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

两个多世纪以来，为什么热带山区比世界上其他山区拥有更多的物种一直困扰着生物学家。一个长期以来，但研究很少的想法是，热带地区更大的海拔气候分层导致自然选择热带地区的生物比温带山区的生物具有更窄的气候耐受性。 因此，有人假设，生物可能会遇到更多的气候障碍，扩散沿着热带海拔梯度。 种群的扩散限制和隔离是一个物种分裂成两个物种的过程中的关键步骤。 因此，热带山区可能存在更多的新物种起源的机会，从而促进其高物种丰富度。 这里提出的工作将比较种群遗传结构和生理学的热带和温带蝾螈，并将测试两个关键问题，在热带山区的高生物多样性的演变：（一）较低的扩散发生在海拔分离的人口之间的热带相比，温带？不同气候条件下的生理特化程度与种群间扩散的速率之间是否存在关系？了解为什么物种多样性在地球上分布不均匀，对于在快速的全球变化中保护生物多样性至关重要。 拟议中的研究将是有价值的了解如何生物和进化过程中的一些世界？世界上物种最丰富的生态系统可能会受到全球气候变化的影响。 首席研究员也将与明尼苏达大学合作？贝尔自然历史博物馆，教育非专业人士了解气候变化对脆弱的山地动物群的生物影响。

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.