近20年重庆市主城区碳储量对土地利用/覆被变化的响应及脆弱性分析

土地利用/覆被变化（LUCC）是影响区域生态系统碳储量变化的重要驱动因素,探明碳储量对LUCC的响应及脆弱性,对区域实现“双碳”战略目标具有重要意义。以重庆市主城九区为例,运用InVEST模型研究了近20年主城区碳储量对土地利用转移的响应,采用潜在影响指数（PI）评估了该区域生态系统碳储量服务的脆弱性。结果表明：（1）2000—2020年间,主城区耕地面积减少743.29 km²,建设用地面积急剧增加773.48 km²。前10年土地转移面积6.05%,后10年转移13.98%,耕地转为建设用地是主要的土地转移类型。（2）近20年主城区碳储量累计减少5.78 Tg,其中建设用地侵占耕地是碳储量急速下降的主导因素。碳储量分布呈现“中部低—四周高”的空间格局。（3）近20年主城区均表现为碳源,土地利用程度指数提高14.73,PI指数为-2.50~ -2.59 Tg,均表现负面潜在影响,且2000—2015年间脆弱性不断恶化,2015—2020年间脆弱性有所缓解。研究结果可为区域生态可持续发展和未来土地利用管理政策制定提供参考,并为西部其他同类型山地城市提供借鉴。

Response and vulnerability analysis of carbon storage to LUCC in the main urban area of Chongqing during 2000-2020

Land use/cover change (LUCC) is an important driving factor that affects the carbon storage of regional ecosystems. Studying the response and vulnerability of carbon storage to LUCC is significant to the realization of the "dual carbon" goal. Taking the nine districts of Chongqing municipality as an example, the paper deeply explores the response of carbon storage to land use transfer and uses the Potential Impact Index (PI) to assess the vulnerability of ecosystem carbon storage services. The results show that: (1) Between 2000 and 2020, the area of cultivated land in the main urban area decreased by 743.29 km², and the area of construction land surged by 773.48 km². The land transfer area accounted for 6.05% in the first 10 years and 13.98% in the next 10 years. The conversion of cultivated land to construction land is the main land transfer. (2) In the study period, the carbon storage in the main urban area decreased by 5.78 Tg. The encroachment of cultivated land by construction land is the leading factor in the rapid decline of carbon storage. The distribution of carbon storage presents a spatial pattern of "low in the middle, but high in the surroundings". (3) Over the 20 years, the main urban districts were carbon sources. The land use degree index increased by 14.73, and the PI index ranged from -2.50 Tg to -2.59 Tg, both having negative potential impacts on the main urban area, and the vulnerability continued to deteriorate from 2000 to 2015. In 2020, the vulnerability eased. The results can provide references for the sustainable development of regional ecology and the formulation of future land use management policies, and for other similar mountainous cities in western China.