克鲁伦河流域生长季有效温水组合对草原群落生物量的影响

The effect of temperature and precipitation during the growing season on the biomass of steppe communities in the Herlen Basin,northern China

利用克鲁伦河流域1958-2005年近半个世纪的逐日气温与降水量观测资料及23年(1983-2005)草原群落干物质产量资料,探讨了"有效积温"和"有效降水量"的变化规律及温水组合与草原群落生物量的相关性,得出近50年间>10℃的有效积温呈明显的上升趋势,其距平值年际间变化差异显著,具有明显的波动性。生长季降水量的增减虽无明显规律,但其距平值的变化呈上升趋势,时间尺度上波动性较大。1983-2005年期间,>10℃有效积温与有效降水量之间呈正相关关系(R=0.620 5),群落生物量与观测年>10℃的有效积温呈正相关性但不明显,与有效降水量之间呈显著的正相关关系(R=0.704 8,P<0.001)。群落生物量(Y)与有效降水量(X1)和>10℃有效积温(X2)之间的二元线性回归方程为Y=71.409+0.334 X1-0.020 X2,R=0.717(P<0.001)。合理的水热配置最有利于植被的生长,有效温水组合共同影响着半干旱区草原群落的生产力。

Regression analysis between dry biomass and the corresponding ＂effective accumulated temperature＂ or ＂effective accumulated precipitation＂ of 23 years was done using daily temperature and precipitation observa- tions from the past 48 years （1958-2005）. The effective temperature （〉10℃） showed an obvious upward trend but there were significantly different anomalies. There were no obvious variations of annual precipitation, but anomalies increased significantly （i. e. , differed significantly between years）. Effective precipitation during the growing season was an important resource and the effective accumulated temperature （〉10℃） and effective accumulated precipitation showed a positive correlation （R= 0. 620 5）. The biomass and effective accumulated temperature（〉10℃） did not reach significant levels, but effective accumulated precipitation showed a signifi- cant positive correlation. The relation of biomass with configurations of effective accumulated temperature and effective accumulated precipitation was Y= 71. 409＋0. 334X1-0. 020X2 and reached significant levels （P〈0. 001）. Suitable configurations of effective accumulated temperature and effective accumulated precipitation played the most important role in the growth of vegetation, while suitable configurations of temperature and precipitation affected productivity of steppe communities in semi-arid areas.