海岛建设引发的植被覆盖度变化的遥感分析

海岛生态脆弱、稳定性差,大规模的海岛开发使得原本脆弱的岛上植被生境面临更大的威胁,对海岛开发中的植被覆盖变化开展分析显得尤为重要。本文基于Landsat 5卫星和Landsat 8卫星的2001、2010和2014年的遥感影像,采用Gutmand和Ignatov提出的植被覆盖度计算模型提取福建平潭岛的植被覆盖度,并结合其土地覆盖变化信息,探究平潭综合实验区建设前后植被覆盖度变化特点及其原因。研究结果表明,3个时相的平潭岛植被覆盖度达中度以上的区域面积比例分别为86.00%、58.92%和71.16%,表明研究区整体植被覆盖状况良好。动态变化分析结果显示,2001-2014年研究区植被覆盖度总体呈下降趋势,其中2001-2010年植被覆盖度下降显著,下降区域面积比例高达53.95%;而2010-2014年岛上植被覆盖状况有较大改善,植被覆盖度增加区域面积比例达47.77%,这在一定程度上弥补了之前植被覆盖度大幅下降的影响,分析原因主要得益于平潭综合实验区建立后所采取的科学规划、进一步加大植树造林、逐步完善海岛绿地系统的植被建设与保护措施。

Remote Sensing Analysis of Fractional Vegetation Cover Change Triggered by Island Construction

The original ecological environment of island is fragile and lack of stability. Large-scale development and construction activities of island expose the vulnerable vegetation to a greater danger, which makes the detection and assessment of vegetation cover change especially necessary. Based on the remote sensing images of Landsat 5 and Landsat 8 in 2001, 2010 and 2014, the fractional vegetation cover (FVC) of Pingtan Island in Fujian Province was computed using the FVC calculation model proposed by Gutmand and Ignatov. Combining the FVC data with land cover change information, this study analyzed the variation in FVC of integrated experimental zone on Pingtan Island and explored its reason. The results showed that in 2001, 2010 and 2014, the middle and upper level of FVC in Pingtan Island accounted for 86.00%, 58.92%, 71.16%, respectively, which indicate that the overall vegetation in the study area is in good condition. The analysis of dynamic change showed that there is a declining trend in FVC from 2001 to 2014. The FVC decreased greatly by 53.95% from 2001 to 2010. On the contrast, the FVC rose by 47.77% from 2010 to 2014, which improved overall FVC condition substantially and offset the previously significant decrease of FVC. The comprehensive experimentation area was established in Pingtan Island. Greening projects and reasonable planning gradually improved the vegetation construction and protection of the island green land system. These reasons led to the increase of vegetation.