闽江河口湿地枯落物分解及主要影响因子

以闽江河口湿地挺水植物本地种芦苇和入侵种互花米草的花和叶枯落物为研究对象,采用分解袋法分析其分解过程及主要影响因素.结果表明:立枯分解(0～90 d)是2种湿地盐沼植物重要的分解阶段,芦苇和互花米草的花和叶质量损失率分别为(15.0±3.5)％、(13.3±1.1)％和(31.9±1.1)％、(20.8±1.4)％.倒伏分解阶段(91 ～210 d),芦苇和互花米草的花和叶质量损失率分别为(69.5±0.6)％、(71.5±2.5)％和(76.8±1.9)％、(67.5±2.1)％.在立枯分解阶段,2种挺水植物枯落物的分解速率与C/N呈正相关,与N/P呈负相关,分解过程受到P的限制程度较大.倒伏分解阶段,枯落物C/N、C/P和N/P的影响降低,而大气温湿度、土壤水分、酸碱度、盐度和沉积物特性等的影响加大.不同分解阶段枯落物分解影响因子的差异主要与其所处的微域环境和潮汐因素有关.

Litter decomposition and its main affecting factors in tidal marshes of Minjiang River estuary,East China

By using litterbag method,this paper studied the decomposition of the leaf-and flower litters of two emergent macrophytes,native species Phragmites australis and invasive species Spartina alterniflora,and related affecting factors in the Minjiang River estuary of East China.In the decomposition process of the litters,the decay of standing litter(0-90 days) was an important period,and the loss rate of the flower-and leaf litters dry mass of P.australis and S.alterniflora was 15.0±3.5% and 13.3±1.1%,and 31.9±1.1% and 20.8±1.4%,respectively.During lodging decay period(91-210 days),the loss rate of the flower-and leaf litters dry mass of P.australis and S.alterniflora was 69.5±0.6% and 71.5±2.5%,and 76.8±1.9% and 67.5±2.1%,respectively.In standing decay period,the decomposition rate of the two plants litters was positively correlated with the litters C/N but negatively correlated to the litters N/P,and the litters P was an important factor limiting the litters decay.In lodging decay period,the effects of the litters C/N,C/P,and N/P decreased,while the environment factors(climate,soil moisture,soil acidity and salinity,and sediment properties) acted more important roles.The differences in the factors affecting the decay of the litters in different decomposition periods were mainly related to the micro-environment and tidal process for the two plant communities.