| 引用本文: | 张忍顺,沈永明,陆丽云,燕守广,王艳红,李加林,张正龙.江苏沿海互花米草(Spartina alterniflora)盐沼的形成过程.海洋与湖沼,2005,36(4):358-366. |
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| 江苏沿海互花米草(Spartina alterniflora)盐沼的形成过程 |
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张忍顺1, 沈永明2, 陆丽云1, 燕守广1, 王艳红1, 李加林1, 张正龙1
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1.南京师范大学海洋及滩涂研究所 南京210097;2.南京晓庄学院地理科学学院 南京210017
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| 摘要: |
| 选取江苏沿海的3个典型岸段,在2000—2001年进行了野外地貌沉积及植被调查,并进行了地形高程测量;选用了1985—2001年间7个时相的TM卫星影像资料,追踪了江苏互花米草盐沼形成的过程。结果表明,在移栽后的5—6年内,互花米草植被扩散缓慢,主要为立地扎根,走茎蔓延。在TM影像可以计量的规模上,互花米草植被在裸滩上的扩散可以分为三个阶段第一阶段为1993—1996年,随着面积逐渐增大,草仔数量明显增加,年扩展率逐渐扩大,到1996年,平均年扩展率已达30%。第二阶段为1996—1999年的3年间,互花米草人工盐沼的面积迅速扩大,年扩展率平均为43%。第三阶段为1999年以后,平均年扩展率迅速减小,为10%,预计还要减缓,最后,待原有潮滩生态位长满后,与滩涂自然淤长速率相应。 |
| 关键词: 互花米草 盐沼 江苏沿海 淤泥质海岸 |
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| 基金项目:江苏省农业资源开发局项目“条子泥促淤并陆工程实验研究”专项,1998年;国家自然科学基金资助项目,40401059号 |
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| FORMATION OF SPARTINA ALTERNIFLORA SALT MARSH ON JIANGSU COAST,CHINA |
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ZHANG Ren-Shun1, SHEN Yong-Ming2, LU Li-Yun1, YAN Shou-Guang1, WANG Yan-Hong1, LI Jia-Lin1, ZHANG Zheng-Long1
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1.Institute of Ocean & Coastal wetland Science Research, Nanjing Normal University, Nanjing, 210097;2.Department of Geography, Nanjing Xiaozhuang College, Nanjing, 210017
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| Abstract: |
| Spartina alterniflora was introduced from North Carolina, Georgia, and Florida in 1979 to China. A-l though the climate is much colder than its native habitat, the sediment and geomorphology of Jiangsu plain-mud-flat are fit for its growth. The total area of 137km2 of S. alterniflora salt marsh since the first planting in 1982 and 410km standard coastal line, which is 43% of total coast in Jiangsu, have been protected by S. alterniflora that has become the main species on Jiangsu tidal flat. Because the species is unique in its ecological system, so it formed a single-species vegetation on barren flat that once covered with other original vegetation species then washed away by coastal water agencies, which would greatly impact the coastal environment. So, this study was done to understand the formation of S. alterniflora salt marsh on coast of Jiangsu, China.
To trace S. alterniflora’s growth history, TM satellite images were analyzed. Specifically, maps of seven phases, 1985, 1988, 1993, 1995, 1997, 1999 and 2001, were used. For accurately reading and distinguishing Jiangsu coastal vegetation types, boundaries, areas, and ecological conditions, were studied in geomorphology, sedimentology, plant community, etc, in tidelands of Badou, Wangzhu and Dongchuan polders in Dongtai and Dafeng counties between September 2000 and January 2001. In order to provide reliable ground information for analyzing satellite images, measurements of elevations of three transects together with topography and vegetation distribution were performed.
The results show that, S. alterniflora from USA has been good to their new environment in Jiangsu coast. In over 20 years, total area of 137km2 of S. alterniflora has formed on bare flats lower than native marsh in elevation. It functions as a new measure of reclamation in Jiangsu salt marsh to broaden the wetland vegetations. S. alterniflora zone along Jiangsu coast occurs on higher part of upper intertidal zone, whereas the most seaward clumps may approach mean tidal water. Its elevation is lower than that of native wetland marsh, and its coverage does not overlap with original salt marsh vegetation. Once this newcomer succeeds in rooting, it propagates very well.
In the first several years (1987–1993) after transplanting, because of relatively large interval among vegetable plains, S. alterniflora was brought up and expanded to open flat until scattered grass tract joined together and become recognizable on TM images.
Based upon recognizable scale of TM satellite images, S. alterniflora expanding process on barren mudflat can be divided into 3 phases. The first phase (1993–1996), it expands slowly. In terms of sediment area accretion and seedlings growth, the annual expansion rate reached 30% by 1993. The second phase is between 1996 and 1999, the coverage increased rapidly at annual expansion rate of 43%. And the third phase is after 1999, in which the rate rapidly reduced to only 10%. It is estimated that it will further decrease to accommodate the rate of mudflat development after 2001.
In the areas downstream the river month tidegates, spreading of S. alterniflora along the shore was slowed down. However, the seeds can still find their way of dispersing. Uncoalesced grass patches of S. alterniflora creeped across large tidal creeks. The tidal flats soil with low contents of clay, organic matter but high wave energy can also develop and expand by the clump joining. If a half spreading rate were taken, this grass would still be able to spread all over the upper part of upper tide zone in Tiaozini area in about ten years. The species would play an important role in future in wetland preservation in China. |
| Key words: Spartina alternif lora, Salt marsh, Jiangsu coast, Muddy coast |
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