人类活动对额尔齐斯河流域碳储量的影响 postprint

Abstract: Carbon sequestration is among the main functions of terrestrial ecosystem services, and the carbonsequestration capacity of terrestrial ecosystems directly affects global carbon emissions and climate changeprocesses. Human activities directly influence land use and cover change, consequently affecting the carbonsequestration function of ecosystems. The terrestrial ecosystem services in dry and cold regions are morevulnerable and significantly impacted by human activities. Therefore, utilizing land use data from the Irtysh RiverBasin in the Altai Mountains from 2000 to 2020, the InVEST model was used to estimate and analyze the spatialdistribution of carbon stocks in the basin during different periods. Subsequently, the influence of human activitieson the spatial distribution of carbon stocks was discussed. The results show the following: (1) The main land usetypes in the basin are woodland, grassland, and unused land, and the land use pattern changed significantly from2000 to 2020. Cultivated land, urban and rural land, industrial and mining land, and residential land expandedcontinuously, increasing by 2619.35 km2 and 186.68 km2, respectively. Grassland and water areas initiallydecreased and then expanded, increasing by 4725.13 km2 and 33.47 km2, respectively. Meanwhile, forest land andunused land decreased continuously by 2328.88 km2 and 5237.76 km2, respectively. (2) During this period, thespatial distribution pattern of carbon stocks in the basin was similar and showed a zonal distribution. High-valueareas were distributed in high- altitude regions where grassland and woodland were clustered, while low- valueareas were distributed in low-altitude regions where unused land was clustered. In 2000, 2005, 2010, 2015, 2020the total carbon storage in the basin was 641.60 Tg, 645.78 Tg, 646.83 Tg, 650.28 Tg, and 665.91 Tg,respectively , with an annual growth rate of 0.95%, showing an upward trend. (3) The areas in the basin wherecarbon storage decreased or increased showed a spot- like distribution. Furthermore, carbon storage reductionmainly occurred through the conversion of grassland to unused land and cultivated land, with an average annualreduction of 58.81 Tg. The increase in carbon storage primarily resulted from the conversion of unused land intocultivated land and grassland, with an average annual increase of 64.82 Tg. From 2000 to 2020, the netsequestration of carbon storage exceeded the net release, indicating an increasing carbon sequestration capacity inthe Irtysh River Basin. Overall, the reclamation of land and grass due to human activities is the main reason forthe increase in carbon storage in the basin. However, it is necessary to coordinate the development and utilizationof water and soil resources, as this will guarantee not only an increased carbon sink but also the preservation ofthe carrying capacity of water and soil resources, ultimately achieving sustainable economic development in theIrtysh River Basin. The results of this study will help to promote the carbon cycle of the basin and the carbonsequestration capacity of the ecosystem, as well as provide a scientific basis for the establishment andmanagement of the basin carbon pool.