修筑海堤后光滩上红树林的形成与空间扩展——以广西珍珠港谭吉万尾西堤为例  

Establishment and Expanding of Mangrove Forest After Construction of the Seawall—A Case Study of Tahji-Wanwei Seawall in Pear Bay, Guangxi

作　　者：李春干[1] 周梅[2] 

机构地区：[1]广西大学林学院,广西南宁530004 [2]广西大学计算机与电子信息学院,广西南宁530004

出　　处：《湿地科学》2017年第1期1-9,共9页Wetland Science

基　　金：国家自然科学基金项目(41166001);中央财政林业科技推广示范资金项目(GXTG200904)资助

摘　　要：围填海是红树林减损的主要驱动力之一,但在某些原无红树林分布的区域,修筑海堤后出现了红树林。以在开阔的海域中建设的防城港市珍珠港谭吉万尾海堤为研究区,利用7期中高分辨率遥感影像(基准年分别为1960年、1989年、2001年、2007年、2010年、2013年和2015年)数据和2016年实地调查资料,分析1969年海堤建成后无明显破坏性人为干扰状态下红树林斑块的形成过程和空间扩展动态。研究结果表明,海堤竣工12 a后,即1981年出现了白骨壤(Avicennia marina)林,至1989年,白骨壤林发展成长640 m、平均宽度为25 m的带状斑块(1号斑块);1989~2001年出现了3个新斑块,分别形成于1989年、1993年和1995年;2013~2015年又新增了2个斑块,分别形成于2011年和2013年;海堤上的红树林面积由1989年的1.62 hm2增加至2015年的19.71hm2;红树林面积在早期迅速增加,2007年后,其年平均增加速率逐期减小;在1989年、2001年、2007年、2010年、2013年和2015年的5个监测期内,1号斑块的内边界保持稳定,外边界平均每年向海扩展1.4~6.0 m,表现为早期扩展速度慢、后期快的趋势;红树林斑块空间范围变化以扩张为主,伴随着局部地段的萎缩和破碎化。红树林斑块形成和发展的机制可能是修筑海堤后珍珠港成为了一个漏斗状海湾,海水动力发生较大变化,上游河流携带的泥沙和生物碎屑逐渐沉积,以及西面径流量大的北仑河口的径流携沙在涨潮时经湾口直接运至珍珠港内,在研究区形成沉积,导致海底地形逐渐抬升,为附近漂来的红树林繁殖体定居、生长创造了良好条件,红树林形成后,又加速了泥沙沉积,使其不断向海扩展。Reclamation is one of the main drivers of mangrove forest loss, but in some area without mangrove forest, mangrove forest emerged after the seawall had been constructed, and few researches had focused on the mechanism for their establishment and expanding. In this paper, Tahji-Wanwei seawall which was con- structed in the open sea in the Pear bay in Fangchenggang, Guangxi, China was took as the study site. We had analyzed the establishment and spatial dynamic of mangrove forest since the seawall had been constructed in April 1969 with temporally high resolution remote sensing images （in 1960, 1989, 2001, 2010, 2013 and 2015） and field investigation in August 2016. The results indicated that mangroves （Aegiceras corniculatum community） were formed in 1981, 12 years after the completion of the seawall construction, they expanded in- to a zonal patch with a length of 640 m and average width 25 m （patch l） till the year of 1989, three new patches were found during the period of 1989 to 2001, they were ascertained to be established in 1989, 1993 and 1995 respectively, and two other new patches were established from 2013 to 2015, one was established in 2011 and another in 2013. The area of mangrove forest increased from 1.62 ha in 1989 to 19.71 ha in 2015, for it increased rapidly in the early stages, but since 2007, the average annual increase rate decreased gradual- ly. It also revealed the landward border of patch 1 keep stable and the annual progradation of seaward border changed from 1.4 m to 6.0 m during the period of 1989 to 2015, with the trend of expanding slowly in the ear- ly stage and quickly in the late stage. The expanding was the major component of spatial change of mangrove patches, accompanied by shrunken and fragmentation in somewhere. The mechanism of the establishment and development of mangrove patches was that the pear bay become a funnel-shaped bay after the seawall had been built and the hydrodynamic changed dramatically, in turn, most sediment and organic filings which were carried

关 键 词：红树林 海堤 沉积 斑块 机制 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置] P966[自动化与计算机技术—控制科学与工程]