北部湾典型入海流域植被CUE时空变化特征及驱动力因素分析

Analysis of temporal and spatial variation characteristics and driving factors of vegetation CUE in typical basin entering the sea in Beibu Gulf

植被碳利用效率(CUE)反映了植被生态系统在碳储存方面的效率,对于“双碳”政策背景下植被碳循环研究具有重要参考价值。本文基于MODIS数据、气象数据、DEM数据,采用趋势分析、变异系数、Hurst指数等方法,对北部湾典型入海流域2001—2020年植被CUE时空变化特征展开了研究。结果表明:①时间上,CUE年均值呈显著下降趋势(P<0.01),年际变化率均值为-0.003/a;年际CUE波动程度较小,整体上较为稳定。②空间上,北部湾典型入海流域CUE多年均值介于0.08~0.60之间,流域整体平均值为0.465。CUE年均值从高到低依次为,北仑河流域、钦江流域、江平江流域、防城江流域、茅岭江流流域、南流江流域、大风江流。③驱动力因素上,气温对北部湾典型入海流域植被CUE变化起主要控制作用,其次为高程和降水,土壤类型、坡度对植被CUE的驱动有限。

Vegetation carbon use efficiency(CUE),which reflects the efficiency of vegetation ecosystem in carbon storage,is of important reference value for the research of vegetation carbon cycle under the background of“dual carbon”policy.Based on the MODIS data,meteorological data and DEM data,the trend analysis,coefficient of variation and other methods are used to investigate the termporal and spatial variation characteristics of vegetation CUE in the Beibu Gulf watershed over the 2001—2020 periods.As shown by the results:①In terms of time,the average annual CUE presents a significant downward trend(P<0.01),with a downward slope of-0.003/a.The interannual CUE fluctuates slightly and is relatively stable.②Spatially,the average CUE of the typical basin into the sea of the Beibu Gulf ranges from 0.08 to 0.60,with an overall average value of 0.465.The average annual CUE,in descending order,are Beilun River Basin(0.492),Qinjiang River Basin(0.487),Jiangping River Basin(0.483),Fangcheng River Basin(0.477),Maoling River Basin(0.474),Nanliu River Basin(0.458),Dafeng River Basin(0.450).③From the perspective of driving factors,the average temperature plays a major role in controlling the change of vegetation CUE in the Beibu Gulf Basin,followed by elevation and rainfall.Soil type and slope have limited driving force on vegetation CUE.