Bridging the Scale Gap in Dryland Carbon Accounting: A Multi- Scalar Hybrid Methodology and the Composite Ecosystem Stability Index (CESI) for the Sudan Savanna

Abdulrahman Aminu; Muhammed Mustapha; Muhammad Abubakar Gusau; Musa; Muhammad Anka; Al-Mustapha Faisal

doi:10.56201/ijemt.vol.12.no10.2026.pg38.44

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Bridging the Scale Gap in Dryland Carbon Accounting: A Multi- Scalar Hybrid Methodology and the Composite Ecosystem Stability Index (CESI) for the Sudan Savanna

Abdulrahman Aminu, Muhammed Mustapha, Muhammad Abubakar Gusau, Musa, Muhammad Anka, Al-Mustapha Faisal

Abstract

Accurate carbon accounting in data-sparse dryland ecosystems is hampered by methodological silos: field studies are too localized, remote sensing lacks ground validation, and spatial models often rely on uncalibrated global defaults. This study presents a novel multi-scalar hybrid methodology that integrates field biophysics, multi-temporal remote sensing, and the InVEST ecosystem service model to assess carbon dynamics in the Sudan Savanna of Kebbi State, Nigeria. A two-phase design was employed: Phase 1 established a high-resolution biophysical baseline across 160 stratified field plots in four institutional landscapes; Phase 2 upscaled these findings using Landsat and Sentinel-2 imagery and a field-calibrated InVEST model. To synthesize the ecological health of the landscape, we developed a novel Composite Ecosystem Stability Index , integrating species richness, Shannon diversity, Pielou's evenness, and Total Carbon Stock. The field data revealed a mean carbon stock of 38.76 tC/ha, with significant variation across land-use types (Green Areas: 60.36 tC/ha; Bareland: 19.54 tC/ha). A critical methodological challenge was identified: field-measured soil organic carbon (1.9–5.87 tC/ha to 30 cm) was an order of magnitude lower than IPCC Tier 2 values used for landscape modeling (25–95 tC/ha to 100 cm), highlighting the limitations of using global defaults and shallow sampling depths. The CESI proved to be a robust diagnostic tool, revealing that carbon- rich monocultures (dominated by Azadirachta indica) can exhibit lower ecological stability than more diverse, mixed-use systems. This integrated framework provides a replicable, field- validated protocol for sub-national carbon accounting in drylands, offering a critical bridge between localized field ecology and macro-scale policy modeling.

Keywords

Multi-scalar methodology; Field biophysics; Remote sensing; Composite Ecosystem Stability Index

References

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Bridging the Scale Gap in Dryland Carbon Accounting: A Multi- Scalar Hybrid Methodology and the Composite Ecosystem Stability Index (CESI) for the Sudan Savanna

Abstract

Keywords

References

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