Tropical Wetlands For Climate Change Adaptation And Mitigation

Executive summaryWhy are tropical wetlands soimportant?Indonesia has more tropical peat swamp andmangrove forests than any other nation on Earth.The country has about 21 million hectares of tropicalpeat swamp forests and about 3 million ha ofmangroves. Globally this accounts for half of tropicalpeat swamp forests and almost a quarter of theworld’s mangroves.These ecosystems are highly productive and harboura unique range of aquatic and terrestrial biodiversity.They also play an important role in controllingthe delivery of water from terrestrial to aquaticecosystems and provide a buffering function againstthe transmission of pollutants across this interface.Mangroves are important sources of energy andnutrients for coral reefs, buffer coastal zones fromtropical storms, and are extremely valuable as fishand wildlife nurseries. Because of the accumulationof carbon over several millennia, Indonesia’s tropicalpeatlands and mangroves are among the largestterrestrial carbon pools on Earth (Donato et al. 2011,Murdiyarso et al. 2010).The rates of land-cover change occurring in tropicalwetlands are among the highest of any forest type.An estimated 45% of Indonesia’s peat forests havebeen deforested or drained, thus creating a shift intheir function from globally significant carbon sinksto globally significant sources of CO2 emissions. Ingeneral, 63% of emissions from peat swamp forestconversion arises from the decomposition of peat(Hergoualc’h and Verchot 2011).Tropical wetlands are of great interest because ofthe numerous ecosystem services at risk and thelarge amounts of greenhouse gas emissions thatarise from land conversion. Additional interests arerelated to their roles in mitigating climate changeand the important need to develop adaptationstrategies to climate change in these ecosystems.Economic opportunities are emerging through theglobal mechanism known as REDD (reducingemissions from deforestation and forest degradation,and enhancing forest carbon stocks in developingcountries) (Murdiyarso et al. 2010). Co-benefitsderived from the conservation or restoration ofstanding forests growing on wetlands, such asbiodiversity, aesthetics and ecotourism, non-timberforest products, and watershed protection are alsopotential financial incentives.Biogeochemical cycles of tropical wetlandsare complex, unique and globally significant.Understanding emissions, stocks and sequestrationwould improve the uncertainties in monitoring,reporting and verification (MRV) of the greenhousegas emissions associated with land-use and land-coverchange (LULCC).Science is neededClearly a scientific basis is needed to address thechallenges of managing these ecosystems in the faceof rapidly increasing land conversion and climatechange. As such, the Center for InternationalForestry Research (CIFOR) and the United StatesForest Service (USFS) convened an internationalworkshop and symposium in Bali, Indonesia in2011. The purpose of the workshop was to bringtogether Indonesian and international scientistsfrom a broad diversity of backgrounds andexperiences in both freshwater and coastal tropicalwetlands. They gathered to describe the state of thescience, significant research needs, and potentialcomprehensive multidisciplinary approaches toimplementing climate change adaptation andmitigation strategies.To address the purpose of the workshop, theprogramme included in-depth, break-out discussionsof smaller groups on themes such as greenhousegas flux processes, carbon stock changes due toLULCC, ecosystem modelling, use of remotesensing, links with the Intergovernmental Panel onClimate Change (IPCC) processes, and adaptation ofwetlands to climate change and human dimensions.As evidenced by the participation andpresentations synthesised in this paper (http://

Tropical wetlands for climate change adaptation and workshop-ontropical-wetland.html), the world’s leading tropicalwetlands scientists recognise the need for researchcollaboration and are committed to it. A strong,collaborative research effort is needed across theIndonesian archipelago, focusing on tropicalwetlands, to address information gaps relating to landuse and climate change. Fortunately, partnershipsare forming between Indonesian and internationalscientists to quantify carbon stocks, greenhouse gassequestration and emissions. It is also importantto have a well-coordinated research agenda that ishighly relevant to the policy community and decisionmakers. Such a scientific research agenda couldinform the public policy making processes for MRVand mitigation and adaptation strategies that arescientifically sound and socially acceptable. Whilethe discussions focused on Indonesian wetlands,the implications of research will be of relevanceto tropical wetlands through out the world, thusunderscoring the global significance of this research.Synergising mitigation and adaptationThe IPCC has developed methodologies forgreenhouse gas inventories that have been widelyused by parties to the United Nations FrameworkConvention on Climate Change (UNFCCC) forreporting purposes. The widely circulated report isoften used as a reference for mitigation strategiesand programmes. For developing countries likeIndonesia, adoption and implementation ofaccepted methodologies and analyses is crucial in thedevelopment of mitigation strategies.The IPCC Guidelines (IPCC 2006) have a land-usecategory for wetlands that is essentially limited topeatlands, with subcategories suitable to temperatepeatland management. Unfortunately, thesecategories are not suitable for tropical peatlands,especially for the unique features of saline peatlandsfound in mangroves. Introducing additional activitiesto the IPCC Guidelines that are more relevant totropical peatlands (including restoration – rewettingand restoration) brings opportunities as well aschallenges. In addition, IPCC-listed activitiesthat involve the use of fertiliser sand fire wouldbe improved by the provision of new activity dataand new emission factors from tropical wetlands.Knowledge generated from collaborative researchon tropical wetlands in Indonesia can provideinformation of global relevance for the IPCCwetlands addendum.Given the innumerable ecosystem services of tropicalwetlands that are at risk, it is quite logical to includethem in the global, national and local climatechange adaptation agendas. Coastal wetlands suchas mangrove ecosystems have proven their value inreducing the vulnerability of low-lying coastal zonesto damage from storm surges, tropical cyclones,and to some extent tsunamis. Likewise, peat swampforests function as ‘landscape sponges’, reducingflooding in wet seasons and gradually releasing thewater during dry seasons.Climate change impacts that most affect tropicalwetlands and the people who depend on theminclude sea-level rise, increasing soil salinity, changesin temperature and rainfall patterns, and increasingfrequency and severity of cyclones and El Nińoevents. Adaptation strategies specific to thesewetlands are needed to protect ecosystem servicesfor future generations. Mitigation procedures thatpreserve ecosystem resistance and resilience to climatechange (e.g. REDD ) are also recommended as costeffective and ecologically sound adaptation strategies.Adaptation to the impacts of climate change needsto be mainstreamed into the economic developmentplanning and implementation process. Synergisingadaptation and mitigation strategies would enhancethe benefits for communities most vulnerable toclimate change.The way forwardBased on the presentations and discussions atthe Workshop on Tropical Wetland Ecosystemsof Indonesia, the following recommendationswere made:1. Multidisciplinary research studies are necessary tobuild a strong science-based approach that servesIndonesia’s need to protect its unique wetlandecosystems. National and international scientistsworking on wetlands issues should facilitatecollaborations to address key policy issuessurrounding tropical wetlands, climate changeadaptation and mitigation.2. The scientific community should work closely tooptimise resources and avoid duplication. Vastlandscapes and crucial issues remain understudied

x   Daniel Murdiyarso, J. Boone Kauffman, Matthew Warren, Emilia Pramova and Kristell Hergoualc’hin Indonesia. Improved communication andcollaboration among agencies would minimiseunnecessary overlaps. Regular meetings thatfacilitate exchange of knowledge should bepromoted as they will assist in advancing thescientific wealth of Indonesia.3. Carbon-rich tropical wetland ecosystemsincluding mangroves and peatlands should beconsidered as high priorities in climate changeadaptation and mitigation strategies throughoutthe world. Given the abundance of tropicalwetlands, Indonesia has much to offer in theglobal climate agenda, such as the REDD mechanism.4. The state of the science related to carbonand nitrogen cycling, the dynamics ofLULCC and associated human dimensionsare key components of the research agenda.Comprehensive field measurements should beencouraged to accurately quantify greenhouse gasfluxes and carbon stock changes resulting fromLULCC in tropical wetlands.5. Greenhouse gas flux is a complex interplayof biogeochemical processes and land-usedynamics, which are largely driven by land-usedecisions made by local peoples, industries andgovernment policies. Modelling tools may bedevised to simulate land-use trajectories and theirimplications.6. Remotely sensed determinations of LULCCsupported by ground-truth data should beextensively used to reduce current uncertaintiesin quantifying the extent and carbon stockchanges in tropical wetlands.7. The existing IPCC Guidelines require substantialinputs to address the gap of the understatedroles of tropical wetlands. The next IPCCprocesses will require close collaboration betweengovernments and scientific community.

1. IntroductionMatthew Warren, Daniel Murdiyarso and Boone KauffmanTropical wetlands are among the most productiveecosystems on Earth, containing unique aquatic andterrestrial communities high in biodiversity (Posaet al. 2011). Wetland forests occurring on organicsoils –mangroves and freshwater peat swamp forests–are ubiquitous along coastlines and on coastal plainsthroughout the tropics. Inland peat swamp forestsalso occur within river basins at higher watershedpositions (Anshari et al. 2010). Page et al. (2011)estimated that there were 441,025 km2 of tropicalpeatlands globally, distributed throughout 61countries in Africa, Asia, Central America and theCaribbean, South America, Australia and the Pacific.The majority of tropical peat forests (about 56%)occur in southeast Asia (Page et al. 2011). Mangroveforests occur exclusively in coastal and estuarineenvironments, and extend beyond 23.5 latitudeinto subtropical regions. Globally, about 140 000–152 000 km2 of mangrove forests are distributedthroughout 118 countries (Giri et al. 2011).Southeast Asia and the Indo-Pacific are consideredcentres of mangrove distribution and diversity.Indonesia alone contains about 23% of the world’smangrove forests (Giri et al. 2010). Historically,tropical wetlands have received little attention inscientific literature and are among the lesser studiedtropical ecosystems. However, large-scale greenhousegas emissions associated with deforestation and forestdegradation from land conversion and recurringcatastrophic fires have sparked international concernover the fate of tropical wetlands. Because of theirexceptional carbon storage and potential to becomelong-term sources of greenhouse gas emissions,the influence of tropical wetlands on the globalcarboncycle is highly disproportionate to theirspatial extent.Many threatened flagship species for conservation(including orangutans, rhinoceroses, Sumatrantigers, and flora such as Nepenthes pitcher plants andorchids) find refuge in Indonesia’s peat forests andmangroves. Peatlands and mangroves also providenumerous ecosystem services to populations thatrely on them for life and livelihood (Table 1.1).Coastal wetlands, especially mangroves, supplyenergy and nutrients to coral reefs and maintainfisheries by providing nursing and breeding habitat.Tropical wetlands protect inland areas fromerosion, and dissipate energy from storm surgesand to some extent, tsunamis. Mangroves buffermarine ecosystems from terrestrial sedimentationand pollutants. Peatlands and mangroves alsostore an immense amount of carbon from thesteady accumulation of organic matter over severalmillennia (Donato et al. 2011, Page et al. 2011).Recent studies demonstrate that carbon pools inpeat and mangrove forests are 3–5 times higherthan those of upland tropical, temperate and borealforests, emphasising their significance in the globalcarbon cycle (Murdiyarso et al. 2009, Donato et al.2011). Ironically, deforestation rates of tropicalwetlands are higher than any other tropical foresttype, and drainage, clearing and burning continueat an alarming pace (Langner et al. 2007, Miettinenand Liew 2010a, Miettinen and Liew 2010b,Giri et al. 2011).The ecosystem services and carbon storage of tropicalwetlands are extremely vulnerable to the negativeeffects of climate change. Rising sea levels andincreased frequency and severity of tropical cyclonesare predicted for the next century, which will largelyimpact coastal wetlands and low-lying islands.Furthermore, altered precipitation patterns andincreasing frequency of extreme climate events (suchas drought associated with the El Nińo SouthernOscillation) may increase the susceptibility oftropical wetland forests to fire (Li et al. 2007).Landconversion results in immediate, massive carbonfluxes to the atmosphere from deforestation and

2   Daniel Murdiyarso, J. Boone Kauffman, Matthew Warren, Emilia Pramova and Kristell Hergoualc’hTable 1.1. Ecosystem functions, goods and services that can be quantified for tropical wetland forestsFunctionGoods and servicesQuantifierWater regulationWater supply to local communitiesWater yield: m3 fresh water/household/year; seasonal discharge/baseflow (m3/s)Climate regulationAtmospheric CO2 sequestrationMg carbon captured/ha/yearBreeding/nursing habitat for reefand offshore fishFishery production/protein sourceAnnual catch (Mg/year)Wave energy attenuation,substrate stabilisationCoastal defence/protection ofsettlements and infrastructureNumber of households protected,dyke maintenance costs avoided etc.Biodiversity conservationHabitat for endangered, threatened orvulnerable speciesNumber of species protectedTimber productionHigh value timberm3 timber/ha/yearNon-timber forest productsFruits, seeds, palms, ferns, honey, fungi,medicinal plants, fish, crabs, etc.Economic value: monetary unit/year;kg product consumed/yearCultural/heritageUse of traditional religious sitesFrequency and number of peopleusing siteEcotourismBoat rides, wildlife viewing, camping, etc.Number of tourists/year; incomegenerated from tourismNote: ‘Quantifier’ refers to units which can be used to measure goods and/or services.burning (about 255 MgC/ha) followed by longerterm oxidative losses depending on hydrologicalconditions (Hooijer et al. 2010, Murdiyarso et al.2010, Hergoualc’h and Verchot 2011). Murdiyarsoet al. (2010) estimated that 25% of all carbonemissions from converting peat forest to oil palmplantation (a wide-spread land-use transition inIndonesia) occur from initial burning to clear theland. During the unusually severe fire season of1997, drought conditions prompted opportunisticand uncontrolled burning, eventually affecting over2 million ha of wetland ecosystems throughoutIndonesia (Taconni 2003). Burning during the1997 fire season resulted in losses commensuratewith the 1.5 PgC average annual flux from globalland-use change in1990–2005 (Page et al. 2002, LeQuéré et al. 2009). In addition, the smoke haze andtransboundary pollution that defined the 1997 firesis now recurrent, with severe economic and publichealth impacts (Langmann and Heil 2004).Wetland degradation negatively affects numerousecosystem services, many of which are essential forthe reduction of societal vulnerability to currentclimate hazards and future climate change. Inaddition, greenhouse gas emissions from large-scalewetland drainage and degradation can contributeto additional climate forcing. The interconnectivityamong ecosystem services, climate adaptation andmitigation, vulnerability of large carbon pools toloss, and biodiversity conservation presents bothopportunities and challenges for tropical wetlandmanagement. Clearly, there is a strong interest insustainable wetland management and economicdevelopment. Implementation of science-basedpolicy is needed to balance conservation, climateand economic development agendas. To addresscurrent research needs and opportunities, aninternational scientific workshop was held in Bali,Indonesia attended by tropical wetland scientistsfrom throughout Indonesia and their internationalcounterparts. The objectives of the workshop wereto assess the current state of the science, significantresearch needs, and strategic multidisciplinaryapproaches for the implementation of climate changeadaptation and mitigation strategies specific totropical wetland forests. The subsequent chapters ofthis paper summarise the outcomes of working groupdiscussions on six broad themes relevant to tropicalwetlands research:1. Greenhouse gas flux processes in tropicalwetlands2. Land-use and land-cover change and carbonstock changes in tropical wetlands

Tropical wetlands for climate change adaptation and mitigation   33. Ecosystem modelling – predicting future wetlandscenarios with climate change4. Use of remote sensing – wetlands detection andmonitoring5. The IPCC Guidelines and processes in relation totropical wetlands6. Adaptation of wetlands to climate change andhuman dimensions.Issues related to greenhouse gas fluxes and changesassociated with land use are des

3 Ecosystem carbon stocks and land-use and land-cover change in tropical wetlands 10 3.1 Background 10 3.2 Land-use change 11 3.3 Carbon stock changes associated with land-use changes 12 3.4 Knowledge gaps 12 3.5 Challenges to carbon stock and land-use and land-cover change assessment 13 3.6 Emerging issues and recommendations 14