In recent decades the dynamics of global change in developed countries has led to significant alterations in the hydrological and sediment dynamics of terraced land. Agricultural terraces were built to control overland flow and prevent erosion, acting as buffers and barriers throughout the sediment cascading system. Their abandonment and degradation increase the sensitivity of the catchment, promoting the collapse of dry-stone walls and the reworking of stored sediment. In this study, a geomorphometric Index of Connectivity (IC) –derived from high-resolution LiDAR data (0.9 pt m^-2, RMSE < 0.2 m)– analysed the spatial patterns of structural connectivity in a small Mediterranean catchment (4.8 km²) characterized by a massive presence of terraces (37% of the surface area). The morphological characteristics of these anthropogenic features generated a dual effect: (1) general disconnectivity between different compartments of the catchment and (2) concentration of water and sediment flows along preferential pathways promoted by a cascade effect of collapse within the terraced areas. The fieldwork found that 73% of wall collapses were located on these pathways that showed high IC values (>Q8). This spatial matching was related to feedback dynamics between structural and functional connectivity, in which the failure of walls increases the concentration of runoff, which in turn accelerates the hydraulic processes causing their collapse. Identifying the most connected pathways within the most vulnerable structures in an integrated analysis could be a cost-effective strategy for establishing priority areas for the management of terraced lands.

中文翻译：

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梯田沉积物连通性的空间格局：流域敏感性的人为控制。

在最近的几十年中，发达国家的全球变化动态导致梯田的水文和沉积物动态发生了重大变化。建立了农业梯田，以控制陆上水流并防止侵蚀，在整个沉积物级联系统中充当缓冲带和屏障。它们的废弃和退化增加了集水区的敏感性，促进了干石墙的倒塌和储存的沉积物的再加工。在这项研究中，从高分辨率LiDAR数据（0.9 pt m ^-2，RMSE <0.2 m）得出的连通性（IC）地貌指数-分析了地中海小流域（4.8 km ^2）的结构连通性的空间格局），其特征是大量的梯田（占地面的37％）。这些人为特征的形态学特征产生了双重影响：（1）集水区不同隔间之间的普遍不连通性；（2）梯田内塌陷的级联效应促进沿优先途径集中的水和沉积物流动。现场调查发现，有73％的墙体塌陷位于这些路径上，这些路径显示出较高的IC值（> Q8）。这种空间匹配与结构和功能连通性之间的反馈动力学有关，其中壁的破坏增加了径流的集中度，这反过来又加速了导致其塌陷的水力过程。