近20年来河南沿黄湿地景观格局演化

Landscape Pattern Change of Regional Wetland along the Yellow River in Henan Province in the Last Two Decades

在遥感和GIS技术的支持下,结合河南沿黄湿地的区域特点,确定了河南沿黄湿地景观分类系统,通过采用景观多样性指数、优势度、景观破碎化指数、分布质心和扩展度等景观的空间格局指数,比较系统地分析了近20年河南沿黄湿地景观空间格局变化.结果表明:(1)河南沿黄湿地的分布面积呈显著下降趋势.1987～2002年湿地面积减少了19.18%,斑块数量增加了21.27%,斑块密度净增加0.5倍.斑块总边缘增加了129 0491 m,斑块平均边缘减少了117.84 m.(2)随着人类干扰强度增加,景观多样性下降,优势度增高.研究区景观多样性指数1987年为1.174,2002年降为0.9803,优势度指数由1987年的0.4355提高到2002年的0.6291.湿地的破碎化程度随着湿地面积的减小和斑块数量的增加,其破碎化程度越来越大,破碎化指数由1987年的0.0141增加到2002年的0.0172.(3)湿地景观要素中,稻田湿地面积在增加,而水库坑塘、河流、滩地、荒草沼泽地面积都在不断减少,其中荒草沼泽(芦苇沼泽)湿地面积减少幅度最大.1987年荒草沼泽湿地占整个湿地地区的0.5%,但到2002年只占0.11%.表明近20年来,人类活动对河南沿黄湿地景观格局变化的影响程度较大.

With remote sensing data and GIS, the classification system of wetland landscape of the region along the Yellow River in Henan Province is established. Using the indexes of the landscape pattern, such as landscape diversity index, landscape dominance index, landscape fragmentation index, distribution centroid and extended dimension, this article presents the dynamic change of wetland landscape pattern from 1987 to 2002. The results showed that: (1) The total area, the patch number and other index of wetland reduced obviously. The total area of wetland reduced 19.18%. The number of patches increased 21.17%, the patch density increased 50%, and the total perimeter length increased 1,290,491 m from 1987 to 2002. (2) Disturbed by human activity, landscape diversity index decreased from 1.1740 in 1987 to 0.9803 in 2002. While landscape dominance index increased from 0.4355 in 1987 to 0.6291 in 2002, and landscape fragmentation index increased from 0.0141 to 0.0172, which means that the shape of wetland was much irregular. (3) During the last nearly 20 years, the total area of the rice wetland increased, while the area of other types decreased. Among these wetland types, the area of the marsh wetland decreased most obviously. In 1987, it occupied 0.5% of the total area, but in 2002, it only occupied 0.11%.