黄河三角洲新生湿地土地覆被演替图谱

本文根据黄河三角洲新生湿地盐生、湿生、中生以及人工等不同生境的生态景观类型 ,将本区土地覆被类型分为 9类 ,即研究区海域、滩涂、柽柳 -翅碱蓬群落、獐毛 +白茅群落、芦苇 +荻群落、有林地、天然河流与人工水体、耕地和居民工矿用地。从遥感影像数据 (包括LandsatTM432、CBERS 1CCD432 )和专题矢量数据中提取了 1 984、 1 991、 1 996和 2 0 0 0年四期土地覆被数据 ,采用区域质心函数计算四个时期 9类覆被的分布重心 ,并合成土地覆被重心演替过程图谱 ,通过图谱分析 ,归纳出湿地植被演替的三种模式 ,即陆进模式、海退模式以及人类活动影响模式 ,为认识新生湿地植被演替规律以及人类活动的影响、制定湿地保护措施提供参考依据。

Tupu analysis on the land cover evolving patterns in the new-born wetland of the Yellow River Delta

The new-born wetland in the Yellow River Delta (YRD) is located in the active river mouth in the east of the YRD, which is one of the separate parts of the Nature Reserve in YRD. From 1976 to 2000, as Yellow River water with high sediment content flowed over the flood plains, a progressing coastline and conspicuously changing land cover in this new-born wetland have occurred. Spatial and temporal landscape patterns resulting from interactions between natural conditions (e.g. vegetation, soil properties, and hydrology) and anthropogenic land use activities (e.g. agriculture, road construction and oil exploration) changed greatly during the last 20 years. Landscape is classified into 9 zones according to its different land covers in this region, i.e., sea in the study Bohai area, tidal flat, Seablite-Chinese tamarisk, Chinese aeluropus-Lalang grass, Common weed, Hankon willow and artificial forest, water bodies, agriculture area, and residence, road and oil field zone. They respectively stand for saline habitat, swamp habitat, neutral habitat and artificial habitat for different ecosystems. The archive of satellite data allows us to quantify land cover changes in the region over the past 20 years. Based on supervised classification by ERDAS with field survey and statistical data, fourtemporal land cover classifications were achieved by LandsatTM432,CBERS-1 CCD432 imager and vector data from atlas of the Yellow River Delta covering 1984, 1991, 1996 and 2000. Two ecological evolving series are concluded in those maps and intertwined with each other in the region, i.e., the wetland ecological evolvement and the saline ecological evolvement. Three evolving patterns of the zonal centroid of these 9 types of landscapes are summarized according to their different spatial distributions and temporal evolvement directions. One is the Land-evolving pattern, which is followed by tidal flats, common weed, water bodies, forested land, and Seablite. Another one is the Sea-backward pattern, which is followed by sea in the study area and Chinese aeluropus-Lalang grass. The third pattern is Human-resulting pattern, i.e., cultivated land and residence and industrial zone, which is mostly controlled by human beings in suitable living environment for productivities.