Abstract: Kingdonia uniflora is an endemic endangered clonal species in China and shows a patchy distribution pattern on small scales within its distribution area. In the present study, using Digital Photography Technology, Geographic Information System and Digital Plant Canopy Imager, we analyzed the dynamics of sunfleck, canopy structure, soil physical and chemical properties in forest within the K. uniflora distribution on the north slope of Mt. Taibai in China. The results showed that the number and area of sunfleck and the sunfleck index in sampling plots were significantly lower with than without K. uniflora. There were significant differences in canopy structure between the two types of plots. The transmission coefficients for diffuse penetration, the transmission coefficients for radiation penetration and the canopy gap area in the plots were smaller with than without K. uniflora, while the leaf area index was vice versa. In addition, there were no statistically significant differences in measured soil physical and chemical properties among the two kinds of plots. Therefore, we speculate that sunfleck is likely one of leading factors determining the distribution of K. uniflora on the north slope of Mt. Taibai.

Key words: moss crust, soil enzyme activity, soil nutrient, biological soil crust, Loess Plateau