Responses of carbon sequestration service for landscape dynamics in the Kaffa biosphere reserve, southwest Ethiopia

Abstract

Natural forests are fundamental ecosystems, helping to reduce atmospheric carbon dioxide concentration through carbon sequestration. Kaffa biosphere reserve is part of the Eastern Afromontane biodiversity hotspot as a forested ecosystem with a significant level of endemism and species richness. In the biosphere reserve, there was no adequate investigation because the spatial and temporal distribution, quantification, and economic valuation of the carbon balance of the biosphere reserve are poorly known. Therefore, the main objective of this study was to map and estimate the total carbon storage and sequestration of the biosphere reserve across space and time. Using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) and CA_Markov models, the study estimated the spatiotemporal variation of carbon stocks from 1986 to 2019 and made predictions for the years 2034 and 2049. Field data were collected from 155 plots of rectangular shape and species names, as well as their diameter at breast height and heights, for this study. Carbon stock was estimated using a species-specific allometric equation and the soil organic carbon was examined in the laboratory following the Walkley Black method. Carbon storage has varied across land use and land cover (LULC) types. The LULC types that are rich in vegetation cover had a higher amount of carbon stock on a per hectare basis. The biosphere reserve stores 478.3–457.3 megatons of carbon from 1986 to 2019, in which 4.4% of the carbon stored in 1986 was emitted into the atmosphere. The amounts of carbon emitted into the atmosphere were about 0.33, 0.57, 0.46, and 0.21 megatons in 1986, 1999, 2009, and 2019, respectively. This shows that the biosphere reserve has the potential to release a significant amount of emitted carbon. Therefore, the findings can be an effective tool in the preparation of sustainable land-plans, making environmental policies, and biodiversity conservation.