【作者】 王睿照；

【导师】 张利权；

【作者基本信息】 华东师范大学 ， 生态学， 2010， 博士

【摘要】 生物入侵是全球变化的重要组成部分,对自然生态系统安全造成巨大威胁,已经成为生态学领域的研究热点之一。崇明东滩盐沼拥有独特的自然资源,底栖动物在滩涂湿地中发挥着承上启下的作用,连接初级生产和高级消费,是湿地生态系统中重要的动态中心。然而自20世纪90年代以来,外来植物互花米草在崇明东滩自然保护区内迅速扩散,对底栖动物群落结构和种类组成造成一定影响,因此系统研究外来植物互花米草入侵对崇明东滩底栖动物群落造成的影响,以及实施互花米草控制技术后对底栖动物的影响具有非常重要的现实意义和理论价值。本项研究于2007年-2008年间,在崇明东滩自然保护区开展了底栖动物群落的野外调查,通过分析底栖动物群落结构,构建正态化粒径谱,探讨了高程梯度和互花米草入侵历史对崇明东滩自然保护区内底栖动物群落可能造成的影响。此外,在崇明东滩生态修复示范样地,结合水位控制措施治理互花米草的物理试验,跟踪了示范样地内水位调控措施对大型底栖动物群落的影响。研究的主要结果如下：(1)崇明东滩底栖动物群落分析的结果表明,大型底栖动物群落的种类组成随着高程的变化而发生变化,大型底栖动物的分布则与高程和植被特征具有密切关系。随着高程的降低,底栖动物群落的多样性降低,生物量在中潮滩达到最高。底栖动物正态化生物量粒径谱(NBSS)斜率值随着高程的降低而降低。在相同高程下,互花米草群落中底栖动物粒径谱的斜率均小于土著植物群落和光滩生境,显示出互花米草群落中个体较小的底栖动物比例较高。(2)高程梯度和互花米草入侵历史对底栖动物群落造成影响的研究结果显示,大型底栖动物群落结构的特征随着高程梯度和互花米草入侵历史时间长短的变化而显著不同。大型底栖动物的生物量随高程的降低而降低,而小型底栖动物的生物量具有相反的趋势,随高程的降低而增加。NBSS的斜率随着高程梯度的降低而减小。与入侵历史较年轻的互花米草群落相比,入侵历史较久的互花米草群落中大型底栖动物的生物量显著的增高,小型底栖动物的生物量却明显降低。随着入侵历史的增长,互花米草群落中大型底栖动物的群落结构与本地物种芦苇之间的差异减小。入侵历史较年轻的互花米草群落与入侵时间较久的互花米草群落相比,底栖动物的NBSS斜率值更低。随着入侵历史的增加,互花米草群落中底栖动物的NBSS斜率值和本地物种芦苇群落之间的差异减小。NBSS方法能够有效的检测互花米草入侵对底栖动物群落可能造成的影响,为入侵物种的系统生态学研究提供更加广阔的视角,对于崇明东滩保护区和其他类似的被入侵的滨海湿地的物种保护和资源管理方面具有重要价值。(3)水位调控措施对大型底栖动物群落影响的结果显示,潮间带大型底栖动物的密度和生物量具有显著的季节性波动,实施持续水位调控措施样地中大型底栖动物的密度、生物量和丰富度指数均显著低于同时期对照样地。破堤排水后的恢复样地中,随着恢复时间延长,大型底栖动物密度、生物量和丰富度指数均有不同程度的恢复。研究结果表明,水位调控措施会对盐沼植被中大型底栖动物的密度、生物量和多样性产生负面影响,但这种影响在治理互花米草水位调控措施结束后可逐渐自然恢复。更多还原

【Abstract】 Biological invasion, as one of important component of global change, is threatening natural ecosystems and becoming one of the hot spots in ecological fields. Salt marshes in Chongming Dongtan, Shanghai possess the unique natural resources and face with a big challenge from the exotic plant invasion. Benthic community in the wetlands connects with primary production and consumption and plays a major role on nutrient cycling in salt marsh ecosystems. During the 1990s, an exotic Spartian alterniflora has spread rapidly. It is important to evaluate the impacts of S. alterniflora invasion on benthic communities of salt marshes and valuable to trace the effects of the physical measures to control the spreading of S. alterniflora on macrobenthic communities in Chongming Dongtan, Shanghai.This study investigated the distribution and community constructure of benthos in the salt marshes in Chongming Dongtan during the 2007 and 2008. The Normalized biomass size spectra (NBSS) were constructed to explore the S. alterniflora invasion on benthic communities. Moreover, trace the effects of managed waterlogging on macrobenthic communities. The main results of this study were summarized as follows:(1) Investigated the distribution of benthos and constructed the NBSS to explore the influence of plant type and evelation on the benthic communities. The results showed that the distribution and species composition of macrobenthos varied with the elevation and plant community charecteristics. The benthic diversity showed a decreasing trend along the elevation gradient. The slope of NBSS for the sampling sites decreased with the decreasing elevation. Compared with the native saltmarshes and bare mud habitat, Spartina alterniflora saltmarshes exhibitated the steeper slopes indicating the more samller individuals in the saltmarshes.(2) Explored the NBSS approach to evaluate the possible impacts of Spartina alterniflora invasion on the benthic communities along gradients of intertidal zones and invasion history of Spartina alterniflora at the nature reserve. The results showed that the characters of macrobenthic communities and the variation in macrobenthic communities described by the first two CCA axes revealed clearly the gradients of elevation and invasion history of Spartina alterniflora. The differences in the macrobenthic assemblages between the Spartina alterniflara marshes and the native Phragmites australis marshes decreased with increasing of invasion history of Spartina alterniflara. The macrobenthic biomass showed a decreasing trend while the meiobenthic biomass showed a reverse trend along the elevation gradient. The macrobenthic biomass at Spartina alterniflora marshes with longer invasion history was higher than that at recently invaded Spartina alterniflora marshes, while the meiobenthic biomass were lower. The slopes of NBSS for the sampling sites showed a trend of steeper slopes with decreasing of elevation and at the recently invaded Spartina alterniflora marshes than that at marshes with longer invasion history, while the differences between the native Phragmites australis marshes and the Spartina alterniflora marshes with long invasion history tended to be diminished. The NBSS approach could be effectively used to detect possible impacts of Spartina alterniflara invasion on the benthic assemblages. This study indicated also a potential for this approach to provide valuable insights into ecosystem ecology of invasive species, which could be very important for wetland biodiversity conservation and resource management in the Yangtze River Estuary and other such impacted areas.(3) Physical measures to control the spreading of an invasive plant Spartina alterniflora are important and necessary for biodiversity conservation at the Chongming Dongtan Nature Reserve. A field survey was carried out to trace the impact of managed waterlogging on the macrobenthic communities at a demonstration site. The results showed that managed waterlogging treatments had caused significant decreases in the density, biomass and diversity of macrobenthic community. Moreover, the community structure of macrobenthos was different drastically with the control site. After 12 month waterlogging and breaking the dike, the density, biomass and diversity of macrobenthos could recover gradually as compared with the control site. The result of multivariate analysis DCA ordination revealed that differences in community structure between the recovery site and the control site reduced gradually. The results from this study indicated that the control measure of managed waterlogging could have a negative impact on the macrobenthic community under saltmarsh vegetation, while such negative effects could be recovered by natural processes after ending the waterlogging treatment.更多还原