黄河中游连伯滩湿地景观格局变化

以黄河中游连伯滩湿地1990、1995、2000、2005年4个时相的卫星遥感影像为基础,通过斑块密度、斑块边缘长度、景观多样性指数、优势度、景观破碎化指数、平均斑块分维数等景观空间格局指数,系统地分析了连伯滩湿地1990年以来湿地景观空间格局变化情况。研究结果发现:(1)1990-2005年,草地、耕地、林地斑块面积在增加,而水域和滩地斑块的面积在不断减小;(2) 湿地景观多样性指数从1990年的0.9947增加到2005年的1.1247,表明随着人类干扰活动的增加,景观结构异质性增大;(3) 斑块数量的增加、斑块密度的增加以及斑块边缘长度的增加等都说明该区域破碎化程度增加。造成湿地退化的自然因素主要是长期干旱导致黄河及汾河径流补给大大减少,而人口的压力则是湿地退化最根本的原因。

Wetland landscape transition pattern of Lianbo Beach along the Middle Yellow River

This study examined the data extracted from the multi-band satellite remote sensing images of Lianbo Beach during four phases of 1990, 1995, 2000 and 2005. The analysis employed a series of spatial landscape pattern indices such as patch density, length of patch edge, landscape diversity index, species dominance, landscape fragmentation index, and the mean fractal dimension index to systematically scrutinize the spatial alteration patterns of the wetland landscape at Lianbo Beach since 1990. The results include:(1) The changes in patch areas from 1990 to 2005 exhibit the increase in grassland, farmland and woodland but the decrease in water bodies and beaches;(2) The intensive anthropogenic activities correspond to the enlarged landscape heterogeneity as demonstrated by the increase of wetland landscape diversity index of 0.9947-1.1247 between 1990 and 2005;(3) The increase of patch numbers, patch density and the length of patch edge, all indicate the enhanced degree of fragmentation in this region. The major natural factor for wetland degradation at Lianbo Beach is the significant reduction of runoffs along the Fenhe River and the Yellow River due to long-lasting drought. Additionally the population pressure serves as the ultimate cause for wetland degradation.