Are mountains "higher" in the tropics? A comparative analysis of population genetic structure and ecophysiological divergence in montane salamanders

为什么热带山区比世界上其他山区拥有更多的物种，这个问题困扰了生物学家两个多世纪。一个长期存在但研究很少的观点是，热带地区较高的海拔气候分层导致自然选择热带地区比温带山区对气候耐受性更窄的生物。因此，假设生物沿着热带海拔梯度扩散时可能会遇到更多的气候障碍。种群的分散限制和隔离是单个物种分化为两个物种过程中的关键步骤。因此，热带山区可能存在更多的新物种起源机会，从而促进其物种丰富度。这里提出的工作将比较热带和温带蝾螈的种群遗传结构和生理，并将测试关于热带山区高生物多样性演变的两个关键问题：(i)与温带相比，热带地区海拔分离的种群之间的分散程度是否较低？（二）不同气候条件下的生理专门化程度与种群间的扩散速度之间是否存在关系？了解物种多样性在地球上分布不均的原因，对于在全球快速变化的情况下保护生物多样性至关重要。拟议的研究将是有价值的，以了解生物体和进化过程是如何在一些世界？大多数物种丰富的生态系统可能受到全球气候变化的影响。首席研究员还将与明尼苏达大学合作。在贝尔自然历史博物馆向非专业人士传授气候变化对脆弱的山地动物的生物影响。

Why tropical mountains harbor so many more species than other mountainous areas of the world has puzzled biologists for more than two centuries. A long-held, but poorly studied idea is that greater elevational climatic stratification in the tropics leads to natural selection for organisms with narrower climatic tolerances in tropical than temperate mountains. As a result, it is hypothesized that organisms might encounter more climatic barriers to dispersal along tropical elevational gradients. Dispersal limitation and isolation of populations are key steps in the process by which a single species splits into two species. Consequently, more opportunities for new species to originate might exist in tropical mountains, thereby promoting their high species richness. The work proposed here will compare the population genetic structure and physiology of tropical and temperate salamanders and will test two key questions regarding the evolution of high biodiversity in tropical mountains: (i) Does lower dispersal occur between elevationally separated populations in the tropics compared to the temperate zone? and (ii) Is there a relationship between the degree of physiological specialization for different climatic conditions and the rate at which dispersal occurs between populations? Understanding why species diversity is distributed unevenly across the earth is critical for preserving biodiversity in the face of rapid global change. The proposed research will be valuable for understanding how organisms and evolutionary processes in some of the world?s most species-rich ecosystems might be impacted by global climate change. The principal investigator will also work with the University of Minnesota?s Bell Museum of Natural History to educate non-specialists on the biological impacts of climate change on delicate montane faunas.