Rivers are conduits for aquatic organisms and host an exceptional number of species. Over geologic time, rivers and the aquatic organisms that live in them are subject to changes in topography that can alter where rivers flow. Differences in erosion rates across drainage divides cause some river basins to grow and others to shrink. Occasionally, rivers are abruptly rerouted by river captures that create both new dispersal corridors and barriers for aquatic organisms. These changes in habitat connectivity can lead to the evolution of new species, which has prompted suggestions that river captures may be a mechanism to produce high freshwater biodiversity. We test this hypothesis by building a model, Bio‐SLANT (Biodiversity on Simulated LAndscapes using Neutral Theory). Bio‐SLANT couples a computational landscape model that simulates river basin reorganization to a macroevolutionary model that simulates the dispersal, speciation, and extinction of organisms. We first show that modeled basin area exerts a primary control on within‐basin species richness due to the species‐area relationship. We then describe the effects of drainage area exchange between river basins. River capture increases species richness, but only temporarily, whereas elevated rates of speciation and extinction provide a persistent biological record of river network reorganization. When river captures are frequent, speciation rates increase more than extinction rates, resulting in a positive diversification rate under most of the biological parameters tested. We explore the implications of our results for species richness in landscapes with basins of different relative sizes and for diversification in tectonically active and inactive settings.

中文翻译：

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模拟流域水生生物的演化

河流是水生生物的管道，拥有众多物种。在地质时期内，河流和生活在其中的水生生物的地貌变化会改变河流的流向。跨排水沟的侵蚀率差异导致一些流域增长而其他流域萎缩。有时，河流捕获会突然改变河流的路线，从而为水生生物创造新的扩散通道和屏障。栖息地连通性的这些变化可能导致新物种的进化，这提示河流捕获可能是产生高淡水生物多样性的一种机制。我们通过建立模型Bio-SLANT（使用中立理论对模拟景观进行生物多样性）来检验该假设。Bio-SLANT将模拟流域重组的计算景观模型与模拟生物扩散，物种形成和灭绝的宏观进化模型相结合。我们首先表明，由于物种与面积的关系，流域模型对流域内物种丰富度起着主要控制作用。然后我们描述流域之间流域交换的影响。河流捕获增加了物种丰富度，但只是暂时的，而物种形成和灭绝的速率提高为河流网络重组提供了持久的生物学记录。当河流捕获频繁时，物种形成速率比灭绝速率增加得更多，因此在大多数测试的生物参数下，正形成多样化速率。