普者黑岩溶湖泊湿地湖滨带景观格局演变对水质的影响

湖滨带作为湖泊与陆地之间的过渡带,是健康湖泊生态系统的重要组成部分。湖滨带景观格局的演变会对湿地水质产生重要影响,因此探究影响岩溶湿地水质变化的湖滨带关键景观因子,对深入了解景观格局对岩溶湿地水质的影响过程与机制具有重要意义。选择普者黑岩溶湖泊湿地为研究对象,以2005、2007、2009、2011年共4年的Landsat遥感影像及水质监测数据为基础,通过划定湖泊湿地湖滨带缓冲区域,运用秩相关分析和冗余分析研究湖滨带景观格局对普者黑岩溶湖泊湿地水质的影响。结果表明,湖滨带不同缓冲区内景观结构类型比例差异较大;枯水期水质与土地利用类型和景观格局指数的影响大于丰水期;景观格局在不同缓冲区尺度对岩溶湿地的水质具有不同的效应;随着监测点缓冲距离的增加,个别景观指数可较好的揭示湖滨带景观格局演变对岩溶湿地水质的影响,其中,蔓延度指数(CONTAG)、斑块结合度指数(COHSION)、均匀度指数(SHEI)对水质参数的影响较大,边界密度(ED)、聚集度(AI)对水质参数的影响随缓冲距离的增加逐渐减弱,其他景观指数对水质影响差异并不明显,最大斑块指数(LPI)在缓冲距离≤300m的区域内与水质的关系较密切,面积加权平均斑块分维数(AWMPFD)与水质参数有显著负相关性,多样性指数(SHDI)对水质的影响具有不确定性;另外,大部分水质参数与土地利用面积比例有较好的相关性,且湿地面积比例是表征岩溶湖泊湿地水环境质量的主要指标。

The effects of landscape pattern evolution in Puzhehei karst lake wetland littoral zone on water quality

The lake littoral zone, an important transitional area between land and lake, is an integral part of a healthy lake ecosystem. The evolution of landscape patterns in the lake littoral zone will have an important effect on wetland water quality. Therefore, studying the key littoral zone landscape factors that affect karst wetland water quality changes is of great importance in understanding the process and the underlying mechanism regarding how landscape patterns effect karst wetland water quality. Using Puzhehei karst lake wetland as the study area, and obtaining Landsat remote sensing images and the collected water quality monitoring data from 2005, 2007, 2009, and 2011, we studied the influence of landscape pattern indices on Puzhehei karst lake wetland littoral zone water quality through delineating the buffer zones and using correlation and redundancy analysis. The results showed that the littoral zone landscape patterns were quite different in various buffer zones. The effects of water quality on land use type and landscape pattern indices in the low flow period was greater than that in the high flow period; the landscape patterns had different effects on the water quality of karst lake wetlands at different buffer zones. Individual landscape indices better revealed the influence of landscape pattern evolution on water quality in the Puzhehei karst lake wetland, accompanied by increased buffer zone distances. Among them, Contagion Index, Patch Cohesion Index, and Shannon''s Evenness Index values had a substantial influence on water quality, and Area-weighted Mean Patch Fractal Dimension exhibited a significantly negative correlation with water quality parameters. The effects of other landscape indices on water quality were not significant. Among them, the effects of Edge Density and Aggregation Index values on water quality gradually weakened accompanied by the increased buffer region distances. Largest Patch Index values were closely correlated with water quality when the buffer distance was less than 300m. Beyond this, the effect of Shannon''s Diversity Index on water quality was uncertain. Additionally, most water quality parameters showed a good correlation with land use type area, and the proportion of wetland area was the main index to characterize the water environment quality of the karst lake wetland.