摘要
内蒙古地区是我国草原生态系统比较重要的区域,植被净初级生产力(NPP)是生态系统碳源、碳汇的主要参数,研究NPP变化及其影响因子,对生态系统固碳能力的监测和预测有重要意义。本研究基于2000-2019年逐年MOD17A3–NPP产品数据以及降水、气温、相对湿度、光照时长、地表蒸散、高程、NDVI值等因子数据,研究内蒙古草原自然资源大区NPP的时空变化及其影响因子。通过Theil-Sen Median方法、Mann-Kendall显著性检验方法和Hurst指数分析方法,对2000-2019年内蒙古草原自然资源大区NPP值的时空变化和变化的可持续性进行分析,利用时空地理加权回归模型进行NPP变化的影响因子分析。结果表明:(1)在2000-2019年,区域NPP的平均值为208.96 g·(m^(2)·a)^(−1),呈上升趋势,平均每年上升约4.06 g·(m^(2)·a)^(−1)。在空间分布上,显著上升(|Z|>1.96)的区域占79.88%,包括极显著上升(|Z|>2.576)的区域占60.31%,显著区域占19.57%;显著减少的区域仅占0.15%,呈零星分布。(2)尽管大部分区域NPP值呈增加趋势,但未来呈持续增加的区域(呈上升趋势,H>0.5)约占19.45%,而潜在减少的区域约占74.15%(呈上升趋势,H<0.5)。(3)研究区NPP值变化与降水、相对湿度、NDVI值与NPP的关系主要呈正向相关关系,在2000年的回归系数平均值分别为0.368、0.218和0.402,在2019年的回归系数平均值分别为0.257、0.081和0.559;其中相对湿度和NDVI值对NPP值的影响从西南到东北有明显的线性变化趋势,降水对NPP的影响在该研究区西南和东北部分有些呈负相关,存在较强的空间聚集性和异质性。(4)NPP的变化与温度、光照时长和蒸散发呈现负相关关系,在2000年回归系数平均值分别为−0.027、−0.061和−0.020,在2019年回归系数分别为−0.145、−0.201和−0.001,光照时长和蒸散发对NPP值的影响由西南向东北有明显的线性变化趋势。
Inner Mongolia is an important region of the grassland ecosystem in China.Given that the net primary productivity(NPP)of vegetation is the main parameter of the carbon source and sink of ecosystems,studies of NPP variations and the factors that influence such changes are of great significance for the monitoring and prediction of the carbon sequestration capacity of different ecosystems.Therefore,this study was conducted to investigate the temporal and spatial variations in NPP of natural resources in the grassland region of Inner Mongolia and the factors influencing those changes,using annual MOD17A3–NPP product data from 2000 to 2019 as well as precipitation,temperature,relative humidity,light duration,surface evapotranspiration,elevation,and normalized difference vegetation index(NDVI)data.Through measures of the Theil-Sen median,Mann-Kendall significance level,and Hurst exponent,the temporal and spatial variations and sustainability of the NPP of natural resources in the grassland region of Inner Mongolia from 2000 to 2019 were determined.The factors influencing the NPP changes were analyzed using a spatiotemporal geographical weighted regression model.The results revealed the following:(1)From 2000 to 2019,the average regional NPP value was 207.72 g·(m^(2)·a)^(−1) and showed an upward trend.The average annual increase was approximately 4.06 g·(m^(2)·a)^(−1).(2)In terms of the spatial distribution,the areas with a significant rise(|Z|>1.96)accounted for 79.88%,In terms of the spatial distribution,the areas with a significant rise(|Z|>1.96)accounted for 79.88%,of which 60.31%showed a moderately significant rise(1.96<|Z|<2.576)and 19.57%accounted for an extremely significant rise(|Z|>2.576).The areas with a significant decrease in this parameter accounted for only 0.15%,showing a sporadic distribution.The persistence of the change in NPP value in the future was determined using the Hurst exponent.Although the NPP value of 94.01%showed an increasing trend,the regions with a continuous increase(showing an upward trend,H>0.5)accounted for approximately 19.45%,whereas those with a potential decrease accounted for approximately 74.15%(showing an upward trend,H<0.5).(3)With regard to the factors influencing the change in NPP in the study area,the correlation of the NPP value with precipitation,relative humidity,and NDVI was mainly positive,with the average regression coefficients being 0.368,0.218,and 0.402,respectively,in 2000 and 0.257,0.081,and 0.559,respectively,in 2019.The influences of the relative humidity and NDVI on the NPP value had an obvious linear change trend from southwest to northeast.The influence of precipitation on NPP was negatively correlated in the southwest and northeast of the study area,with strong spatial aggregation and heterogeneity.(4)Changes in temperature,light duration,and evapotranspiration mainly had a negative correlation with the NPP value,with the average regression coefficients being−0.027,−0.061,and−0.020,respectively,in 2000 and−0.145,−0.201,and−0.010,respectively,in 2019.The effects of light duration and evapotranspiration on the change in NPP showed an obvious linear trend from southwest to northeast.
作者
张子凡
熊茂秋
李福杰
刘晓煌
郝玉恒
邢莉圆
王新华
赖明
袁鹏程
ZHANG Zifan;XIONG Maoqiu;LI Fujie;LIU Xiaohuang;HAO Yuheng;XING Liyuan;WANG Xinhua;LAI Ming;YUAN Pengcheng(School of Geography and Information Engineering,China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China;Key Laboratory of Coupling Process and Effect of Natural Resources Elements,Beijing 100055,China;School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China;Urumqi Natural Resources Comprehensive Survey Center,China Geological Survey,Urumqi 830000,Xinjiang,China;Command Center for Natural Resources Comprehensive Survey,China Geological Survey,Beijing 100055,China;Yantai Geological Survey Center of Coastal Zone,China Geological Survey,Yantai 264000,Shandong,China)
出处
《草业科学》
CAS
CSCD
北大核心
2022年第12期2492-2502,共11页
Pratacultural Science
基金
塔里木河流域巴州北部沙漠盐渍化与生态恢复调查监测与评价(ZD20220144)。
关键词
NPP
时空变化
MK显著性检验
HURST指数
空间异质性
影响因子
时空地理加权回归模型
net primary productivity(NPP)
temporal and spatial variations
Mann-Kendall significance test
Hurst exponent
spatial heterogeneity
influencing factor
spatiotemporal geographical weighted regression model
作者简介
第一作者:张子凡(1999-),男,湖北汉川人,在读硕士生,研究方向为自然资源综合观测、地理信息系统开发,时空大数据分析。E-mail:1094861156@qq.com;通信作者:刘晓煌(1972-),男,山西平遥人,高级工程师,博士,研究方向为矿产勘查、矿床、基础地质、军事地质和自然资源综合观测研究。E-mail:liuxh19972004@163.com。
