by: Emily Romano | April 17, 2024
Mangroves are one of the ecosystems ClimeCo is focused on this Earth Day. Our commitment to restoring these carbon sequestration powerhouses is one of the reasons we’ve been so excited to expand into Southeast Asia, a region containing more than 30% of the world’s mangrove ecosystems. As our current YAKOPI Project work in Indonesia continues to grow and succeed [1] [2] [3], we’ve been building additional mangrove-focused partnerships in Southeast Asia and look forward to sharing more details soon.
Considering our work and interest in this region, we’ve closely followed the Indonesian government’s development of the domestic National Registry System (SRN) and the international carbon market in Southeast Asia [4]. These markets have immense power to channel international finance into high-integrity nature-based solutions. Although details and timelines haven’t been finalized, we’re eager to leverage our expertise and participate wherever possible. We’ll follow up with additional coverage as the rules governing these markets solidify.
In the meantime, ClimeCo’s Brad Seely, Vice President for Nature-Based Solutions, Anna Stablum, Business Development Director, and I recently visited several of the YAKOPI Project field sites in North Sumatra, Indonesia. We were thrilled to see the planted sites and community-run nurseries in person and learned so much from our project partners.
To build on our past blog coverage of the importance of blue carbon [5] [6] [7] [8], we’ll provide additional background context on mangrove ecosystems and restoration, including a few insights from our Indonesia visit.
Mangrove Ecosystems
Mangroves are flowering trees and shrubs that grow in the brackish or saline intertidal zones of tropical and subtropical coastlines, of which there are more than 80 species. Mangrove roots require alternating periods of wet and dry, which determines their elevation above mean sea level (Figure 1). After pollination, seeds germinate into long, skinny pods called propagules, which drop into the water and float (sometimes for more than a year) until they are deposited somewhere they can take root. Approximately 147,000 km2 of mangroves exist today across tropical and subtropical regions [9], storing between 1000-2700 metric tons of carbon per hectare. This range is 3-5 times the amount of carbon stored by terrestrial forests [10].
Mangroves provide long-term benefits both for climate change mitigation and adaptation [12]. Beyond carbon sequestration, their thick, branching root networks trap sediment and prevent coastal erosion, which stabilizes shorelines. They act as a buffer, protecting coastal communities from wave energy and storm surge, preventing salt-water intrusion inland [13]. Their biofiltration capacity also improves runoff water quality by trapping pollutants and eroded sediment, which would otherwise negatively impact near-shore coral reef communities.
Despite the looming challenges posed by climate change, mangroves demonstrate resilience to harsh and dynamic environmental conditions. It is true that mangroves will undoubtedly suffer increased damage in regions with more extreme storm events, and there will likely be species whose ranges decline while others expand. However, they are relatively tolerant of acute and chronic stresses, such as changes to salinity and hydrologic conditions, they can self-establish in nutrient-poor substrates, and are thought to be capable of keeping pace with projected sea level rise, given adequate sediment supply. [14]
Mangrove ecosystems provide important support for marine food chains by exporting organic matter and serving as a habitat for thousands of species. These include commercially and locally significant fish, octopi, crabs, clams, and shrimp populations. Mangroves also produce edible and medicinal fruits, leaves, and syrups. These resources are essential for local communities, particularly in remote areas with scarce alternative economic opportunities. Some communities have developed silvofishery systems, which integrate aquaculture more sustainably with healthy mangroves or community-run ecotourism operations to attract revenue from intact mangroves.
Losses and Restoration Efforts
Unfortunately, 20-35% of mangroves have been destroyed globally over the past half-century, largely due to the installation of short-lived shrimp and fish aquaculture ponds. These often become unproductive after only a few years and are abandoned for newly cleared areas [15]. While drivers of loss differ by country and region, in Southeast Asia, mangrove loss is primarily due to harvesting commodities such as wood, charcoal, rice, or palm oil production [16] [17] (Figure 2). Indonesia has more mangroves than any other country, yet is experiencing among the highest rate (40%) of mangrove clearing. Rates are even higher in the Indonesian region of North Sumatra (60%), mainly due to aquaculture and damage from the December 2004 tsunami.
Only 22% of mangroves in Southeast Asia are formally protected [18]. For those that are cleared or damaged, natural regeneration is slow and often limited by ongoing disturbance or a lack of local mature forests to supply propagules [19] [20]. Restoration efforts are therefore necessary but require financial commitment and local ecological knowledge.
Numerous mangrove restoration projects worldwide have struggled or failed due to inadequate site design or consideration of the needs of local communities. Projects must include the following considerations to be successful [21]:
- Site selection should target areas where mangroves grew naturally in the past [22].
- Species chosen for planting should include a mixture of the species naturally living near the area to be restored.
- Seedlings should be planted in appropriate landscape positions, considering factors such as tidal range and duration, substrate characteristics, freshwater inputs, wave energy, and resistance to local pests.
- Stakeholder engagement should begin before project initiation and include landowners, community groups, and multiple levels of government to ensure that the project will protect land-tenure rights, not take place on disputed lands, and obtain the correct permissions to plant.
- Project governance should be designed to encourage indigenous and local (IPLC) groups to engage and participate in the project meaningfully.
- Finances or benefits derived from the project should be distributed equitably and empower vulnerable or marginalized groups.
- Project developers should understand local land use and causes of deforestation to ensure those pressures are removed from the project area and to protect any remaining natural mangroves.
- Contracts should be translated and explained in local languages so locals can clearly understand them. Feedback and grievance redress mechanisms should be developed for all projects using platforms that are locally appropriate and accessible.
- Projects should solicit and incorporate IPLC knowledge into project design. These groups often fill gaps in scientific lab and field-based science with local ecological knowledge. They may supply solutions to challenges or design adjustments that will maximize benefit generation and distribution for their communities.
ClimeCo’s approach to nature-based projects incorporates all these elements. We collaborate closely with reputable implementing partners to ensure comprehensive restoration of ecosystems. Our partners in Indonesia, YAKOPI, and PUR, possess extensive local ecological knowledge and work with communities to select appropriate species for planting, establish conditions conducive to survival, and safeguard the project. We are grateful for their extensive engagement with local communities and their clear commitment to improving food security and creating gender-equitable employment opportunities in remote villages.
Looking Forward
Our team has been amazed by the work achieved on the ground by our implementation partner, YAKOPI, whose work we initially sought to support in 2022 and who welcomed us warmly in December 2023. We also profoundly thank our project development partner, PUR, for their project management assistance and valuable guidance.
We were so thankful to meet community members in person during our visit, and to hear their enthusiasm for the project first-hand. We look forward to our continued partnership and to navigating the complexities of ecosystem restoration together.
Read the past blogs of the Blue Carbon Series – Blue Carbon 101 | Blue Carbon 102
[1] ClimeCo – ClimeCo Partners with YAKOPI and PUR Projet for Mangrove Reforestation Project in Indonesia
[2] Sustainable Brands – High-Quality, Nature-Based Solutions in Indonesia
[3] ClimeCo – Restoring Lost Mangroves and Livelihoods
[4] Carbon Pulse – Indonesia Business Council publishes wish-list for country’s carbon market
[5] ClimeCo – Blue Carbon 101
[6] ClimeCo – Blue Carbon 102
[7] ClimeCo – Emerging Efforts to Address Reforestation’s Most Challenging Problem
[8] ClimeCo – ClimeCo Projects Benefit Communities Around The Globe
[9] Global Mangrove Alliance – The State of the World’s Mangroves 2022
[10] World Resources Institute – Forest Carbon Stocks
[11] Zoological Society of London – Mangrove Rehabilitation and Conservation
[12] Nature – The vulnerability of Indo-Pacific mangrove forests to sea-level rise
[13] IOP Science – Sustainable forest management through natural mangrove regeneration
[14] Springer – Responses of Mangrove Ecosystems to Climate Change in the Anthropocene
[15] NASA – Mapping the Roots of Mangrove Loss
[16] Nature – Mangrove canopy height globally related to precipitation, temperature and cyclone frequency
[17] Wiley – Global declines in human-driven mangrove loss
[18] Global Mangrove Alliance – The State of the World’s Mangroves 2022
[19] IOP Science – Sustainable forest management through natural mangrove regeneration
[20] Science Direct – Restoration versus natural regeneration in a neotropical mangrove
[21] Global Mangrove Alliance – Best practice guidelines for mangrove restoration
[22] Nature – Mangrove reforestation provides greater blue carbon benefit than afforestation
About the Author
Emily Romano is ClimeCo’s Senior Project Manager of Nature-Based Solutions. Her work focuses on terrestrial reforestation, coastal and mangrove restoration, and improved forest management projects emphasizing social and biodiversity benefits.
