降水对高寒草甸草原植被盖度及地上生物量的影响

Effect of Precipitation on Vegetation Coverage and Aboveground Biomass in Alpine Meadow Grassland

降水量决定了植被生长的水分条件,是决定植被生产力的有效指标。本研究以甘肃省天祝藏族自治县高寒草甸草原为研究对象,研究多年采集的地上生物量数据与年度降水量,分析降水量对草原地上生物量的影响。研究表明:在高寒草甸生态系统中,春季降水是植物生长的重要影响因子,而夏季降水也是一个关键因素,一定幅度的增加或减少不会影响群落地上生物量积累;而降水量过大,由于气温较低,植被光热需求不能保障,群落地上生物量积累则会减少。通过分析,1~4月份降雨量60~70 mm之间,5~8月份降雨量在200~270 mm之间,高寒草甸草原牧草长势最佳,产草量较高。可以据此在未来气候变化背景下,通过预测年度降水量来预测年度草原生产力,为天然草原核定载畜量提供科学依据。

Precipitation determines the water condition of vegetation growth and is an effective indicator of vegetation productivity.In this study,the alpine meadow grassland in Tianzhu Tibetan Autonomous county of Gansu province was taken as the research object.The above ground biomass data and annual precipitation collected for many years were studied to analyze the impact of precipitation on the above ground biomass of grassland.The results show that in alpine meadow ecosystem,spring precipitation is an important factor affecting plant growth,and summer precipitation is also a key factor,a certain increase or decrease will not affect the community aboveground biomass accumulation.But the precipitation is too large,because the temperature is low,the vegetation light and heat demand can not be guaranteed,the biomass accumulation on the ground will be reduced.Through the analysis,the rainfall from January to April is 60-70mm,and from May to August is 200-270mm,the alpine meadow grassland has the best pasture growth and high grass yield.Based on this,the annual grassland productivity can be predicted by forecasting and analyzing the annual precipitation under the background of future climate change,which provides scientific basis for determining the livestock carrying capacity of natural grassland.