| 摘要: |
| 通过对2002～2003年度3个时相的Landsat TM图像进行监督分类处理,研究了盐沼植被的分布和变化。结果表明,目前盐蒿和大米草(Spartina anglica)占据的面积很小,年际变化不大,由于滩涂围垦的影响其面积还在进一步缩小。互花米草(Spartina alterniflora)成为优势种,占据了大部分的盐沼面积,向海蔓延显著,扩张的趋势还在持续,其覆盖面积的年增长速率可达18%。 |
| 关键词: 盐沼湿地植被 互花米草(Spartina alterniflora) TM图像 江苏海岸 |
| DOI： |
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| 基金项目:国家自然科学基金重点项目(40231010);教育部博士点基金项目(20020284007) |
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| Spatial and temporal variations in salt-marsh vegetation in Wanggang area, Jiangsu coast, based upon TM imagery analysis |
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| Abstract: |
| Wanggang area is a typical region of tidal flats. In the 1960s and 1980s, Spartina anglica and Spartina alterniflora were artificially introduced, respectively, to this area. Appearance of Spartina marshes changed the sedimentary environment of the tidal flats. Using Landsat-TM data, the vegetation change and consequent modifications to the geomorphology of the tidal flat system were analyzed. Firstly, field observation and sampling were undertaken to investigate the biological feature of the three main salt-marsh species: Suaeda salsa, Spartina anglica and Spartina alterniflora. Observations in the four different seasons show that summer represents a period of rapid growth. In autumn the plants have the highest biomass. Thus, 3 Landsat-TM images from 29 July 2002, 24 July 2003 and 28 October 2003 were used to map the vegetation distribution and annual change. Using the in situ data, spectral features obtained show that Bands 3, 4 and 5, in combination with field observations, contain sufficient information to distinguish the 3 different kinds of plants. Supervised classification using Bands 3, 4 and 5 with in situ calibration was performed to derive the distribution pattern of the vegetation in Wanggang areas. The result shows that: (1) Spartina alterniflora is expanding towards the sea, with a rate of several hundred meters per year; (2) in the upper part of the inter-tidal zone, Suaeda salsa and Spartina anglica are distributed near the sea dyke, but reclamation has reduced the area of these two kinds of marshes; and (3) from 2002 to 2003, the area covered with Spartina alterniflora increased by 18%. |
| Key words: salt-marsh vegetation Spartina alterniflora TM imagery Jiangsu coast |
