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

为什么热带山区的物种比世界上其他山区多得多，这两个多世纪以来一直困扰着生物学家。一个长期以来被认为但研究很少的观点是，热带地区更高的海拔气候分层导致自然选择，选择热带山区比温带山区对气候耐受性更窄的生物。因此，假设生物在沿热带海拔梯度扩散时可能会遇到更多的气候障碍。在单一物种分裂成两个物种的过程中，种群的扩散限制和隔离是关键步骤。因此，热带山区可能存在更多新物种起源的机会，从而促进其高度物种丰富。这里提出的工作将比较热带和温带火蜥蜴的种群遗传结构和生理学，并将测试关于热带山区高生物多样性演化的两个关键问题：(I)与温带相比，热带海拔高度分散的种群之间是否发生较低的扩散？以及(Ii)不同气候条件下的生理特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，对于在全球迅速变化的情况下保护生物多样性至关重要。这项拟议的研究将有助于理解世界上一些地区的生物和进化过程？S：大多数物种丰富的生态系统可能会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S·贝尔自然历史博物馆合作，就气候变化对脆弱的山地动物的生物影响对非专家进行教育。

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.