Salt marshes can protect coastlines against flooding by attenuating wave energy and enhancing shoreline stabilization. However, salt-marsh functioning is threatened by human influences and sea level rise. Although it is known that protection services are mediated by vegetation, little is known about the role of vegetation structure in salt-marsh accretion. We investigated the role of vegetation presence, vegetation type and structural vegetation characteristics in sedimentation and sediment grain size. We established 56 plots on a salt marsh on the Dutch Wadden island of Texel. Plots were divided over four vegetation types contrasting in vegetation structure and varied in elevation and distance to creeks. Vegetation presence was controlled by clipping in subplots. Within each plot, we measured seven vegetation characteristics, sedimentation and the sediment grain size distribution. Furthermore, we explored the effect of the natural variation in vegetation structure on wave attenuation with a simple model approach. For this, we developed vegetation scenarios based on the field measurements of stem height, diameter and density. We found that vegetation presence increased sedimentation on average by 42%. Sedimentation was highest in Salicornia vegetation and increased with stem height and branching level. Grain size also seemed to increase with branching level. Modelled wave attenuation was 7.5 times higher with natural vegetation compared to topography only, was strongest for Spartina vegetation and most sensitive to the natural variance in stem density. Our results can be used to improve predictions of salt-marsh accretion and the implementation of salt marshes in nature-based flood defences.

盐沼可以通过减弱波浪能量和增强海岸线稳定性来保护海岸线免受洪水侵袭。然而，盐沼的功能受到人类影响和海平面上升的威胁。虽然已知保护服务是由植被介导的，但对植被结构在盐沼增生中的作用知之甚少。我们调查了植被存在、植被类型和结构植被特征在沉积和沉积物粒度中的作用。我们在荷兰瓦登特塞尔岛的盐沼上建立了 56 个地块。地块分为四种植被类型，植被结构不同，海拔和到小溪的距离各不相同。植被的存在是通过在子图中进行裁剪来控制的。在每个地块内，我们测量了七种植被特征，沉积物和沉积物粒度分布。此外，我们使用简单的模型方法探索了植被结构的自然变化对波浪衰减的影响。为此，我们根据茎高、直径和密度的现场测量开发了植被场景。我们发现植被的存在使沉积物平均增加了 42%。沉淀物最高Salicornia植被和随着茎高和分枝水平的增加而增加。晶粒尺寸似乎也随着分枝水平而增加。与仅地形相比，天然植被的模拟波衰减高出 7.5 倍，Spartina植被最强，对茎密度的自然变化最敏感。我们的结果可用于改进盐沼增生的预测以及盐沼在基于自然的防洪中的实施。