降水波动对荒漠草原生产力的影响

在干旱、半干旱荒漠草原区,降水量波动对植被生产力有显著影响.这种影响表现在两个层次上,一是降水量年际间波动,二是年内降水分布格局.对阴山北麓内蒙古乌拉特后旗荒漠草原多年气象资料和植被生产力的分析发现:从1971-2011年降水量的年际波动特点来看,荒漠草原区最高降水年的降水量是最小降水年的3.76倍.从气象、实际和矢量年降水量3种统计表达方式与生产力的关系来看,反映年际降水波动和年内分布特点的矢量降水与植被生产力的关系最密切(R=0.9200,R_0.001=0.8010),回归方程F检验达到极显著.由于研究区植被组成以小半灌木和多年生草本为主,且年降水量大部分集中在5-8月,生长期内月降水量的累积效应明显,其中6-8月累计降水对植被生产力的影响最显著.

Impacts of Precipitation Change on Desert-grassland Vegetation Productivity

Desert-grassland vegetation productivity is significantly influenced by precipitation change, at either annual or seasonal scale, in arid and semi-arid region. In the period of 1971 to 2011, the maximum annual precipitation is 3.76 times of the minimum in the desert-grassland transitional region northern to Yinshan Mountain rightly at the northern part of Inner Mongolia of China. Vector precipitation is more significantly related to vegetation productivity (R=0.920, R_0.001=0.801)compared to long term annual precipitation and actual annual precipitation influence. Influence of the monthly accumulative precipitation on the productivity of grass and semi-bush dominated vegetation is more evident in the growing season and the influence in the period of June to August is the most significant.