碳排放视角下武汉市土地生态风险时空格局演变

Spatiotemporal Evolution of Land Ecological Risk in Wuhan from the Perspective of Carbon Emission

[目的]探究土地利用碳排放对土地生态安全的不利影响,揭示不同因素的演变情况。[方法]引入碳足迹压力指数,并结合植被覆盖度、降水距平百分比指数、土壤侵蚀程度和土地利用混合度一同构建土地生态风险评价模型。使用熵权法确定风险指标权重并计算了综合风险指数。最后,利用空间分析方法,探究了武汉市2010年、2015年、2020年土地生态风险及空间集聚效应的时空演化规律。[结果]武汉市生态风险整体呈降低态势但幅度较小,各行政区风险指数差值大,中心城区植被覆盖度低、土地利用混合度低、碳排放压力高、土地生态安全状况堪忧;土地生态风险指数呈较强的空间集聚状态,冷热点集聚程度先增强后减弱,热点主要集中在中心城区和汉南区内。[结论]土地利用碳排放量的激增造成了土地生态风险的进一步加剧和风险来源的多样化,引入碳足迹压力指数能更全面地评估区域土地生态风险情况,为降低土地生态风险提供依据。

[Objective]The aims of this study are to explore the adverse effects of land use carbon emissions on land ecological security,and to reveal the evolution of different factors.[Methods]The carbon footprint pressure index in combination vegetation cover,precipitation distance level percentage index,soil erosion degree and land use mixing degree together was introduced to construct a land ecological risk evaluation model.The entropy weighting method was used to determine the weight of risk indicators and calculate the comprehensive risk index.Finally,the spatial analysis was used to investigate the spatial and temporal evolution patterns of land ecological risk and spatial agglomeration effects in Wuhan in 2010,2015 and 2020.[Results]The overall ecological risk in Wuhan City was decreasing but the magnitude was small,the difference of risk indices among administrative districts was large,the vegetation coverage in the central city was low,the land use mix was low,the carbon emission pressure was high,and the land ecological security was worrying.The land ecological risk index showed a strong spatial agglomeration state,and the degree of cold and hot spot agglomeration first increased and then weakened,and the hot spots mainly concentrated in the central urban area and Hannan District.[Conclusion]The surge in land-use carbon emissions has led to the further aggravation of land ecological risks and the diversification of risk sources,and the introduction of carbon footprint pressure index can more comprehensively assess regional land ecological risks and provide a basis for reducing land ecological risks.