Nonlinear dynamics of fires in Africa over recent decades controlled by precipitation. (23rd June 2020)

• Record Type: Journal Article
• Authors: Wei, Fangli; Wang, Shuai; Fu, Bojie; Brandt, Martin; Pan, Naiqing; Wang, Cong; Fensholt, Rasmus
• Is Part Of: Global change biology. Volume 26:Number 8(2020)
• Page Start: 4495
• Page End: 4505
• Publication Date: 2020-06-23
• Subjects: African savanna -- drivers -- ensemble empirical mode decomposition method -- fire -- nonlinear dynamics -- precipitation -- turning points; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.15190
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Dynamics of fires in Africa are of critical importance for understanding changes in ecosystem properties and effects on the global carbon cycle. Given increasing fire risk from projected warming on the one hand and a documented human‐driven decline in fires on the other, it is still unknown how the complex interplay between climate and human factors affects recent changes of fires in Africa. Moreover, the impact of recent strong El Niño events on fire dynamics is not yet known. By applying an ensemble empirical mode decomposition method to satellite‐derived fire burned area, we investigated the spatio‐temporal evolution of fires in Africa over 2001–2016 and identified the potential dominant drivers. Our results show an overall decline of fire rates, which is continuous over the time period and mainly caused by cropland expansion in northern sub‐Saharan Africa. However, we also find that years of high precipitation have caused an initial increase in fire rates in southern Africa, which reversed to a decline in later years. This decline is caused by a high frequency of dry years leading to very low fuel loads, suggesting that recent drought causes a general reduction of burned areas, in particular in xeric savannas. In some mesic regions (10°–15°S), solar radiation and increased temperature caused increase in fires. These findings show that climate change overrules the impact of human expansion on fire rates at the continental scale in Africa, reducing the fire risk. Abstract : Our study revealed the nonlinear dynamics in fire burned area over 2001–2016 across the African continent, developed a change typology on fire burned area in space and over time, and explored the potential dominant drivers of observed fire changes. See Commentary on: https://onlinelibrary.wiley.com/doi/10.1111/gcb.16008 ; See also Letter to the Editor on: https://onlinelibrary.wiley.com/doi/10.1111/gcb.16021