17.3 Using a Contingent Value Methodology Survey
Policy makers need to decide whether or not the damage caused by invasive
species, such as A. saligna, justifies the expense of controlling them. Ecologists
must be able to express the benefits of the expenditure on management and conservation of ecological resources in terms of goods and services to the public
(Richardson and van Wilgen 2004).
The most common tools used to estimate the value of public goods, such as
nature reserves, open spaces, and biodiversity, are the contingent valuation method
(CVM) and the travel cost method (Maille and Mendelsohn 1993; Carson 2000;
Hackett 2000; Jakobsson and Dragun 2001; Carson et al. 2003; Becker et al. 2007).
Contingent valuation methodology is a survey method that asks the respondent
to express how much he or she is willing to pay for a nonmarket environmental
good or service. This method is used to determine how people value environmental
goods and services through direct questioning and the benefits are therefore
measured directly. The assumption is that individuals have hidden preferences
(detected from their behavior), which they will reveal when questioned about their
preferences. This is the only method available to estimate non-use or passive use
value (sometimes referred to as existence value, first mentioned by Krutilla 1967)
(Carson 2000; Jakobsson and Dragun 2001; Carson et al. 2003).
The basic problem confronted by the research was the difficulty in explaining
the complexity of biodiversity loss to the unaware public so that informed answers
could be collected. If the respondents to a CVM survey are unaware of the
importance of the goods that they are being asked to value, they may not reveal a
strong preference and the good may be undervalued (Carson et al. 2000; Christie
et al. 2006).
17.3.1 Contingent Value Methodology Survey Design
In order to determine the economic benefit of controlling A. saligna or the
economic damage caused to the biodiversity of the coastal sand dunes at Nizzanim
Nature Reserve by the invasion of the species, a CVM survey of 404 Israelis was
conducted. There were two groups of respondents, from which an overall response
rate of 80 % was achieved. One group consisted of 113 visitors to the Nizzanim
LTER Coastal Sand Dune Nature Reserve. The second group consisted of 291
respondents from all over Israel. The purpose of surveying these two groups was to
compare the answers of users and non-users.
Owing to incomplete surveys and ‘‘protest’’ answers (a protest answer is a zero
value given by the respondent that indicates non-acceptance of the constructed
scenario); the results of 103 surveys were removed from the data, leaving 301
surveys for analysis.
276
D. Lehrer et al.
Policy makers need to decide whether or not the damage caused by invasive
species, such as A. saligna, justifies the expense of controlling them. Ecologists
must be able to express the benefits of the expenditure on management and conservation of ecological resources in terms of goods and services to the public
(Richardson and van Wilgen 2004).
The most common tools used to estimate the value of public goods, such as
nature reserves, open spaces, and biodiversity, are the contingent valuation method
(CVM) and the travel cost method (Maille and Mendelsohn 1993; Carson 2000;
Hackett 2000; Jakobsson and Dragun 2001; Carson et al. 2003; Becker et al. 2007).
Contingent valuation methodology is a survey method that asks the respondent
to express how much he or she is willing to pay for a nonmarket environmental
good or service. This method is used to determine how people value environmental
goods and services through direct questioning and the benefits are therefore
measured directly. The assumption is that individuals have hidden preferences
(detected from their behavior), which they will reveal when questioned about their
preferences. This is the only method available to estimate non-use or passive use
value (sometimes referred to as existence value, first mentioned by Krutilla 1967)
(Carson 2000; Jakobsson and Dragun 2001; Carson et al. 2003).
The basic problem confronted by the research was the difficulty in explaining
the complexity of biodiversity loss to the unaware public so that informed answers
could be collected. If the respondents to a CVM survey are unaware of the
importance of the goods that they are being asked to value, they may not reveal a
strong preference and the good may be undervalued (Carson et al. 2000; Christie
et al. 2006).
17.3.1 Contingent Value Methodology Survey Design
In order to determine the economic benefit of controlling A. saligna or the
economic damage caused to the biodiversity of the coastal sand dunes at Nizzanim
Nature Reserve by the invasion of the species, a CVM survey of 404 Israelis was
conducted. There were two groups of respondents, from which an overall response
rate of 80 % was achieved. One group consisted of 113 visitors to the Nizzanim
LTER Coastal Sand Dune Nature Reserve. The second group consisted of 291
respondents from all over Israel. The purpose of surveying these two groups was to
compare the answers of users and non-users.
Owing to incomplete surveys and ‘‘protest’’ answers (a protest answer is a zero
value given by the respondent that indicates non-acceptance of the constructed
scenario); the results of 103 surveys were removed from the data, leaving 301
surveys for analysis.
276
D. Lehrer et al.