西辽河流域植被NPP时空分布特征及其影响因素研究

为研究西辽河流域植被生长特征及受气候变化的影响,该文以2000年—2015年MOD17A3的年均植被净初级生产力(NPP)数据、植被类型数据、土壤类型数据以及气温、降水资料为基础,利用GIS和RS技术,分析了西辽河流域植被净初级生产力时空格局、演变特征及驱动因子。结果表明:(1)西辽河流域近16年来植被NPP总量呈波动增加的趋势,变化范围为156.89～260.90 g C·m^-2·a^-1,平均值为219.76 g C·m^-2·a^-1,空间分布呈“边缘高、中间低”的特征; 植被NPP变化斜率为-16.53～16.65,95.74%的区域NPP呈增加趋势。(2)不同植被类型的NPP总量大小排序为草原>栽培植被>阔叶林>灌丛>草甸>针叶林; 西辽河流域固碳的植被类型主要是草原、栽培植被以及阔叶林,固碳能力较强的为针叶林。(3)生长在棕壤、褐土和潮土的植被年均NPP较高,生长在栗钙土和风沙土的植被年均NPP较低。(4)16年间植被NPP增长主要受降雨影响。气候暖-湿化及生态建设工程的实施,促进了西辽河流域植被的生长。以上研究结果为后期流域生态环境治理提供了科学依据及数据支持。

Spatiotemporal distribution of vegetation net primary productivity(NPP)and its impact factors in the Xiliaohe Basin

This study aimed to study the characteristics of vegetation growth and the impact of climate change on the vegetation dynamics in the Xiliaohe Basin. The temporal and spatial variation of vegetation net primary productivity(NPP)in the Xiliaohe Basin were analyzed by GIS and RS technology by means of average annual NPP data of MOD17A3 dataset and the data of precipitation and temperature from 2000 to 2015. The results were as follows:(1)Vegetation NPP in the Xiliaohe Basin showed a fluctuating upward trend, ranging from 156.89 to 260.90 g C·m^-2·a^-1 and a mean value of 219.76 g C·m^-2·a^-1 from 2000 to 2015. Spatially, vegetation NPP in the middle part of the Xiliaohe Basin was lower than the edge sides. The changing slope of vegetation NPP ranged from -16.53 to 16.65 and 95.74% of the regions showed an increasing trend.(2)The total NPP among different vegetation types ranked as grassland > cultivated vegetation > broad-leaved forest > shrub > meadow > coniferous forest. The vegetation types of carbon sequestration in the Xiliaohe Basin were mainly grassland, cultivated plants and broad-leaved forest, and coniferous forest had strong carbon sequestration capacity.(3)Vegetation NPP was higher in the area coved by brown soil, cinnamon soil and moisture soil, and lower in the chestnut soil and aeolian soil.(4)Compared with temperature, precipitation was the main prominent contribution to the changing trend of NPP in the past 16 years. The warm-wet climate and the implementation of ecological construction projects promoted the growth of vegetation in the Xiliaohe Basin. These results provide a scientific basis and data support for the later basin ecological environment governance.