海平面上升通过增加洪水风险威胁沿海安全。沿海沙丘提供了自然形式的沿海保护。了解限制沙丘早期发展的驱动因素对于评估沙丘发展是否可以与海平面上升保持同步是必要的。在这项研究中,我们探索了沙丘建筑植物物种在多大程度上限制了它们在荷兰沙质海岸的空间分布。我们进行了野外移植实验和温室实验,其中有两个沙丘建草Ammmophilaarenaria和Elytrigiajuncea。在田野里,我们测量了四个植被区的盐度并监测了移植草的生长:(I)无植被的海滩,(II)E.juncea发生,(三)两种物种共存,和(IV)A.arenaria占主导地位。在温室里,我们对这两个物种进行了六种土壤盐分处理,有和没有盐雾。我们监测了生物量,光合作用,叶钠,和生长季节的营养浓度。植被区与夏季土壤盐分的相关性较弱;I区和II区的盐分明显高于III区和IV区。Ammophilaarenaria表现相同(II区)或更好(III区,IV)比大肠杆菌,表明土壤盐分并不限制物种表现。这两个物种都表现出严重的冬季死亡率。在温室里,A.arenaria生物量随土壤盐分线性下降,可能是渗透胁迫的结果。Elytrigiajuncea对土壤盐分显示出非线性响应,最佳盐分为0.75%。我们的发现表明,土壤盐分胁迫要么发生在冬季,或者植被沙丘的发育对土壤盐分的敏感性比迄今预期的要低。
Rising sea levels threaten coastal safety by increasing the risk of flooding. Coastal dunes provide a natural form of coastal protection. Understanding drivers that constrain early development of dunes is necessary to assess whether dune development may keep pace with sea-level rise. In this study, we explored to what extent salt stress experienced by dune building plant species constrains their spatial distribution at the Dutch sandy coast. We conducted a field transplantation experiment and a glasshouse experiment with two dune building grasses Ammophila arenaria and Elytrigia juncea. In the field, we measured salinity and monitored growth of transplanted grasses in four vegetation zones: (I) nonvegetated beach, (II) E. juncea occurring, (III) both species co-occurring, and (IV) A. arenaria dominant. In the glasshouse, we subjected the two species to six soil salinity treatments, with and without salt spray. We monitored biomass, photosynthesis, leaf sodium, and nutrient concentrations over a growing season. The vegetation zones were weakly associated with summer soil salinity; zone I and II were significantly more saline than zones III and IV. Ammophila arenaria performed equally (zone II) or better (zones III, IV) than E. juncea, suggesting soil salinity did not limit species performance. Both species showed severe winter mortality. In the glasshouse, A. arenaria biomass decreased linearly with soil salinity, presumably as a result of osmotic stress. Elytrigia juncea showed a nonlinear response to soil salinity with an optimum at 0.75% soil salinity. Our findings suggest that soil salinity stress either takes place in winter, or that development of vegetated dunes is less sensitive to soil salinity than hitherto expected.