Fishing and resource review
Economic Linkages Between Coastal Wetlands and Hunting and Fishing:
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 2001-03
LSU Agricultural Economics & Agribusiness May 2001
Economic Linkages Between Coastal Wetlands and Hunting and Fishing:
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 12 peer-reviewed studies,1 published from 1978 to 2001,
reporting 32 separate estimates for the disaggregate2 value of hunting and fishing services provided by
coastal and non-coastal wetlands. Estimates ranged across three orders of magnitude and are highly
dependent on the specific geographic site providing the service, the target species of the hunting and
fishing activity, and the measurement technique. Considering only coastal zone wetlands across all study
categories, the value of wetlands to single-target hunting and fishing (oysters, menhaden, etc.) ranged
from $1.05/acre/year to $663.74/acre/year, with a mean and median of $113.95/acre/year and
$10.03/acre/year, respectively. Considering only coastal zone wetlands across all study categories, the
value of wetlands to aggregate hunting or fishing (both commercial and recreational) ranged from
$16.76/acre/year to $1,025.03/acre/year, with a mean and median of $233.37/acre/year and
$106.54/acre/year, respectively. 3, 4 By comparison, the range of reported estimates of willingness-to-pay
(WTP) values for recreational hunting and fishing services were somewhat more narrowly bounded
across studies,5 ranging $83.99 to $616.46, with a mean and median of $303.67 and $207.79,
respectively. The importance of a wetlands geographic location, its relationship to the target fishery or
animals species, and the differing relationships with commercial and recreational consumptive users
suggests that coastal wetland benefits need to be carefully examined within a spatially disaggregated
context.
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
1
To the author’s knowledge this represents all the peer-reviewed published studies that explicitly seek to value the
linkage between wetlands and disaggregate hunting and fishing services, both commercial and recreational.
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 hunting and fishing services
may, in many cases, simultaneously provide for increased habitat and species protection. Valuing each of these
services separately (when, in fact, they may be 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 hunting
and fishing, 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.
5
Note that the WTP estimates were not, in general, estimated on a per acre basis, and thus should not be directly
compared with the per acre values estimated from non-WTP studies.
1
deemphasized 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 important, but only partially marketed, service provided by Louisiana's coastal wetlands is
ecological support for species that are the target of commercial and recreational hunting and fishing.
Dockside revenues for commercial fisheries in Louisiana were $317 million in 1997, which were second
only to Alaska.6 The most important commercial species included shrimp ($144 million), menhaden ($63
million), blue crab ($28 million), and oyster ($30 million). In addition, inshore and offshore fish stocks
support a large recreational sector. In 1996, this sector harvested an estimated 23.4 million pounds of fish
during the 3.14 million trips taken by 607,000 participants. Estimated recreational expenditures totaled
$450 million in 1996, surpassing the value of the commercial fishery. Problems, however, lie in the fact
that little information exists about the relationship between functioning coastal wetland ecosystems and
the related hunting and fishing resources.
This report documents the current status of knowledge concerning the economic value of the
commercial and recreational hunting and fishing services generated by coastal and other wetlands. In
particular, studies that focus on valuing hunting and fishing services as unbundled products of wetland
function are highlighted.7 A brief overview of the economic linkages between wetland ecosystems and
hunting and fishing 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 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 hunting and
fishing service valuation studies are presented and summarized. Lastly, the report concludes with a
complete list of the literature cited.
Relationship Between Wetlands and Hunting and Fishing
Policymakers face complex, multi-objective trade-offs when attempting to develop strategies for
coastal restoration and protection.8 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 hunting and fishing resources is the heterogeneity of existing wetlands.
6
The statistics reported in this paragraph come from Keithly and Ward (2001).
7
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 hunting and fishing value estimates.
8
The following discussion was adapted from Keithly and Ward (2001) and Heimlich et al. (1998).
2
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, both commercial and recreational hunting and fishing 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 number of empirical studies that isolate the hunting and fishing 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.9 The provision of hunting and fishing resources 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.10 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 fur-bearing
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 biophysical functions with economic value comes from the net market and nonmarket value of the
species. Market values are calculated by observing prices and relating them to estimates of production
and harvesting costs, thereby allowing a relatively clear determination of the net economic value of the
harvest attributable to wetlands. Linkages that are less clear are those involving nonmarket valuation,
where estimating the relationship between habitat and nonconsumptive uses is extremely complicated
because of biological, recreational, sociological, and economic considerations that interact in complex
ways. In addition, wetlands policy is complicated by the fact that many wetland goods and services are
public goods whose benefits accrue to society at large or to individuals other than the wetland owners. For
example, a wetland may provide habitat for migratory birds that are targets of hunting, but fail to generate
significant rent for its owner. 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
9
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.
10
And thus the joint-product link between hunting and fishing resources and the water quality services of wetlands.
3
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.
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.11
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.12
Four theoretically plausible valuation methods have been used in the neoclassical economic
literature to place valid dollar values on wetland resources.13 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.14 Shabman and Batie (1978)
detailed the fundamental problems and economic fallacies imbedded in this approach,15 and no further
11
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).
12
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.
13
The brief methods discussion borrows from Amacher et al. (1989), Whitehead (1992), and others.
14
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).
15
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,
4
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
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.16 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
these inaccurate estimates may capture the focus of policy debate, and hinder, rather than improve, the resource
management process for coastal wetlands."
16
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
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
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.17 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 hunting and fishing service valuation study
depends primarily on the ability to quantitatively discern the biophysical linkages between characteristics
of a particular wetland area and the change in the quality and quantity of hunting and fishing resources.
In cases where this relationship is well understood, NFI methods can be employed. In cases where the
biophysical linkages are not well described, but the demanded hunting and fishing services can be
defined, then RCM or CVM may be most appropriate even in light of their limitations. Given its nature,
recreational hunting and fishing service values are often estimated using TCM approaches. No hunting
and fishing service value studies were found that employed HPM approaches. Of course, the choice of a
particular measurement method is important and can have implications for the estimated value of a
wetland area. For example, in a meta-analysis of wetlands valuation studies, Woodward and Wui (2000)
discovered that NFI methods tended to generate lower estimated values for wetlands than did RCM. This
confirms the Anderson and Rockel (1991) observation that RCM should generate an upper bound on
actual value.
17
Other independent variables are also employed, including the theoretically requisite income and various potential
demand shifters, depending on the situation being modeled.
6
Review of Estimated Values
Peer-reviewed literature estimates of the hunting and fishing service values generated by an acre
of wetland are presented in Table 1. Four different categories of studies were identified; Louisiana
specific studies, other U.S. studies, international studies, and studies that did not report their results on an
area basis (primarily CVM based WTP studies). In addition, peer-reviewed literature estimates of total
service values generated by an acre of wetland were arranged by the same four categories and are
presented in Table 2. The overall service value estimates are potentially useful when evaluating a study,
as individually disaggregated service values should (obviously) never exceed total service value. In fact,
individually disaggregated service values, when summed across all service categories, also should not
exceed total value. In any event, the total values are included in the report to help the reader gain a
broader understanding of the information available in the valuation literature.
Reported estimates for the value of Louisiana wetlands in the provision of specific hunting and
fishing services ranged from a low of $1.16/acre/year (blue crab) to a high of $18.78/acre/year (shrimp),
with a mean and median value of $10.97/acre/year and $11.97/acre/year, respectively (Table 1).18 The
disparity in valuation can be linked primarily to differences in the markets for specific target species
being investigated. The two existing studies that examined the role of Louisiana wetlands in aggregate
commercial resource production estimated values of $20.90/acre/year for trapping and $43.85/acre/year
for fishing. Given these aggregated service values, the values reported for individual target species
appear plausible (and visa versa). 19
Studies conducted for wetlands in other regions of the U.S. reported specific hunting and fishing
service values that ranged from $1.05/acre/year (blue crab in Florida) to $663.74/acre/year (oyster at
Northumberland, Virginia), with a mean and median value of $152.28/acre/year and $8.73/acre/year,
respectively (Table 1). While some of the individual estimates fell within the range of values reported for
Louisiana, a number of them were substantially higher. In particular, wetland valuation through
ecological support of Chesapeake Bay oyster production was generally one order of magnitude higher
than the value estimated for Louisiana wetlands, although the Virginia values ranged across two orders of
magnitude. A meta-analysis of the role of wetlands in commercial fishing estimated its value at
$1,025.03/acre/year. The value of wetlands in the U.S. recreational hunting and fishing industry fell
between these extremes, ranging from a low of $8.63/acre/year (muskrat trapping) to $871.39/acre/year
for estuarine-dependent fish species, with a mean and median value of $204.02/acre/year and
$112.17/acre/year, respectively.
A limited number of international studies reported commercial and recreational hunting and
fishing service values between $16.76/acre/year and $120.84/acre/year, with a mean and median value of
$54.21/acre/year and $25.03/acre/year, respectively. Considering only coastal zone wetlands across all
study categories, the value of wetlands to single-target hunting and fishing (oysters, menhaden, etc.)
ranged from $1.05/acre/year to $663.74/acre/year, with a mean and median of $113.95/acre/year and
$10.03/acre/year, respectively. Considering only coastal zone wetlands across all study categories, the
value of wetlands to aggregate hunting or fishing (both commercial and recreational) ranged from
$16.76/acre/year to $1,025.03/acre/year, with a mean and median of $233.37/acre/year and
$106.54/acre/year, respectively.
18
All values in year 2000 dollars.
19
It should be emphasized that all of the reported Louisiana valuation studies were conducted by one set of authors
in a very specific time period. The importance of this information to understanding the value of water quality
services derived from Louisiana wetlands is not clear, although it is always preferable to have multiple, independent
studies on which to base inferences.
7
For comparison purposes, reported estimates of willingness-to-pay (WTP) values for wetland
hunting and fishing services ranged from a low of $83.99 to $616.46, with a mean and median of $303.67
and $207.79, respectively (Table 1). Variability among the WTP estimates was essentially similar to
those generated by the other valuation methods, and they yielded similar valuation levels.
8
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001.
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 Commercial ----- Secondarily calculated ----- ----- 1983 ----- 0.67 1.16
Farber 1987 Parish, Louisiana blue crab marginal value product
Louisiana fishery
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 5.80 10.03
Farber 1987 Parish, Louisiana menhaden marginal value product
Louisiana fishery
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 8.04 13.90
Farber 1987 Parish, Louisiana oyster fishery marginal value product
Louisiana
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 10.86 18.78
Farber 1987 Parish, Louisiana shrimp fishery marginal value product
Louisiana
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 12.09 20.90
Farber 1987, Parish, Louisiana trapping marginal value product
Costanza et al. Louisiana
1989
Costanza et al. Louisiana Coastal Commercial ----- Production function, 8.0 , 3.0 Infinite 1983 317, 846 25.36 43.85
1989 wetlands fishing, marginal value product
--------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Lynne et al. Florida Gulf Coastal Commercial ----- Estimated production 10.0 Infinite 1974 3 0.30 1.05
1981 Coast wetlands blue crab function, marginal value
fishing product
Batie and Accomack, Coastal Oyster ----- Estimated production 10.0 Infinite 1969 11 1.13 5.30
Wilson 1978 Virginia wetlands production function, marginal value
product
Batie and James City, Coastal Oyster ----- Estimated production 10.0 Infinite 1969 16 1.64 7.70
Wilson 1978 Virginia wetlands production function, marginal value
product
9
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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, Freshwater Trapping 49.4 Travel cost 4.0 50 1985 286 5.39 8.63
and Roy 1993 Michigan & wetlands diked
Canada
Batie and York, Virginia Coastal Oyster ----- Estimated production 10.0 Infinite 1969 19 1.88 8.82
Wilson 1978 wetlands production function, marginal value
product
van Vuuren Lake St. Clair, Freshwater Public hunting 49.4 Travel cost 4.0 50 1985 567 10.68 17.09
and Roy 1993 Michigan & wetlands diked
Canada
Batie and Virginia Coastal Oyster ----- Estimated production 10.0 Infinite 1969 42 4.24 19.89
Wilson 1978 Beach, wetlands production function, marginal value
Virginia product
van Vuuren Lake St. Clair, Freshwater Public hunting 741 Travel cost 4.0 50 1985 1,094 20.61 32.98
and Roy 1993 Michigan & wetlands undiked
Canada
van Vuuren Lake St. Clair, Freshwater Angling 741 Travel cost 4.0 50 1985 2,488 46.87 75.01
and Roy 1993 Michigan & wetlands undiked
Canada
Woodward ----- Mixed Bird hunting ----- Econometric meta-analysis ----- ----- 1990 ----- 70 92.23
and Wui 2001 of 39 studies yielding per
acre values; excludes WTP 90% C.I. of
where per acre value was 25 - 197
not generated
981b
Bell 1997 Florida west Estuarine Recreational ----- Estimated production 8.125 Infinite 1984 79.71 132.11
coast saltwater fishing for function linked with angler
marsh estuarine demand function to
dependent calculate consumer surplus
species
10
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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, Freshwater Hunting clubs 370.7 Travel cost 4.0 50 1985 5,174 97.47 155.99
and Roy 1993 Michigan & wetlands diked
Canada
van Vuuren Lake St. Clair, Freshwater Hunting clubs 49.4 Travel cost 4.0 50 1985 6,115 115.20 184.36
and Roy 1993 Michigan & wetlands diked
Canada
Woodward ----- Mixed Recreational ----- Econometric meta-analysis ----- ----- 1990 ----- 357 470.36
and Wui 2001 fishing of 39 studies yielding per
acre values; excludes WTP 90% C.I. of
where per acre value was 95 - 1,342
not generated
Batie and Westmoreland Coastal Oyster ----- Estimated production 10.0 Infinite 1969 1,072 107.22 503.09
Wilson 1978 Virginia wetlands production function, marginal value
product
Batie and Northumber- Coastal Oyster ----- Estimated production 10.0 Infinite 1969 1,414 141.46 663.74
Wilson 1978 land, Virginia wetlands production function, marginal value
product
6,471b
Bell 1997 Florida east Estuarine Recreational ----- Estimated production 8.125 Infinite 1984 525.77 871.39
coast saltwater fishing for function linked with angler
marsh estuarine demand function to
dependent calculate consumer surplus
species
Woodward ----- Mixed Commercial ----- Econometric meta-analysis ----- ----- 1990 ----- 778 1,025.03
and Wui 2001 fishing of 39 studies yielding per
acre values; excludes WTP 90% C.I. of
where per acre value was 108 - 5,618
not generated
11
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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 ---------------------------------------------------------------------------------------------
16.76c
Kosz et al. Vienna Danube Recreational ----- Prices paid for permits ----- ----- 1991 14.57 ecu
1992 National Park floodplain hunting
contained
in Park
21d
Sathirathai Thailand Mangrove Offshore 988 Production function ----- ----- 1993 n.a 25.03
and Barbier wetland fishery, all
2001 species
Costanza et al. World wide Coastal Food 815 m Mixed aggregation of ----- ----- 1994 ----- 104 120.84
1997 wetlands production world various studies; little detail
wide given concerning specific
studies
---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
55.41e g 83.99g
Cooper and San Joaquin Seven Recreational ----- Travel cost model ----- ----- 1987 -----
Loomis 1991 Valley, freshwater waterfowl
California wildlife hunting
reserves
103-323 g 170.71-535.33 g
Farber 1988 Terrebonne Coastal Recreational 650,000 Travel cost model, direct ----- ----- 1984 -----
Parish hunting and WTP, demand function per
wetlands fishing derived consumer surplus household,
combined depending on
method and
assumptions
131.50 f g 191.41 g
Creel and San Joaquin Freshwater Recreational ----- Linked site selection and ----- ----- 1988 -----
Loomis 1992 Valley, recreational fishing only trip count models
California areas
154.00 f g 224.17 g
Creel and San Joaquin Freshwater Recreational ----- Linked site selection and ----- ----- 1988 -----
Loomis 1992 Valley, recreational hunting only trip count models
California areas
12
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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 ----------------------------------------------------------------------------
423.50 f g 616.46 g
Creel and San Joaquin Freshwater Recreational ----- Linked site selection and ----- ----- 1988 -----
Loomis 1992 Valley, recreational hunting and trip count models
California areas fishing
combined
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
East-west difference due to different WTP estimates and marsh abundance levels.
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
Under the assumption of a unitary demand elasticity.
e
Consumer surplus per hunter day.
f
Mean of two differently specified models.
g
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.
13
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
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 $)
--------------------------------------------------------------------------------------------- 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)
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 $)
--------------------------------------------------------------------------------------------- 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)
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)
16
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 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
1,553d
Sathirathai Thailand Mangrove Direct and 988 various ----- ----- 1993 ----- 1,851
and Barbier wetland indirect use
2001 (timber,
fishing,
coastline
protection)
17
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 ----------------------------------------------------------------------------
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
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
18
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 ----------------------------------------------------------------------------
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.
19
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22
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 2001-03
LSU Agricultural Economics & Agribusiness May 2001
Economic Linkages Between Coastal Wetlands and Hunting and Fishing:
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 12 peer-reviewed studies,1 published from 1978 to 2001,
reporting 32 separate estimates for the disaggregate2 value of hunting and fishing services provided by
coastal and non-coastal wetlands. Estimates ranged across three orders of magnitude and are highly
dependent on the specific geographic site providing the service, the target species of the hunting and
fishing activity, and the measurement technique. Considering only coastal zone wetlands across all study
categories, the value of wetlands to single-target hunting and fishing (oysters, menhaden, etc.) ranged
from $1.05/acre/year to $663.74/acre/year, with a mean and median of $113.95/acre/year and
$10.03/acre/year, respectively. Considering only coastal zone wetlands across all study categories, the
value of wetlands to aggregate hunting or fishing (both commercial and recreational) ranged from
$16.76/acre/year to $1,025.03/acre/year, with a mean and median of $233.37/acre/year and
$106.54/acre/year, respectively. 3, 4 By comparison, the range of reported estimates of willingness-to-pay
(WTP) values for recreational hunting and fishing services were somewhat more narrowly bounded
across studies,5 ranging $83.99 to $616.46, with a mean and median of $303.67 and $207.79,
respectively. The importance of a wetlands geographic location, its relationship to the target fishery or
animals species, and the differing relationships with commercial and recreational consumptive users
suggests that coastal wetland benefits need to be carefully examined within a spatially disaggregated
context.
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
1
To the author’s knowledge this represents all the peer-reviewed published studies that explicitly seek to value the
linkage between wetlands and disaggregate hunting and fishing services, both commercial and recreational.
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 hunting and fishing services
may, in many cases, simultaneously provide for increased habitat and species protection. Valuing each of these
services separately (when, in fact, they may be 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 hunting
and fishing, 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.
5
Note that the WTP estimates were not, in general, estimated on a per acre basis, and thus should not be directly
compared with the per acre values estimated from non-WTP studies.
1
deemphasized 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 important, but only partially marketed, service provided by Louisiana's coastal wetlands is
ecological support for species that are the target of commercial and recreational hunting and fishing.
Dockside revenues for commercial fisheries in Louisiana were $317 million in 1997, which were second
only to Alaska.6 The most important commercial species included shrimp ($144 million), menhaden ($63
million), blue crab ($28 million), and oyster ($30 million). In addition, inshore and offshore fish stocks
support a large recreational sector. In 1996, this sector harvested an estimated 23.4 million pounds of fish
during the 3.14 million trips taken by 607,000 participants. Estimated recreational expenditures totaled
$450 million in 1996, surpassing the value of the commercial fishery. Problems, however, lie in the fact
that little information exists about the relationship between functioning coastal wetland ecosystems and
the related hunting and fishing resources.
This report documents the current status of knowledge concerning the economic value of the
commercial and recreational hunting and fishing services generated by coastal and other wetlands. In
particular, studies that focus on valuing hunting and fishing services as unbundled products of wetland
function are highlighted.7 A brief overview of the economic linkages between wetland ecosystems and
hunting and fishing 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 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 hunting and
fishing service valuation studies are presented and summarized. Lastly, the report concludes with a
complete list of the literature cited.
Relationship Between Wetlands and Hunting and Fishing
Policymakers face complex, multi-objective trade-offs when attempting to develop strategies for
coastal restoration and protection.8 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 hunting and fishing resources is the heterogeneity of existing wetlands.
6
The statistics reported in this paragraph come from Keithly and Ward (2001).
7
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 hunting and fishing value estimates.
8
The following discussion was adapted from Keithly and Ward (2001) and Heimlich et al. (1998).
2
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, both commercial and recreational hunting and fishing 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 number of empirical studies that isolate the hunting and fishing 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.9 The provision of hunting and fishing resources 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.10 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 fur-bearing
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 biophysical functions with economic value comes from the net market and nonmarket value of the
species. Market values are calculated by observing prices and relating them to estimates of production
and harvesting costs, thereby allowing a relatively clear determination of the net economic value of the
harvest attributable to wetlands. Linkages that are less clear are those involving nonmarket valuation,
where estimating the relationship between habitat and nonconsumptive uses is extremely complicated
because of biological, recreational, sociological, and economic considerations that interact in complex
ways. In addition, wetlands policy is complicated by the fact that many wetland goods and services are
public goods whose benefits accrue to society at large or to individuals other than the wetland owners. For
example, a wetland may provide habitat for migratory birds that are targets of hunting, but fail to generate
significant rent for its owner. 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
9
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.
10
And thus the joint-product link between hunting and fishing resources and the water quality services of wetlands.
3
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.
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.11
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.12
Four theoretically plausible valuation methods have been used in the neoclassical economic
literature to place valid dollar values on wetland resources.13 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.14 Shabman and Batie (1978)
detailed the fundamental problems and economic fallacies imbedded in this approach,15 and no further
11
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).
12
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.
13
The brief methods discussion borrows from Amacher et al. (1989), Whitehead (1992), and others.
14
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).
15
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,
4
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
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.16 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
these inaccurate estimates may capture the focus of policy debate, and hinder, rather than improve, the resource
management process for coastal wetlands."
16
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
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
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.17 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 hunting and fishing service valuation study
depends primarily on the ability to quantitatively discern the biophysical linkages between characteristics
of a particular wetland area and the change in the quality and quantity of hunting and fishing resources.
In cases where this relationship is well understood, NFI methods can be employed. In cases where the
biophysical linkages are not well described, but the demanded hunting and fishing services can be
defined, then RCM or CVM may be most appropriate even in light of their limitations. Given its nature,
recreational hunting and fishing service values are often estimated using TCM approaches. No hunting
and fishing service value studies were found that employed HPM approaches. Of course, the choice of a
particular measurement method is important and can have implications for the estimated value of a
wetland area. For example, in a meta-analysis of wetlands valuation studies, Woodward and Wui (2000)
discovered that NFI methods tended to generate lower estimated values for wetlands than did RCM. This
confirms the Anderson and Rockel (1991) observation that RCM should generate an upper bound on
actual value.
17
Other independent variables are also employed, including the theoretically requisite income and various potential
demand shifters, depending on the situation being modeled.
6
Review of Estimated Values
Peer-reviewed literature estimates of the hunting and fishing service values generated by an acre
of wetland are presented in Table 1. Four different categories of studies were identified; Louisiana
specific studies, other U.S. studies, international studies, and studies that did not report their results on an
area basis (primarily CVM based WTP studies). In addition, peer-reviewed literature estimates of total
service values generated by an acre of wetland were arranged by the same four categories and are
presented in Table 2. The overall service value estimates are potentially useful when evaluating a study,
as individually disaggregated service values should (obviously) never exceed total service value. In fact,
individually disaggregated service values, when summed across all service categories, also should not
exceed total value. In any event, the total values are included in the report to help the reader gain a
broader understanding of the information available in the valuation literature.
Reported estimates for the value of Louisiana wetlands in the provision of specific hunting and
fishing services ranged from a low of $1.16/acre/year (blue crab) to a high of $18.78/acre/year (shrimp),
with a mean and median value of $10.97/acre/year and $11.97/acre/year, respectively (Table 1).18 The
disparity in valuation can be linked primarily to differences in the markets for specific target species
being investigated. The two existing studies that examined the role of Louisiana wetlands in aggregate
commercial resource production estimated values of $20.90/acre/year for trapping and $43.85/acre/year
for fishing. Given these aggregated service values, the values reported for individual target species
appear plausible (and visa versa). 19
Studies conducted for wetlands in other regions of the U.S. reported specific hunting and fishing
service values that ranged from $1.05/acre/year (blue crab in Florida) to $663.74/acre/year (oyster at
Northumberland, Virginia), with a mean and median value of $152.28/acre/year and $8.73/acre/year,
respectively (Table 1). While some of the individual estimates fell within the range of values reported for
Louisiana, a number of them were substantially higher. In particular, wetland valuation through
ecological support of Chesapeake Bay oyster production was generally one order of magnitude higher
than the value estimated for Louisiana wetlands, although the Virginia values ranged across two orders of
magnitude. A meta-analysis of the role of wetlands in commercial fishing estimated its value at
$1,025.03/acre/year. The value of wetlands in the U.S. recreational hunting and fishing industry fell
between these extremes, ranging from a low of $8.63/acre/year (muskrat trapping) to $871.39/acre/year
for estuarine-dependent fish species, with a mean and median value of $204.02/acre/year and
$112.17/acre/year, respectively.
A limited number of international studies reported commercial and recreational hunting and
fishing service values between $16.76/acre/year and $120.84/acre/year, with a mean and median value of
$54.21/acre/year and $25.03/acre/year, respectively. Considering only coastal zone wetlands across all
study categories, the value of wetlands to single-target hunting and fishing (oysters, menhaden, etc.)
ranged from $1.05/acre/year to $663.74/acre/year, with a mean and median of $113.95/acre/year and
$10.03/acre/year, respectively. Considering only coastal zone wetlands across all study categories, the
value of wetlands to aggregate hunting or fishing (both commercial and recreational) ranged from
$16.76/acre/year to $1,025.03/acre/year, with a mean and median of $233.37/acre/year and
$106.54/acre/year, respectively.
18
All values in year 2000 dollars.
19
It should be emphasized that all of the reported Louisiana valuation studies were conducted by one set of authors
in a very specific time period. The importance of this information to understanding the value of water quality
services derived from Louisiana wetlands is not clear, although it is always preferable to have multiple, independent
studies on which to base inferences.
7
For comparison purposes, reported estimates of willingness-to-pay (WTP) values for wetland
hunting and fishing services ranged from a low of $83.99 to $616.46, with a mean and median of $303.67
and $207.79, respectively (Table 1). Variability among the WTP estimates was essentially similar to
those generated by the other valuation methods, and they yielded similar valuation levels.
8
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001.
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 Commercial ----- Secondarily calculated ----- ----- 1983 ----- 0.67 1.16
Farber 1987 Parish, Louisiana blue crab marginal value product
Louisiana fishery
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 5.80 10.03
Farber 1987 Parish, Louisiana menhaden marginal value product
Louisiana fishery
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 8.04 13.90
Farber 1987 Parish, Louisiana oyster fishery marginal value product
Louisiana
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 10.86 18.78
Farber 1987 Parish, Louisiana shrimp fishery marginal value product
Louisiana
Costanza and Terrebonne Coastal Commercial ----- Secondarily calculated ----- ----- 1983 ----- 12.09 20.90
Farber 1987, Parish, Louisiana trapping marginal value product
Costanza et al. Louisiana
1989
Costanza et al. Louisiana Coastal Commercial ----- Production function, 8.0 , 3.0 Infinite 1983 317, 846 25.36 43.85
1989 wetlands fishing, marginal value product
--------------------------------------------------------------------------------------------- Additional U.S. Studies ---------------------------------------------------------------------------------------------
Lynne et al. Florida Gulf Coastal Commercial ----- Estimated production 10.0 Infinite 1974 3 0.30 1.05
1981 Coast wetlands blue crab function, marginal value
fishing product
Batie and Accomack, Coastal Oyster ----- Estimated production 10.0 Infinite 1969 11 1.13 5.30
Wilson 1978 Virginia wetlands production function, marginal value
product
Batie and James City, Coastal Oyster ----- Estimated production 10.0 Infinite 1969 16 1.64 7.70
Wilson 1978 Virginia wetlands production function, marginal value
product
9
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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, Freshwater Trapping 49.4 Travel cost 4.0 50 1985 286 5.39 8.63
and Roy 1993 Michigan & wetlands diked
Canada
Batie and York, Virginia Coastal Oyster ----- Estimated production 10.0 Infinite 1969 19 1.88 8.82
Wilson 1978 wetlands production function, marginal value
product
van Vuuren Lake St. Clair, Freshwater Public hunting 49.4 Travel cost 4.0 50 1985 567 10.68 17.09
and Roy 1993 Michigan & wetlands diked
Canada
Batie and Virginia Coastal Oyster ----- Estimated production 10.0 Infinite 1969 42 4.24 19.89
Wilson 1978 Beach, wetlands production function, marginal value
Virginia product
van Vuuren Lake St. Clair, Freshwater Public hunting 741 Travel cost 4.0 50 1985 1,094 20.61 32.98
and Roy 1993 Michigan & wetlands undiked
Canada
van Vuuren Lake St. Clair, Freshwater Angling 741 Travel cost 4.0 50 1985 2,488 46.87 75.01
and Roy 1993 Michigan & wetlands undiked
Canada
Woodward ----- Mixed Bird hunting ----- Econometric meta-analysis ----- ----- 1990 ----- 70 92.23
and Wui 2001 of 39 studies yielding per
acre values; excludes WTP 90% C.I. of
where per acre value was 25 - 197
not generated
981b
Bell 1997 Florida west Estuarine Recreational ----- Estimated production 8.125 Infinite 1984 79.71 132.11
coast saltwater fishing for function linked with angler
marsh estuarine demand function to
dependent calculate consumer surplus
species
10
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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, Freshwater Hunting clubs 370.7 Travel cost 4.0 50 1985 5,174 97.47 155.99
and Roy 1993 Michigan & wetlands diked
Canada
van Vuuren Lake St. Clair, Freshwater Hunting clubs 49.4 Travel cost 4.0 50 1985 6,115 115.20 184.36
and Roy 1993 Michigan & wetlands diked
Canada
Woodward ----- Mixed Recreational ----- Econometric meta-analysis ----- ----- 1990 ----- 357 470.36
and Wui 2001 fishing of 39 studies yielding per
acre values; excludes WTP 90% C.I. of
where per acre value was 95 - 1,342
not generated
Batie and Westmoreland Coastal Oyster ----- Estimated production 10.0 Infinite 1969 1,072 107.22 503.09
Wilson 1978 Virginia wetlands production function, marginal value
product
Batie and Northumber- Coastal Oyster ----- Estimated production 10.0 Infinite 1969 1,414 141.46 663.74
Wilson 1978 land, Virginia wetlands production function, marginal value
product
6,471b
Bell 1997 Florida east Estuarine Recreational ----- Estimated production 8.125 Infinite 1984 525.77 871.39
coast saltwater fishing for function linked with angler
marsh estuarine demand function to
dependent calculate consumer surplus
species
Woodward ----- Mixed Commercial ----- Econometric meta-analysis ----- ----- 1990 ----- 778 1,025.03
and Wui 2001 fishing of 39 studies yielding per
acre values; excludes WTP 90% C.I. of
where per acre value was 108 - 5,618
not generated
11
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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 ---------------------------------------------------------------------------------------------
16.76c
Kosz et al. Vienna Danube Recreational ----- Prices paid for permits ----- ----- 1991 14.57 ecu
1992 National Park floodplain hunting
contained
in Park
21d
Sathirathai Thailand Mangrove Offshore 988 Production function ----- ----- 1993 n.a 25.03
and Barbier wetland fishery, all
2001 species
Costanza et al. World wide Coastal Food 815 m Mixed aggregation of ----- ----- 1994 ----- 104 120.84
1997 wetlands production world various studies; little detail
wide given concerning specific
studies
---------------------------------------------------------------------------- Studies Where Value Not Reported on an Area Basis ----------------------------------------------------------------------------
55.41e g 83.99g
Cooper and San Joaquin Seven Recreational ----- Travel cost model ----- ----- 1987 -----
Loomis 1991 Valley, freshwater waterfowl
California wildlife hunting
reserves
103-323 g 170.71-535.33 g
Farber 1988 Terrebonne Coastal Recreational 650,000 Travel cost model, direct ----- ----- 1984 -----
Parish hunting and WTP, demand function per
wetlands fishing derived consumer surplus household,
combined depending on
method and
assumptions
131.50 f g 191.41 g
Creel and San Joaquin Freshwater Recreational ----- Linked site selection and ----- ----- 1988 -----
Loomis 1992 Valley, recreational fishing only trip count models
California areas
154.00 f g 224.17 g
Creel and San Joaquin Freshwater Recreational ----- Linked site selection and ----- ----- 1988 -----
Loomis 1992 Valley, recreational hunting only trip count models
California areas
12
Table 1. Published estimates of hunting and fishing service values provided by wetlands, 1978-2001 – 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 ----------------------------------------------------------------------------
423.50 f g 616.46 g
Creel and San Joaquin Freshwater Recreational ----- Linked site selection and ----- ----- 1988 -----
Loomis 1992 Valley, recreational hunting and trip count models
California areas fishing
combined
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
East-west difference due to different WTP estimates and marsh abundance levels.
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
Under the assumption of a unitary demand elasticity.
e
Consumer surplus per hunter day.
f
Mean of two differently specified models.
g
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.
13
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
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 $)
--------------------------------------------------------------------------------------------- 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)
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 $)
--------------------------------------------------------------------------------------------- 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)
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)
16
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 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
1,553d
Sathirathai Thailand Mangrove Direct and 988 various ----- ----- 1993 ----- 1,851
and Barbier wetland indirect use
2001 (timber,
fishing,
coastline
protection)
17
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 ----------------------------------------------------------------------------
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
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
18
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 ----------------------------------------------------------------------------
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.
19
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22