Ma Miaojun, Ma Zhen, Du Guozhen
State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, P.R China.
PLoS One. 2014 Jul 1;9(7):e101458. doi: 10.1371/journal.pone.0101458. eCollection 2014.
Although 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.
We 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.
Species 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/SIGNIFICANCE: Water 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.
尽管在许多生态系统中已记录了水位对土壤种子库中种子萌发的影响，但其机制尚未完全了解，并且迄今为止尚无关于该主题的实证研究。此外，对于青藏高原高寒地区干旱和盐碱化湿地种子库水位的影响尚未开展任何研究。
我们研究了水位（0厘米、5厘米和10厘米）对典型、干旱和盐碱化湿地0至5厘米和5至10厘米深度土壤种子库中种子萌发和幼苗建立的影响。我们还探讨了土壤种子库在干旱和盐碱化湿地恢复中的潜在作用。
物种丰富度随水位升高而降低，但种子密度几乎没有变化。在所有三个湿地中，不同水位的种子库物种组成存在巨大差异，尤其是在0厘米与5厘米以及0厘米与10厘米之间。干旱湿地0厘米水位下种子库与植物群落之间的物种组成相似度高于其他两个湿地。在所有三个湿地中，0厘米水位下的相似度远高于5厘米和10厘米水位。高寒湿地植物群落的物种组成在干燥和盐碱化后发生了显著变化，然而，无论环境如何变化，种子库的物种组成都没有改变。
结论/意义：水位极大地影响种子库补充和植物群落建立。此外，恢复栖息地中的不同水位可能决定其植物群落的物种组成。种子库在退化湿地的恢复中很重要。干旱和盐碱化湿地的成功恢复可能取决于种子库。
