Abstract: We explored the effect of three-year fencing on species diversity and functional diversity of plant communities of a meadow steppe in Saihanba, Hebei Province. The results showed that compared with grazing, fencing significantly altered soil chemical properties and plant community composition, with the dominant species changing from Plantago asiatica to Sanguisorba officinalis. Fencing did not change plant species diversity. In fenced plots, leaf and root functional richness were 16.9 (1.18 vs. 0.07) and 1460.2 (3.57 vs. <0.01) times as that in grazed plots, respectively; while leaf functional divergence and root functional evenness decreased by 7.7% (0.72 vs. 0.78) and 12.3% (0.57 vs. 0.65), respectively. In both fenced and grazed plots, species β-diversity was mainly contributed by turnover components (74.9% and 62.4%), while functional β-diversity was mainly contributed by nestedness components (Leaf: 82.6% and 70.6%; Root: 73.9% and 79.5%). In fenced plots, overall species and functional β-diversity were driven by the combination of soil properties and spatial factors (Species: R²=0.53; Leaf: R²=0.47; Root: R²=0.29). In grazed plots, overall species and functional β-diversity were mainly driven by spatial factors (Species: R²=0.31; Leaf: R²=0.36; Root: R²=0.40). In summary, there were differences in the effects of fencing on species diversity and functional diversity, and species turnover did not lead to trait turnover. Therefore, both species diversity and functional diversity should be considered when evaluating the effectiveness of grassland restoration. Exploring β-diversity and its components of communities in different dimensions helps us to better understand the mechanisms of community assembly.

Key words: meadow steppe, short-term fencing, β-diversity, species diversity, functional diversity