Conservation and restoration of mangroves: Global status, perspectives, and prognosis

Ocean and Coastal Management 154 (2018) 72–82

Contents lists available at ScienceDirect

Ocean and Coastal Management journal homepage: www.elsevier.com/locate/ocecoaman

Conservation and restoration of mangroves: Global status, perspectives, and prognosis

T

Stephanie S. Romañacha,∗, Donald L. DeAngelisb, Hock Lye Kohc, Yuhong Lid, Su Yean Tehe, Raja Sulaiman Raja Barizanf, Lu Zhaig a

U.S. Geological Survey, Wetland and Aquatic Research Center, 3321 College Ave, Davie, FL 33314, USA U.S. Geological Survey, Wetland and Aquatic Research Center, Biology Department, University of Miami, Coral Gables, FL 33124, USA c Jeffrey Sachs Center on Sustainable Development, Sunway University, Jalan Universiti, Bandar Sunway, 47500 Petaling Jaya, Selangor, Malaysia d Department of Environmental Science and Engineering, Huaqiao University, Xiamen City, Fujian 361021, People's Republic of China e School of Mathematical Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia f Forest Research Institute Malaysia (FRIM), 52109 Kepong, Selangor, Malaysia g Biology Department, University of Miami, Coral Gables, FL 33124, USA b

A B S T R A C T Mangrove forests provide critical services around the globe to both human populations and the ecosystems they occupy. However, losses of mangrove habitat of more than 50% have been recorded in some parts of the world, and these losses are largely attributable to human activities. The importance of mangroves and the threats to their persistence have long been recognized, leading to actions taken locally, by national governments, and through international agreements for their protection. In this review, we explore the status of mangrove forests as well as efforts to protect them. We examine threats to the persistence of mangroves, consequences, and potential solutions for effective conservation. We present case studies from disparate regions of the world, showing that the integration of human livelihood needs in a manner that balances conservation goals can present solutions that could lead to long-term sustainability of mangrove forests throughout the world.

1. Introduction Mangroves are found chiefly in the intertidal zones of coastal tropical and subtropical regions of the world (Fig. 1). They can tolerate salinities from freshwater to hypersaline exceeding 100 parts per thousand. They can also thrive under much lower salinities, but their occurrence in terrestrial communities is limited by competition with other species better adapted to the terrestrial environment. Mangroves are physiologically a tropics-adapted group, and frost frequency and severity as well as minimum temperature requirements limit poleward expansion (Twilley, 1998; Saintilan et al., 2014). Mangroves were reported by Spalding et al. (1997) to occupy 18,100,000 ha worldwide, but this estimate of global coverage was revised downward to 13,776,000 ha by Giri et al. (2011), and then to 8,349,500 ha by Hamilton and Casey (2016). The distribution of mangroves, which includes 118 countries, is described in detail by Tomlinson (1986). At least 35% of mangrove forest area was lost worldwide during the 1980s and 1990s alone (Valiela et al., 2001), with losses of 50–80% in some regions (Wolanski et al., 2000). The global loss of mangroves can be attributed largely to human population growth and development in ∗

the coastal zone. Specific reasons are urban development, aquaculture, conversion to agriculture such as rice farming, and overexploitation of timber. These losses matter, as mangroves provide numerous services and benefits to nature and to people. Mangroves play an important role in buffering coastlines against storm surges and tsunamis through wave attenuation (Kathiresan and Rajendran, 2005; Wolanski, 2007; Barbier et al., 2008; Teh et al., 2009). Studies have shown that the flooded area produced by Hurricane Wilma in 2005 in southwestern Florida would have extended 70% further inland without the protection of the 6–30 km zone of mangroves (Zhang et al., 2012a; Liu et al., 2013, Fig. 2), and mangroves reduced the loss of human life from the 1999 cyclone that struck Orissa, India (Barbier, 2016). Loss of mangroves will result in less protection from both flooding and high winds. Some countries, such as Guyana, have engaged in educational outreach to alert the public about the potentially catastrophic consequences to mangrove deforestation (Fig. 3). Numerous studies show that mangroves provide nursery habitat for juvenile coral reef fishes of many species (Nagelkerken et al., 2000). Laegdsgaard and Johnson (2001) showed that mangroves, especially the prop roots of Rhizophora,

Corresponding author. E-mail address: [email protected] (S.S. Romañach).

https://doi.org/10.1016/j.ocecoaman.2018.01.009 Received 16 February 2017; Received in revised form 8 January 2018; Accepted 8 January 2018 0964-5691/ Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

Fig. 1. Map showing the global distribution of mangroves (in black). Source: United Nations Environment World Conservation Monitoring Centre (UNEP-WCMC); Giri et al. (2011); version 1.3, http://data.unep-wcmc.org/datasets/4.

2. Status of and current threats to mangroves

provide structural heterogeneity that is favorable both to prey attempting to avoid predators and to predatory fish searching for invertebrate prey hiding within the root structure. Mangroves also serve as sinks for carbon, not only through accumulation of living biomass, but also through litter and dead wood deposition, including the trapping of sediments delivered from the uplands. Carbon in mangrove sediments does not turn over in the same way it does in terrestrial soil, but builds up vertically in response to sea level rise (SLR) (McLeod et al., 2011). Another service provided by mangroves is that of a nutrient sink. Denitrification in the anaerobic environment (Ewel et al., 1998) and nitrogen-fixation by certain bacteria and cyanobacteria associated with mangrove mud and with above-ground root systems (Kimball and Teas, 1975; Pelegri and Twilley, 1998) can improve water quality from wastewater inputs. Worldwide, natural resources fall under various levels of management and ownership, ranging from private to government ownership (Berkes, 2004). Because of the recognized importance of mangroves and the continuing threats to their persistence, actions have been taken internationally and for the conservation and sustainable use of wetlands. Protective authorities include the United Nations Forum on Forests (UNFF), Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), Convention on Biological Diversity (CBD), United Nations Framework Convention on Climate Change (UNFCCC), Convention on Wetlands of International Importance especially as Waterfowl Habitat (Ramsar Convention), Convention for the Protection of World Cultural and Natural Heritage, and the Convention on the Conservation of Migratory Species of Wild Animals. These agreements have resulted in the protection of large areas of mangrove forests globally. In addition to conservation agreements at the international level, efforts by individual nations to protect or restore these forests have varied from mandated protection by governments to locally-initiated efforts. Human use of those resources varies depending on the level of protection. Overall, the global decline of mangroves has slowed, but additional actions need to be taken to ensure their longterm survival (Alongi, 2002). In this review we provide overviews of (1) Status of & Current Threats to Mangroves, (2) Threats for the Future (3) Failures of Current Conservation Approaches, and (4) Innovation and Success in Mangrove Conservation.

Mangroves exist on every continent except Antarctica. In this section, we will limit our discussion to Asia (Fig. 4) and the United States of America (U.S.; Fig. 5). Asia encompasses the largest land area of mangroves and the U.S. has been the focus of many decades of published research on mangrove forests. Although the status of mangrove forests varies by country and region, many mangrove forests experience similar threats to their persistence from urban development and timber harvest to conversion for other land uses such as agriculture and aquaculture, which we describe in more detail in this section.

2.1. Asia Asia has the largest land area of mangrove forest, encompassing 42% of the world's mangroves (Giri et al., 2011). Within Asia, Indonesia and Malaysia have the largest mangrove areas. We focus on Malaysia and China as representative of examples of status and change. Malaysia has about 575,000 ha of mangrove forest (Fig. 4), reduced from 695,000 in the 1970s; that is, reduced by 17%, due to land conversion/reclamation for agriculture, aquaculture, urbanization, infrastructure development and natural causes mainly from coastal erosion. Located in the State of Perak, Matang Mangrove Forest is the largest mangrove forest in Malaysia. Covering an area of about 40,000 ha, the Matang Forest was designated as a Permanent Forest Reserve since 1904 with efforts to preserve the forest dating back to 1902, making it the oldest mangrove reserve in Malaysia. Although Matang Forest is not designated as a Ramsar site, it is a sustainable and well-managed forest system that produces a constant yield of renewable forest resources while maintaining ecosystem biodiversity and richness. There are currently seven Ramsar sites in Malaysia—four in Peninsular Malaysia, two in Sabah and one in Sarawak. The three Ramsar sites, Pulau Kukup, Sungai Pulai and Tanjung Piai, are located in the State of Johor. These sites are particularly rich in mangroves and intertidal mudflats. Located about 1 km offshore from the southwestern region of Johor, Pulau Kukup is an uninhabited and intact mangrove island of approximately 650 ha surrounded by extensive (800 ha) intertidal mudflats. The island is important for flood control and protection from storm events and coastal erosion. Sungai Pulai, over 9000 ha, is Peninsular Malaysia's largest estuarine mangrove system, which also includes seagrass beds, intertidal mudflats and an inland freshwater riverine forest. It provides 73

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

Fig. 2. Map image showing inundation area of Hurricane Wilma on in the mangrove region of southwestern Florida USA (reproduced with permission from Keqi Zhang and Elsevier).

shoreline stabilization and flood prevention for adjacent villages. Tanjung Piai, over 500 ha, is an 8 km strip of coastal mangroves and intertidal mudflats at the southernmost tip of continental Asia. The mangroves along Tanjung Piai prevent excessive sediments from entering the waterways and help stabilize the shoreline against high-energy wave action. As the last remnants of a formerly 17,000 ha area, Sarawak Mangrove Forest Reserve of Kuching Wetlands National Park is a mangrove forest covering approximately 6600 ha. With over 78,000 ha of mangrove forest and peat swamp, Lower KinabatanganSegama Wetlands of Sabah is Malaysia's largest Ramsar site, formed by three protected forest reserves—Trusan Kinabatangan Forest Reserve, Kuala Maruap and Kuala Segama Forest Reserve, and Kulamba Wildlife Reserve. The 24.2 ha Kota Kinabalu (KK) Wetland of Sabah is the most recent site being designated by the Federal government as a Ramsar site on March 2017. Located just two kilometers away from the KK city, the patch of mangrove forest is what remains of the original forest along the entire coastline of the KK city before urbanization, making it a site of

cultural heritage significance. In Peninsular Malaysia, about 1282 ha (or about 1%) of mangroves were lost per year between 1990 and 2010 (Hamdan et al., 2010, 2012). The main reasons for such loss were identified as land conversion for mainly agriculture and aquaculture, as well as coastal erosion. Recently, Richards and Friess (2016) reported that more than 15,800 ha (or 2.83%) of mangrove area was lost between 2000 and 2012. Over that period, deforestation of mangrove forests for aquaculture, rice and oil palm plantations was identified as the major cause of the loss. They attributed 38% of this mangrove loss in Malaysia to conversion of mangrove forests to oil palm plantations. Malaysia's Matang Mangrove Forest, well-known for its sustainable forest management, is susceptible to pollution from upstream industrial areas. Over-exploitation of scarce marine resources and mangrove trees, in combination with pollution from nearby oil palm plantations, are the major concerns of the Marudu Bay Mangrove, Sabah. Logging, soil erosion, loss of wildlife, agricultural impacts, including water quality deterioration, habitat loss, 74

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

Fig. 3. Example signage in Guyana showing the government's effort to inform the public about the protection benefits provided by mangroves against storm surge (photo credit: Carinya Sharples/Mongabay; used with permission).

Fig. 4. Map showing the extent of mangrove distribution (in black) in Asia. Source: UNEP-WCMC, Giri et al. (2011).

species, which often occupy deforested mangrove areas, may restrict the re-growth of mangroves. Development and over-exploitation exacerbating soil erosion are some of the common threats faced by wetlands in Johor such as those of Pulau Kukup, Sungai Pulai and Tanjung Piai, which are mainly scattered along the coastal areas and rivers. The largest country in Asia, China, has a natural distribution of mangroves that extends from Yulin Port, Hainan (18° 9′ N) to Fuding, Fujian (27° 20′ N) including Fujian, Guangdong, and Guangxi provinces, Hong Kong and Hainan. The total area of mangrove forest is

and oil palm plantations and mills are identified by Sabah Biodiversity Centre (2011) as problems that could potentially affect Lower Kinabatangan-Segama Wetlands integrity as one of the Ramsar sites. Located downstream of a high population density and development area, the Kuching Wetlands National Park is at risk of environmental degradation from untreated solid and liquid waste, land-clearing activities, as well as a nearby stone quarrying operation. Non-native plant invasions are likely to have a significant ecological impact where they displace native species. For example, plants such as Acrostichum aureum and Acanthus 75

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

Fig. 5. Map of the extent of mangrove distribution (in black) in the United States of America, showing the greatest coverage in Florida. Source: UNEP-WCMC, Giri et al. (2011).

in mangrove wetland ecosystems. This includes pollution from the application of pesticides and animal waste. For example, a Sphaeroma bloom in 2010 in Hainan and Guangxi was caused by domestic duck farming, and caused the death of a mangrove forest (Fan et al., 2014). Another example is in Quanzhou Bay of Fujian, where pest damage to an Aegiceras corniculatum mangrove forest was likely caused by pollution from aquaculture development (Zuang et al., 2011; Li, 2012a,b).

25,000 ha currently, but has been recorded as great as 250,000 ha. Mangroves experienced a 50% loss in China, from 40,000 ha in 1957 down to 18,800 ha in the mid-1980s (He and Zhang, 2001). Thirtyseven species, representing 20 families and 25 genera, include 26 true mangrove species and 11 semi-mangrove species in China (Li and Lee, 1997; Wang, 2007). Mangroves are categorized as true mangrove and semi-mangrove species based upon their living environment (Wang et al., 2011). True mangroves are species that are strictly distributed in the intertidal zone while semi-mangroves are species that could both grow in the intertidal zone and on land. Mangrove forest in mainland China makes up just 0.14% of the world's mangrove area, but holds one third of the world's mangrove species (Wang, 2007). Therefore, mangrove conservation in China plays an important role in biodiversity conservation of the world's mangrove forests. Currently, there are 35 mangrove conservation areas in China, which are managed by central or local governments (Chen et al., 2009). Among the 49 Ramsar Convention sites in China, some focus specifically on protecting mangroves, such as the Dongzhaigang Mangrove Nature Reserve (5400 ha), Mai Po Marshes and Inner Deep Bay (1540 ha), Shankou Mangrove Nature Reserve (4000 ha), Fujian Zhangjiangkou National Mangrove Nature Reserve (2360 ha) and Guangxi Beilun Estuary National Nature Reserve (3000 ha). China has experienced three stages of mangrove forest land conversion: (1) transformation to agricultural areas in the 1960s and 1970s, (2) development of aquaculture in mangrove forests during 1980s, and (3) recent urbanization via development of ports, docks, and business districts (Wang, 2007). For example, in the Tieshan port of Beihai, Guangxi province, construction will result in mangrove forest loss near 370 ha. Despite the efforts of artificially planting mangrove forest in recent years, the mangrove loss from this project may overcome the total amount of mangrove trees planted in all of China during one year. Invasive species also threaten the persistence of mangrove forests. Spartina alterniflora is one of the most successful invasive species in mangrove wetlands and has dispersed coast-wide to all mangrove sites in China. A species used in reforestation efforts, Sonneratia apetala, has increasingly caused concerns about its potential to invade native mangrove forests (Ren et al., 2009). Human behavior has also caused serious pollution and increased disease spread and pest damage

2.2. United States of America In the U.S., the State of Florida contains by far the largest area of mangrove swamp, approximately 190,000 ha (Fig. 5; Odum et al., 1982). The area of mangroves on the northern Gulf Coast was recently estimated for Texas at 3790 ha, up from 2181 ha in 1990 (Armitage et al., 2015). In Louisiana, chill-tolerant black mangrove (Avicennia germinans) shrubs have interspersed into saltmarsh at their northern extreme of their current range and have rapidly recolonized and expanded in the last three decades (Michot et al., 2010; Osland et al., 2013, 2015). Mangroves are not native to Hawaii, but have been introduced, with both positive and negative impacts (Allen, 1998). Because Florida contains the greatest spatial extent of mangroves and greatest research emphasis in the U.S., it is the focus here (Fig. 5). The distribution of mangroves stretches north to Cedar Key on the Gulf Coast and Ponce de Leon Inlet on the Atlantic Coast, both at about 29° 10′ N latitude (Odum et al., 1982). Northward expansion is occurring as a result of decreasing frequency of freezes (Doughty et al., 2016). Three species, black mangrove, red mangrove (Rhizophora mangle), and white mangrove (Laguncularia racemosa) make up the mangrove community, with a fourth, buttonwood (Conocarpus erectus), though not a true mangrove because it displays neither the viviparous reproduction strategies nor specialized root structures of any true mangrove species (Nelson, 1994), making a transition from mangrove swamp to upland forest (Tomlinson, 1986). Most of the area occupied by mangroves lies within Everglades National Park, which borders on Florida Bay and the Gulf of Mexico. Much of the remaining mangrove area lies within land owned by Federal, State and county governments, or by non-profit organizations such as the National Audubon Society. Although mangroves are now protected by law in some parts of the 76

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

continue to progressively move inland as sea levels rise, to areas where suitable conditions occur (Ellison, 2000). Rising global temperature may have little effect on areas already occupied by mangroves in the tropics, but could allow them to migrate and colonize farther poleward. Increasing carbon dioxide and nitrogen enrichment can augment the ability of Spartina to suppress growth of mangrove seedlings, and thus change the competitive relationship between the vegetation types (McKee and Rooth, 2008; Zhang et al., 2012b). Snedaker and Araujo (1998) have shown that increasing carbon dioxide concentrations can alter the competitiveness of mangroves, particularly of Laguncularia racemosa. These threats pose challenges for the future management and conservation of mangroves. As some examples below illustrate, current approaches may not be adequate for those purposes and even more challenging in changing environments.

United States, a number of threats remain. Some threats are a legacy of clear-cutting for human development, as has occurred in Florida's southerly island chain, in the Upper Florida Keys. Mangrove habitat was reduced and fragmented through dredging and filling for residential canals (Kruczynski and McManus, 2002), which increases vulnerability to further destruction or invasion by exotic plants (Strong and Bancroft, 1994). In Florida's vast Everglades wetland, a primary threat has been the altered freshwater flows into the mangrove estuaries, increasing salinity in some locations. Although mangroves can tolerate high salinity, it is known to have a negative impact on seedlings (Koch and Snedaker, 1997), and some instances of mangrove die-off in Florida Bay may be due to salinity outside the range of tolerance (McIvor et al., 1994). Black mangroves are vulnerable to changes in tidal fluxes due to the type of marsh impoundment used for mosquito control, as overflooding or hypersaline conditions can occur (Rey et al., 1990). Hurricanes are a natural environmental disturbance in southern Florida, so mangroves are adapted to their periodic occurrence. However, the amount of damage from a major hurricane can be great – thousands of hectares of mangrove forest were reported to suffer catastrophic disturbance from Hurricane Andrew in 1992 (Doyle et al., 1995) and Hurricane Wilma in 2005 (Smith et al., 2009). What is serious is the finding that repeated heavy disturbances have turned some former mangroves into mudflats, which show no sign of returning to mangroves (Smith et al., 2009). Another constant threat is the possibility of a large oil spill, as the Gulf of Mexico is a site of a major petroleum industry. Duke et al. (1997) in a study of an oil spill from a land tank in Bahia Las Minas, Panama, found that 69 ha of mangroves, or 6% of those in the bay, were killed, and a further 34% suffered damage. Invasive species, particularly Brazilian pepper (Schinus terebinthifolius) and colubrine (Colubrina asiatica), which have invaded some mangrove areas (Davis et al., 2005), are a concern. Pollutants, herbicides, and other run-off constituents from agricultural and urban areas also pose risks, but sea level rise, discussed below, may be a greater future threat.

4. Failures of current conservation approaches Successful management, conservation, and restoration require the commitment of local, State and national level government as well as local communities. As patterns of human settlement around the world continue, people are increasingly distanced from nature and therefore may be less concerned about nature conservation (Miller, 2005; Zaradic et al., 2009). Additionally, as with many conservation programs, benefits from mangroves might be indirect or poorly understood by local residents or they may perceive that they are being excluded from access to previously utilized resources (Shackelton et al., 2002). Some specific cases, and suggestions for remedies, are described in this section. 4.1. Science-based approaches In Indonesia, the Segara Anakan Conservation and Development Project (SACDP), funded by the Asia Development Bank (ADB), in cooperation with the government of Indonesia, faced challenges from grassroots communities. The communities felt that the scientific sector did not produce problem-solving solutions, as it was perceived to be oriented towards the wishes of established elite communities, which led to social opposition before the implementation of the mangrove conservation project. As a result, all solutions were compromised, and science achieved little (Dharmawan et al., 2016). Hence, conservation efforts need to use research to find better ways to integrate with community knowledge (Dharmawan et al., 2016). In Vietnam, the science-based approaches and the local knowledgebased approaches have been separately designed to manage mangrove dominated muddy coasts (MDMCs), both with limited success, due to inadequate integration between the two distinct approaches. Mechanisms are needed to promote a high level of integration of local and scientific knowledge, to effectively manage MDMCs in a sustainable way (Nguyen et al., 2017). The science-based approaches use specialist knowledge, are laboratory based or inventory driven, often beyond the capacity of local communities, leaving little opportunity for the active participation and meaningful consultation of local communities during design, planning and implementing processes (Nguyen and Parnell, 2017). Local knowledge-based approaches have faced two key challenges, namely limited local knowledge and participation, and doubtful sustainability due to financial constraints. In short, active involvement and meaningful consultation between local communities and the science sector is urgently needed for effective implementation of integrated science-community based approaches (Stojanovic et al., 2004).

3. Threats for the future The source of the most serious threats to mangroves is increasing human population density. Human populations and urban areas are concentrated on coastlines, displacing native vegetation. As described in the previous section, conversion of mangrove habitat to agriculture and aquaculture is a major factor in mangrove loss. Other direct effects are mining and the overexploitation of timber, including clearcutting. Indirect effects include factors such as changes in freshwater or tidal flow, pollution from oil exploration, and runoff from solid waste. Disease and pest impacts may be furthered by some of these humanrelated activities (Kathiresan, 2002). Hurricanes and cyclones cause periodic heavy damage (Doyle et al., 1995). Although these storms are natural, cumulative impacts can lead to habitat change (Smith et al., 2009). Tsunamis and their associated earthquakes have also caused long term change (Roy and Krishnan, 2005). 3.1. Climate change Current projections of climate change and sea level rise (SLR) indicate that these could have multiple and varying impacts on mangroves throughout the world (Ward et al., 2016). Because of their landscape position in the intertidal zone, mangroves are directly affected by SLR, but the effects will depend on local topography, slope, the rate of SLR, sources and amount of sediment, and extent of area for landward migration (Woodroffe, 1990; Gilman et al., 2008). Vertical sediment accumulation in mangrove root systems may allow mangroves to keep up with the rate of SLR in areas of higher elevation and those with relatively low tidal range, whereas areas of lower elevation and those with greater tidal range may not be able to keep pace with SLR (Ellison, 2000; Ward et al., 2016). Where possible, mangroves will

4.2. Lack of integration Globally, current management and policy efforts have not been fully successful in ensuring the conservation and sustainable use of mangrove resources, for myriad reasons, including the failure to integrate the differing spatial and temporal scales at which the mangrove 77

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

forests, such as protection of coastal development from storms and surges that damage property and cause death and injury, as well as buffering climate change impacts induced by sea level rise, saltwater intrusion and coastal erosion. Valuation of ecological services has increasingly been developed and utilized in conservation management and policy decisions. The promotion of mangrove conservation and the enhancement of human well-being and livelihoods at the same time have been the two primary aspirations of the United Nations Sustainable Development Goals agenda (United Nations, 2015). These two apparently conflicting aspirations can be met by innovations in ecofarming within mangrove forests to achieve harmony between humans' wealth and mangrove health. Consistent with the Millennium Ecosystem Assessment concept (MA, 2005), ecosystem services may be defined broadly as the wellbeing provided to humans by natural ecosystems. Ecosystem services must therefore be linked with human well-being and social-economic values, a process known as Ecosystem Service Economic Valuation (ESEV). The development of ESEV approaches has been fuelled by the growing need to deal with ecosystem degradation globally, and valuation studies have been advocated to support decision-making and management of ecosystems. ESEV provides useful information about the social-economic benefits and costs associated with alternative coastal policies, facilitating the assessment of trade-offs and synergies inherent in ecosystem-based management. To inform decision making, ESEV can be used to connect science and community engagement into effective policy. Translating good science and strong community engagement into effective policy can be difficult, as scientists, communities, and decision makers often operate within different time frames, in diverse areas of expertise and knowledge, and with differing objectives and incentives (Waite et al., 2015). The science-community-policy gap can be narrowed by improving communication among scientists, decision makers, and other stakeholders through capacity building, outreach, and engagement. We suggest that scientific research would likely be used in management decisions if it explicitly responds to the needs of decision makers, and collected valuation data are targeted at specific policy issues. Major challenges faced by ESEV in developing countries stem from the lack of data, lack of funding, and lack of institutional trust (Torres and Hanley, 2017). ESEV can be used to identify who gets the benefits, and who faces the costs, particularly across the social-economic divide. Estimation of non-use values should be transparent and performed with collaboration among social, natural, and political scientists to build trust and to reduce conflicts of interest (Torres and Hanley, 2017). The local users' complex perceptions of landscape, their holistic sense of well-being, and their context specific socio-cultural valuation of mangrove ESEV beyond the monetary value are indispensable criteria to be incorporated into conservation policies (Queiroz et al., 2017). A good understanding of the complex interrelationships between social and natural systems and of the multiple dimensions and different time scales of ecosystem services is crucial. Such an approach is consistent with the United Nations Sustainable Development Goals of improving human well-being and of promoting the conservation of marine ecosystems (United Nations, 2015). An example of the usefulness of ESEV is the economic valuation of mangrove forests in India, which has shown a significant rise in mangrove cover in the State of Gujarat post-1993 that is attributed to mangrove plantation or regeneration activities in the state (Sahu et al., 2015; FSI, 2011). Mangrove-related fish species have been shown to contribute 10–32% to total marine fisheries catch. The change in fish production due to changes in mangrove cover is examined by comparing fish production in Gujarat to other coastal regions of India, under the Economics of Ecosystems and Biodiversity (TEEB) India initiative. The marginal effect of mangroves on total marine fish output in India as a whole is estimated at 1.86 tonnes per hectare per year, with 23% or INR 68 billion in Gujarat (Anneboina and Kumar, 2017; values are standardized to 2012–2013 prices).

ecosystem services are provided (ecological provisional scale) with the scales at which the management, policy and utilization institutions operate (societal demand scale). For example, local resource users, operating at the demand scale, lack the incentives and institutional imperatives to consider and integrate into the ecological provisional scales of mangrove ecosystems, resulting in a mismatch between benefits and costs. To help deliberation and promote conflict resolution regarding ecosystem services, the Millennium Ecosystem Assessment (MA, 2003, 2005) differentiates between four major service areas, namely (a) supporting, (b) provisioning, (c) regulating, and (d) cultural services. Nevertheless, for mangroves, the large and diverse distributions of stakeholders, less defined systems and functions, overlapping marine and terrestrial areas, with different regulations and jurisdictions, render this integration more difficult. Research conducted in Indonesia and Brazil reported that social opposition has occurred frequently over the failures in managing the conflict between mangrove resource provision and utilization, and over the failure in integrating science with local community knowledge (Máñez et al., 2014). Success of scientific knowledge transfer in conservation projects depends strongly on how successful the science integrates with the local community knowledge base. In Brazil, mangroves are under constant threat by conversion to aquaculture, industry, and urban development among other things, which has destroyed more than 50,000 ha, or about 4% of the total mangrove cover over the past three decades. Restoration efforts have somewhat minimized losses, but only 5% of the total degraded area has recuperated. Around 70% of Brazilian mangroves are today located within preserved areas, making them easier to manage. However, impaired by economic interests and inhibited by the lack of operative conservation policies and best practices, the future of mangrove conservation in Brazil depends on integration of indigenous communities, which depend on mangrove goods and services, with science and other society sectors through integrated science-community based co-management. NGOs, government agencies, academic institutions, and funding agencies can play the role of important agents of action and awareness generation (Datta et al., 2012). For example, abandoned shrimp ponds and degraded forests cause enormous damage to artisanal fishermen, regional fisheries and impair the natural functioning of hydrological and soil integrity. Brazilian shrimp farming could benefit from adapting to utilize natural services provided by mangrove forests and estuaries to produce shrimp in a sustainable way (Ferreira and Lacerda, 2016). An integrated coastal zone management would be beneficial in Brazil and other countries given that these environments are functionally linked through the biogeochemical processes at the continentocean interface (Lundberg and Moberg, 2003; Sheaves, 2009). Legislation in Brazil does not currently integrate buffer habitats such as coral reefs and sea grasses to protect mangroves from human drivers. Brazil's government campaign for a shared co-management of river basins through participation of different social sectors and stakeholders at the “Basin Committees” could be extended to include the coastal zones within their frameworks. As the implementers of laws, the county level of governance suffers from lack of specialists, insufficient funding, and conflicts with other governance levels (Ferreira and Lacerda, 2016). 5. Innovation and success in mangrove conservation Examples can be found throughout the world of success stories in mangrove conservation through innovative solutions that consider the needs of people living alongside mangrove forests. Here we highlight a few of those examples. 5.1. Ecosystem Service Economic Valuation (ESEV) Concern over the loss of mangrove ecosystems often focuses on the disruption or loss in the provision of ecological services by mangrove 78

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

sustainably manage mangroves if they are given sufficient economic incentives, adequate legal rights, and full responsibilities over their allocated mangrove forests. That mangrove conservation and shrimp farming can co-exist in harmony in an environment of economic incentives supported by appropriate legislation, calls for a re-evaluation of the perception that shrimp farming necessitates deforestation and degradation of mangrove habitat (Ha et al., 2012). As income from mangrove timber harvests is very low compared to shrimp harvests, an equitable profit sharing scheme has been devised to ensure that maximizing aquaculture production will not compromise mangroves' functional integrity. While complying with the regulations stipulated by the State regarding forest-to-pond ratio, shrimp farmers need to also devote attention to maintaining the quality and integrity of mangroves under their care. This seemingly conflicting requirement poses a constant challenge to the sustainability of this arrangement (Ha et al., 2012; Bush et al., 2010). A study in the Volta estuary of Ghana embraced the concept of community based co-management of mangrove restoration and management at the local scales in which resource users are the key stakeholders, who play significant roles and responsibilities in maintaining mangrove conservation within their jurisdiction (Aheto et al., 2016). Resource users' livelihoods, food security, economic benefits and wellbeing are the primary motivation to sustainably exploit, restore and manage the resources (Wagner, 2001). Financial motivations can be the basis for sustainable mangrove reforestation and prevention of unsustainable exploitation of mangrove stands in Volta and in other regions. Successes in community-based mangrove management have also been achieved in several countries around the world, especially in South and Southeast Asia, South America, and Eastern and Southern Africa (Datta et al., 2012). This finding is consistent with the observation of Melana et al. (2000) that “people first and sustainable mangrove forest management will follow”. In this context, replanting and restoration communities are not primarily motivated by ecological interests alone but rather in conjunction with compensatory financial rewards. Achieving clarity on ownership and the rights of access to coastal resources could lead to more effective mangrove resource management through local institutional arrangements. Local communities alone cannot typically manage coastal ecosystems for reasons such as limited research capacity, limited area of jurisdiction, budget constraints, and local politics (Sorensen and McCreary, 1990). With objectives clearly established at the outset, comanagement is an approach in which governments can enforce certain authority and share responsibilities with local communities in coastal resource management with resource users, academic institutions, and non-governmental organizations as partners.

In Southeast Asia in general, mangroves are generally undervalued in decision making relating to their use, conservation, and restoration. Brander et al. (2012) constructed a database containing 130 value estimates, for mangrove ESEV in Southeast Asia, standardized to USD per hectare per year in 2007 prices. The mean and median values of ESEV for mangrove ecosystem services are 4185 and 239 US$/ha/year respectively, with high variability across study sites due to vast variations in the bio-physical characteristics of the site and the socio-economic characteristics of the beneficiaries of ecosystem services. A meta-analytic value function is used to estimate the change in ESEV of mangrove ecosystem services in Southeast Asia under a baseline scenario of mangrove loss for the period 2000–2050. The estimated foregone annual benefits in 2050 are US$ 2.2 billion, with a prediction interval of US$ 1.6–2.8 billion. These estimates of mangrove ecosystem services are particularly important to Indonesia, which has the largest stock of mangroves in 2000 but also faces the largest losses of 1.7 million hectares or 38% over the period 2000–2050. The Wider Caribbean Basin (WCB) economy, heavily dependent on tourism, fisheries, and coastal protection, is driven by coastal ecosystem services provided by mangroves and coral reefs. Despite the challenges, coastal ESEV in the WCB has helped justify fishing regulations, establish marine protected areas, award or settle damage claims, and identify sustainable sources of finance for conservation, which work toward long-term viability (Waite et al., 2015). However, the overall economic value of ecosystem goods and services in the WCB remains largely unquantified (Schuhmann and Mahon, 2015). Current ESEV valuation efforts have been piecemeal, fragmented, and largely unconnected to policy needs (Schuhmann and Mahon, 2015). Valuation efforts and supporting data collection on marine ecosystems would benefit from integration across disciplines, institutions, and nations within the WCB, as most marine resources are transboundary and require international collaboration for sustainable use. ESEV can be mainstreamed into regional policy processes such as the Caribbean Large Marine Ecosystem Strategic Action Programme (CLME-SAP) adopted in 2013 by the countries of the WCB (Mahon et al., 2014). 5.2. Inclusion of human needs The United Nations Sustainable Development Goals (UN-SDG) acknowledge the harmonious co-existence of natural ecosystems and humans and call for the concurrent improvement of human well-being and livelihoods while promoting the conservation of marine ecosystems (United Nations, 2015). Efforts have been devoted in many parts of the world to achieving this harmonious co-existence by means of innovation in sustainable eco-farming aquaculture practices within mangrove forests. We briefly present three case studies in Guangxi of China, in Ca Mau of the Mekong Delta, and in the Volta estuary of Ghana, to illustrate the potential of mangrove conservation and restoration facing increasing demands on mangrove resources due to population growth. In Guangxi Province of China, an eco-farming aquaculture system that does not require cutting of mangrove trees or conversion of mangroves has been perfected with no industrial feed input, following field trials between 2007 and 2012 conducted in mangrove areas. This unique innovation succeeded in addressing the conflict between mangrove conservation and economic return of aquaculture (Fan et al., 2013). Using a network of underground tubes and pipes buried in between mangrove roots to augment benthic habitats for fish, this system can bring in mean production of between USD 27,000, and 45,000 per hectare per annum. The environmentally friendly eco-farming site is accessible by boardwalks that facilitate ecotourism and public education, thereby increasing the income of the farmers and promoting UNSDG. The system has been shown to be surge resistant, easy to operate, and has low management cost, while the products are of high quality and high value. Along the Mekong Delta, a study in the Ca Mau province supports the hypothesis that shrimp farmers may be able to plant, protect, and

6. Summary Coastal mangrove forests provide invaluable and irreplaceable services to people and wildlife, making their protection critical. As loss of mangrove habitat continues throughout much of the world, solutions to reverse this downward trend will need to involve commitments from many parties. Policies enacted and enforced by government are one part of that protection, but likely not sufficient in isolation. An examination of studies throughout the world can help guide the implementation of successful conservation and restoration practices. These restoration efforts, when put into practice, would require the buy-in and commitment of local people with the will to conserve these habitats that could otherwise serve personal gain through timber harvest, for example. Citizen science can also be employed as a means to engage people and benefit from their local knowledge. Information and data provided by locals have been used for conservation initiatives, for example protected area planning (e.g., Scholz et al., 2004), natural resource monitoring (e.g., Giordano et al., 2010), and disease threats (e.g., Dhondt et al., 1998). Data collected can be used to assist with monitoring, modeling, and restoration and conservation planning. With 79

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

UNESCO Women in Science Fellowship 2017. SSR and DLD were supported by the US Geological Survey's Greater Everglades Priority Ecosystem Science program.

the engagement of local people living with these resources, we suggest that the current rates of decline can be slowed and ultimately reversed. There remains a paucity of academic literature examining the utilization of ESEV by decision-makers. Overall ESEV is used more for communication and advocacy than for decision-making or for setting up economic and financial instruments (Marre et al., 2015). In many nations, ESEV has not been perceived as critical in the design, adoption, or implementation of policy measures regarding coastal and marine ecosystems (Marre et al., 2015). Ideally, collaborations between researchers and decision-makers would be enhanced to facilitate research and knowledge transfer, as well as to promote uptake and impact within policy contexts. ESEV studies can generate information on the costs associated with species and habitat loss, the benefits of conservation and restoration efforts, and economic dependence on natural ecosystems. Appropriate and timely ESEV of ecological services that contribute to better-informed decision making can benefit the protection, restoration, and development of coastal resources in a sustainable manner. Climate change and SLR will have varying impacts on mangrove habitats throughout the world. In the face of SLR, some regions, such as Florida, will have the advantage of having more room for mangroves to expand inland, whereas in more populated coastal regions without a protected coastal zone, there is more likely to be the problem that humans occupy areas inland, thus potentially restricting inland migration. Higher temperatures might not impact mangroves in more tropical regions such as Malaysia, but moving away from the equator may increase the likelihood that warming temperatures will promote poleward expansion. Proactive engagement with governments and the public in these potential regions of mangrove expansion may help with conservation efforts. Identifying and implementing approaches to the conservation and restoration of mangrove habitats that can be applied across the globe may accelerate learning and protection efforts. Here we provide insights from many countries around the world on various successes and failures in mangrove conservation and restoration. These insights can provide a platform to identify successful solutions. Such global learning and action may secure the future of mangrove forests and the services they provide worldwide.

References Aheto, D.W., Kankam, S., Okyere, I., Mensah, E., Osman, A., Jonah, F.E., Mensah, J.C., 2016. Community-based mangrove forest management: implications for local livelihoods and coastal resource conservation along the Volta estuary catchment area of Ghana. Ocean Coast. Manag. 127, 43–54. Allen, J., 1998. Mangroves as alien species: the case of Hawaii. Glob. Ecol. Biogeogr. Lett. 7, 61–71. Alongi, D.M., 2002. Present state and future of world's mangrove forests. Environ. Conserv. 29, 331–349. Anneboina, L.R., Kumar, K.S.K., 2017. Economic analysis of mangrove and marine fishery linkages in India. Ecosyst. Serv 24, 114–123. Armitage, A.R., Highfield, W.E., Brody, S.D., Louchouarn, L., 2015. The contribution of mangrove expansion to salt marsh loss on the Texas Gulf Coast. PLoS One 10, e0125404. Barbier, E.B., 2016. The protective service of mangrove ecosystems: a review of valuation methods. Mar. Pollut. Bull. 109 (2), 676–681. Barbier, E.B., Koch, E.W., Silliman, B.R., Hacker, S.D., Wolanski, E., Primavera, J., Granek, E.F., Polasky, S., Aswani, S., Cramer, L.A., Stoms, D.M., 2008. Coastal ecosystem-based management with nonlinear ecological functions and values. Science 319, 321–323. Berkes, F., 2004. Rethinking community-based conservation. Conserv. Biol. 18, 621–630. Brander, L.M., Wagtendonk, A.J., Hussain, S.S., McVittie, A., Verburg, P.H., Groot, R.S., van der Ploeg, S., 2012. Ecosystem service values for mangroves in Southeast Asia: a meta-analysis and value transfer application. Ecosyst. Serv. 1, 62–69. Bush, S.R., van Zwieten, P.A.M., Visser, L., van Dijk, H., Bosma, R., de Boer, W.F., Verdegem, M., 2010. Scenarios for resilient shrimp aquaculture in tropical coastal areas. Ecol. Soc. 15 (2), 15. Chen, L.Z., Wang, W.Q., Zhang, Y.H., Lin, G.H., 2009. Recent progresses in mangrove conservation, restoration and research in China. Plant Ecol. 2, 45–54. Datta, D., Chattopadhyay, R.N., Guha, P., 2012. Community based mangrove management: a review on status and sustainability. J. Environ. Manag. 107, 84–95. Davis, S.M., Childers, D.L., Lorenz, J.J., Wanless, H.R., Hopkins, T.E., 2005. A conceptual model of ecological interactions in the mangrove estuaries of the Florida Everglades. Wetlands 25, 832–842. Dharmawan, B., Böcher, M., Krott, M., 2016. The failure of the mangrove conservation plan in Indonesia: weak research and an ignorance of grassroots politics. Ocean Coast. Manag. 130, 250–259. Dhondt, A.A., Tessaglia, D.L., Slothower, R.L., 1998. Epidemic mycoplasmal conjunctivitis in house finches from eastern North America. J. Wildl. Dis. 34 (2), 265–280. Doughty, C.L., Langley, J.A., Walker, W.S., Feller, I.C., Schaub, R., Chapman, S.K., 2016. Mangrove range expansion rapidly increases coastal wetland carbon storage. Estuar. Coasts 39, 385–396. Doyle, T.W., Smith III, T.J., Robblee, M.B., 1995. Wind damage effects of Hurricane Andrew on mangrove communities along the southwest coast of Florida, USA. J. Coast. Res. 21, 159–168. Duke, N.C., Pinzon, Z.S., Prada, M.C., 1997. Large-scale damage to mangrove forests following two large oil spills in Panama. Biotropica 29, 2–14. Ellison, J.C., 2000. How South Pacific mangroves may respond to predicted climate change and sea-level rise. In: Gillespie, A., Burns, W.C.G. (Eds.), Climate Change in the South Pacific: Impacts and Responses in Australia, New Zealand, and Small Island States. Springer Netherlands, pp. 289–300. Ewel, K.C., Twilley, R.R., Ong, J.-E., 1998. Different kinds of mangrove forests provide different goods and services. Glob. Ecol. Biogeogr. Lett. 7, 83–94. Fan, H., He, B., Pernetta, J.C., 2013. Mangrove ecofarming in Guangxi Province China: an innovative approach to sustainable mangrove use. Ocean Coast. Manag. 85, 201–208. Fan, H.Q., Liu, W.A., Zhong, C.R., Ni, X., 2014. Analytic study on the damages of woodboring isopod, Sphaeroma, to China mangroves. Guangxi Sci. 21 (2), 140–146 152. Ferreira, A.C., Lacerda, L.D., 2016. Degradation and conservation of Brazilian mangroves, status and perspectives. Ocean Coast. Manag. 125, 38–46. FSI, 2011. India State of Forest Report 1987–2011. Forest Survey of India, Ministry of Environment and Forests, Government of India. Gilman, E.L., Ellison, J., Duke, N.C., Field, C., 2008. Threats to mangroves from climate change and adaptation options: a review. Aquat. Bot. 89, 237–250. Giordano, R., Liersch, S., Vurro, M., Hirsch, D., 2010. Integrating local and technical knowledge to support soil salinity monitoring in the Amudarya river basin. J. Environ. Manag. 91, 1718–1729. Giri, C., Ochieng, E., Tieszin, L.L., Zhu, Z., Singh, A., Loveland, T., Masek, J., Duke, N., 2011. Status and distribution of mangrove forests of the world using earth observation satellite data. Glob. Ecol. Biogeogr. 20, 154–159. Ha, T.T.T., van Dijk, H., Bush, S.R., 2012. Mangrove conservation or shrimp farmer's livelihood? The devolution of forest management and benefit sharing in the Mekong Delta, Vietnam. Ocean Coast. Manag. 69, 185–193. Hamdan, O., Khali Aziz, H., Shamsudin, I., 2010. Kajian Perubahan Hutan Paya Laut Negeri Selangor, Kedah dan Kelantan (Study on the Changes of Mangrove Forest in Selangor, Kedah and Kelantan). Reports No. 91. Forest Research Institute Malaysia (FRIM). https://info.frim.gov.my/infocenter/Korporat/2003Publications/Links/ FRIM11.htm. Hamdan, O., Khali Aziz, H., Shamsudin, I., Raja Barizan, R.S., 2012. Status of Mangrove

Author contributions SSR, DLD, KHL and YL conceived of the review. All authors contributed to writing. Disclaimer This draft manuscript is distributed solely for purposes of courtesy review and comments received will be addressed and treated as appropriate to ensure there is no conflict of interest. Its content is deliberative and predecisional, so it must not be disclosed or released by reviewers. Because the manuscript has not yet been approved for publication by the U.S. Geological Survey (USGS), it does not represent any official USGS finding or policy. Acknowledgments We thank T. Doyle, S. Haider, and three anonymous reviewers for providing helpful comments on this review, and A. Benscoter for editorial and organizational assistance. Any use of trade, firm, or product names is for descriptive purposes and does not imply endorsement by the U.S. Government. TSY and KHL gratefully acknowledge the financial support by FRGS Grant 203/PMATHS/6711569 and the information provided by Wetlands International Malaysia. KHL is grateful to the Jeffrey Sachs Center on Sustainable Development of the Sunway University for providing a conducive environment to pursue research on sustainable development. TSY gratefully acknowledges the L'Oréal80

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

climate extremes. Ecosphere 6, 1–15. Pelegri, S.P., Twilley, R.R., 1998. Heterotrophic nitrogen fixation (acetylene reduction) during leaf-litter decomposition of two mangrove species from south Florida, USA. Mar. Biol. 131, 53–61. Queiroz, L.S., Rossi, S., Calvet-Mir, L., Ruiz-Mallén, I., García-Betorz, S., Salvà-Prat, J., Meireles, A.J.A., 2017. Neglected ecosystem services: highlighting the socio-cultural perception of mangroves in decision-making processes. Ecosyst. Serv 26, 137–145. Ren, H., Lu, H., Shen, W., Huang, C., Guo, Q., Li, Z.A., Jian, S., 2009. Sonneratia apetala Buch. Ham in the mangrove ecosystems of China: an invasive species or restoration species? Ecol. Eng. 35 (8), 1243–1248. Rey, J.R., Crossman, R.A., Kain, T.R., 1990. Vegetation dynamics in impounded marshes along the Indian River lagoon, Florida, USA. Environ. Manag. 14, 397–409. Richards, D.R., Friess, D.A., 2016. Rates and drivers of mangrove deforestation in Southeast Asia, 2000–2012. Proc. Natl. Acad. Sci. 113 (2), 344–349. Roy, S.D., Krishnan, P., 2005. Mangrove stands of Andamans vis-à-vis tsunami. Curr. Sci. 89, 1800–1804. Sabah Biodiversity Centre, 2011. Lower Kinabatangan-Segama Wetlands Ramsar Site Management Plan, vol. I Sabah State Government, Malaysia 978–983–41084–6–5, 265 pp. Sahu, S.C., Suresh, H.S., Murthy, I.K., Ravindranath, N.H., 2015. Mangrove area assessment in India: implications of loss of mangroves. J. Earth Sci. Clim. Change 6 (5), 280. Saintilan, N., Wilson, N., Rogers, K., Rajkaran, A., Krauss, K.W., 2014. Mangrove expansion and salt marsh decline at mangrove poleward limits. Glob. Change Biol. 20 (1), 147–157. Scholz, A., Bonzon, K., Fujita, R., Benjamin, N., Woodling, N., Black, P., Steinback, C., 2004. Participatory socioeconomic analysis: drawing on fishermen's knowledge for marine protected area planning in California. Mar. Pol. 28 (4), 335–349. Schuhmann, P.W., Mahon, R., 2015. The valuation of marine ecosystem goods and services in the Caribbean: a literature review and framework for future valuation efforts. Ecosyst. Serv. 11, 56–66. Shackelton, S., Campbell, B., Wollenberg, E., Edmunds, D., 2002. Devolution and Community-based Natural Resource Management: Creating Space for Local People to Participate and Benefit? Overseas Development Institute, London, United Kingdom. Sheaves, M., 2009. Consequences of ecological connectivity: the coastal ecosystem mosaic. Mar. Ecol. Prog. Ser. 391, 107–115. Smith III, T.J., Anderson, G.H., Balentine, K., Tiling, G., Ward, G.A., Whelan, K.R.T., 2009. Cumulative impacts of hurricanes on Florida mangrove ecosystems: sediment deposition, storm surges, and vegetation. Wetlands 29, 24–34. Snedaker, S.C., Araujo, R.J., 1998. Stomatal conductance and gas exchange in four species of Caribbean mangroves exposed to ambient and increased CO2. Mar. Freshw. Res. 49, 325–327. Sorensen, J., McCreary, S., 1990. Institutional arrangements for managing coastal resources and environments. In: COAST, Renewable Resources Information Series. National Park Service, US Department of the Interior and USAID, second ed. Coastal Management Publication No. 1. Spalding, M., Blasco, F., Field, C., 1997. World Mangrove Atlas. The International Society for Mangrove Ecosystems. Okinawa, Japan. . Stojanovic, T., Ballinger, R.C., Lalwani, C.S., 2004. Successful integrated coastal management: measuring it with research and contributing to wise practice. Ocean Coast. Manag. 47, 273–298. Strong, A.M., Bancroft, G.T., 1994. Patterns of deforestation and fragmentation of mangrove and deciduous seasonal forests in the Upper Florida Keys. Bull. Mar. Sci. 54, 795–804. Teh, S.Y., Koh, H.L., Liu, P.L.-F., IIzani, A.M.I., Lee, H.L., 2009. Analytical and numerical simulation of tsunami mitigation by mangroves in Penang, Malaysia. J. Asian Earth Sci. 36 (1), 38–46. Tomlinson, P.B., 1986. The Botany of Mangroves. Cambridge University Press, New York, New York, USA. Torres, C., Hanley, N., 2017. Communicating research on the economic valuation of coastal and marine ecosystem services. Mar. Pol. 75, 99–107. Twilley, R.R., 1998. Mangrove wetlands. In: Messina, M.G., Conner, W.H. (Eds.), Southern Forested Wetlands: Ecology and Management. Lewis Publishers, Boca Raton, Florida, USA, pp. 445–473. United Nations (UN), 2015. Transforming Our World: the 2030 Agenda for Sustainable Development, vol. 21 United Nations General Assembly October 2015, A/RES/70/1, available at: http://www.refworld.org/docid/57b6e3e44.html, Accessed date: 1 November 2017. Valiela, I., Bowen, J.L., York, J.K., 2001. Mangrove forests: one of the world's threatened major tropical environments. BioScience 51, 807–815. Wagner, F.H., 2001. Freeing agency research from policy pressures: a need and an approach. Bioscience 51, 445–450. Waite, R., Kushner, B., Jungwiwattanaporn, M., Gray, E., Burke, L., 2015. Use of coastal economic valuation in decision making in the Caribbean: enabling conditions and lessons learned. Ecosyst. Serv. 11, 45–55. Wang, W.Q., 2007. Chinese Mangrove. Science Press, Beijing, China. Wang, L., Mu, M., Li, X., Lin, P., Wang, W., 2011. Differentiation between true mangroves and mangrove associates based on leaf traits and salt contents. J. Plant Ecol. 4, 292–301. Ward, R.D., Friess, D.A., Day, R.H., MacKenzie, R.A., 2016. Impacts of climate change on mangrove ecosystems: a region by region overview. Ecosys. Health Sustain. 2 (4), e01211. Wolanski, E., 2007. Thematic paper: synthesis of the protective functions of coastal forests and trees against natural hazards. In: Coastal Protection in the Aftermath of the Indian Ocean Tsunami: what Role for Forests and Trees. RAP Publication (FAO), pp. 157–159.

in Peninsular Malaysia. Forest Research Institute Malaysia (FRIM), Kepong, Selangor Darul Ehsan, Malaysia. Hamilton, S.E., Casey, D., 2016. Creation of a high spatio-temporal resolution global database of continuous mangrove forest cover for the 21st century (CGMFC-21). Glob. Ecol. Biogeogr. 25 (6), 729–738. He, Y., Zhang, M.-X., 2001. Study on wetland loss and its reasons in China. Chin. Geogr. Sci. 11, 241–245. Kathiresan, K., 2002. Why are mangroves degrading? Curr. Sci. 83, 1246–1249. Kathiresan, K., Rajendran, N., 2005. Coastal mangrove forests mitigated tsunami. Estuar. Coast. Shelf Sci. 65, 601–606. Kimball, M., Teas, H.J., 1975. Nitrogen fixation in mangrove areas of South Florida. In: In: Walsh, G.E., Snedaker, S.C., Teas, H.J. (Eds.), Proceedings of the International Symposium on Biology and Management of Mangroves, vol. 2. University of Florida, Gainesville, USA, pp. 654–661. Koch, M.S., Snedaker, S.C., 1997. Factors influencing Rhizophora mangle L. seedling development in Everglades carbonate soils. Aquat. Bot. 59, 87–98. Kruczynski, W.L., McManus, F., 2002. Water quality concerns in the Florida Keys: sources, effects, and solutions. In: Porter, J.W., Porter, K.G. (Eds.), The Everglades, Florida Bay, and Coral Reefs of the Florida Keys: an Ecosystem Sourcebook. CRC Press, Boca Raton, Florida, USA, pp. 827–881. Laegdsgaard, P., Johnson, C., 2001. Why do juvenile fish utilize mangrove habitats? J. Exp. Mar. Biol. Ecol. 257, 229–253. Li, Y.H., 2012a. Ecology and Conservation of Estuarine Wetland in Quanzhou Bay. Environmental Science Press, Beijing, China. Li, Y.H., 2012b. Effect and countermeasure of the global climate change on the mangrove eco-system in Quanzhou Bay estuary. Strat. Sci. 2, 10–12. Li, M.S., Lee, S.Y., 1997. Mangroves in China: a brief review. For. Ecol. Manag. 96, 241–259. Liu, H., Zhang, K., Li, Y., Xie, L., 2013. Numerical study of the sensitivity of mangroves in reducing storm surge and flooding to hurricane characteristics in southern Florida. Cont. Shelf Res. 64, 51–65. Lundberg, J., Moberg, F., 2003. Mobile link organisms and ecosystem functioning: implications for ecosystem resilience and management. Ecosystems 6, 87–98. Mahon, R., Fanning, L., McConney, P., 2014. Assessing and facilitating emerging regional ocean governance arrangements in the Wider Caribbean Region. Ocean Yearb. 28, 631–671. Máñez, K.S., Krause, G., Ring, I., Glaser, M., 2014. The Gordian knot of mangrove conservation: disentangling the role of scale, services and benefits. Glob. Environ. Change 28, 120–128. Marre, J., Thebaud, O., Pascoe, S., Jennings, S., Boncoeur, J., Coglan, L., 2015. The use of ecosystem services valuation in Australian coastal zone management. Mar. Pol. 56, 117–124. McIvor, C.C., Ley, J.A., Bjork, R.D., 1994. Changes in freshwater inflow from the Everglades to Florida Bay including effects on biota and biotic processes: a review. In: Davis, S.M., Ogden, J.C. (Eds.), Everglades: the Ecosystem and its Restoration. St. Lucie Press, Delray Beach, Florida, USA, pp. 117–146. McKee, K.L., Rooth, J.E., 2008. Where temperate meets tropical: multi-factorial effects of elevated CO2, nitrogen enrichment, and competition on a mangrove-salt marsh community. Glob. Change Biol. 14, 971–984. McLeod, E., Chmura, G., Bouillon, S., Salm, R., Bjork, M., Duarte, C.M., Lovelock, C.E., Schlesinger, W.H., Silliman, B.R., 2011. A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats is sequestering CO2. Front. Ecol. Environ. 9, 552–560. Melana, D.M., Atchue III, J., Yao, C.E., Edwards, R., Melana, E.E., Gonzales, H.I., 2000. Mangrove Management Handbook. Department of Environment and Natural Resources, Manila, Philippines Through the Coastal Resource Management Project, Cebu City, Philippines. Michot, T.C., Day, R.H., Wells, C.J., 2010. Increase in Black Mangrove Abundance in Coastal Louisiana. Louisiana Natural Resource News. Newsl. Louisiana Assoc. Prof. Biol. January, 4–5. . Millennium Ecosystem Assessment (MA), 2003. Ecosystems and Human Well-Being: a Framework for Assessment. Island Press, Washington, DC, USA. Millennium Ecosystem Assessment (MA), 2005. Ecosystems and Human Well-Being: Synthesis. Island Press, Washington, DC, USA. Miller, J.R., 2005. Biodiversity conservation and the extinction of experience. Trends Ecol. Evol. 20 (8), 430–434. Nagelkerken, I., van der Velde, G., Gorissen, M.W., Meijer, G.J., Van, t Hof, T., den Hartog, C., 2000. Importance of mangroves, seagrass beds and the shallow reef as a nursery for important coral reef fishes, using a visual census technique. Estuar. Coast. Shelf Sci. 51, 31–44. Nelson, G., 1994. The Trees of Florida: a Reference and Field Guide (Reference and Field Guides). Pineapple Press, Saratosa, Florida, USA. Nguyen, T.P., Luom, T.T., Parnell, K.E., 2017. Existing strategies for managing mangrove dominated muddy coasts: knowledge gaps and recommendations. Ocean Coast. Manag. 138, 93–100. Nguyen, T.P., Parnell, K.E., 2017. Gradual expansion of mangrove areas as an ecological solution for stabilizing a severely eroded mangrove dominated muddy coast. Ecol. Eng. 107, 239–243. Odum, W.E., McIvor, C.C., Smith III, T.J., 1982. The Ecology of the Mangroves of South Florida: a Community Profile. United States Fish and Wildlife Service, Washington, DC, USA FWS/OS–81/24. Osland, M.J., Enwright, N., Day, R.H., Doyle, T.W., 2013. Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States. Glob. Change Biol. 19 (5), 1482–1494. Osland, M.J., Day, R.H., From, A.S., McLemore, M.L., McCoy, J., Kelleway, J., 2015. Life stage influences the resistance and resilience of black mangrove forests to winter

81

Ocean and Coastal Management 154 (2018) 72–82

S.S. Romañach et al.

Zhang, K., Liu, H., Li, Y., Xu, H., Shen, J., Rhome, J., Smith III, T.J., 2012a. The role of mangroves in attenuating storm surges. Estuar. Coast. Shelf Sci. 102–103, 11–23. Zhang, Y., Huang, G., Wang, W., Chen, L., Lin, G., 2012b. Interactions between mangroves and exotic Spartina in an anthropogenically-disturbed estuary in southern China. Ecology 93, 588–597. Zuang, X.L., Lin, J., Li, Y.H., 2011. The present situation and the major control measures of mangroves in southeast of China. Straits Sci. 7 19–2.

Wolanski, E., Spagnol, S., Thomas, S., Moore, K., Alongi, D.M., Trott, L., Davidson, A., 2000. Modelling and visualizing the fate of shrimp pond effluent in a mangrovefringed tidal creek. Estuar. Coast. Shelf Sci. 50, 85–97. Woodroffe, C.D., 1990. The impact of sea-level rise on mangrove shorelines. Prog. Phys. Geogr. 14, 483–520. Zaradic, P.A., Pergams, O.R., Kareiva, P., 2009. The impact of nature experience on willingness to support conservation. PLoS One 4 (10), e7367.

82