Community-Based Mangrove Planting Handbook For Papua New Guinea

INTRODUCTIONIn Papua New Guinea (PNG), many coastal communities depend onmangroves for their livelihood. Mangrove trees have been harvested overgenerations for construction materials and firewood. Mangroves provide ahabitat for fish, crabs, shellfish, birds, and reptiles.Mangroves also provide a natural defense against storm surges, coastalerosion, and coastal flooding. An analysis conducted by government’sClimate Change and Development Authority (CCDA) has highlightedcommunity-based mangrove planting as a cost-effective measure forcoastal communities. Unfortunately, overexploitation and degradation ofmangrove areas means communities are losing this protection.This handbook is an initiative of the government to address the impactsof climate change. It presents a step-by-step guide on how to rehabilitatemangroves. Although the main purpose is to address coastal flooding, thishandbook has been designed to be applicable to planting mangroves forall purposes, including carbon absorption, conservation, fisheries, andecotourism, among others.This handbook outlines five activities, including (i) creation of a projectwork plan; (ii) site preparation; (iii) planting; (iv) monitoring and training;and (v) project funding.1

CHAPTER I: CREATION OFA PROJECT WORK PLAN1. DEFINING GOALSThe first step is to define project goals. There are four main goals:(i) Protection of coastal areas. Planting mangroves can reduce shorelineerosion and can protect coastal communities against coastal flooding, highwinds and waves, and tsunamis.(ii) Restoration of a mangrove ecosystem. The aim is to supportlivelihood without destroying the mangrove forest. This means sustainablyharvesting mangrove products such as firewood, timber, and other marineproducts such as crabs, fish, and shells.(iii) Conservation of existing mangrove forests. This provides breedinggrounds for fisheries and preserving biodiversity. This can be achievedthrough the creation of protected sites, national parks, nature reserves,and wildlife sanctuaries.(iv) Carbon absorption (sink). Mangroves absorb more carbon than theother land-based forests.2. DEVELOPING A BASIC WORK PLANA workplan1 will outline what needs to be done by participants. It will(i) include all essential tasks, reducing the chance of forgetting or missinga step when activities start;(ii) break long-term goals into several smaller steps;(iii) prioritize activities according to their importance and how easy theyare to implement;12See Appendix A for an example of a work plan.

(iv) assign tasks to individuals or defined groups to make sure no tasks areduplicated and establish clear accountability;(v) state how individual or defined group performances will be assessedand what the implications of poor performance will be;(vi) set expectations for project progress and establish a project schedulethat can be tracked and monitored; and(vii) help to develop a budget2 and ensure adequate adequate fundsare available.2See Table A1 and Table A2 to develop your budget for income and expenses.3

CHAPTER II: SITE PREPARATION1. SELECTING A PROJECT SITEThere are criteria in identifying and selecting your project site.Table 1 presents these criteria.Table 1: Site SelectionFirst stage(general projectarea)(i) Natural suitability(can be one or several)Possible sitesDegraded area—The site is previously a mangrovearea which has been degraded;Gap—The site is a gap within the nondegradedstands;Mudflat—The site is on a mudflat with barrier islands;River—The site is on an open area along a brackishriver;(ii) SocioeconomicsuitabilitySecond stage(specific project site)(i) Natural suitability(specific)Adaptation value—It is expected that the communitywill be better protected against coastal flooding aftermangroves have been rehabilitated.Possible sitesNatural growth—There are signs of secondary growthor sparse vegetation with a few mangrove speciesgrowing.Correct zonation—The site is not submerged bymore than 1.5 meters in saltwater, as this prevents orminimizes barnacle infestation.Sheltered area—There is limited or no exposure tostrong waves, currents, and winds.Even tides—The tide is such that there is an evenperiod of inundation and drought. This is a rule ofthumb that varies across species.Tidal flat —The site is a tidal flat. These areas are bestfor expansion of mangrove stands;Continued on next page4

Table 1 continuedSecond stage(specific project site)Possible sitesLack of seagrass —The site is not a seagrass bed;Few pests—Avoid areas that are highly infested withpests such as crabs and barnacles;Area of accretion—mangrove seedlings will growin areas of soil build up, not in areas that are beingeroded;(ii) SocioeconomicsuitabilityConflict of interest—Rehabilitation will not conflictwith existing or future land use and/or developmentneeds.Community buy-in—A clear majority of thecommunity and its leaders support mangrove plantingin the proposed area;Landowner agreement—No individual communitymembers have a claim to the mangrove area andoppose rehabilitation.Source: Simon Wright & CCDA Technical Working Group.After selecting the project site, proceed with the next steps.1.1 SITE EVALUATIONSite evaluation is very important. A successful project can only be carriedout if the characteristics and conditions of the site are well understood.The seedlings survival guidelines and actions are adapted from Maniwavie(2012) and from the Mangrove Action Plan’s “5-steps to EcologicalRestoration of Mangroves” guide.First, consider the possible survival of seedlings that are going to beplanted. This will involve observing certain environmental factors todetermine whether your seedlings will have a high or low chance ofsurvival.Here are some guidelines:(i) The single most important factor for high mangrove survival is to plantin sites which are not exposed to winds and waves. Mangroves survivebest in areas protected from these harsh environments.5

(ii) Mangroves survive better in areas close to forested places, next to landwith good soils and streams, or where dead leaves accumulate.(iii) Mangroves thrive best in places with a mixture of mud and gravelsediments. They do not do well in sandy sediments.Knowing these information will help you decide where to plant and avoidreplanting in problematic sites thus minimizing wasted time, labor, andproject funding.1.2 FRUITING SEASONUnderstand the patterns of mangrove reproduction: when the seeds andfruits or propagules are produced (flowering or fruiting seasons), andwhere the seeds and fruits are distributed.Here are the steps:(i) Identify which species would naturally occur at your site.(ii) Ask locals about the species that previously grew on the site.(iii) Show pictures of species which can make recollection andidentification easier and more accurate.(iv) Conduct a basic survey of the species occurring on or near the site togenerate your own information and compare with the local knowledge.(v) Identify seeds that wash up onto the site.(vi) Understand the pattern of reproduction of suitable mangroves.It is important to know when seeds will be available for collection. Usepreserved specimens or look at photographs of different mangroves as aguide.1.3 RECORDINGMake a simple record of the type of seeds following Table 2.6

Table 2: Reproduction GuideSpeciesTypeof ths availableJanFebMarAprMayJunJulAugSepOctNovDecSize atMaturityYellowfruit skinSource: Simon Wright & CCDA Technical Working Group.Request for assistance from local officials, nongovernment organizations(NGOs), and others if needed, to fill the table.It also important to understand the dispersal pattern of suitablemangroves.The seeds of the various mangrove species near the site will travel indifferent ways and in different distances. Some may not reach the site.You may also find that seeds from mangroves from another site that makeit to your site could be suitable for planting. Use Table 3 below for thispurpose.Table 3: DispersalSpeciesAvicenniamarinaDistance from Siteto Seed SourceMonths 1–4km5km *Presence/absence ofseedsat siteYesNokm kilometerSource: Simon Wright & CCDA Technical Working Group.Request for assistance from local experts, officials, NGOs, and others ifneeded, to fill the table.1.4 ZONATIONZonation refers to the distribution of mangrove species across theintertidal zone.Zonation patterns are characterized by a sequence ofplants that occur parallel to the shoreline.7

Here are the steps in determining the zonation:(i) Identify the zonation of nearby healthy mangroves. This is most usefulif these nearby areas resemble the conditions at the chosen site.(ii) Observe the zonation of mangroves, going from the shore to the land(or terrestrial margin), noting where different species grow.(iii) Sketch a basic diagram of the zonation pattern, using Figure 1 as anexample.(iv) Use a tape measure to measure how wide the different species zonesare and note them down.Figure 1: A Basic Illustration of Mangrove ZonationA. marinaSonneratiaR. stylosaR. apiculataR. apiculataR. mucronataB.gymnorrhizaA. albaA. officinalisB. sexangulaXylocarpusMangroveassociatesMud, sandy, sandy loam, gravelly sand, rocky or coral rubbleMud, sandy loam,muckMud, sandy loam,sandyTerrestrialsoilSource: Modified from Whitten et al., 1987.8

Identify the zonation pattern of your mangrove planting site and theirdistributions and compare this to the substrate pattern of the mangrovearea used for your zonation chart.1.5 SUBSTRATE OR SOIL TYPEUnderstand the substrate or soil type of the site. The different speciesof mangroves prefer different types of substrates and knowledge of thesubstrate type at the site will help determine which species are needed.Observe the substrate types in the same place where the zonation patternwas observed.Here are the steps:(i) Mark the substrate pattern on the zonation chart and note how how itmatches up to the zones and species.(ii) Identify the substrate types on your mangrove planting site and theirdistribution.(iii) Compare this to the substrate pattern of the mangrove area used forthe zonation chart.Table 4: How Different Substrate Characteristics Influence SpeciesSubstrateDescriptionTypical speciesMudA mixture of silt and clay withorganic matter. It can be as shallowas 2 centimeters (cm) or deeperthan a meter. Avoid mud that smellsvery strongly of rotten egg or is sosoft you sink up to your knees into it.Bruguiera cylindricaBruguiera gymnorrhizaCeriops tagalRhizophora apiculataRhizophora mucronataRhizophora stylosaGravellysandA mixture of gravel (pieces of rocksand stones) and sand.Avicennia marinaOsbornia octodontaSonneratia albaRhizophora stylosaXylocarpus rumphianaRocky orcoral rubbleThese substrates are generally quitehard, but with thin layers ofsediments.Avicennia marinaPemphis acidulaRhizophora apiculataRhizophora stylosaSonneratia albaContinued on next page9

Table 4 continuedSubstrateDescriptionTypical speciesSandySandy substrates normallyconsist of very small grains ofrock, shell and coral with littleor no organic matter. Like mud,sand may be as shallow as 2-3cm or as deep as several meters.Osbornia octodontaRhizophora apiculataRhizophora stylosaSonneratia albaSandy loamA mixture of clay, silt, sand andorganic matter.Avicennia marinaRhizophora apiculataRhizophora stylosaSonneratia albaSonneratia caseolarisMuckSimilar to mud except that itcontains more organic matterthan mud. It also tends to bedeeper, starting at more than10 cm thick up to a few meters.Like mud, muck may have thesame foul, rotten egg smell;if so, planting should not beattempted.Bruguiera gymnorrhizaCeriops australisCeriops decandraCeriops tagalRhizophora mucronataSource: C.D. Field. 1996. Restoration of Mangroves Ecosystems.1.6 TIDESThe tide is the single most important factor in establishing a successfulmangrove restoration project. Understand the normal patterns thatcontrol the distribution and growth of mangroves in the area. Know howdeep the tide submerges the site.Here are the steps:(i) Go to the site elected and monitor the tides;(ii) Observe the limits of the high tides and low tides during a full moon ornew moon. These are the “spring tide” water marks;10

(iii) Observe the limits of the high tides and low tides during a half moon.These are the “neap tide” water marks. Average sea level is between theneap tide high and low water marks. Add the different tide water marks tothe zonation sketch, such as in Figure 2 below.Figure 2: Zonation and Tidal PatternsExtreme tide high waterSpring tide high waterNeap tide high waterAverage sea levelNeap tide low waterSource: Whitten et al. 1997.(iv) Understand the duration and frequency of the tides affecting the site.Monitor the duration of the tides and record how many hours each zone ofmangroves is submerged by water and how long the zones are dry.(v) Monitor how often the tide reaches a certain level each month and filla matrix similar to Table 5. For example, if all high tides of the site reach atleast 0 and 2.4m, then the flooding frequency of tides between 0 and 2.4mis 56–62 times (i.e., 2 high tides per day x 31 days per month 62 timesper month).Table 5: Tidal Inundation ClassesClassType of Tides thatare Flooded ByHeight AboveAverage Low TideFlooding Frequency(Times Per Month)1All high tides0–2.4 m56–622Medium high tides1–3.4 m45–593Normal high tides3.4–4 m20–454Spring tides4–4.6 m2–205Extreme tidesHigher than 4.6 m2m meterSource: Watson, 1928.11

The zonation chart should look something like Figure 3. This will be avaluable reference tool for future activities.Figure 3: A Diagram Representing Zonation in Mangroves alongthe Inundation LevelsSource: Modified from Whitten et al. 1987.1.7 DISTURBANCESIf the project site used to be covered by mangroves but is now barren, it isnecessary to understand what led to the degradation and what is preventingrecovery. Disturbances that cause mangrove degradation can be classifiedaccording to whether they are natural (caused by tides) or human-made.Here are the steps to determine disturbances:(i) Identify the causes of degradation of the mangrove site. Look at Table6 for a list of the most common stresses responsible for mangrove losses,and note which of these are relevant to the site and other nearby mangroveareas.(ii) Determine when the different stresses began or occurred, and whenthe mangroves began to degrade.12

(iii) As a general rule, the closer together the start of the stress and the startof the degradation, the more likely it is that one caused the other.Table 6: Examples of Stresses to a Mangrove SiteNaturalHuman-madeRiver mouth blocked by sandbankpreventing water flowSoil is hypersaline and too acidicusually after intensive farmingDrought leading to lack of fresh water orgroundwaterDrains, ditches, or dikes that divertfresh water away from mangroves(e.g. aquaculture ponds)Floods leading to too much salt orfresh waterRoads cutting through mangroveswithout drainage preventingwater flowOngoing storm surge (or cyclone)Domestic animals damagingseedlingsSoil is hypersaline and too acidic usuallyafter intensive farmingSource: Simon Wright & CCDA Technical Working Group.1.8 REMOVAL OF STRESSESOnce the stressors have been determined, take action to restore naturalgrowth and change community habits to reduce human-made destruction.Here are the guidelines:(i) Focus on the artificial stresses at this stage of the project. There is notmuch to do to alter most natural hazards.(ii) Prioritize solutions that can be made at once, rather than those thattake time. For instance, modifying constructions, such as putting a drainunder a road, can be quick and have immediate impact.(iii) Use Table 7 as a reference of possible solutions to human-madestresses, but note that this does not contain all possible stresses orsolutions.(iv) Use your knowledge of the community and environment toidentify other stresses and come up with solutions. Engage the help ofcommunity members.13

Table 7: Examples of Human-Made Stresses and SolutionsStressSolutionDomestic animals damagingseedlings e.g. pigs foragingPut up a fence to stop animals roamingthe mangrove area.Overconsumption of propagulesfor foodCreate and implement community laws toinstitute closure periods and/or harvestinglimits and restrict access to certain sites orcreate a mangrove management plan.Provide alternative crops.Overharvesting of wood,usually for fuel and constructionCreate and implement community laws torestrict harvest size.Provide alternatives, e.g., terrestrial woodtrees. Alternate fuelwood species withthe same burning capacity as mangrovespecies.Plastic and other rubbish smotherseedlingsDetermine source of rubbish, if localor distant. If local, implement a wastemanagement system for your communityand encourage neighboring communitiesto join.Boats being dragged or paddledover seedlingsSet aside and encourage communitymembers to use one main passage.People trampling seedlings whengathering wood or huntingEncourage community members to bemore careful of seedlings because they arenecessary for the long-term health of themangroves.Drains, ditches, or dikes that divertfresh water away from mangrovesRedesign diversions so that enough freshwater reaches the mangrove areas.Source: Simon Wright & CCDA Technical Working Group.2. CONSTRUCTING A NURSERYThe need for nurseries depends on the species to be grown and theenvironmental conditions of the site. Mangroves with large seeds or fruits,such as rhizophora, can be planted directly into the substrate withoutspending time in a nursery. Direct planting is considerably cheaper andeasier than having a nursery phase and planting from polypots or polybags.However, research has shown that an initial growth phase in a nurserytends to improve the chances of seedling survival, especially where thesubstrate is unstable or the seeds are small.14

Note that constructing nurseries has its own challenges, as shown inTable 8.Table 8: Problems Resulting from Poor Nursery SelectionProblems

communities across Papua New Guinea, to take up mangrove planting as a least cost method of coastal defense. Finally, I wish to acknowledge all those who contributed toward the review and eventual publication of this handbook, in particular the Asian Development Bank. I welcome and endorse this revised handbook as a demonstration of our