Risk-Adaptive Conservation Zones: An Ecological Approach to Integrating Degradation Vulnerability into Spatially Explicit Carbon Crediting

Fragmentation and edge exposure have caused major, spatially structured carbon losses in once-intact forests globally, yet most carbon methodologies, though central to conservation finance, still rely primarily on projected deforestation and fail to explicitly capture degradation-driven losses spatially. Here, we develop a Risk-Adaptive Conservation Zone (RACZ) model that integrates landscape ecology, spatial gradients of deforestation, and mechanistic edge-effect dynamics to delineate evidence-based carbon crediting zones. Using the distance to the nearest deforestation as a proxy for spatial risk, and incorporating pressure intensity and landscape structure, the model generates a dynamic, project-specific RACZ that adapts to both external pressure and internal resistance. Two tropical areas (~ 350,000 ha) with contrasting deforestation pressure were tested. The model yielded a small RACZ of 1,150 ha (0.3%) in the intact, low-pressure landscape, concentrated in narrow bands near isolated edges. While for the highly fragmented frontier, RACZ expanded to 337,985 ha, covering 99.4% of the project area and reflecting pervasive, far-reaching degradation risk. These results show that RACZ restricts crediting to genuinely vulnerable areas in intact regions while capturing extensive risk in heavily fragmented frontiers. Therefore, this ecologically grounded approach complements core principles of the Integrity Council for the Voluntary Carbon Market (ICVCM) by improving environmental integrity and credibility in carbon accounting through aligning credit zones with spatial degradation risk.