基于航空高光谱影像的青海省玛多县高寒草原景观格局特征分析

摘要

Landscape ecology has been widely used in grassland resource management and in ecological security evaluation.A multi-scale analysis of landscape statistics is very important for correlation with ecological processes.Acquiring features of landscape patterns from different grassland types with various fractional vegetation cover is one type of basic work in landscape scale analysis of grassland degradation.Extraction of small-scale landscape patterns from high resolution remote sensing is a useful attempt to carry out landscape-scale analysis.The present study analyzed different spectral characteristics of different grassland types and took precision grassland types mapping based on airborne high spatial resolution hyperspectral PIS imagery in Maduo county,Qinghai province.Metre-resolution landscape pattern differences in alpine steppe study areas with different fractional vegetation cover were explored through three landscape indices (landscape heterogeneity,landscape fragmentation and landscape dominance level).The results showed that landscape heterogeneity index and landscape dominance index are closely related to the level of fractional vegetation cover in alpine grassland.However,with reduced fractional vegetation cover of alpine steppe sample areas,fragmentation index initially decreased but then increased.%景观生态学在草地资源管理、生态安全评价方面已得到广泛应用,开展不同尺度的景观格局特征分析对景观生态过程研究十分重要.获取不同覆盖度草地的景观格局特征是青藏高原草地退化等生态系统演变研究的基础工作之一.从高分辨率遥感的角度提取中小尺度上草地景观格局特征,是开展景观格局尺度分析的有益尝试.本研究通过高空间分辨率的PIS航空高光谱影像,分析不同草地类型的光谱特征差异,开展玛多实验区草地类型精细分类,并从景观异质性、景观优势度和景观破碎度3个景观层次,分析米级分辨率下不同覆盖度高寒草原样地的景观格局特征差异,发现高寒草原样地的景观优势度、景观异质性与草地覆盖度分别呈正、负相关,而破碎度指标则随着高寒草原草地覆盖度的降低出现先升高后降低的现象.