Abstract Freshwater mussels are ecosystem engineers that provide important ecosystem functions and services, such as bio-filtration. A method for quantifying filtration capacity in rivers was developed and applied in a case study that estimated the loss in filtration services provided by invasive alien dreissenid mussels following a mass mortality event in the river Meuse in the Netherlands. Mass mortality resulted from a sudden water level drop caused by damage to a weir during severe winter conditions. The low water level allowed an assessment of dreissenid densities on river groynes. Imagery acquired by an unmanned aerial vehicle (UAV) was used to construct 3D images of groynes and to determine surface areas inhabited by mussels. A bootstrapping approach was applied to assess the loss of filtration capacity due to the mass mortality event. The filtration capacity of dreissenids on groynes was sufficient to filter 0.3% to 12.3% of the discharge in a 25 km impounded stretch of the river Meuse during high and low discharges, respectively. On average, 3.6% of the discharge could be filtered by dreissenids on the groynes. Mortality on air exposed groynes was 100% leading to a full loss of dreissenid filtration capacity at these locations. Initial recolonization of groynes formerly exposed to air was observed 17 months after the low water event, ultimately leading to a recovery of the filtration capacity.

中文翻译：

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对侵入性德莱森贻贝大量死亡后过滤服务的损失进行量化

摘要 淡水贻贝是生态系统工程师，提供重要的生态系统功能和服务，如生物过滤。在一项案例研究中开发并应用了一种量化河流过滤能力的方法，该研究估计了在荷兰默兹河发生大规模死亡事件后入侵的外来德莱森贻贝提供的过滤服务损失。在严冬条件下，堰被损坏导致水位突然下降，导致大量死亡。低水位允许评估河流上的德莱森密度。无人机 (UAV) 获取的图像用于构建 groynes 的 3D 图像并确定贻贝栖息的表面积。应用自举方法来评估由于大量死亡事件导致的过滤能力损失。在 25 公里长的默兹河蓄水段中，在高流量和低流量期间，德莱森在 groynes 上的过滤能力足以分别过滤 0.3% 至 12.3% 的流量。平均而言，3.6% 的排泄物可以被腹股沟上的德莱森植物过滤。暴露在空气中的 groynes 的死亡率为 100%，导致这些位置的德莱森过滤能力完全丧失。在低水事件发生 17 个月后，观察到以前暴露在空气中的 groynes 的初始重新定植，最终导致过滤能力的恢复。暴露在空气中的 groynes 的死亡率为 100%，导致这些位置的德莱森过滤能力完全丧失。在低水事件发生 17 个月后，观察到以前暴露在空气中的 groynes 的初始重新定植，最终导致过滤能力的恢复。暴露在空气中的 groynes 的死亡率为 100%，导致这些位置的德莱森过滤能力完全丧失。在低水事件发生 17 个月后，观察到以前暴露在空气中的 groynes 的初始重新定植，最终导致过滤能力的恢复。