The study attempts to assess the retreat of a section of a bounding sea cliff promontory, exposed to wave forcing from both sides, of an important Mediterranean sea-turtle nesting beach, within a Mediterranean marine protected area (Gerakas, Zakynthos Island, Greece). Morphological changes were monitored within a 2-year period using a terrestrial laser scanner and the findings were compared with those from historical ortho-photographs to estimate sea cliff erosion the last 20 years. An advanced wave model supplemented by a model for cliff notch evolution, as well as an analytical model were also used to estimate cliff erosion due to wave attack. Comparisons of sea cliff profiles and calculations of volumetric changes using the collected and historical topographic data showed an average annual recession of about 0.16 m for the period 1997–2016. By comparison, coastal modeling estimated a retreat of about 0.23 m/yr, whereas a 0.14–0.3 m/y recession was assessed by the analytical approach; this reasonable discrepancy with the empirical results, is probably caused, amongst others, by the fact that the models does not account for the protection of cliff toes by a constant supply of erosion debris from above. The wave model was also used to estimate sea cliff retreat rates under a 0.5 m sea level rise and showed a fourfold increase compared with the current recession rate. On the basis of these results, as well as considerations related to the seismicity of the study area, it appears that the factors responsible for the sea cliff retreat are wave action, precipitation-induced surface flows, and earthquake-related instabilities that may cause rapid, large-scale erosion. The outcomes of this study are highlighting the critical interplay of several natural factors and climatic change effect on driving coastal erosion, which consequently results in the loss of ecologically critical habitats, thereby challenging conservation goals and management effectiveness.

中文翻译：

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界定生态重要海滩的海崖海角的侵蚀状况

这项研究试图评估在地中海海洋保护区（希腊扎金索斯岛，格拉卡斯）内重要的地中海海龟嵌套海滩的包围海崖海角一部分的退缩，该海角从两侧暴露于强迫作用下。使用地面激光扫描仪在2年内对形态变化进行了监测，并将发现的结果与历史正射照片的结果进行了比较，以估算最近20年的海崖侵蚀情况。还使用了高级波浪模型，并辅以悬崖缺口演化模型以及解析模型来估计由于波浪袭击而引起的悬崖侵蚀。使用收集的和历史的地形数据比较海崖剖面和计算体积变化，结果表明，1997-2016年期间的平均年衰退量约为0.16 m。相比之下，海岸模型估计的退缩量约为0.23 m / yr，而分析方法评估的退缩量为0.14-0.3 m / y。这种与经验结果的合理差异，可能是由于以下事实造成的：模型没有考虑到从上方持续供应侵蚀性碎屑对悬崖脚趾的保护。波浪模型还用于估计海平面上升0.5 m时的海崖退缩率，并且与当前的衰退率相比增加了四倍。根据这些结果，以及与研究区域的地震活动性有关的考虑因素，似乎导致海崖撤退的因素包括波浪作用，降水引起的地表流动以及与地震有关的不稳定性，这些因素可能会导致地震的迅速发生。 ，大规模侵蚀。