Ancient Custom, Carbon Cash: A New Blueprint for Saving Indonesia’s Mangroves

On the coast of East Seram Regency in Indonesia’s Maluku archipelago, a governance experiment is underway that could reshape how tropical nations pay for climate protection. A research team led by Sadali IE of Pattimura University has built and tested an adaptive mangrove governance model that weaves together three strands rarely found in the same policy fabric: a centuries-old customary harvest prohibition known as Sasi, the modern economic valuation of blue carbon, and a fiscal instrument called Ecological Fiscal Transfer that channels government money to communities based on ecological performance. The study, published in Environmental Management, offers one of the most detailed attempts yet to fuse indigenous institutions with market-based climate finance in a single, workable framework.

The stakes could hardly be higher. Mangroves are among the most carbon-dense forests on Earth, storing vast quantities of carbon in waterlogged soils that can persist for millennia. When these forests are cleared or degraded, that carbon escapes as carbon dioxide, and the coastline loses a natural buffer against storms and erosion. Indonesia holds the world’s largest mangrove estate, making its forests a linchpin of both national climate commitments under the Paris Agreement and global blue carbon strategies. Yet mangroves across Southeast Asia continue to be converted for aquaculture, agriculture, and coastal development, driven by pressures that conventional top-down regulation has struggled to contain.

The researchers framed their investigation within a Social-Ecological Systems approach, an analytical tradition associated with scholars such as Elinor Ostrom that treats ecosystems and human institutions as an inseparable whole. Rather than asking only how much carbon the mangroves store, the team asked who governs them, what pressures drive their change, and what incentives could align community behavior with conservation. To answer these questions, they deployed a mixed-methods design combining biophysical field measurement, socio-institutional surveys, carbon economic valuation, and a Driver-Pressure-State-Impact-Response, or DPSIR, analysis.

The biophysical results reveal a forest under strain but still enormously valuable. Although mangrove extent in the study area has declined, the remaining stands retain substantial carbon stocks. By comparing carbon stocks across multiple time points, the team estimated an annualized carbon-stock change of 10,496.29 metric tons of CO2 equivalent per year, equivalent to roughly 2.98 tons of CO2 equivalent per hectare per year. That figure represents both a warning and an opportunity: it quantifies the emissions risk if degradation continues, and it defines the volume of avoided emissions that could be monetized if the forest is protected.

Translating carbon into money is where the model becomes genuinely novel. Using voluntary carbon market prices, the researchers calculated a potential Carbon Economic Value of between IDR 839.7 million and IDR 1.68 billion per year for the regency’s mangroves. In a region where local government budgets are thin and livelihoods depend heavily on coastal resources, that stream of revenue could fund restoration, monitoring, and community development. Crucially, the study links this valuation to Indonesia’s recent regulatory architecture, including the 2022 law on central-regional financial relations and a 2025 presidential regulation on carbon economic value instruments, suggesting the model is not a theoretical exercise but something that could be implemented under existing law.

The second pillar of the model is Sasi, the customary system of periodic harvest closures and resource restrictions practiced across Maluku for generations. Under Sasi, community leaders and customary institutions declare certain areas, species, or seasons off-limits, enforced through social sanction and ritual rather than police power. The study’s socio-institutional analysis found striking support for this approach: 91.7 percent of respondents favored integrating Sasi into formal mangrove governance. That level of consensus matters because conservation interventions imposed without local legitimacy frequently fail, while rules rooted in shared norms tend to be self-enforcing and resilient over decades, as earlier research on Sasi’s institutional endurance in Central Maluku has documented.

The third pillar addresses a chronic weakness of community-based conservation: money. Ecological Fiscal Transfers are budget allocations from higher levels of government to local governments, or from local governments to villages, weighted by ecological indicators such as forest area or protected status. The concept, already piloted in parts of Indonesia and elsewhere in Southeast Asia, rewards jurisdictions for keeping ecosystems intact. In the proposed model, performance-based fiscal incentives would flow to communities and villages that maintain mangrove cover and carbon stocks, creating a recurring financial reason to uphold Sasi closures and resist conversion pressure. The researchers identified these incentives, alongside restoration programs, marine protected areas, and community participation, as the most promising management responses emerging from their DPSIR analysis.

That DPSIR framework also clarified the threats. Land-use change, resource utilization, and coastal development emerged as the principal pressures associated with mangrove change in East Seram. This pattern mirrors regional trends documented across Southeast Asia, where mangrove deforestation between 2000 and 2012 was driven largely by aquaculture expansion and plantation agriculture. By mapping the causal chain from drivers to pressures to impacts, the study gives policymakers a diagnostic tool: each pressure can be matched to a specific response, whether a fiscal incentive, a customary closure, or a protected area designation, rather than a one-size-fits-all decree.

What makes the model adaptive, in the authors’ framing, is that the three components feed back into one another. Carbon valuation generates revenue; fiscal transfers distribute that revenue to the communities whose customary institutions actually enforce protection; and Sasi provides the social legitimacy and low-cost enforcement that neither markets nor bureaucracies can supply alone. Monitoring of carbon stocks then becomes a performance metric that recalibrates the fiscal flows, allowing the system to adjust as conditions change. This loop echoes the principles of adaptive co-management developed in the resilience literature, in which knowledge generation, bridging organizations, and social learning allow governance to evolve alongside the ecosystem it manages.

The implications extend well beyond a single regency. Indonesia’s Nationally Determined Contributions rely heavily on land-based and coastal emission reductions, and mangrove protection is among the cheapest and most effective natural climate solutions available. The authors argue that their evidence-based framework could be replicated in other tropical coastal regions with similar social-ecological conditions, particularly where customary tenure and local institutions remain strong. For the global blue carbon community, the East Seram case demonstrates something increasingly recognized but rarely operationalized: that carbon markets and fiscal policy succeed only when they are anchored in the institutions communities already trust. If the model moves from paper to practice, the ancient rhythm of Sasi closures could become, quite literally, a line item in the climate ledger.

Subject of Research: Adaptive mangrove governance integrating customary Sasi institutions, blue carbon valuation, and ecological fiscal transfers in East Seram Regency, Indonesia

Article Title: An Adaptive Mangrove Governance Model Integrating Sasi, Carbon Economic Valuation, and Ecological Fiscal Transfer for Mangrove Management in Maluku, Indonesia: Evidence from East Seram Regency

Article References: IE, S., Retraubun, A. S. W., Tetelepta, J. M. S., Tupan, C. I., & Rahman, R. (2026). An Adaptive Mangrove Governance Model Integrating Sasi, Carbon Economic Valuation, and Ecological Fiscal Transfer for Mangrove Management in Maluku, Indonesia: Evidence from East Seram Regency. Environmental Management, 76(10), Article 327. https://doi.org/10.1007/s00267-026-02630-x

Image Credits: AI Generated

DOI: 10.1007/s00267-026-02630-x

Keywords: mangroves, blue carbon, Sasi, adaptive governance, ecological fiscal transfer, carbon economic value, Indonesia, Maluku, climate mitigation, social-ecological systems, DPSIR, coastal management