Comparative Phylogeography of 12 Widespread Tropical Rainforest Tree Species

热带雨林拥有地球上物种最丰富的植物组合，然而产生这种多样性的过程却鲜为人知。这项拟议中的研究调查了在整个热带美洲和西非发现的12种雨林树种的遗传过程，这些物种导致了物种形成。该研究的重点是(1)热带山脉作为传播障碍的重要性；(2)区域森林历史对物种遗传多样性水平的影响；(3)非洲和热带美洲之间的生物交换。这项研究将检验两种截然不同的假设，即广泛分布的热带树种要么是遗传上具有凝聚力的种群，要么是具有高度遗传分化的物种复合体。热带森林正受到农业扩张和气候变化的严重压力。为了保护热带阔叶树的遗传多样性，有必要了解遗传多样性在种内和种间是如何分配的。该研究强调了地理因素在遗传变异分布中的作用，并将为木棉（Ceiba pentandra）和轻木（Ochroma pyramidale）等重要物种确定遗传变异的生物地理中心。这项研究涉及与史密森尼热带研究所以及拉丁美洲和非洲机构的合作。

Tropical rainforests contain the most species-rich plant assemblages on Earth, yet the processes that generate this diversity are poorly understood. The proposed research investigates genetic processes leading to speciation in 12 rainforest tree species found throughout tropical America and, for three species, West Africa. The study is focused on (1) the importance of tropical mountains as barriers to dispersal, (2) effects of regional forest histories on levels of genetic diversity within species, and (3) biotic interchange between Africa and the tropical America. This research will test the contrasting hypotheses that widespread tropical tree species are either genetically cohesive populations or species complexes with high levels of genetic divergence.Tropical forests are under severe pressure from agricultural expansion and climate change. In order to conserve genetic diversity of tropical hardwoods it is essential to understand how genetic diversity is partitioned within and among species. The proposed research highlights the role of geography in shaping the distribution of genetic variation, and it will pinpoint biogeographic centers of genetic variation for important species such as kapok (Ceiba pentandra) and balsa (Ochroma pyramidale). The research involves collaboration with the Smithsonian Tropical Research Institute and Latin American and African institutions.