不同土地利用情景下四平市生态系统碳储量时空演变

Spatio-temporal dynamics of territorial ecosystem carbon storage under different land use scenarios in Siping City

基于1990~2020年四平市土地利用类型数据,运用GeoSOS-FLUS模型,设定自然发展、耕地保护和生态优先三种情景,模拟不同情景下2030年四平市土地利用空间格局,同时结合InVEST模型定量分析研究区1990~2020年碳储量的时空分异特征,并探讨不同情境下土地利用变化对碳储量的影响,评估未来碳储量的潜力.结果表明:1990~2020年四平市耕地和林地分别减少了951.55km^(2)和357.54km^(2),且以1990~2000年间的降幅最大.草地和建设用地呈增加趋势,分别增加了702.97km^(2)和587.64km^(2).2030年在生态优先情景下,林地呈扩张态势,耕地有少量增加,在耕地保护情景下,耕地数量得到有效保障,而林地和草地有不同程度缩减.建设用地在三种情景下都呈现扩张的趋势,在自然发展情景下增长幅度最大.1990~2020年,四平市陆地生态系统的总碳储量及平均碳密度呈连续减少的势态,以1990~2000年的降幅最大,主要原因是该时段内土地利用变化以耕地的减少和建设用地的增加为主.四平市碳储量的高值区位于东部伊通满族自治县和铁东区,该区土地利用主要以林地为主.在研究时段内,总碳储量呈现减少趋势,且在1990~2000年内下降幅度最大,减少了约0.703×10^(7)t.在三种不同情景下,2030年研究区碳储量和平均碳密度呈现不同的发展趋势,生态优先情景能够有效的提高陆地生态系统的总碳储量和平均碳密度,而在自然发展和耕地保护情景下,两者都呈现下降趋势,耕地保护情景下的降低幅度相比自然发展情景明显减少.因此,研究区在未来土地资源规划中,应基于生态优先情景,保障耕地资源,优化土地利用结构,既保障耕地质量,又增加生态系统碳汇.

Based on the land use data of Siping City from 1990 to 2020,the Geo-FLUS model was employed to simulate the spatial patterns of land use for 2030 across three different scenarios:natural development,cultivated land protection and ecological priority.Additionally,the InVEST model was coupled to quantitively analyze the spatial and temporal variation of carbon storage from 1990 to 2020,as well the impact of land use change on carbon storage under different scenarios.The results showed that:(1)From 1990 to 2020,cultivated land and forest land in Siping City decreased by 951.55km^(2) and 357.54km^(2),respectively,with the sharpest decline between 1990 to 2000.Conversely,the grassland and built-up land use exhilited an increasing trend,expanding by 702.97km^(2) and 587.64km^(2),respectively.Under the ecological priority scenario in 2030,the forest land use was projected to expand,while the cultivated land would gradually increase.Cultivated land protection scenario ensured cultivated land availability but led to reductions in forest land and grassland.Built-up land use expanded across all three scenarios,most notably under natural development scenario.(2)Ecosystem carbon storage and average density in Siping City showed a continuous decline tendency from 1990 to 2020,with the steepest drop between 1990 and 2000.This decline was mainly due to decreased cultivated land and increased built-up land during that period.(3)Higher carbon storage value were observed in the eastern Yitong Manchu Automous and Tiedong area,characterized by forest land.Total carbon storage expressed a declining trend over the study period,decreasing greatly by about 0.703×10^(7)tons between 1990 and 2000.(4)Carbon storage and average carbon density in 2030 exhibited distinct trends across the three different scenarios.Ecological priority scenario led to an effective increase in both metrics for terrestrial ecosystem.Conversely natural development and cultivated land protection scenario yields declines,though the reduction under the cultivated land protection scenario was significantly lower than that under natural development scenario.Therefore,prioritizing ecological priority scenario in future land resource planning can ensure cultivated land resources,optimize land use structure,cultivated land quality,and amplify ecosystem carbon sequestration.