高原鼠兔干扰下高寒草甸植物群落结构的时空动态特征

Temporal and spatial dynamics of plant communitystructure under the disturbance of plateaupika (Ochotona curzoniae)

摘要:

选择青藏高原东缘玛曲县高寒草甸栖息的高原鼠兔,以有效洞口数代表其干扰强度,选择3个干扰强度样地并连续3年调查了植物群落的变化。应用双因素方差分析、物种累积曲线和冗余分析研究了高原鼠兔干扰对高寒草甸植物不同物种、功能群和生活型的影响。结果表明:(1)随着高原鼠兔干扰强度和年份的增加,群落物种累积丰富度和物种累积速率均降低;(2)随着高原鼠兔干扰强度的增加,二裂委陵菜、白苞筋骨草、火绒草和蒲公英的重要值呈增加趋势,而高山嵩草、扁蕾和线叶嵩的重要值呈下降趋势。随着高原鼠兔干扰时间的增加,火绒草和白苞筋骨草的重要值呈增加趋势,而扁蕾、黄帚橐吾和球花蒿的重要值呈降低趋势;(3)随高原鼠兔干扰年份的增加,菊科、杂类草植物重要值逐渐增多,而禾本科和豆科植物重要值逐渐减少。随高原鼠兔干扰强度增大,菊科植物重要值增加,莎草科植物重要值减少。对于植物生活型而言,随高原鼠兔干扰强度和时间的增加,一年生和匍匐型植物逐渐增多,直立型和莲座型植物逐渐减少。

Abstract:

The effects of pika's disturbance on species,functional group and life form of plants in alpine meadow were studied by using the number of pika's burrows as an indicator of disturbance intensity (3 different disturbance intensities) in the eastern Tibetan Platea for 3 years.The two-factor variance analysis method,species accumulation curve and redundancy analysis were used to analyze the data.The results showed that 1) The accumulation richness and accumulation rate of plants had been decreased along the increase of intensity and time of disturbance;2) With the increase of disturbance intensity,the important values of Potentilla bifurca,Ajuga lupulina,Leontopodium leontopodioides and Taraxacum mongolicum increased,while the important values of Kobresia pygmaea,Gentianopsis barbata and Kobresia capillifolia were decreased.With the increase of the disturbance time,the important values of Leontopodium leontopodioides and Ajuga lupulina increased,while those of Gentianopsis barbata,Ligularia yellowbroom and Artemisia smithiiwere decreased.3) With the increase of disturbance time,the important values of Asteraceae and Forbs gradually increased,while the important values of grasses and Leguminosae decreased.With the increase of the disturbance intensity,the important value of Compositae increased and that of Cyperaceae decreased.With the increase of disturbance intensity and time,annual and creeping type plants gradually increased,while erect type and rosette form plants gradually decreased.