May 19, 2017 by Species Ecology
Ecological Mangrove Restoration (EMR): Re-establishing a more biodiverse and resilient coastal ecosystem with community participation
Importance of Mangroves and Need for Restoration
Mangrove forests are vital for healthy coastal ecosystems in many regions of the world. They support an immense variety of sea life, and are prime nesting and feeding sites for hundreds of migratory bird species. Healthy mangrove forests play an important role in carbon sequestration—their ecosystems and corresponding wetlands account for nearly a third of the world’s terrestrial carbon stores and sequester more carbon per hectare than tropical rainforest (Ramsar Secretariat 2002). Mangroves also form a natural coastline protection shield against floods, storms or other natural disasters such as hurricanes and tsunamis. Healthy mangrove forests purify water flowing through them to the sea, and form a natural coastline protection shield against floods, storms or other natural disasters such as hurricanes and tsunamis. Beyond these irreplaceable ecosystem services, mangroves provide important socio-economic benefits to coastal communities. In regions where the forest has been destroyed, local coastal communities face serious problems of diminished wild fisheries and threatened traditional livelihoods.
In spite of those important functions, more than 50% of the global mangrove forests have been destroyed over the last 100 years, mainly caused by human development (FAO, 2008). According to the FAO’s statistics, mangroves are being lost now at the rate of around 1% per year. That means nearly 150,000 ha of mangroves are still being lost each year (FAO 2008). In addition, mangrove ecosystems and salt marshes are vulnerable to negative effects caused by climate change such as rising sea levels, higher temperatures and natural disasters. Reforestation programs where the mangroves have been lost would therefore rebuild mangrove forest protection and restore the potential for sustainable development. The improvement of mangrove ecosystems will enhance their function as a natural water
treatment system and spawning grounds for fish, improving health and livelihood possibilities thus benefiting marginalized local communities, and the vital carbon sequestration powers of mangroves would be restored.
However, there are relatively few examples of successful, long-term mangrove rehabilitation, partly because most attempts have not corrected the problem(s) which caused the mangrove loss in the first place. Moreover, the great majority of mangrove restoration attempts are merely hand planting of a single species- Rhizophora, or red mangrove -forming monoculture plantations rather than truly restoring vibrant and biodiverse multi-species mangrove wetlands. Many plantings are not restoration, but rather attempts of ecosystem conversion of natural mudflats to mangroves.
In search of a compromise between assigned economic worth and biodiversity, Mangrove Action Project (MAP) promotes the concept and practice of Community-based Ecological Mangrove Restoration (CBEMR). This holistic approach to mangrove restoration views the proposed plant and animal communities to be restored as part of a larger ecosystem, connected with other ecological communities that also have functions to be protected or restored. Mangrove forests can self-repair, or successfully undergo secondary succession, if the normal tidal hydrology is restored and if there is a ready source of mangrove seedlings or propagules from nearby stands that are accessible to reseed an area. CBEMR focuses on re-establishing the hydrology which will facilitate this natural regeneration process. CBEMR also engages local communities in the restoration process, empowering them to be stewards of their environment, and enabling them to regain the livelihoods destroyed when the mangroves were destroyed. Three-day intensive workshops train local people to do CBEMR, and community management plans ensure project sustainability.
Working with local communities and NGOs, MAP has been piloting small successful CBEMR projects in Thailand, Indonesia, and El Salvador. However, many challenges remain, such as the need for more a robust monitoring and evaluation model with internationally recognized outcome indicators; issues of land tenancy and site availability; restrictions imposed by funders; carbon offset plantings encouraging ecosystem conversion rather than true mangrove restoration; and securing government permits and approvals. MAP plans to continue its CBEMR work with new projects in SE Asia and Latin America, gradually brought to greater scale, and in the process learn to overcome current challenges and further refine the CBEMR model.
Failure of usual mangrove restoration methods
However, very few organizations so far have dealt effectively with mangrove restoration and relatively few examples exist of successful, long-term mangrove rehabilitation, partly because most restoration attempts have not corrected the problem(s) causing the mangrove loss in the first place. The great majority of mangrove restoration attempts are merely hand planting of a single species- usually the Rhizophora, or red mangrove -forming monoculture plantations rather than truly restoring a vibrant and biodiverse mangrove wetland. These attempts have largely failed, either leaving dead seedlings and much disappointment in their wake, or establishing mangrove plantations or monocultures with very limited potential in biodiversity.
This practice of hand planting propagules and seedlings is aptly described by EMR pioneer Dr. Robin Lewis as “the gardening method,” whereby monoculture plantations of usually one or two varieties of mangrove are established (Lewis, 2009). These plantations are less resilient to natural disasters, diseases or insect infestations. In tropical areas where there may be two or more dozen mangrove species, it makes little sense to label this “gardening” approach as “restoration” because the natural biodiversity and productivity of the original healthy mangrove forest is not an outcome produced under this simplified technique. Most often, these “gardening” efforts fail to establish any significant lasting mangrove cover.
Following the December 2004 tsunami, there was an urgent, but ill-conceived, reaction to establish protective mangrove greenbelts. A wide call was issued and supported by many governments, inter-governmental agencies, and NGOs. The majority of these rather hastily planned mangrove “restoration” attempts failed because of badly chosen siting or wrongly selected species for the plantings. Many red mangrove seedlings or propagules were hand-planted in disturbed former mangrove sites, as well as mud flats and salt flats. However, few of these survived because the necessary conditions for seedling survival were not clearly evaluated in advance.
The failures were due to many factors: poor site selection, lack of understanding mangrove ecology and hydrology, short project period and desire for quick results from donors, lack of community consultation and participation, relief agencies with no previous experience with mangroves, lack of follow-up and monitoring, and planting mainly Rhizophora sp. Seedlings and propagules regardless if this was appropriate for the selected site or not- too often planting the wrong species in the wrong place at the wrong time. One reason for this monoculture approach is that the specific species planted can produce desirable wood products that can be sold on local markets and therefore improves the livelihood of the people living in the surrounding communities. However, these plantations are often established in mud flats, salt flats and even sea grass beds, thus attempting to convert one viable and important ecosystem into another. This is not a wise solution when attempting to “restore” ecosystem functions, even if these projects do successfully establish some mangroves. Most often, these “gardening” efforts fail to establish any significant mangrove cover.
The CBEMR Alternative
In search of a compromise between economic value and biodiversity, Mangrove Action Project (MAP) promotes the concept and practice of Community-based Ecological Mangrove Restoration (CBEMR). CBEMR is based upon a set of basic ecological principles and is capable of restoring a much more naturally functional and biodiverse mangrove ecosystem when compared to other more capital and labor intensive methods such as monoculture hand-planting (Lewis 2009).
MAP saw the opportunity and need to introduce the EMR methodology first developed by Dr. Robin Lewis in the US into Asia to improve the success of mangrove restoration. The challenge was to adopt and introduce EMR which was only described previously in scientific journals, to the socio-economic and cultural situation of mangrove communities, NGOs and governments of developing countries in Asia. In the process, MAP has developed a sustainable model that engages and integrates the local communities, and which we are calling Community-based Ecological Mangrove Restoration (CBEMR).
To ensure success, long term monitoring and evaluation must be built into any restoration framework. Too often, little follow-up in monitoring and evaluation occurs, and thus little is gained in terms of lessons that could be learned from past mistakes or successes. Success is often judged by percent of surviving seedlings at often 3-6 months and sometimes one or two years after the attempt at restoration, but we need at least five years to better understand the nuances that determine success or failure at each unique restoration site. And we need to better define exactly what constitutes the outcome indicators we look for in determining that success. Is it restored biodiversity, forest density and height, or other factors we are looking for?
According to Robin Lewis, determination of success is likely time specific. He suggests preparing a “time zero,” or baseline, report by setting up test quadrants to compare statistically with similar size quadrants within the control areas (from personal correspondence). According to Dr. Norm Duke of Mangrove Watch, for tidal wetlands, “…there has been no suitable assessment methodology that managers can readily use. So these valuable wetland ecosystems have largely been neglected by managing agencies and monitoring programs – a factor that arguably may have contributed to some declines” (Mangrove Watch; Baird and Quarto 1994).
MAP is currently engaged in a CBEMR project on the Andaman coast of Thailand and is actively seeking both project partners and funders for new CBEMR projects in such locations as the Gulf of Fonseca (El Salvador, Honduras, and Nicaragua); the Choco Coast of Colombia; the Sundarbans of India; Lake Maracaibo in Venezuela, and additional sites in Thailand. The sites will be strategically selected in order to:
1) Further perfect the CBEMR methodology
2) Systematize the resolution of the challenges presented above
3) Demonstrate CBEMR feasibility on a larger scale
4) Explore the integration of CBEMR into national and international eco-initiatives, such as national coastal ecosystem plans, carbon off-sets, payments for ecosystem services (PES), and REDD+.
To disseminate the knowledge on CBEMR and to allow its wider application in different countries, a series of CBEMR workshops are being implemented with the aim of teaching stakeholders from different backgrounds the CBEMR methods. Plans are to establish regional core groups of restoration practitioners trained in CBEMR. These core groups will share information and experiences on how best to implement EMR projects taking into consideration local conditions.
Baird, I., and A. Quarto, 1994 “The Environmental and Social Costs of Developing Coastal
Shrimp Aquaculture in Asia,” pp. 3-4 Earth Island Journal
FAO. Loss of mangroves alarming – FAO. 2008. http://www.fao.org/newsroom/en/
Lewis, RR. III. 2009. Methods and criteria for successful mangrove forest restoration.
Chapter 28., pages 787-800 in GME Perillo, E Wolanski, DR Cahoon, and MM Brinson
(eds.) Coastal Wetlands: An Integrated Ecosystem Approach. Elsevier Press.
Lewis, RR, B. Brown, A. Quarto, J. Enright, E. Corets, J. Primavera, T Ravishankar, O
Stanley and R Djamaluddin. 2006. Five steps to successful ecological restoration of
mangroves. Mangrove Action Project/Yayasan Akar Rumput Laut. Yogyakarta, Indonesia.
Ramsar Secretariat (2002): Climate change and wetlands: impacts, adaptation and
mitigation. COP8, Information Paper DOC 11. Ramsar Secretariat, Gland, Switzerland