Abstract: As a main topographic factor in mountainous region, slope aspect is an indirect environmental factor inducing the differences of plant community species diversity and structure. Slope aspect can affect light intensity, soil temperature, soil moisture, and soil nutrients, and accordingly, produce important effects on the biodiversity, plant growth, productivity, and ecosystem functions. This paper studied the variation characteristics of plant community species diversity and their relationships with environmental factors on different slope aspects of an alpine meadow on QinghaiTibetan Plateau. In the habitat gradient from southfacing slope to northfacing slope, soil moisture content had a variation trend of northfacing slope > westfacing slope > southfacing slope, light intensity and soil temperature were in the sequence of southfacing slope > westfacing slope > northfacing slope, whereas soil nutrient contents were in the order of northfacing slope > westfacing slope > southfacing slope (except that the contents of soil total N and organic carbon were north-facing slope > south-facing slope > west-facing slope). The plant community species diversity in the habitat gradient was north-facing slope > westfacing slope > south-facing slope. Grasses were the main functional groups on south-facing slope, while forbs were the main ones on northfacing slope. Pearson’s correlation analysis showed that light, heat, water, and soil properties all affected the variations of species diversity along the habitat gradient from south-facing slope to north-facing slope, and soil moisture content was the key factor determining the variations of the plant community diversity.

Key words: Aromatic hydrocarbon degradation, Bioremediation, Adaptability, Species diversity