Effects of diverse mangrove management practices on forest structure, carbon dynamics and sedimentation in North Sumatra, Indonesia

For decades, mangrove forests have been under tremendous pressure due to deforestation and conversion. To sustainably manage the mangroves that remain, an ecosystem approach to management is essential. Two different management regimes – conservation and restoration – were assessed, looking at their respective effects on forest structure and carbon cycling capacity, when compared with degraded mangrove. We found that mangrove restoration enhanced tree density, while mangrove conservation was able to maintain species diversity. In terms of carbon budgets, aboveground carbon was lower in restored mangrove (79.40 ± 37.41 Mg C ha−1) when compared with conserved mangrove (92.26 ± 22.65 Mg C ha−1), but was almost double that found in degraded mangrove (39.89 ± 27.49 Mg C ha−1). Although conserved mangrove had higher aboveground carbon, lower amounts of soil carbon were found in conserved mangrove (127.49 ± 33.21 Mg C ha−1) than in restored and degraded mangrove (236.26 ± 20.33 Mg C ha−1 and 139.17 ± 25.44 Mg C ha−1, respectively). The elevation change was highest in degraded mangrove (41.7 ± 24.0 mm yr−1), followed by restored (20.7 ± 14.6 mm yr−1) and conserved mangrove (12.2 ± 3.9 mm yr−1). Carbon burial in conserved mangrove (1.20 ± 1.90 Mg C ha−2 yr−1) was double that of degraded mangrove (0.63 ± 0.60 Mg C ha−2 yr−1). Ultimately, we conclude that although a conserved mangrove is not always the end result of mangrove restoration and sustainable management, finding balance between structural development and ecosystem function is essential to serve different objectives, including biodiversity maintenance

Managing Water Regimes: Controlling Greenhouse Gas Emissions and Fires in Indonesian Tropical Peat Swamp Forests

Until recently, tropical peat swamp forests in Indonesia have been subject to increasing pressure from land-use change and excessive drainage. This has increased greenhouse gas (GHG) emissions and risk of fires. Five tropical peat landscapes under different management regimes were selected and assessed with regards to GHG emissions and vulnerability to fire. Converted peat swamp forest emitted CO 2 at a similar rate to primary and secondary peat swamp forests. Total emissions ranged between 41 and 52 Mg CO 2 /ha/yr, and 85% of this was from heterotrophic respiration. Managing groundwater levels (GWL) is crucial to GHG mitigation actions. Peatland fire risk is closely associated with GWL, and fire risk can be reduced by 30% when peat rewetting is prioritized in the most vulnerable areas. Lack of coordinated water management could lead to uncontrollable GWLs, peat subsidence, and fires, causing large GHG emissions and other environmental degradation. Government-initiated Forest Management Units could manage peatlands at a regional level. Compliance mechanisms need to be institutionalized to control emissions, land subsidence, and fire incidence