近20年来珠江三角洲滨海湿地景观的变化特征

Variations of Coastal Wetland Landscapes in the Pearl River Delta in the Last 20 Years

用4景1986—2005年的Landsat TM卫星遥感影像作为数据源,结合野外调查,研究20 a来珠江口滨海湿地的类型与景观变化情况。结果显示,珠江口地区受人类活动影响剧烈;湿地面积占据滨海地区面积不足一半,而湿地中,绝大部分又为人工湿地。从1986年起,湿地类型变化显著,人工建设用地的面积大大增加,湿地面积在2000年前缓慢增加,2000年后出现下降趋势。湿地景观指数变化相对较小,多样性、均匀度、分形维数略呈下降趋势,优势度和内部生境破碎化指数略呈上升趋势,廊道密度指数下降较显著。珠江口滨海湿地出现了一定程度的退化,尤其是2000年后湿地退化有加快趋势,对滨海湿地,特别是天然湿地的保护和重建工作需要加强。

Wetland types and landscape variations in the Pearl River Delta（PRD） during the last 20 years（from 1986 to 2005） were studied based on 4 Landsat TM satelite remote sensing images.The results show that the Pearl River estuary has been influenced intensively by the human activities,and the wetland area can only make up less than half of the whole coastal area.Even within the wetlands,the most are the artificial wetlands.Since 1986,the types of wetlands have changed distinctly.The land area used for the human constructions increases greatly,whereas the wetland area increased slowly before 2000 and decreased after 2000.The change in the wetland lanscape index is relatively small and the diversity index,the evenness index and the fractal dimension index tend to decrease slightly.The richness index and the habitat fragmentation index also increase slightly.However,the gallery density index decreases notably.A degradation of the coastal wetlands occurrs,to some extent,in the Pearl River estuary.Particuarly after 2000,the degradation of the coastal wetlands tended to intensify.Therefore,the pretection and restoration to the coastal wetlands,especially to the natural wetlands,should be enhanced.