Effects of continuous slope gradient on the dominance characteristics of plant functional groups and plant diversity in alpine meadows

Abstract

Many studies reported the effect on plant functional groups and plant diversity under discontinuous slope gradient. However, studies on the effect of continuous slope gradient on plant functional groups and plant diversity in alpine meadows have rarely been conducted. We studied the effect of a continuous slope gradient on the dominance characteristics of plant functional groups and plant diversity of alpine meadows on the Tibetan plateau-in Hezuo area of Gannan Tibetan Autonomous Prefecture. Altogether, 84 samples of alpine meadows grass and 84 soil samples from seven slope gradients at sunlit slopes were collected. By using analysis of variance (ANOVA) and Pearson correlation coefficient, this study revealed: (1) Continuous slope gradient is an important factor affecting plant communities in alpine meadows, due to the physical and chemical characteristics of the soil and water content. The number of families, genera, and species increased first then decreased at the different slope gradient levels, respectively; (2) there is a close relationship between the soil and plant functional groups, and plant diversity. In other words, the slope determines the functional groups of plants and the soil nutrients; and (3) soil characteristics (pH value, Soil Total Nitrogen, SoilWater Content) are the determining factors of the plant community characteristics at each slope gradient level. To conclude, a continuous slope gradient is an important factor that affects plant communities in alpine meadows.