Abstract Gravel-bed rivers exhibit remarkable dynamics and distinctive morphological patterns which influence the biological processes, as well as the river ecosystem resilience to human impacts. Classifications of river ecosystems into groups with morphologically distinct patterns are therefore of paramount importance for a better understanding of their dynamics, their management and conservation. Investigations on fluvial morphology and the related dynamics in Chilean gravel-bed rivers are still scarce, and, so far, no efforts have been made to identify latitudinal patterns of their morphological characteristics that may serve as a basis for further classification purposes. In fact, the great variability in bio-geographic, climatic, geologic and geomorphologic settings of the country offer an almost unique opportunity to study how the morphological characteristics of gravel-bed rivers may vary within extremely heterogeneous environments. We performed a regional analysis of nineteen Chilean gravel-bed rivers, from semi-arid Mediterranean to rainy temperate conditions (latitude ranging from 32° S to 39° S). Planform characteristics within these reaches were identified through interpretation of satellite images. Topographic features of the river basins were derived from open source digital elevation models and water discharge values were obtained from available national databases. We addressed the following research questions: a) can these 19 rivers be grouped into clusters considering their distinct planform characteristics of the river channel and basin features, as related to latitudinal gradients?, b) do river morphological characteristics vary along the analyzed latitudinal gradient?, c) does the distribution of specific geomorphic units (i.e. islands) follow a longitudinal pattern?, and finally, d) are these units associated to specific hidrogeomorfic characteristics? We generated a clustering which reflects latitudinal and morphological gradients in Chilean gravel-bed rivers, with the northernmost and southernmost rivers grouped according to their distinctive hydro-morphological characteristics and geomorphic units. We also observed a general tendency of an increase in the proportion of fluvial islands relative to the active channel area from the 33° Latitude in southward direction.

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智利砾石层河流的形态特征是否表现出纬度模式？

摘要 砾石床河流表现出显着的动态和独特的形态模式，影响生物过程，以及河流生态系统对人类影响的恢复能力。因此，将河流生态系统分类为具有不同形态模式的组对于更好地了解其动态、管理和保护至关重要。对智利砾石床河流的河流形态和相关动力学的调查仍然很少，并且到目前为止，还没有努力确定其形态特征的纬度模式，可以作为进一步分类的基础。事实上，生物地理、气候、该国的地质和地貌环境提供了一个几乎独特的机会来研究砾石层河流的形态特征在极其异质的环境中如何变化。我们对 19 条智利砾石床河流进行了区域分析，从半干旱的地中海到多雨的温带条件（纬度范围从 32° S 到 39° S）。这些河段的地貌特征是通过对卫星图像的解释来确定的。流域的地形特征来自开源数字高程模型，排水量值来自可用的国家数据库。我们解决了以下研究问题：a) 考虑到这 19 条河流不同的河道和流域特征的平面特征，是否可以将它们分组？与纬度梯度有关？，b）河流形态特征是否沿着分析的纬度梯度变化？，c）特定地貌单位（即岛屿）的分布是否遵循纵向模式？最后，d）这些单位是否与特定的水化地貌特征？我们生成了一个反映智利砾石层河流的纬度和形态梯度的聚类，最北端和最南端的河流根据其独特的水文形态特征和地貌单位进行分组。我们还观察到从南纬 33° 向南，河流岛屿的比例相对于活动河道面积增加的总体趋势。c) 特定地貌单元（即岛屿）的分布是否遵循纵向模式？最后， d) 这些单元是否与特定的地貌特征相关？我们生成了一个反映智利砾石层河流的纬度和形态梯度的聚类，最北端和最南端的河流根据其独特的水文形态特征和地貌单位进行分组。我们还观察到从南纬 33° 向南，河流岛屿的比例相对于活动河道面积增加的总体趋势。c) 特定地貌单元（即岛屿）的分布是否遵循纵向模式？最后， d) 这些单元是否与特定的地貌特征相关？我们生成了一个反映智利砾石层河流的纬度和形态梯度的聚类，最北端和最南端的河流根据其独特的水文形态特征和地貌单位进行分组。我们还观察到从南纬 33° 向南，河流岛屿的比例相对于活动河道面积增加的总体趋势。d) 这些单位是否与特定的水化地貌特征相关？我们生成了一个反映智利砾石层河流的纬度和形态梯度的聚类，最北端和最南端的河流根据其独特的水文形态特征和地貌单位进行分组。我们还观察到从南纬 33° 向南，河流岛屿的比例相对于活动河道面积增加的总体趋势。d) 这些单位是否与特定的水化地貌特征相关？我们生成了一个反映智利砾石层河流的纬度和形态梯度的聚类，最北端和最南端的河流根据其独特的水文形态特征和地貌单位进行分组。我们还观察到，从南纬 33° 向南，河流岛屿的比例相对于活动河道面积有增加的总体趋势。