Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Rua Professor Artur Riedel, 275, Diadema, SP, 09972-270, Brazil.
Department of Ornithology, Division of Vertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024-5192, USA.
Evolution. 2021 Oct;75(10):2371-2387. doi: 10.1111/evo.14318. Epub 2021 Aug 26.
The role of historical factors in establishing patterns of diversity in tropical mountains is of interest to understand the buildup of megadiverse biotas. In these regions, the historical processes of range fragmentation and contraction followed by dispersal are thought to be mediated by the interplay between rugged relief (complex topography) and climate fluctuations and likely explain most of the dynamics of diversification in plants and animals. Although empirical studies addressing the interaction between climate and topography have provided invaluable insights into population divergence and speciation patterns in tropical montane organisms, a more detailed and robust test of such processes in an explicit spatio-temporal framework is still lacking. Consequently, our ability to gain insights into historical range shifts over time and the genomic footprint left by them is limited. Here, we used niche modeling and subgenomic population-level datasets to explore the evolution of two species of warbling finches (genus Microspingus) disjunctly distributed across the Montane Atlantic Forest, a Neotropical region with complex geological and environmental histories. Population structure inferences suggest a scenario of three genetically differentiated populations, which are congruent with both geography and phenotypic variation. Demographic simulations support asynchronous isolation of these populations as recently as ∼40,000 years ago, relatively stable population sizes over recent time, and past gene flow subsequent to divergence. Throughout the last 800,000 years, niche models predicted extensive expansion into lowland areas with increasing overlap of species distributions during glacial periods, with prominent retractions and isolation into higher altitudes during interglacials, which are in line with signs of introgression of currently isolated populations. These results support a dual role of cyclical climatic changes: population divergence and persistence in mountain tops during warm periods followed by periods of expansion and admixture in lower elevations during cold periods. Our results underscore the role of the interplay between landscape and climate as an important mechanism in the evolution of the Neotropical montane biota.
历史因素在建立热带山地多样性模式中的作用，有助于了解生物多样性的形成。在这些地区，范围碎裂和收缩随后扩散的历史过程被认为是由崎岖的地形（复杂的地形）和气候波动之间的相互作用介导的，这可能解释了动植物多样化的大部分动态。虽然解决气候和地形相互作用的实证研究为热带山地生物的种群分化和物种形成模式提供了宝贵的见解，但在明确的时空框架中对这些过程进行更详细和稳健的测试仍然缺乏。因此，我们了解随时间推移的历史范围变化以及它们留下的基因组足迹的能力受到限制。在这里，我们使用生态位模型和亚基因组种群水平数据集来探索两种鸣禽（Microspingus 属）的进化，它们分布在安第斯山脉大西洋森林的断裂带，这是一个具有复杂地质和环境历史的新热带地区。种群结构推断表明存在三个遗传分化的种群的情景，这与地理和表型变异一致。人口动态模拟支持这些种群最近在约 40000 年前的异步隔离，最近的人口规模相对稳定，以及随后的分歧后的基因流。在过去的 800000 年中，生态位模型预测了在冰川时期物种分布重叠不断增加的情况下，广泛扩展到低地地区，在间冰期期间，物种分布明显退缩并隔离到较高海拔地区，这与当前隔离种群的基因渗入迹象一致。这些结果支持周期性气候变化的双重作用：在温暖时期山顶的种群分化和持续，随后在寒冷时期在较低海拔地区的扩张和混合。我们的研究结果强调了景观和气候相互作用作为新热带山地生物进化的重要机制的作用。
