Effects of fencing and grazing management on bud bank in a semiarid steppe on the Loess Plateau

In perennial grassland ecosystems, the bud bank plays an important role in vegetation maintenance and recruitment. In this study, we used field root-digging to examine the bud bank, analyze above-ground vegetation characteristics, and below-ground bud bank density, under fencing and grazing management measures. Results showed that the bud bank in a semiarid perennial steppe on the Loess Plateau was dominated by tiller buds, and bud bank density ranged from 832 to 6 848 bud·m-2. Short-term fencing significantly increased the bud bank density and the density of grass bud banks, and decreased the density of forb bud banks in relation to grazed grasslands (P<0.05). The change of tiller buds, rhizomatous buds and root sucker buds caused a change in total bud bank density under two management types. The density of tiller buds and rhizomatous buds was significantly higher and the density of root sucker buds was significantly lower in grasslands fenced for five years than in grazed grasslands (P<0.05). Grass bud bank density was significantly and positively correlated with above-ground biomass, but negatively correlated with above-ground shoot numbers (P<0.05). To a certain extent, the effects of grazing and fencing on aboveground vegetation in a semiarid steppe on the Loess Plateau are mediated through grass bud bank demography. The bud bank is an excellent predictor of the above-ground vegetation. We can predict grassland productivity and succession direction using bud bank determination.