Under the background of the carbon peaking and carbon neutrality goals, the evolution of the spatiotemporal pattern of carbon storage has recently emerged as a research hotspot. The change in land use and land cover (LULC) is the primary driver of carbon storage changes. Understanding the spatiotemporal variations of LULC and carbon storage at the small scale of district and county level and proposing strategies to improve carbon sink, will contribute to the ecological conservation, restoration and sustainable development of districts or counties. With Yanqing District in Beijing as an example, we calculated carbon storage from 1990 to 2020 based on the InVEST model and used the PLUS model to predict LULC type changes under three scenarios (natural growth, ecological conservation and economic development) from 2020 to 2050. We further predicted the carbon storage and proposed mea-sures to improve carbon sink. The results showed that the key LULC change in Yanqing between 1990 and 2020 were the conversion of 88.9% of grassland to forest, 50.1% of farmland to forest, and 39.5% of cropland to impervious surface. The total carbon storage showed an upward trend, with an increase of 3.34×106 Mg. The spatial distribution of carbon storage presented "high in the northeast, low in the southwest, and high in the mountainous areas, low in the riverine areas." The increase in forest and the decrease in grassland were the main reasons for the increase and decrease in carbon storage, respectively. Between 2020 and 2050, the ecological restoration efforts under the ecological protection scenario increased, and the probability of other LULCs transforming into forest increased, resulting in a 5.8% increase in carbon storage, which had the highest increase and carbon storage under the three scenarios. High-value carbon storage areas were concentrated in the northeast, northwest, and south of Yanqing District, basically corresponding to the mountainous regions of Yanqing with high forest coverage, and the low-value areas generally corresponded to the plains with high development intensity and low forest coverage. We could implement comprehensive ecological protection and restoration measures, including forest and grassland ecosystem protection, water environment ecological restoration, farmland ecological restoration, to promote sustainable development in Yanqing District and to achieve the "dual carbon" goal.
近年来在碳达峰和碳中和的目标背景下,碳储量时空格局演变成为研究热点,而土地利用与覆被(LULC)变化是碳储量变化的关键原因。在区县级小尺度研究LULC与碳储量的时空演变并提出碳汇提升策略,有助于区县的生态保护修复与可持续发展。本研究以北京市延庆区为研究区,基于InVEST模型计算1990—2020年的碳储量,并采用PLUS模型分别预测2020—2050年3种情景(自然增长、生态保护、经济发展)下的LULC类型变化,并进一步预测碳储量,提出延庆区碳汇提升策略。结果表明: 1990—2020年间,延庆区主要的LULC转换趋势为88.9%的草地转向乔木林、50.1%的耕地转向乔木林、39.5%的耕地转向不透水面;碳储量总体呈上升趋势,增长了3.34×106 Mg,在空间分布上呈现“东北高西南低,山区高川区低”的特征,且乔木林的增加、草地的减少分别是碳储量升高和降低的主要原因。2020—2050年间,生态保护情景下的生态修复力度加大,其他LULC向乔木林转化的概率增加,从而带来碳储量增长5.8%,在3种情景中增幅最大且碳储量值最高。碳储量高值区域在延庆区东北部、西北部和南部出现集聚,基本对应森林覆盖率较高的延庆山区;低值区域基本对应开发强度较大、林木覆盖率较低的平原区。可从林草生态系统保护、水环境生态修复、农田生态修复等方面综合实施生态保护修复措施,推进延庆区可持续发展,助力延庆区实现“双碳”目标。.
Keywords: PLUS-InVEST model; Yanqing District; carbon storage; land use and land cover change; multi-scenario simulation.