基于碳储存变化的海岸带生态系统修复策略——以海南岛东南海岸带为例

Coastal Ecosystem Restoration Strategy Based on Carbon Storage Change:A Case Study of the Southeast Coastal Zone of Hainan Island

碳达峰碳中和、国土空间生态修复、海域海岛可持续管理均是国家重大发展战略的重要内容。海南东南海岸带近年来因自然因素、人为干扰和全球气候变化的影响,生态系统破坏严重,碳汇功能明显下降。其生态质量的下降与海南自由贸易港和国家生态文明建设试验区的定位要求明显不符,基于碳储存的生态系统修复工作亟需开展。文章以海南岛东南海岸带为例,基于InVEST模型的碳储存模块,结合研究区2000、2010、2020年土地利用数据,估算研究区碳储量,划分“碳汇、碳源区”,评价其碳储存功能,识别近20年来研究区碳损失状况,明晰碳损失严重区域,划分生态修复功能区。结果表明:2000—2020年,研究区建设用地扩张明显,林草地面积削减;生态系统受到不同程度的破坏,碳储量持续下降,20年降低了0.11 Gt;碳储量低的区域沿着海岸带环线向内陆延伸,万宁市区域单位栅格碳密度值最低,三亚市区域单位栅格碳密度降低最多;碳源区面积始终大于碳汇区面积,碳储存功能为差和极差的区域面积分别为39.84和27.31 km^(2),主要分布于北部万宁市和乐镇、南部蜈支洲岛上方、西南部三亚市右侧等区域;基于碳损失和生态系统服务价值等级细分了自然修复区、人工辅助区、重建修复区和适度开发区,并针对性、差异化地提出包括退养还湿、岸线修复、湿地重建、加强监管等修复策略。

Carbon peak and neutralization,land space ecological restoration,and sustainable management of sea areas and islands are all important components of national development strategies.In recent years,owing to the impact of natural factors,human interference,and global climate change,the ecosystem of the southeast coast of Hainan has been seriously damaged,and its carbon sink function has decreased significantly.This decline in the ecological quality of the southeast coast of Hainan is inconsistent with the positioning requirements of the Hainan Free Trade Port and the National Ecological Civilisation Construction Pilot Zone.Thus,ecosystem restoration based on carbon storage needs to be urgently explored.Using the southeast coast of Hainan Island as an example,the carbon storage module based on the InVEST model,combined with the land use data of the study area in 2000,2010,and 2020,the carbon storage of the study area was estimated.The carbon sink and carbon source areas were divided,and the carbon storage function was evaluated.Over the past two decades,carbon loss in the study area has been identified,and areas with serious carbon loss were identified,with the ecological restoration functional area divided.The results showed that the ecosystem in the study area was damaged to varying degrees,decreasing by 1.11 Gt over 20 years.Traditionally,the area of the carbon source is always larger than that of the carbon sink.Areas with poor and extremely poor carbon storage functions were 39.84 and 27.31 km^(2),respectively.According to the superposition results of the carbon storage function and terrestrial ecosystem service value,four restoration units(natural restoration area,artificial auxiliary area,reconstruction restoration area,and moderate development area)were selected.In light of the different restoration areas and under the guidance of land space planning and the idea of carbon neutral and carbon peaks,ecological restoration strategies,including rehabilitation and restoration of wetlands,shoreline restoration,wetland reconstruction,and strengthening supervision,have been proposed in a targeted and differentiated manner.The research results have important reference value for strengthening the protection of the restoration area in the southeast coastal zone of Hainan,stabilizing the carbon storage capacity,reversing the trend of carbon loss,and realizing effective protection and restoration of the damaged ecosystem.Furthermore,the ecological service function and quality of coastal zones,and the marine ecological compensation mechanism,can be further improved.