基于CASA模型模拟锡林郭勒草原净初级生产力

Simulation of Net Primary Productivity of Xilingol Grassland Based on CASA Model

随着气候变暖,生态环境发生了巨大的变化,植被净初级生产力(Net Primary Productivity, NPP)作为反映生态质量的重要指标被广泛应用于生态监测。为探究2001—2018年锡林郭勒草原生长季NPP对气候变化的响应,利用CASA模型对锡林郭勒草原NPP进行模拟。结果表明:过去18年,锡林郭勒草甸草原NPP显著性增加,4种植被类型的NPP年际变化较大;NPP东西差异明显,从东向西递减,与区域的植被类型高度吻合。温度和降水是导致NPP时空变化的主要因素,整体上NPP与温度呈显性著负相关(r=-0.629,p=0.05,N=18),与降水呈显著性正相关关系(r=0.913,p<0.001,N=18);对不同植被类型而言,降水和温度对NPP的影响也存在差异:草甸草原、荒漠草原受温度和降水量共同作用,而典型草原、沙地植被主要受降水量的影响,与温度的相关性较低,且不显著。从空间上看,研究区大部分地区受降水的影响,受温度影响的区域主要集中在研究区西部、中间北部以及东北地区,植被类型主要为荒漠草原、小部分典型草原及部分草甸草原。

With the change of climate, the global ecological environment has changed greatly. Net primary productivity(NPP), as an important index to reflect the ecological quality, has been widely used in the ecological monitoring. In order to investigate the response of NPP to climate change in growing season in Xilingol grassland from 2001 to 2018, the NPP of Xilingol grassland was simulated by CASA model. The results show that, in the past 18 years, the NPP in the grassland of the Xilingol meadow had the significant increase, and the interannual variation of NPP in the four types of vegetation was larger;the difference of NPP was obvious, decreasing from the east to the west, and was agreement with the vegetation type. The temperature and precipitation were the main factors causing NPP space-time variation, and the overall NPP was negatively correlated with the temperature dominant(r=-0.629,p=0.05,N =18), which was positively correlated with the precipitation significance(r =0.913,p< 0.001,N =18). For different vegetation types, the effects of precipitation and temperature on NPP were also different. Meadow grassland and desert grassland were affected by temperature and precipitation, while typical grassland and sandy land vegetation were mainly affected by precipitation, and the correlation with temperature was low and not significant. From the perspective of space, most areas of the whole area were affected by precipitation. The areas affected by temperature mainly concentrated on the desert grassland in the west, the typical grassland in the middle and the grassland in the northeast of the research area.