Ecological Mangrove Restoration (EMR): Re-establishing a more biodiverse and resilient coastal ecosystem with community participation

Transcription

1 Ecological Mangrove Restoration (EMR): Re-establishing a more biodiverse and resilient coastal ecosystem with community participation Alfredo Quarto Executive Director, Mangrove Action Project, PO Box 1854, Port Angeles, WA , USA, mangroveap@olympus.net ABSTRACT: 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 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. And mangroves can sequester far more carbon per hectare than tropical rainforest. 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 by human development. Reforestation programs in these areas would therefore rebuild mangrove forest ecosystems and increase the potential for sustainable development.. 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 multispecies 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.

2 Key Words: Ecological Mangrove Restoration, EMR, Hydrology, Resilience, Biodiversity, Community-based, Mangrove Rehabilitation, 1. Introduction 1.1 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 marine life and are a refuge for juvenile fish, crabs, shrimp and mollusks and serve as nurseries for coastal fisheries. 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. Beyond these irreplaceable ecosystem services, mangroves also provide important socioeconomic benefits to coastal communities. In regions where the forest has been destroyed, local coastal communities are left with marginal or unproductive fisheries and loss of 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. 1.2 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

3 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. Fig 1. This mangrove plantation was cited as an example of how planting mangroves can also protect coastlines against storm surges and rising sea level yet clearly is an example of habitat conversion from mud/sand flat to mangrove forest and is not supported by MAP. Photogragh by: O. Jonsson 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 handplanted in disturbed former mangrove sites, as well as mud flats and salt flats. (see Fig.1) However, few of these survived because the necessary conditions for seedling survival were not clearly evaluated in advance (Samson and Rollon 2008; Dahdouh-Guebas 2006; Dahdouh-Guebas et.al. 2005). 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 (Lewis 2005; Lewis 2009; Samson and Rollon 2008; Dahdouh-Guebas et.al. 2005). 1.3 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).

4 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). This paper will describe CBEMR, its preliminary results to date, and the resulting challenges, opportunities and lessons learned. 2. Materials and Methods 2.1 Ecological Mangrove Restoration (EMR) Defined Ecological restoration has been defined as the process of repairing damage caused by humans to the diversity and dynamics of indigenous ecosystems (Jackson et.al. 2006). Ecological Mangrove Restoration (EMR) is a holistic approach to mangrove restoration that also includes a view of the proposed plant and animal community to be restored as part of a larger ecosystem with other ecological communities that also have functions to be protected or restored. EMR was developed by MAP s chief technical advisor, Robin Lewis who is a consultant based in Florida with over 30 years of mangrove restoration project implementation, mostly in Florida and Latin America. Lewis has used EMR very effectively to restore both the biodiversity of functionality of mangrove ecosystems (Lewis 2009). EMR aims at the restoration of certain ecosystem traits and the replication of natural functions. It has been shown that mangrove forests around the world can self-repair or successfully undergo secondary succession over periods of years if: 1) the normal tidal hydrology is not disrupted and 2) the availability of waterborne seeds or seedlings (propagules) of mangroves from adjacent stands is not disrupted or blocked (Lewis 1982, Cintron-Molero 1992). Because mangrove forests may recover without active restoration efforts, it has been recommended that restoration planning should first look at the potential existence of stresses such as blocked tidal inundation that might prevent secondary succession from occurring, and plan on removing those stresses before attempting restoration (Hamilton and Snedaker 1984; Cintron-Molero 1992). The second step is to determine by observation over 6 months to a year if natural seedling recruitment is occurring once the stress has been removed. There should be evidence of volunteer seedlings appearing on site within one year of the hydrological adjustments and if not, a reassessment of the hydrodrology and identification of other potential problems. If seed limitation is a factor, then buckets of collected seeds can be broadcast on an incoming Spring tide. Only if natural recovery is not occurring should the third step of considering assisting natural recovery through planting be considered. Unfortunately, many mangrove restoration projects move immediately into planting of mangroves without determining why natural recovery has not occurred. There may even have been a large capital investment in growing mangrove seedlings in a nursery before the stress factors are assessed. This often results in major failures of planting efforts. Instead, MAP supports the restoration of a naturally functioning habitat through the 6-step EMR approach to ecological mangrove restoration and not plantation forests with disregard for natural species composition. (Lewis 2005). 2.2 MAP Introduces CBEMR MAP is partnering with local communities and other NGOs to restore degraded and destroyed mangrove areas. MAP s CBEMR program works at restoring natural hydrology or

5 water flows, and thus greatly increases the overall success rate for regenerating large areas of degraded mangrove forests. This method has proven extremely successful in past endeavors by MAP s chief technical advisor, Robin Lewis- for example in West Lake, Florida, USA- and is being implemented by MAP via small-scale projects in Indonesia, Thailand and El Salvador. The method is also cost-effective and produces a more biodiverse restoration with excellent long-term results (Stevenson et.al. 1999). These small-scale projects are serving as working models, intended to inform and inspire larger-scale, more intensive applications of EMR where it is needed. If applied more broadly, MAP s CBEMR method could restore ecologically biodiverse and healthy mangrove ecosystems in an effective, long-term, and economical manner (Lewis 2005). MAP is especially interested in restoring some of Asia s estimated 250,000 ha of abandoned shrimp farms located in former coastal wetland areas (Estimate given by Robin Lewis via verbal communication). 2.3 Technical aspects of EMR- the Six Steps of EMR (Lewis et al 2006; Brown 2008) Before beginning the project, preliminary research needed. In selecting a specific site for mangrove restoration, things to note include tide tables and measured tidal levels. Also, one should look for available literature about the mangroves of the area describing their distribution and tidal requirements. Are there any recent or even historical relevant aerial photos? Have there been prior efforts to restore mangroves in the area, and if so, what were the results in terms of successes and failures? What were the lessons learned from these prior efforts? Step 1) Understand the Local Mangrove Ecology It is important to understand both the individual species and the community ecology of the naturally occurring mangrove species at the site, paying particular attention to patterns of reproduction, distribution, and successful seedling establishment. One must understand the autoecology (individual species ecology) of the mangrove species at the site, in particular the patterns of reproduction, propagule distribution, and successful seedling establishment. For example, mangroves often occur in zones, which are groupings of the same species of mangrove within a whole mangrove forest. Zonation occurs because different species of mangrove need particular conditions to grow. Some species require more water than others, while others may be more tolerant of salinity than others. Step 2) Understand the Normal Hydrology One must understand the normal hydrology that controls the distribution and successful establishment and growth of targeted mangrove species. Each mangrove species thrives at a different substrate level which in some part dictates the amount of exposure the mangrove will have to tidal waters. Thus, it is important to study tide charts for the area and take measurements in healthy mangroves relating to substrate height/depth to the various species of mangroves that exist at each depth. It is also vital to imitate the slope and topography (relative height) of the substrate from a nearby healthy mangrove forest. And, it is essential to note the critical periods of inundation and dryness that govern the health of the forest. Step 3) Assess the Modifications of the Mangrove Environment One must then assess the modifications of the mangrove environment that have occurred and that may prevent natural secondary succession. Any plans for mangrove restoration must first consider the potential existence of stresses such as blocked tidal inundation that might prevent secondary succession from occurring, and plan on removing that stress before attempting restoration. It is important to understand the past use of the area. First and foremost, was the area intended for restoration actually a mangrove area in the past?

6 Oftentimes, mangroves are planted in areas such as mud flats, salt marshes, or lagoons assuming that the area would be better off or more productive as a mangrove forest. This is ecosystem conversion, not restoration. Mud flats have their own ecological purposes, such as feeding grounds for migratory shorebirds. Prior to any attempt at planting mangroves or attempting another type of restoration it is imperative to determine if the area is presently suitable for mangrove growth. If not, what are the stresses preventing growth of mangroves? It is best to work with the local community to help determine how the mangrove area has changed over time and why. Factors that might be affecting mangrove regeneration may include the following: Lack of freshwater Blockage of tidal exchange Hyper-saline or acid sulfate soils (usually found after intensive shrimp farming) Overgrazing by livestock such as goats, cattle, camels etc. Shoreline abrasion and lowered substrate level Human or boat traffic at landing sites and over exploitation of trees for firewood Step 4) Selecting a Restoration Site Select appropriate restoration areas through application of Steps 1-3, above, that are both likely to succeed in rehabilitating a forest ecosystem and that are cost effective. Consider the available labor to carry out the projects, including adequate monitoring of their progress towards meeting quantitative goals established prior to restoration. This step includes resolving land ownership/use issues necessary for ensuring long-term access to and conservation of the site. Survey techniques used to select a suitable site employ topographic survey instruments such as an auto-level that help determine relative substrate elevation. An elevation survey can also be undertaken using simple tools as a water level; rubber tubing, water and meter sticks. One basic theory behind hydrological rehabilitation is to recreate a natural slope and substrate height which will support normal tidal flow, and the natural re-establishment and growth of mangrove seedlings. Dike walls of disused shrimp ponds need to be leveled, and ditches need to be filled. If one cannot level dike walls entirely, opening strategic breaches may be enough to support the exchange of tidal waters and should lead to further degradation of the dike walls over time. If financial resources for or access to heavy equipment are lacking, one may need to recruit community volunteers or employ community labor to get the job done. Step 5) Design the Restoration Program Next, one designs the restoration program at appropriate sites selected in Step 4, to restore the appropriate hydrology, including the original tidal streams, and utilize natural volunteer mangrove recruitment for natural plant establishment. Tidal streams run through mangrove areas from the terrestrial edge to the sea. They are narrower upstream, widening as they meander to the coast. Tidal streams are fed from the landward edge by ground water, springs, surface runoff and streams. Because they are connected to the sea, tidal streams facilitate the exchange of tidal waters in and out of the mangrove area, and are the routes for natural seedlings to enter and colonize an area. When tidal streams are disturbed, seedling recruitment may be blocked and the affected site s existing mangroves may dry out, and die over time. Determine by observation if natural seedling recruitment is occurring once the stress has been removed. This means monitoring. Are seedlings coming into the area and naturally

7 taking root? If so, what is the density of the natural plantings and what is the health and vitality of the seedlings? In the case of rehabilitating disused shrimp ponds, it may be enough to create strategic breaches in the dike walls. In this case, less rather than more cuts in dikes is better. The reason is that the tidal prism (the amount of water that can enter an opened pond between high and low tide) needs to be channeled to the maximum extent possible through a few key openings that are wider downstream than upstream. This mimics the normal operation of tidal streams in mangroves (see above). Fewer openings produce greater velocities as the flow is restricted, which in turn produces scouring, which keeps the human-made openings open and reduces the chances of siltation and closure. Creating too many openings will distribute the tidal prism over many points, reducing the velocity, and inducing less scour and more siltation. Even if mangroves survive for several years in your rehab area they may remain stunted or even die out unless hydrological conditions are truly supportive of mangrove growth. If seedlings have established in the rehabilitation area, but at lower densities than hoped for, you may consider planting. But planting costs can double the overall cost of a project and may limit the biodiversity of the site due to competition from planted mangroves. If no seedlings have established in the area, even though a natural seed source is nearby, you will have to re-evaluate the effectiveness of your hydrological rehabilitation. Perhaps there are still blockages to normal tidal flow or there is a disturbance in the seed source. Step 6 Planting Utilize actual planting of propagules or seedlings only after determining through Steps 1-5, above, that natural recruitment will not provide the quantity of successfully established seedlings, rate of stabilization, or rate of growth as required for project success. There are several good guides to effective mangrove planting, which one can find via a Google search. It is a good idea to do some small test plantings to ensure the conditions are appropriate for the desired species rather than mass plantings. Mangrove species can be tested in small dense plots at the correct strata height. Any natural occurring mangrove trees on site or volunteers will be an excellent reference for planting. As mangrove do not grow naturally in straight rows this should be avoided. There are four sources of seeds/propagules for mangrove planting; local seed sources 2.4 Community Engagement during incoming Spring tides. A critical piece that MAP has added to Robin Lewis EMR model is community engagement and empowerment, recognizing that sustainable mangrove restoration requires the full participation of the local affected people. For local populations, mangroves provide food, medicines, tannins, fuel wood, charcoal and construction materials. For millions of indigenous and local coastal residents, mangrove forests are vital for their everyday needs. Pisit Charnsnoh of Thailand s Yadfon Foundation called the mangroves the supermarkets of the coastal poor, offering dependable, basic livelihoods that sustain their traditional cultures, while supporting basic human needs (Warne 2007). MAP builds on these traditional community ties to the mangroves. To involve the communities from the start of the project, it is important to learn about the past and present condition of the proposed mangrove site and the relationship and utilization of the mangroves by the local community. Also, any past efforts at mangrove restoration

8 should be evaluated. The community will need to develop a management plan to deal with the cause(s) of mangrove destruction in the first place. The destruction could be due to overexploitation for fuel wood, illegal cutting and/or development encroachment, grazing by livestock or other conflicting uses. Often it will take time to develop and implement a workable solution while other times a viable strategy may not be found, which will prevent moving ahead with mangrove restoration plans. The CBEMR approach is introduced to local community members interested in acting as future monitors and resource managers at the sites selected. This presentation is meant to encourage the local community to get involved, which is one of our main points of interest to help build the capacity of local communities to better manage and conserve their natural resource base (Lewis et.al. 2006). Once the community is engaged, critical to the process is development of a community management plan by the local conservation group, which will be the primary force preventing the repeated degradation of the restoration site. Strong community stewardship ensures a central stakeholder role in future mangrove management decision-making processes. A program for monitoring and evaluation of restored sites by local community members is built into the CBEMR process with a 3-5 year plan to ensure success of the endeavor. Attaining community-based management or co-management status will greatly aid the long term protection of the restoration site; need to develop community ownership and stewardship for the project to succeed. Once the management plan is successfully being implemented, mangrove restoration can move forward in parallel (Lewis et. al. 2006). MAP offers three-day intensive CBEMR training workshops that instill the basic principles of EMR in those participating in the workshop and that incorporate hands-on fieldwork in actual restoration sites. Each workshop is geared towards the local conditions of the host country and region, involving local mangrove ecologists, local officials, local communities and their associate community-based, non-governmental organizations (NGOs) in the process. Once the community is trained, MAP offers guidance and technical support to ensure the restoration s success. 2.5 Overview: The Specific Overall Project Objectives of CBEMR The CBEMR objectives are: Restoration and sustainable management of mangrove forests by the target communities following the EMR approach at selected pilot sites. Protection and conservation of mangrove forests as carbon sinks and biodiversity hot spots through community participation and development of long-term plans for their sustainable and profitable use. Protection of the shoreline from wave action and erosion (precaution for cyclone/tsunami-endangered areas) and improvement of water quality in the mangrove wetlands. Development of effective community networks and the initiation of strategic community-based projects for the sustainable use and conservation of mangrove forests. Identify and develop sustainable alternative livelihoods to improve community welfare and reduce the exploitation of mangroves and other natural resources. Provide an incentive for local community member participation in the EMR process via a fair wage paid to those employed on both the restoration itself and the ongoing monitoring and management follow-up activities

9 3. Results Dissemination of knowledge, both scientific and indigenous, on Ecological Mangrove Restoration methods. Working examples of successful EMR are found in Florida at West Lake via work that Robin Lewis has done there over a decade ago, as well as in Indonesia around the village of Tiwoho in N. Sulawesi where MAP Indonesia and the local NGO, KELOLA, restored an area of abandoned shrimp ponds utilizing the EMR technique (Lewis 2005; Earthrise 2011). EMR Training Workshop in Thailand Field-work during EMR Training Assessing hydrology of site Fig 2- CBEMR in action Mapping site using knotted rope The following table summarizes CBEMR sites to date. Table 1 CBEMR Sites and Results Site Location and site type Year Restored No. ha Current Status Comments Block number (62), Pyinalan Reserve, Laputta Township, Ayeyarwady Division, Myanmar April-May (100 acres) MSN was able to return to the site in 2012 and from their report the recovery has been excellent. There photos also show very good growth and biodiversity of species. This site was create by MSN following two staff members attending a MAP EMR training in India in 2005 Due to isolation and Cyclone Nargis on May 2, 2008 which hit

10 N Sec E Sec Area was highly degraded and large areas cleared for extensive shrimp aquaculture. Laputta Township severely killing 80,000 people, the priority of MSN focused on relief and recovery work for a number of years. Undertaken by: Mangrove Service Network (MSN) Tiwoho, N. Sulawesi, Indonesia (abandoned extensive shrimp ponds and degraded mangrove) present 25 Good results on all shrimp ponds restored top mangroves This resulted in 60 ha of adjacent mangroves being saved from die-off with restoration of original hydrology of area Undertaken by: KELOLA, a local NGO in partnership with MAP- Indonesia Keezhathottam village, Palk Bay Region, Tamil Nadu, India (failed Forestry Dept. fish bone system restoration) Undertaken by: Organization for Marine Conservation, Research and Awareness (OMCAR) Recovery has been excellent and community is involved in maintaining fencing. Annual time lapse photos are involved. This EMR project was started by OMCAR and called MANGREEN following attending the MAP EMR training in India in Key to success has been a very high degree of local participation and mobilization combined with environmental awareness raising, especially with students. Green fencing using branches of Prosophis sp. by local people to keep out grazing cattle has been a major factor along with improved hydrology of deeper, wider channels