Evolution of grassland ecosystems during the Late Miocene in the Eastern Mediterranean

古植被的重建基本上是以古植物学记录为基础的，我们对欧亚大陆新近纪植被变化的认识主要依赖于有机植物遗迹，由于成岩作用，它们的保存有限。因此，景观和植被历史的许多重要方面，特别是在东地中海，仍然知之甚少。相比之下，主要是硅质植物化石(植硅体)在缩小我们在新近纪植被历史方面的文献和知识差距方面显示出很大的优势，因为它们的成岩持久性，特别是在富碳酸盐、碱性和氧化条件下。因此，植硅体通常提供了在干旱条件下优先生长的植物的存在的证据，在大型植物学或孢粉学记录(如草)中没有或很少有记录。此外，植物硅体可以识别比许多花粉更低的分类水平(例如，区分C3和C4草)，从而帮助解决更完整的植物和植被变化的图景，特别是在新生时期的草原历史问题。在我们的项目中，我们对地中海东部中新世晚期(9-6 Ma)的草原生态系统演化进行了高分辨率和多代理研究，结合孢粉学、木炭、碳同位素和沉积学/土壤学。我们的初步结果已经表明，至少在最近的托尔顿期(Pikermian Biome)，C4草在欧洲东南部的植被中发挥了主要作用。我们的项目旨在解开该地区草原和林地(包括火的作用)的复杂演化史，并将进一步为重建欧洲最后一批中新世原始人居住的景观(植被)做出独特贡献。

The reconstruction of palaeovegetation is essentially based on palaeobotanical records and our understanding of the Neogene changes of vegetation in Eurasia dominantly rest upon organic floral remains, which has limited preservation due to diagenesis. As a result, many important aspects of landscape and vegetation history, especially in the Eastern Mediterranean, are still poorly understood. In contrast, primarily siliceous plant fossils (phytoliths) show a high advantage to close our gaps of documentation and knowledge in Neogene vegetation history, because of their diagenetical durability especially under carbonate rich, alkaline and oxygenized conditions. Therefore, phytoliths often provide evidence for the presence of plants growing preferentially under xeric conditions and are not or only rarely documented in the macrobotanical or palynological record (e.g. grasses). Furthermore, phytoliths allow identifying plants to lower taxonomic levels than many pollen would (e.g. distinction of C3 and C4 grasses), thereby helping to resolve a more complete picture of floral and vegetation change, especially issues of grassland histories, in a certain region especially during the Neogene.In our project we perform high-resolution and multi-proxy studies on grassland ecosystem evolution during the Late Miocene (9-6 Ma) in the Eastern Mediterranean, using phytoliths in combinations with palynology, charcoal, carbon isotopy and sedimentology/pedology. Our preliminary results already show that C4-grasses play a major role in SE-European vegetation at least during the latest Tortonian (Pikermian Biome). Our project intend to disentangle the complex evolutionary history of grasslands and woodlands (including the role of fire) in this region, and will further provide unique contributions to the reconstruction of landscapes (vegetation) inhabited by the last Miocene hominids in Europe.