围填海背景下唐山市滨海湿地景观格局演变研究

Landscape Pattern Evolution of CoastalWetlands in Tangshan City under the Background of Reclamation

20世纪90年代以来,大规模的围填海活动导致唐山市滨海湿地景观格局发生了演变。以唐山市南部的乐亭县、曹妃甸区和丰南区所辖范围为研究区,采用面向对象分类方法,利用1990年、2000年、2010年和2020年的Landsat TM/OLI影像数据,提取出唐山市滨海湿地的土地利用信息,分析了4个时期唐山市滨海湿地景观格局的时空变化。研究结果显示,1990年、2000年、2010年和2020年,研究区的滨海湿地(包括水域、沼泽、盐田、养殖池和滩涂)面积分别为1496.25 km^(2)、1549.50 km^(2)、1208.97 km^(2)和1178.12 km^(2),与1990年相比,2020年,研究区的滨海湿地面积减少了21.26%,其中,77.12%的滨海湿地被围填为人工表面;受围填海活动影响,4个时期研究区的各类型滨海湿地的质心位置持续移动,其中沼泽和滩涂质心位置变化较为明显;4个时期研究区盐田的破碎化程度低,滩涂的连通性好,2000年沼泽和水域的破碎化程度较高,养殖池在唐山市滨海湿地景观格局中占有绝对优势;围填海等人类活动是导致唐山市滨海湿地景观格局变化的主要驱动因素。

Since 1990s,extensive reclamation activities have led to the evolution of the landscape pattern of the coastal wetlands in Tangshan city.Using Landsat images in 1990,2000,2010 and 2020,the land use information of the coastal wetlands in Tangshan city was extracted by an object-oriented classification method in this paper.The spatiotemporal analysis of the landscape pattern characteristics of the coastal wetlands under reclamation activities was conducted.The results showed that the area of the coastal wetlands has decreased by 21.26%from 1990 to 2020,in which 77.12%of these coastal wetlands being reclaimed for artificial surfaces.Affected by reclamation activities,the centroids of various types of coastal wetlands in 4 periods continued to shift,with the centroids of marshes and tidal flats exhibiting more pronounced changes.In 4 periods,the salt fields in study area exhibited a low level of fragmentation,with the tidal flats having the best connectivity.The marshes and water bodies had the highest degree of fragmentation in 2000.The mariculture ponds held an absolute advantage in the landscape pattern of the coastal wetlands in Tangshan city.Human activities such as reclamation were the main driving factors behind the changes in the landscape pattern of the coastal wetlands in Tangshan city.