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Species conservation review

       Economic Linkages Between Coastal Wetlands
           and Habitat/Species Protection:
   A Review of Value Estimates Reported in the Published Literature




                   Prepared by

               Richard F. Kazmierczak, Jr.
          Associate Professor of Environmental Economics
         Department of Agricultural Economics & Agribusiness
          Louisiana State University Agricultural Center
             Baton Rouge, Louisiana 70803-5604

    http://www.agecon.lsu.edu/faculty_staff/IntroFacPages/kazmierczak.htm




Natural Resource and Environment Committee             Staff Paper 2001-04
LSU Agricultural Economics & Agribusiness                   May 2001
    Economic Linkages Between Coastal Wetlands and Habitat/Species Protection:
      A Review of Value Estimates Reported in the Published Literature

                     Richard F. Kazmierczak, Jr.
                 Louisiana State University Agricultural Center


                           Summary

     This manuscript summarizes a total of 8 peer-reviewed studies,1 published from 1975 to 2001,
reporting 24 separate estimates for the disaggregate2 value of habitat and species protection services
provided by coastal and non-coastal wetlands. Estimates varied within a single order of magnitude and
were fairly tightly bounded. Considering only coastal zone wetlands across all study categories, the value
of habitat and species protection ranged from $168.96/acre/year to $403.16/acre/year, with a mean and
median of $249.44/acre/year and $253.47/acre/year, respectively.3, 4 By comparison, reported estimates
of willingness-to-pay (WTP) values for wetland habitat and species protection services ranged from a low
of $30.12 to $434.67, with a mean and median of $211.59 and $213.86, respectively. Geographic
location and type of wetland appeared to have a relatively minor impact on the estimated values.


                          Introduction

     Coastal wetlands are increasingly recognized as essential to natural systems and human activities
because of the environmental services that they provide. However, this recognition has not resulted in
capitalized economic value for landowners (Heimlich et al. 1998). Nonmarketed wetland benefits may be
important to society, but the lack of a market value for the services means that they are often de-
emphasized relative to physical loss or the private economic gains that can arise from conversion of
wetlands to other land uses (van Vuuren and Roy 1993). While the search for quantitative measures of
wetland values is challenging due to the diversity, socioeconomic context, and complex hydro-biological
functions of wetlands (Scodari 1990), informed policy requires that both market and nonmarket wetland
values be incorporated into the decision making process.

    One of the most important, but nonmarketed, services provided by coastal wetlands is habitat and
species protection, and in particular the provision of reproductive habitat for threatened and endangered
species. Wetland preservation efforts began early in the last century out of concern for waterfowl habitat
when President Roosevelt established the first National Wildlife Refuge in 1903 to protect Pelican Island,

1
  To the author’s knowledge this represents all the peer-reviewed published studies that explicitly seek to value the
linkage between wetlands and water quality/purification services.
2
  From a theoretical economic perspective, the services provided by wetlands generally should not be disaggregated
and valued separately due to the potential for double counting and offsetting effects (see Pendleton and Shonkwiler
[2001] for a discussion of this in a different context). For example, the provision of water purification services may,
in many cases, simultaneously provide for increased habitat and species protection. Valuing each of these services
separately (when, in fact, they are inseparable) and summing will lead to overestimating total potential wetland
value.
3
  All values in year 2000 dollars (see Table 1).
4
  In a partial review of wetland valuation studies, Heimlich et al. (1998) calculated a much broader range on the per
acre value estimates, in part because they considered the provision of a number of different services besides water
quality, but also because they converted household and individual willingness-to-pay (WTP) values to per acre
values using various assumptions not necessarily contained in the original studies. The review presented in this
manuscript does not take this approach, and instead lists the WTP values separately (if not originally presented on a
per acre basis) for comparison purposes.


                             1
a nesting site for colonial water birds. The Migratory Bird Hunting Stamp Act of 1934 established a
special fund to finance wetlands acquisitions for duck habitat. In 1961, the Wetlands Loan Act allowed
advanced appropriations for the purchase of wildlife refuges and waterfowl production areas (National
Aududon Society 1996), leading to the current National Wildlife Refuge system that contains over 500
refuges and nearly 200 Waterfowl Protection areas (Stewart 1996). Recent legislative and administrative
efforts to protect wetlands and the critical habitat that they encompass include the 1970 Water Bank
program, Section 404 of the Federal water Pollution Control Act Amendments of 1972, Executive Order
11990 issued by President Carter in 1977, the Small Wetlands Acquisition program of the U.S. Fish and
Wildlife Service, “Swampbuster” provisions in the 1985 Food Security Act, and the Wetland Reserve
Program (Heimlich et al. 1998). Most of these programs and polices were implemented without any
explicit consideration of the economic benefits associated with habitat and species protection.

     This report documents the current status of knowledge concerning the economic value of the
habitat and species protection services generated by coastal and other wetlands. In particular, studies that
focus on valuing habitat and species protection services as an unbundled product of wetland function are
highlighted.5 A brief overview of the economic linkages between wetland ecosystems and habitat/species
protection is first presented, thus providing a basic framework for understanding why specific variables
and measurement methods are of interest. Second, the common methods used to value the habitat and
species protection services of wetlands are outlined, along with their major advantages and disadvantages.
This information can help the reader evaluate the usefulness of any particular estimate. Next, the results
of individual valuation studies are presented and summarized. Lastly, the report concludes with a
complete list of the literature cited.


           Relationship Between Wetlands and Habitat/Species Protection

     Policymakers face complex, multi-objective trade-offs when attempting to develop strategies for
coastal restoration and protection.6 Implementation of any specific strategy will result in benefits and
costs that will, in general, be different than those experienced under alternative strategies. Economics can
be used to help inform policymakers about the relative benefits and cost of different strategies, but
analysts require information on (1) the relationship between anthropogenic activities and coastal wetland
loss, (2) the costs imposed on society from coastal wetland loss, and (3) the costs of taking action to
prevent coastal wetland loss. In the typical environmental management scenario, human activities are
considered to be a cause of degradation, and the management of these activities via regulation or the use
of economic instruments has the goal of reducing environmental impacts. Changing established human
activities is potentially costly, and the cost will vary by the specific type of activity and its
interrelationship with the environment. While some Louisiana coastal wetland loss can be attributed to
traditional human industrial, municipal, and agricultural activities, natural environmental processes on a
regional, hemispheric, and global scale are also important. Complicating the identification of causal
linkages and their importance to habitat and species protection is the heterogeneity of existing wetlands.
Some wetlands perform many functions, but some may perform few or even none. In addition, many of
the environmental services are generated simultaneously in varying degrees by the same wetland function.
From this perspective, the habitat and species protection services of wetlands can best be understood as
part of an economic joint product. This jointness-in-products creates difficulties in measuring the
economic importance of specific wetlands functions, and as a result the literature contains a limited


5
  A substantial part of the wetland valuation literature attempts to measure the theoretically correct multi-product
value of wetlands and not the individual service components. An overview of the results generated by these studies
is presented in the report (Table 2) for comparison to the single-product water quality value estimates.
6
  The following discussion was adapted from Keithly and Ward (2001) and Heimlich et al. (1998).


                             2
number of empirical studies that isolate the habitat and species protection benefits associated with
wetland integrity.

     Abstracting from the technical measurement difficulties, there a number of general benefits that
accrue to society from its interaction with any large-scale ecosystem such as coastal wetlands (Pearce and
Turner 1990). Ecosystems supply both stock and flow resources that can be used as direct and indirect
inputs to production and consumption activities, thereby generating productivity and growth in the overall
economic system. While the resources can be either renewable or nonrenewable, goods and services
provided by Louisiana’s coastal wetlands (and their associated marine ecosystems) are generally
considered renewable resources.7 The provision of habitat and species protection services via ecological
support processes can be considered one of these renewable resources.

     Wetlands are the most biologically productive ecosystems in the temperate regions, rivaling
tropical rain forests (Mitsch and Gosselink 1993). Their biological productivity derives from an ability to
recycle nutrients and energy, and provide habitat for living organisms.8 Some fish and wildlife species
spend their entire lives in wetlands and others using them intermittently for feeding or reproduction.
Amphibians and reptiles also depend on wetlands, and are particularly sensitive to wetland degradation.
In addition, over one-third of all bird species in North America rely on wetlands for migratory resting
places, breeding or feeding grounds, or cover from predation (Kroodsma 1979). Many larger animals,
such as muskrat, beaver, otter, mink, and raccoon prefer wetlands as their habitat, and wetland habitats
are critical for the survival of a number of threatened and endangered species. The linkage of these
habitat-related biophysical functions with economic value comes from the nonconsumptive, nonmarket
value of the species and the nonmarket value of wetland aesthetics. This nonmarket orientation
complicates wetlands policy because the habitat services rendered by wetlands are public goods whose
benefits accrue to society at large, not specifically to wetland owners. As a result, many private wetland
owners may find it more profitable to convert wetlands to alternative uses or abandon its maintenance
altogether.

     Once the conceptual benefits of an ecosystem are identified, economic values need to be assigned
to these benefits. Having these assigned values allows policy makers to quantitatively assess the
economic benefits that society might gain from marginal improvements in the integrity of the ecosystem.
Value is associated with the amount that society (both current and future generations) would be willing to
pay for the economic system characteristics (primarily the services and attributes) provided by the
ecosystem if they were not provided free of charge. The greater the benefits derived from the services
provided by any particular ecosystem, the more that ecosystem is valued by society. In general, the value
of these services tends to be positively related with the integrity of the ecosystem. Of course, any action
taken to decrease the loss of Louisiana’s coastal wetlands, and thus increase the welfare of society at
large, comes with a cost. These costs must be weighed against the benefits to determine, from the criteria
of welfare economics, whether action is warranted, and to what extent.




7
 While significant nonrenewable mineral extraction, and the related economic activity, takes place in coastal
Louisiana and the adjacent continental shelf, to a large extent its continued existence is not dependent on
maintaining the integrity of the coastal wetlands. The extraction industry’s cost structure may change if coastal
wetlands are lost, but not likely to the extent that they would become economically infeasible. Navigation and port
activities, however, are more likely to be negatively affected by the loss of coastal wetlands.
8
  And thus the joint-product link between habitat/species protection and the water quality services of wetlands.


                             3
                       Valuation Methods

     The total economic value of a wetland area is the sum of the amount of money that all people
who benefit from the wetland area would be willing to pay to see it protected (Whitehead 1992). If this
definition of wetland value is to be empirically viable, individuals that benefit must (1) realize that they
benefit, (2) understand the full extent to which they benefit, and (3) be capable of placing a dollar value
on the level of their benefits, either through reference to market-based prices or some alternative,
nonmarket pricing system. Methods for valuing the stock of natural capital assets and service flows
generated by wetlands have been extensively discussed in both the published and unpublished literature.9
While philosophical debate has occurred over the ability to empirically measure the full range of benefits
that flow from an environmental resource, economists generally agree that accurate measurement is
possible if valuation studies are carefully conducted (U.S. Department of Commerce 1993). In fact,
review of past nonmarket valuation studies suggests that previously perceived variability and unreliability
in the estimated values does not actually exist, particularly if one controls for the varying characteristics
of the resources being valued and the way in which the estimated values are presented (Carson et al.
1996). Thus, published value estimates might be useful in analyzing the economic impact of Louisiana's
coastal wetlands as long as careful attention is given to the details of the study and the resources being
valued.10

     Four theoretically plausible valuation methods have been used in the neoclassical economic
literature to place valid dollar values on wetland resources.11 These methods are the net factor income
(NFI) method, the contingent valuation method (CVM), the travel cost method (TCM), and the hedonic
price method (HPM). A fifth set of methods found in the literature, but not theoretically valid under
typical application, is the damage cost or replacement cost methods (DCM or RCM). All of these
methods are briefly described below. In addition, the non-neoclassical literature, as well as the biological
literature, often contains studies employing energy analysis methods (EAM), whereby the value of
ecosystem assets are directly related to their energy processing abilities.12 Shabman and Batie (1978)
detailed the fundamental problems and economic fallacies imbedded in this approach,13 and no further
discussion of its use is included in this report. The results from two studies employing EAM, however,
are reported in Table 2 in order to completely characterize the wetland valuation literature.

    The NFI method uses market prices to measure the additional profit earned by firms due to the
contribution of the wetlands to production activities, and it generates use values. Thus, the NFI method is

9
  For excellent early overviews, see Greenley et al. (1982) and Amacher et al. (1989). Scodari (1990) provides a
thorough review of the advantages and disadvantages of various methods specifically within a wetland valuation
context, while Whitehead (1992) contains a lucid, if somewhat terse, review of the methods and the theory behind
them. More recent papers detailing established and newer methods include Feather et al. (1995), Apogee Research,
Inc. (1996), Mahan (1997), Bockstael (1998) and Pendleton and Shonkwiler (2001). For comprehensive reviews of
the theory and application of contingent valuation methods for nonmarket goods and services, see U.S. Department
of Commerce (1993) and Bishop et al. (1998).
10
  This type of detailed examination was beyond the time constraints of this study, but it should be seriously
considered for inclusion in future phases of a valuation project.
11
  The brief methods discussion borrows from Amacher et al. (1989), Whitehead (1992), and others.
12
  This approach, which first received widespread publicity and policy attention due to a study by Gosselink et al.
(1974), is based on the Odum and Odum (1972) contention that society's use of resources should maximize the net
energy production of the total environment (including its natural and developed components).
13
  The fundamental problem is that EAM fails to recognize the nature of the process by which economic values are
determined, and makes an "illegitimate marriage" of the principles of systems ecology with economic theory
(Shabman and Batie 1978). "This leads to estimates of marsh service value that are, at best, inaccurate. At worst,
these inaccurate estimates may capture the focus of policy debate, and hinder, rather than improve, the resource
management process for coastal wetlands."


                             4
most appropriate when the wetland provides a service that leads to an increase in producer surplus, or the
economic gains attained by the users of the resource, because it exploits the relationship between the
value of the production activity and the wetland acreage. In the NFI method the physical relationship
between wetland areas and the economic activity is empirically estimated from data on the production
activity. It is then possible to identify the increase in producer surplus (economic gain) associated with
the use of the wetland resource.14 If the empirical estimates are obtained through statistical regression,
then estimates of the marginal value product (MVP) of the wetland resource can be generated. In this
context, the MVP provides a direct measure of the firm owner's willingness-to-pay to avoid wetland
degradation.

     Producer surplus generated by the use of a wetland can also be estimated using the RCM. This
approach values the wetland=s service based on the price of the cheapest alternative way of obtaining that
service. For example, the value of a natural wetland in the treatment of wastewater might be estimated
using the cost of chemical, mechanical, or constructive alternatives. The use of RCMs needs to be
governed by three considerations (Shabman and Batie 1978): (1) the alternative considered should
provide the same services, (2) the alternative selected for cost comparison should be the least-cost
alternative, and (3) there should be substantial evidence that the service would be demanded by society if
it were provided by that least-cost alternative. Taken together, these condition differentiate RCM from
the more general class of DCMs, where the entire value of a marketable good or service is tied to the
preservation of a wetland resource, ignoring consumer and producer substitution possibilities. Even with
restrictive application, the RCM can only be considered to yield an upper bound on the true WTP for the
wetland service because the producer may not choose to actually use the alternative considered (Anderson
and Rockel 1991).

     The CVM is a survey approach that measures the total economic value of all wetland goods and
services by directly asking individuals about their WTP. The CVM establishes a hypothetical market by
providing information about wetland resources, specifying payment rules and vehicles, and posing
valuation questions. Answers to these questions can be used to directly measure WTP, and CVM may be
the only way to estimate many non-use values of environmental resources. But, in order for CVM to
yield valid economic measures, study participants must be both willing and able to reveal their values.
Other valuation approaches, such as TCM and HPM discussed below, depend on revealed preferences
through market transactions and other behavior. Statements from economic actors about how they would
act under hypothetical circumstances, as used in the CVM, are a very different measure and ultimately
need to assessed for validity (Bishop et al. 1998). A panel of experts organized by the National Oceanic
and Atmospheric Administration (NOAA) of the U.S. Department of Commerce, and co-chaired by
Nobel laureate economists Kenneth Arrow and Robert Solow, concluded that (1) there is too much
positive evidence to dismiss CVM and its usefulness in providing information about values, (2) CVM
studies do not automatically generate value information, but are highly dependent on the content validity
of the survey, and (3) CVM is an evolving market valuation technique (U.S. Department of Commerce
1993). In the words of the panel (p. 4610), “CV studies convey useful information. We think it is fair to
describe such information as reliable by the standards that seem to be implicit in similar contexts, like
market analysis for new and innovative products and the assessment of other damages normally allowed
in court proceedings . . . . Thus, the Panel concludes that CV studies can produce estimates reliable
enough to be a starting point of a judicial process of damage assessment, including lost passive-use
values.”

    The TCM approach is often used to measure the recreational benefits of wetlands, but it is
generally applicable to valuing any nonmarket wetland good or service that individuals are willing to

14
  In practice, it is often assumed that the demand for the good being produced by the user is perfectly elastic, and
thus changing wetland services has no effect on consumer surplus.


                              5
travel to and use at the wetland site. The TCM method estimates the costs incurred traveling to visit and
use the site, with the concept being that the travel and time costs are measures of implicit market prices.
The estimated costs are then used to construct demand functions that use travel and time costs as
independent variables.15 Consumer surplus per recreation trip and year can then be approximated from
the estimated demand curve. The application of TCM assumes that (1) users have identical utility
functions for the activity, and thus will have identical demand functions, (2) users are indifferent between
incurring costs as user fees or travel costs, (3) weak complimentarity holds in that changes at competing
sites do not affect use at the site being valued, and (4) site use is not congested. Given these assumptions,
TCMs cannot be used to value nonmarket goods and services that either do not require the user to visit the
site or that are offsite products. Furthermore, TCM generally cannot account for multiple sites, visits to
multiple sites on the same trip, or the impact of small resource changes on user perceptions and travel
patterns.

     The HPM has been used to measure the contribution of wetlands for flood control and the role of
wetland aesthetics in housing and property prices. Thus, HPMs attempt to tie wetland service value
directly to a market price (Freeman 1998). In a market at equilibrium, land values and land rents should
be a function of land characteristics, including the proximity to and services provided by wetlands. The
increment to the land or housing price arising from wetland services is a measure of the implicit price of
that service. There are three key assumptions required to apply HPM to estimate the wetland contribution
to land values. First, there must be data on a continuum of sites with varying wetland characteristics and
acreage. Second, purchasers and sellers of wetland parcels are assumed to have access to the same
information regarding the condition of the site and the nature and use of the wetland. Third, wetland
purchasers (or purchasers of property near wetlands) are assumed to have identical preferences for
wetland characteristics. The assumption of identical preferences makes estimation of demand curves
possible when data does not exist about individual preferences.

     The valuation method employed in any particular habitat and species protection valuation study
depends primarily on the ability to quantitatively discern the biophysical linkages between characteristics
of a particular wetland area and the potential changes in the quality and quantity of habitat for a given
species. Given that this relationship is often poorly understood from a quantitative perspective, CVM
may be most appropriate valuation approach even in light of its limitations. No habitat/species protection
valuation studies were found that employed NFI, TCM, HPM, or RCM approaches.


                     Review of Estimated Values

     No estimates for the value of Louisiana wetlands in the provision of habitat and species
protection services were found in the published literature. Studies conducted for wetlands in other
regions of the U.S. reported habitat and species protection service values that ranged from a low of
$168.96/acre/year to a high of $403.16/acre/year, with a mean and median value of $260.09/acre/year and
$258.14/acre/year, respectively.16, 17 One international study reported an aggregate world-wide wildlife
habitat service value of $142.92/acre/year for coastal wetlands. Considering only coastal zone wetlands
across all study categories, the value of habitat and species protection ranged from $168.96/acre/year to
15
  Other independent variables are also employed, including the theoretically requisite income and various potential
demand shifters, depending on the situation being modeled.
16
  All values in year 2000 dollars.
17
  It should be emphasized that all but one of the reported U.S. valuation studies were conducted by one set of
authors in the mid-1970s. The importance of this information to understanding the value of habitat and species
protection services derived wetlands is not clear, although it is always preferable to have multiple, independent
studies on which to base inferences.



                             6
$403.16/acre/year, with a mean and median of $249.44/acre/year and $253.47/acre/year, respectively.
For comparison purposes, reported estimates of willingness-to-pay (WTP) values for habitat and species
protection ranged from a low of $30.12 to $434.67, with a mean and median of $211.59 and 213.86,
respectively. Geographic location and type of wetland appeared to have a relatively minor impact on the
estimated values.




                          7
Table 1. Published estimates of habitat and species protection service values provided by wetlands, 1975-2001.
                              Site                Discount    Time                                   NPV      Annualized      Annualized
                Site            Size                  Rate  Horizon                          Base      Estimate     Value/Acre      Value/Acre
                                                                                                              (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)   Valuation Method       (%)   (years)                         Year     (base yr $)     (base yr $)

       --------------------------------------------------------------------------------------------- U.S. Specific Studies ---------------------------------------------------------------------------------------------
                                                                                                       36.01b
Gupta and      White Cedar     -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970         670                  168.96
Foster 1975     Bog,                 habitat              price scaled by wildlife
           Massachusetts                             habitat productivity score

                                                                                                       39.99b
Gupta and      Otis Fresh      -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970         744                  187.64
Foster 1975     Meadows,               habitat              price scaled by wildlife
           Massachusetts                             habitat productivity score

                                                                                                       46.39 b
Gupta and      Bear         -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970         893                  217.67
Foster 1975     Meadows,               habitat              price scaled by wildlife
           Massachusetts                             habitat productivity score

                                                                                                       48.97b
Gupta and      Hyannis       -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970         911                  229.77
Foster 1975     Wooded                habitat              price scaled by wildlife
           Swamp,                                 habitat productivity score
           Massachusetts

                                                                                                       54.02 b
Gupta and      Moore's Pond,    -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970        1,005                  253.47
Foster 1975     Massachusetts            habitat              price scaled by wildlife
                                              habitat productivity score

                                                                                                       56.01 b
Gupta and      Chicopee       -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970        1,042                  262.80
Foster 1975     River                habitat              price scaled by wildlife
           Marshes,                                habitat productivity score
           Massachusetts

                                                                                                       58.00 b
Gupta and      Hoosic River     -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970        1,079                  272.14
Foster 1975     Swamp,                habitat              price scaled by wildlife
           Massachusetts                             habitat productivity score

                                                                                                       63.00 b
Gupta and      Lawrence       -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970        1,172                  295.60
Foster 1975     Swamp,                habitat              price scaled by wildlife
           Massachusetts                             habitat productivity score

                                                                                                       66.01 b
Gupta and      Wenham        -----      Wildlife         -----  Average state acquisition          5.375     Infinite    1970        1,228                  309.73
Foster 1975     Swamp,                habitat              price scaled by wildlife
           Massachusetts                             habitat productivity score




                                                            8
Table 1. Published estimates of habitat and species protection service values provided by wetlands, 1975-2001 – continued.
                              Site                Discount    Time                                  NPV      Annualized      Annualized
                Site            Size                  Rate  Horizon Base                              Estimate     Value/Acre      Value/Acre
                                                                                                             (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)   Valuation Method       (%)   (years) Year                            (base yr $)     (base yr $)

      --------------------------------------------------------------------------------------------- U.S. Specific Studies ---------------------------------------------------------------------------------------------
Woodward      -----        Mixed      Wildlife         -----  Econometric meta-analysis of          -----      -----   1990         -----        306        403.16
and Wui 2001                      habitat              39 studies yielding per acre
                                             values; excludes WTP where                                         90% C.I. of
                                             per acre value was not                                            95 - 981
                                             generated


      --------------------------------------------------------------------------------------------- International Studies ---------------------------------------------------------------------------------------------
Costanza et al.  World wide      Coastal     Wildlife         815   Mixed aggregation of various          -----      -----   1994         -----        123        142.92
1997                  wetlands    habitat        million   studies; little detail given
                                             concerning specific studies


      ------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis -------------------------------------------------------------------------
                                                                                                  34.04-73.19 e        30.12 c e
Morrison et al.  New South     Ephem.      Habitat and      297,000   WTP using choice modeling           -----      -----   1997         -----
1999        Wales,       wetlands     endangered                                                                 with job losses
          Australia              species; non-                                                                ($Australian)
                            use
                            employment

                                                                                                  48.75-102.62 e        41.01 c e
Morrison et al.  New South     Ephem.      Habitat and      297,000   WTP using choice modeling           -----      -----   1997         -----
1999        Wales,       wetlands     endangered                                                                  no job losses
          Australia              species; non-                                                                ($Australian)
                            use
                            employment

                                                                                                      51.92 e       72.10 e
Pate and      San Joaquin    General     Protection of      90,000   WTP mail survey of Oregon           -----      -----   1989         -----
Loomis 1997    Valley, CA     wetlands     wildlife from           residents, with emphasis on
                            contamination           distance effect

                                                                                                      88.42 e       105.37 e
Stevens et al.   New        General     rare species        -----  WTP contingent valuation            -----      -----   1993         -----
1995        England      wetlands     protection             mail survey

                                                                                                      86.35 e       119.92 e
Pate and      San Joaquin    General     Protection of      90,000   WTP mail survey of               -----      -----   1989         -----
Loomis 1997    Valley, CA     wetlands     wildlife from           Washington residents, with
                            contamination           emphasis on distance effect

                                                                                                     140.00d e       203.79 e
Creel and     San Joaquin    Wetland     Viewing          -----  Linked site selection and trip         -----      -----   1988         -----
Loomis 1992    Valley,      recreation                     count models
          California     areas
                                                           9
Table 1. Published estimates of habitat and species protection service values provided by wetlands, 1975-2001 – continued.
                               Site               Discount    Time                            NPV       Annualized      Annualized
                Site            Size                  Rate  Horizon Base                        Estimate      Value/Acre      Value/Acre
                                                                                                        (yr 2000 $)a
 Study     Location    Type    Site Use   (acres)    Valuation Method       (%)   (years) Year                       (base yr $)     (base yr $)

       ------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis -------------------------------------------------------------------------
                                                                                                154.00 e       213.86 e
Loomis et al.    San Joaquin    General    Preservation      85,000   WTP contingent valuation          -----     -----   1989        -----
1991        Valley,      wetlands    and                with acreage reference
          California            maintenance

                                                                                                188.00 e       261.08 e
Loomis et al.    San Joaquin    General    Waterbird         -----  WTP contingent valuation          -----     -----   1989        -----
1991        Valley,      wetlands    protection
          California            from
                           increased
                           contamination


                                                                                                203.08 e       282.02 e
Pate and      San Joaquin    General    Protection of     90,000   WTP mail survey of Nevada          -----     -----   1989        -----
Loomis 1997     Valley, CA    wetlands    wildlife from           residents, with emphasis on
                           contamination           distance effect

                                                                                                222.69 e       309.25 e
Pate and      San Joaquin    General    Protection of     90,000   WTP mail survey of             -----     -----   1989        -----
Loomis 1997     Valley, CA    wetlands    wildlife from           California residents outside
                           contamination           the San Joaquin Valley, with
                                            emphasis on distance effect

                                                                                                233.86 e       324.76 e
Pate and      San Joaquin    General    Protection of     90,000   WTP mail survey San             -----     -----   1989        -----
Loomis 1997     Valley, CA    wetlands    wildlife from           Joaquin Valley residents, with
                           contamination           emphasis on distance effect

                                                                                                254.00 e       352.73 e
Loomis et al.    San Joaquin    General    Improvement     125,000   WTP contingent valuation          -----     -----  1989?         -----
1991        Valley,      wetlands                     with acreage reference
          California

                                                                                           313.00 e      434.67 e
Loomis et al.    San Joaquin   General    Decrease      125,000 WTP contingent valuation          -----     ----- 1989?        -----
1991        Valley,     wetlands    contamination
          California           of waterbirds
 a
   Study values inflated to common year 2000 values using the Bureau of Labor Statistics (BLS) CPI Inflation Calculator, which bases yearly adjustments on the average consumer price index by year.
 b
   All values were based on a $70/acre/year value for a site with a score of 100 on the productivity scale.
 c
   Inflated to year 2000 using the BLS CPI Inflation Calculator and converted to U.S. dollars using the ratio $1.89 Australian/$1.00 U.S.
 d
   Mean of two differently specified models.
 e
   Value is not reported on a per acre per year basis. In most cases, the value represents household willingness-to-pay for the service where the service/wetland quantity relationship is not defined.




                                                        10
Table 2. Published estimates of total service values provided by wetlands, 1975-2001.
                               Site                                Discount      Time              NPV      Annualized      Annualized
                 Site            Size                                  Rate     Horizon     Base      Estimate     Value/Acre      Value/Acre
                                                                                                             (yr 2000 $)a
 Study     Location    Type     Site Use   (acres)   Valuation Method                        (%)     (years)    Year     (base yr $)     (base yr $)

      ------------------------------------------------------------------------------------------- Louisiana Specific Studies -------------------------------------------------------------------------------------------
Costanza and    Terrebonne      Coastal     Summation      650,000   Simple summation of mixed           8.0     Infinite   1983       586.73         46.94         81.16
Farber 1987    Parish,       Louisiana    of                method estimates of
          Louisiana              commercial            individual services
                            fishing,
                            trapping,
                            recreation,
                            and storm
                            protection

                                                                                                     194.32b
Costanza et al.  Louisiana      Coastal     Commercial        -----  Production function, revenue       8.0 , 3.0    Infinite   1983    2,429 - 8,977                   335.96
1989                  wetlands    fishing,             accounting, travel cost, and
                            trapping,             WTP contingent valuation
                            recreation,
                            and storm
                            protection

Costanza and    Terrebonne      Fresh      All services     650,000   Energy analysis based gross          8.0     Infinite   1983        6,400       512.00         885.20
Farber 1987,    Parish,       coastal                      primary productivity
Costanza et al.  Louisiana      wetlands                     conversion, net value lost
1989                                           when converting wetland to
                                             open water

Costanza and    Terrebonne      Saltwater    All services     650,000   Energy analysis based gross          8.0     Infinite   1983        6,700       536.00         926.70
Farber 1987    Parish,       coastal                      primary productivity
          Louisiana      wetlands                     conversion, net value lost
                                             when converting wetland to
                                             open water

Costanza and    Terrebonne      Brackish    All services     650,000   Energy analysis based gross          8.0     Infinite   1983       10,602        848.16        1,466.40
Farber 1987    Parish,       coastal                      primary productivity
          Louisiana      wetlands                     conversion, net value lost
                                             when converting wetland to
                                             open water




                                                          11
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                       Time            NPV        Annualized      Annualized
                 Site            Size                 Rate                     Horizon    Base     Estimate       Value/Acre      Value/Acre
                                                                                                            (yr 2000 $)a
 Study     Location    Type     Site Use   (acres)   Valuation Method       (%)                      (years)    Year     (base yr $)      (base yr $)

     --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
van Vuuren    Lake St. Clair,   Freshwate    Public and        741   Travel cost                   4.0       50   1985         4,435        83.55        133.71
and Roy 1993   Michigan &      r wetlands   club hunting,    undiked
         Canada                angling,
                           trapping

Gupta and    Massachusetts    LLNN      Benefits of        -----  Average state acquisition            7.0       30   1972          500          40        165
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)

van Vuuren    Lake St. Clair,   Freshwate    Public and       370.7   Travel cost                   4.0       50   1985         6,027        113.54       181.71
and Roy 1993   Michigan &      r wetlands   club hunting,      diked
         Canada                angling,
                           trapping

van Vuuren    Lake St. Clair,   Freshwate    Public and        49.4   Travel cost                   4.0       50   1985         6,968        131.27       210.08
and Roy 1993   Michigan &      r wetlands   club hunting,      diked
         Canada                angling,
                           trapping

Roberts and   Mud Lake,      Fresh      All services       -----  Cost savings, residual return         -----      -----   1995          -----        375       423.72
Leitch 1997   MN-SD        wetland                      to water utilities, contingent
                                            valuation

Gupta and    Massachusetts    HLNN      Benefits of        -----  Average state acquisition            7.0       30   1972         1,400         113        466
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)

Gupta and    Massachusetts    LLNH      Benefits of        -----  Average state acquisition            7.0       30   1972         1,700         137        564
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)


                                                         12
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                       Time            NPV        Annualized      Annualized
                 Site            Size                 Rate                     Horizon    Base     Estimate       Value/Acre      Value/Acre
                                                                                                            (yr 2000 $)a
 Study     Location    Type     Site Use   (acres)   Valuation Method       (%)                      (years)    Year     (base yr $)      (base yr $)

     --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Gupta and    Massachusetts    MMNM      Benefits of        -----  Average state acquisition            7.0       30   1972         3,000         242        997
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)

Gupta and    Massachusetts    LHNL      Benefits of        -----  Average state acquisition            7.0       30   1972         4,100         330       1,359
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)

Gupta and    Massachusetts    HHNH      Benefits of        -----  Average state acquisition            7.0       30   1972         6,000         484       1,994
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)

Gupta and    Massachusetts    LLLL      Benefits of        -----  Average state acquisition            7.0       30   1972         6,400         519       2,138
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)

Gupta and    Massachusetts    HHLH      Benefits of        -----  Average state acquisition            7.0       30   1972         11,700         943       3,885
Foster 1975              Wetland     wildlife,             price scaled by habitat score
                           visual/cultur           (wildlife) or quality (visual
                           al, water             cultural), 1971 ACE study of
                           supply, and            Charles River (flood control),
                           flood control           1970 USGS study (supply)




                                                         13
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                         Time            NPV        Annualized      Annualized
                 Site            Size                 Rate                        Horizon    Base     Estimate       Value/Acre      Value/Acre
                                                                                                               (yr 2000 $)a
 Study     Location    Type     Site Use   (acres)   Valuation Method       (%)                        (years)    Year     (base yr $)      (base yr $)

       --------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Gupta and       Massachusetts    HHMH      Benefits of        -----  Average state acquisition            7.0       30   1972         26,000         2,095       12,750
Foster 1975                Wetland     wildlife,             price scaled by habitat score
                              visual/cultur           (wildlife) or quality (visual
                              al, water             cultural), 1971 ACE study of
                              supply, and            Charles River (flood control),
                              flood control           1970 USGS study (supply)

Gupta and       Massachusetts    LLHL      Benefits of        -----  Average state acquisition            7.0       30   1972         40,700         3,280       13,512
Foster 1975                Wetland     wildlife,             price scaled by habitat score
                              visual/cultur           (wildlife) or quality (visual
                              al, water             cultural), 1971 ACE study of
                              supply, and            Charles River (flood control),
                              flood control           1970 USGS study (supply)


        --------------------------------------------------------------------------------------------- International Studies ---------------------------------------------------------------------------------------------
Gupta and       Massachusetts    HHHH      Benefits of        -----  Average state acquisition            7.0       30   1972         46,000         3,707       15,271
Foster 1975                Wetland     wildlife,             price scaled by habitat score
                              visual/cultur           (wildlife) or quality (visual
                              al, water             cultural), 1971 ACE study of
                              supply, and            Charles River (flood control),
                              flood control           1970 USGS study (supply)

Thibodeau       Charles River    Costal     All services      8,535   Simple summation of mixed             6    Infinite   1978        171,772      10,306.32        27,220
and Ostro       Basin        wetlands                     method estimates of
1981                                             individual services

                                                                                                                  174.13c
Gren et al.      Danube        Mixed      All           4.3 m   Summation of individual          5.0 and     infinite   1991       3,027 ecu     151.35 ecu
1995         floodplain              ecosystem             service estimates               2.0                         to
                              services                                   percent                     7568 ecu
                                                                                             per acre

Costanza et al.    World wide      Coastal     All services      815 m   Mixed aggregation of various          -----      -----   1994          -----        5,983       6,952
1997                    wetlands    and products      world   studies; little detail given
                                          wide   concerning specific studies




                                                            14
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                         Time            NPV        Annualized      Annualized
                 Site            Size                 Rate                       Horizon    Base     Estimate       Value/Acre      Value/Acre
                                                                                                              (yr 2000 $)a
 Study     Location    Type     Site Use   (acres)   Valuation Method       (%)                        (years)    Year     (base yr $)      (base yr $)

       --------------------------------------------------------------------------------------------- International Studies ---------------------------------------------------------------------------------------------
                                                                                                        1,553d
Sathirathai     Thailand       Mangrove    Direct and     988      various                    -----      -----   1993          -----                 1,851
and Barbier                wetland     indirect use
2001                           (timber,
                             fishing,
                             coastline
                             protection)


     ---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
                                                                                                        20.77 e       23.47 e
Mullarkey and    Northwest      Fresh      Total value        110   WTP mail survey; respondent          -----      -----   1995          -----
Bishop 1999     Wisconsin      wetland     under high            certainty and scope test
                             certainty             included

                                                                                                        57.83 e       65.34 e
Mullarkey and    Northwest      Fresh      Total value        110   WTP mail survey; respondent          -----      -----   1995          -----
Bishop 1999     Wisconsin      wetland     under low             certainty and scope test
                             certainty             included

                                                                                                        67.80 e       94.15 e
Pate and       San Joaquin     General     Generalized      90,000   WTP mail survey of Oregon           -----      -----   1989          -----
Loomis 1997     Valley, CA      wetlands    to all uses            residents

                                                                                                         252 e      100.79 e
Loomis et al.    Nebraska       Platte     Wastewater      300,000   WTP mail survey                -----      -----   1998          -----
2000                   River      dilution,
                             water
                             purification,
                             erosion
                             control,
                             habitat, and
                             recreation

                                                                                                       114.29 e      136.20 e
Stevens et al.    New England     General     Recreation,        -----  WTP contingent valuation            -----      -----   1993          -----
1995                   wetlands    rare species,           mail survey
                             food
                             production,
                             flood
                             protection,
                             water supply
                             and pollution
                             control



                                                           15
Table 2. Published estimates of total service values provided by wetlands, 1975-2001 -- continued.
                               Site               Discount                    Time            NPV        Annualized     Annualized
                 Site            Size                 Rate                   Horizon    Base     Estimate      Value/Acre     Value/Acre
                                                                                                        (yr 2000 $)a
 Study     Location    Type     Site Use   (acres)   Valuation Method       (%)                   (years)    Year    (base yr $)      (base yr $)

     ---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
                                                                                                  99.75 e       138.52 e
Pate and      San Joaquin    General     Generalized     90,000   WTP mail survey of             -----     -----   1989         -----
Loomis 1997     Valley, CA     wetlands    to all uses           Washington residents

                                                                                                 196.01 e       272.20 e
Pate and      San Joaquin    General     Generalized     90,000   WTP mail survey of Nevada          -----     -----   1989         -----
Loomis 1997     Valley, CA     wetlands    to all uses           residents

                                                                                                 210.77 e       292.70 e
Pate and      San Joaquin    General     Generalized     90,000   WTP mail survey California         -----     -----   1989         -----
Loomis 1997     Valley, CA     wetlands    to all uses           residents outside the San
                                            Joaquin Valley

                                                                                                 215.55 e       299.34 e
Pate and      San Joaquin    General     Generalized     90,000   WTP mail survey of San           -----     -----   1989         -----
Loomis 1997     Valley, CA     wetlands    to all uses           Joaquin Valley residents
 a
   Study values inflated to common year 2000 values using the Bureau of Labor Statistics (BLS) CPI Inflation Calculator, which bases yearly adjustments on the average consumer price index by year.
 b
   Storm protection accounted for 79 percent ($153.20/acre/yr) of the total value.
 c
   Inflated to year 2000 using the BLS CPI Inflation Calculator and converted to U.S. dollars using the ratio 1.10 ecu/$1.00 U.S.
 d
   Value is strongly influenced by estimates for coastline protection, which account for 96% of the total.
 e
   Value is not reported on a per acre per year basis. In most cases, the value represents household willingness-to-pay for the service where the service/wetland quantity relationship is not defined.




                                                        16
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by Chris Kennedy last modified 26-01-2007 12:50
 

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