Response of underground bud bank to degradation in a alpine meadows on
the Qinghai-Tibet Plateau
Abstract
Exploring the diversity and formation mechanism of under-ground bud
banks is essential for understanding population regeneration and
community succession. However, there are few studies on the response of
bud bank size and composition to different degradation gradients in
alpine meadows. In view of this, we investigated the size and
composition of bud bank under four degradation gradients
(non-degraded:ND, lightly degraded:LD, moderately degraded:MD, and
heavily degraded:HD) on a typical alpine meadow in Tibet, China, and
analyzed the influence of soil physical and chemical properties on the
correlation of bud bank types. Our results show that in ND meadows,
rhizome buds dominate, in LD meadows, tiller buds account for a larger
proportion, and in MD meadows, root-sprouting buds dominate. The total
bud bank density decreases as the degradation gradient increases. The
density of cyperaceae buds decreased with the degree of degradation. The
density of leguminosae was insignificant in each degradation gradient.
The density of gramineae and weeds were dominant in LD and MD meadows,
respectively. Rhizome bud density was significantly positively
correlated with soil organic carbon (SOC), total nitrogen (TN), NH+ 4-
N, and NO- 3 - N (P < 0.001 for all), soil water content
(SWC), total phosphorus (TP) and available phosphorus (AP) (P
< 0.01), and negatively correlated with pH (P <
0.001). Tiller bud was significantly positively correlated with SWC and
TP(P < 0.05). Root-sprouting buds are only significantly
negatively correlated with TP(P < 0.05). Therefore, our
research shows that rhizome buds are more important in ND meadow
habitats, tiller buds are more important in LD meadow habitats, and
root-sprouting buds are more important in MD meadows. In addition,
rhizome buds have been proved to be suitable for survival in a weak acid
environment.