青藏高原高寒草地土壤水分生态特征研究现状

Research Progress in the Ecological Characteristics of Soil Water in Alpine Grasslands on the Qinghai-Tibetan Plateau

从土壤水分时空异质性、植被覆盖变化对土壤水分的影响、冻土变化对土壤水分的影响、人为活动对土壤水分的影响方面研究了青藏高原高寒草地土壤水分生态特征。在该领域研究中,前人已开始在小尺度采用植物进化学的角度解释青藏高原植被覆盖变化对水分再分配的作用,但是大尺度的研究不足;初步阐明了冻土季节性冻融的生态水文效应,但还缺少其与气候和地质相关的综合性分析;反映出青藏高原全球第三极土壤水分的地理分布的特殊性,但各个区域之间土壤水分特征差异的重要影响因素尚未明确。综上,今后应综合植被类型、冻土环境、地质、气候条件以及人为活动影响,多层次多尺度研究土壤水分变化的过程,从而为研究不同尺度土壤水分变化差异性和格局演变提供科学依据。

Soil water is an important factor constraining vegetation growth and spatial distribution of the alpine grasslands on the Qinghai-Tibetan plateau. Consequently, it affects the stability of local ecosystems. In this work, the ecological characteristics of soil water in the alpine grasslands on the Qinghai-Tibetan plateau were studied in four aspects, the spatial-temporal heterogeneity of soil water in the alpine grasslands, the impact of vegetation cover change on soil water in the alpine grasslands, the impact of per- mafrost change on soil water, and the impact of human activities on soil water in the alpine grasslands. The physiological basis of the impact of vegetation cover change on soil water reallocation from the perspective of plant evolution at local scale was explained in previous studies in this field, but studies in largescale are still insufficient; the eco-hydrological effect of seasonal freezing and thawing was clarified, but the comprehensive analysis of its related to climate and geology is lacking; and showed the specialty of the geographic distribution of soil water in the third pole of the world （i. e. , the Qinghai-Tibetan plateau）, but the significant influence factor of Soil water characteristic differences between regions is not yet clear. Future work should synthesize multisource and multi-scale information on soil water change impacted by vegetation cover, permafrost, geology, climate, and human activities to provide scientific bases for exploring the difference in soil water change at different scales and the ecological effect of pattern dynamics.