Wildfire Effects on Savannah Ecosystem in The Northern Part of Ghana Amidst a Changing Climate

Abstract

Wildfires in Ghana's part of the Northern Savannah zone have recently become a primary environmental and socio-economic concern due to climate change and human activities. The aftermath of such a fire can be stretched toward species composition, vegetation structure, and resilience in ecosystem services. For that reason, a careful consideration of its impact and management strategies is imperative. This work systematically evaluated wildfire management strategies at national and local scales, wildfire drivers and impacts were examined, and the effects of wildfires on Northern Ghana's ecosystem structural diversity and vegetation dynamics were assessed. Using a mixed-method approach combining remote sensing data from MODIS-NDVI ground truthing to understand the status of area wildfires from 2000 to 2021, this research analysed climatic variables from 1992 to 2022 relevant to temperature, humidity, and wind speed with fire patterns. Additionally, species composition was studied across frequently burned and non-burned plots, considering fire-tolerant and fire-sensitive species. The analysis used OLS and GWR models to anchor our understanding of the spatial pattern of the wildfires and their driving factors, such as land use and proximity to settlements. The findings reveal that within the study area, active fires number 432,153, with the highest in West Gonja and Mamprugu Moagduri. At the same time, the most significant wildland fire occurrence predictors were proximity to the settlements, slope gradient and temperature, and the most influential was maximum temperature at p < 0.01. Fire-resistant species, such as Vitellaria paradoxa and Parkia biglobosa, were abundant in most areas affected by the fire. The populations of fire-intolerant species, such as Khaya senegalensis, declined considerably. Species richness was 15% lower in the frequently burned areas, and there was a significant shift towards shrubland expansion at the expense of forest cover. The study also identified a decreased burned area over time, p = 0.015, although no significant trend in fire frequency, p = 0.499, was detected. Wildfires threaten savannah ecosystems by reducing biodiversity, altering vegetation, and degrading ecosystem services, with human activities and climate change intensifying their impact. However, integrating wildfire prevention into climate policies, afforestation, controlled burning, and early warning systems can enhance ecosystem resilience in Ghana’s savannah zone.