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Impacts of permafrost changes on alpine ecosystem in Qinghai-Tibet Plateau

Science china Earth sciences 2006年第11期49卷 1156-1169页

作者： wang genxu1,3.,{2.,{3., Chinese Academy of {3., chengdu 610041, china 2. Cold and Arid Regions environmental and Engineering Research institute, Chinese Academy of {3., Lanzhou 73.000, china 3. Resource and environment School, Lanzhou University, Lanzhou 73.000, china institute of mountain {2. and {{3. Chinese Academy of Sciences Chengdu China Resource and environment School Lanzhou University Lanzhou China Cold and Arid Regions environmental and Engineering Research institute Chinese Academy of Sciences Lanzhou China

Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. The vegetation coverage, grassland biomass and soil nutrient and texture are selected to indicate the regime of alpine cold ecosystems in the Qinghai-Tibet Plateau. The interactions between alpine ecosystem and permafrost were investigated with the depth of active layer, permafrost thickness and mean annual ground temperature (MAGTs). Based on the statistics model of GPTR for MAGTs and annual air temperatures, an analysis method was developed to analyze the impacts of permafrost changes on the alpine ecosystems. Under the climate change and human engineering activities, the permafrost change and its impacts on alpine ecosystems in the permafrost region between the Kunlun mountains and the Tanggula Range of Qinghai-Tibet Plateau are studied in this paper. The results showed that the per- mafrost changes have a different influence on different alpine ecosystems. With the increase in the thickness of active layer, the vegetation cover and biomass of the alpine cold meadow exhibit a significant conic reduction, the soil organic matter content of the alpine cold meadow ecosystem shows an exponential decrease, and the surface soil materials become coarse and gravelly. The alpine cold steppe ecosystem, however, seems to have a relatively weak relation to the permafrost environment. Those relationships resulted in the fact that the distribution area of alpine cold meadow decreased by 7.98% and alpine cold swamp decreased by 2..11% under the permafrost environment degradation during recent 15 years. In the future 50 years the alpine cold meadow ecosystems in different geomorphologic units may have different responses to the changes of the permafrost under different climate warming conditions, among them the alpine cold meadow and swamp ecosystem located in the low mountain and plateau area will have a relatively

关键词： permafrost environment, alpine cold ecosystem, statistics relationship, climate change, impacts, Qinghai-Tibet Plateau.

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Influences of the degradation of swamp and alpine meadows on CO_2.emission during growing season on the Qinghai-Tibet Plateau

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Chinese Science Bulletin 2007年第18期52卷 2565-2574页

作者： wang JunFeng wang {2. wang yibo li yuanshou College of Earth and environment sciences Lanzhou University Lanzhou 730000 China institute of mountain {2. and {{3. Chinese Academy of Sciences Chengdu 610041 China Cold and Arid Regions environment and Engineering Research institute Chinese Academy of Sciences Lanzhou 730000 China

CO2.emission fluxes of two types of ecosystem, swamp meadow and alpine meadow, in the Fenghuo- shan region of the Qinghai-Tibet Plateau were studied by the static chamber-portable infrared chro- matographic method. The results showed that there was large difference in the CO2.emission fluxes between the two ecosystems and in the same ecosystem of different degradation degrees. CO2.emis- sion flux of the swamp meadow gradually decreased with increasing degradation degree, while that of the alpine meadow gradually increased with increasing degradation degree except in May. The CO2.emission flux of undegraded swamp meadow was 65.1%―80.3. higher than that of undegraded alpine meadow; and the CO2.emission flux of moderately degraded swamp meadow was 2..1%―67.5% higher than that of alpine meadow; but the CO2.emission flux of severely degraded alpine meadow was 14.3.―2..5% higher than that of swamp meadow. The soil moisture content and temperature in the upper 5 cm soil layer and above-ground biomass were significantly correlated with the CO2.emission fluxes and regarded as the main {2. factors to control the CO2.emission.

关键词：青藏高原沼泽草甸高山草甸生长季节二氧化碳释放量降解

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Study on the impact of vegetation degeneration to hydrology characteristic of the Alpine soil

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Research in Cold and Arid Regions 2011年第3期3卷 233-242页

作者： yibo wang {2. wu FuJun Niu {{3. wang HuiYan Cheng Laboratory of Frozen Soils CoM and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Gansu 730000 China College of Earth and environment Science Lanzhou University Lanzhou Gansu 730000 China institute of mountain {2. and {{3. Chinese Academy of Sciences Chengdu Sichuan 610041 China Lanzhou University of Technology Lanzhou Gansu 730000 China

Alpine soil infiltration process is an important part of the hydrological characteristics of alpine soil in permafrost. This research is carried out in the source region of the Yellow River where the permafrost is severely degraded, using various methods for choosing typical sample areas, and to experiment, study and simulate the soil water curve, soil saturated hydraulic conductivity, soil infiltration and soil moisture under different characteristics of degraded vegetation. The results indicate that the empirical equation θ=AS-B, proposed by Gradner and Visser, is very reliable in simulating the soil moisture curve; soil saturated hydraulic conductivity and soil infiltration are significantly different under different vegetation coverage： in the soil surface within 0-10 cm, the saturated hydraulic conductivity and infiltration intensity of Black Beach are the strongest; respectively, in soil layers below 3. cm, vegetation has almost no impacts on the saturated hydraulic conductivity, infiltration intensity and soil moisture content. Significant reduction of soil moisture occurs in soil surfaces with degraded vegetation. The more serious the degradation, the more water loss, and it can be up to 3..6% in the worst situation. Soil moisture of developed vegetation root systems in depths within 10-2. cm has the greatest impact on the soil environment, and the loss of moisture induces difficulty in the restoration of degraded meadows. Through a comparative study, the Kostiakov infiltration equationf（t） = at-b is more applicable for studies on the process of soil moisture infiltration of the alpine meadow in the source region of the Yellow River.

关键词： vegetation degradation alpine soil foil infiltration

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