The importance of the uplift of the Qinghai-Tibetan Plateau for the diversity of alpine plants

• Applicant: Professorin Dr. Alexandra Nora Müllner-Riehl
• Subject Area: Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2012 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 224581182

Biodiversity is unevenly distributed on Earth. There are several factors which can lead to high species diversity in an area, like e.g. age of the area (accumulation of species over time), dispersal asymmetries (more immigration than emigration due to more favourable conditions in one area compared to another area), higher diversification rates (due to intrinsic or extrinsic reasons), or a combination thereof. The opening of new ecological niches following major changes in the environment (e.g. orographic changes) may constitute an important driver for the diversification of species of higher elevation habitats. The project proposed here aims at unveiling the spatio-temporal framework of the evolution of alpine plants, using the species-rich genus Saxifraga (Saxifragaceae) as a model, in the light of global climate change and geological history from Palaeocene to Pleistocene. First, we will investigate the effect of the uplift of the Qinghai-Tibetan Plateau (QTP) and its associated climatic changes on the diversification of alpine species. To understand the floristic exchanges between the QTP and other mountain systems of the world, we will also study the dispersal history of this genus. Finally, we will identify important ecological factors for the diversification of Saxifraga. By combining multi-gene phylogenies with biogeographic analyses, set in a temporal context by fossil constraints for Saxifragaceae and relatives, we want to answer the following questions: (1) How old is the crown group of Saxifraga? Was diversification in Saxifraga associated with the uplift of the Qinghai-Tibetan Plateau? (2) What is the relative contribution of immigration versus in situ diversification to the high species diversity of Saxifraga in the Qinghai-Tibetan Plateau and neighbouring regions? Furthermore, together with information on the geographical and ecological attributes of species (distribution range; ecological/climate space) and knowledge about the geological history of the distributional areas, we want to answer the following questions: (3) Do sympatric sister taxa have a stronger niche separation than allopatric sister taxa? Is niche conservatism or niche divergence dominant in Saxifraga? (4) Are hybridising species in Saxifraga ecologically and genetically differentiated? What are the ecological factors involved in the divergence of these species? The results of this project will also serve as source of information for setting up IUCN Red List assessments for species under threat. In addition, DNA data of Saxifraga might potentially act as barcodes for the identification of cryptic species and other taxa of under-studied species complexes that exist in Saxifraga. Herbarium Lipsiense at Leipzig University and its partner institutions will greatly benefit from the new plant collections made in Asia during the course of this project.

• DFG Programme: Research Grants
• Participating Person: Dr. Adrien Favre