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In the Front Line - Shoreline Protection and Other Ecosystem Services from Mangroves and Coral Reefs

UNEP Publication (2006)
         In the front line

Shoreline protection and other ecosystem services
          from mangroves and coral reefs
         In the front line

Shoreline protection and other ecosystem services
          from mangroves and coral reefs
In the front line

UNEP World Conservation Monitoring Centre                     ACKNOWLEDGEMENTS
219 Huntingdon Road,                                We gratefully acknowledge the many partners and
Cambridge CB3 0DL,                                 institutions who contributed to this publication, in
United Kingdom                                   particular the following individuals who provided
Tel: +44 (0) 1223 277314                              information and comments on early drafts: John Agard,
Fax: +44 (0) 1223 277136                              Tundi Agardy, Jackie Alder, Daniel Alongi, Andrew Baird,
Email:                             Nicola Barnard, Juan Bezaury, Simon Blyth, Barbara
Website:                             Brown, Marion Cheatle, Isabelle Côté, Salif Diop, Alasdair
                                          Edwards, Norberto Fernandez, Harinda Fernando, Phil
THE UNITED NATIONS ENVIRONMENT PROGRAMME WORLD                   Fox, Alison Glass, Stefan Hain, Mark Huxham, Val Kapos,
CONSERVATION MONITORING CENTRE (UNEP-WCMC) is the                 Carmen Lacambra, Ian May, Nick Nuttal, Pascal Peduzzi,
biodiversity assessment and policy implementation arm of              Pasi Rinne, Toby Roxburgh, Charles Sheppard, Jerker
the United Nations Environment Programme (UNEP), the                Tamelander, Kristian Teleki, Ruben Torres, Collette
world’s foremost intergovernmental environmental                  Wabnitz, Alan White, Victoria Wood and Kaveh Zahedi.
organization. The Centre has been in operation for over 25
years, combining scientific research with practical policy

UNEP-WCMC provides objective, scientifically rigorous
products and services to help decision makers recognize
the value of biodiversity and apply this knowledge to all
that they do. Its core business is managing data about
ecosystems and biodiversity, interpreting and analysing
that data to provide assessments and policy analysis, and
making the results available to national and international
decision makers and businesses.

Lead Author: Sue Wells
Contributing authors: Corinna Ravilious and
Emily Corcoran

Front cover photos: Y Yusuf; UNEP/Topham;
E Clua/CRISP, 2005; S Wells; UNEP-WCMC World
Atlas of Coral Reefs.
Back cover photo: S Wells

Citation: UNEP-WCMC (2006) In the front line: shoreline
protection and other ecosystem services from mangroves
and coral reefs. UNEP-WCMC, Cambridge, UK 33 pp


A Banson production
Printed in the UK by Cambridge Printers

The contents of this report do not necessarily reflect the views or policies of the United Nations Environment Programme, the UNEP World Conservation
Monitoring Centre, the International Coral Reef Action Network or IUCN–The World Conservation Union. The designations employed and the presentations
do not imply the expressions of any opinion whatsoever on the part of these organizations concerning the legal status of any country, territory, city or area
or its authority, or concerning the delimitation of its frontiers or boundaries.

                                                                                    In the front line

Introduction...........................................................................................................................................................................  4

Key messages.......................................................................................................................................................................    5

Global status of reefs and mangroves..................................................................................................................................           7
       Distribution......................................................................................................................................................      7
       Status...............................................................................................................................................................     7
       Threats.............................................................................................................................................................     9

Value of ecosystem services................................................................................................................................................. 12

Regulating services – shoreline protection.......................................................................................................................... 14
       Wind-generated waves and storms................................................................................................................ 15
       Tsunamis......................................................................................................................................................... 16

Other ecosystem services..................................................................................................................................................... 18
       Other regulating services................................................................................................................................ 18
           Climate and global carbon cycle...................................................................................................... 18
           Water quality..................................................................................................................................... 18
       Cultural services.............................................................................................................................................. 18
           Tourism............................................................................................................................................. 18
       Provisioning services....................................................................................................................................... 19
           Fisheries and other marine products.............................................................................................. 19
           Mangrove forest products................................................................................................................ 20
           Pharmaceuticals.............................................................................................................................. 20
       Supporting services......................................................................................................................................... 20

What happens when ecosystem services are lost?..............................................................................................................               21
      Loss of regulating services.............................................................................................................................            21
      Loss of provisioning services..........................................................................................................................            22
      Loss of cultural services.................................................................................................................................           22

Natural recovery – or rehabilitation and restoration?.......................................................................................................... 23
       Coral reefs....................................................................................................................................................... 24
       Mangroves........................................................................................................................................................ 25

Mangroves and coral reefs on tropical coastlines of the future..........................................................................................                 26
      Maintaining regulating services......................................................................................................................             26
      Maintaining provisioning services...................................................................................................................             26
      Maintaining cultural services..........................................................................................................................            27
      Essential management tools..........................................................................................................................             27
           Integrated coastal management.....................................................................................................                  28
           Marine protected areas....................................................................................................................              28
           Improved resilience and adaptive management.............................................................................                       29
      Financing the future........................................................................................................................................         29

References............................................................................................................................................................................. 31

           In the front line

           The Indian Ocean tsunami of 26 December 2004 and its      hurricanes and typhoons, and other potential consequences
           tragic and devastating consequences were a wake-up call    of global warming. More than ever, it is essential to consider
           for the global community, dramatically drawing attention to  the full value of ‘ecosystem services’ (the benefits that
           the vulnerability of tropical coastal ecosystems and the    people obtain from ecosystems) when making decisions
           dangers of undermining the services they provide to      about coastal development.
           humankind. This was further emphasized by the             The aim of this publication is to help decision
           catastrophic hurricane season in the Gulf of Mexico in     makers and policy makers around the world understand the
           2005 when Hurricanes Katrina, Rita and Wilma caused      importance of coastal habitats to humans, using coral reefs
           much publicized and extensive damage to coastal areas.     and mangroves as an example. It looks at the role of these
           The numerous other tropical storms that affected coastal    ecosystems in protecting the coast, and takes into account
           communities and ecosystems in other parts of the world     new studies of this complex topic triggered by the tsunami
           in the same year received much less attention, but were    and tropical storms. The publication also addresses the
           also notable.                         huge range of other benefits provided by these ecosystems
                The lessons learnt in terms of loss of life, damage  and the role that they can play in coastal development and
           sustained, and approaches to reconstruction and mitigation   in restoring and maintaining the livelihoods of those who
           are critically relevant to future management of the coast in  have suffered from extreme events, whether natural or
           a context of increasing severe weather events such as     induced by human activity.
NASA/Still Pictures

                                                    In the front line

Key messages
GLOBAL STATUS OF CORAL REEFS AND MANGROVES          Ecosystems that can no longer provide their full ecological
Coral reefs and mangroves are two of the world’s rarest   services have a social and economic ‘cost’ that can be felt
ecosystems, covering an area that is an order of magnitude  locally and many miles away. Degradation of coral reefs and
less than that of tropical and subtropical forests. Both   mangroves may, and in some cases already does, cause:
                                 ❏ Reduced fish catches and tourism revenue in
ecosystems are under serious threat.
  ❏ Some 30 per cent of reefs are already seriously        coastal communities, and potentially even loss
   damaged and 60 per cent could be lost by 2030.        of food security and malnutrition due to lack
   Threats include overfishing, use of destructive        of protein.
                                 ❏ Loss of export earnings and decline of the
   fishing methods, coral mining, pollution, sedi-
   mentation, anchor damage and tourism, as well         tourism industry.
                                 ❏ Increased coastal erosion and destruction from
   as coral bleaching, disease and tropical storms.
   This combination of impacts is causing a shift, on      storms and catastrophic natural events, which
   many reefs, from a coral-dominated ecosystem to        affects coastal residents, tourism operations and
   one dominated by algae.                    many other economic sectors.
  ❏ An estimated 35 per cent of the world’s original
   mangrove cover has already gone, with some       SHORELINE PROTECTION
   countries having lost up to 80 per cent. Mangroves   Reefs and mangroves naturally form barriers and thus
   have been degraded by conversion to aquaculture,    inevitably provide some shore protection, a fact long
   timber extraction, use of wood for fuel and      recognized by coastal communities, fishers and vessels
   charcoal production, diseases and storms.       which use the sheltered waterways behind these
                               ecosystems. Both reefs and mangroves can themselves be
ECOSYSTEM BENEFITS                      damaged by strong winds and waves, and so their buffering
Coral reefs and mangroves provide benefits under the four  capacity is a balance between their resilience and their
categories of ecosystem services defined by the 2005     vulnerability. The current consensus is that:
                                 ❏ Reefs and mangroves play an important role in
Millenium Ecosystem Assessment:
  ❏ Regulating – e.g. protection of shores from storm       shore protection under normal sea conditions
   surges and waves; prevention of erosion.           and during hurricanes and tropical storms. At
  ❏ Provisioning – e.g. fisheries, building materials.      least 70-90 per cent of the energy of wind-
  ❏ Cultural – e.g. tourism, spiritual appreciation.       generated waves is absorbed, depending on how
  ❏ Supporting – e.g. cycling of nutrients, fish nursery     healthy these ecosystems are and their physical
   habitats.                           and ecological characteristics.
                                 ❏ In a tsunami, the buffering capacity of reefs and
They are among the most valuable ecosystems in terms of       mangroves is more variable and often reduced
their benefits to humankind:                    because of the different structure and form of
  ❏ Economic valuation of ecosystems needs to be         the waves and their much greater force. Distance
    treated with caution but annual values per km2        from the earthquake epicentre, the presence of
    have been calculated at US$100 000-600 000 for        inlets and headlands, the gradient of the
    reefs and US$200 000-900 000 for mangroves.         continental slope, shoreline elevation, the
  ❏ The small total area of coral reefs and mangroves       presence of dunes and other vegetation, and
    belies their importance in terms of fisheries,        density of habitation and infrastructure seem to
    other extractive uses, shoreline protection and, in     explain most of the variation.
    the case of reefs, tourism and recreation.
  ❏ Both ecosystems contribute significantly to      PROS AND CONS OF REHABILITATION AND RESTORATION
    national economies, particularly those of small    Both reefs and mangroves will recover naturally once a
    island developing states (SIDS), 90 per cent of    stress has been removed, but this can be slow; for example,
    which have coral reefs and over 75 per cent of    the reefs most seriously damaged by the tsunami may take
    which have mangroves.                 five to ten years to recover. New growth of coral colonies and

     In the front line

                                      ❏ The devastation recently wrought by hurricanes
     mangrove trees, and recruitment of coral larvae and
     mangrove seedlings, is balanced by erosion and breakdown      and tropical storms testifies to the priority that
     from both human-induced and natural stresses. The         must be accorded to the maintenance and
     chronic human impacts faced by these ecosystems are        enhancement of the resilience of natural coastal
     tending to slow recovery, and the highest priority is to      barriers such as reefs and mangroves.
                                      ❏ Post-tsunami and hurricane reconstruction
     reduce and eliminate these stresses. It is tempting to try to
     speed recovery of an ecosystem by active restoration, or      efforts provide an opportunity to introduce and
     repair. However, this is rarely totally successful because of   expand good coastal management practices.
     the difficulties involved in re-establishing full biodiversity   These may indeed help to mitigate damage from
     and ecological processes:                     future tsunamis but, since these are infrequent
       ❏ Mangrove restoration is relatively simple and        events, the more important consequence is
         large areas of new forest are being created using      mitigation of the impacts of the more certain, but
         volunteers and local labour. However, achieving a      gradual, changes due to global warming.
                                      ❏ Short-term, small-scale rehabilitation progr-
         mangrove forest with a full complement of
         biodiversity is a more complex and long-term        ammes should not take precedence over
         process, and it is questionable whether any         activities directed at the root causes of the
         programmes have yet achieved this.             decline in reef and mangrove health. Key tools
       ❏ Reefs, involving numerous species with very         include integrated coastal management, marine
         different life histories and poorly understood       protected areas, and monitoring and assessment
         growth and reproductive characteristics, are        for adaptive management.
                                      ❏ Governments, civil society and the private sector
         more difficult to restore. Many attempts have
         been made using a variety of techniques. Most        must recognize that, as with other benefits, there
         methods are costly and require considerable         is a price to pay for maintaining these eco-
         skill, and there are few examples of successful       systems. However, this is much lower than the
         sustainable reef restoration over large areas.       benefit received. For example, the estimated
                                       average operational management cost of a
                                       marine protected area is US$775 per km2, or less
     FUTURE                               than 0.2 per cent of the estimated global value of
     Investing in environmentally sustainable management        a square kilometre of reef or mangrove.
                                      ❏ Many of the world's wealthiest nations have
     and development of the coast will be more cost effective
     than restoring human livelihoods and ecosystems after a      jurisdiction over these ecosystems – more than
     catastrophe. The relatively small amount of damage         30 per cent of reefs are in countries classified as
     inflicted on coral reefs and mangroves by the           highly developed. They also have strong links
     2004 tsunami demonstrated the resilience of these         with less developed countries struggling with
     ecosystems to natural disturbance, but the worldwide        their management. Political will and concerted
     public concern generated also revealed our awareness of      action are needed – coral reefs and mangroves
     their vulnerability.                        are in the front line, and calling for attention.
                                                                  D Sato/UNEP/Topham
S Wells

                                                        In the front line

Global status of reefs and

                                   Mangroves and tropical coral reefs
Of the 177 countries in the world, rather less than half (44     countries is very unequal. Australia and Indonesia each
                                   have about 50 000 km2 of reef and account for nearly 35 per
per cent) have tropical coral reefs and about half have
mangroves. Our knowledge of the distribution of coral reefs      cent of the world’s reefs, and Indonesia alone has 23-25 per
and mangroves is now relatively good, as a result of regional     cent of the world’s mangroves. In general, other countries
                                   have less than 10 000 km2 of reef and less than 1 000 km2 of
and global mapping programmes using navigational charts,
satellite imagery and aerial photography, as well as more       mangroves (Spalding et al., 1997; 2001).
detailed field surveys.
     Both ecosystems occur principally in the tropics,      STATUS
with South-East Asia a major centre. Distribution between       The coastal biome, which makes up only 4 per cent of the

                                   Fig. 2: Distribution of tropical coral reefs and mangroves
Fig. 1: Area of coral reefs and mangroves

Coral reefs and mangroves are among the world’s rarest
ecosystems. Reefs cover an estimated 284 300 km2, or just 1.2 per
cent of the world’s continental shelf area (Spalding et al., 2001).
The total area of mangrove forest is less certain but is even
smaller, estimated at between 167 000 km2 (Valiela et al., 2001)
and 181 000 km2 (Spalding et al., 1997). As a comparison, tropical
and subtropical forests cover 23.3 million km2, an order of
magnitude larger (Millennium Ecosystem Assessment, 2005).

In the front line

planet’s total land area, is home to one-third of the world’s

                                                                    P Dustan
population, and this population is predicted to double over
the next 15 years. In many countries, such as island nations
and those with inhospitable and arid interiors, humankind
lives almost entirely on the coast. With the exception of
some isolated atolls, all reefs and mangroves lie adjacent to
the coast; more than half these ecosystems occur within 25
km of urban centres inhabited by 100 000 or more people
(Millennium Ecosystem Assessment, 2005). Not
surprisingly, the health and extent of both reefs and
mangroves have declined dramatically over the last century.
     Trends in reef health are well documented as

                                                                    P Dustan
assessments are carried out at regular intervals, through
numerous monitoring programmes, the results of which
are published in the biennial Status of the World’s Reefs
Reports (Wilkinson, 2004), the regional World Resources
Institute’s Reefs at Risk reports (Burke and Maidens, 2004;
Burke et al., 2002) and many national reports.
     Results from monitoring programmes indicate that
about 30 per cent of the world’s reefs are seriously
damaged, with possibly no pristine reefs at all remaining,
and it has been predicted that 60 per cent of reefs will be
lost by 2030 (Wilkinson, 2004). Using information on existing
and potential threats to reefs in 1998, the World Resources   Carysfort Reef, the largest and most luxuriant reef in the Florida
                                Keys, United States, in 1975 (higher) and 2004 (lower) showing the
Institute suggested that 27 per cent of all reefs are
                                catastrophic decline of living coral cover.
potentially at high risk and a further 31 per cent are at
medium risk of damage (Bryant et al., 1998). More recent
regional predictions, using the same method, paint an even
                                Reefs at risk in the Caribbean
more disturbing picture. A 2000 analysis estimated that
human activities potentially threaten 88 per cent of the    Nearly two-thirds of reefs in the Caribbean are potentially at risk
                                from human activities, according to a 2004 report, with over 40 per
reefs of South-East Asia, with 50 per cent at ‘high’ or ‘very
                                cent at ‘high’ or ‘very high’ risk, and about 28 per cent at low risk
high’ risk and only 12 per cent at low risk (Burke et al.,
                                (Burke and Maidens, 2004). In this region, elkhorn (Acropora
2002).                             palmata) and staghorn (A. cervicornis) corals have undergone
     As yet there are no equivalent global mangrove     massive die-offs (Gardner et al., 2003).

                                                             In the front line

                                       Fig. 3: Area of mangrove lost to human activities
      assessments, but several studies have shown this
                                       (per cent)
      ecosystem to be as much at risk as coral reefs. The
      amount of mangrove lost varies widely among countries
      but, where data are available, mangroves are on a
      declining trend. An estimated 35 per cent of mangrove
      forest has disappeared in the last two decades (Valiela et
      al., 2001), and some countries have lost 80 per cent of
      cover (Spalding et al., 1997). The average annual rate of
      disappearance (or conversion to other forms of land use)
      is estimated at 2.1 per cent, with the greatest rate of loss
      in the Americas (3.6 per cent). The annual rate of loss of
      mangroves thus exceeds the rate of disappearance of                           Source: Valiela et al., 2001
      tropical rainforests (0.8 per cent) (Valiela et al., 2001).
                                       little to the main structure of the reef (e.g. Agaricia) (Hughes
      Estimates for some locations suggest that rates of
      mangrove loss may be as high as 50 per cent a year        et al., 2003; Knowlton, 2001).
      (Alongi, 2002).                              Degradation of mangroves leads to long-term
          Over the last few decades there have been major     changes in the ecology of large areas of coastline. In
      changes in the appearance and quality of reefs and        particular, conversion of mangroves to shrimp farms, and
      mangroves, the result of a combination of many ‘drivers’ or   the subsequent aeration and use of fertilizers, alters the
      threats. These have both direct and indirect impacts that    composition and structure of the soil. Eventually ponds
      often trigger an escalating series of problems.         are abandoned, sometimes after only two to ten years, as
          Many reefs, for example, are undergoing a shift from   they are no longer suitable for production (Stevenson,
      a coral-dominated to an algal-dominated state. Corals have    1997). There is little chance of mangrove regeneration in
      been disappearing as a result of bleaching, disease, storm    the remaining barren lands. Leading causes of mangrove
      damage and a range of human activities, including        forest loss and degradation are conversion for
      overfishing, use of destructive fishing gear, anchor damage   aquaculture, use of mangroves for timber for
      and pollution. At the same time, algae have increased as     construction and other functions, and for fuelwood and
      herbivores and grazers, such as sea urchins and some fish    charcoal, conversion to rice paddies, and freshwater
      species, that keep them in control have declined through     diversion and coastal development for tourism and other
      disease and overfishing. Algae have further increased as a    purposes (Valiela et al., 2001).
      result of nutrient pollution. Where coral cover has started to
      increase there are indications that the so-called        THREATS
      framework-building corals (e.g. Acropora, Montastrea) that
      once dominated are being replaced by corals that contribute   Overexploitation and destructive fishing
                                       Many commercial fish species, such as rabbitfish
                                       (Siganidae), feed on algae, and their removal can result in
      The brown seaweed Chnoospora overgrowing branching corals.
                                       excessive algal overgrowth of corals. Removal of
Y Latypov

                                       ‘keystone’ species (those that play a particular role in an
                                       ecosystem) – such as triggerfish which prey on sea
                                       urchins – may be the cause of urchin population out-
                                       breaks which further degrade corals through bioerosion.
                                       Dynamite, small-mesh nets and nets that are dragged
                                       over the seabed, although illegal in many countries, are
                                       still used and cause widespread physical damage as well
                                       as removing or killing immature fish and other species of
                                       no commercial value.

                                       Habitat loss
                                       Mangroves can be completely wiped out when forests are
                                       cleared for salt production operations, for industrial,
                                       residential and tourism development, or, particularly, for
                                       aquaculture. In contrast, coral reefs generally suffer from

  In the front line

    In Honduras, shrimp farms have progressively transformed the coast of the Gulf of Fonseca since the early 1970s. Although there were still large
    areas of mangrove in 1987, by 1999 the only substantial forests were in protected areas such as Estero Real Nature Reserve (UNEP, 2005a).

    a gradual decline in quality rather than a sudden             Disease
    disappearance. However, mining for corals for use as            Coral diseases, rarely recorded until the 1970s, have had
    building materials can eliminate, or reduce to rubble,           a catastrophic effect on reefs, particularly in the
    large areas of reef. Although coral mining is illegal or          Caribbean, affecting 100 hard and soft coral species in 54
    regulated in most countries, it is still having a major          countries. The cause is still largely unknown, although
    impact in India, the Maldives, Sri Lanka and Tanzania
                                         Sediment plume in Monte Cristi National Park, Dominican Republic.
    (Wilkinson, 2004).
                                         Inland deforestation is causing sediment run-off on to nearby coral
                                         reefs. As a result, coral cover tends to be low compared with other
    Land-based sources of pollution                      less impacted areas.
    More than 77 per cent of the pollutants entering the oceans

    originate on land, and 44 per cent of these pollutants come
    from improperly treated wastes and run-off (Cicin-Sain et
    al., 2002). The nutrient content of the oceans has increased
    dramatically in recent years as a result of fertilizer and other
    agricultural run-off, sewage and aquaculture waste.
    Nutrients such as nitrogen and phosphorus deplete oxygen
    in the water and promote the growth of algae on reefs
    (Hughes et al., 2003).
        Many coastal development activities, such as
    residential, tourist, industrial and port development, involve
    land reclamation and dredging which invariably results in
    sediment being stirred into the water column.
    This reduces light penetration, may directly smother corals
    and can damage mangroves. Construction activities inland,
    agriculture and deforestation, and poor management also
    contribute to increased sediment.

                                                               In the front line
A W Bruckner

                                                                         Thomas Heeger
        Coral attacked by black-band disease.               Fishing with dynamite in the Philippines.

        both fungi and bacteria have been identified as pathogens         Furthermore, by 2100, rates of calcification (the
        in two cases (Porter, 2001; UNEP-WCMC, 2003). There are      process by which calcium is formed) on reefs may have
        indications that abrasion of massive corals through tourist    decreased by 17-35 per cent of pre-industrial levels as a
        activities may make corals more susceptible to disease       result of high levels of dissolved carbon dioxide in the
        (Hawkins et al., 1999).                      oceans (these are now 380 parts per million (ppm),
                                         compared with 280 ppm two centuries ago). This will cause
        Climate change                           weakening of coral skeletons and slower growth rates,
        There is now general consensus that extreme storm events      making reefs even less effective as breakwaters (Feeley et
        are becoming more frequent, and sea levels and           al., 2004; Kleypas et al., 1999).
        sea surface temperatures are rising as a result of global
        warming. Reefs are already suffering from bleaching events     Other threats
        that have increased significantly since 1975. In the        Individual tourists, tourist boats and anchors may have only
        Caribbean bleaching events are predicted to become an       a minor impact, but over time and in large numbers the
        annual event as current sea surface temperatures are in the    impact becomes significant (Hawkins et al., 1999; Zakai and
        upper temperature threshold for coral survival (Gardner et     Chadwick-Furman, 2002). Spills of oil and toxic chemicals,
        al., 2005; Hughes et al., 2003). Tropical storms are forecast   and dumping of other wastes, cause localized impacts to
        to become even more frequent and/or more intense          both reefs and mangroves. The introduction of alien species
        (Trenberth, 2005), and this will compound the problem,       is a threat to marine ecosystems that is growing rapidly with
        causing more damage to both reefs and mangroves and        increased shipping and susceptibility in systems degraded
        resulting in shorter recovery times between events (Hughes     by other stresses. Marine plants and animals can be
        et al., 2003).                           transported immense distances on the hulls of vessels or in
            The change on reefs from coral to algal dominance,    ballast water. Non-indigenous sessile species have been
        and from framework-building species to non-framework        introduced to reefs in Guam via ships’ hulls, and other alien
        species, may also compromise their ability to keep pace with    species are spreading on the reefs of Hawaii, outcompeting
        rising sea levels (Bellwood et al., 2004; Gardner et al., 2003).  native species (Eldredge, 2003).

In the front line

Value of ecosystem services
The Millennium Ecosystem Assessment (Millennium

                                                               C Ravilious
Ecosystem Assessment, 2005) defines four categories of
ecosystem services:
  ❏ provisioning – e.g. food, medicines,
   construction materials
  ❏ regulating – e.g. protection of shorelines,
   water quality maintenance
  ❏ cultural – e.g. tourism, spiritual beliefs
  ❏ supporting – e.g. maintenance of basic life
   support systems.
Coral reefs and mangroves provide benefits under all four

   Ecosystem services   Coral reefs                 Mangroves

   REGULATING       Protection of beaches and coastlines     Protection of beaches and coastlines from
               from storm surges and waves         storm surges, waves and floods
              Reduction of beach erosion          Reduction of beach and soil erosion
              Formation of beaches and islands       Stabilization of land by trapping sediments
                                     Water quality maintenance
                                     Climate regulation

   PROVISIONING      Subsistence and commercial fisheries     Subsistence and commercial fisheries
              Fish and invertebrates for the        Aquaculture
               ornamental aquarium trade          Honey
              Pharmaceutical products           Fuelwood
              Building materials              Building materials
              Jewellery and other decoration        Traditional medicines

   CULTURAL        Tourism and recreation            Tourism and recreation
              Spiritual and aesthetic appreciation     Spiritual – sacred sites

   SUPPORTING       Cycling of nutrients             Cycling of nutrients
              Nursery habitats               Nursery habitats

Techniques for valuing ecosystem services are still        There is, however, no single agreed total value for all
relatively new and untested, and the results of such        coral reefs or all mangroves, or even for the different
calculations must be interpreted with care. Putting        services provided by these ecosystems. Values vary
a monetary value on an ecosystem, however, can help to       according to:
                                   ❏ The location – e.g. reefs that are major tourist
demonstrate why its survival is important (IUCN/TNC/
World Bank, 2004; Turner et al., 2003). Economic values         destinations will have a higher value in terms of
can be calculated from the cost of the products (e.g. fish)       diving and other reef-related activities than
and services (e.g. tourism) derived from an ecosystem, or        those where tourism has not been developed.
                                   ❏ The length of time being considered and
from the cost of replacing a service (e.g. building
seawalls where natural storm protection has been lost).         whether a prediction for the future is involved

                                                   In the front line

   (e.g. all reefs are potentially of value for diving   Fig. 4: Economic value of the main ecosystem
                               services of coral reefs (billion US$)
   tourism but some may have no value at present).
  ❏ The ‘beneficiaries’ of the service, since some
   people will place a higher value on it than others.
  ❏ The method used and the assumptions made.

Furthermore, it is hard to calculate the economic value
of the aesthetic and ethical benefits of ecosystems, or of
the service some ecosystems provide through cycling
nutrients. Estimates of the ‘total’ economic value of an
ecosystem thus vary considerably and there is a risk
that using this approach underestimates the
ecosystem’s social benefits and overall importance. This
means that it is not always wise to use ecosystem                        Source: Cesar et al., 2003
valuations for policy making and investment decisions
(IUCN/TNC/World Bank, 2004). For example, the
                                  to US$3.5 million per km2 have been calculated
apparent higher value assigned to mangroves than coral
reefs (see Fig. 4) should not be interpreted to mean that     for mangroves (Sathirathai and Barbier, 2001).
they have a higher management priority. It is also true
that many of the activities that bring benefits, such as   Some of the variation can be explained by the location of
fishing and tourism, also damage reefs and mangroves,    the ecosystem. The value of reefs and mangroves for
and only careful management will allow the full values    shore protection (often measured per linear kilometre)
to be materialized.                     depends on the activities under way or planned along a
    However, if these limitations are taken into     particular stretch of coast. In Indonesia, reefs have been
account, an economic valuation can help to demonstrate    valued as follows (Cesar, 1996):
                                 ❏ Reefs adjacent to sparsely populated areas
the major role that reefs and mangroves play in the lives
of many people. Studies to date have shown that most        where agriculture is the main activity: US$829
benefit comes from provisioning services (i.e. fisheries      per km, based on the value of agricultural
and, for mangroves, timber and fuelwood), cultural         production that would be lost if there were no
services (tourism) and regulating services (shore         protection.
                                 ❏ Reefs adjacent to areas of high population
    The total annual economic value of reefs has        densities: US$50 000 per km, based on the cost
been estimated at between US$100 000 and US$600 000        of replacing housing and roads if coastal
per km2 (Cesar et al., 2003; Constanza et al., 1997) and      protection were lost.
                                 ❏ Reefs in areas where tourism is the main use:
the value of mangroves even higher, at more
than US$900 000 per km2 (Constanza et al., 1997).         US$1 million per km, based on the cost of
Figures are, however, very variable as some national        maintaining sandy beaches.
estimates show:
  ❏ Sri Lanka’s coral reefs have been valued at      Similar values have been obtained for the Caribbean,
    between US$140 000 and US$7.5 million per       varying from US$2 000 to US$1 million, with the highest
    km2 over a period of 20 years (Berg et al., 1998).  values in areas heavily developed for tourism (Burke and
  ❏ In American Samoa, mangroves, which cover less     Maidens, 2004).
    than 0.5 km2, have an estimated value            There are also several methods for valuing
    of US$104 000 per km2 (total value of about      mangroves. The storm protection value of mangroves in
    US$50 million a year) and reefs, which cover 222   Sri Lanka (before the tsunami) was put at US$7 700 per
    km2, are estimated at US$14 300 per km2 (total    km2 a year using a linear value (UNEP/GPA, 2003). A study
    value of US$318 million a year) (Spurgeon and     in Indonesia, in a different approach, calculated the
    Roxburgh, 2005).                   erosion control value of mangroves as being equivalent to
  ❏ In Thailand, very high values of US$2.7 million    US$600 per household per year (Ruitenbeek, 1992).

In the front line

Regulating services – shoreline

                                                              S H Grady
Although reefs and mangroves form natural barriers                 Hotel built behind mangroves, Kenya.
along the coast and thus inevitably provide some
protection to the shore, there is surprisingly little   Orissa, India, a powerful cyclone in 1999 and associated
scientific data to back this up. Most of the evidence is  waves caused extensive damage and human mortality,
observational and anecdotal, and relates to normal wave  but communities protected by mangrove belts were less
energy and storms. The calm lagoons inside reefs and    affected (Mangrove Action Project, 2005). In Viet Nam,
behind mangroves are immediately evident on tropical    mangroves have been observed to limit damage from
coastlines. Fishers use these sheltered waters as     cyclone waves and tsunamis and are said to have led to
navigation routes and for fishing, particularly during   large savings on the costs of maintaining sea dykes (Ha,
bad weather or the rough season monsoons. Holiday     2003; Tri et al., 1996).
makers and tourists benefit from the sheltered waters        In southern India, the distinct differences
for numerous recreational activities. The breakwater    between the Gulf of Mannar and Palk Bay, caused by the
role of reefs is emphasized by the importance accorded   protection provided by reefs, have led to these seas being
to the channels through them. These allow safe passage   equated with men and women by local villagers. The
to the lagoon and shore for fishing, navigation and    former is considered ‘male' because waves hit the reef
recreational activities, particularly in bad weather, a  and subside in force before they reach the shore. The
significance recognized by both coastal communities    latter is considered ‘female’ because waters are
and port authorities.                   generally calmer, but, if disturbed by storms, cause
    Coastal communities are often aware of the     greater damage due to the lack of a reef. Fishing
particular protection afforded by mangroves. In India   communities on Pamban, an area lying between the two
(Dahdouh-Guebas et al., 2005) and the Philippines     seas, still remember the 1964 cyclone that washed away
(Walters, 2004), villagers tell of how they have been   one village, while those behind reefs survived
protected from cyclones and typhoons in locations where  (Whittingham et al., 2003). Further north, in Chidambaran
mangroves are intact, but suffer where mangroves have   District the shore protection role of mangroves is
                              recognized by local people where a 113 km2 forest is used
been converted to shrimp farms or otherwise lost. In

                                                      In the front line

as a sacred grove and is traditionally known in Tamil as    reef flat between the reef edge and the shore, the more
Alaithi Kadukal, which means ‘the forest that controls the   wave energy is lost. In Egypt, for example, the reef flat and
waves’ (WWF, 2005).                       reef crest of the fringing reef off the tourist resort of
    Both reefs and mangroves also play a role in the    Hurghada dissipate wave energy considerably, protecting
accretion of coastlines. Reefs produce sand that forms     marinas and beaches (Frihy et al., 2004).
and replenishes sandy beaches and islands, the sediment
accumulating when corals and other calcified organisms

                                                                 S Wells
break down after their death. Mangroves help to stabilize
coastal land, by trapping sediment washed down in rivers
or from more general run-off. Remains of rows of
mangroves planted to stabilize the coast by early
generations of Maoris can still be seen in New Zealand
(Vannucci, 1997).
    The role of reefs as breakwaters is also
demonstrated by the many artificial structures that are
being installed for shoreline protection in locations with
no natural reefs. These often have a negative impact, in
terms of creating unwanted longshore drift, but they
nevertheless show how reef-type barriers influence wave
action, even being installed to improve surfing conditions
(Jackson et al., 2002).
    Although the general buffering capacity of reefs
and mangroves thus seems obvious, the mechanical
processes involved are complex, and the extent to which
they provide shore protection compared with man-made
barriers and other natural features is not yet fully
                                The lagoon behind the fringing reef here in northern Zanzibar
understood. Furthermore, the reef and mangrove         provides a shallow sheltered area where many activities can be
ecosystems are themselves damaged by events such as       undertaken.
storms and tsunamis. Hurricanes, for example, can
reduce coral cover significantly (Gardner et al., 2005).         The amount of energy reduction also depends on
Mangroves can be destroyed or seriously degraded by       the extent of fragmentation of the reef, as a continuous
hurricanes, through defoliation and uprooting by the      reef acts more as a breakwater than a reef that is broken
wind, erosion of the shoreline by waves and burial under    by channels. The state of the tide and the depth of water
sediment. In 1999 Hurricane Mitch destroyed 97 per cent     over the reef – at low tide a reef affords more protection –
of the mangroves of Guanaja, one of the Bay Islands in     and whether it 'plunges' on to or 'spills' over the reef top
Honduras (Cahoon and Hensel, 2002). Thus the buffering     also play a role (Gourlay, 1994; Kabdali and Turker, 2002).
capacity of both ecosystems is a balance between their     Quantifying what the reduction in wave energy may mean
resilience and their vulnerability, with many factors      in terms of shore protection is more difficult. In Sri Lanka,
involved. A healthy coral reef or mangrove, in the absence   however, it has been estimated that with current rates of
of human impact, acts as a self-repairing breakwater,      erosion and assuming that 1 kilometre of reef protects 5
                                kilometres of shoreline, 1 km2 of coral reef can prevent
with growth in equilibrium with the erosion caused by
                                2 000 m2 of erosion a year (Berg et al., 1998).
waves, storms and other processes.
                                     Mangroves dissipate the energy and size of waves as
WIND-GENERATED WAVES AND STORMS                 a result of the drag forces exerted by their multiple roots and
The waves normally seen on the ocean are generated by      stems. Wave energy may be reduced by 75
wind, and have most of their energy in the surface waters.   per cent in the wave's passage through 200 metres
The reef flat (the zone of a reef extending seaward across   of mangrove (Massel et al., 1999) but, as with coral
the lagoon) and the reef crest (the seaward edge of the reef  reefs, other factors also have an influence, including coastal
flat) absorb most of a wave’s force, often up to or more than  profile, water depth and bottom configuration. One study
90 per cent (Brander et al., 2004; Lugo-Fernandez et al.,    suggested that a 1.5-km belt of mangrove may be able to
1998; Roberts and Suhada, 1983). The greater the width of    reduce entirely a wave one metre high (Mazda et al., 1997).

     In the front line

                                         2004 tsunami, and the damage they received,
A Baird

                                         varied considerably.
                                             Despite initial fears, both ecosystems were less
                                         badly damaged than expected even on reefs in Aceh,
                                         Indonesia, which were within 300 km of the epicentre
                                         (Baird et al., 2005). In Thailand, of 175 reef sites surveyed
                                         on the Andaman coast after the tsunami,
                                         more than 60 per cent had little or no damage; 13 per
                                         cent were seriously damaged, however. Shallow reefs on
                                         wave-exposed islands and shorelines were most
                                         vulnerable, as were the northernmost coast and offshore
                                         islands (Phongsuwan and Brown, in press). At some sites,
                                         differences were even more localized: at Patong Bay,
                                         Phuket, reefs in the south were badly damaged but those
                                         in the north were almost untouched, a pattern that was
     Large boulder coral washed up on an Aceh beach following the
                                         reflected in the destruction on land (Edwards, 2005).
     tsunami of December 2004.
                                         Post-tsunami surveys in Thailand and Aceh show
     TSUNAMIS                                that most damage was in the form of overturning of
     Compared with a wind-generated wave, a tsunami has a          poorly attached boulder corals, breakage of branching
     much longer wave length and the wave energy is             corals, and smothering of the reef with sediment (Baird
     distributed throughout the entire water column and is         et al., 2005; Phongsuwan and Brown, in press).
     on a much greater scale. As a tsunami approaches the          Much greater damage was sustained by reefs directly
     shore and water depth decreases, the wave height            affected by the earthquake. Reef flats, with once diverse
     increases dramatically as energy is converted to            coral communities, have been permanently uplifted
     surface layers, this effect being more pronounced on          above the high water mark in many coastal areas of
     gradually shallowing shores (Kowalik, 2004; Mojfeld          Aceh and the Andaman and Nicobar islands (B. Brown,
     et al., 2000). Tsunamis can cause substantial damage          pers. comm.).
     at locations protected from wind-generated waves, as              An analysis by UNEP/GRID of more than 50 sites
     they tend to accelerate through channels and up inlets,        affected by the tsunami, using pre- and post-satellite
     rapidly increasing in height. They can also be reflected        imagery, indicated that there was greater coastal
     off obstacles and travel in different directions (Yeh et        flooding behind coral reefs (Chatenoux and Peduzzi,
     al., 1994). It is thus perhaps not surprising that           2005), perhaps because channels through the reef
     the roles of reefs and mangroves as buffers in the           accelerated the flow. The same result was found in Aceh

                                June, 2002                            January, 2005

     Many parts of the coast of Tamil Nadu in India were severely hit by the tsunami. Three villages behind the mangroves in Pitchavaram
     Sanctuary survived whereas the two in front were lost (Danielsen et al., 2005; Kathiresan and Narayanasamy, 2005). This could, however,
     have been due to the reduced force of the wave, as the continental slope drops to deep waters much more sharply here, compared with areas
     further south which suffered greater damage (Wood, 2005).

                                                                In the front line

      The once extensive mangroves around Banda Aceh in Sumatra, Indonesia, an area which suffered devastating damage and loss of life in the
      tsunami, had been largely replaced by shrimp farms, covering 360 km2 (UNEP, 2005b). Although loss of mangroves could have contributed to
      the destruction, the area was also very close to the epicentre of the tsunami, and thus vulnerable to substantial impact.

                                          dominated by genera such as Sonneratia or Rhizophora)
      (Baird et al., 2005), and studies on the Queensland coast
      of Australia have also shown that historically tsunamis        were damaged (Dahdouh-Guebas et al., 2005). It therefore
      have breached the Great Barrier Reef through passes in         seems that the 'quality' of the mangrove forest contributes
      the reef (Knott, 1997).                        in large measure to its buffering capacity, in addition to its
          Some studies have suggested that, in certain          size and the extent of regrowth if it had previously been
      locations, reefs did provide protection. In Sri Lanka, at       cleared. Tree density may certainly be important: one
      Hikkaduwa where the reefs are in a better condition than        study indicated that a 100 metre-wide belt of mangroves,
                                          with trees at a density of 30 per 100 m2, would be sufficient
      many in the country – and are protected in a marine park –
      the tsunami caused damage to a distance of only 50 metres       to reduce the flow pressure from a tsunami by as much as
      inland and waves were only 2-3 metres high. At Peraliya,        90 per cent (Hiraishi and Harada, 2003).
      just 3 km to the north but where the reefs have been              Analyses of satellite images of a large number of
      extensively affected by coral mining, waves were 10 metres       tsunami-impacted sites do not show clear correlations
      high, and damage and flooding occurred up to 1.5 km inland       between the presence of mangroves and reduced
      (Fernando et al., 2005, Liu et al., 2005). Detailed analysis of    shoreline damage (Chatenoux and Peduzzi, 2005; Wood,
      these areas is still needed, as other factors may also be       2005). In many cases the locations where mangroves have
      involved. Dunes were particularly important in providing        been reported to have helped protect the shoreline were
      protection in Sri Lanka (Liu et al., 2005).              out of the main path of the wave, or were adjacent to
          Initially, there were many observations suggesting       deeper water, and thus less susceptible to serious
      that mangroves both dissipated the force of the tsunami        damage. These findings demonstrate the importance, in
      and caught the debris washed up by it, and thus helped to       developing predictive models, of carefully analysing every
      reduce damage (IUCN, 2005). In several cases, mangroves        aspect of a site, both at the broad scale where satellite
      were also instrumental in saving lives by preventing          imagery can be useful and through detailed field surveys
      people caught in the backwash of the wave from being          and on-the-ground studies.
      pulled out to sea. However, as with coral reefs,                The general picture emerging since the tsunami
      subsequent studies showed that the benefit of mangrove         is that reefs and mangroves were not the main factor
      protection was rather variable. In India, bathymetry and        influencing the extent of damage on the coastline.
      coastal profile were most important in determining the         Nearshore bathymetry and coastline profile are probably
      impact, but less erosion was observed in the Andamans         the key factors determining the force of a wave at any
      behind mangroves than where there were no mangroves          particular coastal location. Shores adjacent to deep
      (Department of Ocean Development, 2005).                water tended to be less affected than those next to
          A survey of 24 lagoons and estuaries along the         shallow sloping shelves, regardless of the presence or
      south-west, south and south-east coasts of Sri Lanka          absence of reefs. The shape of the coastline is also
      which suffered the greatest damage showed that where          influential, with headlands often providing protection
      good quality mangrove communities occurred there was          while bays and inlets act as funnels, restricting and
      little destruction to the coast, and the mangroves           focusing the force of a wave. More research is required
      themselves were not badly harmed. However, forests           before it will be possible to predict where, and in what
      dominated by less typical mangrove species (i.e. those         way, a reef or mangrove will help to reduce the impact of
      that had been degraded in the past and were no longer         a tsunami.

In the front line

Other ecosystem services

Climate and global carbon cycle
Emissions of carbon dioxide from fossil-fuel combustion and
land-use changes are the leading cause of the build-up of
greenhouse gases. Forests, as well as crops, soil and other
organic matter, take up carbon (carbon sequestration) and
help to reduce the rate of global warming. Mangroves fix and
store significant amounts of carbon (Alongi, 2002) and they
play an important role in carbon sequestration, currently
absorbing an estimated 25.5 x 106 tonnes of carbon a year
(Ong, 1993).
    Although reefs play an important role in the carbon
budget, contributing 7-15 per cent of global calcium
carbonate production, they do not help with carbon
sequestration. Sedimentary carbonates, including corals,
coralline algae and the shells of other marine organisms,
are the largest reservoir of carbon on Earth, and so
fluctuations in the global calcium carbonate budget
influence atmospheric carbon dioxide concentration.
However, the chemistry of the system is such that although
the oceans themselves are a ‘sink’ (i.e. they take up carbon
dioxide), reefs are ‘sources’ or net producers of carbon     The number of dive operators along the Meso-American Barrier
                                 Reef has increased dramatically in recent years, reflecting the
dioxide, albeit on a small scale in terms of the global carbon
                                 growth of this leisure activity. In 2000, reef divers – numbering
budget, through the process of calcification (Suzuki and
                                 about 3.6 million – made up 10 per cent of all tourists to the
Kawahata, 2004).                         Caribbean. Divers, however, contributed 17 per cent of tourism
                                 revenue, spending about US$2 100 per trip, compared with
                                 US$1 200 for tourists in general. It has been estimated that in 2000
Water quality
                                 the net annual benefits from diver tourism in the Caribbean
Mangroves are capable of absorbing pollutants such as      amounted to US$2.1 billion, with US$625 million being spent
heavy metals and other toxic substances (Lacerda and       directly on diving on reefs (Burke and Maidens, 2004).
Abrao, 1984), as well as nutrients and suspended matter
(Ewel et al., 1998). This makes them natural wastewater     tourism constitutes a large, and possibly the fastest
filters, preventing many pollutants from reaching deeper     growing, sector. In Egypt, for example, the tourism sector as
water (Robertson and Phillips, 1995; Tann and Wong, 1999).    a whole accounts for more than 11 per cent of gross
                                 domestic product (GDP), and coral reefs have been central
CULTURAL SERVICES                        to the extremely rapid development of beach-based and
                                 diving tourism in south Sinai since the 1990s; this area now
Tourism                             accounts for some 25 per cent of tourism’s contribution to
Coral reefs add significantly to the value of coastal tourism,  national GDP (Jobbins, 2004).
supporting activities such as scuba diving, snorkelling and       The 2004 tsunami brought home the economic
glass-bottom boat operations. They also contribute to the    value of coastal and reef-based tourism, since this is vital to
formation of white sandy beaches. Tourism is the world’s     the economies of the Maldives, Sri Lanka and Thailand. In
largest industry, with 694 million international tourist     Sri Lanka, coastal tourism contributed about US$20 million
arrivals generating revenues of over US$500 billion in 2003.   a year to the national economy in the mid-1990s (Berg et al.,
The tourism industry is a major employer and source of      1998). A study in 2003 of the reefs of the Phi Phi Islands in
foreign exchange and is growing rapidly; it is expected to    Thailand, subsequently heavily damaged by the tsunami,
                                 valued them at US$624 300/km2 a year for tourism and
reach 1.6 billion arrivals by 2020. Beach-based leisure

                                                              In the front line

                                       valued species) in Belize, Honduras and Mexico is directly
S Wells

                                       dependent on the health of the adjacent barrier reef, the
                                       longest in the hemisphere. Sustainable annual catches of
                                       fish from reefs vary from 0.2 to 30 tonnes/km2, with an
                                       average of 5 tonnes/km2 (Jennings and Polunin,1995).
                                       Depending on the value of the fish, reef fisheries are thus
                                       potentially worth US$15 000-150 000/km2 a year, based on
                                       catch values of US$1-10 per kg (Talbot and Wilkinson, 2001).
                                       Reef fisheries in South-East Asia generate some US$2.4
                                       billion a year (Burke et al., 2002), and in the Caribbean
                                       US$310 million a year (Burke and Maidens, 2004).
                                           There is now a global market for reef species.
                                       Commercial reef fisheries are a major source of
                                       employment and foreign exchange, supplying export
                                       markets and retailers around the world, as well as the
                                       restaurant and hotel industries. The live reef fish trade
                                       supplies restaurants throughout South-East Asia with
     A mangrove boardwalk for tourists on Wasini Island in southern
                                       products from the Pacific and Indian Oceans (Hughes et al.,
     Kenya, managed by a local women's group, generates several
                                       2003). Tuna fisheries, such as those in the Maldives and
     thousand dollars a year which are used for maintaining the
                                       Lakshadweep, are often supported by reef-based bait
     boardwalk and for community development activities (IUCN, 2004).
                                       fisheries, and tuna themselves depend in part on reefs for
     recreation, with a total value of US$205 million a year      their food (Whittingham et al., 2003). Reef-based
     (Seenprachawong, 2003). This provides a major incentive      recreational fisheries generate over US$100 million
     for careful management of the reefs post-tsunami, to        annually (Cesar et al., 2003).
     ensure that they recover rapidly and continue to provide          A large proportion of fish and invertebrates in the
     tourism benefit.                          aquarium trade comes from coral reefs, shipped to the 1.5-
         Mangroves are not traditionally thought of as tourist   2 million people in Europe and North America who have
     attractions or suitable sites for recreation, but this is     aquaria. Sri Lanka, for example, earns about US$5.6 million
     changing fast with the realization that this ecosystem       a year exporting reef fish to about 52 countries, an activity
     provides a fascinating educational experience and also       that supports directly and indirectly around 50 000 people.
     harbours a range of unusual species that can be easily       Large quantities of corals, shells, starfish, pufferfish and
     observed once boardwalks have been installed. Visits to      other species are used in the curio trade. Reef-based
     mangroves and birdwatching tours are now generating
     significant revenue for local communities.
                                                                          S Wells


     Fisheries and other marine products
     Coral reefs and mangroves support numerous different
     types of fishery: artisanal, commercial and recreational;
     food, curios and souvenirs, bait, and items for decoration;
     and fish, lobsters, crabs, molluscs, sea cucumbers and
     many other species. However, much of the harvesting of
     these species, as well as of species taken for non-food
     purposes, is unsustainable, and current economic benefits
     may thus be short term.
         Of the estimated 30 million small-scale fishers in
     the developing world, most are dependent to some extent
     on coral reefs for food and livelihood. In the Philippines,
     more than 1 million small-scale fishers depend directly on
                                       Some estimates suggest that reefs contribute up to 25 per cent of
     coral reefs for their livelihood. The productivity of the     the annual total fish catch in developing countries, providing food
     fisheries sector (shrimp, lobster, conch and other high-      for 1 billion people (Cesar et al., 2003).

   In the front line

                                       also used in large quantities locally for house, boat and
P Scott

                                       jetty construction. Mangrove timber is particularly
                                       valuable for construction as it is resistant to rot and to the
                                       boring activities of many marine invertebrates. Wood
                                       from several mangrove species has a high calorific value
                                       and is thus of value both directly as fuelwood and as
                                       charcoal. Mangrove wood was used as fuel in many of the
                                       early train engines in India, and it is still widely used in
                                       kilns to make lime (often using live corals from adjacent
                                       reefs). The Matang mangroves in Malaysia provide
                                       forestry products (timber and charcoal) with a value of
                                       US$30 000/km2/year, and totalling US$10 million a year
                                       (Talbot and Wilkinson, 2001).
                                           Mangroves provide a variety of traditional products.
                                       Tannins from mangroves were used to coat and preserve
                                       wood, nets and other fishing gear, as well as being used as
                                       a dye for cloth. In several countries, mangrove leaves
                                       provide fodder for cattle and goats. Mangrove forests have
                                       long been an important source of honey and beeswax.
     The high-value, low-volume nature of the aquarium trade means
     that it could provide a livelihood for many people if carefully   Avicennia germinans in Florida in the United States is
     managed: a kilo of aquarium fish was worth nearly US$500 in 2002,
                                       particularly valued, as the bees that use this species make
     compared with a kilo of food fish which sold for about US$6
                                       high-quality honey, and large quantities were produced
     (Wabnitz et al., 2003).
                                       until the late 1800s when progressive loss of the best
     curios provide significant export revenue, but the souvenir     forests led to a decline in production. Honey has been
     trade is largely unregulated and the benefits from it may be    gathered from mangroves on a subsistence basis in
     short term.                             numerous countries, and, with a renewed interest in this
          Mangroves are important as breeding and nursery      product, the activity is being developed on a small-scale
     areas for fish and prawns that form the basis of major       commercial basis in many places (Horst, 1998).
     fisheries (Bann, 1997; Sasekumar et al., 1992). Annual
     commercial fish harvests from mangroves have been          Pharmaceuticals
     valued at from US$6 200 per km2 in the United States to       Marine organisms often contain pharmaceutically active
     US$60 000 per km2 in Indonesia (Bann, 1997). An estimated      compounds, many of the source species coming from reefs.
     75 per cent of the commercially caught prawns and fish in      Reef organisms have provided an HIV treatment and a
     Queensland, Australia, depend on mangroves for part of       painkiller, while a large part of current cancer drug
     their lives and on nutrients exported from the mangroves to     research focuses on coral reef species (Millennium
     other ecosystems (Horst, 1998). The annual market value of     Ecosystem Assessment, 2005). A study in Indonesia
     seafood from mangroves has been put at US$7 500-          estimated that mangroves provide a potential net benefit of
     167 500/km2 (Millennium Ecosystem Assessment, 2005).        US$1 500 per km2 (US$15/hectare) for medicinal plants
     With fish catches averaging 1.3-8.8 kg an hour, a 400-km2      (Ruitenbeek, 1992).
     managed mangrove forest in Matang, west Malaysia,
     supports a fishery worth US$100 million a year           SUPPORTING SERVICES
     (US$250 000/km2/year). Many commercial shrimp fisheries       The waters around mangroves are generally rich in
     are dependent on mangrove-fringed coastlines and          nutrients, as a result of the organic matter produced by the
     estuaries including those in Central America and East        trees and plants themselves, and also from the sediment
     Africa. In the Gulf of Panama, the fisheries for shrimps and    that is trapped around the roots. Mangroves produce about
                                       1 kg litter/m2 annually, which forms the basis of a complex
     fish generate an estimated US$95 000 per kilometre of
     coastline (Talbot and Wilkinson, 2001).               food chain and some of which is exported with the tide. As
                                       a result mangroves support an abundant and productive
     Mangrove forest products                      marine life, and often act as spawning areas, as well as
     Several mangrove species provide high-quality            nursery areas, sheltering juveniles of species that spend
     commercial timber, used for building and for making         their adult lives in other ecosystems such as coral reefs and
     newsprint, matchsticks and matchboxes. Mangroves are        seagrass beds (Mumby et al., 2004).

                                                      In the front line

What happens when ecosystem
services are lost?

Just as it is hard to calculate accurately the economic value   coral reef degradation continuing through to 2050 could
of different ecosystems, it is equally difficult to predict the  reduce benefits from fisheries, dive tourism and shore
cost to society of losing their various services. It was thought  protection by a predicted total of US$350 million to US$870
that the bleaching event of 1998 in the Indian Ocean would     million over that period (Burke and Maidens, 2004).
have a major impact on tourism and fisheries. It was
estimated, for example, that Tanzania would potentially      LOSS OF REGULATING SERVICES
suffer a direct loss of US$20 million from tourism revenue     The impact of the loss of the protective functions of
(Westmacott et al., 2000a). However, neither sector        coral reefs and mangroves is already being felt in
underwent the expected decline: tourism fluctuated but       some countries. Parts of Sri Lanka, India, Indonesia
probably more as a result of worldwide political and        and the Maldives, where coral mining and collection
economic changes; while fisheries are still in decline largely   has almost eliminated some reefs, have already
because of overexploitation.                    seen serious erosion.
     Both the 1997 bleaching and the 2004 tsunami were         In Sri Lanka, erosion on the south and west coasts
single, if acute, events, and reefs and mangroves are       now averages an estimated 40 cm a year, considered to be
expected to recover from damage incurred. A more typical      partly due to damage to reefs. Some US$30 million has
scenario is of reefs and mangroves undergoing steady        already been spent on breakwaters and other constructions
decline. Ecosystems that can no longer provide their full     to curtail this, and it has been estimated that the cost of
ecological services have a social and economic ‘cost’ to      replacing the coastal protection provided by these reefs
humanity, which can be felt in areas or situations many      would be US$246 000-836 000 per km (Berg et al., 1998). A
miles away. Ultimately, therefore, degradation of coral reefs   hotel in West Lombok, Indonesia, spent an average of
and mangroves will cause loss of fishing and tourism        US$125 000 a year over a seven-year period restoring its
revenue and other forms of livelihood, loss of export       250-metre-long beach, which had been eroded largely
earnings, malnutrition due to lack of protein, increased      because of offshore coral mining (Riopelle, 1995).
coastal erosion, and destruction from storms and              Modelling and predictions of the impact of the loss
catastrophic natural events.                    of natural shore protection provide dire warnings. Modelling
     It is predicted that, for example, over a 20-year     of the changes in wave energy striking some island
period, blast fishing, overfishing and sedimentation in      shorelines in the Seychelles (Sheppard et al., 2005)
Indonesia and the Philippines could lead to a net economic     indicates that wave energy has recently doubled as a result
loss of US$2.6 billion and US$2.5 billion respectively for     of sea level rise, loss of corals from reef flats due to
these two countries (Burke et al., 2002). In the Caribbean,    bleaching, and changes in reef crest profiles and wave

        In the front line

                                             communities in the tropics, through loss of earnings and
S Westmacott

                                             food security. Both overexploitation and habitat deterioration
                                             (particularly of nursery areas which causes disruptions to
                                             marine productivity) are leading to reduced catches in most
                                             tropical regions. For the Caribbean, it is predicted that, in the
                                             absence of reef degradation, fisheries production in 2015
                                             could be 100 000 tonnes, with a revenue of US$310 million.
                                             However, with the reef degradation that is projected to
                                             occur, production may be 30-45 per cent less (60 000-70 000
                                             tonnes), and revenue only US$140 million (Burke and
                                             Maidens, 2004).

                                             LOSS OF CULTURAL SERVICES
                                             Scuba divers specifically look for coral reefs with rich live
                                             coral, high fish and invertebrate diversity and clear water. In
                                             the long term, degradation of reefs will reduce their value to
                                             the tourist industry. Reefs will provide less interesting diving
                                             and snorkelling, poorer sport fishing and, where erosion has
        In the Maldives, a reef flat adjacent to the capital of Male was filled
        using coral rubble and causing sedimentation of nearby reefs.       taken hold, less attractive beaches. For the Caribbean, it is
        Their degradation was partly responsible for reduced shore
                                             predicted that, if reefs undergo no further deterioration, net
        protection and extensive flooding in 1987, which resulted in 20-30
                                             benefits from scuba diving could grow to US$5.7 billion by
        per cent of the new infill being lost. Subsequently, artificial
                                             2015. If reef health deteriorates further, however, dive
        breakwaters of concrete tetrapods were installed at a cost of
        US$10 000 per metre (or US$10 million per kilometre) (Brown,       revenue could amount to only US$5.4-5.6 billion,
        1997). Not only was this expensive, but it did not prevent serious
                                             representing a future ‘loss’ of 2-5 per cent (Burke and
        flooding during the tsunami.
                                             Maidens, 2004). Already it is widely believed in Florida,
        regime. The models predict that, over the next decade, it         United States (although data are lacking) that the decline in
        will double again as a result of further damage to coral         reef quality is partly responsible for the shift from high-
        reefs. The consequences of this will depend on the shore’s        value, low-volume tourism to budget travellers; this reduces
        composition, but there will almost certainly be increased         revenue and potentially, if large numbers are involved,
        erosion on sandy shores.                         further contributes to the degradation of the reefs (T.
            In the Caribbean, more than 15 000 km of shoreline        Agardy, pers. comm.).
        could experience a 10-20 per cent reduction in protection
        from waves and storms by 2050 as a result of coral reef

                                                                               R A Patzner/University of Salzburg
        degradation (Burke and Maidens, 2004). The economic
        costs to Australia from a degraded Great Barrier Reef as a
        result of the predicted impact of global warming have been
        put at US$2.5 billion to US$6 billion over 19 years (Hoegh-
        Guldberg and Hoegh-Guldberg, 2004).
            Loss of mangroves causes saltwater intrusion and
        deterioration of groundwater quality, as well as the
        disappearance of the filtering mechanism provided by the
        roots and the ecological characteristics of this ecosystem.
            Mangroves play a sufficiently important role in the
        global carbon cycle that it has been estimated that the loss
        of 35 per cent of the world’s mangroves (Valiela, 2001) over
        the last two decades has resulted in the release of large
        quantities of stored carbon, thus further contributing to the       The commercially important rainbow parrotfish Scarus guacamaia
        greenhouse effect (Cebrian, 2002).                    in the Caribbean depends on mangroves as a juvenile but lives on
                                             reefs as an adult. It is far less common on reefs with no adjacent
                                             mangroves, and is one of probably many species that are declining
                                             from loss of habitat as well as overfishing (Mumby, et al., 2004).
        The degradation of reefs and mangroves is already having a        Local extinctions have been reported where mangroves have been
        major impact on the livelihoods of thousands of coastal          cleared, as at Glover’s Atoll in Belize (A. Edwards, pers. comm.).

                                                           In the front line

       Natural recovery – or rehabilitation
       and restoration

       Although our instinct is to repair or restore something                       Mangrove restoration.
       that has been damaged, there is often an argument for
       allowing natural recovery. There are, indeed, many      There are two terms in common use: ‘restoration’, which
       examples of reefs and mangroves recovering from a       means that all the key ecological processes and functions
       major impact such as a hurricane without human        and all the former biodiversity are re-established; and
       intervention. Although recovery may seem slow, natural    ‘rehabilitation’ which means that most, but not all, are re-
       regeneration increases the likelihood that the ecosystem   established. Most experience so far with reefs and
       will return to what it was before.              mangroves is in terms of rehabilitation.
           The many chronic, long-term impacts now            Mangrove rehabilitation can be relatively simple
       affecting these ecosystems often slow the rate of       since comparatively few species are involved. However,
       recovery. On reefs, for example, the shift from a coral-   rehabilitation of reefs is more complex because coral
       dominated to an algal-dominated ecosystem means that     reproductive biology and growth rates are still poorly
       new coral recruits are quickly outnumbered and those     understood, many species are involved and the
       that settle often have little chance of survival. The focus  techniques are complex and expensive, requiring scuba-
       now needs to be on removing the causes of this        diving and other special equipment and materials. Reef
       imbalance, and eliminating stresses in order to        rehabilitation projects have so far been largely
       encourage natural recovery of damaged ecosystems       experimental and have involved only small areas (less
                                      than 100 m2). A careful evaluation of the methods
       (Edwards and Clark, 1998; Cahoon and Hensel, 2002).
           However, there may be certain situations or      available must be undertaken to determine feasibility and
       conditions when active intervention is necessary or      cost effectiveness before any attempt at rehabilitation is
       beneficial, for example where an ecosystem has        made. Research into coral reef restoration is currently
       particularly high economic value or scientific interest.   under way through the GEF/World Bank Coral Reef

In the front line

Targeted Research and Capacity Building for          two years. Natural recovery of mined reefs in the
Management project (Edwards, 2004).              Maldives has been particularly slow (Clark and
    Reefs and mangroves comprise different comb-      Edwards, 1994). Reefs in marine parks in eastern
inations of species and occur in a variety of physical     Indonesia, which had previously suffered from long-
conditions and locations. These factors, combined with the   term dynamite fishing, show little sign of recovery after
type and scale of damage suffered, will affect recovery    seven years, despite good water quality and larval
processes and thus any decisions about rehabilitation.     recruitment. The vast quantities of broken rubble act as
                                ‘killing fields’ for juvenile corals, abrading or burying
CORAL REEFS                          the newly settled recruits (Fox et al., 2003). Reefs that
Reefs will generally recover provided there is an adequate   suffered light damage from the 2004 tsunami in
supply of larvae of corals, fish and invertebrates, and as   Thailand are predicted to take only three to five years to
long as chronic disturbances such as sediment, pollution    recover; those that received greater damage may take
and overfishing are minimized. Recovery involves two      five to ten years. However, the rates of recovery will
processes: the settlement of larvae which then develop     depend on whether the reefs suffer other impacts in the
into new coral colonies; and growth of the remaining coral   coming years, particularly bleaching which has
colonies and fragments. Both processes are affected by     occurred several times in Thailand in the past
the prevailing environmental conditions and by the extent   (Phongsuwan and Brown, in press).
of the damage. New coral growth and recolonization of         The main approaches to rehabilitation of coral
fish populations will start to occur within one to two years  reefs are (Westmacott et al., 2000b):
                                  ❏ Increasing the area of substrate for settlement
of a damaging event or the end of damaging activities.
    Coral larvae require hard surfaces, preferably        of coral larvae by installing artificial surfaces,
coral rock or coralline algae, for settlement, and so         e.g. concrete blocks, wrecks or other purpose-
seaweeds, sediment and debris on the seabed will reduce        designed structures. Stabilizing or removing
coral recruitment. However, coral spawning can take
place quite normally after a natural event such as a

hurricane. For example, in Guam, after a typhoon, coral
spawning took place at the normal time and even broken
coral fragments were seen to spawn.
     Coral growth rates are highly variable,
depending on the species, the location of the colony on
the reef, the geographical location of the reef and
environmental conditions. Branching corals grow
relatively fast (10-20 cm a year) but are easily broken by
waves and storms. Massive corals grow very slowly (5-
25 mm a year) but may survive for hundreds of years;
colonies more than 1 000 years old have been found.
The reef as a whole grows more slowly than its
individual corals, as it is constantly being eroded, and
upward growth on reef flats is only about 4 mm a year,
while deeper reef thickets grow at about 10 mm a year.
The breakdown of coral skeletons results from either
mechanical damage or from ‘bio-eroders’, which
include sea urchins that graze on fine algae on the
surface of corals and abrade them in the process, and
sponges that bore into corals and weaken their
                                A major industry has developed in recent years to build artificial
                                reefs, such as this ‘Reefballs’ breakwater, to replace the original
    The speed of a reef’s recovery from major       natural reefs and create new amenity value. Although the costs of
damage thus depends on the balance between the         such structures are decreasing, this approach is expensive, and
                                not feasible for large areas; most importantly, an artificial
growth of coral colonies and their erosion. Recovery
                                structure such as this will never replace all the ecosystem
time is generally a matter of decades (10-50 years) and
                                services of a natural reef. Before investing in potentially risky
is longer on reefs subject to other long-term stresses,    'engineering' solutions to reef restoration, it is essential to seek
although the process of recovery can start in as little as   advice from scientists and other experts.

                                                             In the front line

J Harris

                                        Mangrove regeneration is affected by the patterns of
                                        damage (e.g. broken branches, impact from debris,
                                        sediment disturbance) and by the characteristics of the
                                        area. After storms and impacts such as a tsunami,
                                        sediment scouring leaves inorganic substrates that are
                                        difficult for mangroves to colonize. Sediment turnover may
                                        also expose and/or dump onto existing mangroves material
                                        in which there has been long-term accumulation of heavy
                                        metals, hydrocarbons and other contaminants that inhibit
                                        seedling establishment and survival (Ellison and
                                        Farnsworth, 1996; Cahoon and Hensel, 2002). As with reefs,
                                        for effective recovery it is essential that the causes of the
                                        damage are eliminated. Even when disturbance is reduced,
                                        the altered soil conditions (e.g. increased acidity where
                                        aquaculture was previously carried out) and limited natural
                                        dispersal of many mangrove species mean that natural
                                        recovery can be very slow.
                                             Most mangrove species produce propagules that
                                        are relatively easy to collect and plant and, in the right
                                        conditions, growth is fast. Restoration projects usually
      Reef restoration projects are under way in many areas, as here in
      the Solomon Islands. The tsunami gave fresh impetus to such     involve the direct planting of propagules (particularly for
      projects but they will need careful assessment. Experience to date
                                        Rhizophora spp.) in the recovery area, although
      suggests they are appropriate only at the scale of tens to at most
                                        seedlings and saplings can be grown up in advance in
      hundreds of square metres, for example on reefs damaged by
                                        nurseries. The exact technique to be used will depend on
      shipping or used by tourists.
                                        the species involved, whether the soil needs treatment
         loose or soft substrate, such as coral fragments        (for example to reduce acidity) or physical reworking (to
         and seaweeds, can also help, but this procedure        create a suitable grain size), the season, the
         requires care and expert help. New surfaces          developmental stage of the propagules and the
         can be created by passing an electric current         resources available. Replanting is generally most
         through metal to cause deposition of calcium          successful in relatively sheltered areas, but is also
         carbonate    (electrolysis). This   requires      carried out in more exposed areas where the main aim is
         considerable financial and human investment,          control of soil erosion (Stevenson, 1997).
         and the long-term impact of the current in the             Partly because of the ease with which propagules
         water is not known.                      can be replanted, many mangrove restoration schemes
        ❏ Transplanting coral fragments or colonies from         have been undertaken, often as a forestry production
         healthy reefs to damaged reefs or to artificial        initiative. Replanting schemes in Matang, Malaysia (Chan,
         substrates. Many species survive transplantation        1996), Thailand (Fast and Menasveta, 2003) and East Africa
         provided environmental factors are favourable,         (Kairo et al., 2001) have been successful, although
         but the process requires significant labour, and        rehabilitated mangroves often lack their full biodiversity
         transplanted fragments are easily dislodged by         and ecological processes (Ellison, 2000). Many of the Asian
         waves and human disturbance, or can easily be         countries affected by the 2004 tsunami have embarked on
         buried or smothered. In addition, there is a risk of      ambitious replanting programmes which are nevertheless
         damaging healthy reefs by removing corals from         a first step. Indonesia, for example, has initiated a four-
         them. Coral fragments can also be transplanted         year operation to plant 150 000 hectares of mangroves
         to a protected site and ‘grown out’ (or ‘farmed’) to      along the coast of Aceh where 300 000 hectares of
         a certain size before being used for rehabilitation      mangroves were destroyed. Such programmes will require
         (Epstein et al., 2003).                    careful monitoring and assessment if full restoration is to
        ❏ ‘Repairing’ the reef: Under some circumstances,        be achieved. There is some evidence that greater success
         it is possible to cement pieces of reef, or even        in recovering the biodiversity is achieved when the
         coral colonies, together, using glue, special         replanting is carried out in association with integrated
         cements, plastic or other binding agents.           aquaculture systems (Ellison, 2000).

            In the front line

            Mangroves and coral reefs on
            tropical coastlines of the future
            Devastating as they were, the tsunami of December 2004    matter of urgency, and alternative livelihoods found for
            and recent tropical storms have sent a clear message that   those dependent on the activities that cause damage.
            investing in environmentally sound development and      Good coastal planning can considerably reduce
            sustainable management of the coastal environment will,    vulnerability to natural disasters, as well as help
            in the long run, be more cost effective than restoring    safeguard other regulatory services such as water quality
            human lives and ecosystems after a catastrophe. Tsunamis   maintenance. Full implementation of the UNEP Global
            are relatively rare events compared with hurricanes and    Programme of Action on Land-based Sources of Pollution
            cyclones – fewer than 100 tsunamis were recorded over the   will go a long way towards helping to maintain the
            last 300 years in the Indian Ocean (Dahdouh-Guebas et al.,  regulating services of reefs and mangroves.
            2005; Department of Ocean Development, 2005) compared
            with three tropical cyclones a year (Dahdouh-Guebas et al,  MAINTAINING PROVISIONING SERVICES
            2005). Evidence for the shore protection benefits of coral  The sustainable exploitation of reef and mangrove
            reefs and mangroves is currently less for tsunamis than it  fisheries and other resources is a recognized global
            is for storms. This, however, does not lessen the urgency –  priority. There are some success stories, such as the
            the devastation recently wrought by hurricanes and      harvesting of mangrove timber over a 20-30 year rotation
            typhoons testifies to the priority that must be accorded to  period in Bangladesh, Malaysia and Thailand. Much
            shore protection measures, of which maintenance of      greater attention must, however, be paid to fisheries
            natural coastal barriers such as reefs and mangroves     management. Techniques and approaches are well
            must be among the first.                   developed but often poorly implemented. The FAO Code of
                There are no simple management models for      Conduct for Responsible Fisheries enshrines many of
            mangroves or reefs. The variability of these ecosystems    these, including elimination of destructive fishing gear,
            means that a good understanding of local characteristics   establishing no-take areas, and emphasizing the need for
            is essential. In the case of mangroves, even though a     management plans, developed with the full involvement
            common feature is their regular inundation by the sea, the  of fishers and users, that are fully enforced. In Sri Lanka,
            extent of this inundation and the tidal regime vary greatly  where 80-95 per cent of the fishing fleet was destroyed in
            as do their species composition and the chemical and     areas affected by ∆2the 2004 tsunami, there was an
            microbial characteristics of the soils, all of which affect  opportunity to introduce measures, such as reduction of
            their resilience and ability to recover.           overcapacity, to ensure sustainability. However, in the
                                           rush to provide humanitarian aid, fishing gear and boats
            MAINTAINING REGULATING SERVICES                have been distributed in large numbers and without
            Human activities that weaken reefs and make them less     consideration of the long-term future. This demonstrates
            effective breakwaters must be regulated or halted as a    the need for a much greater understanding by the public
                                           and decision makers of the management requirements of
Cancún Travel Online

                                           nearshore tropical fisheries.

                                           Thirty years ago, Cancún in Mexico, lying at the top of the great
                                           Meso-American Reef System, was a small fishing village. Since
                                           then, it has grown to a resort that receives more than 3.5 million
                                           visitors annually, on top of its 650 000 residents, and has suffered
                                           considerable environmental problems, particularly in the form of
                                           numerous hurricanes, such as Ivan in 2004 (left) and Emily and
                                           Wilma in 2005. In 2001, Guidelines for Low-Impact Tourism were
                                           produced for the state of Quintana Roo (Molina et al., 2001). These
                                           aim to ensure that further tourism development, particularly in the
                                           Costa Maya to the south of Cancún, will avoid many of the existing
                                           problems, and will contribute to the sustainable development of
                                           this region without increasing its vulnerability.

                                                               In the front line

    The Sundarbans, lying at the southern end of the Ganges River and straddling the border between India and Bangladesh, is the largest
    continuous area of mangrove in the world. The area provides a livelihood for more than 300 000 people, protects them from cyclones and tidal
    waves and is an important source of revenue for both countries through commercial timber which is harvested on a 20-year felling cycle. The
    total extent – some 6 050 km2 (Spalding et al., 1997) – has not changed significantly in the last 25 years, although there are concerns that
    forest quality may be declining. The relative success of the Sundarbans is largely due to its management which has been aimed at taking
    advantage of the mangroves’ provisioning and regulatory ecosystem services. It has been managed as a commercially exploited reserved
    forest since 1875; wildlife sanctuaries and national parks protect key biodiversity areas, and the area is both a World Heritage and a Ramsar
    site. Since the 1970s, the Sundarbans has also been managed as a protective belt against storm damage.

    MAINTAINING CULTURAL SERVICES                      recognition of the role of communities in the stewardship of
    The vulnerability of the tourism industry to natural events       natural resources, and the numerous examples of how this
    was made very clear by recent hurricanes as well as the         can be successful, will help to ensure that the cultural
    2004 tsunami. Maintaining the ecosystems on which the          services of reefs and mangroves continue to be valued.
    industry depends is thus of paramount importance to
    both governments and the private sector. The               ESSENTIAL MANAGEMENT TOOLS
    International Ecotourism Society (Halfpenny, 2002), the         There is no shortage of guidelines, codes of practice and
    Convention on Biological Diversity (CBD, 2004), the           information on how to manage reefs and mangroves but
    Center for Environmental Leadership in Business             there is there is still a notable lack of commitment to
    (CELB/CORAL/ IHEI/TOI, 2004) and others have produced          using and implementing them. The UNEP Regional Seas
    guidelines to promote sustainable tourism. Political will        Programme is among the organizations trying to reverse
    and individual commitment are now needed to ensure            this, by helping countries to work together to protect
    their implementation.                          these ecosystems, recognizing that success involves
        Although many coastal communities have              transboundary action, regional co-operation and clear
    traditionally valued the ecosystems on which they depend,        demonstration of successful approaches (see for example
    much of this understanding has been eroded. The growing         UNEP 2004). Key management approaches that must be

In the front line

promoted include integrated coastal management (ICM),       construction set-backs, green belts and other
marine protected areas (MPAs), and improved resilience       no-build areas.
and adaptive management.                   Priority technical measures
                                 2 Promote early resettlement with provision for
Integrated coastal management                   all basic livelihood needs.
Coastal development is often ad hoc and based on         3 Enhance the ability of natural ecosystems to
numerous unconnected small decisions, or, where plans       provide protection by conserving, managing and
exist, may be illegal as a result of poor enforcement of      restoring wetlands, mangroves, seagrass beds,
regulations (Kay and Alder, 2005). National and local ICM     and coral reefs, and by seeking alternative
programmes can go a long way to improving coastal         sustainable sources of building materials.
management. The links between impacts on the coast and      4 Promote design that is cost-effective and
watershed management need to be recognized. Plans         consistent with best practices, favouring soft
should take into account soils, topography and the need to     engineering solutions to coastal erosion control.
protect vulnerable ecosystems. Areas needing           5 Respect traditional access and uses of the
rehabilitation must be identified, as well as areas where     shoreline.
construction should be restricted or banned.           6 Adopt ecosystem-based management measures;
    In particular, the construction industry must       promote sustainable fisheries management;
respect environmental principles (such as set-back         encourage low-impact aquaculture.
regulations), and ensure that pollution and sedimentation    7 Promote sustainable tourism.
are minimized through measures such as the use of silt    How to apply the principles
curtains, and building in the dry rather than the wet      8 Secure commitments from governments and
season. Incorporating knowledge of coastal processes        international organizations to abide by the
and applying best management practices for beaches,        principles.
lagoons, coastal vegetation, energy, sewage treatment,      9 Ensure public participation.
solid waste and wastewater into planning and          10 Make full use of tools such as strategic
infrastructure are essential. Construction behind reefs       environmental assessment, spatial planning and
will need particular care, not only to prevent damage to      environmental impact assessment.
these ecosystems, but to reduce future shoreline damage     11 Monitor the progress and impact of recon-
if channels through the reef do indeed increase           struction.
vulnerability to flooding. Environmental impact assess-     12 Disseminate good practices and lessons learnt
ment legislation, now in place in most countries, must be      as they emerge.
enforced as a matter of urgency.
    The ICM approach is fully recognized in the 12    Marine protected areas
guiding principles that were drawn up at a meeting in    There is growing evidence that reefs within MPAs recover
Cairo in February 2005 by the UNEP Asian Tsunami       faster from catastrophes than those that are unprotected.
Disaster Task Force, in collaboration with the UNEP Co-   The abundant fish populations in Hikkaduwa National
ordination Office of the Global Programme of Action for   Park, Sri Lanka, showed little change as a result of the
the Protection of the Marine Environment from Land-     2004 tsunami, although unprotected reef sites appear to
                               have suffered losses (MPA News, 2005). Reefs in the
based Activities and other organizations (UK Department
for Environment, Food and Rural Affairs, the Food and    Indian Ocean that were well managed or remote from
Agriculture Organization of the United Nations, the United  human impact tended to recover more rapidly from the
Nations Educational, Scientific and Cultural Organization,  1998 bleaching; reefs under anthropogenic stress
IUCN, and WWF). Known as the Cairo Principles, these are   recovered poorly, if at all (Wilkinson, 2004).
aimed at helping to ensure environmentally sound post-        Many more MPAs are needed. Currently, some 685
tsunami reconstruction programmes, and are being       protected areas contain mangroves, covering about 9 per
implemented through an Action Plan (UNEP/GPA, 2005).     cent of the total area of mangrove (Spalding et al., 1997),
                               and 660 MPAs contain coral reefs. There is no global
THE CAIRO PRINCIPLES                     estimate of how much reef is protected (Spalding et al.,
Overarching principle                    2001), but in the Caribbean an estimated 20 per cent of
  1 Reduce the vulnerability of coastal comm-        reefs lie within MPAs (Burke and Maidens, 2004). Many
   unities to natural hazards by establishing a      MPAs need to be larger and to be made part of carefully
   regional early warning system and applying       designed networks to ensure that connected ecosystems

                                                             In the front line

                                         Improved resilience and adaptive management
      Fig. 5: Management effectivenes of Caribbean
      MPAs (per cent)                            Natural disasters have affected humans and the
                                         environment since the beginning of time – but both have
                                         the ability to regenerate and adapt to the impact of such
                                         events and the new circumstances that may arise as a
                                         result of them. This capacity to absorb recurrent
                                         disturbances such as storms and floods is called
                                             Already two-thirds of the coastal disasters
                                         recorded each year are associated with extreme weather
                                         events. The growing populations on, and rapid
                                         development of, the coastal zone guarantee that we will
      Most marine protected areas urgently need improved
                                         see an increase in economic, social and environmental
      management. Of 285 MPAs assessed in the Caribbean in 2004, only
                                         damage in the future caused by the associated reduction
      6 per cent were considered to be effectively managed (Burke and
                                         in human and ecosystem resilience. The conventional
      Maidens, 2004).
                                         approach has been to try to reduce the damage and
                                         eliminate change but a new thinking is developing. A far
T Heeger

                                         better approach may be to promote the conditions that
                                         improve resilience and also learn to adapt to the resulting
                                         changes (Adger et al., 2005). Careful planning and
                                         adaptive management can greatly reduce the impact of
                                         large disturbances.
                                             The rapid response of global, regional and
                                         national monitoring programmes to the tsunami
                                         demonstrated their value in providing essential
                                         information for management. Guidelines for Rapid
                                         Assessment and Monitoring of Tsunami Damage to Coral
                                         Reefs were produced within ten days (ICRI/ISRS, 2005)
                                         and disseminated by the UNEP Coral Reef Unit to the
                                         various international and UN agencies conducting
                                         environmental assessments in the region. Expert surveys
                                         were also quickly initiated with assistance from the
                                         Global Coral Reef Monitoring Network (GCRMN) and the
      Mu Koh Surin National Park in Thailand, gazetted in 1981 and      regional Coral Reef Degradation in the Indian Ocean
      covering 135 km2, is an ICRAN demonstration site and has a good
                                         (CORDIO) programme.
      track record of effective management. The December 2004
      tsunami largely destroyed tourism and the park’s infrastructure on
      the islands, as well as sea gypsy villages, but there were no     FINANCING THE FUTURE
      fatalities. The coral reefs, which were especially healthy with high
                                         Reefs and mangroves clearly provide significant benefits
      biodiversity before the event (see above), were being surveyed at
                                         and services to humankind, many of which have a high
      the time of the tsunami, permitting first-hand accounts. Trees
                                         economic value. Governments, civil society and the
      were knocked onto the reefs, along with large amounts of
      sediment. A survey was carried out two months later and        private sector must recognize that, as with other benefits,
      remarkably little damage had occurred: reefs had an average of 75
                                         there is a price to be paid for maintaining these
      per cent live coral cover, and some had 90 per cent, the sediment
                                         ecosystems. The cost is, however, generally much lower
      had gone, and there were already signs of some coral regeneration
                                         than the benefit received.
      in damaged areas (Comley et al., 2005).
                                             Although costs are hugely variable depending on
      are protected (not only representative sites), as well as       the location, size and type of management, average
                                         annual operational management costs of US$775 per km2
      resilient ecosystems, such as reefs identified as resisting
      or recovering quickly from bleaching (Grimsditch and          have been estimated for MPAs (Balmford et al., 2004).
      Salm, 2005). This is essential if species dependent on         This is significantly less that the estimated global values
                                         of ecosystems: US$100 000-600 000 per km2 per year in
      different ecosystems at different stages of their life cycles
      are to be protected, and the full range of ecosystem          the case of reefs and possibly more for mangroves. Basic
      services maintained.                          annual operating costs for MPAs can be as low as

In the front line

Fig. 6: Area of the world’s coral reefs and mangroves lying within the waters of countries in relation to those
countries’ position on the UN Human Development Index (left) and their GDP per capita (right) (per cent)

Many of the world’s wealthiest nations have jurisdiction over reefs and mangroves, either in their own coastal waters or in those of their
territories. Over 30 per cent of the world’s reefs lie in countries that are classified as highly developed, with a GDP per capita of more than
US$9 000. Australia, France, New Zealand, the United Kingdom and the United States directly influence about 25 per cent of reefs and a
significant proportion of mangroves. Furthermore, most of these countries are either sources of tourists to reef countries or have other
strong economic links with them and potentially could provide much greater financial and technical support. A higher proportion of
mangroves are found in the poorer countries, but nevertheless more than 10 per cent are found in highly developed countries.

US$200 000-600 000, as in the case of Belize and the            have indicated, for example, that tourists are willing to
Seychelles (Lutchman, 2005).                        pay more than US$50 extra per holiday and divers US$25
    There are vast untapped sources of funds and            more per dive if these result in high-quality reefs
financing mechanisms, ranging from fishery and tourism           (Westmacott et al., 2000a; Burke and Maidens, 2004). It
revenues and taxes, to royalties and fees from offshore          seems a small price to pay for the future survival of these
mining and mineral exploitation, to voluntary donations          small, priceless ecosystems.
and government aid (Spergel and Moye, 2004). Studies

                                                                         A Cornish

                                                                   In the front line

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                                  In the front line
                              Shoreline protection and other
                                   ecosystem services
                             from mangroves and coral reefs

                      The tragic and devastating consequences of the Asian tsunami, December 2004 ,
                      and the hurricanes and cyclones of 2005 were a wake up call for the global
                      community, dramatically drawing attention to the dangers of undermining the
                      services that coastal ecosystems provide to humankind.

                      This report has gathered lessons that have been learned since these events that
                      will be relevant to future management of the coasts in the context of severe
                      weather events and other potential consequences of global warming. More than
                      ever it is essential to consider the full value of ecosystem services – that is the
                      benefits that people derive from ecosystems – when making decisions about
                      coastal development.

                      The publication aims to help decision and policy makers around the world
                      understand the importance of coastal habitats to humans, focusing on the role of
                      coral reefs and mangroves. As well as coastal protection, it also addresses the
                      huge range of other benefits provided by these ecosystems and the role that they
                      can play in coastal development and in restoring livelihoods for those suffering
                      from the effects of extreme events.

                                        United Nations Environment Programme
                                           P.O. Box 30552, Nairobi, Kenya
                                             Tel: +254 (0) 20 621234
                                             Fax: +254 (0) 20 623927

UNEP World Conservation Monitoring Centre
219 Huntingdon Road, Cambridge CB3 0DL,
                                                                 January 2006

United Kingdom                                UNEP-WCMC Biodiversity Series No 24
Tel: +44 (0) 1223 277314
Fax: +44 (0) 1223 277136                           ISBN: 92-807-2681-1
by David Bael last modified 26-01-2007 10:44

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