Riparian forests are essential for stream ecological processes in arid and semiarid regions, however, they are often highly altered by the rapid expansion of urban areas. To maintain riparian ecosystems services, it is important to better understand the effects of urbanization on riparian forests. We quantified the three‐dimensional (3D) structure and woody species composition of a riparian corridor in Utah, USA, to evaluate patterns of vegetation along stream reaches that flow through distinct hydrologic domains (with gaining and losing reaches) and through a rapid rural‐to‐urban gradient. By using LiDAR imaging and field observations, we explore the extent to which the riparian vegetation structure follows patterns of topography linked to energy and water subsidies and patterns of human influence along the stream. Whereas natural reaches of Red Butte Creek were characterized by native vegetation and typical riparian species (e.g., Betula occidentalis), urbanized reaches had higher numbers of introduced plants (e.g., Acer platanoides) and more upland species (e.g., Quercus gambelii). Urban reaches were also characterized by exceptionally high trees (>18 m) in older residential neighbourhoods. In the natural area, canopy height was negatively correlated with height above the river (HAR). Additionally, we found higher cover and taller canopies on north‐facing aspects. These results show that LiDAR data, in combination with ground observations, can reveal strong influences of hydrology as well as land use in different canopy layers of riparian forests. We suggest that the decision making of individual landowners shapes vegetation beyond natural hydrological patterns, with implications for riparian forest management and restoration.

中文翻译：

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使用LiDAR评估北美西部沿农村到城市土地利用梯度的河岸植被结构的转变

河岸森林对于干旱和半干旱地区的河流生态过程至关重要，但是，由于城市地区的迅速扩张，河岸森林常常被高度改变。为了维持河岸生态系统服务，重要的是更好地了解城市化对河岸森林的影响。我们对美国犹他州河岸走廊的三维（3D）结构和木本物种组成进行了量化，以评估沿不同水文域（有或有和有损失）流经河流和快速农村地区的植被类型。到城市的渐变。通过使用LiDAR成像和野外观察，我们探索河岸植被结构遵循与能源和水补贴以及沿河人类影响模式相关的地形模式的程度。西化桦（Betula occidentalis），城市化河段的引种植物（例如，宏cer（Acer platanoides））数量更多，而陆生物种（例如，Quercus gambelii）则更多）。在较老的居民区中，城市河段的特征还在于高高的树木（> 18 m）。在自然区域，冠层高度与河流上方的高度（HAR）呈负相关。此外，我们在朝北的地方发现了较高的遮盖和较高的顶篷。这些结果表明，LiDAR数据与地面观测结果相结合，可以揭示水文学以及沿岸森林不同冠层的土地利用的强大影响。我们建议，单个土地所有者的决策会影响自然水文模式以外的植被，对沿岸森林的管理和恢复产生影响。