Spatio-temporal Dynamics of Bushfires in The Gadabedji Biosphere Reserve

Abstract

In Niger, bushfires pose a serious threat to food security and biodiversity. The Gadabedji Biosphere Reserve, located north of the Maradi Region in the Sahelian savanna zone of central Niger, is particularly threatened, notably by late and uncontrolled fires. This study aimed to better understand the severity of bush fires in the RBG between 1993 and 2023. More specifically, it analyzes the spatio-temporal distribution of fires and burned surfaces within the RBG reserve and identifies the main factors explaining this distribution. To achieve this, medium-resolution satellite data were used, namely Landsat-5 & 4 Thematic Mapper images, Landsat-7 Enhanced Thematic Mapper, and Operational Land Imager, corresponding to the periods before and after the fires. A marked periodicity of extreme fire years is observed, notably in 2003 and 2023. However, in 2013, the intensity remained low. The central zone is particularly vulnerable to fires and accounts for nearly 80% of the active fires detected across its entire surface. The annual burned surface rate varies, depending on the scale, from 0.05% to 7.33% for the studied area and from 0.01% to 40% within the central zone. The topomorphology of the study area influences the propagation of bush fires: burned areas are primarily found at medium and high altitudes, on slopes and sectors with high density of herbaceous cover. To mitigate the severity and impacts, it is necessary to develop adapted risk management plans to be implemented before, during, and after bush fires.