互花米草入侵对滩涂湿地甲烷排放的影响

在浙江省台州市附近滩涂湿地设置3个不同互花米草入侵密度梯度,即仅有本土植物样地、互花米草与本土植物混生样地和互花米草单优群落样地,研究互花米草入侵对滩涂湿地CH₄排放的影响.结果表明: 3个样地CH₄排放通量为0.68～5.88 mg·m^-2·h^-1,CH₄排放通量随着互花米草入侵梯度的增加而显著升高,互花米草单优群落样地CH₄排放通量分别为本土植物样地和混生样地的8.7和2.3倍.互花米草入侵显著提高了产甲烷菌数量、产甲烷潜力、甲烷氧化菌数量、甲烷氧化潜力、植物生物量、土壤有机碳含量和土壤pH,降低了土壤全氮含量.CH₄排放通量与土壤全氮呈显著负相关,与产甲烷菌数量、产甲烷潜力、甲烷氧化菌数量、甲烷氧化潜力、植物生物量和土壤pH呈显著正相关.互花米草的入侵提高了滩涂湿地植物群落生物量和土壤pH,促进了产甲烷菌数量和产甲烷潜力,从而提高了滩涂湿地的CH₄排放.

Effects of Spartina alterniflora invasion on methane emission in coastal salt marsh.

To investigate the effects of Spartina alterniflora invasion on methane emission from coastal salt marsh, three S. alterniflora invasive levels were established nearby Taizhou City of Zhejiang Province, including native community, mixed community with S. alterniflora and native weeds, and mono-community of S. alterniflora. The results showed that the CH₄ flux in the three communities ranged from 0.68 to 5.88 mg·m^-2·h^-1, and CH₄ flux increased significantly with S. alterniflora invasion. CH₄ flux in the mono-community of S. alterniflora being 8.7 and 2.3 times as that in the native and mixed communities, respectively. S. alterniflora invasion increased significantly methanogens number, methane production potential, methanotrophs number, methane oxidation potential, plant biomass, soil organic carbon content and soil pH, but decreased significantly soil total nitrogen content. The correlation analysis showed that the CH₄ flux was positively related to methanogens number, methane production potential, methanotrophs number, methane oxidation potential, plant biomass and soil pH, but negatively related to soil total nitrogen content. Overall, our results suggested that S. alterniflora invasion improved plant biomass production and soil pH, resulting in the increases in methanogens number and methane production potential to further drive soil CH₄ emission.