基于InVEST模型的钱江源国家公园生态系统碳储量研究

Study on carbon storage of ecosystem in Qianjiangyuan national park based on InVEST model

【目的】研究钱江源国家公园碳储量及其空间分布,分析国家公园建设过程中生态系统碳储量的变化特征及响应机制,探索国家公园建设中如何通过科学管理模式最大化其生态价值,为国家公园生态系统管理及减排增汇政策制定提供科学依据。【方法】基于InVEST碳储量模型,以遥感影像分类数据作为模型驱动数据,通过文献查阅确定钱江源国家公园各地类地上碳密度、地下根系碳密度、土壤碳密度和死亡有机物碳密度,并根据各地类年度累积碳储量作为修正因子,计算钱江源国家公园碳储量。【结果】森林是公园的主导地类,有林地在4个监测时间(2000、2010、2015和2018年)占公园面积的79.86%~81.57%。近20年(2000—2018年)公园各土地利用类型变化微弱。土壤碳储量和地上碳储量是公园总碳储量的主要构成,地下根系碳储量和死亡有机物碳储量占公园总碳储量比重较低。4个监测时间,经修正后的公园碳总量分别为4290511.08、4929477.63、5221423.97和5397444.70 t,森林生态系统碳储量是公园碳储量的绝对贡献者,占公园总碳储量的93.81%~95.56%。近20年公园生态系统碳储量持续增加。【结论】引入林木年度固碳增量对InVEST碳储量模型计算结果进行修正,可解决模型对碳循环过程进行简化,对土地利用变化微弱区域适用性低的问题。通过森林可持续经营优化林龄和树种结构,可增强森林生态系统的固碳能力。亦可通过农田退耕等方式调整土地利用结构,优化提升钱江源国家公园的生态系统服务功能。

【Objective】To study its carbon storage and spatial distribution in the construction process of the Qianjiangyuan national park,and to analyze the changing characteristics and response mechanism of ecosystem carbon storage,is of great significance to provide scientific basis for national park ecosystem management,and emission reduction policy formulation.【Method】Land use classification data were used as InVEST model-driven data to calculate the above-ground carbon storage,underground carbon storage,soil carbon storage and dead mass carbon storage in Qianjiangyuan national park.Carbon densities of different land use types as the essential parameters in InVEST model were determined through literature review.Then,annual cumulative carbon stocks were used as correction factors to calibrate the model simulation results.【Result】Forest is the dominant land use type in Qianjiangyuan national park.Proportions of forest land in the four monitoring time(2000,2010,2015 and 2018)were between 79.86%and 81.57%.Soil carbon storage and above-ground carbon storage are the main components of total carbon storage in the Qianjiangyuan national park,while underground carbon storage and dead mass carbon storage account oppositely.The total carbon stocks of Qianjiangyuan national park were 4290511.08,4929477.63,5221423.97 and 5397444.70t,respectively.Forest ecosystem carbon sequestration is the absolute contribution of the carbon stocks,ratios of forest carbon storage to the total regional carbon storage were between 93.81%and 95.56%.The land use patterns of Qianjiangyuan national park changed slightly from 2000 to 2018,while the carbon storage of ecosystem increased simultaneously.【Conclusion】The carbon sequestration increments were used as correction factors to rectify the results of the InVEST carbon storage model.In this way,the scientific and accuracy of carbon estimation results calculated by InVEST model improved significantly.The carbon sequestration capacity of forest ecosystem can be enhanced by protective forest restoration and sustainable forest management which optimize the age and tree species structures of forest ecosystem.It is also feasible that adjust the land use structure by returning farmlands to forests and other ways can favoring the improvements of ecosystem services.