| 摘要: |
| 收集了研究区近20年以来的陆地卫星影像,结合以往实地调查资料,探讨了九段沙湿地优势植被群落多光谱遥感的分类方法,并对分类结果进行了现场校核,得出(1)多光谱遥感数据能够区分海三棱藨草与芦苇、互花米草植被群落;(2)季相变化的多光谱遥感数据可进一步区分芦苇与互花米草。分析了自20世纪80年代以来九段沙草滩及优势植被覆盖的时空变化,基本分为两个阶段80年代至1999年的自然演替阶段,2000年至今的人工干预阶段。结果表明(1)自然演替阶段。0m以上潮滩面积自然淤涨平均每年3.6km2;草滩平均每年增长1.2km2;芦苇仅出现于上沙的中部(除中沙1997年人工种植芦苇和互花米草外),其余均为海三棱藨草并占整体植被的80%以上,湿地自然演替速度相对较慢。(2)人工干预阶段。0m以上潮滩面积自然淤涨平均每年8.2km2,比自然淤涨速度快一倍以上;草滩平均每年增长7.86km2,增长速度远超过自然演替阶段;中沙人工引种的芦苇和互花米草群落扩散迅速,其覆盖占中下沙草滩的53.70%,其中互花米草扩散速度远快于芦苇,在中、下沙上占据了优势地位,而先锋植被海三棱藨草所占比例显著下降。 |
| 关键词: 九段沙湿地 遥感监测 时空分布 |
| DOI： |
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| 基金项目:上海市科技攻关计划“上海市滩涂资源可持续利用研究”项目,04DZ12049号;上海市科技攻关计划“九段沙湿地的动态监测、效应评价及后备土地资源的科学利用”项目,04DZ19305号。 |
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| REMOTE-SENSING ANALYSIS ON SPATIAL-TEMPORAL VARIATION IN VEGETATION ON JIUDUANSHA WETLAND |
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SHEN Fang1, ZHOU Yun-Xuan1, ZHANG Jie1, WU Jian-Ping2, YANG Shi-Lun1
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1.State Key Lab of Estuarine and Coastal Research,East China of Normal University,Shanghai,200062;2.Shool of Resources and Environmental Science,East China of Normal University,Shanghai,200062
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| Abstract: |
| Estuarine wetland has powerful ecological function and great biodiversity between land and ocean. Jiuduansha wetland, in 31°06′20″ – 31°14′00″ N, 121°53′ 06″ – 122°04′ 33″E, is a new-born wetland in Changjiang (Yangtze) River estuary formed between 1945 to 1958 by large amount of deposits unloaded from the river. The vegetation is in a primary stage, including mainly low plant and few higher ones in small diversity. In this research, data of field observation and spectrometry features of plant species were analyzed to the contrast of satellite imagery in different seasons. Identification and classification of dominant species were made with multi-spectral satellite data, showing that the plant S. cirpusmariqueter and Phragmites australis or Spartina alterniflora but P. australis and S. alterniflora can be identified with multi-spectral satellite imargery in blooming season. Superimposing two different season satellite images could pick out P. australis and S. alterniflora from the rest on the images.
In addition, evolution of the wetland since 1980 to the present was studied based on tidal flat deposition, the spatial-temporal variation in vegetation, and plant species. Two major phrases were divided: natural vegetation phrase from 1980 to 1999, and artificial vegetation phrase since 2000. In the natural phrase, the mean rate of tidal flat increased in area above 0 meter water depth was 3.6km2/a; and the mean rate of vegetation increase was 1.2km2/a. P. australis flourished only in the center of upper shoal, and S. mariqueter was the major occupant taking about 80% of the total. With the artificial interference, the tidal flat growth above 0 meter water depth increased to 8.2km2/a, more than doubled than the one in the natural vegetation phase; the mean growth rate of grass coverage was 7.86km2/a, much greater than that in the natural phase. Artificially planted P. australis and S. alterniflora spread swiftly on to the middle and lower parts of the shoals, taking 53.70% of the total vegetation area; and the pervasion of S. alterniflora was rapider than that of P. australis, being developing into a dominating species and gradually took space from pioneer P. australis. |
| Key words: Jiuduansha wetland, Remote sensing monitoring, Spatial-temporal distribution |
