2001—2021年呼伦贝尔地区净生态系统生产力分布及其与气温和降水的关系

Distribution of net ecosystem productivity in the Hulunbuir region from 2001 to 2021 and its relationship with temperature and precipitation

选用2001—2021年呼伦贝尔地区MODIS NPP和气象站观测数据,计算该地区净生态系统生产力(Net Ecosystem Productivity, NEP),分析NEP时空分布及其与气温和降水的关系。结果表明:呼伦贝尔的年平均NEP为249.4 gC·m^(-2)·a^(-1),从呼伦贝尔大兴安岭中南部森林向两麓递减,呼伦贝尔草原西部NEP最小,且变异系数最大,生态环境相对脆弱。呼伦贝尔地区NEP以平均4.5 gC·m^(-2)·a^(-1)的速度增加,大兴安岭以东的林农交错带NEP增加较快,大兴安岭北部和呼伦贝尔草原东南部增加较慢。Hurst指数分析表明,未来呼伦贝尔大部地区的NEP变化趋势呈反持续性,不利于未来该地区固碳能力的提升。呼伦贝尔的草原、耕地以及大兴安岭东南麓森林NEP与生长季降水呈显著或极显著的正相关;草原地区NEP与生长季气温呈显著或极显著的负相关,大兴安岭火灾的灾后区NEP与生长季气温呈显著或极显著的正相关。

Utilizing MODIS NPP and meteorological station data from 2001 to 2021,this study calculated the net ecosystem productivity(NEP)in the Hulunbuir region and analyzed the spatial and temporal distribution of NEP and its relationships with temperature and precipitation.The results show that the annual average NEP in the Hulunbuir is 249.4 gC·m^(-2)·a^(-1),decreasing from the central and southern forests of the Greater Khingan Range to its flanks,with the western Hulunbuir grasslands having the lowest NEP and the highest coefficient of variation,indicating a relatively fragile ecological environment.The NEP in the Hulunbuir region has increased at an average rate of 4.5 gC·m^(-2)·a^(-1),with rapid increases observed in the forest-agriculture transition zone east of the Greater Khingan Range and slower increases in the northern part of the Greater Khingan Range and southeastern Hulunbuir grasslands.The Hurst index analysis suggests that future trends in NEP across most of Hulunbuir will exhibit anti-persistence,which is not conducive to enhancing the region′s carbon sequestration capacity.The NEP in Hulunbuir′s grasslands,croplands,and forests at the southeastern foothills of the Greater Khingan Range shows a significant or highly significant positive correlation with precipitation during the growing season.The NEP in the grassland areas has a significant or highly significant negative correlation with temperatures during the growing season,while the post-fire areas in the Greater Khingan Range show a significant or highly significant positive correlation with temperatures during the growing season.