Luis E. Santiago
University of Puerto Rico
John Loomis
Colorado State University
Society for Conservation Biology 2008
Annual Meeting
July 16, 2008
Chattanooga, Tennessee
This material is based upon work supported by the
National Science Foundation under Grant No. 0308414.
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Past studies only provided value per visitor
day for all or nothing decisions (close site, strip
mine it)
Our study provides valuation information on
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Site characteristics that could be provided by
management at a cost:
 Trails, campsites, parking, etc.
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Routing of roads and trails to scenic features such as
waterfalls
 Topography may make road or trail building more
expensive
 Waterfalls are coveted for small head hydropower
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Contingent Valuation Method (CVM) is
capable of monetizing the economic values of
instream flow and water-based recreation
(Cameron 1993; Loomis 2000)
Past stated preference valuation studies asked
respondents a series of WTP questions to
estimate change in recreation value with site
attributes (Holmes and Adamowicz 2003;
Hanley & Ruffel 1993; Walsh et . Al. 1989)
Our approach requires asking respondents a
single CVM question to value site attributes
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Information Component of Survey Instrument
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Item to be valued: recreation site
Payment vehicle: recreation trip cost
Time frame of payment: one-time
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Contingent Valuation Question
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Response format: Dichotomous-choice
Question: As you know the price of gasoline often goes
up. Taking into consideration that there are other rivers as
well as beaches nearby where you could go visit, if the cost
of this visit to this river was $____ more than what you
have already spent, would you still have come today?
____ Yes
____ No
The bid amount presented to respondents began at
$5, increased by multiples of 5 to $160.
35 respondents evaluated each bid amount.
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Probability (YES) = 1 - {1 + exp[β0 β1(X) + βA (A) + βD (D)]}
where
β0 = the intercept
β1 = the coefficient on the bid variable
X = the given bid amount
βA = the coefficient on the built and natural site
attributes (An)
βD = the coefficient on the demographic
variables (Dn)
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Conversion of Logit coefficients into WTP
equation and marginal values:
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Statistical analysis: Logit Model
Convert Logit coefficients to WTP equation using
Cameron reparameterization to calculate marginal
values
 Divide all coefficients through by coefficient on bid
amount
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(WTPit = f(A1i, . . . , Ani, D1i , . . . , Dni )
WTPit = net benefits (willingness to pay) from recreation
experience
A1i, . . . , Ani = built and natural site attributes such as scenic
views, the presence of waterfalls, availability of parking spots and
the presence of foot trails
D1i, D2i , . . . , Dni = demographic characteristics of the visitor,
including gender, age, level of education, and annual income
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i = individual respondent to survey
t = date
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Sample size
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984 questionnaires
99% response rate
Data Collection Mode
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In-person interviews at recreation site while visitors
were recreating
The interviewers were trained graduate and
undergraduate students who closely followed a
script
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Three watersheds in
northeastern Puerto Rico
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River
Espíritu Santo
Fajardo
Mameyes
164
229
591
Presence of Waterfalls
3 of 5 sites
1 of 3 sites
2 of 5 sites
Presence of Formal Trails
2 of 5 sites
0 of 3 sites
3 of 5 sites
Male
63%
50%
48%
Female
37%
50%
52%
12.6
13.0
13.3
Number of Observations
Natural and Built Site Variables
Socio-Economic Variables
Gender
Average Education Level
(in years)
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Variable
Coefficient z-Statistic
Prob.
Constant
1.1375
5.572
0.000
BID ($)
-0.0094
-13.59
0.000
WATERFALL
0.2126
2.1485
0.032
FOOT TRAILS
0.1774
1.6924
0.091
EDUCATION
-0.0234
-1.6865
0.092
GENDER
0.1775
2.154
0.031
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CONSTANT
WFALL
FTRAILS
1.1375
0.2126
0.1773
CONSTANT
$ 122.31
WFALL
$ 22.86
FTRAILS
$ 19.06
EDUC
-0.0234
EDUC
- $2.51
GENDER
0.1775
GENDER
$ 19.08
BID
-0.0093
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The median net economic value of a visit to the
three rivers without waterfalls or foot trails is
$96
Recreation at rivers with both waterfalls and
foot trails has a median value of $138 per trip
The presence of waterfalls accounts for $23 and
foot trails $19 per trip
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This information can be pertinent for managers
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Selecting recreation site locations
Protecting sites from competing uses, such as
locations with sufficient gradient for waterfalls, also
coveted by others for hydropower development
Improving existing site facilities
 Only 5 of 13 sites have formal trails
 Some sites, especially outside the CNF, don’t have
adequate parking, picnic areas , regular trash collection
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The natural and built attributes of these river
recreation sites provide an economically
valuable recreation experience to visitors
There is a substantial economic value even if
there is little direct cash flow to the U.S. Forest
Service , the Commonwealth of Puerto Rico, or
its municipalities
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