七里海泻湖湿地演变过程及其生态环境效应分析

以河北省秦皇岛市昌黎县七里海泻湖湿地为研究区,选取1919～2005年间的4幅地形图和1987年以来的10景landsat TM(ETM)遥感影像为数据源,运用遥感和地理信息系统技术,研究了七里海泻湖湿地近百年的时空演变过程,分析了泻湖湿地演变的影响因素与生态环境效应.结果表明,近百年来,七里海泻湖面积发生明显变化,由1919年的711.1 hm2缩减为2005年的279.1 hm2;1919年泻湖周边沼泽湿地面积为2 263.3 hm2,2005年泻湖周边的沼泽湿地已经基本消失;1956年以前,泻湖湿地以自然演变为主,主要受雨量充沛、入湖河流径流量丰富的影响,泻湖水面面积呈逐年增加趋势,1956以后,受流域开发治理工程、围垦和水产养殖等人类活动的影响,泻湖及周边湿地水动力条件发生改变,泻湖周边天然湿地逐渐为人工湿地所代替,泻湖水面面积减小,淤积加重,湿地生态系统受到极大干扰,呈现出生物多样性降低、景观单一化、湿地效应减弱等生态环境恶化的特征.

The Evolution Process and Analysis on Eco-environmental Effect of the Qilihai Lagoon Wetland

The earthquake and tsunami that devastated coastal area in Nanggroe Aceh Darussalam Province and North Sumatra Province, especially Nias Island on December 26, 2004, caused damage to most mangrove and coastal forests in the areas. Before the 2004 tsunami, there is no report or publication about mangrove and coastal vegetation in Nias Island. The aims of this research were to describe the mangrove forests and coastal vegetation after tsunami disaster and to learn the ecological functions of mangrove forests and coastal vegetation on shore protection. Field surveys, in eastern, northern and western coast of Nias Island within 10 days of the middle weeks in March 2005 and in southern coast of Nias Island within 6 days of the first 2 weeks in November 2006 after the 2004 tsunami, were conducted. Our research results showed that dense mangrove forests and coastal vegetation had been proven to be effective on protecting coastal area from the tsunami, while heavy damage occurred in the areas that have degraded mangrove and coastal forests. Therefore, mangrove forests play an important role on shore protection, and this protection depends on the quality of the mangrove habitats. It should be noted that degraded habitats or habitats with mangrove associate species instead of true mangrove species do not provide adequate protection.