In this research, the researchers investigated the effects of enhanced UV-B on the photosynthetic rate and Chl-a content of algal crusts of natural vegetation area, and that of having developed for 51 years and 26 years in artificial vegetation areas in the southeast of the Tengger Desert. The results indicated that: (1) the enhanced UV-B significantly inhibited the Chl-a content (P<0.05) of algal crusts in the 51 years and 26 years artificial vegetation areas (P<0.05), and the Chl-a content of algal crusts treated by enhanced UV-B had no significant difference among these three vegetation areas (P>0.05); (2) the photosynthesis of algal crusts at the three successional areas decreased profoundly after treatment by enhanced UV-B (P<0.05), and the photosynthetic rate of algal crusts in the natural vegetation area, 51 years and 26 years vegetation areas were 1.8 μmol·m^-2·s^-1, 2.2 μmol·m^-2·s^-1 and 1.9 μmol·m^-2·s^-1 respectively, which decreased by 21%~49%, 12%~22% and 24%~59% compared with the control area. After treatment by enhanced UV-B, the photosynthetic rates of algal crusts had no difference among the three successional areas (P<0.05). The results indicated that the enhanced UV-B significantly inhibited Chl-a contents and photosynthetic rate of algal crusts, and this will impose effects on ecosystem productivity of algal crusts.

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