Data from: Vegetation as self-adaptive coastal protection: reduction of current velocity and morphologic plasticity of a brackish marsh pioneer

By reducing current velocity, tidal marsh vegetation can diminish storm surges and storm waves. Conversely, currents often exert high mechanical stresses onto the plants and hence affect vegetation structure and plant characteristics. In our study, we aim at analysing this interaction from both angles. On the one hand, we quantify the reduction of current velocity by Bolboschoenus maritimus, and on the other hand, we identify functional traits of B. maritimus' ramets along environmental gradients. Our results show that tidal marsh vegetation is able to buffer a large proportion of the flow velocity at currents under normal conditions. Cross-shore current velocity decreased with distance from the marsh edge and was reduced by more than 50% after 15 m of vegetation. We were furthermore able to show that plants growing at the marsh edge had a significantly larger diameter than plants from inside the vegetation. We found a positive correlation between plant thickness and cross-shore current which could provide an adaptive value in habitats with high mechanical stress. With the adapted morphology of plants growing at the highly exposed marsh edge, the entire vegetation belt is able to better resist the mechanical stress of high current velocities. This self-adaptive effect thus increases the ability of B. maritimus to grow and persist in the pioneer zone and may hence better contribute to ecosystem-based coastal protection by reducing current velocity.

潮汐盐沼植被可通过降低水流流速削弱风暴潮与风暴浪。反之，水流常会对植株施加高强度机械应力，进而影响植被结构与植株性状。本研究旨在从双向视角解析这一相互作用：一方面量化滨海藨草（Bolboschoenus maritimus）对水流流速的削弱效果，另一方面识别滨海藨草分株沿环境梯度的功能性状。研究结果表明，正常工况下潮汐盐沼植被可缓冲大部分水流流速；横岸流速随距盐沼边缘的距离增加而降低，在经过15米植被带后，流速降幅超50%。此外，本研究发现盐沼边缘生长的植株直径显著大于植被带内部的植株；植株粗度与横岸流速呈正相关，这在机械应力较高的生境中可赋予植株适应优势。生长于高暴露盐沼边缘的植株具有适应性形态特征，使得整个植被带能够更好地抵御高流速水流带来的机械应力。这种自适应效应提升了滨海藨草在先锋带生长与定居的能力，进而可通过降低水流流速，更好地助力基于生态系统的海岸防护工作。