云南文山晚中新世植物群及其环境演变与植物多样性变化的相关性

Past geological events deeply impacted modern biodiversity. Miocene is considered the most critical interval in the build-up of the modern world with major uplift of modern mountain chains, the initiation of bipolar glaciations, the origin of modern ocean currents, the aridification of the continental interiors, the overall cooling trend of the global climate and the reduction in atmospheric CO2 levels. In the same period, the Himalayas uplift and monsoon system starts and develops in Eastern Asia. Fossils reveal how geological events impacted on modern biodiversity. A set of plant fossils including, leaves, fruits and seeds, even flowers were recently uncovered from late Miocene of Wenshan, Yunnan China. This material is new and has never been reported before. These fossils are well preserved and many morphological detailed are visible on the fossils. Fossil material belongs to Xiaolongtan formation and its geological age is late Miocene based on the information of the local geological structure, stratigraphy, mammal fossil, and pollen assemblage. This fossil assemblage is called Wenshan flora. Wenshan flora comprises more than 50 genera, such as: Betula, Zelkova, Rosa, Acer, Ailanthus, Cinnamomum, Sloanea, Engelhardia, etc. based on primary identifications. The genera Betula, Zelkova, Rosa, Acer, Ailanthus are temperate elements whereas Sloanea, Engelhardia, Fokienia, etc. are subtropical element. Zelkova is the main component. Composition of Wenshan flora is quite different from Xiaolongtan flora, even if Xiaolongtan flora is of same geological age of Wenshan flora and about 150 km west of it. Main elements of Xiaolongtan flora are: Fagaceae, mainly Cyclobalanopsis and Lithocarpus, Lauraceae, mainly Cinnamomum, Litsea, Phoebia, Fabaceae, mainly Albizia, Cassia, Dalbergia, and Erythrophleum. Xiaolongtan flora is a subtropical flora. In order to reveal the correlation between geological events and modern plant biodiversity, the following scientific questions are addressed: Why are the two floras so different? What is the composition Wenshan flora? What kind of paleoclimate and paleoaltitude it has? To answer these questions, five research directions are designed in the current project; they are: reconstruction of floristics and vegetation of Wenshan flora, biogeography of Zelkova, reconstruction of paleoclimate and paleoaltitude, comparison between Wenshan flora and Xiaolongtan flora. Approaches based on leaf architecture, cuticle analysis, leaf margin analysis, climate-leaf analysis multivariate program and coexistence will be employed in this project. The following targets will be achieved in this project: precise composition and vegetation type, paleoclimatic parameters and paleoaltitude of Wenshan flora, explanations of distribution patterns of Zelkova and Sequoia, and reasons of differences of Wenshan flora and Xialongtan flora. Nine papers will be published and four Ph.D. students will be trained based on this ?project.

申请人在云南文山新近系小龙潭组地层中发现一批从未被报道过的植物化石（文山植物群），这些化石保存精美在全国新生代地层都不多见。初步鉴定表明这该植物群有桦木属、榉属、蔷薇属、槭属、臭椿属、樟属、猴欢喜属、红杉属等至少50个属以上，是一个常绿落叶混交的植物群。本项目通过植物化石与现代植物类群的叶结构对比和角质层分析，准确鉴定这些化石，重建文山植物群的面貌，讨论主要成分榉属的分布区演变的过程；采用叶缘分析法、气候-叶片多变量分析程序和共存分析法定量重建文山植物群古气候要素；用湿静态能平衡原理重建文山植物群古海拔，并与相邻同时代的小龙潭植物群对比。本项目的开展对揭示云南晚中新世植物区系的差异以及植被类型分异的原因，植物多样性形成和演变的规律，探索植物多样性对环境变化的响应等问题都有重要意义，为应对全球变化对生物多样性影响提供重要的地质学证据。项目将发表论文9篇，其中SCI论文7篇，培养博士研究生4名

项目基于申请人在云南文山新近级地层中发现一批从未被报道过的植物化石（文山植物群）展开。按照计划任务书的要求，项目开展了全面深入的野外工作，获得植物化石5000余件，通过系统古植物学的研究，共识别维管植物33科51属64种(含化石新种19种)。其中被子植物30科47属59种，发表新种9种，基本掌握了文山植物群的面貌。通过古植被的重建，认为中新世文山植物群由非石灰岩植被和石灰岩植被两大类5种植被类型组成。重建了文山植物群所代表的古气候，认为在中中新世，该地区的古气候特征是：东亚的气候带的南亚热带-北热带的过渡区域之间，表明其中中新世时更为温暖，季风已经建立，但是强度弱于现在。对红杉、马蹄荷、十大功能等类群的地理分布格局进行了讨论，提出了季风气候是驱动植被和生物多样性演变的主要驱动力的观点。项目发表SCI论文18篇，其中第一标注论文10篇，在国际古植物学、植物学大会上做口头报告4人次，培养博士研究生4名，一名博士研究生参与了项目的研究工作，项目实现了预期目标。