Plant diversity changes at the southeastern Tibetan Plateau during the last 21 ka and its drivers

青藏高原东南部近21ka植物多样性变化及其驱动因素

• 批准号: 410561986
• 负责人: Dr. Stefan Kruse
• 金额: --
• 依托单位: Forschungsstelle Potsdam
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410561986?language=en
• 关键词: Plant; diversity; changes; southeastern; Tibetan

The preservation of the unique Tibetan plant diversity requires an understanding of its drivers. Cli-mate, natural disturbances and land use, the potential diversity drivers are spatially highly correlated. Thus, their specific effects on plant alpha diversity and their interactions can hardly be separated ap-plying a modern ecological approach that targets spatial gradients. Accordingly, we propose to perform a palaeoecological study focusing on the Late Glacial and Holocene plant alpha diversity change.We hypothesize that (H1) plant alpha diversity measures (richness, dominant taxa num-ber) on the eastern Tibetan Plateau shows complex spatio-temporal trends during the Late Glacial and Holocene. We expect that (H2) richness is related to landscape structure, which itself is a function of natural disturbances (wildfire, erosion) and human impact. Furthermore, we hypothesize that (H3) the dominant taxa number is mainly related to vegetation type driven by climate change and human im-pact.Our study will make use of proxy information gained from the analyses of lake sediments. It will combine the collection of new palaeoenvironmental data at three key sites (located along altitudi-nal transect at the southeastern Tibetan Plateau margin) and palaeoenvironmental data synthesis from the eastern Tibetan Plateau and surrounding area (25-40°N, 90-105°E). Interpretation of palaeo-environmental data will be based on relationships between modern environmental information and proxy information as derived from a lake sediment training set comprising 234 sites. At key sites, pol-len and sedimentary ancient DNA (plant metabarcoding) will be investigated as proxies for past pat-tern in plant alpha diversity and vegetation type. Independent information on past climate change will be inferred from stable oxygen isotopes measurements of sedimentary diatom silica and proxy-climate data synthesis. Natural disturbances and land use will be inferred from a multi-proxy approach including the analyses of proxies for fire, soil erosion, and land use. With respect to the synthesis study, an already available pollen data set will be used and complemented with further proxy data. Finally, by developing a novel modelling approach we aim to disentangle the relationship between alpha diversity measures, vegetation type and landscape structure, climate, natural disturbances and land use.Our research has the potential to identify critical thresholds in drivers of plant diver-sity that when crossed cause a tremendous and/or even irreversible diversity loss.

保护西藏独特的植物多样性需要了解其驱动因素。气候、自然干扰和土地利用等潜在多样性驱动因子在空间上高度相关。因此，它们对植物α多样性的具体影响和它们之间的相互作用很难通过以空间梯度为目标的现代生态学方法来分离。因此，我们建议对青藏高原东部晚冰期-全新世植物α多样性变化进行古生态学研究，并假设青藏高原东部晚冰期-全新世（H1）植物α多样性指标（丰富度、优势类群数）表现出复杂的时空变化趋势。我们预计（H2）丰富度与景观结构有关，景观结构本身是自然干扰（野火，侵蚀）和人类影响的函数。此外，我们还假设（H3）优势类群的数量主要与气候变化和人类活动影响下的植被类型有关。它将联合收割机在三个关键地点（沿着青藏高原东南缘的海拔样带）收集新的古环境数据和青藏高原东部及周边地区（25-40°N，90-105°E）的古环境数据合成。对古环境数据的解释将以现代环境信息与从一个由234个地点组成的湖泊沉积物训练集得出的代用信息之间的关系为基础。在关键地点，将调查花粉和沉积古DNA（植物元条形码）作为植物α多样性和植被类型过去模式的替代物。关于过去气候变化的独立信息将从沉积硅藻二氧化硅的稳定氧同位素测量和代用气候数据合成中推断出来。自然干扰和土地利用将推断从多代理的方法，包括代理分析火灾，土壤侵蚀和土地利用。在综合研究方面，将使用现有的花粉数据集，并补充更多的代用数据。最后，通过开发一种新的建模方法，我们的目标是解开阿尔法多样性措施，植被类型和景观结构，气候，自然干扰和土地利用之间的关系，我们的研究有可能确定关键阈值的驱动程序的植物多样性，当越过造成巨大的和/或甚至不可逆转的多样性损失。