Seagrass loss can be partially attributed to naturally- or anthropogenically-induced sediment dynamics that involve excessive burial or erosion processes. The main goal of this work was to develop a modelling approach for analysing bottom morphological changes on Sites of Community Importance (SCIs) characterized by the presence of meadows. Sediment dynamics (settling fluxes) and composition (grain size and mineralogy) within the two SCIs of the Civitavecchia coastal zone (north-eastern Tyrrhenian, Italy) were investigated using sediment traps and bottom sediment samples. Moreover structural, morphological, and dynamic parameters of meadows were analyzed. The results showed high reliability in reproducing the settling fluxes of medium and coarser sands (the most abundant sediment fractions of the two SCIs) compared to the corresponding fluxes estimated with sediment traps. To further confirm the accuracy of the proposed approach, a significant relationship was shown to exist between bottom morphological changes reproduced by the numerical model and plant rhizome growth as measured by sampling; this relationship attests to the capacity of to withstand burial and erosion processes. The model allowed us to perform a high spatial resolution evaluation of erosion levels and deposition processes that occur within the two SCIs, providing a predictive and useful tool towards a more sustainable management and conservation strategy of meadows in coastal zones.

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评估 Posidonia oceanica 草甸埋藏和侵蚀过程的建模方法

海草损失部分归因于自然或人为引起的沉积物动力学，其中涉及过度掩埋或侵蚀过程。这项工作的主要目标是开发一种建模方法，用于分析以草地存在为特征的群落重要地点 (SCI) 的底部形态变化。使用沉积物收集器和底部沉积物样本对奇维塔韦基亚沿海地区（意大利第勒尼安东北部）两个 SCI 内的沉积物动态（沉降通量）和成分（粒度和矿物学）进行了研究。此外还分析了草甸的结构、形态和动态参数。结果表明，与沉积物捕集器估计的相应通量相比，再现中砂和粗砂（两个 SCI 中最丰富的沉积物部分）的沉降通量具有较高的可靠性。为了进一步证实该方法的准确性，数值模型再现的底部形态变化与采样测量的植物根茎生长之间存在显着关系；这种关系证明了其承受掩埋和侵蚀过程的能力。该模型使我们能够对两个 SCI 内发生的侵蚀水平和沉积过程进行高空间分辨率评估，为沿海地区草甸的更可持续管理和保护战略提供了预测性和有用的工具。