青藏高原高寒草原优势植物西北针茅对降水波动的响应

Responses of Dominant Plant Stipa krylovii of Alpine Steppe in Tebaten Plateau to Precipitation Fluctuation

通过分析农业气象站固定样地观察数据,研究了降水波动对高寒草原优势植物西北针茅和杂类草的影响。结果表明:西北针茅的丛数及其生产力随降水量增加而降低。相反,杂类草生产力随降水量增加而增加。西北针茅的丛数和生产力与土壤0~20cm温度呈显著负相关性;而杂类草的生产力与0~20cm土壤温度呈正相关。年降水的波动对西北针茅丛数及其生产力以及杂类草,特别是在降水极端偏低年份西北针茅的丛数及其生产力迅速增加,而杂类草生产力极低。这表明气候变化中的降水量年际波动是影响高寒草原优势植物西北针茅和杂类草生产力的重要驱动因素。

Based on the observation data of fixed sample plots at agricultural meteorological station,the effects of precipitation fluctuation on dominant species and weeds were studied.The results showed that the cluster number and productivity of Stipa krylovii was positive with 0-20 cm soil temperature.Conversely,cluster number and productivity of weed showed negative to 0-20 cm soil temperature.During the study period,precipitation amount showed an increasing trend,with greater fluctuation.The fluctuation of annual precipitation caused fluctuation of cluster number and productivity of Stipa krylovii,and weed biomass.In extreme drought years,the cluster number and productivity of Stipa krylovii presented rapid increased,while weeds productivity was very low.The results indicated that fluctuation of precipitation played an important role in driving community composition change in alpine grassland.