Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-1...Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-10 cm) from different subalpine forest types on east slope of Gongga Mountain in the upriver area of Yangtze River China in May 2002. The soil bulk density, porosity, stable infiltration rate, aggregate distribution and particle-size distribution were analyzed by the routine methods in room, and the features and effects on eco-environment of soil aggregation were studied. The results showed that the structure of soil under mixed mature forest is in the best condition and can clearly enhance the eco-environmental function of soil, and the soil structure under the clear-cutting forest is the worst, the others are ranked between them. The study results can offer a basic guidance for the eco-environmental construction in the upper reaches of Yangtze River.展开更多
There are abundant excellent tourism resources in Gongga mountainous areas (Mount Gongga, also known as Minya Konka, the highest mountain in Sichuan, China), yet the development thoughts and management modes in this r...There are abundant excellent tourism resources in Gongga mountainous areas (Mount Gongga, also known as Minya Konka, the highest mountain in Sichuan, China), yet the development thoughts and management modes in this region are far away from the advanced level in other mountainous areas in China or abroad due to the insufficient knowledge about ecotourism. Generally speaking, tourism development in Gongga mountainous areas are limited by various problems such as lack of overall development plan, system support, brand image, financial support and environmental protection consciousness. In view of the present situation of tourism development in this region, sustainable development measures are proposed on the basis of ecotourism and sustainable development theories, including making ecotourism development plan for Gongga mountainous areas, improving transportation conditions, tourism infrastructures and accommodation facilities, training service and management personnel with professional ecological knowledge; establishing ecotourism product system of Gongga mountainous areas; carrying out ecotourism management, innovating management system, setting up ecological monitoring system, implementing scientific functional division of tourism sites, constructing environment capacity control system and disasters management system of mountainous areas, improving medical and mountainous assistance system. Natural conditions and economic development of Gongga mountainous areas are similar to those in western China, it is expected to provide theoretical basis and practical experience for developing the vast mountainous areas in western China through studying the sustainable tourism development of Gongga mountainous areas.展开更多
Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water reg...Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water regime of soil and connected with the growth of plant, the study combined the moisture percentage of soil with PF to research in quantity the interrelation between the moisture percentage and PF in different succession phases of subalpine dark coniferous forest in Gongga Mountain. The results showed that: (1) In the same PF value, the moisture percentage in humus horizon increased gradually with the devel-opment of the succession of the dark coniferous forest; The moisture percentage of over-mature forest was the highest and>mature forest>half-mature forest>young growth forest; (2) With the increase of soil depth, the soil bulk density increased and the moisture percentage decreased, but the difference in the percentage of moisture was not notable in different succession phases. (3) In different succession series, the vegetation affected the soil water characteristics by increasing the soil organic matter, improving the soil construction, receding the soil bulk density and enhancing the soil porosity; (4) The humus horizon of the dark coniferous forest soil has the highest water holding capability in this region.展开更多
Gongga Mountain, locates on the eastern edge of Tibetan Plateau of China, is the highest mountain in China except summits in Tibet. Only limited meteorological data on Gongga Mountain have been published so far. Here ...Gongga Mountain, locates on the eastern edge of Tibetan Plateau of China, is the highest mountain in China except summits in Tibet. Only limited meteorological data on Gongga Mountain have been published so far. Here we present the meteorological records from two stations, Moxi Station (at 1,621.7 m above sea level (a.s.1.), 1992- 2010) and Hailuogou Station (at 2,947.8 m a.s.l., 1988-2010), on the eastern slope of Gongga Mountain. In the past two decades, the annual precipitation decreased while the annual mean temperature increased at Hailuogou Station. Both precipitation and temperature increased at Moxi Station. The precipitation variation on the eastern slope of Gongga Mountain is influenced by both East Asian Monsoon and Indian Monsoon, so that the precipitation concentrated between May and October. The temperature variation on the eastern slope of Gongga Mountain in the past two decades showed similar trends as that of the northern hemispheric and global. In the past two decades, the temperature increased o.35℃ and o.3℃/decade at Hailuogou Station and Moxi Station respectively, which was higher than the increase extents of northern hemispheric and global temperature. The most intense warming occurred at the first decade of 21St century. The winter temperature increased more at Hailuogou Station than at Moxi Station. A remarkable increase of temperature in March was observed with only a little precipitation at both high and low altitude stations.展开更多
The distribution of soil organic matter (SOM) and nitrogen on Gongga Mountain was studied in this paper. The results showed that the content of SOM and nitrogen (N) of A horizon had an ascending trend with the increas...The distribution of soil organic matter (SOM) and nitrogen on Gongga Mountain was studied in this paper. The results showed that the content of SOM and nitrogen (N) of A horizon had an ascending trend with the increase of the elevation. The vegetation types distributed higher than the mixed broad-leaved and coniferous forest have the irregular trends. In the transitional zone vegetation such as mixed trees and treeline, the content of SOM and N is higher than other vegetation types. The distribution of SOM and N of A horizon is dependent on the synthetic effect of climate and vegetation types. The vertical distribution of SOM and N in soil profiles has the similar trends for all kinds of vegetation types, i.e., the content of A horizon is higher than that of the B and C horizons, which is the same to the distribution of dead animal and plant in soil. The soil C:N is between 7 and 25, which is relatively low comparing to the appropriate C:N of 25-30. The ratio of soil carbon to nitrogen (C:N)increases with the increase of the elevation, but its vertical distribution in soil horizons varies with different vegetation types. The N exists in SOM mainly in the form of organic nitrogen, and the soil C:N correlates significantly with SOM.展开更多
Global climate change is having long-term impacts on the geographic distribution of forest species. However, the response of vertical belts of mountain forests to climate change is still little known. The vertical dis...Global climate change is having long-term impacts on the geographic distribution of forest species. However, the response of vertical belts of mountain forests to climate change is still little known. The vertical distribution of forest vegetation(vertical vegetation belt) on Gongga Mountain in Southwest China has been monitored for 30 years. The forest alternation of the vertical vegetation belt under different climate conditions was simulated by using a mathematical model GFSM(the Gongga Forest Succession Model). Three possible Intergovernmental Panel on Climate Change(IPCC) climate scenarios(increase of air temperature and precipitation by 1.8℃/5%, 2.8℃/10% and 3.4℃/15% for B_1, A_1B and A_2 scenarios, respectively) were chosen to reflect lower, medium and higher changes of global climate. The vertical belts of mountainous vegetation will shift upward by approximately 300 m, 500 m and 600 m in the B_1, A_1B and A_2 scenarios, respectively, according to the simulated results. Thus, the alpine tree-line will move to a higher altitude. The simulation also demonstrated that, in a changing climate, the shift in the vegetation community will be a slow and extended process characterized by two main phases. During the initial phase, trees of the forest community degrade or die, owing to an inability to adapt to a warmer climate. This results in modest environment for the introduction of opportunistic species, consequently, the vegetation with new dominant tree species becomes predominant in the space vacated by the dead trees at the expense of previously dominated original trees as the succession succeed and climate change advance. Hence, the global climate change would dramatically change forest communities and tree species in mountainous regions because that the new forest community can grow only through the death of the original tree. Results indicated that climate change will cause the change of distribution and composition of forest communities on Gongga Mountain, and this change may enhance as the intensity of climate change increases. As a result, the alternation of death and rebirth would finally result in intensive landscape changes, and may strongly affect the eco-environment of mountainous regions.展开更多
The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs (greenhouse gases) fluxes (CO2, NO and N2O) in forest ecosystems was applied to simulate carbon sequestration and GHGs e...The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs (greenhouse gases) fluxes (CO2, NO and N2O) in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga Mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production (GPP) of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production (NPP) was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production (NEP) was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively.展开更多
The Gongga Mountain of eastern Tibet Plateau is a representative of the alpine regions with high peaks and deep valleys. Climate change over the last thousand years has controlled the dynamics of glacier and debris fl...The Gongga Mountain of eastern Tibet Plateau is a representative of the alpine regions with high peaks and deep valleys. Climate change over the last thousand years has controlled the dynamics of glacier and debris flow occurrence, which resulted in substantial changes in the mountainous environment. The authors surveyed the community structure of primary forests in Gongga Mountain and forest succession processes in woodland plots. The changing features in the subalpine environment are discussed in this paper. Tree species and sizes between the glacier shrinking areas and debris flow fans in Hailuogou Valley are compared. The pioneer species that settle in debris flow fans and the glacier shrinking areas are Salix spp. and Populus purdomii. Abies fabri and Picea brachytyla are the climax tree species. The succession process of primary vegetation in Hailuogou (2700 ~ 3200 m) can be divided into four stages: Slash surface (20~ 200 yr) Salix-Populus seeding community (10 ~ 30 yr) Populus-Salix sapling community (30 ~ 100 yr) Populus-Abies mixed community (50 ~ 100 yr) Abies-Picea climax In a natural and undisturbed environment, trees compete for light, water and nutrients. Disaster disturbance in mountains is a very important driving factor for regeneration of woody plants. Repeated destruction of forests by glacier movement or debris flows generated additional forest gaps that allow young plants to grow. In this study the Gongga Forest Succession Model (GFSM) was developed for simulation of forest community succession processes on different scales in Gongga Mountain. A soil succession module was added to the GFSM model to simulate soil formation and chemical element change of woodland. In order to represent major features of forests in Southwestern China, many field works has been done to identify ecological parameters of various trees in the subalpine region. On the basis of simulation of tree life history, the GFSM combines forest succession with soil change in both material components and nutrition content. The Monte-Carlo method was applied to simulate random weather fluctuation and the uncertainty of tree death. These modeled processes agreed with the field investigation results in this region. The elevation distribution of different tree species was also simulated; and the results are consistent with field observations of ecological features of tree species. The modeling approach reflects well the succession dynamics of primary forests in Southwestern China. These results are very useful for improving the management policies and prediction technology for restoration and conservation of primary forests in Southwestern China.展开更多
Distribution characteristics of soil organic matter(SOM) and total nitrogen(TN) were studied in different plant communities of the Yajiageng vertical belt in Gongga Mountain around the Dadu River banks. The result...Distribution characteristics of soil organic matter(SOM) and total nitrogen(TN) were studied in different plant communities of the Yajiageng vertical belt in Gongga Mountain around the Dadu River banks. The results show: (1) the contents of SOM and TN of the plant communities gradually decreased with the following order: subalpine coniferous forest (3 027 m), subalpine meadow (3 873 m), coniferous broadleaved mixed forest(2 737 m), subalpine shrub(3 565 m) and treeline(3 564 m). (2) With soil profile depth increasing, the contents of SOM and TN gradually decreased. For different vegetation types, the contents of SOM and TN in sub-alpine coniferous forest were higher than that of other vegetational types. (3)The ratio of the content of carbon to the content of total nitrogen (Cc/CTN)WaS 13.5-27.6, which was relatively lower than the appropriate Cc/CTN of 25-30, and indicated that the soil in favor of the organic matter decomposed and nutrients released. Cc/CTN in the soil had no correlation with sea level altitude. However, its distribution in the soil x, aried with different vegetation types. (4) Nitrogen in SOM existed mainly in the form of organic nitrogen, and Cc/CTN in the soil was not obvious correlated with SOM and TN.展开更多
Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and th...Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury,their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However,only a few measurements of mercury,to our knowledge,have been done in ambient air over China. The highly-time resolved atmospheric mercury concen-trations have been measured at Moxi Base Station (102°72′E 29°92′N,1640 m asl) of the Gongga Alpine Ecosystem Observation and Experiment Station of Chinese Academy of Sciences (CAS) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A). Measurements were carried out with a time resolution of every 15 minutes. The overall average total gaseous mercury (TGM) covering the measurement periods was 4±1.38 ng·m-3 (N=57310),which is higher than the global background level of approximately 1.5~2.0 ng·m-3. The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally,it was found that the concentrations of TGM were highest in winter with 6.13 ± 1.78 ng·m-3 and lowest in summer with 3.17 ± 0.67 ng·m-3. There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters,such as temperature,saturated vapor pressure,precipitation,ultraviolet radiation (UV) and atmospheric pressure at the whole measurement stage,and the correlations varied seasonally. Our results suggest that the local or regional abundant geothermal activities,such as thermal spring,anthropogenic source processes and changes in meteorological conditions,regulate and affect Hg behavior in the study area.展开更多
CO 2 is the key gas of the greenhouse ones, the effect of its radiation on temperature ascent is 60% of the total greenhouse gases. The elevating CO 2 concentration influences to a great extent the future climate wa...CO 2 is the key gas of the greenhouse ones, the effect of its radiation on temperature ascent is 60% of the total greenhouse gases. The elevating CO 2 concentration influences to a great extent the future climate warming in a regional or global scale. Forest is the main part of carbon cycling in the land ecosystem.. Monitoring CO 2 absorption and emission in the forest ecosystem play a non\| fungible role in study on the global change. Gongga Mountain is located in the southeast margin of the Tibetan Plateau, and there exist intact vertical vegetation zonality, which is advantageous for measuring soil CO\-2 emission on each vertical forest zonality and researching the ecological factors of soil respiration.The east slope of Gongga Mountain develops 5 natural forest vertical zones from lower to higher altitudes: secondary forest, ever\|greened and deciduous broad\|leaved mixed forest, broad\|leaved and coniferous mixed forest, coniferous forest and alpine shrubs. Based on the two\|year’s measurement, the soil respiration of each forest averaged: 5 488, 6 344, 5 912, 4 176 and 3 864μmol CO 2/(m 2·s); the flux of soil CO 2 emission was arranged: 208 628, 241 169, 224 746, 158 752 and 146 891kg CO 2/(hm 2·d), respectively.展开更多
By testing soil organic matter (SOM) contents, soil water contents (SWC) within low suctions, and saturated infiltration rates of samples taken from east slope of Gongga Mountain of China, the enhancive effects of...By testing soil organic matter (SOM) contents, soil water contents (SWC) within low suctions, and saturated infiltration rates of samples taken from east slope of Gongga Mountain of China, the enhancive effects of SOM contents on SWC within low suctions and saturated infiltration rates were quantified. The simulated functions might be applied on regional experience forest-hydrology model. The improving function of protecting forest floor and increasing SOM contents on forest ecosystem hydrological effects were also embodied.展开更多
We selected a dark coniferous forest ecosystem of Gongga Mountain in the upper reaches of the Yangtze River as our research area to study the preferential flow and solute preferential transport by adding the tracers K...We selected a dark coniferous forest ecosystem of Gongga Mountain in the upper reaches of the Yangtze River as our research area to study the preferential flow and solute preferential transport by adding the tracers KNO3 and KBr to the self-made soil column equipment in different ways to examine density and volume changes of inflows and outflows of a mass input (impulse input) and a stable, well-distributed input (step input)). The results showed that this dark coniferous forest ecosystem of Gongga Mountain is a typical area of preferential flow and solute preferential transport, a process that can be classified into five parts. A great amount of solute was transported at high speed as the result of preferential flow in the soil and caused the density of the solute in both deep water and in groundwater to rise rapidly, which definitely increased pollution in the deep soil layer.展开更多
Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountai...Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.展开更多
基金This study was supported by the Knowledge innovation project of Chinese Academy of Sciences (KZCX2-Sw-319)
文摘Structural properties of forest soils have important hydro-ecological function and can influence the soil water-physical characters and soil erosion. The experimental soil samples were obtained in surface horizon (0-10 cm) from different subalpine forest types on east slope of Gongga Mountain in the upriver area of Yangtze River China in May 2002. The soil bulk density, porosity, stable infiltration rate, aggregate distribution and particle-size distribution were analyzed by the routine methods in room, and the features and effects on eco-environment of soil aggregation were studied. The results showed that the structure of soil under mixed mature forest is in the best condition and can clearly enhance the eco-environmental function of soil, and the soil structure under the clear-cutting forest is the worst, the others are ranked between them. The study results can offer a basic guidance for the eco-environmental construction in the upper reaches of Yangtze River.
基金Supported by the Youth Foundation of Chengdu University of Technology (2009QJ16)~~
文摘There are abundant excellent tourism resources in Gongga mountainous areas (Mount Gongga, also known as Minya Konka, the highest mountain in Sichuan, China), yet the development thoughts and management modes in this region are far away from the advanced level in other mountainous areas in China or abroad due to the insufficient knowledge about ecotourism. Generally speaking, tourism development in Gongga mountainous areas are limited by various problems such as lack of overall development plan, system support, brand image, financial support and environmental protection consciousness. In view of the present situation of tourism development in this region, sustainable development measures are proposed on the basis of ecotourism and sustainable development theories, including making ecotourism development plan for Gongga mountainous areas, improving transportation conditions, tourism infrastructures and accommodation facilities, training service and management personnel with professional ecological knowledge; establishing ecotourism product system of Gongga mountainous areas; carrying out ecotourism management, innovating management system, setting up ecological monitoring system, implementing scientific functional division of tourism sites, constructing environment capacity control system and disasters management system of mountainous areas, improving medical and mountainous assistance system. Natural conditions and economic development of Gongga mountainous areas are similar to those in western China, it is expected to provide theoretical basis and practical experience for developing the vast mountainous areas in western China through studying the sustainable tourism development of Gongga mountainous areas.
基金The Development Plan of the State Key Fundamental Research of China (973), contract No. 2000046807 and by Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-405)
文摘Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water regime of soil and connected with the growth of plant, the study combined the moisture percentage of soil with PF to research in quantity the interrelation between the moisture percentage and PF in different succession phases of subalpine dark coniferous forest in Gongga Mountain. The results showed that: (1) In the same PF value, the moisture percentage in humus horizon increased gradually with the devel-opment of the succession of the dark coniferous forest; The moisture percentage of over-mature forest was the highest and>mature forest>half-mature forest>young growth forest; (2) With the increase of soil depth, the soil bulk density increased and the moisture percentage decreased, but the difference in the percentage of moisture was not notable in different succession phases. (3) In different succession series, the vegetation affected the soil water characteristics by increasing the soil organic matter, improving the soil construction, receding the soil bulk density and enhancing the soil porosity; (4) The humus horizon of the dark coniferous forest soil has the highest water holding capability in this region.
基金funded by the Knowledge Innovation Program of Chinese Academy of Sciences(Grant No.KZCX2-YW-BR-21)National Science Foundation of China(Grant No. 41272200)
文摘Gongga Mountain, locates on the eastern edge of Tibetan Plateau of China, is the highest mountain in China except summits in Tibet. Only limited meteorological data on Gongga Mountain have been published so far. Here we present the meteorological records from two stations, Moxi Station (at 1,621.7 m above sea level (a.s.1.), 1992- 2010) and Hailuogou Station (at 2,947.8 m a.s.l., 1988-2010), on the eastern slope of Gongga Mountain. In the past two decades, the annual precipitation decreased while the annual mean temperature increased at Hailuogou Station. Both precipitation and temperature increased at Moxi Station. The precipitation variation on the eastern slope of Gongga Mountain is influenced by both East Asian Monsoon and Indian Monsoon, so that the precipitation concentrated between May and October. The temperature variation on the eastern slope of Gongga Mountain in the past two decades showed similar trends as that of the northern hemispheric and global. In the past two decades, the temperature increased o.35℃ and o.3℃/decade at Hailuogou Station and Moxi Station respectively, which was higher than the increase extents of northern hemispheric and global temperature. The most intense warming occurred at the first decade of 21St century. The winter temperature increased more at Hailuogou Station than at Moxi Station. A remarkable increase of temperature in March was observed with only a little precipitation at both high and low altitude stations.
文摘The distribution of soil organic matter (SOM) and nitrogen on Gongga Mountain was studied in this paper. The results showed that the content of SOM and nitrogen (N) of A horizon had an ascending trend with the increase of the elevation. The vegetation types distributed higher than the mixed broad-leaved and coniferous forest have the irregular trends. In the transitional zone vegetation such as mixed trees and treeline, the content of SOM and N is higher than other vegetation types. The distribution of SOM and N of A horizon is dependent on the synthetic effect of climate and vegetation types. The vertical distribution of SOM and N in soil profiles has the similar trends for all kinds of vegetation types, i.e., the content of A horizon is higher than that of the B and C horizons, which is the same to the distribution of dead animal and plant in soil. The soil C:N is between 7 and 25, which is relatively low comparing to the appropriate C:N of 25-30. The ratio of soil carbon to nitrogen (C:N)increases with the increase of the elevation, but its vertical distribution in soil horizons varies with different vegetation types. The N exists in SOM mainly in the form of organic nitrogen, and the soil C:N correlates significantly with SOM.
基金funded by the National Natural Science Foundation of China (Grant Nos. 41671016 and 41671262)
文摘Global climate change is having long-term impacts on the geographic distribution of forest species. However, the response of vertical belts of mountain forests to climate change is still little known. The vertical distribution of forest vegetation(vertical vegetation belt) on Gongga Mountain in Southwest China has been monitored for 30 years. The forest alternation of the vertical vegetation belt under different climate conditions was simulated by using a mathematical model GFSM(the Gongga Forest Succession Model). Three possible Intergovernmental Panel on Climate Change(IPCC) climate scenarios(increase of air temperature and precipitation by 1.8℃/5%, 2.8℃/10% and 3.4℃/15% for B_1, A_1B and A_2 scenarios, respectively) were chosen to reflect lower, medium and higher changes of global climate. The vertical belts of mountainous vegetation will shift upward by approximately 300 m, 500 m and 600 m in the B_1, A_1B and A_2 scenarios, respectively, according to the simulated results. Thus, the alpine tree-line will move to a higher altitude. The simulation also demonstrated that, in a changing climate, the shift in the vegetation community will be a slow and extended process characterized by two main phases. During the initial phase, trees of the forest community degrade or die, owing to an inability to adapt to a warmer climate. This results in modest environment for the introduction of opportunistic species, consequently, the vegetation with new dominant tree species becomes predominant in the space vacated by the dead trees at the expense of previously dominated original trees as the succession succeed and climate change advance. Hence, the global climate change would dramatically change forest communities and tree species in mountainous regions because that the new forest community can grow only through the death of the original tree. Results indicated that climate change will cause the change of distribution and composition of forest communities on Gongga Mountain, and this change may enhance as the intensity of climate change increases. As a result, the alternation of death and rebirth would finally result in intensive landscape changes, and may strongly affect the eco-environment of mountainous regions.
基金the National Key Basic Research and Development Program of China (973 plan: 2003CB415201)
文摘The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs (greenhouse gases) fluxes (CO2, NO and N2O) in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga Mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production (GPP) of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production (NPP) was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production (NEP) was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively.
文摘The Gongga Mountain of eastern Tibet Plateau is a representative of the alpine regions with high peaks and deep valleys. Climate change over the last thousand years has controlled the dynamics of glacier and debris flow occurrence, which resulted in substantial changes in the mountainous environment. The authors surveyed the community structure of primary forests in Gongga Mountain and forest succession processes in woodland plots. The changing features in the subalpine environment are discussed in this paper. Tree species and sizes between the glacier shrinking areas and debris flow fans in Hailuogou Valley are compared. The pioneer species that settle in debris flow fans and the glacier shrinking areas are Salix spp. and Populus purdomii. Abies fabri and Picea brachytyla are the climax tree species. The succession process of primary vegetation in Hailuogou (2700 ~ 3200 m) can be divided into four stages: Slash surface (20~ 200 yr) Salix-Populus seeding community (10 ~ 30 yr) Populus-Salix sapling community (30 ~ 100 yr) Populus-Abies mixed community (50 ~ 100 yr) Abies-Picea climax In a natural and undisturbed environment, trees compete for light, water and nutrients. Disaster disturbance in mountains is a very important driving factor for regeneration of woody plants. Repeated destruction of forests by glacier movement or debris flows generated additional forest gaps that allow young plants to grow. In this study the Gongga Forest Succession Model (GFSM) was developed for simulation of forest community succession processes on different scales in Gongga Mountain. A soil succession module was added to the GFSM model to simulate soil formation and chemical element change of woodland. In order to represent major features of forests in Southwestern China, many field works has been done to identify ecological parameters of various trees in the subalpine region. On the basis of simulation of tree life history, the GFSM combines forest succession with soil change in both material components and nutrition content. The Monte-Carlo method was applied to simulate random weather fluctuation and the uncertainty of tree death. These modeled processes agreed with the field investigation results in this region. The elevation distribution of different tree species was also simulated; and the results are consistent with field observations of ecological features of tree species. The modeling approach reflects well the succession dynamics of primary forests in Southwestern China. These results are very useful for improving the management policies and prediction technology for restoration and conservation of primary forests in Southwestern China.
基金the National Basic Research Program of China (973 Program) (2005CB422005)
文摘Distribution characteristics of soil organic matter(SOM) and total nitrogen(TN) were studied in different plant communities of the Yajiageng vertical belt in Gongga Mountain around the Dadu River banks. The results show: (1) the contents of SOM and TN of the plant communities gradually decreased with the following order: subalpine coniferous forest (3 027 m), subalpine meadow (3 873 m), coniferous broadleaved mixed forest(2 737 m), subalpine shrub(3 565 m) and treeline(3 564 m). (2) With soil profile depth increasing, the contents of SOM and TN gradually decreased. For different vegetation types, the contents of SOM and TN in sub-alpine coniferous forest were higher than that of other vegetational types. (3)The ratio of the content of carbon to the content of total nitrogen (Cc/CTN)WaS 13.5-27.6, which was relatively lower than the appropriate Cc/CTN of 25-30, and indicated that the soil in favor of the organic matter decomposed and nutrients released. Cc/CTN in the soil had no correlation with sea level altitude. However, its distribution in the soil x, aried with different vegetation types. (4) Nitrogen in SOM existed mainly in the form of organic nitrogen, and Cc/CTN in the soil was not obvious correlated with SOM and TN.
文摘Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury,their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However,only a few measurements of mercury,to our knowledge,have been done in ambient air over China. The highly-time resolved atmospheric mercury concen-trations have been measured at Moxi Base Station (102°72′E 29°92′N,1640 m asl) of the Gongga Alpine Ecosystem Observation and Experiment Station of Chinese Academy of Sciences (CAS) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A). Measurements were carried out with a time resolution of every 15 minutes. The overall average total gaseous mercury (TGM) covering the measurement periods was 4±1.38 ng·m-3 (N=57310),which is higher than the global background level of approximately 1.5~2.0 ng·m-3. The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally,it was found that the concentrations of TGM were highest in winter with 6.13 ± 1.78 ng·m-3 and lowest in summer with 3.17 ± 0.67 ng·m-3. There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters,such as temperature,saturated vapor pressure,precipitation,ultraviolet radiation (UV) and atmospheric pressure at the whole measurement stage,and the correlations varied seasonally. Our results suggest that the local or regional abundant geothermal activities,such as thermal spring,anthropogenic source processes and changes in meteorological conditions,regulate and affect Hg behavior in the study area.
文摘CO 2 is the key gas of the greenhouse ones, the effect of its radiation on temperature ascent is 60% of the total greenhouse gases. The elevating CO 2 concentration influences to a great extent the future climate warming in a regional or global scale. Forest is the main part of carbon cycling in the land ecosystem.. Monitoring CO 2 absorption and emission in the forest ecosystem play a non\| fungible role in study on the global change. Gongga Mountain is located in the southeast margin of the Tibetan Plateau, and there exist intact vertical vegetation zonality, which is advantageous for measuring soil CO\-2 emission on each vertical forest zonality and researching the ecological factors of soil respiration.The east slope of Gongga Mountain develops 5 natural forest vertical zones from lower to higher altitudes: secondary forest, ever\|greened and deciduous broad\|leaved mixed forest, broad\|leaved and coniferous mixed forest, coniferous forest and alpine shrubs. Based on the two\|year’s measurement, the soil respiration of each forest averaged: 5 488, 6 344, 5 912, 4 176 and 3 864μmol CO 2/(m 2·s); the flux of soil CO 2 emission was arranged: 208 628, 241 169, 224 746, 158 752 and 146 891kg CO 2/(hm 2·d), respectively.
基金This research was supported by the Knowledge Innovation Project of Chinese Academy of Sciences (KZCX2-SW-319).
文摘By testing soil organic matter (SOM) contents, soil water contents (SWC) within low suctions, and saturated infiltration rates of samples taken from east slope of Gongga Mountain of China, the enhancive effects of SOM contents on SWC within low suctions and saturated infiltration rates were quantified. The simulated functions might be applied on regional experience forest-hydrology model. The improving function of protecting forest floor and increasing SOM contents on forest ecosystem hydrological effects were also embodied.
基金the financial support provided by the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20060022006)National Natural Sciences Foundation of China (Grant No. 30471379)
文摘We selected a dark coniferous forest ecosystem of Gongga Mountain in the upper reaches of the Yangtze River as our research area to study the preferential flow and solute preferential transport by adding the tracers KNO3 and KBr to the self-made soil column equipment in different ways to examine density and volume changes of inflows and outflows of a mass input (impulse input) and a stable, well-distributed input (step input)). The results showed that this dark coniferous forest ecosystem of Gongga Mountain is a typical area of preferential flow and solute preferential transport, a process that can be classified into five parts. A great amount of solute was transported at high speed as the result of preferential flow in the soil and caused the density of the solute in both deep water and in groundwater to rise rapidly, which definitely increased pollution in the deep soil layer.
基金the National Natural Science Foundation of China(No.32270454)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0501).
文摘Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.