Effects of water level on three wetlands soil seed banks on the Tibetan Plateau.

Miaojun Ma,Zhen Ma,Guozhen Du,Shuang-Quan Huang

doi:10.1371/journal.pone.0101458

Abstract

BackgroundAlthough the effect of water level on germination in soil seed banks has been documented in many ecosystems, the mechanism is not fully understood, and to date no empirical studies on this subject exist. Further, no work has been done on the effect of water level on seed banks of drying and saline-alkaline wetlands in alpine areas on the Tibetan Plateau.MethodologyWe examined the effects of water level (0 cm, 5 cm and 10 cm) on seed germination and seedling establishment from soil seed banks at 0–5 cm and 5–10 cm depths in typical, drying, and saline-alkaline wetlands. We also explore the potential role of soil seed bank in restoration of drying and saline-alkaline wetlands.Principal FindingsSpecies richness decreased with increase in water level, but there almost no change in seed density. A huge difference exists in species composition of the seed bank among different water levels in all three wetlands, especially between 0 cm and 5 cm and 0 cm and 10 cm. Similarity of species composition between seed bank and plant community was higher in 0 cm water level in drying wetland than in the other two wetlands. The similarity was much higher in 0 cm water level than in 5 cm and 10 cm water levels in all three wetlands. Species composition of the alpine wetland plant community changed significantly after drying and salinization, however, species composition of the seed bank was unchanged regardless of the environment change.Conclusions/SignificanceWater level greatly affects seed bank recruitment and plant community establishment. Further, different water levels in restored habitats are likely to determine its species composition of the plant community. The seed bank is important in restoration of degraded wetlands. Successful restoration of drying and salinization wetlands could depend on the seed bank.

Highlights

Maqu wetlands have an important ecological function and a huge influence in the entire Yellow River basin [1,2]
[7] found that submerged species dominate the seed bank community when the sediments were flooded for most of the time, while terrestrial species dominated the seed bank community when the sediments underwent rapid drying. We found that both the terrestrial species and typical wetland species dominated the seed banks of three wetlands. [2] reported that there was no change in species composition of seed bank after alpine wetland drying and salinization
Species composition changed very little with alpine wetland plant community succession in the Tibetan Plateau [1]

Summary

Introduction

Maqu wetlands have an important ecological function and a huge influence in the entire Yellow River basin [1,2]. Despite the fact that the effect of water level on germination of soil seed banks is documented in many ecosystems [9,14], the mechanism is not fully understood, and to date no empirical studies on this subject exist in some sensitive habitats, especially in the alpine wetlands on the Tibetan Plateau. We concluded that the seed banks make a low contribution to regeneration of alpine wetland plant communities [1] but that seed banks have a high potential to contribution to restoration of saline–alkaline meadow in Tibetan Plateau [2].

Material and Methods

Results

Discussion