Evolution of human-driven fire regimes in Africa

Sally Archibald, A. Carla Staver, Simon Asher Levin

Research output: Contribution to journalArticlepeer-review

169 Scopus citations

Abstract

Human ability to manipulate fire and the landscape has increased over evolutionary time, but the impact of this on fire regimes and consequences for biodiversity and biogeochemistry are hotly debated. Reconstructing historical changes in human-derived fire regimes empirically is challenging, but information is available on the timing of key human innovations and on current human impacts on fire; here we incorporate this knowledge into a spatially explicit fire propagation model. We explore how changes in population density, the ability to create fire, and the expansion of agropastoralism altered the extent and seasonal distribution of fire as modern humans arose and spread through Africa. Much emphasis has been placed on the positive effect of population density on ignition frequency, but our model suggests this is less important than changes in fire spread and connectivity that would have occurred as humans learned to light fires in the dry season and to transform the landscape through grazing and cultivation. Different landscapes show different limitations; we show that substantial human impacts on burned area would only have started ∼4,000 B.P. in open landscapes, whereas they could have altered fire regimes in closed/dissected landscapes by ∼40,000 B.P. Dry season fires have been the norm for the past 200-300 ky across all landscapes. The annual area burned in Africa probably peaked between 4 and 40 kya. These results agree with recent paleocarbon studies that suggest that the biomass burned today is less than in the recent past in subtropical countries.

Original languageEnglish (US)
Pages (from-to)847-852
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number3
DOIs
StatePublished - Jan 17 2012

All Science Journal Classification (ASJC) codes

  • General

Keywords

  • Fire spread model
  • Human evolution
  • Human ignition
  • Savanna

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