中国西北半干旱区植被净初级生产力驱动力分析

Analysis on driving forces of net primary productivity of vegetation in semiarid region of northwest China

为探究半干旱区特殊的生态环境下净初级生产力(NPP)驱动因子及其贡献率,揭示半干旱区不同环境属性分区内各环境因子对NPP的驱动能力,以新疆伊犁河谷为研究区,采用逐步回归方法对NPP、NDVI、气象、地形、土地利用和土壤侵蚀数据进行统计分析,用于构建NPP环境因子模型。应用相关性分析探讨各因子与NPP间的相关性及各因子间的相关性,使用因子贡献率来阐明环境因子对NPP的驱动能力。研究表明,研究区NPP主导因子为NDVI、湿润指数和年均气温。半干旱区环境下NDVI、年均降水量、湿润指数、年均气温、干燥度与NPP有显著相关性(P<0.01)。不同湿润指数范围下,各环境因子对NPP的驱动能力差异明显,湿润指数小于0的区域NPP最强驱动因子为NDVI(P<0.01),而大于0的区域则为降水(P<0.01)。不同土壤侵蚀类型与土地利用类型间NPP主要贡献因子及贡献率差异显著(P<0.01),揭示了各环境条件下气象、NDVI与地形因子对NPP的驱动特点,为半干旱区NPP驱动力研究提供了科学依据。

In order to explore the driving factors of net primary productivity(NPP)and its contribution rate under the special ecological environment in semi-arid areas,and reveal the driving ability of environmental factors on NPP in different environmental attributes sub-regions in semi-arid areas,the Yili river valley in Xinjiang was taken as the study area.The stepwise regression method was used to analyze the data of NPP,NDVI,meteorology,topography,land use and soil erosion,and to construct the NPP environmental factor model.The correlation analysis was used to explore the correlation between each factor and NPP and the correlation between each factor,and the factor contribution rate was used to clarify the driving ability of environmental factors to NPP.Studies have shown that the dominant factors of NPP in the study area were NDVI,humidity index and annual average temperature.NDVI,average annual precipitation,moisture index,average annual temperature and dryness were significantly correlated with NPP in semi-arid region(P<0.01).Under different humidity index ranges,the driving ability of each environmental factor to NPP was significantly different.The strongest driving factor of NPP in the region with humidity index less than 0 was NDVI(P<0.01),while the region with humidity index more than 0 was precipitation(P<0.01).There were significant differences in the main contribution factors and contribution rates of NPP between different soil erosion types and land use types(P<0.01).The driving characteristics of meteorological,NDVI and topographic factors on NPP under various environmental conditions were revealed,which provided a scientific basis for the study of NPP driving force in semiarid regions.