Predicting the Potential Impact of Climate Change on Carbon Stock in Semi-Arid West African Savannas

Abstract

West African savannas are experiencing rapid land cover change that threatens biodiversity and affects ecosystem productivity through the loss of habitat and biomass, and carbon emissions into the atmosphere exacerbating climate change effects. Therefore, reducing carbon emissions from deforestation and forest degradation in these areas is critical in the efforts to combat climate change. For such restorative actions to be successful, they must be grounded on a clear knowledge of the extent to which climate change affects carbon storage in soil and biomass according to different land uses. The current study was undertaken in semi-arid savannas in Dano, southwestern Burkina Faso, with the threefold objective of: (i) identifying the main land use and land cover categories (LULCc) in a watershed; (ii) assessing the carbon stocks (biomass and soil) in the selected LULCc; and (iii) predicting the effects of climate change on the spatial distribution of the carbon stock. Dendrometric data (Diameter at Breast Height (DBH) and height) of woody species and soil samples were measured and collected, respectively, in 43 plots, each measuring 50 × 20 m. Tree biomass carbon stocks were calculated using allometric equations while soil organic carbon (SOC) stocks were measured at two depths (0–20 and 20–50 cm). To assess the impact of climate change on carbon stocks, geographical location records of carbon stocks, remote sensing spectral bands, topographic data, and bioclimatic variables were used. For projections of future climatic conditions, predictions from two climate models (MPI-ESM-MR and HadGEM2-ES) of CMIP5 were used under Representative Concentration Pathway (RCP) 8.5 and modeling was performed using random forest regression. Results showed that the most dominant LULCc are cropland (37.2%) and tree savannas (35.51%). Carbon stocks in woody biomass were higher in woodland (10.2 ± 6.4 Mg·ha−1) and gallery forests (7.75 ± 4.05 Mg·ha−1), while the lowest values were recorded in shrub savannas (0.9 ± 1.2 Mg·ha−1) and tree savannas (1.6 ± 0.6 Mg·ha−1). The highest SOC stock was recorded in gallery forests (30.2 ± 15.6 Mg·ha−1) and the lowest in the cropland (14.9 ± 5.7 Mg·ha−1). Based on modeling results, it appears clearly that climate change might have an impact on carbon stock at horizon 2070 by decreasing the storage capacity of various land units which are currently suitable. The decrease was more important under HadGEM2-ES (90.0%) and less under MPI-ESM-MR (89.4%). These findings call for smart and sustainable land use management practices in the study area to unlock the potential of these landscapes to sequestering carbon.

Local perceptions of anthropogenic and climate factors affecting the use and the conservation of Detarium microcarpum and Detarium senegalense in Burkina Faso (West Africa)

“…The broad spectrum of applications for these species confirms their importance in supporting rural livelihoods (Houénon et al, 2021; Sreekumar et al, 2020). Dimobe et al (2018) identified Detarium species among the priority multipurpose species in Burkina Faso, a designation also accorded to other species like A. africa (Balima et al, 2018) and B. costatum (Zerbo et al, 2022).…”

Modeling gas exchange and biomass production in West African Sahelian and Sudanian ecological zones

“…These sites are located in Senegal, Benin, Mali, Ghana, Niger, and Burkina Faso covering overall 70 years of observations within the 1984-2018 period (not continuous for all sites). A total of 24 sites in Senegal (20 grassland and 4 savanna woodlands) that were monitored between 1999 and 2017 were provided by the Centre de Suivi Ecologique (CSE; Diouf et al, 2015). Data from four sites with contributions of trees as well as grasses (Eguerit, Hombori Hondo, Tara, and Timbadior) and one millet site (Bilantao) were obtained from the Gourma region in Mali, representing a precipitation gradient from 300 to 450 mm yr −1 .…”

Land use configuration shapes climate change risk to gallery forests in a savannah ecosystem

“…This is a problem because, despite their relatively small extent, gallery forests are crucial for the overall functioning of savannah ecosystems, e.g. providing dry season refuges for birds and amphibians as well as habitat for forest-dwelling species, and storing significant amounts of carbon (Johnson et al 1999, Natta et al 2002, Dimobe et al 2018, Silva et al 2008).…”