Abstract Ephemeral rivers are key features of desert ecosystems, providing shallow groundwater and occasional surface flow, but compared to perennial systems, the structure of riparian forests in ephemeral rivers and their interactions with the hydrologic regime are poorly understood. This study examines the distribution of riparian woody species in the ephemeral Kuiseb River in central Namibia. Unmanned aerial vehicle (UAV) and satellite imagery were used to examine the structure of the riparian forest across lateral and longitudinal gradients. Woody plant abundance peaked in the terminal alluvial zone, the reach of the river where floods typically run dry. The five dominant species exhibited similar spatial patterns at latitudinal and longitudinal scales. Faidherbia albida and Salvadora persica were found more proximal to the active channel and concentrated in the terminal alluvial zone. Acacia (Vachellia) erioloba, Euclea pseudebenus, and Tamarix usneoides were more evenly dispersed laterally across the riparian zone and along the river's longitudinal profile. These spatial patterns correspond to plant physiological properties of hydrological dependence and gradients of water availability and soil composition. The tight coupling of plant distributions with water availability highlights the need for long-term monitoring of ephemeral riparian vegetation in light of potential future changes to the global hydrologic regime.

中文翻译：

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利用遥感技术研究纳米比亚一条短暂河流沿岸植被的横向和纵向分布

摘要 短命河流是沙漠生态系统的关键特征，提供浅层地下水和偶尔的地表水流，但与多年生系统相比，短命河流中的河岸森林结构及其与水文状况的相互作用知之甚少。本研究调查了纳米比亚中部短暂的 Kuiseb 河沿岸木本物种的分布。无人机 (UAV) 和卫星图像用于跨横向和纵向梯度检查河岸森林的结构。木本植物的丰度在终端冲积区达到顶峰，这是河流通常洪水枯竭的地方。五个优势物种在纬度和纵向尺度上表现出相似的空间格局。Faidherbia albida 和 Salvadora persica 被发现更靠近活动河道，并集中在终端冲积带。Acacia (Vachellia) erioloba、Euclea pseudebenus 和 Tamarix usneoides 更均匀地横向分布在河岸带和沿河流的纵向剖面。这些空间模式对应于水文依赖性的植物生理特性以及可用水量和土壤成分的梯度。鉴于全球水文状况的潜在未来变化，植物分布与可用水量的紧密耦合凸显了对短暂的河岸植被进行长期监测的必要性。Tamarix usneoides 更均匀地横向分布在河岸带和沿河流的纵向剖面。这些空间模式对应于水文依赖性的植物生理特性以及可用水量和土壤成分的梯度。鉴于全球水文状况未来可能发生的变化，植物分布与可用水量的紧密结合凸显了对短暂的河岸植被进行长期监测的必要性。Tamarix usneoides 更均匀地横向分布在河岸带和沿河流的纵向剖面。这些空间模式对应于水文依赖性的植物生理特性以及可用水量和土壤成分的梯度。鉴于全球水文状况未来可能发生的变化，植物分布与可用水量的紧密结合凸显了对短暂的河岸植被进行长期监测的必要性。