Effect of elevation changes on bud bank characteristics of alpine meadow
on the Zoige Plateau
Abstract
Overgrazing and low temperature prevent plants sexual reproduction, and
belowground bud banks play an important role in perennial plant
communities. The purpose of the study is to explore the bud bank
characteristics of alpine meadow with elevation changes. We studied the
bud bank distribution, size and composition of alpine meadow at 3450 to
3950 m elevation using a unit soil excavation method on the eastern
Zoige Plateau. Our results showed that the bud density at the low
elevation was higher than that at the high elevation as a whole. The bud
bank comprise tiller, long and short rhizome buds. Bud bank composition
varied with elevation, tiller buds were the dominant ones, accounted for
35.47% to 65.28% of total buds. The tiller bud density was significant
correlated with the elevation, and the proportion of tiller bud and
short rhizome bud significant correlated with the elevation. Buds were
mostly concentrated in 0-10 cm sod layer, accounted for 93.41% to 100%
of total buds, and there were fewer buds distributed in 10-30 cm sod
layer. The aboveground biomass of plants increased gradually with
increasing elevation, and the belowground biomass decreased gradually as
a whole. The aboveground biomass was extremely significant correlated
with the tiller buds density. Redundancy analysis (RDA) showed that sod
layer properties affected bud bank composition. Total phosphorus, total
nitrogen, available phosphorus content was the most important factor
explaining and contributing to the variation of bud density. Studies
have shown that plants in alpine meadows maintain a certain size of bud
banks, which ensures the renewal and recovery of the plant community in
the later stages. The distribution and composition of plant bud banks
vary with increasing elevation, plants constantly alter the bud bank and
adjust propagation strategy to cope with environmental changes and
maintain the community stability.