Land use change-driven greenhouse gas emissions in the Eastern Afromontane Rainforest Biodiversity Hotspot: evidence from the Yayu Coffee Forest Biosphere Reserve

The Eastern Afromontane biodiversity hotspot is renowned for distinctive and diverse biodiversity resources, contributing to conservation of species of global significance and mitigation of climate change. Nevertheless, the biodiversity conservation and climate change mitigation potential of this hotspot is declining over time due to unprecedented land use/land cover (LULC) changes. This study aims to quantify greenhouse gas (GHG) emissions associated with LULC changes from 2002 – 2023, considering Yayu Coffee Forest Biosphere Reserve (YCFBR) as a case study. The study utilized a multi-temporal, high-resolution satellite imagery from Landsat satellites for the years 2002, 2012, and 2023. LULC change classification was carried out following Intergovernmental Panel for Climate Change (IPCC) scheme, and changes were evaluated by integrating satellite images with field data. The default GHG emission factors specific to the area's land management systems, vegetation, and climate were acquired from the IPCC's National GHG Inventories guideline. The results indicated that 4,419.95 km 2 and 1,827.59 km 2 of total land conversion were observed between 2002 and 2012, and 2012 and 2023, respectively. The findings further revealed biomass combustion in different converted land uses in the YCFBR contributed 31117 and 13884 tonnes of CO 2 emissions annually in 2012 and 2023, respectively. Between 2012 and 2023, the carbon sequestration potential of forest and coffee plantation in the region was substantially declined by 84% and 79%, and 27% and 98%, respectively. Forests and coffee plantations were identified as the major contributors to GHG storage, while crop cultivation was found to be a considerable source of emissions. The study suggested a continuous decline in YCFBR's GHG sequestration potential and capacity to combat climate change as Afromontane biodiversity hotspot, regardless of land use conversion history. Thus, effective ecological restoration is critical to reverse the decline and enhance the YCFBR's ecological integrity.