高寒草地“石漠化”分级初探

A Preliminary Study on the Classification of“Rocky Desertification”in Alpine Grassland

高寒草地“石漠化”是指植被、土壤覆盖的草地转变为岩石裸露和砾石覆盖、土壤严重侵蚀、草地生产力下降的一种草地退化过程,其对青藏高原地区的生态安全造成威胁。文章在滇西北喀斯特石漠化分类和程度分级研究的基础上,结合青藏高原“石漠化”现状与景观特征实地调查,选取基岩裸露、植被覆盖、小生境组合、砾石含量、土层厚度和坡度6个因子为指标,通过聚类分析划分草地石漠化类型,将高寒草地“石漠化”划分为草地喀斯特和草地砾石化,通过构建石漠化程度指数模型RDI(Rocky desertification index),初步提出青藏高原高寒草地“石漠化”等级划分标准和图斑基本特征。

The“rocky desertification”of alpine grasslands refers to the process of grassland degradation in which vegetation and soil cover are transformed into bare rocks and gravel cover,soil erosion is severe,and grassland productivity decreases.It poses a threat to the ecological security of the Qinghai Tibet Plateau region.Based on the research on the classification and degree grading of karst rocky desertification in northwest Yunnan,combined with the current situation of field investigation and landscape characteristics of rocky desertification in the Qinghai Tibet Plateau,this article selects six factors as indicators:bedrock exposure,vegetation coverage,niche combination,gravel content,soil layer thickness,and slope.Through cluster analysis,rocky desertification is divided into grassland karst and grassland gravel petrification,by constructing the Rocky Desert Index(RDI)model for the degree of rocky desertification in the Qinghai Tibet Plateau,a grading standard and map pattern for“grassland rocky desertification”are proposed.