【作者】 施文彧；

【导师】 王天厚；

【作者基本信息】 华东师范大学 ， 生态学， 2007， 硕士

【摘要】 长江口新生湿地一九段沙由上沙、中沙和下沙组成。处于水陆过渡地带,整个生态系统正处于发育过程,系统相对脆弱。在前期的研究过程中发现,九段沙湿地正遭受一系列的外来干扰,其中,于1997年在九段沙中沙和下沙地区进行的芦苇和互花米草引种实验带来的干扰较为严重,对九段沙湿地植被群落未来的演替趋势有非常大的影响。本文以九段沙湿地高等植物群落为研究对象,调查目前九段沙湿地3种主要植被的季节生长动态变化情况;并根据已有的研究基础,结合1998～2004年的遥感卫星资料和实地勘察,研究各植被分布面积变化和总生物量变化量,以此了解九段沙植被群落在引种实验以后8年间(1998～2005)的演替过程和发展趋势;分别研究3种主要植被的生态功能和经济价值,结合对九段沙湿地鸟类调查的结果,讨论“种青引鸟”工程对当地湿地植被群落和鸟类群落的影响,最终提出针对植被群落的初步管理建议。经过18个月连续的调查与观测和相关的研究以后,主要研究结果如下:九段沙湿地还在发育过程中,系统状态极不稳定;湿地高等植物群落结构单一,主要以芦苇群落、互花米草群落和藨草/海三棱藨草群落为主。分布在上沙的主要植被有芦苇、藨草/海三棱藨草。芦苇群落自上沙南部一直延伸到中部,在北部则是零星分布;上沙南部边缘生长着狭窄的海三棱藨草带,中北部地区则分布着成片的藨草和海三棱藨草群落。中沙与下沙之间的大潮沟两侧,曾于1997年人工引种芦苇和互花米草;目前,中沙大部分地区分布着芦苇群落、互花米草群落及两种植被的混合群落,海三棱藨草群落分布在外围;下沙高程比较低,外侧是光滩,内侧生长着大片的海三棱藨草,大潮沟南侧至中部地区分布有稳定的芦苇群落和互花米草群落。九段沙3种主要植被2004年秋季的分布面积分别为:芦苇1516.42hm2;互花米草1458.08hm2;藨草/海三棱藨草6662.87hm2。通过全年监测调查,结果表明芦苇的生长在春季为低潮,平均生物量为1221.61±974.21g/m2,夏季为高峰期,平均生物量为2336.49±1737.19g/m2;互花米草的生长在冬季最低(2083.98±11.87g/m2),入秋时达到一年内的最高水平(4554.87±889.02g/m2);而藨草/海三棱藨草群落全年的生长情况比较平均,仅在夏季略微旺盛一些(561.86±256.39g/m2);3种主要植物群落中,受季节和成长环境影响最小的是互花米草群落,其生长情况最好,单位面积生物量最大;随着互花米草群落面积的增大,它已发展为九段沙湿地总生物量最大的植被群落,04年秋季其地上部分总生物量达到3.033×107kg。按沙洲植被覆盖的面积变化情况看,下沙变化最为激烈,沙洲淤涨速度和植被扩散速度均最快,植被覆盖面积的年平均增长速度为38%左右;上沙最为平稳,增长速度为17%;中沙植被覆盖增长速度为22%,正向上沙的模式发展。3种主要植被群落中,互花米草群落扩散速度最快,占植被总面积比例从1998年不足1%上升至2004年的21.88%,且相对芦苇群落,其侵占藨草/海三棱藨草群落生长空间的情况更为严重:1998年至2002年间,互花米草在中沙和下沙侵占了约381.18hm2原先藨草/海三棱藨草群落的生长空间,而芦苇在九段沙全境内占据的空间约366.90hm2;藨草/海三棱藨草群落受互花米草排挤,总面积占植被面积比例从89.35%下降到55.36%,但由于其向外部低潮位地区扩展的速度较快(占据外围光滩面积为1459.62hm2),因此总面积依然保持快速增长;芦苇发展稳定,占九段沙植被总面积的22.76%,并在上沙地区形成单一、稳定的群落。九段沙3种主要植物群落均拥有一定的生态服务功能和经济价值:芦苇群落内共发现4目43种鸟类,以雀形目为主,它是雀形目鸟类重要栖息地:芦苇群落固定CO2的功能价值为944.25万元,有调节气候、净化水质、防风消浪等生态价值和造纸、入药等经济价值。通过样方对比研究发现收割可使芦苇群落直接增产150-230万元,因此建议实施类似“轮耕法”的隔年收割管理办法。互花米草群落固定CO2的功能价值为1235.95万元,是植被群落中最高的,也有加速演替、富集土壤金属、药用等一系列生态和经济价值,但群落内仅发现2目39种鸟类,G-F指数为0.29,是植被群落中最低的,不是鸟类的理想栖息地;且由于其扩展速度快,侵占土著种生长空间、排挤其生长,又建议对其扩散采取限制措施。藨草/海三棱藨草群落由于单位面积生物量比较小,因此固定CO2的功能价值相比另2种植被群落较低,为329.18万元;群落内发现6目104种鸟类,G-F指数为0.62,鸟类群落的多样性是植被群落中最高的;鉴于群落没有明显的退化迹象,扩散速度也属正常,因此没有特别的管理建议。目前,九段沙湿地生态系统的结构与功能均处于比较健康和理想的状态。今后,除了进一步加大加强保护的力度外,还应深入研究外来种互花米草对当地生态系统的影响,根据结果制定相应的科学管理办法,并研究如何合理利用湿地各种资源,在可持续发展思想的指导下管理九段沙湿地自然保护区,长期保持九段沙湿地生态系统的健康状态。更多还原

【Abstract】 Jiuduansha wetland is a newly formed intertidal wetland, covering three parts: Shangsha, Zhongsha and Xiasha. The ecosystem of Jiuduansha wetland is comparatively vulnerable because of its consistently growing. During the previous studies, some found that Jiuduansha wetland was enduring some external disturbance. The introduction of Phragmites australis and Spartina alterniflora in Zhongsha and Xiasha which took place in 1997 have brought serious and impactive influences on the future succession tendency of the vegetation communities in Jiuduansha.We investigated seasonal changes of the 3 main vegetation communities by monitoring their dynamic growth; Based on the present results, we studied the change of total area and biomass of all vegetation types with remote sensing data from 1998 to 2004 and survey on the spot to find out vegetation communities’ succession process and developing tendency in last 8 years after the introduction experiment. Furthermore, we studied the ecological functions and economic worth of the 3 vegetation types with results of avian investigation, and then we discussed what influence was brought to local vegetation and avian communities by the eco-engineering which called "planting to attracting birds". At last, primary management strategies aimed at vegetation were raised.After continuous investigation in 18 months, we get results as follows:The status of ecosystem in Jiuduansha is very unstable as it’s consistently changes. The simple vegetation communities consist of Phragmites australis, Spartina alterniflora （introduced species）, Scirpus mariqueter & S. triqueter. In Shangsha, P. australis, S. mariqueter & S. triqueter are the main vegetation types. P. australis dominates a majority of Shangsha from the south edge to central section. S. mariqueter & S. triqueter grow in north section mostly; in south section, they grow in long and narrow edges along the alluvion. In 1997, the introduction experiment took place in Zhongsha and Xiasha. Nowadays, P. australis or S. alterniflora or their mixed communities occupy most area of Zhongsha and S. mariqueter & S. triqueter grow in peripheral zone. Because of the lower altitude, it has a high percentage of mudflats in Xiasha. P. australis or S. alterniflora occupy the area from north to central section and S. mariqueter & S. triqueter also grow in peripheral zone. In fall 2004, the areas were occupied by 3 main vegetation communities as follows: 1516.42hm² by P. australis; 1458.08hm² by S. alterniflora; 6662.87hm² by S. mariqueter & S. triqueter.Through annual investigations, we understand that P. australis grows well in summer （biomass per m²: 2336.49±1737.19g/m²） and bad in spring （1221.61±974.21g/m²）; S. alterniflora grows to the top in autumn （4554.87±889.02g/m²） and in the lowest status in winter （2083.98±1184.87g/m²）. S. mariqueter & S. triqueter grow stablely, just a little higher in summer （561.86±256.39g/m²）. S. alterniflora gets least affects from season-change and growing condition and it holds highest biomass among the 3 main vegetation communities in Jiuduansha, with 3.033×10⁷kg in autumn 2004.Among the 3 alluvions, average annual speed of vegetation pervasion in Xiasha is 38%, much higher than in Shangsha （17% annually） and Zhongsha （22% annually）. S. alterniflora outspreads fastest; its percent of total vegetation area rose from less than 1% in 1998 to 21.88% in 2004. P. australis, S. alterniflora invade more growing space formerly occupied by S. mariqueter & 5. triqueter. From 1998 to 2002, 381.18hm² of S. mariqueter & S. triqueter area in Zhongshana and Xiasha were invaded by S. alterniflora, and another 366.90hm² in entire Jiuduansha was invaded by P. australis. The area occupied by S. mariqueter & S. triqueter community decreased from 89.35% to 55.36% because of the invasion form S. alterniflora. Although invaded and occupied, area of S. mariqueter & S. triqueter still grows up because it takes the place of the external mudflat-zone about 1459.62hm². P. australis community took 22.76% percent of the total vegetation area. It has formed a single and stable community in Shangsha.All vegetation types in Jiuduansha have some ecological functions and economic worth. In P. australis community, 43 kinds of birds of 4 orders were recorded in the research. The avian group is composed with Passeriformes mainly so that P. australis is very important habitats for Passeriformes birds. P. australis can bring 9,442,500 Yuan （RMB） through absorbing CO₂. It also has functions of the clime-adjustment, water purification, paper making, etc. Based on the characteristic of its growth, a management plan just like "furrowing in turns" applied in agriculture produce about 1,500,000～2,300,000 Yuan （RMB） in the practice. S. alterniflora has the highest value of absorbing CO₂ in three vegetation types, which can be calculated as high as 12,359,500 Yuan （RMB） , however only hold only 39 species of birds （G-F index: 0.29）, which kept lowest bird diversity among 3 vegetation communities. In a conclusion: S. alterniflora community could not provide a good habitat for avian communities.The value of CO₂- absorbing of S. mariqueter & S. triqueter community is about 3,291,800 Yuan （RMB）. There were 104 bird species in the sites of S. mariqueter & S. triqueter community. Its G-F index is 0.62, higher than the other two.Currently, both structure and functions of the ecosystem of Jiuduansha wetland seems to be in health condition generally. However, the conservation actions need to be undertaken in the future, particularly in the: scientific management on S. alterniflora community in this area. Furthermore, we need to understand how to use sustainably the wetland resources, and then maintain the healthy status of the native ecosystem of Jiuduansha directed by scientific view of sustainable development更多还原