DOI: 10.1016/j.quascirev.2016.08.009
论文题名: Disentangling the impacts of climate and human colonization on the flora and fauna of the Australian arid zone over the past 100 ka using stable isotopes in avian eggshell
作者: Miller G.H. ; Fogel M.L. ; Magee J.W. ; Gagan M.K.
刊名: Quaternary Science Reviews
出版年: 2016
卷: 151 起始页码: 27
结束页码: 57
语种: 英语
英文关键词: Abrupt
; Amino acid racemization
; Arid zone
; Australia
; Ecosystem
; Extinction
; Paleoclimatology
; Stable isotopes
Scopus关键词: Animals
; Arid regions
; Birds
; Continuous time systems
; Ecology
; Ecosystems
; Glacial geology
; Isotopes
; Lakes
; Light extinction
; Moisture
; Rain
; Stream flow
; Abrupt
; Amino acid racemizations
; Arid zones
; Australia
; Paleoclimatology
; Stable isotopes
; Climate change
; amino acid
; aridity
; bird
; carbon isotope
; climate change
; colonization
; ecosystem service
; eggshell
; fauna
; flora
; grass
; Last Glacial
; Last Glacial Maximum
; oxygen isotope
; paleoclimate
; paleoenvironment
; Pleistocene
; racemization
; stable isotope
; Australia
; Aves
; Dromaius
; Genyornis
; Poaceae
英文摘要: Throughout the Quaternary, the flora and fauna of Australia evolved and adapted to the high-amplitude, low- and high-frequency climate changes that characterized the ice-age cycles. However, during the last glacial cycle, between ∼120 and 15 ka, unprecedented irreversible changes in flora and fauna occurred, and in that same interval modern humans established their first firm presence in the landscape. Disentangling the impacts of the first-order trend toward a colder, drier planet through the Late Quaternary from the impacts of human colonization has been challenging, from both the chronological and paleoenvironmental perspectives. We utilize the stable isotopes of carbon and oxygen preserved in near-continuous time series of Dromaius (emu) eggshell from five regions across Australia to provide independent reconstructions of ecosystem status and climate over the past 100 ka. Carbon isotopes are determined by the diet consumed by the female bird, whereas oxygen isotopes record the status of local moisture balance in the months prior to breeding. Together, δ13C and δ18O provide ecosystem status and climate from the same dated sample, reducing correlation uncertainties between proxies. Combined with recent improvements in the chronologies of Late Quaternary shorelines fringing inland lake basins and deflation during arid times, these data collectively reaffirm that Australia generally became increasingly, albeit irregularly, drier from the last interglaciation through to the last glacial maximum. Dromaius eggshell δ18O documents peak aridity between 30 and 15 ka, but shows no evidence of exceptional climate change between 60 and 40 ka. In contrast, Dromaius δ13Cdiet documents an irreversible loss of the majority of palatable summer-rainfall-related C4 grasses across the Australian arid zone between 50 and 45 ka, about the same time that the giant megafaunal bird, Genyornis, became extinct, and coincident with human dispersal across the continent. Our data indicate that changes unique to Australia occurred between 50 and 45 ka that led to a new climate-vegetation relationship and an overall reduction in effective moisture across much of the continent. The large summer-rainfall-dominated lakes of interior Australia failed to re-fill subsequently, despite a wide range of global climate states. A full explanation for the mechanisms behind these changes remains elusive, but they are almost certainly related to human agency. Plausible explanations include a change in fire regime resulting from human-lit fires, a change in fire regime following extinction of megafaunal browsers, and/or a threshold response to increasing aridity. Of these, the climate change explanation is least likely, given the lack of evidence for unprecedented aridity between 60 and 40 ka, and the successful adaptation of Australian ecosystems to 2.5 Ma of similar changes. © 2016 Elsevier Ltd 资助项目: Miller, G.H.
; University of ColoradoUnited States
; 电子邮件: gmiller@colorado.edu
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59414
Appears in Collections: 过去全球变化的重建
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作者单位: University of Colorado, Boulder, CO, United States; Curtin University, Perth, WA, Australia; University of California MercedCA, United States; Australian National University, Australia
Recommended Citation:
Miller G.H.,Fogel M.L.,Magee J.W.,et al. Disentangling the impacts of climate and human colonization on the flora and fauna of the Australian arid zone over the past 100 ka using stable isotopes in avian eggshell[J]. Quaternary Science Reviews,2016-01-01,151