中国典型草原区气候变化及其对生产力的影响

The effects of climate changes on the productivity in the Inner Mongolia steppe of China

根据中国科学院内蒙古草原生态系统定位研究站(IMGERS)近20年的观测资料,利用Holdridge生命地带系统的气候指标:生物温度、降水、可能蒸散和可能蒸散率以及任继周等提出的草原综合顺序分类法的气候指标:>0℃积温、降水、湿润度,研究我国典型草原区的气候变化及其对净第一性生产力的影响。研究表明,近20年以来,中国科学院内蒙古草原生态系统定位研究站所在地区有变暖的趋势,冬季增温尤为明显。根据模型计算的净第一性生产力与在羊草样地实测的地上生物量值自1993年以后有明显的下降趋势。冬季增温使该地区春季干旱进一步加剧,并使典型草原的生产力下降。

Based on the observed data of the Inner Mongolia Grassland Ecosystem Research Station (IMGERS) of Chinese Academy of Sciences, the climate change and its effects on the productivity in Inner Mongolia steppe were investigated. Vegetationclimate indices of Holdridge's life zones system, such as: biological temperature (TB), precipitation (P), potential evapotranspiration (PET),potential evapotranspiration rate and indices of Ren Jizhou's grassland classification system:accumulation temperature(>0℃) (Σθ), precipitation (P), moisture index (K) were used for studying net primary productivity (NPP) models for natural vegetation. The results showed that the warming trend was observed on IMGERS in the recent 20 years, especially in winter. The observed values of the aboveground biomass of Leymus chinesis and model predicted values of the net primary productivity on IMGERS during 1982 to 1998 have decreased significantly since 1993. Temperature increases in the winter have aggravated the drought in the spring in this region, hence the grassland productivity is decreased.