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    黄土高原铁杆蒿群落分布格局对气候的响应

    Responses of distribution of Artemisia sacrorum community to climate in semi-arid and semi-humid areas of Loess Plateau

    • 摘要: 于2000-2009年采用野外调查与定位监测相结合的方法,研究黄土高原森林草原、典型草原和荒漠草原地带铁杆蒿群落分布和生长区域范围对气候变化的响应。结果表明:受温度等影响,铁杆蒿群落的适宜生长范围由东南向西北呈明显的地带性分布,即森林草原>典型草原>荒漠草原地带,群落密度分布格局分别为12.6、8.8和4.6株/m2,生殖枝数量分别为19、14和3株/丛;受降水梯度等影响,铁杆蒿群落的水平分布范围已由森林草原地带的建群种或优势种扩展到典型草原地带,并从伴生种上升为优势种,在荒漠草原地带的沟谷及沙丘周围常呈偶见种出现,并从年降雨量500~750mm的适宜区扩大到降雨量200mm范围的干旱区,铁杆蒿群落分布的海拔高度已由1900m扩展到2200m范围;在全球气候变暖背景下,典型指示植物——铁杆蒿群落受区域水热环境的影响,生态幅逐渐扩大,成为森林草原和典型草原稳定的地带性植被类型。

       

      Abstract: During 2000—2009, field survey and position monitoring were employed to find out responses of the distribution and growth region of Artemisia sacrorum community to climate in forest steppe zone, typical grassland zone and desert steppe zone of Loess Plateau. Affected by the temperature, suitable growth range of Artemisia sacrorum community presented obvious zonality distribution from sourtheast to northwest, namely, forest steppe zone> typical grassland zone >desert steppe zone, with population density 12.6 plants/m2, 8.8 plants/m2, 4.6 plants/m2respectively and reproductive branches 19 per cluster, 14 per cluster, 3 per cluster respectively. Affected by the rainfall gradient, the horizontal distribution of Artemisia sacrorum expanded from forest steppe zones to the typical grassland zone, which means it became the dominate species instead of the companion species. Also, it appeared as the occasional species on gullies and valleys and sand dunes in the desert steppe zone. Therefore, its optimal rainfall limits changed from 500-750mm to 200mm. In addition, Artemisia sacrorum extended from its optimal vertical elevation of 1900m to 2200m above sea level. Furthermore, the conclusion indicated that in the condition of global climate changes, Artemisia sacrorum as a typical indicting plant gradually widened its ecological amplitude and has become the steady vegetation type in forest steppe zone and typical grassland zone.

       

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