互花米草对中国海滨湿地土壤有机碳库的影响

How does Spartina alterniflora Affect the Soil Organic Carbon Pool of Coastal Wetlands in China

1979年互花米草(Spartina alterniflora)被引入中国用于促淤造陆,经过30余年的引种扩张,已经在中国海滨湿地潮间带形成了优势植被,并对中国海滨湿地土壤有机碳库产生影响,相关研究包括对土壤有机碳库规模、土壤有机碳库的输入过程、输出过程、土壤有机碳组分以及土壤碳库动态的影响等方面。文章从以上几方面概述了互花米草对中国海滨湿地土壤有机碳库的影响,并对以后的研究方向提出了建议,主要结论包括:不同区域互花米草对土壤有机碳库的影响有差异。互花米草在江苏沿海的光滩及碱蓬(Suaeda salsa)生态系统的扩张增加了土壤有机碳库存量,但是远低于其原产地美国的互花米草盐沼土壤有机碳含量;在福建红树林(mangrove)生态系统、芦苇(Phragmites australias)生态系统的入侵则减少了土壤有机碳库存量。互花米草定居扩张总体上促进了盐沼CO_2、CH_4、DMS和CS_2气体排放和卤代烷烃吸收。互花米草入侵对土壤有机碳库的效应受到生物与非生物因素的影响,包括入侵生态系统结构、环境物理因子变化、竞争物种的生物学特性、互花米草入侵年限等。未来需要在以下几个方面加强研究:扩大研究尺度进行跨区域定位比较研究;土壤有机碳库积累动态积累机制研究;土壤有机碳库与植物碳库输入输出耦合关系研究;对土壤碳库能力的变化进行定量综合评估;对全球变化的响应研究。

Spartina alterniflora was introduced into China in1979for promoting sedimentation and protecting seawall.It has become dominant in the intertidal zone of eastern coastal wetlands,and consequently posed significant impacts on the soil organic carbon pool of local wetlands in China.Current studies were focusing on the effects of S.alterniflora on soil organic carbon pool size,the input and output processes of soil organic carbon pool,the composition and fractions of soil organic carbon,the dynamics of soil organic carbon pool,etc.The present work summarized the effects of S.alterniflora on soil organic carbon pool in China's coastal wetland from the above aspects,and put forward suggestions on the future research direction.The key conclusions are as follows:The influence of S.alterniflora on soil organic carbon pool varied in different areas.The invasion of S.alterniflora to mudflat and Suaeda salsa saltmarsh in Jiangsu coastal wetlands promoted the soil organic carbon stock,yet remained lower than that of its native salt marsh in the US the invasion of S.alterniflora to Phragmites australias and mangroves saltmarsh in Fujian,Guangdong and Guangxi coastal wetlands decreased the soil organic carbon stock.Generally,the settlement and expansion of S.alterniflora increased the emission of CO2,CH4,DMS and CS2in coastal wetlands,whereas promoted the absorption to haloalkanes.The effectiveness of S.alterniflora invasion on soil organic carbon pool depended on both biotic and abiotic factors including the structure of the ecosystems invaded,the varying environmental physical parameters,the characteristics of the competing species and the invasion stages termed as time course.Further efforts need to make for comprehensive evaluation of the effects of S.alternifloraon soil organic carbon pool in China on the following aspects:to set study sites at multiple climatic zones and to conduct long period monitoring;the mechanism of soil organic carbon accumulation under invasion by S.alterniflora;the coupling relationship between plant carbon pool and soil organic carbon pool;calculation of the soil organic carbon sequestration capacity;and the response to global change.