Although tidal marshes are known for their coastal defense function during storm surges, the impact of extreme wave forcing on tidal marsh development is poorly understood. Seedling survival in the first season after germination, which may involve exposure to extreme wave events, is crucial for the natural establishment and human restoration of marshes. We hypothesize that species-specific plant traits plays a significant role in seedlings survival and response to wave induced stress, i.e., through stem bending and uprooting. To test this hypothesis, seedlings of pioneer species (Bolboschoenus maritimus, Schoenoplectus tabernaemontani, Spartina anglica, and Puccinellia maritima) with contrasting biophysical traits were placed in the Large Wave Flume in Hannover (Germany) and exposed to storm wave conditions. Seedlings of P. maritima and S. anglica experienced a lower loss rate and bending angle after wave exposure compared to S. tabernaemontani and especially B. maritimus. The higher loss rates of B. maritimus and S. tabernaemontani result from deeper scouring around the stem base. Scouring depth was larger around stems of greater diameter and higher resistance to bending. Here, B. maritimus and S. tabernaemontani have both thicker and stiffer stems than S. anglica and P. maritima. Our results show that especially seedlings with thicker stems suffer from erosion and scouring, and have the highest risk of being lost during extreme wave events. This implies that for successful seedling establishment and eventually the establishment of a mature tidal marsh vegetation, the species composition and their capacity to cope with storm wave disturbances is crucial.

中文翻译：

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生存最厚？极端波浪强迫对沼泽幼苗的影响由物种形态介导

尽管潮汐沼泽以其在风暴潮期间的海岸防御功能而闻名，但人们对极端波浪强迫对潮汐沼泽发展的影响知之甚少。发芽后第一个季节的幼苗存活率可能涉及暴露于极端波浪事件，对于沼泽的自然建立和人类恢复至关重要。我们假设特定物种的植物性状在幼苗存活和对波浪诱导的压力（即通过茎弯曲和连根拔起）的反应中起着重要作用。为了检验这一假设，先锋树种苗木（Bolboschoenus maritimus，水葱，大米草和星星袍) 具有对比的生物物理特征被放置在汉诺威（德国）的大波浪水槽中，并暴露在风暴波浪条件下。幼苗P. maritima的和大米草相比经历了较低损失率和弯曲角度波曝光后S. tabernaemontani和尤其B. maritimus。B. maritimus和S. tabernaemontani的较高损失率是由于茎基部周围更深的冲刷造成的。直径较大且抗弯曲性较高的茎周围的冲刷深度较大。这里，B. maritimus和S. tabernaemontani兼得厚且更硬比茎大米草和P. maritima。我们的结果表明，特别是茎较粗的幼苗会遭受侵蚀和冲刷，并且在极端波浪事件中丢失的风险最高。这意味着对于成功的幼苗建立并最终建立成熟的潮汐沼泽植被，物种组成及其应对风暴波干扰的能力至关重要。