北部湾大风江口互花米草湿地有机碳储量的分布特征

Distribution characteristics of organic carbon stocks of Spartina alterniflora in Dafeng River Estuary,Beibu Gulf

互花米草被引入我国滨海地区后,经过多年的生长与演替,改变了潮间带原有生态系统的碳储量,而影响机制仍有待深入研究。为进一步探讨互花米草入侵后潮滩有机碳储量演变特征,该文以广西北部湾大风江口入侵约6 a的互花米草湿地为研究对象,分析了2018年8月、11月及2019年1月、3月采集的样品中有机碳及相关理化指标。结果表示:(1)互花米草植物年均地上碳储量为9.68 t·hm^(-2),高于地下根系的5.56 t·hm^(-2);(2)互花米草入侵湿地土壤碳储量显著高于互花米草植物本身,且不同季节中春季土壤碳储量显著高于其他季节;(3)土壤的C/N比值为3.53~9.67,表明互花米草入侵群落有机碳受海源的潮汐输入影响较大;(4)互花米草生态系统总碳储量与土壤碳储量之间呈极显著正相关关系,且季节性变化规律一致;(5)随着入侵时间的延长,互花米草生态系统中有机碳储量呈逐渐增加的趋势,表明互花米草入侵提高了光滩的有机碳储量,并能提高光滩的固碳能力。该文可为科学评价互花米草入侵对光滩碳储量的影响提供参考。

After Spartina alterniflora was introduced into coastal areas in China,the carbon storage of the original ecosystem was changed after years of growth and succession in the intertidal zone,but the influence mechanism remains to be further studied.In order to further explore the evolution characteristics of organic carbon storage in tidal flat due to S.alterniflora invasion,we took S.alterniflora wetland in Guangxi Beibu Gulf for about six years as the research object,and analyzed the organic carbon and related physical and chemical indexes of samples collected in August,November 2018 and January,March 2019.The results were as follows:(1)the average annual aboveground carbon storage of S.alterniflora was 9.68 t·hm^(-2),which was higher than that of underground roots(5.56 t·hm^(-2)).(2)The soil carbon storage of S.alterniflora invasion was significantly higher than that of S.alterniflora plant itself,and the soil carbon storage in spring was significantly higher than that in other seasons.(3)The C/N ratio of soil ranged from 3.53 to 9.67,indicating that the organic carbon of S.alterniflora invasion community was greatly affected by tidal input of sea source.(4)The total carbon storage of S.alterniflora ecosystem was significantly positively correlated with soil carbon storage,and the seasonal variation was consistent.(5)With the extension of invasion time,the organic carbon storage in S.alterniflora ecosystem showed a gradually increasing trend,indicating that the invasion of S.alterniflora increased the organic carbon storage and improved the carbon sequestration capacity in bare flat.This study provides reference for the scientific evaluation of the impact of S.alterniflora invasion on carbon storage in bare flat.