西江中游典型河段岸线带景观格局分析

Landscape Pattern Analysis of the Riparian Zone in the Middle Reaches of the Xijiang River

西江中游浔江河段及岸线带分布有多处重要的国家级自然保护区及水功能区,为探讨该区域近年景观格局变化对自然生态环境的影响,基于Landsat 7和Landsat 8卫星遥感影像对该区域景观特征值的近年演变特征进行了计算分析。结果显示,研究区域仍维持农田基底不变,农田基底占比略有下降,林业用地占比下降2.8%,建设用地和裸地有所增加,水域面积占比基本不变;农田和建设用地最大斑块指数LPI提升明显,水体LPI较高,其他斑块LPI基本维持不变;人工斑块(建设用地、农田、沙石裸地)和水体边缘密度值(ED)都有不同程度升高,自然林地边缘密度(ED)值有所下降,景观蔓延度指数(CONTAG)下降,破碎化程度较高;Shannon景观多样性指标(SHDI)较小,景观多样性低。总体显示该区域农田耕种效率和城镇化显著提升,景观破碎化程度提升,生境质量下降,不利于自然生物的迁徙以及种群扩散和迁入,导致自然生态系统活力下降。

There are several important national nature reserves and water function protection zones in the river and riparian of the middle Xijiang River.In order to explore the impact of landscape pattern changes on the natural ecological environment.Based on Landsat 7 and Landsat 8 satellite images,this paper calculates and analyzes the evolution characteristics of the regional characteristic values in recent years.The results show that the farmland base remains unchanged in the area,the proportion of farmland base has decreased slightly,the proportion of forestry land has decreased by 2.8%,the construction land and bare land have increased,and the proportion of water area has remained basically unchanged;the farmland and construction land's LPI has improved significantly,the water body has a higher LPI,and the other plaque LPIs have remained basically the same;artificial plaques(construction land,farmland,bare sandy land)and water edge density values(ED)have increased to varying degrees.The natural forest land edge density values(ED)have decreased,the landscape spread index(CONTAG)decreased,and the degree of fragmentation is higher;Shannon's landscape diversity index(SHDI)is small,and landscape diversity is low.Overall,it shows that the farmland cultivation efficiency and urbanization in this area have significantly improved,the degree of landscape fragmentation has increased,the quality of habitats has decreased,which is not conducive to the migration of natural organisms and the spread and migration of populations,leading to a decline in the vitality of natural ecosystems.