红树林人工促进恢复过程中固碳速率与固碳机制

Mangroves have a very high potential for carbon sinks and play a huge role in the global carbon balance. Mangroves is a kind of special ecological forest in the coastal areas of Southern China, and a large number of artificial mangroves are being restored in our country. The research focused on how to maximize the ecological efficiencies in the process of mangrove artificial recovery (especially from the angle of carbon sequestration) was still scarce. Based on the scientific problems of carbon sequestration and its main influencing mechanisms in mangrove restoration process, we plan to conduct quadrat investigations and field long-term monitoring and control experiments in large-scale restoration of artificial mangroves on Qi’ao island, Zhuhai, Guangdong. We will present a systematic and quantitative study on different recovery technical measures, the biological and environmental factors, and the relative importance of each index on the carbon density and carbon sequestration rate in the mangrove recovery process with the Structural Equation Model(SEM) rising in recent years, in order to reveal the carbon sequestration mechanisms of vegetation and soil and their key limiting factors in the process of mangrove restoration. The results will provide a scientific basis for operating and managing the maximization of the mangrove recovery to the maximum carbon sequestration efficiency.

红树林具有极高的碳汇潜力，在全球碳平衡中发挥巨大作用。红树林是华南沿海地区特殊类型的生态公益林，我国正在进行大量人工恢复，而其恢复过程中如何获得生态效率的最大化，尤其如何从提高固碳效率角度去恢复，尚缺乏相关研究。据此，本项目围绕红树林人工恢复过程中如何固碳及其主要影响作用机制等科学问题，拟在广东省珠海市淇澳岛大规模恢复的人工红树林中，开展样方调查和野外原位长期监测控制实验，运用近年兴起的结构方程模型，系统地、定量地研究恢复技术措施、生物因子和环境因子，及其各指标对红树林恢复过程中的碳密度与固碳速率影响的相对重要性，揭示红树林人工促进恢复过程中植被与土壤固碳机制及关键限制因子。研究结果将为调控红树林恢复向固碳效率最大化提供经营和管理的科学依据。

项目主要以珠海市淇澳岛14种不同恢复类型的红树林作为研究对象，研究各类型红树林植被与土壤各自的碳密度及其固碳速率，揭示影响红树林恢复过程中固碳的主要因子，寻找最优红树林恢复类型，为合理配置红树林恢复树种提供依据。结果表明：.（1）8个不同树种红树林群落中，无瓣海桑群落植被生物量最大为355.54 t·hm-2，植被碳密度为159.99 t·hm-2，植被固碳速率为9.50 t·hm-2·a-1，固碳能力显著高于其他7个群落类型。.（2）8个不同树种红树林群落，土壤碳密度占碳密度的主要部分，除无瓣海桑群落外，各群落的土壤碳密度占总密度都大于70%。银叶树、秋茄、桐花树、木榄四个群落的植被碳密度处于20.27-25.29%，而老鼠簕、卤蕨、互花米草群落的植被碳密度较小，仅占总密度的0.40-1.26%。各群落凋落物碳密度极小，占总密度的0.7%。土壤固碳速率占固碳速率的主要部分，除无瓣海桑群落外，各群落的土壤固碳速率均占到总固碳速率60%以上，而互花米草、老鼠簕、卤蕨群落的土壤固碳速率则占总固碳速率的90%以上。无瓣海桑群落则表现为植被固碳速率高于土壤固碳速率，分别为60.85%、39.15%。.（3）6个不同林下恢复方式的红树林群落，植被碳密度占总碳密度的32.81-44.41%，土壤碳密度占总碳密度的54.77-66.85%，而凋落物碳密度占的比例很小，为0.34-0.87%。各群落土壤固碳速率占总固碳速率的48.17-62.42%，植被固碳速率占37.58-54.42%，除无瓣海桑+卤蕨群落外，其他5个群落的植被固碳速率均低于土壤固碳速率。.（4）无瓣海桑+木榄群落以及无瓣海桑群落固碳速率较高，银叶树、秋茄、木榄群落的总固碳速率相近，无瓣海桑+桐花树群落、桐花树群落、老鼠簕群落固碳速率较慢。.（5）植物种类组成、树龄、潮汐水位、底泥性状是影响红树林恢复过程中固碳能力的主要因子。