Paleoclimate history and its influence on ecosystem changes and human occupation/abandonment of East African high mountain ecosystems in Ethiopia

埃塞俄比亚东非高山生态系统的古气候历史及其对生态系统变化和人类占领/废弃的影响

• 批准号: 451220720
• 负责人: Professor Dr. Michael Zech
• 金额: --
• 依托单位: Professur für Physische Geographie mit Schwerpunkt Paläoumweltforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/451220720?language=en
• 关键词: Paleoclimate; history; its; influence; ecosystem

Periods of human occupation and abandonment in the afroalpine region of the Bale Mountains, Ethiopia, were very likely triggered at least partly by paleoclimate changes. This is suggested by first results obtained from a previous project. Within this follow-up project proposal, which accompanies the DFG Research Unit 2358 ‘The Mountain Exile Hypothesis’, it is therefore planned to contribute to the paleoclimate reconstruction of the study area. The results will be essential for complementing the full picture of ‘climate-human-environment interactions’ of the Research Unit 2358 and they will be interpreted in close interdisciplinary cooperation with the colleagues from the fields of archeology, pedology, paleoecology and glaciology.Work Package (WP) 1 will continue monitoring the isotopic signature of modern-day precipitation in order to better understand the modern-day atmospheric circulation patterns including their specific isotopic signatures affecting the Bale Mountains. This is justified given that isotope records in East Africa are usually interpreted in terms of ‘precipitation amount’. The actually responsible effect might, however, rather be a ‘source effect’. This is of utmost importance for the correct paleoclimatic interpretation of δ2H and δ18O records from the Bale Mountains as well as of other East African paleoclimate isotope records. WP2 aims at establishing a multi-proxy paleoclimate isotope record. The rationale here is that the so far established δ2Hn-alkane and δ18Osugar records from Lake Garba Guracha may not be unambiguously attributable to aquatic versus terrestrial sources. In order to test this, hyrax middens as unambiguous terrestrial archives (in close collaboration with Subproject P3 Paleoecology of the Research Unit 2358) as well as diatoms and the aquatic-derived biomarker dinosterol will be investigated. Last but not least, we will continue investigating sedimentary archives in close collaboration with the Subprojects P2 Anthrosols and P3 Paleoecology of the Research Unit 2358. Within WP3 we will analyze already retrieved and dated sediment and peat cores from the Wergoba Valley, the Sanetti Plateau and the Harena Forest in order to check for spatial and temporal heterogeneity of our paleoclimate proxy signals; within WP4 we will investigate presumably pre-LGM (last glacial maximum) and LGM cores from Lake Cheleleka in the close-by Arsi Mountains. Last but not least, WP5 will focus at highest possible resolution on the topmost core sections of Garba Guracha, for which human occupation/abandonment is most obviously confirmed by P1 Archeology, P2 Anthrosols and P3 Paleoecology.

埃塞俄比亚贝尔山脉的非洲高山地区的人类占领和遗弃时期很可能至少部分是由古气候变化引发的。这是从以前的一个项目获得的第一个结果建议。在这个后续项目建议书中，伴随着DFG研究单元2358“山流亡假说”，因此计划为研究区域的古气候重建做出贡献。这些结果对于补充2358研究单元的“气候-人类-环境相互作用”的全貌至关重要，它们将与考古学、土壤学、工作包（WP）1将继续监测现代降水的同位素特征，以更好地了解现代-一天的大气环流模式，包括其影响贝尔山脉的具体同位素签名。这是合理的，因为东非的同位素记录通常被解释为“降水量”。然而，实际上负责任的效应可能是一种“源效应”。这对于正确解释Bale山脉δ 2 H和δ 18 O记录以及其他东非古气候同位素记录的古气候至关重要。WP 2旨在建立多代用指标的古气候同位素记录。这里的理由是，迄今为止建立的δ 2 H正烷烃和δ 18 O糖记录加尔巴古拉查湖可能无法明确归因于水生与陆生来源。为了验证这一点，将对作为明确的陆地档案的蹄兔贝（与2358研究单位的子项目P3古生态学密切合作）以及硅藻和水生生物标志物二甾醇进行研究。最后但并非最不重要的是，我们将继续调查沉积档案与研究单位2358的子项目P2人为土壤和P3古生态学密切合作。在WP 3中，我们将分析已经检索和定年的沉积物和泥炭芯从Wergoba山谷，Sanetti高原和Harena森林，以检查我们的古气候代理信号的空间和时间异质性;在WP 4中，我们将调查大概前LGM（末次冰期最大）和LGM芯从Cheleleka湖附近的Arsi山脉。最后但并非最不重要的是，WP 5将以尽可能高的分辨率关注Garba Guracha最顶部的核心部分，其中人类的占领/遗弃最明显地得到了P1考古学，P2人为土壤和P3古生态学的证实。