Abstract: Effects of nitrogen (N), phosphorus (P) and potassium (K) fertilizations on plant community coverage, plant diversity and economic herbage groups in a degraded alpine steppe on the northern shore of Qinghai Lake was examined during 2011-2013 in the present study. The threeyear results showed that the total plant community coverage of fertilized treatments in the second (2012) and third year (2013) was significantly higher than that in the first year (2011). Meanwhile, plant community coverage also increased as the fertilization continued, but different fertilization treatments showed distinct responses in comparison with no fertilization treatment. All fertilization treatments reduced the species richness of community, and the species richness decreased as the fertilization continued. However, there was no consistent pattern in the change of Simpson index, Shannon index and Pielou evenness index after fertilization. Different economic groups responded distinctly to fertilization. The aboveground biomass of grass and forb species increased significantly (P<0.05) in the second and third years after fertilization, while that of sedge and legume species had no obvious change after fertilization.

Key words: distribution pattern, resource restoration, species composition, fish eggs, fish larvae, artificial reefs