level and potential vegetation type).Results: Four landscapes(39%) remain within their natural range of variability. In contrast, nine landscapes(54%)show a large gap between natural and present-day landscapes. These nine are located in the southern portion of the study area, and are mainly associated with Abies-Betula vegetation where human activities have contributed to a strong increase in the proportion of Populus tremuloides stands(early-successional stages) and a decrease of oldgrowth forest stands(more than 100 years old). A single landscape(7%), substantially changed from its potential natural state, is a candidate for adaptive-based management.Conclusion: Comparison of corresponding natural(reference conditions) and present-day landscapes showed that ten landscapes reflecting an important shift in forest composition and age structure could be considered beyond the range of their natural variability. The description of a landscape's natural variability at the scale of several millennia can be considered a moving benchmark that can be re-evaluated in the context of climate change.Focusing on regional landscape characteristics and long-term natural variability of vegetation and forest age structure represents a step forward in methodology for defining reference conditions and following shifts in landscape over time.展开更多
基金This research was supported by National Natural Science Foundation of China (No: 40473054)Agricultural Technological Production Translation of Science and Technology of Ministry (No:05EFN216600446).
文摘A study was conducted to test the correlation between biomass and elevation and the differences in concentration and storks of nutrients among five vegetation types （Felsenmeer alpine tundra vegetation-FA, Lithic alpine tundra vegetation-LA, Typical alpine tundra vegetation-TA, Meadow alpine tundra vegetation-MA, and Swamp alpine tundra vegetation-SA） on alpine tundra of Changbai Mountains, Jilin Province, China in growing seasons of 2003, 2004 and 2005. The biomass of 43 mono-species and soil nutrients in alpine tundra ecosystem were also investigated. Dominant species from Ericaceae （such as Rhododendron chrysanthum and Vaccinium jliginosum var. alpinum） were taken to analyze organ biomass distribution. Result showed that the biomass and elevation had a significant correlation （Biomass-237.3 in（Elevation） ＋494.36; R^2=0.8092; P〈0.05）. No significant differences were found in phosphorus and sulphur concentrations of roots, stems and leaves among the five vegetation types. There were significant differences in nitrogen and phosphorus stocks of roots, stems and leaves and in sulphur stock of stems and leaves among TA, MA, and SA vegetation types （p〈0.05）. The nutrient stock of five vegetations was averagely 72.46 kg.hm^-2, of which N, P, S were 48.55, 10.33 and 13.61 kg·hm^-2, respectively. Soil N and S concentrations in meadow alpine tundra soil type was significantly higher than those in other four soil types （Cold desert alpine tundra soil, Lithic alpine tundra soil, Peat alpine tundra soil, and Gray alpine tundra soil）. Phosphorous concentration in SA type was higher （p〈0.05） than in other types. Soil nutrient stock （0-20cm） was averagely 39.59 t.hm^-2, of which N, P, S were 23.74, 5.86, 9.99 t·hm^-2, respectively.
基金This research was supported by National Natural Science Foundation of China (40173033) and Important Direction Project of Knowl-edge Innovation of Chinese Academy of Sciences (KZCX3-SW-423).
文摘In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different depths were significantly (p<0.05) higher in Meadow alpine tundra vegetation than that in other vegetation types; the soil C (including inorganic carbon) concentrations at layer below 10 cm are significantly (p<0.05) higher than at layer of 1020 cm among the different vegetation types; the spatial distribution of soil N concentration at top surface of 0-10 cm depth was similar to that at 1020 cm; the soil P concentrations at different depths were significantly (p<0.05) lower at Lithic alpine tundra vegetation than that at other vegetation types; soil K concentration was significantly (p<0.05) higher in Felsenmeer alpine tundra vegetation and Lithic alpine tundra vegetation than that in Typical alpine tundra, Meadow alpine tundra, and Swamp alpine tundra vegetations.. However, the soil K had not significant change at different soil depths of each vegetation type. Soil S concentration was dramatically higher in Meadow alpine tundra vegetation than that in other vegetation types. For each vegetation type, the ratios of C: N, C: P, C: K and C: S generally decreased with soil depth. The ratio of C: N was significantly higher at 010 cm than that at 1020 cm for all vegetation types except at the top layer of the Swamp alpine tundra vegetation. Our study showed that soil C and nutrients storage were significantly spatial heterogeneity.
文摘Soil moisture is an important resource for plant growth on the arid and semi-arid Loess Plateau of China where the‘‘Grain for Green’’project was launched in 1999,but there has been no systematic evaluation of soil moisture from the effects of ecological restoration at a regional scale.We systematically assessed 63 published studies during 2000-2015,including 2050 observations at 68 sites on the Loess Plateau with the aim of determining soil moisture changes and the factors influencing those changes.We found that,after land use conversion,soil moisture decreased by 17%in the upper 100 cm soil layer and that tree plantations and shrub lands appeared to cause soil moisture depletion which became increasingly serious with soil depth.The decrease of soil moisture was significantly influenced by the planting species in all restoration types(tree plantations,shrub lands,and grasslands).We also found that tree plantations and grasslands converted from farmlands consumed more soil moisture than from wasteland(including bare land,abandoned land and wild grasslands).Artificial restoration led to significant soil moisture reduction,but natural restoration had little effect on soil moisture.Therefore,natural restoration should be an alternative restoration practice on the Loess Plateau.These results will provide helpful information for artificial afforestation and planning ecological restoration campaigns for policy makers on water-limited regions.
基金The work was supported by the Research Grants Council of the Hong Kong Special Administrative Region,China[grant number 12305116].
文摘The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic carbon(SOC)after reforestation.In this study,150 reforested plots were sampled across six provinces and one municipality in the Yangtze River Basin(YRB)during 2017 and 2018 to estimate carbon storage in biomass and soil.The results illustrate that site-averaged SOC was greater than site-averaged biomass carbon.There was more carbon sequestered in the biomass than in the soil.Biomass carbon accumulated rapidly in the initial 20 years after planting.In contrast,SOC sequestration increased rapidly after 20 years.In addition,evergreen species had higher carbon density in both biomass and soil than deciduous species and economic species(fruit trees).Carbon sequestration in evergreen and deciduous species is greater than in economic species.Our findings provide new evidence on the divergent responses of biomass and soil to carbon sequestration after reforestation with respect to stand ages and vegetation types.This study provides relevant information for ecosystem management as well as for carbon sequestration and global climate change policies.
基金funded by the Ministère des Forêts,de la Faune et des Parcs du Québec(MFFP).The funds were used mainly for the salary of the authors working for the MFFP
文摘Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cycles, each natural forst landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape variability.Methods: The study encompassed a forested area of 175 000 km2 divided into 14 landscapes. Using a framework that integrates fire cycles, age structure and forest dynamics, we characterized the forest composition and age structures that resulted from three historical fire cycles(110,140, and 180 years) representative of the boreal forest of eastern Canada. The modeled natural landscapes were compared with present-day landscapes in regard to the proportion of old-growth forests(landscape level) and the proportion of late-successional forest stands(landscape level and potential vegetation type).Results: Four landscapes(39%) remain within their natural range of variability. In contrast, nine landscapes(54%)show a large gap between natural and present-day landscapes. These nine are located in the southern portion of the study area, and are mainly associated with Abies-Betula vegetation where human activities have contributed to a strong increase in the proportion of Populus tremuloides stands(early-successional stages) and a decrease of oldgrowth forest stands(more than 100 years old). A single landscape(7%), substantially changed from its potential natural state, is a candidate for adaptive-based management.Conclusion: Comparison of corresponding natural(reference conditions) and present-day landscapes showed that ten landscapes reflecting an important shift in forest composition and age structure could be considered beyond the range of their natural variability. The description of a landscape's natural variability at the scale of several millennia can be considered a moving benchmark that can be re-evaluated in the context of climate change.Focusing on regional landscape characteristics and long-term natural variability of vegetation and forest age structure represents a step forward in methodology for defining reference conditions and following shifts in landscape over time.
