Review of international studies on the value of coastal wetlands and mangrove

35 Pages·2014·0.67 MB·English

Review
 of
 international
 studies
 on
 the

value
 of
 coastal
 wetlands
 and
 mangrove

ecosystem
 services

Project
 Activity
 2.7
 for
 the
 Project:

Developing
 a
 piloting
 model
 on
 payments
 for
 coastal
 wetland
 ecosystem
 services
 in
 Mui
 Ca

Mau
 National
 Park
 in
 the
 context
 of
 climate
 change
 contributing
 to
 poverty
 reduction
 in

local
 community

1
THIS DOCUMENT IS SPONSORED BY

Project
 sponsored
 by

The
 Swedish
 International
 Development
 Cooperation
 Agency
 in
 Vietnam

Project
 Partners

Biodiversity
 Conservation
 Agency,
 Vietnam
 Environment
 Administration,
 Ministry
 of

Natural
 Resources
 and
 Environment,
 Vietnam

Research
 Center
 of
 Forest
 and
 Wetlands,
 Vietnam

Forum
 for
 Reforms,
 Entrepreneurship
 and
 Sustainability,
 Sweden

This
 report
 prepared
 by

Scott
 Cole

EnviroEconomics
 Sweden
 Consulting
 (EES)

(www.eesweden.com)

With
 assistance
 from

Linus
 Hasselström,
 Enveco
 Environmental
 Economics
 Consultancy
 Ltd
 (www.enveco.se)

Ana
 P.
 Aponte,
 Daxam
 Sustainability
 Services
 (www.daxam.se)

Malin
 Niemi
 and
 Ulrika
 Stavlöt,
 FORES
 (www.fores.se)

Citation

BCA,
 FORES,
 FORWET
 (2013)
 Review
 of
 international
 studies
 on
 the
 value
 of
 coastal

wetlands
 and
 mangrove
 ecosystem
 services,
 Stockholm,
 Sweden

Project
 Team

Ulrika
 Stavlöt

Ana
 P
 Aponte

Scott
 Cole

Linus
 Hasselström

Daniel
 Engström
 Stenson

Nguyen
 The
 Dong

Huynh
 Thi
 Mai

Nguyen
 Chi
 Thanh

Nguyen
 Tuan
 Phu

Nguyen
 Tien
 Dung

Le
 Huu
 Phu

2
Contacts

Biodiversity
 Conservation
 Agency,

Vietnam
 Environment
 Administration,

Ministry
 of
 Natural
 Resource
 and
 Environment
 Management

No
 10,
 Ton
 That
 Thuyet
 Street,
 Cau
 Giay
 district,

Hanoi,

Vietnam

Tel.:
 +
 84
 4
 37956868
 Ext.3108

Forum
 for
 Reforms,
 Entrepreneurship
 and
 Sustainability

Bellmansgatan
 10

118
 20
 Stockholm,
 Sweden

Tel:
 +46
 08
 45
 22
 660

3
Abbreviations

BT
  Benefits
 Transfer

CE
  Choice
 Experiment

CVM
  Contingent
 Valuation
 Method

DE
  Defense
 Expenditures

ES
  Ecosystem
 Services

HCM
  Hedonic
 Cost
 Method

ha
  hectare

HH
  Households

NP
  National
 Park

NPV
  Net
 Present
 Value

PES
  Payments
 for
 Ecosystem
 Services

PFM
  Production
 Function
 Method

RP
  Revealed
 Preferences

SP
  Stated
 Preferences

TCM
  Travel
 Cost
 Method

TEV
  Total
 Economic
 Value

VND
  Vietnam
 Dong

WTA
  Willingness
 to
 Accept
 compensation

WTP
  Willingness
 to
 Pay

4
Table
 of
 Contents

1.
  Introduction
 ...............................................................................................................................
 6

1.1.
  Valuation
 of
 ecosystem
 services
 ................................................................................................
 6

1.2.
  Purpose
 of
 this
 report
 ...................................................................................................................
 8

1.3.
  Scope
 and
 method
 ..........................................................................................................................
 9

2.
  Economic
 methods
 for
 assessing
 Ecosystem
 Service
 values
 ..................................
 10

2.1.
  Primary
 economic
 valuation
 methods
 ..................................................................................
 10

2.2.
  Benefits
 transfer
 (BT)
 method
 .................................................................................................
 12

3.
  Ecosystem
 services
 provided
 by
 mangrove
 wetlands
 ...............................................
 14

3.1
 Raw
 materials
 and
 food
 ...................................................................................................................
 15

3.2
 Coastal
 protection
 .............................................................................................................................
 15

3.3
 Erosion
 control
 ...................................................................................................................................
 15

3.4
 Water
 purification
 ............................................................................................................................
 15

3.5
 Carbon
 sequestration
 ......................................................................................................................
 15

3.6
 Maintenance
 of
 habitat
 and
 biodiversity
 ..................................................................................
 16

3.7
 Tourism,
 recreation,
 education
 and
 research
 .........................................................................
 16

4.
  Values
 from
 the
 economic
 literature
 ..............................................................................
 16

4.1
 Raw
 materials
 and
 food.
 ..................................................................................................................
 17

4.2
 Coastal
 protection
 .............................................................................................................................
 19

4.3
 Erosion
 control
 ...................................................................................................................................
 19

4.4
 Water
 purification
 ............................................................................................................................
 19

4.5
 Carbon
 sequestration
 ......................................................................................................................
 20

4.6
 Maintenance
 of
 habitat
 and
 biodiversity
 ..................................................................................
 20

4.7
 Tourism,
 recreation,
 education
 and
 research
 .........................................................................
 21

4.8
 Summary
 ..............................................................................................................................................
 22

5.
  Discussion
 ................................................................................................................................
 27

5.1.
  Key
 insights
 from
 the
 economic
 valuation
 literature
 ......................................................
 27

References
 .......................................................................................................................................
 32

5
1. Introduction

The
 term
 Ecosystem
 Services
 (ES)
 is
 widely
 recognized
 as
 a
 way
 to
 frame
 society’s

dependence
 on
 the
 planet’s
 ecosystems.
 Several
 projects
 have
 operationalized
 the
 term,

including
 the
 United
 Nations
 Millennium
 Ecosystem
 Assessment
 (MA,
 2005)
 and
 The

Economics
 of
 Ecosystems
 and
 Biodiversity
 (TEEB,
 2010),
 and
 both
 have
 concluded
 that

ES
 are
 highly
 valuable
 to
 society.
 Despite
 the
 increasing
 awareness
 of
 the
 value
 of
 ES,

they
 are
 becoming
 increasingly
 scarce.
 Because
 many
 of
 the
 world’s
 ES
 remain

undervalued
 or
 are
 not
 properly
 recognized,
 the
 incentive
 to
 provide
 them
 is
 reduced,

which
 reduces
 the
 flow
 of
 ecosystem
 services.

Wetlands
 are
 known
 to
 be
 one
 of
 the
 most
 productive
 and
 biologically
 rich
 ecosystems

(Richardson,
 1995).
 They
 provide
 a
 variety
 of
 ecosystem
 services,
 such
 as
 habitat
 for
 fish

and
 shellfish,
 water
 purification
 and
 flood
 mitigation.
 These
 services
 are
 essential
 to

human
 well-­‐being
 and
 poverty
 alleviation
 (MA,
 2005).
 In
 many
 countries,
 including

Vietnam,
 mangroves
 provide
 critical
 ecosystems
 services
 to
 society.
 However
 since
 1980,

more
 than
 20%
 of
 the
 world’s
 mangrove
 has
 been
 destroyed
 –
 a
 total
 of
 3.6
 million

hectares.
 Asia
 has
 suffered
 the
 largest
 net
 loss
 of
 mangroves
 with
 a
 disappearance
 of
 1.9

million
 hectares
 due
 to
 changes
 in
 land
 use
 (FAO,
 2008).
 In
 Asia,
 shrimp
 farming
 has

accounted
 for
 41%
 of
 the
 deforestation
 over
 the
 past
 decades
 (Valiela
 et
 al.,
 2001).

In
 Vietnam,
 180,000
 ha
 of
 mangrove
 forest
 were
 lost
 during
 1985-­‐2005,
 with
 many
 being

replaced
 by
 aquaculture
 ponds
 (ISPONRE,
 2011).
 Since
 the
 1940s,
 80%
 of
 mangrove

forest
 has
 been
 lost
 in
 Vietnam
 (talkvietnam.com,
 2013).
 From
 a
 welfare
 perspective,
 one

can
 argue
 that
 policies
 should
 allocate
 land
 use
 in
 the
 way
 that
 provides
 society
 with
 the

greatest
 benefits
 (i.e.,
 a
 utilitarian
 approach
 seeks
 the
 “greatest
 good
 for
 the
 greatest

number”,
 see
 e.g.
 Perman
 et
 al.,
 2003,
 p.56).
 Such
 an
 approach
 would
 weigh
 the
 value
 of

healthy
 ecosystems
 –
 and
 the
 services
 they
 provide
 society
 -­‐-­‐
 against
 other
 socially

profitable
 alternatives,
 to
 determine
 an
 optimal
 use
 of
 land.
 Failure
 to
 do
 so
 may
 lead
 to

short-­‐term
 economic
 benefits
 from
 development,
 but
 result
 in
 long-­‐term
 welfare
 losses,

which
 may
 be
 magnified
 if
 environmental
 resources
 become
 scarcer
 in
 the
 future.

1.1. Valuation
 of
 ecosystem
 services

The
 valuation
 of
 ecosystem
 services
 is
 an
 anthropocentric
 concept,
 i.e.,
 it
 attempts
 to

capture
 the
 benefits
 that
 ES
 provide
 human
 beings
 (so-­‐called
 instrument
 values,
 see
 e.g.,

SAB
 2009).
 These
 are
 distinct
 and
 separate
 from
 possible
 intrinsic
 values
 associated
 with

the
 provision
 of
 ES.
 The
 instrumental
 values
 discussed
 in
 this
 report
 may
 be
 affected
 by

several
 local
 factors
 in
 and
 around
 Mui
 Ca
 Mau
 NP,
 which
 have
 certain
 implications
 for

how
 a
 benefits
 transfer
 would
 apply.
 These
 include:

• scarcity
 (if
 the
 ES
 is
 rare,
 its
 value
 increases
 all
 else
 equal);

• substitute
 sites
 (if
 similar
 ES
 are
 provided
 nearby,
 its
 value
 decreases,
 all
 else

equal);

6
• technology
 (if
 aquaculture
 practices
 improve,
 the
 value
 of
 the
 supporting
 ES
 will

increase,
 all
 else
 equal)

• local
 preferences
 or
 sociodemographic
 characteristics
 (if
 residents’
 demand
 for

certain
 services
 increases,
 so
 too
 will
 the
 value
 for
 these
 ES)

• time
 (individuals
 tend
 to
 value
 the
 loss
 or
 gain
 of
 an
 ES
 far
 into
 the
 future
 less

than
 if
 they
 were
 to
 occur
 in
 the
 present,
 all
 else
 equal.
 See
 e.g.,
 discounting
 in
 SAB

2009)

• human
 knowledge
 (improved
 understanding
 of
 how
 ES
 affect
 our
 human
 well-­‐
being
 may
 alter
 the
 value
 we
 assign
 to
 ES).

For
 example,
 all
 else
 equal,
 the
 availability
 of
 substitute
 recreational
 sites
 in
 the

surrounding
 area
 may
 reduce
 the
 recreational
 values
 provided
 by
 Mui
 Ca
 Mau
 NP.
 On
 the

other
 hand,
 the
 future
 development
 of
 infrastructure
 around
 Mui
 Ca
 Mau
 NP,
 together

with
 rising
 income
 levels
 and
 a
 shift
 in
 preferences
 toward
 outdoor
 recreation
 in

Vietnam,
 would
 increase
 ES
 values
 associated
 with
 recreation
 in
 the
 Park.

Estimating
 the
 economic
 value
 of
 ES
 is
 no
 easy
 task.
 The
 value
 of
 goods
 such
 as
 wood,

shrimps,
 fish,
 etc.,
 typically
 generate
 private
 financial
 gains
 to
 individuals,
 whereas
 many

of
 the
 ES
 provided
 by
 mangroves
 produce
 services
 with
 “public
 good”
 characteristics

(Brander
 et
 al.,
 2012),
 i.e.
 those
 who
 benefit
 from
 the
 service
 cannot
 be
 excluded
 from

receiving
 the
 services,
 and
 the
 level
 of
 consumption
 by
 one
 beneficiary
 does
 not
 hinder

others
 from
 receiving
 the
 same
 level
 of
 the
 service.
 For
 example,
 mangrove
 provides
 a

number
 of
 public
 good
 type
 ES,
 such
 as
 protection
 against
 floods
 and
 hurricanes,

protection
 against
 shoreline
 and
 riverbank
 erosion,
 maintenance
 of
 biodiversity,
 climate

regulation,
 etc.
 (See
 e.g.
 Rönnbäck,
 1999,
 Barbier
 et
 al.,
 2011).
 However,
 many
 of
 these
 ES

values
 are
 non-­‐market,
 i.e.
 not
 captured
 by
 markets,
 and
 thus
 hard
 to
 see
 in
 short-­‐run

financial
 terms,
 see
 Section
 2.1.

There
 are
 several
 frameworks
 available
 for
 categorizing
 ES
 values.
 A
 common

framework
 that
 encompasses
 these
 is
 TEV
 (Total
 Economic
 Value).
 The
 framework

provides
 a
 systematic
 tool
 for
 considering
 the
 full
 range
 of
 impacts
 that
 changes
 in
 the

environment
 has
 on
 human
 welfare.
 Considering
 only
 instrumental
 value,
 the
 TEV
 of
 an

ecosystem
 service
 can
 be
 broadly
 divided
 between
 use
 values
 and
 non-­‐use
 values.
 (Pearce

et
 al.,
 2006).

• Use
 values
 can
 further
 be
 divided
 into
 direct
 use
 and
 indirect
 use
 values,
 where

direct
 use
 value
 refers
 to
 values
 associated
 with
 direct
 consumption
 or
 the
 values

related
 to
 the
 production
 of
 market
 goods,
 such
 as
 wood
 used
 for
 fuel
 and

building
 purposes
 and
 indirect
 use
 value
 refers
 to
 values
 provided
 by
 the

underlying
 functions
 of
 the
 ecosystem
 (e.g.,
 climate
 regulation
 or
 maintenance
 of

biodiversity).

• Non-­‐use
 values
 encompass
 existence,
 passive
 use
 and
 bequest
 values.
 An

existence
 value
 can
 be
 found
 when
 people
 are
 willing
 to
 make
 economic
 sacrifices

to
 preserve
 a
 healthy
 environment
 regardless
 of
 whether
 they
 themselves
 are

using
 or
 visiting
 this
 particular
 environment.
 They
 are
 experiencing
 improved

welfare
 from
 knowing
 that
 the
 environment
 is
 in
 a
 good
 state
 and
 would

7
experience
 a
 welfare
 loss
 if
 the
 environment
 is
 degraded.
 Analogously,
 a
 passive

use
 value
 can
 be
 found
 when
 people
 are
 willing
 to
 make
 economic
 sacrifices
 to

preserve
 an
 environment
 that
 they
 may
 consider
 using
 or
 visiting
 in
 the
 future.

The
 term
 bequest
 value
 refers
 to
 the
 values
 associated
 with
 preserving
 a
 healthy

environment
 for
 future
 generations.

This
 report
 uses
 the
 terms
 direct
 values
 (which
 refers
 to
 direct
 use
 values
 as
 defined

above)
 and
 indirect
 values
 (which
 refers
 to
 indirect
 use
 values
 as
 defined
 above).

Further,
 we
 also
 consider
 non-­‐use
 values
 as
 defined
 above.
 Typically,
 the
 direct
 values

can
 be
 estimated
 using
 market
 prices,
 whereas
 indirect
 values
 and
 non-­‐use
 values

require
 other
 valuation
 methods
 (as
 is
 further
 explained
 in
 Section
 2),
 since
 they
 are

typically
 not
 reflected
 in
 market
 transactions.
 .The
 lack
 of
 markets
 to
 reveal
 indirect

values
 often
 leads
 to
 the
 misperception
 that
 these
 values
 are
 less
 important
 and,
 as
 such,

are
 frequently
 left
 out
 of
 the
 policy-­‐making
 process.
 To
 the
 contrary,
 indirect
 values
 may

represent
 a
 significant
 portion
 of
 the
 TEV
 (see
 e.g.,
 Ranganathan
 2008)

The
 Vietnamese
 government
 has
 recognized
 the
 value
 of
 the
 country’s
 ecosystems
 and
 is

pursuing
 legal
 and
 market-­‐based
 approaches
 to
 environmental
 protection,
 with
 a

strategic
 focus
 on
 ES
 such
 as
 biodiversity
 conservation.
 The
 Vietnamese
 wetlands
 play
 an

important
 role
 for
 local
 people
 and
 the
 socioeconomic
 development
 of
 the
 country

(Vietnam
 EPA,
 2005),
 and
 are
 in
 need
 of
 protection.

1.2. Purpose
 of
 this
 report

The
 study
 area
 for
 our
 project
 is
 the
 Rehabilitation
 area
 in
 the
 Mui
 Ca
 Mau
 National
 Park

in
 southern
 Vietnam
 (See
 Figure
 1
 in
 Daxam
 2013).
 The
 area
 is
 well-­‐renowned
 for
 its

viable
 mangrove
 wetlands,
 which
 provide
 a
 number
 of
 valuable
 ES.
 This
 project
 focuses

on
 three
 human
 activities
 in
 the
 area1
 that
 depend
 on
 the
 variety
 of
 ES
 provided
 by

mangrove
 wetlands:
 (1)
 Shrimp
 farming,
 (2)
 Agroforestry,
 and
 (3)
 Homestay
 and

associated
 tourist
 experience.
 Given
 anticipated
 future
 growth
 in
 these
 human
 activities,

there
 is
 a
 need
 for
 guidance
 on
 how
 to
 manage
 this
 growth
 sustainably.
 All
 these

activities
 are
 potentially
 conflicting
 with,
 and/or
 dependent
 on,
 mangrove
 preservation.

Households
 in
 Mui
 Ca
 Mau
 are
 dependent
 on
 their
 ponds
 for
 shrimp,
 crab
 and
 clam

production.
 These
 ponds
 may
 compete
 with
 mangrove
 for
 space.

 However,
 the

productivity
 in
 the
 ponds
 is
 also
 dependent
 on
 mangrove.
 Falling
 leaves
 from
 trees
 at
 the

pond’s
 edges
 serve
 as
 a
 source
 of
 food
 that
 maintains
 a
 productive
 ecosystem
 in
 the

ponds.
 Agroforestry
 may
 also
 compete
 with
 mangrove
 for
 space.
 Concerning
 homestay,
 it

is
 likely
 to
 be
 dependent
 on
 a
 healthy
 mangrove
 ecosystem
 since
 tourists
 with
 an
 interest

in
 nature
 may
 choose
 their
 destination
 based
 on
 how
 healthy
 the
 ecosystem
 is
 in
 the
 area.

Information
 on
 the
 values
 provided
 by
 mangrove
 in
 the
 area
 may
 support
 decision-­‐
making
 concerning
 these
 three
 activities,
 while
 also
 improving
 society’s
 awareness
 of
 ES

in
 general.
 Further,
 a
 system
 for
 Payments
 for
 Ecosystem
 Services
 (PES)
 is
 being

suggested
 in
 the
 rehabilitation
 area.
 Information
 on
 ES
 values
 is
 particularly
 important
 in

1
 The
 motivation
 for
 focusing
 on
 these
 activities
 is
 the
 need
 to
 test
 this
 approach
 to
 sustainable

environmental
 management
 through
 a
 pilot
 study.
 If
 successful,
 the
 pilot
 study
 may
 be
 expanded
 to
 cover

other
 ecosystem
 service-­‐dependent
 human
 activities.

8
this
 context
 since
 it
 provides
 a
 basis
 for
 the
 design
 of
 such
 a
 system
 (Moran
 and
 Phuong,

2012).
 Therefore,
 this
 study
 considers
 all
 relevant
 the
 values
 provided
 by
 ES
 in
 the
 area,

rather
 than
 just
 those
 that
 support
 the
 three
 human
 activities
 in
 focus
 in
 this
 pilot
 study.

This
 report
 aims
 at
 providing
 a
 deeper
 understanding
 of
 the
 values
 at
 stake
 connected
 to

mangrove
 wetlands
 in
 Mui
 Ca
 Mau,
 with
 a
 primary
 focus
 on
 the
 indirect
 values
 that

mangroves
 provide.
 The
 report
 aims
 to
 shed
 light
 on
 these
 indirect
 values
 and
 how
 they

may
 inform
 a
 future
 PES
 structure
 in
 the
 study
 area.

1.3. Scope
 and
 method

This
 report
 relies
 on
 a
 method
 called
 benefits
 transfer
 (See
 Section
 2.2),
 which
 reviews

mangrove
 valuation
 estimates
 in
 the
 economic
 literature
 and
 considers
 the

appropriateness
 of
 transferring
 these
 values
 to
 the
 study
 area
 (Mui
 Ca
 Mau).
 Based
 on

the
 available
 literature,
 we
 attempt
 to
 highlight
 the
 value
 of
 a
 preserved
 hectare
 of

mangrove
 in
 Mui
 Ca
 Mau
 based
 on
 the
 plethora
 of
 ES
 it
 provides.
 Because
 of
 the

challenge
 of
 this
 value
 transfer
 exercise
 we
 also
 suggest
 methods
 for
 future
 research.

To
 assess
 the
 relevant
 values
 at
 stake
 in
 the
 Mui
 Ca
 Mau
 study
 area,
 we
 have
 reviewed
 a

large
 literature
 related
 to
 the
 ES
 from
 mangrove
 wetlands
 and
 their
 estimated
 values.

Some
 of
 the
 estimates
 from
 other
 study
 sites
 capture
 changes
 in
 ES
 values
 that
 are
 very

similar
 to
 what
 may
 occur
 in
 Mui
 Ca
 Mau,
 but
 in
 other
 cases
 the
 estimates
 are
 less

relevant
 for
 our
 study
 area.
 For
 example,
 values
 are
 likely
 to
 be
 dependent
 on
 geography,

demography,
 existence
 of
 substitute
 sites,
 etc.
 The
 objective
 of
 a
 benefits
 transfer
 is
 to

sort
 through
 the
 existing
 literature
 and
 find
 studies
 that
 value
 an
 environment
 that
 is

sufficiently
 similar
 to
 the
 study
 site
 that
 the
 estimates
 themselves
 may
 help
 highlight
 the

values
 at
 stake
 in
 Mui
 Ca
 Mau.

The
 scope
 of
 this
 report
 is
 somewhat
 limited.
 We
 do
 not
 conduct
 a
 formal
 benefits

transfer,
 as
 that
 would
 require
 a
 more
 detailed
 analysis.
 Instead,
 our
 report
 identifies

some
 of
 the
 existing
 values
 and
 discusses
 their
 potential
 applicability
 and
 relevance
 to

our
 study
 area.
 Thus,
 the
 results
 of
 this
 report
 are
 not
 intended
 to
 provide
 policy
 makers

with
 specific
 values
 for
 use
 in
 a
 formal
 cost-­‐benefit
 analysis
 or
 damage
 assessment.

These
 values
 should
 rather
 be
 seen
 as
 a
 ”guide”
 that
 will
 help
 us
 develop
 prices
 for
 a
 PES

structure,
 where
 these
 prices
 are
 a
 function
 of
 several
 variables
 (e.g.,
 ability
 to
 pay,

equity/fairness,
 value
 to
 society,
 efficiency
 of
 resource
 use,
 etc.).
 Further,
 the
 report
 will

highlight
 key
 knowledge
 gaps
 concerning
 ES
 values
 in
 Mui
 Ca
 Mau.

When
 searching
 for
 literature,
 we
 have
 focused
 on
 studies
 that
 provide
 value
 estimates

for
 coastal
 wetlands,
 with
 a
 primary
 focus
 on
 mangrove.
 Because
 there
 are
 several

primary
 studies
 that
 examine
 coastal
 wetland
 values
 globally,
 the
 core
 part
 of
 this

analysis
 is
 based
 on
 studies
 that
 provide
 an
 overview
 or
 meta
 analysis
 of
 valuation

results,
 rather
 than
 on
 detailed
 existing
 case
 studies.
 Because
 value
 estimates
 of

mangrove
 ecosystems
 are
 highly
 context
 dependent,
 we
 have
 searched
 for
 studies
 that

have
 Southeast
 Asian
 or
 Vietnamese
 relevance.
 For
 example,
 in
 some
 parts
 of
 the
 world

mangrove
 forests
 (both
 native
 and
 non-­‐native)
 and
 their
 ecosystems
 have
 become
 so

abundant
 that
 they
 have
 encroached
 upon
 salt
 marshes,
 which
 reduces
 the
 extent
 of
 the

latter
 habitat
 (Rogers
 et
 al
 2005).
 The
 mechanisms
 for
 this
 expansion
 are
 not
 entirely

9
known,
 neither
 are
 the
 consequences
 for
 human
 well-­‐being
 in
 these
 areas
 where

mangroves
 have
 displaced
 salt
 marsh.
 The
 fact
 that
 mangroves
 provide
 clear
 benefits
 to

local
 human
 populations
 in
 Mui
 Ca
 Mau
 underscores
 the
 importance
 of
 understanding

local
 ecological
 conditions
 in
 a
 valuation
 context.

In
 Section
 2,
 we
 provide
 a
 brief
 overview
 of
 economic
 valuation
 methods
 for
 assessing
 ES.

Section
 3
 identifies
 ES
 that
 are
 provided
 by
 mangrove
 wetlands.
 Section
 4
 presents
 value

estimates
 from
 the
 literature,
 and
 Section
 5
 concludes
 by
 discussing
 the
 applicability
 of

these
 values
 to
 Mui
 Ca
 Mau
 as
 well
 as
 key
 lessons
 learned
 for
 future
 ES
 valuation
 in
 the

area.

2. Economic
 methods
 for
 assessing
 Ecosystem
 Service
 values

People
 are
 affected
 by
 the
 supply
 of
 ES.
 They
 provide
 goods
 and
 services
 that
 improve

well-­‐being
 for
 individual
 consumers
 and
 they
 provide
 inputs
 for
 production,
 which

provides
 profits
 for
 firms.
 A
 change
 in
 the
 provision
 of
 ecosystem
 services
 will
 therefore

affect
 well-­‐being
 and
 profits.
 An
 important
 task
 for
 environmental
 economists
 is
 to

assess
 the
 size
 of
 benefits
 and
 costs
 due
 to
 environmental
 change
 and,
 where
 possible,
 to

express
 these
 in
 monetary
 terms
 with
 the
 help
 of
 economic
 valuation
 methods.
 The

purpose
 of
 this
 section
 is
 to
 briefly
 explain
 the
 primary
 economic
 valuation
 methods2

available
 for
 monetizing
 these
 impacts
 (Section
 2.1)
 and
 to
 describe
 the
 approach
 used

here
 called
 benefits
 transfer
 (Section
 2.2).
 A
 more
 detailed
 exposition
 can
 be
 found
 in

Freeman
 (2003)
 or
 Pearce
 et
 al.
 (2006).

2.1. Primary
 economic
 valuation
 methods

Valuing
 environmental
 changes
 economically
 is
 theoretically
 about
 analyzing
 the
 trade-­‐
offs
 individuals
 are
 prepared
 to
 make
 between
 the
 environment
 and
 other
 resources.

Economic
 theory
 suggests
 that
 such
 trade-­‐offs
 reveal
 the
 influence
 that
 environmental

changes
 have
 on
 human
 well-­‐being.
 In
 other
 words,
 economists
 measure
 the
 influence
 of

an
 environmental
 change
 on
 well-­‐being
 as
 the
 resources
 individuals
 would
 be
 willing
 to

give
 up
 for
 having
 the
 change
 (or
 preventing
 the
 change).
 Another
 word
 for
 this

willingness
 to
 give
 up
 resources
 is
 willingness
 to
 pay
 (WTP).
 In
 some
 situations
 it
 is
 more

relevant
 to
 study
 another
 kind
 of
 trade-­‐off,
 namely
 what
 people
 require
 as
 compensation

2
 Our
 study
 focuses
 only
 on
 economic
 valuation
 studies,
 which
 necessarily
 excludes
 other
 potentially
 valid

concepts
 of
 human
 value.
 Economic
 values
 reflect
 an
 underlying
 assumption
 that
 individuals
 face
 trade-­‐offs

between
 the
 consumption
 of
 goods
 (private
 or
 non-­‐market)
 and
 that
 the
 measurement
 of
 these
 trade-­‐offs
 -­‐
-­‐
 in
 monetary
 or
 non-­‐monetary
 terms
 –
 form
 the
 basis
 of
 economic
 values.
 SAB
 (2009)
 discusses
 the

possibility
 of
 using
 an
 "integrated
 and
 expanded"
 concept
 of
 value
 for
 analyzing
 environmental
 decision-­‐
making
 that
 categorizes
 two
 fundamentally
 different
 approaches
 to
 valuation
 (see
 Table

 1,
 p.
 14
 in
 SAB

2009):
 (1)
 preference-­‐based
 values,
 in
 which
 "Human
 preferences
 directly
 determine
 all
 of
 the
 concepts
 of

value”
 (p.
 15).
 These
 includes
 economics
 values
 in
 addition
 to
 attitudes
 or
 judgments,
 community-­‐based

values,
 and
 constructed
 preferences;
 and
 (2)
 biophysical
 values,
 in
 which
 “values
 reflect
 the
 contribution
 of

ecological
 changes
 to
 a
 pre-­‐specified
 biophysical
 goal
 or
 standard
 identified
 or
 set
 prior
 to
 measuring
 the

contribution
 of
 those
 changes.”
 (p.
 15).
 These
 include
 bio-­‐ecological
 values
 and
 energy-­‐based
 values.

However
 the
 same
 document
 cautions
 against
 potential
 problems
 with
 non-­‐economic
 valuation

approaches
 (e.g.,
 validity,
 double-­‐counting,
 aggregation,
 etc).

10