【作者】 闫芊；

【导师】 陆健健；

【作者基本信息】 华东师范大学 ， 生态学， 2006， 硕士

【摘要】 河口潮滩湿地是海陆相互作用的重要场所，也是演替发生比较活跃的区域，潮滩湿地在淤涨的条件下有向陆演替的趋势。对于河口潮滩湿地演替的研究是目前湿地生态学领域里的热点问题，能为湿地的恢复和重建提供科学依据。 本文以长江口潮滩湿地——崇明东滩为研究基地，现场调查崇明东滩湿地植被类型、分析植被群落重要值、植被的生物多样性以及植物的生活型，实验室分析植被生物量以及含氮量，研究群落重要值、群落生活型、生物多样性、生物量以及氮容量在演替过程的变化。试图阐明潮滩湿地植被演替过程的特征。 主要研究结果如下： 1．潮滩植被生态演替的特征 潮滩湿地植被的成带分布反映了植被生态演替过程，在藻类盐渍带上缘生长着先锋物种海三棱藨草（Scirpus×mariqueter）带，随着高程升高，海三棱藨草逐渐被互花米草（Spartina alterniflora）和芦苇（Phragmites australis）所取代。随着高程升高，海三棱藨草的重要值逐渐下降，互花米草的重要值先升高再降低，芦苇的重要值则不断升高。海三棱藨草带和互花米草带植物生物多样性较低，芦苇带植物多样性明显升高，且出现一年生植物和地面芽植物。互花米草是一种外来物种，具有较强的竞争优势，是潮滩湿地潜在的优势种。 2．潮滩植被生物量的演替特征 植物生物量随着演替有增长的趋势，演替早期的先锋物种的生物量最低，作为演替较晚阶段出现的物种，芦苇和互花米草的生物量较大，互花米草做为外来物种，为潮滩湿地提供了巨大的初级生产力。 崇明东滩湿地植被地上生物量在生长季节内都表现出单峰变化，一般夏季（7、8月间）达到峰值。海三棱藨草地上生物量8月份达到最大，最大值为388.00g·m^-2。互花米草和芦苇地上生物量的最大值都出现在7月份，最大值分别为4244.40g·m^-2和4323.20g·m^-2。互花米草和芦苇的地下生物量显著大于海三棱藨草（p=0.0174），互花米草与芦苇两者之间差异性不显著（p=0.0683）。三种优势植物地上部分累积生长量的变化趋势是：互花米草最多，海三棱藨草最少。互花米草和芦苇差异不显著（p=0.458），互花米草和芦苇地上部分积累生长量显著大于海三棱藨草（p芦苇—海三棱藨草=0.002，P互花米草—海三棱藨草=0.004）。说明地上部分累积生长量随着演替呈增长的趋势。根据崇明东滩自然保护区建区时各种植物的面积计算，估计崇明东滩三种植物地上生物量累积量海三棱藨草为3571.6t，互花米草为5473.72t，芦苇为13862.83t。 3．潮滩植被含氮量和氮容量的演替特征 海三棱藨草作为先锋物种，其地上、地下部分都具有较大的单位含氮量，是更多还原

【Abstract】 Estuarine wetland is an important zone with interaction between land and ocean. In this special area, active ecological succession takes place. Research on ecological succession in estuarine wetland is the focal point in the studies of ecology, and would provide vital theoretical foundationf for wetland rehabilitation and reconstruction.In this paper, we sampled in Chongming Dongtan wetland, through on site survey and laboratory analyse, we studied the variation of importance value, life form, biodiversity, biomass and nitrogen concentration, tried to clarify characters in the process of vegetation succession. The main results are as follows:1. Ecological characters of salt marsh vegetation in successionFine-structured zonations refected succession process. Pioneer species Scirpus mariqueter Colonized and established near the barren area in low marsh, was gradually replaced by Spartina alterniflora and Phragmites australis along elevation. In the process of succession, importance value of Scirpus mariqueter decreased with the elevation, and which of Spartina alterniflora increased with the elevation in the beginning, then decreased near the dike. Importance value of Phragmites australis increased all the while. We could conclude that Scirpus mariqueter was the dominant species at low tidal marsh, Phragmites australis and Spartina alterniflora were dominant species at high marsh.In the area Spartina alterniflora and Scirpus mariqueter dominanted, biodiversity was very low, none other species existed, however, in the area Phragmites australis dominanted, biodiversity increased with hemicryptophyte, geophyte and therophyte plants appearing at the higher marsh.2. Temporal and spatial changes of vegetation biomass along successionBiomass increased with succession, biomass of early stage was low, as the representative of late stage, P. australis was much higher. As the colonizer, S. alterniflora possessed high biomass, provided huge productivity.All of three species had single peaks of aboveground biomass.The highest above ground biomass of S. mariqueter was observed in August, and those of S. alterniflora and P. australis were in July. Biomass of aboveground part ranged from24.98 g·m^-2to 388.00g·m^-2 for S. mariqueter, 137.26 g·m^-24244.40g·m^-2for S. alterniflora, and 115.49g·m^{-2 4}323.20g·m^-2 for P. australis. In a year long, the accumulate biomass increasement （ABI） of S. alterniflora was the highest, and in contrast, which of S. mariqueter was the lowest.ABI of S. alterniflora and P. australis were much higher更多还原