祁连山中段高寒草甸草毡表层发育程度的空间分异及环境影响因子

高寒草甸植被下的草毡表层能够发挥水土保持、水源涵养等生态环境效益,是高寒草甸植被生态功能发挥的核心,认识草毡表层发育程度的空间分异及环境影响因子有利于深入理解高寒草甸在高原生态系统中的作用。本研究以祁连山中段高寒草甸分布区为研究区,依据根系体积并结合草毡层厚度以及土壤容重,将草毡表层划分为弱发育、中等发育以及强发育草毡。分析了不同发育程度草毡的地形、植被、气候等环境特征,并采用支持向量机模型对其分布进行了空间制图。结果表明:祁连山中段发育程度较高的草毡表层趋向于分布在水分条件较好的低海拔、缓坡,低坡位以及北向坡的位置,以嵩草属植物为主,中等以上发育程度的草毡地表植被及水分条件都较好;发育程度较高的草毡表层年均温较高,各发育程度草毡表层降水量差异不显著。空间分布结果整体与现有的高寒草甸植被类型分布具有高度的一致性,但空间分辨率更为详细,并且实现了不同发育程度草毡表层的空间细分。

Spatial distribution and environmental factors affecting mattic epipedon at different developmental levels in alpine meadows in the middle of Qilian Mountains

Mattic epipedon, which has important ecological benefits such as water retention and soil conservation, plays a pivotal role in the ecological function of alpine meadows. Therefore, exploring the relationships between the mattic epipedon and environmental factors, as well as spatial distribution of the mattic epipedon at different developmental levels are essential to elucidating the role of alpine meadows in the plateau ecosystem. In this study, samples of mattic epipedon were collected in alpine meadows in the middle of Qilian Mountains and were classified into three developmental levels primarily based on root volume, followed by thickness and bulk density. The relationships between mattic epipedon and environmental factors, such as topography, vegetation, and climate, were analyzed. The support vector machine model was used to map the spatial distribution of the mattic epipedon. The results showed that areas with relatively low elevation, gentle slope, low slope position, and a north-facing aspect, which were highly related to high soil moisture content, had a higher occurrence probability of mattic epipedon at high developmental levels. Vegetation covering the mattic epipedon at higher levels was usually well-developed and composed primarily by Kobresia and other hygrophilous plants. A well-developed mattic epipedon existed where there was significantly higher mean annual temperature, whereas there were no significant differences in mean annual precipitation regarding the existence of mattic epipedon at different developmental levels. The distribution of the mattic epipedon was highly consistent with the distribution area of alpine meadows, although at a higher spatial resolution. Furthermore, this study presented the spatial distribution of mattic epipedon at different developmental levels.