基于土地利用格局变化的生态风险与固碳功能评价——以河北省黄骅市为例

土地利用格局的变化会引起区域生态风险和固碳功能的变化。本文以河北省黄骅市为例,以1995年、2005年和2015年遥感影像为基础数据,基于土地利用格局变化构建生态风险指数,利用In VEST模型分析碳储量服务变化,并对二者进行相关性分析,以期为土地资源的合理利用提供科学依据。结果表明:1)1995—2015年,黄骅市主要土地利用类型为耕地、盐碱地和建设用地,对比2015年和1995年的结果发现,耕地、草地和建设用地破碎度和分离度增加,园地和盐碱地分离度和破碎度降低;园地和盐碱地损失度指数降低,而其他土地利用类型损失度指数增加。2)1995年、2005年和2015年黄骅市生态风险总和分别为12.58、10.32和11.10,生态风险区以较低风险区和高风险区为主,较低风险区面积逐渐增加且向南部集中,高风险区面积逐渐减少且向中部和东部海岸带集中。3)In VEST模拟结果表明,研究期间黄骅市碳储量呈现先上升后下降的趋势,1995年、2005年和2015年黄骅市的碳储量分别为2 387.05万t、2 491.51万t和2 028.86万t,3年的碳密度分别为107.63 t·hm~(-2)、112.34 t·hm~(-2)和93.16 t·hm~(-2),各土地利用类型碳储量的变化情况与各自面积的变化情况有较高的一致性。4)生态风险变化与碳储量服务变化的相关性分析结果表明,1995—2005年和2005—2015年二者相关性的决定系数分别为0.69和0.72(P0.01),呈显著负相关关系,表明生态系统服务变化在生态风险评价中应用的可能。基于土地利用格局变化对黄骅市生态风险和碳储量进行评价,对于其实现土地资源可持续利用和区域生态环境改善具有重要意义。

Evaluation of ecological risk and carbon fixation from land use change: A case study of Huanghua City, Hebei ProvinceE

The rapid development of social economy has had a profound impact on the change of land use pattern. Ecological risk assessment had played an important role in controlling ecological risk and realizing sustainable development. Changes in land use pattern will exert an effect on regional ecological risk and carbon sequestration. Combined evaluation of ecological service value and ecological risk assessment has become the new mode of studying ecological problems. This paper used Huanghua City in Hebei Province, China as a case study and remote sensing images for 1995, 2005 and 2015 as the basic data to analyze this pattern change. While ecological risk index was constructed based on the pattern of change in land use, InVEST was used to analyze the change in carbon storage. Finally, we analyzed the correlation between changes in ecological risk and carbon stock. The purpose of the study was to determine rational utilization of land resources for healthy development of ecological environment. The results showed that:1) cultivated land, saline land and construction land were the main land use patterns in Huanghua during 1995-2015. Compared 2015 with 1995, the degrees of fragmentation and separation in cultivated land, grassland and construction land increased, while the separation and fragmentation of garden plot and saline land decreased. While the loss index of garden plot and the saline land reduced, that of other land use types increased. 2) Total ecological risks of Huanghua City in 1995, 2005 and 2015 were 12.58, 10.32 and 11.10, respectively. During the study period, low risk and high risk area constituted the main risk areas. The area of the low risk gradually increased and was concentrated in the south. Then the area of high risk gradually decreased and was concentrated in the central and eastern coastal zones. 3) According to InVEST simulation results, the carbon storage in Huanghua City increased and then decreased eventually. In 1995, 2005 and 2015, total carbon storages in Huanghua were 23.870 5 million tons, 24.915 1 million tons and 20.288 6 million tons, with respective carbon densities of 107.63 t·hm^-2, 112.34 t·hm^-2 and 93.16 t·hm^-2. Change in carbon storage under each land use pattern was more consistent with change in the corresponding land area. 4) Correlation between changes in ecological risk and carbon stock was significant. The determinants of the correlation between changes in ecological risk and carbon stock in 1995-2005 and 2005-2015 were 0.69 and 0.72 (P<0.01), showing a significant negative correlation. It suggested that ecological risk assessment and ecosystem services valuation were concurrently assessable. This was one of the innovative points of the research. The assessment of ecological risk and carbon storage in Huanghua using change in land use pattern was important for the realization of sustainable utilization of land resources and improvements in regional ecological environment.