广西北部湾不同入侵年份互花米草盐沼湿地土壤有机碳空间分布

Spatial distribution characteristics of soil organic carbon in Spartina alterniflora salt marsh in different invasive years along Beibu Gulf,Guangxi

自2011年以来,互花米草在广西壮族自治区北海市合浦县西场镇盐沼湿地从无到有,并且快速扩张,改变了盐沼湿地的景观,进一步影响了盐沼湿地的碳收支平衡。基于卫星遥感影像的方法确定互花米草的入侵年份,分析了2019年10月广西北部湾潮间带7条断面的互花米草盐沼湿地土壤中有机碳含量的空间分布,及其与互花米草生长年份的关系。结果表明:(1)互花米草盐沼湿地土壤中有机碳含量沿海岸线呈M型分布;(2)互花米草盐沼湿地土壤中有机碳含量的增加量随互花米草生长年份的增加而升高,互花米草生长5年时达到最大;(3)互花米草盐沼湿地土壤中有机碳含量随互花米草覆盖度的增大而升高;(4)互花米草盐沼湿地土壤中C/N平均值为12.5(>12),说明土壤有机碳受陆源的输入影响较大。

Spartina alterniflora has rapidly expanded from nothing at the salt marsh of Xichang Town,Hepu County,Beihai,Guangxi Zhuang Autonomous Region since 20ll,which changed the landscape of the salt marsh wetland and may affect the carbon budget of the salt marsh wetland further.Based on satellite remote sensing images,the invasion year of Spartina alterniflora was determined.Then the relationship between the spatial distribution of soil organic carbon and the growth year of Spartina alterniflora in 7 sections of salt marsh wetland along Beibu Gulf of Guangxi in October 2019 were analyzed.Results showed that:(1)the spatial distribution pattern of soil organic carbon(SOC)in Spartina alterniflora salt marsh shaped like“M”along the coast;(2)the content of soil organic carbon increased with the growth of Spartina alterniflora in this salt marsh wetland and reached the maximum after about 5 years of growth;(3)the content of soil organic carbon(SOC)in Spartina alterniflora salt marsh increased with the coverage of Spartina alterniflora;(4)the average ratio of C/N in the Spartina alterniflora salt marsh was 12.5(>12),indicating that the soil organic carbon was greatly affected by the terrestrial input.