Land management for carbon sequestration
Lands with organic and wet soils are crucial for maintaining the planet’s carbon balance, as they store a significant amount of organic carbon. However, human activities such as drainage, agriculture, forestry, peat extraction, and aquaculture can disrupt this delicate balance, leading to increased greenhouse gas emissions, including carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). The oxidation of soil organic matter is one of the direct effects that can contribute to higher carbon and nitrogen emissions.
The management of lands with organic and wet soils plays a central role in addressing climate change. The 2006 IPCC (Intergovernmental Panel On Climate Change) guidelines establish that managed lands should be considered a proxy, or indicator, for anthropogenic emissions and removals. These guidelines are further detailed in the Wetlands Supplement, which provides updated methodologies for estimating emissions and removals from organic soils that have been drained for various purposes such as, agriculture, forestry, or aquaculture, and subsequently restored through refilling or re-saturation practices (e.g., peatland restoration).
Managing emissions in wetlands: approaches and methodologies for organic and coastal Soils
Chapter 3 of the Wetlands Supplement provides detailed guidance for assessing greenhouse gas emissions (CO₂, CH₄, N₂O) from restored organic wet soils, distinguishing by climate region and offering higher-tier methodologies. Particular attention is given to wetland restoration, which often includes the process of re-saturation (restoring water saturation levels in soils) to reduce greenhouse gas emissions or promote nature conservation. In general, reforestation or the restoration of degraded vegetation through refilling are interventions that help reduce oxidation and emissions.
For coastal wetlands, such as mangroves and seagrass meadows, brackish water management and drainage have a direct impact on greenhouse gas emissions and removals. Chapter 4 of the Wetlands Supplement provides guidance on estimating these impacts, considering activities such as aquaculture, salt production, and mangrove management. These activities can lead to land-use changes but, when properly managed, can help reduce emissions.
For inland wetlands with mineral soils, Chapter 5 introduces new methodologies for estimating greenhouse gas emissions and removals from drained and restored soils, as well as from human-made wetlands created for conservation purposes. In these areas, using updated methods to calculate changes in soil carbon stocks and applying revised methane (CH₄) emission factors are essential for ensuring effective management in line with IPCC guidelines.
Sustainable wetland management not only helps protect biodiversity but also plays a crucial role in climate change mitigation by reducing greenhouse gas emissions and improving soil carbon quality. With ongoing updates to methodologies and guidelines, such as those in the Wetlands Supplement, management practices can be optimised to support conservation efforts and minimise the impact of human activities on organic and wet soils.
Extensive valliculture in valle bertuzzi as an example of sustainable wetland management
Extensive valliculture, practised in areas such as Valle Bertuzzi, is a form of aquaculture that enhances the interaction between human activities and natural ecosystems. This approach is based on fish farming in lagoon basins maintained in balance through sustainable water management, without the use of advanced technologies, artificial feed, or fertilisers.
Human interventions are limited to essential operations, such as fish harvesting and the regulation of water flows via sluice systems and canals. Productivity relies entirely on the natural environment: aquatic vegetation, soil nutrients, and water quality create ideal conditions for the growth of euryhaline species, such as mullets and eels, which follow migratory cycles regulated by the hydraulic dynamics of the lagoons.
This model not only preserves biodiversity and the ecological functions of wetlands but also contributes to carbon regulation within ecosystems. The biomass of algae, vegetation, and organic matter in sediments acts as a significant CO₂ reservoir, mitigating climate-altering emissions. However, biological processes in these areas, such as anaerobic decomposition, can generate greenhouse gases like methane (CH₄), necessitating constant monitoring to maintain balance.
Moreover, the deterioration of water quality and the loss of original hydraulic connections, as observed in Valle Cantone, can compromise the entire ecosystem. Environmental restoration projects aimed at reactivating water flows and restoring wetland functionality are essential for re-establishing optimal environmental conditions while promoting conservation and sustainability.
With its low management costs and minimal environmental impact, extensive valliculture stands as a virtuous model for integrating economic needs with environmental protection, demonstrating how the rational use of natural resources can generate benefits for both humans and ecosystems.