Mapping four decades of fire history for targeted conservation in the south-central highlands of Ethiopia

Abstract

The Bale Mountains of south-central Ethiopia comprise one of the largest and least studied mountain systems in Africa. An internationally recognized biodiversity hotspot, the region is home to Bale Mountains National Park and the Sanetti Plateau, which provide critical alpine habitat for numerous endemic and endangered species, such as the mountain nyala. Ethiopian agro-pastoralists in the region practice intentional burning to clear land for grazing and planting; however, pressures related to climate change and increasing populations have made understanding the frequency and extent of burning a top priority for conservationists and land managers seeking to balance conservation goals with the needs of local communities. To address this need, we mapped historical fire extent and frequency in the unique, high-altitude Ericaceous shrublands of Bale, using all available dry-season scenes from 42 years (1973-2015) of the Landsat record. We spatially and spectrally linked imagery within the LandsatLinkr R package to visualize landscape disturbances with a tasseled cap time series. A quantitative assessment of burned areas derived from the normalized burn ratio found that nearly all Ericaceous vegetation in the study area has burned since 1995, but with few repeated fires in the same location. Our results were not only in agreement with two MODIS Burned Area products and fire records compiled from the literature, but also improved upon their spatial resolution and augmented their temporal record. Maps and spatial data of fire date, extent, and frequency were disseminated to partners working in Ethiopia. These will support detailed studies of fire ecology in Bale and inform management approaches that ensure the preservation of the region's natural resources and the social-ecological systems they support.