Journal of Tropical Forest Research 3 (1) : 36-53 (2019) Original article A Community Based Mangrove Rehabilitation of High Energy Coasts in Pedada Bay, Philippines Keita Furukawa1, 2, 3* Jurgenne H. Primavera4 Rona Joy A. Loma4 Christian L. Montilijao4 Jofel D. Coching4 Yvainne Y. Sta. Maria5 Fernando P. Siringan5 1Ocean Policy Research Institute, SPF, Toranomon, Minato-ku, Tokyo 1058524 Japan 2Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama, 2408531 Japan 3Association for Shore Environment Creation, Hiranuma, Nishi-ku, Yokohama, 2200023 Japan 4Zoological Society of London-Philippines, Brgy. Magdalo, La Paz, Iloilo City, 5000 Philippines 5Marine Science Institute, University of the Philippines, Diliman, Quezon City, 1101 Philippines *Corresponding Author, E-mail: [email protected] Received: Feb 13, 2019 Revised : May 7, 2019 Accepted : Jun 11, 2019 ABSTRACT For coastal communities, fringe mangrove forests can help to protect their coasts from high energy waves and provide various ecosystem services. Nevertheless, these forests are under threat of damage caused by climate change and variability and stress related to development. Coastal hydrology / morphology is one of key processes to be monitored and assessed to implement an appropriate management especially for mangrove rehabilitation. This paper reports on the lessons learnt from the Community based mangrove rehabilitation of a fringed mangrove project in the Pedada bay, Philippine. The sea floor level in the area was too low (less than 0.5 m below the Mean Sea Level or MSL) and exposed to high energy waves from the sea. A pair of breakwaters was constructed for reducing the wave energy, but sea floor level could not be amended artificially in January 2010. Thus, the first plantation attempt failed. Nevertheless, continuous monitoring of sea floor level has been conducted and the ongoing sedimentation processes been traced. The maximum sedimentation rate was recorded at 0.5 m / year in the region during 2012-2013. The survival rates of Avicennia marina, Sonneratia alba, and Rhizophora mucronata were 44.0 %, 73.6 %, and 0 %, respectively (during 2010-2013), due to differences in natural succession and tolerance of species. In 2013, the area was battered by Typhoon Yolanda (Nov. 2013), but the breakwaters and sheltered mangroves survived. These attempts emphasize the importance of an integrated management with community participation and a science based approach. Keywords: Mangrove restoration, Community based management, Coastal protection, Topography, Sediment transport. Journal of Tropical Forest Research 3 (1) : 36-53 (2019) 37 INTRODUCTION for any process that aims to return a system Mangrove forests provide various to its pre-existing condition (Lewis, 1990) and ecosystem services and are under threat due includes “natural restoration” or “recovery”. to an alarming rate of deforestation. A “Ecological restoration” includes “a process worldwide synergy between people and forests assisting in the recovery of an ecosystem that is significant (Lugo and Snedaker, 1974). Trees has been degraded, damaged, or destroyed” (Society for Ecological Restoration, 2002). provide timber and charcoal, while fish, Conservation and rehabilitation of mangrove shellfish, and benthos abound in the surrounding forests by various national and international waters provide foods. Furthermore, shore agencies is still on-going and the success of protection by regulating wave and current such activities is influenced by various socio- energy and sedimentation is one of the more economic, political, as well as environmental important services as a eco-system based factors such as climate change (Veettil, et al. disaster risk reduction mechanism (International 2019). Union for Conservation of Nature, 2016). One For those who lack an understanding fifth of all mangrove forests have been lost of the hydraulic situation as tides and waves, since 1980, and although loss rates are declining little attention is paid to the tidal inundation at 0.7 % per year, this is still 3 to 4 times higher frequency. It is linked with the micro-topography than the average global forest loss estimates and variations in sea level (Kjerfve, 1990). (Food and Agricultural Organization, 2003; Since micro-topography is controlled by the Spalding et al., 2010). dynamic process of tides and waves interacting In the Philippines, mangrove coverage with complex root systems (Massel et al., has declined from 500,000 ha in the early 20th 1999; Furukawa et al. 1997), inundation century (estimated by Brown and Fisher, 1918) frequency can change with the time frame to 132,500 ha in 1990 (Auburn University, (hours, days and seasons). Nevertheless, such 1993). The loss of mangrove forests has been temporal changes and variations are seldom associated with an increase in the number of taken into account in mangrove hydraulics converted aquaculture ponds for mollusks, (Lewis and Estevez, 1988). Recently, a fish, shrimps and crabs from mangrove forests numerical calculation was done to determine (Primavera, 1995, 2000). the microscopic interaction between the flow Various management and restoration and seedlings (Le Minor et al., 2019). efforts have since been implemented. As Nevertheless, the overall hydraulic suitability summarized by Lewis III (2005), the key terms is based on observations with the duration of and principles are “restoration” and “ecological inundation playing a vital role (Van Loon, restoration”. Both terms have to be defined 2016). carefully and understood thoroughly to avoid Since coastal ecosystems interact with any unexpected failure of restoration. The hydraulics, especially sediment transport, their term “restoration” has been adopted specifically restoration and conservation is embedded 38 Journal of Tropical Forest Research 3 (1) : 36-53 (2019) within the coastal protection measures as - Reclamation: The conversion of a “nature-based defences” (Narayan et al., 2016). waterbody or wetland area into a The study shows that coastal habitats have a more terrestrial-based system or into significant potential in reducing wave height a wetland above the mean water that varies with habitat and site. Moreover, level through some manmade activity. salt-marshes and mangroves can be a cost - Regeneration: Natural regrowth after effective restoration and conservation option a disturbance. under specific conditions. - Rehabilitation: Human activity aimed Under these circumstances, understanding at repairing the damaged or blocked the more dynamic hydraulic / topographic ecosystem functions. processes are needed during the planning, - Remediation: The cleaning up of a implementation, and monitoring phases of a polluted wetland site. mangrove ecosystem restoration. Furthermore, Nevertheless, restoration is used for to understand the dynamic processes, frequent more specific activities to return a degraded and continual monitoring is necessary. Thus, mangrove land to its pristine state; (of an it is important to determine the contribution ecosystem) [is] the act of bringing it back into, and awareness of stakeholders. as nearly as possible, to its original condition, renewing or bringing back into use. On the Rationales (Backgrounds of the Project) other hand, rehabilitation is a term used for Definition of action and success the restoration of degraded mangrove lands criteria of the project to a fully functional mangrove ecosystem, Some people use restoration as a more regardless of the original state of the degraded general term for managing the ecosystems. land (Field, 1998; Field, 1999). In that context, restoration is used as a collective expression for creating, altering, or improving ZSL-CMRP activities in Padada the ecosystems. For example wetland restoration Beach is defined as a group of the following activities Since the functions of mangrove forests (The World Association for Waterborne have declined due to erosion of the coast, a Transport Infrastructure, 2003); Community-based Mangrove Rehabilitation - Creation: The conversion of a Project (ZSL-CMRP) was initiated to persistent non-wetland area into a “rehabilitate” the missing functions of mangrove wetland through some manmade forests by the Zoological Society of London activity. (2018), using a plantation at the site. The - Enhancement: The alteration of project set a success criteria based on the existing wetlands to provide conditions survival rate of the planted mangroves and that did not exist previously, which natural (wild) succession. can increase one or more user-defined One of the ZSL-CMRP projects, values. implemented at the Padada Beach, East-South Journal of Tropical Forest Research 3 (1) : 36-53 (2019) 39 side of the Penai Island, is shown in Figure 1. along a line. No significant interactions between A community referred to the people’s organization structures and the sediments (or micro- formed in 2009 (Barangay Pedada Fisherfolks topography) were seen (Cruz et al., 2013). Association: BPFA). Within the project, The project started in March 2009 “Community-based” activity was defined as with a baseline survey of the coastal geology. an integrated activity of the BPFA that: 1) In June 2009, a People’s Organization (PO), constructed breakwaters in 2010 (based on a called the Barangay Pedada Fisherfolks design prepared by the engineering consultants Association (BPFA) was formed, and in AMH Philippines, Inc.), 2) planted, and consultations with the Municipal Local monitored, the mangroves together with ZSL, Government Unit (MLGU), ZSL,