A fiery past: A comparison of glacial and contemporary fire regimes on the Palaeo-Agulhas Plain, Cape Floristic Region

QUATERNARY SCIENCE REVIEWS

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Article

Kraaij, Tineke^1,2  Engelbrecht, Francois³  Franklin, Janet⁴  Cowling, Richard M.² 

[1] Nelson Mandela Univ, Sch Nat Resource Management, Private Bag X6531, ZA-6530 George, Western Cape, South Africa

[2] Nelson Mandela Univ, African Ctr Coastal Palaeosci, POB 77000, ZA-6031 Port Elizabeth, Western Cape, South Africa

[3] Univ Witwatersrand, Global Change Inst, ZA-2193 Johannesburg, Gauteng, South Africa

[4] Univ Calif Riverside, Dept Bot & Plant Sci, 900 Univ Ave, Riverside, CA 92521 USA

关键词: Data analysis;    Fire danger weather severity;    Fire frequency;    Fire seasonality;    Fynbos shrublands;    McArthur forest fire danger index;    Paleoclimatology;    Pleistocene;    Regional climate downscaling;    Southern Africa;   

DOI  :  10.1016/j.quascirev.2019.106059

来源: Elsevier

【 摘 要 】

Landscape-level fire governs vegetation structure and composition in the contemporary Cape Floristic Region (CFR) and was key to the existence of Middle Stone-Age hunter gatherers on the Palaeo-Agulhas Plain (PAP). However, virtually nothing is known about Pleistocene fire regimes of the CFR. We characterized the fire danger climate of the PAP during the Last Glacial Maximum (LGM; 19-26 ka BP) based on palaeo-climate simulations and explored the severity and seasonality of fire danger weather along west-east and coastal-inland gradients across the PAP. We used knowledge of relationships between contemporary fire climate and contemporary CFR fire regimes to propose LGM fire regimes in relation to simulated LGM fire climate. We found that the severity of fire weather during the LGM across the PAP was significantly higher than present; mean fire danger index scores and the incidence of high fire danger days were greater, while the seasonality of fire weather was more pronounced, exhibiting summer-autumn fire regimes across the PAP. Although a more severe fire climate suggests potentially more frequent fires than present, slower fuel accumulation due to colder temperatures, reduced solar radiation and lower atmospheric CO2 may have partly countered this effect. Our proposed LGM fire regimes predict the vegetation of the PAP to have been dominated by fire tolerant, largely Mediterranean-climate formations such as fynbos, renosterveld and grassland, but is unlikely to have provided a driver for mass seasonal east-west migration of large grazers on the PAP. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

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