Climate changes and its impact on tundra ecosystem in Qinghai-Tibet Plateau, China
Climate changes and its impact on tundra ecosystem in Qinghai-Tibet Plateau, China
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DOI：
10.1007/s10584-010-9952-0
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发表时间：
2011-06
期刊：
影响因子：
4.8
通讯作者：
Genxu Wang;W. Bai;Na Li;Hongchang Hu
中科院分区：
文献类型：
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作者：
Genxu Wang;W. Bai;Na Li;Hongchang Hu
多年冻土区的高山生态系统对气候变化极为敏感。选取青藏高原多年冻土区长江、黄河水源地。利用1967年的景观生态学方法和航空照片，以及1986和2000年的卫星遥感数据，研究了1967-2000年期间冻土带生态系统范围和分布的时空变化。分析了气候变化与冻土带生态系统分布面积变化以及冻土带变化与冻土带生态系统的关系。利用统计回归方法建立了冻土带生态系统对气候和多年冻土变化综合作用的响应模型，估算了气候变化和多年冻土变化对冻土带生态系统退化的贡献。近45年来，区域气候呈明显变暖、变干的趋势，气温升高0.4~0.67℃/10a，降水相对稳定。由于气候持续变暖，地表热源强度平均每年增加0.45W/m2，地表土壤温度和气温差在4.1~4.5℃范围内增大，活动层内20 cm深度土壤温度在1.1~1.4℃范围内增加，高寒草甸和高寒沼泽草甸对多年冻土变化的响应比高寒草原更敏感。从1967年到2000年，高寒沼泽草甸面积减少了13.6-28.9%，高寒草甸面积减少了13.5-21.3%。从1967年到2000年，气候变化对高寒草甸和高寒沼泽退化的贡献率分别为58%-68%和59%-65%。气候变化和多年冻土变化的协同作用是青藏高原冻土带生态系统退化的主要驱动因素。
Alpine ecosystems in permafrost region are extremely sensitive to climate change. The headwater regions of Yangtze River and Yellow River of the Qinghai-Tibet plateau permafrost area were selected. Spatial-temporal shifts in the extent and distribution of tundra ecosystems were investigated for the period 1967–2000 by landscape ecological method and aerial photographs for 1967, and satellite remote sensing data (the Landsat’s TM) for 1986 and 2000. The relationships were analyzed between climate change and the distribution area variation of tundra ecosystems and between the permafrost change and tundra ecosystems. The responding model of tundra ecosystem to the combined effects of climate and permafrost changes was established by using statistic regression method, and the contribution of climate changes and permafrost variation to the degradation of tundra ecosystems was estimated. The regional climate exhibited a tendency towards significant warming and desiccation with the air temperature increased by 0.4–0.67°C/10a and relative stable precipitation over the last 45 years. Owing to the climate continuous warming, the intensity of surface heat source (HI) increased at the average of 0.45 W/m2per year, the difference of surface soil temperature and air temperature (DT) increased at the range of 4.1°C–4.5°C, and the 20-cm depth soil temperature within the active layer increased at the range of 1.1°C–1.4°C. The alpine meadow and alpine swamp meadow were more sensitive to permafrost changes than alpine steppe. The area of alpine swamp meadow decreased by 13.6–28.9%, while the alpine meadow area decreased by 13.5–21.3% from 1967 to 2000. The contributions of climate change to the degradation of the alpine meadow and alpine swamp was 58–68% and 59–65% between 1967 and 2000. The synergic effects of climate change and permafrost variation were the major drivers for the observed degradation in tundra ecosystems of the Qinghai-Tibet plateau.