Tracing the impact of the Andean uplift - Evolution of St. John's wort (Hypericum L.) in South America: historical biogeography, character evolution, niche shifts and age estimations

点击翻译按钮获取中文摘要

Changing environments have always been a driving force of evolution. In the South American mountain ranges, an extraordinary high diversity of flowering plant species has evolved since the northern Andean Cordilleras have started to uplift 7-14 million years (Ma) ago. Several studies have shown the major impact ofthese mountain uplifts in the outstanding diversification of the Neotropical flora. The medicinally interesting genus Hypericum (St. John's wort, Hypericaceae) is an important member ofthe Andean vegetation at higher altitudes. With more than 25% of its species in these high altitude habitats, Hypericum has a main center of diversity in the Andes. Recent phylogenetic studies in Hypericum verified the Nootropic species as a monophyletic group. Further insights into the evolutionary history of the Nootropic Hypericum species is limited by low sample availability and lack of detailed field observations. Based on the newly obtained samples a nested DNA-based phylogenetic analysis will be performed. The obtained results will give detailed insights into biogeography of South American Hypericum. This in turn, will be used to trace ecological shifts and the influence of repeated climate changes on evolution within Hypericum in this area. The investigation will significantly contribute to our understanding of the evolutionary history of habitats in the Andes in general and mechanisms influencing plant diversity on a global scale.