For many plants, regeneration from seed is vital for population recovery. Climate change is modifying the global hydrological cycle and a primary factor controlling germination of marine plants: salinity. How altered salinity regimes, and especially altered porewater salinity regimes, will regulate early life history stages of estuarine seagrasses is poorly understood. Here, we quantified the porewater salinity dynamics in two ephemeral estuaries that are dominated by the cosmopolitan genus Ruppia. Seedbank, germlings (germinated seeds) and seedlings were found in salinities ranging from 5 to 110 over an annual cycle. To understand the germination ecology of the dominant species, Ruppia polycarpa, seeds were exposed to treatments simulating current salinity regimes and those predicted under climate change. Seeds underwent a Dormancy treatment (15, 60, 150) followed by a Germination treatment (10, 20, 80). Generally, early life history stages were positively affected by hypersaline dormancy conditions if the subsequent Germination salinity was ≤ 20. Germination success was significantly higher for seeds transferred to 10 (65%) compared to 20 (49%) whilst no seeds germinated in 80 highlighting the risk of lower germination as estuaries become drier and more hypersaline with declining winter rainfall. However, germlings were found in situ in salinities ≥ 80 suggesting aspects of the salinity dynamics, not captured by our experimental conditions, may broaden tolerances. Dormant seeds were continuously present in situ and seedlings were observed throughout the whole of the growing season. These results are indicative of bet-hedging strategies. Future research should explore the capacity of these strategies to afford resilience to R. polycarpa to salinity variability under climate change.

对于许多植物来说，种子再生对于种群恢复至关重要。气候变化正在改变全球水文循环和控制海洋植物发芽的主要因素：盐度。盐度变化，尤其是孔隙水盐度变化，将如何调节河口海草的早期生命史阶段，人们知之甚少。在这里，我们量化了两个短暂的河口中的孔隙水盐度动态，这两个河口由世界性的Ruppia属控制。种子库、幼苗（发芽的种子）和幼苗在一个年度周期内的盐度范围为 5 至 110。了解优势种多壳斑蝶的萌发生态，种子暴露于模拟当前盐度状况和气候变化下预测的盐度状况的处理。种子经历休眠处理（15、60、150），然后进行萌发处理（10、20、80）。一般来说，如果随后的发芽盐度≤20，早期生命史阶段会受到高盐休眠条件的积极影响。转移到 10（65％）的种子发芽成功率显着高于 20（49％），而在 80 突出显示时没有种子发芽随着冬季降雨减少，河口变得更加干燥和高盐度，发芽率降低的风险。然而，在盐度 ≥ 80 的原位发现了幼苗，这表明我们的实验条件未捕获的盐度动力学方面可能会扩大公差。休眠种子持续存在于原地，并在整个生长季节观察到幼苗。这些结果表明了赌注对冲策略。未来的研究应该探索这些策略的能力，以提供弹性R. polycarpa对气候变化下盐度变化的影响。