Humans and climate modulate fire activity across Ethiopia

Abstract

Background: Fire occurrence is influenced by interactions between human activity, climate, and fuels that are difficult to disentangle but crucial to understand, given fire’s role in carbon dynamics, deforestation, and habitat maintenance, alteration, or loss. To determine the relative balance of climatic and anthropogenic influences on fire activity, we quantified interannual variability in burned area across Ethiopia from 2001 to 2018 and developed a statistical model to assess climate and human factors contributing to patterns of area burned. Results: Annual burned area declined nationally and within several regions from 2001 to 2018 and was closely related to climate, particularly antecedent temperature. Of the area that burned at least once, 62% reburned at 1–3-year intervals and the geographic region of frequent-fire areas did not shift over time. Despite increased enforcement of a fire ban over the past 20 years, no strong spatiotemporal shifts in fire occurrence patterns were detected at a national level. Conclusions: Our results suggest that human influence combined with dynamics of vegetation and fuels strongly influenced fire occurrence in Ethiopia, indicating that geographic variation in cultural fire practices was highly influential and relatively unchanging between 2001 and 2018. In contrast, interannual variability in total burned area was strongly related to climate and the influence of climate on fuel abundance. Our results highlight that climate can strongly influence short-term variability in fire activity even as longer-term patterns may depend more strongly on human influence.