On the timing of megafaunal extinction and associated floristic consequences in Australia through the lens of functional palaeoecology

• Published in: Quaternary Science Reviews
• Main Authors: Adeleye, M. A., Andrew, S. C., Gallagher, Rachael V. (R20502), van der Kaars, S., De Deckker, P., Hua, Q., Haberle, S. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: U.K., Elsevier 2023
• Subjects: XXXXXX - Unknown; Planktonic foraminifera
• Online Access: https://doi.org/10.1016/j.quascirev.2023.108263; https://hdl.handle.net/1959.7/uws:73275

The timing and cause of megafaunal extinctions are an enduring focus of research interest and debate. Despite the developments in the analysis of coprophilous fungal spores (CFS), the proxy for reconstructing past megaherbivore changes, the environmental consequences of this fauna loss remain understudied. This is partly due to the general obscurity of such a signal in pollen records, as well as limitations in disentangling human and extinction ecological impact, and the lack of spatial information of megafauna changes in site-level sedimentary records. In Australia, the debate centres on the possibility that habitat loss through climate change, vegetation-fire change, human intervention, or a combination of these factors led to the extinction of some large animals during the Late Pleistocene. Pollen and plant isotope studies have also demonstrated that vegetation-fire responses following the Late Pleistocene megafaunal extinctions were characterized by increased vegetation density and fire activity due to reduced grazing/browsing pressure. Here, we use a well-dated marine sedimentary core record from the Murray Darling Basin in southern Australia and apply palynological and functional palaeoecological approaches to reconstruct the Late Pleistocene megafaunal abundance changes, the timing and potential cause of extinction across the basin and investigate if extinction was associated with any signal of trait-based vegetation changes. We infer megafaunal abundance changes from the abundance of CFS and compare this with climatic proxies from the same core. We then link modern observations of fruit, seed and fire response traits of plant genera within the basin to the fossil pollen record to reconstruct palaeo vegetation community traits and determine if extinction was associated with any changes in plant community trait composition. Closely-spaced 14C dates obtained from planktonic foraminifera and δ18O tie points place a major decline in CFS, and thus the timing of extinction, within the basin at ∼43.3 ka. While ...