大规模排水前后若尔盖高原湿地景观格局特征变化

Changes in landscape patterns of alpine wetlands on Roige plateau before and after drainage

基于Apack软件应用景观格局分析的方法定量研究了排水前后若尔盖高原高寒湿地景观空间分布格局特征。结果表明,若尔盖高原湿地在大规模排水前湿地面积占总景观面积的11.07%,排水后缩减为8.9%,由于湿地景观与非湿地景观之间发生大面积的转移;大规模排水前若尔盖高原湿地景观面积排水前后湿地景观结构均以自然湿地景观为特征,其中,沼泽湿地景观在自然湿地景观中占绝对优势,占湿地景观总面积的95%以上;若尔盖高原湿地景观空间格局特征均以若尔盖县的湿地景观面积最大,红原县和玛曲县居中,阿坝县和碌曲县最小;各县湿地景观类型构成比例均以沼泽湿地景观为主所占比例最大,基本保持在90%以上的水平,其他湿地景观类型的构成比例较小。与排水前相比,各类型自然湿地景观的斑块数都明显减少,平均斑块面积增加,最大斑块面积除河流湿地外也表现为增加变化;湿地景观多样性指数、均匀度、优势度和分维数均表现为下降变化。

Spatial distribution patterns characteristics of alpine wetland landscapes on Roige plateau before and after drainage in a large scale was studied using landscape pattern analysis methods based on Apack software.Results showed that the total area of wetland before drainage took up 11.07%of the regional area,but they reduced to 8.9%because most wetland landscapes was modified into nonwetland landscapes after drainage.Wetland landscape structure was characteristic of natural wetland landscape before and after drainage,in which marsh wetland landscape was the dominated wetland type,taking account on more than 95%of the total wetland landscape area.As far as wetland landscape area concerned,Roige county had the largest area of five counties,followed by Hongyuan county and Maqu county,and then Aba county and Luqu county;about 90%of wetland landscape consisted of marsh wetland in each county.Compared with the wetland landscape pattern before drainage,patch numbers of all types of natural wetlands all decreased,but the average patch area showed a increase,and the largest patch area also increased with the exception of river wetland landscape;in the landscape levels,these wetland landscape pattern indices such as shannon-weaver index, domination index,event index and fractal dimentation index all showed a decrease after drainage.