Feedbacks between geomorphic processes and riparian vegetation in river systems are an important control on fluvial morphodynamics and on vegetation composition and distribution. Invasion by nonnative riparian species alters these feedbacks and drives management and restoration along many rivers, highlighting a need for ecogeomorphic models to assist with understanding feedbacks between plants and fluvial processes, and with restoration planning. In this study, we coupled a network-scale sediment model (Sediment Routing and Floodplain Exchange; SeRFE) that simulates bank erosion and sediment transport in a spatially explicit manner with a recruitment potential analysis for a species of riparian vegetation (Arundo donax) that has invaded river systems and wetlands in Mediterranean climates worldwide. We used the resulting ecogeomorphic framework to understand both network-scale sediment balances and the spread and recruitment of A. donax in the Santa Clara River watershed of Southern California. In the coupled model, we simulated a 1-year time period during which a 5-year recurrence interval flood occurred in the mainstem Santa Clara River. Outputs identify key areas acting as sources of A. donax rhizomes, which are subsequently transported by flood flows and deposited in reaches downstream. These results were validated in three study reaches, where we assessed postflood geomorphic and vegetation changes. The analysis demonstrates how a coupled model approach is able to highlight basin-scale ecogeomorphic dynamics in a manner that is useful for restoration planning and prioritization and can be adapted to analogous ecogeomorphic questions in other watersheds.

中文翻译：

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将沉积物建模与入侵河岸植被动力学耦合的生态地貌框架

河流系统中地貌过程与河岸植被之间的反馈是对河流形态动力学和植被组成和分布的重要控制。非本地河岸物种的入侵改变了这些反馈并推动了许多河流沿线的管理和恢复，强调需要生态地貌模型来帮助理解植物和河流过程之间的反馈以及恢复规划。在这项研究中，我们将网络尺度沉积物模型（沉积物路由和洪泛区交换；SeRFE）与一种河岸植被（Arundo donax）的补充潜力分析相结合，以空间明确的方式模拟河岸侵蚀和沉积物输送) 已侵入全球地中海气候中的河流系统和湿地。我们使用的结果ecogeomorphic框架，以了解双方网络规模的沉淀余额和蔓延和招聘A.竹圣克拉拉流域南加州。在耦合模型中，我们模拟了 1 年的时间段，在此期间，主干圣克拉拉河发生了 5 年一遇的洪水。输出确定了作为A. donax来源的关键区域根状茎，随后被洪水运输并沉积在下游河段。这些结果在三个研究河段得到验证，我们评估了洪水后的地貌和植被变化。该分析展示了耦合模型方法如何能够以一种对恢复规划和优先排序有用的方式突出流域尺度的生态地貌动态，并且可以适用于其他流域中的类似生态地貌问题。