利用覆盖现代黄河三角洲1990～2013年逐年的24景 Landsat 遥感影像，开展了互花米草自引种至今的分布监测；根据互花米草随时间及分布区域的变化特征，分别从时间上和空间上分为4个时段和4个区域，开展了互花米草变迁分析；结合黄河每年的水沙量数据和气象数据等，分析了互花米草变化原因。结果表明，1）在时间上，互花米草总面积随时间出现较大波动。自1990年引种开始，总面积分别在1994年、2000年和2006年出现了3次较大幅度的减少，并分别于1992年、2003年、2005年和2012年达到了总面积的极大值，面积最大的1992年达到了约1138 hm2，最小面积值出现在2001年，仅有不到30 hm2；2）在空间上，互花米草分布范围不断扩大，表现为从东北方向西南方向扩展，但4个子区域的局部变化表明互花米草的引种并未有效遏制海岸的侵蚀后退，其中五号桩和孤东采油区东部的互花米草一直处于不断的面积减小和侵蚀后退中。另外，通过回归分析发现，互花米草发展和变迁与黄河水沙输送量有较大相关性。%In order to prevent the coastal erosion,the Spartina spp.was introduced to the Yellow River Delta in about 1990.Now it has become an invasive planting with the trend of explosive growth,which definitely does harm to the local ecological security.By using 24 Landsat remote sensing images which covered the Yellow river delta form 1990 to 2013, we monitored the spatial distribution year by year,and analyzed its dynamics in four sub-regions and four time periods according to the Spartina alterniflora distribution and dynamic characteristics.On this basis,we analyzed the reasons for the changes of Spartina alterniflora with the help of the annual water volume and sediment of the Yellow River observed in Lijin station.The findings are as follows.(1)The total area of Spartina alterniflora experienced dramatic changes from 1990 to 2013.Three significant decreases in area were found in 1994,2000 and 2006,respectively,and the maxima were achieved in 1992,2003,2005 and 2012,respectively.The largest area was about 1 138 hm2 in 1992,and the minimum appeared in 2001,less than 30 hm2 .(2)The spatial distribution of Spartina alterniflora expanded from the northwest to the southeast in the past 24 years.But the four sub-regional dynamics showed that the introduction of Sparti-na alterniflora communities was failed to curb the coastal erosion.
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