The diversification and evolution of niche breadth across spatial scales in western North American monkeyflowers

Species show remarkable variation in ecological niche breadth, but the directionality of niche breadth evolution remains a question for niche axes across spatial scales. Testing the association between niche breadth evolution and the process of diversification could shed light on the role of ecology in the formation and maintenance of biodiversity. Here we applied Cladogenetic State change Speciation and Extinction models in western North American monkeyflowers (Mimulus sensu lato), with two states of niche breadth (generalist and specialist). We aimed to estimate the effects of niche breadth along broad-scale bioclimatic and local-scale microhabitat axes on diversification rate, and the evolutionary trend and mode of niche breadth. We found opposite patterns across spatial scales, with higher speciation rates detected for generalists along broad-scale bioclimatic axes and for specialists along local-scale microhabitat axes. Furthermore, we found weak trends towards specialization for b...

物种在生态位宽度上表现出显著变异，但生态位宽度进化的方向性在跨空间尺度的生态位轴上仍是未解之谜。检验生态位宽度进化与多样化过程之间的关联，有助于揭示生态学在生物多样性形成与维持中的作用。本文将分支发生状态变化的物种形成与灭绝模型（Cladogenetic State change Speciation and Extinction models）应用于北美西部的猴面花属植物（广义 Mimulus，Mimulus sensu lato），其生态位宽度分为广适性（generalist）与专适性（specialist）两种状态。我们旨在评估沿广域生物气候轴和局域微生境轴的生态位宽度对多样化速率的影响，以及生态位宽度的进化趋势与模式。研究发现，不同空间尺度下的模式截然相反：沿广域生物气候轴，广适性物种的物种形成速率更高；而沿局域微生境轴，专适性物种的物种形成速率更高。此外，我们还发现了向专适性进化的微弱趋势（原文此处未完整呈现：for b...）。