## The use of willingness-to-pay approaches in mammal conservation

PIRAN C. L. WHITE, ALISON C. BENNETT and EMMA J. V. HAYES Environment Department, University of York, Heslington, York YO10 5DD, UK

ABSTRACT With limited monetary resources available for nature conservation, policy-makers need to be able to prioritize conservation objectives. This has traditionally been done using qualitative ecological criteria. However, since declines in species and habitats are largely the result of socio-economic and political forces, human preferences and values should also be taken into account. An environmental economics technique, contingent valuation, provides one way of doing this by quantifying public willingness-to-pay towards specific conservation objectives.

In this paper, the use of this approach for quantifying public preferences towards the UK Biodiversity Action Plans for four different British mammal species is considered. The species included are the Red Squirrel Sciurus vulgaris , the Brown Hare Lepus europaeus , the Otter
Lutra lutra and the Water Vole Arvicola terrestris . Willingness-to-pay for conservation was increased by the inclusion of the Otter among the species, membership of an environmental organization and awareness of the general and species-specific threats facing British mammals. It was reduced by the presence of the Brown Hare among the species being
considered.

These findings for British mammals are compared with other willingness-to-pay studies for mammal conservation worldwide. Willingness-to-pay tends to be greater for marine mammals than terrestrial ones, and recreational users of species (tourists or hunters) are generally morewilling than residents to pay towards species conservation. The choice of technique for eliciting willingness-to-pay from respondents is also shown to be highly significant.

Willingness-to-pay values for British mammals derived from contingent valuation are sensitive to the species included rather than merely symbolic. This indicates that, with care, such measures can be used as a reliable means of quantifying public preferences for conservation,and therefore contributing to the decision-making process. However, irrespective of the internal consistency of contingent valuation, the validity of the approach, especially for use in nature conservation, is disputed. Willingness-to-pay is likely to reflect many interrelated factors such as ethical and moral values, knowledge and tradition, and monetary values may not be an adequate representation of these broader considerations. Willingness-to-pay approaches should therefore be used in addition to, rather than in place of, expert judgements and more deliberative approaches towards policy decision-making for conservation.

Keywords : economic value, willingness-to-pay, public preferences, contingent valuation, Red Squirrel, Brown Hare, Otter, Water Vole

Correspondence: Dr Piran White, Environment Department, University of York, Heslington, York YO10 5DD. Tel.: (01904) 434062. Fax: (01904) 432998. E-mail: PCLW1@york.ac.uk152 P

. C

.L. Whit e
, A. C

. Bennett and E. J

. V

. Ha y es

INTRODUCTION
Economic values and conservation For species or habitats that are threatened with extinction, ecological data are required for quantifying the extent of declines, as well as the underlying causes behind these declines.Where available, these data provide the foundation for species or habitat conservation management plans. However, with limited monetary resources available for conservation, policymakers need to be able to prioritize conservation objectives to determine how best to deploythe available resources. This has traditionally been done using qualitative ecological criteria, such as species richness, diversity and representativeness at different spatial scales(Spellerberg, 1992). Most current species and habitat declines are largely the result of socioeconomic and political forces. On this basis, some authors have argued that human preferences and values should also be taken into account in devising appropriate and effectiveconservation measures (Norton, 1986). This has increased emphasis on expressing the conservation benefits of particular species or habitats in economic terms.

The total economic value of an ecological resource incorporates not just its market economic value or direct-use value, such as any monetary value to be gained from it as food, skin or tourism, but also its non-market values, those which cannot be traded in markets and therefore which have no obvious price. Environmental valuation attempts to quantify thesenon-market values, which can then be combined with the market values to give a total economic value. Non-market values encompass indirect-use values (functional benefits such as nutrient recycling), option-use values (the benefit of retaining a resource so it may be used at some time in the future) and also non-use values (aesthetic and existence values) (Krutilla, 1967; Dixon & Sherman, 1990; Swanson & Barbier, 1992; Pearce & Moran, 1994). Although the process of deriving monetary values for non-market benefits of ecological resources is controversial (Rappaport, 1993), it provides one of the few methods by which the broader social benefits of these resources can be relatively easily quantified. Environmental valuation has therefore become increasingly recognized as a means of aiding policy decision-making regarding nature conservation (Department of the Environment, 1991, 1994; Hanley, 1995; Willis, 1995; Willis, Garrod & Shepherd, 1996; Bright & Halliwell, 1999).

In undertaking a conservation programme for a particular species or habitat, society may experience opportunity costs by having to forego benefits from alternative uses of land or investment of resources that might have yielded greater market economic benefits. Although a variety of techniques are available for environmental valuation, the only appropriatemethod for evaluating the anthropocentric benefits of potential future conservation programmes is the use of willingness-to-pay (Just, Hueth & Schmitz, 1982; Loomis & White,1996). By deriving willingness-to-pay values, different conservation scenarios can be compared to provide information for policy-makers on the relative value to society of the species
and habitats involved. Of the various methods available for the valuation of environmental goods, contingent valuation is the only one that incorporates non-use values directly, and these are likely to be important components of the overall value of threatened or rare species. Contingent valuation operates by setting up a hypothetical market, within which people are asked to state bids for various goods based on the information with which they are provided (Mitchell & Carson, 1989; Hanemann, 1995).

Objectives of this paper With the exception of some high profile bird species such as the Whooping Crane Grus

americana , the Bald Eagle Haliaeetus leucocephalus and the Northern Spotted Owl Strix
occidentalis caurina , and a few fish species, most of the work on willingness-to-pay forWillingness-to-pay for mammal conservation 153

species conservation has been concerned with mammals. In this paper, new data on public willingness-to-pay towards conservation of the Brown Hare Lepus europeaus and the Red Squirrel Sciurus vulgaris in the context of the UK Biodiversity Action Plans (Anon, 1995a,b) are compared with previously published data on the Otter Lutra lutra and the Water Vole
Arvicola terrestris (White et al ., 1997). An analysis is undertaken to investigate the underlying factors that determine willingness-to-pay for the conservation of these four species. Thewillingness-to-pay values obtained for these British mammals are then analysed in conjunction with those obtained for mammals from willingness-to-pay studies worldwide. Finally,the implications of using willingness-to-pay approaches, and particularly contingent valuation, in decision-making for nature conservation policy are discussed and recommendations
are made.

METHODS Questionnaire structure for the UK Biodiversity Action Plan study Data for this part of the study were collected by telephone surveys using a referendum approach as described by White et al . (1997). The sample frame was the population of thecounty of North Yorkshire. This limited sample frame was chosen to control for the possibility of region-specific differences in preferences for different species which, given constraints of sample sizes for the questionnaires, might have complicated the interpretation of the results. Six questionnaires were conducted: the first three in February–March 1996 and the second three in February–March 1997. The first three questionnaires dealt with the proposed Action Plans for the Otter and the Water Vole. The first concerned the Otter, the second the Water Vole and the third these two species together (White et al ., 1997). The fourth and fifth questionnaires were concerned with the Red Squirrel and Brown Hare, respectively, while the sixth dealt with all four species together. All six questionnaires were identical to each other in all aspects apart from the information specific to the particular species concerned. The general form of the questionnaires is shown as an Appendix in White et al . (1997).

Calculation of willingness-to-pay for the UK Biodiversity Action Plans Logistic regression was used to determine the significant factors affecting willingness-to-pay and to estimate median willingness-to-pay for the Red Squirrel, Brown Hare and four-species questionnaires. The variables used are shown in Table 1. The goodness-of-fit of the models was estimated using the maximum log-likelihood ratio. A total regional willingness-to-pay for the Action Plans was obtained by aggregation of the median willingness-to-pay values over the tax-paying population of the North Yorkshire region by multiplication. This figure represents the total present value of the Action Plans to the North Yorkshire population. In order to compare these figures with the costs of the Action Plans, the annual costs for the Action Plans for the years 1997, 2000 and 2010 (Anon, 1995b) were converted to single present values following the methods of White et al . (1997).

Factors affecting willingness-to-pay for the UK Biodiversity Action PlansA further analysis was undertaken to determine the important factors affecting willingnessto-pay for species conservation, combining the results from all six questionnaires. The data were used in a logistic regression model with willingness-to-pay (yes/no) as the dichotomousdependent variable. The independent factors were Brown Hare, Otter, Water Vole, Red Squirrel (all four as dummy variables, taking a value of 1 if the species was included among those being considered and 0 otherwise), Gender, Aware, Threat, Amount, Member, Walk, Income and Age.154 P.C.L. White, A.C. Bennett and E.J.V. Hayes

Comparison of Biodiversity Action Plan results with other studies worldwide There is considerable inconsistency in the manner in which willingness-to-pay is expressed between different studies. Some studies ask respondents to express their willingness-to-pay as an annual amount, whereas others (such as the present one) use a single lump sumpayment. In order to enable comparisons to be made between studies, all values were converted to the nearest US dollar, and annual values were converted into equivalent single lump sum payments according to the formula:

where PV ( X t ) is the present (lump sum) value of an annual payment X t , d is the discount rate expressed as a proportion and T is the time horizon in years where the summations run
from t = 0 (the first year of payment) to t = T (the last year of the project). Eagle & Betters (1998) used a 8% discount rate over 30 years to convert lump sum figures to an equivalent annual amount. The authors stated that this specific combination of discount rate and timeperiod were chosen for their particular study, and that other figures could be used if considered more appropriate. The standard UK government discount rate for environmental projects is 6%. However, respondents to questionnaires would tend to overestimate annual figuresfor willingness-to-pay relative to single one-off payments, and to underestimate their commitment to future payments. For this part of the study, we therefore used a discount rate of 8% and a time horizon of 10 years.

RESULTS Data from the UK Biodiversity Action Plan questionnaires The results from the first three Biodiversity Action Plan questionnaires have been presented previously by White et al . (1997). Of 862 telephone calls made for the fourth, fifth and sixth surveys, 450 questionnaires suitable for statistical analysis were obtained (Red Squirrel,

n = 150; Brown Hare, n = 150, both species together, n = 150), a response rate of 52.2%. This sample represents 0.08% of the total North Yorkshire population (Anon, 1991). The demographic structure of respondents was very similar to the previous study by White et al

. PV X X t t t

t T 

### ( 

### ) = + 

### ( 

### ) 

# [ ]

-

= 

## Â 1

0 d Table 1. Independent variables used in the logistic regression models for willingness-to-pay

Independent variable name Description

Gender Gender of respondent; dichotomous variable (male/female) Aware Awareness of the general fact that many British mammals are under threat from human activities; dichotomous variable (yes/no) Threat Awareness of specific nature of threats to the different species; dichotomous variable (yes/no)Amount The amount specified as a once-off tax supplement in the willingness-topay question; categorical variable (£1, £2, £5, £10, £20) Member Whether the respondent is a member of a conservation group or environmental organization; dichotomous variable (yes/no) Walk Whether the respondent walks frequently in the countryside; dichotomous variable (yes/no) Income Respondent’s household income grouping; categorical variable ( < £10 000, £10–20 000, £20–30 000, £30–40 000, > £40 000) Age Respondent’s age grouping in years; categorical variable ( < 20, 20–29, 30–39, 40–49, 50 + )Willingness-to-pay for mammal conservation 155

(1997). There was a significant difference in age structure between the survey sample and the North Yorkshire population (Table 2, c 2
= 31.44, d.f. = 4, P < 0.001) with age groups < 20 years and 20–29 years being under-represented. The telephone calls were answered by women 61.7% of the time. Of those answering the telephone, 52% of women refused to answer thequestionnaire, compared with 38% of men. Of all those who agreed to answer the questionnaire, 58.4% were female overall. There was no significant difference between the respondents to the three questionnaires in terms of gender (Table 2, c 2
= 4.08, d.f. = 2, NS), age (Table 2,

c 2
= 4.92, d.f. = 8, NS) or income (Table 2, c 2
= 4.79, d.f. = 8, NS). Of all the respondents,
63% had annual household incomes of < £20 000.

The behavioural and attitudinal characteristics of the respondents were very similar to the results from the study by White et al . (1997). Of all respondents, 66% said they walked frequently in the countryside, 20% were members of a conservation group or environmental organization, and 77% said that they were aware of the general fact that many Britishmammal species were under threat. Of the respondents to the two individual species questionnaires, 80% were aware of the specific threats to the Red Squirrel, compared with only
33% for the Brown Hare.

The proportion of respondents willing to pay varied widely across the three questionnaires, being 31% for the Brown Hare, 45% for the Red Squirrel and 62% for all four species together (Table 3). There was a general inverse relationship between willingness-to-pay and the amount specified for both the Brown Hare and Red Squirrel individually and all four species together, although the pattern of this decline was not continuous, especially for the Red Squirrel. The gender of the respondent had no effect on willingness-to-pay the amount specified for the Red Squirrel (males 44%, females 45%; c 2
= 0.05, d.f. = 1, NS) or all four species together (males 64%, females 61%; c 2
= 0.80, d.f. = 1, NS), but males were much more likely to be willing to pay the amount specified for the Brown Hare (males 42%, females 25%; c 2
= 9.33,
d.f. = 1, P < 0.01).

Respondents who were aware of the general threats to British mammals and those whowere aware of the specific threats to the different species were more willing to pay the specified amount towards the Action Plans than those who were not. Respondents who were Table 2. Comparison of gender, age and income structure of respondents for the three questionnaires in the present study

Questionnaire type

Brown Hare Red Squirrel All four Variable Category (%) (%) species (%)

Gender Male 35 47 43
Female 65 53 57 Age (years) < 20 32 27 31
20–29 30 37 34
30–39 21 18 19
40–49 10 11 6

> 50 7 7 10 Income (£) < 10 000 3 4 2
10–20 000 9 15 11
20–30 000 20 21 19
30–40 000 24 20 21

> 50 000 44 40 47156 P.C.L. White, A.C. Bennett and E.J.V. Hayes

members of a conservation or environmental organization or walked frequently in the countryside were also generally more likely to be willing to pay towards the Action Plans (Table 4).

Willingness-to-pay for the UK Biodiversity Action PlansFor the Brown Hare, the significant factors in the logistic regression model of willingness-topay were the amount specified, the gender of the respondent and membership of an environmental organization (Table 5). For the Red Squirrel, the significant factors were the amount specified, membership of an environmental organization and income. For the four species together, the significant factors were the amount specified and the awareness of the general threats to British mammals.

All three models were significant and were able to classify willingness-to-pay (yes/no) with an accuracy of almost 70% (Table 6). The median willingness-to-pay values calculated from the models were –£2.76 for the Brown Hare alone, £2.69 for the Red Squirrel alone and £20.54 for all four species together. However, since it is unlikely that there are people who would actually pay to avoid having the Action Plans instigated, the median willingness-to-pay from the Brown Hare has been truncated at zero. The median willingness-to-pay values obtained by White et al . (1997) were £11.91 for the Otter, £7.44 for the Water Vole, and £10.92 for the Otter and the Water Vole together.

If people under the age of 20 are excluded (as non-taxpayers), the aggregate willingnessto-pay values towards the Action Plans over the North Yorkshire population are £6.4 million Table 3. The effect of amount specified on the respondents’ willingnessto-pay towards the Action Plans for the Brown Hare, the Red Squirrel and all four species (Brown Hare, Red Squirrel, Otter, Water Vole) together

Willingness-to-pay (% of respondents)

Amount (£) Brown Hare Red Squirrel All four species

1 50 53 83
2 30 67 77
5 37 27 53
10 20 37 33
20 17 40 63
Overall 31 45 62

Table 4. The effects of respondents’ knowledge and behavioural characteristics on their willingness-to-pay a specified amount towards the Action Plans for the Brown Hare, the Red Squirrel and all four species (Brown Hare, Red Squirrel, Otter, Water Vole) together

Respondents willing to pay the amount specified (%)

Characteristic Knowledge/behaviour Brown Hare Red Squirrel All four species

Aware Yes 34 45 68
No 19 43 40
Threat Yes 38 47 64
No 27 37 55
Member Yes 44 65 69
No 27 40 60
Walk Yes 33 43 64
No 27 49 59Willingness-to-pay for mammal conservation 157

for the Otter, £4.0 million for the Water Vole (both from White et al ., 1997), £0 for the Brown Hare, £1.4 million for the Red Squirrel (both from the present study), £5.8 million for the Otter and Water Vole together (from White et al ., 1997) and £11.0 million for all four speciestogether. Table 7 compares these figures with the total present values of the different UKwide Action Plans. Table 5. Parameter estimates for the logistic regression models of willingness-to-pay for the Action Plans for the Brown Hare, Red Squirrel, Otter and Water Vole. Independent variables are described in full in Table 1. In these models, willingness-to-pay is the dichotomous (yes/no) dependent variable. For all models,

n = 150

Coefficient Standard error Significance Model Independent variable b ( ± ) ( P)

Brown Hare Gender

- 0.81 0.39 < 0.05
Member 0.86 0.43 < 0.05
Amount

- 0.09 0.03 < 0.01
Constant 0.08 0.38 NS Red Squirrel Age

- 0.32 0.15 < 0.05
Amount

- 0.04 0.03 < 0.1
Member 1.19 0.47 < 0.05
Income

- 0.30 0.16 < 0.05
Constant 1.82 0.75 < 0.05 All four species Amount

- 0.04 0.02 < 0.1
Awareness 1.13 0.42 < 0.01
Constant

- 0.06 0.42 NS

Table 6. Summary statistics and median willingness-to-pay derived from the logistic regression models for the Action Plans for the Brown Hare, Red Squirrel, Otter and Water Vole. The model c 2 is the difference between –2 log likelihood for the model with a constant only, and –2 log likelihood for the current model. It therefore tests the null hypothesis that the coefficients for all of the terms in the current model, except the constant, are zero. For all models, n = 150

Model Brown Hare Red Squirrel All four species

Model c 2 16.49 16.54 10.57 Significance ( P ) < 0.001 < 0.005 < 0.01
% correct classification 68.7 67.3 66.0 Median willingness-to-pay (£) 0.00 2.69 20.54

Table 7. Present values of the Action Plans for the Red Squirrel, the Brown Hare, the Otter, the Water Vole, the Otter and Water Vole together and all four species combined, compared with the willingness-to-pay values from this study and that of White et al . (1997) aggregated over the North Yorkshire population. The human population statistics have been taken from Anon (1991)

Present value of Action Aggregated willingness-to-pay over Plans (£ million) North Yorkshire population (£ million)

Red Squirrel 1.9 1.4
Brown Hare 0.4 0.0
Otter 0.8 6.4
Water Vole 1.0 4.0 Otter and Water Vole together 1.8 5.8 All four species combined 4.1 11.0158 P.C.L. White, A.C. Bennett and E.J.V. Hayes

Factors affecting willingness-to-pay for the UK Biodiversity Action Plans For the logistic regression analysis using the raw data from all six questionnaires ( n = 765), a backward stepwise procedure was used. Initially, all the remaining independent variables were included in the model (Table 8, Full Model). Following this, all factors that were not close to significance ( P > 0.1) were removed and a new ‘reduced’ model was developed. On each subsequent run, all factors that were not significant ( P > 0.05) were removed. Thisprocess resulted in Reduced Model I (Table 8). In this model, willingness-to-pay was positively related to the presence of Otters among the species considered, an awareness of general and species-specific threats and membership of an environmental organization, but negatively related to the presence of Brown Hares among the species being considered, the age of respondents and the amount of payment requested.

Although all the independent factors were significant in Reduced Model I, the constant

Table 8. Results of logistic regression models of factors determining willingness-to-pay using data from all three questionnaires in the present study combined with those in White et al . (1997). In these models willingness-to-pay is the dichotomous (yes/no) dependent variable. The variables, with the exclusion of the species dummy variables, are listed in Table 1, and the development of the models is described in detail in
the text. Values shown are the coefficients b ± their standard errors. The significance of the b -values is
shown in brackets below. The model c 2 is the difference between –2 log likelihood for the model with a constant only, and –2 log likelihood for the current model. It therefore tests the null hypothesis that the coefficients for all of the terms in the current model, except the constant, are zero. For all models, n = 765

Full Reduced Reduced Independent variable Model Model I Model II

Brown Hare

- 0.31 ± 0.17

- 0.31 ± 0.16 (0.06) (0.053) Red Squirrel 0.18 ± 0.18 (0.30)
Otter 0.71 ± 0.18 0.85 ± 0.16 0.82 ± 0.16 ( < 0.001) ( < 0.001) ( < 0.001)
Water Vole 0.29 ± 0.18 (0.01)
Gender 0.22 ± 0.16 (0.17)
Aware 0.56 ± 0.20 0.56 ± 0.19 ( < 0.01) ( < 0.01)
Threat 0.32 ± 0.18 0.39 ± 0.17 0.50 ± 0.16 (0.08) (0.02) ( < 0.005)
Member 0.74 ± 0.21 0.73 ± 0.20 0.78 ± 0.20 ( < 0.001) ( < 0.001) ( < 0.001)
Walk 0.14 ± 0.17 (0.43)
Income

- 0.09 ± 0.07 (0.19) Age

- 0.28 ± 0.07

- 0.26 ± 0.07

- 0.25 ± 0.07 ( < 0.001) ( < 0.001) ( < 0.001)
Amount

- 0.08 ± 0.01

- 0.08 ± 0.01

- 0.08 ± 0.01 ( < 0.001) ( < 0.001) ( < 0.001)
Constant 0.50 ± 0.41 0.54 ± 0.32 0.72 ± 0.30 (0.22) (0.10) ( < 0.05)
Model c 2 131.69 123.83 112.35
d.f. 12 7 5 Significance ( P ) < 0.001 < 0.001 < 0.001
% correct classification 65.62 66.27 65.36Willingness-to-pay for mammal conservation 159

was not significant at P £ 0.05. A further reduced version of the model was therefore developed by removing the least significant independent variables in turn to attempt to increase the significance level of the constant, but at the same time ensuring that all independent factors remaining in the model were significant at P £ 0.05. This process resulted in Reduced Model II (Table 8). In this model, willingness-to-pay was positively related to the presence ofOtters among the species considered, an awareness of species-specific threats and membership of an environmental organization, but negatively related to the age of respondents and the amount of payment requested.

Comparison with other willingness-to-pay studies worldwide Table 9 sets out the results of previously published willingness-to-pay studies on mammals including the present one, with values expressed as single lump sums to the nearest US dollar. Even with the relatively short time horizon used here of 10 years, studies for which lump sums were derived from annual willingness-to-pay figures still dominate the top half of Table 9, which suggests that this conversion is, if anything, rather conservative.

The lack of consistency of questionnaire format and information provided to respondents across the different studies in Table 9 precludes any detailed quantified analysis of the role of ecological factors in determining willingness-to-pay. However, it is possible to compare other components of the studies. Based on the results for the single species studies only,willingness-to-pay for conservation is significantly greater for marine mammals than terrestrial ones ( U 9, 14 = 21, P < 0.05) and for questionnaires using either open-ended or payment card formats than those using dichotomous choice ( U 12, 11 = 28, P < 0.05). There was no significant difference in willingness-to-pay between residents and visitors ( U 4, 17 = 23, N

. S .),although if hunters were included with visitors as a group more likely to have a large recreation component to their total value, the difference was almost significant ( U 6, 17 = 23, P < 0.1).

DISCUSSION Single and multispecies results for the UK Biodiversity Action Plans The results of the present study and that of White et al . (1997) show that the North Yorkshire public were willing to pay significant amounts towards the Action Plans for the Otter, the Water Vole and the Red Squirrel. The factors that were significantly associated with willingness-to-pay in the individual species logistic regression models were the amount ofmoney involved, membership of an environmental organization, awareness of the speciesspecific threats, and income. Willingness-to-pay for the Otter Action Plan far exceeded that of any other species considered. This result is not unexpected since the Otter has been one of the most high-profile single-species conservation causes in Britain.

The lack of willingness-to-pay towards the Brown Hare Action Plan in this study may be due partly to the fact that, although Brown Hares are in decline overall in Britain, this hides quite substantial regional differences. The long-term decline has been most apparent in western, pastoral areas (Hutchings & Harris, 1996), although over the last decade there havealso been declines in arable areas in southern England, north-east England and coastal Scotland. Nevertheless, Brown Hares still remain at significantly higher densities in these landscapes than in western, pastoral ones (R. Temple, S. Clark & S. Harris, unpublished data), and in some parts of these areas they may be considered as agricultural pests. The area covered by the questionnaires in this study was an eastern, predominantly arable one, and therefore some bias amongst the respondents against Brown Hares within the local area could have had an effect on the results. A sample population from another area of the country might have yielded different results for the Brown Hare.160 P.C.L. White, A.C. Bennett and E.J.V. HayesTable 9.Economic values for threatened mammals obtained from various studies, shown in order of declining willingness-to-pay. Values are shown to the nearest US dollarequivalent (£UK1=$US1.6). Where annual values are shown, these form the basis of the single sum equivalents. In these cases, single sum values have been derived fromannual values by assuming that annual payments are made for a period of 10 years and using a 8% discount rate (see text for details)Proposed changeWillingness-to-payNature of proposed in population($US)SampleSpecies Country change to population size (%) Annual Single sum population ReferenceGrizzly Bear US Gain for hunting – 37 268 Hunters Brookshireet al. (1982)GrayWhale US Gain 100 32 232 Visitors Loomis & Larson (1994)Bighorn Sheep US Gain for hunting – 30 217 Hunters Brookshireet al. (1982)GrayWhale US Gain 50 27 196 Visitors Loomis & Larson (1994)GrayWhale US Avoid loss – 24 174 Residents Hageman (1985)Humpback Whale US Avoid loss – – 173 Residents Samples & Hollyer (1989)Sea Otter US Avoid loss 100 21 152 Residents Hageman (1985)GrayWhale US Gain 100 19 138 Residents Loomis & Larson (1994)Bottlenose Dolphin US Avoid loss – 19 138 Residents Hageman (1985)Northern Elephant Seal US Avoid loss – 18 130 Residents Hageman (1985)GrayWhale US Gain 50 17 123 Residents Loomis & Larson (1994)Monk Seal US Avoid loss – – 120 Residents Samples & Hollyer (1989)GrayWolf US Reintroduction – – 118 Visitors Duffield (1992)Bighorn Sheep US Avoid loss – 12 87 Residents King, Flynn & Shaw (1988)GrayWolf US Reintroduction – – 70 Visitors Duffield (1992)Otter UK Biodiversity Action Plans 25 – 33 Residents Present studyWater Vole 25–50Red Squirrel 25–50Brown Hare 100GrayWolf US Reintroduction – – 27 Residents Duffield, Patterson & Neher (1993)GrayWolf US Reintroduction – – 21 Residents US Department of the Interior(1994)Otter UK Biodiversity Action Plan 25 – 19 Residents Whiteet al. (1997)Otter UK Biodiversity Action Plans 25 – 17 Residents Whiteet al. (1997)Water Vole 25–50GrayWolf US Reintroduction – – 16 Residents US Department of the Interior(1994)Pine Marten UK Reintroduction – – 16 Residents (farmers) Bright & Halliwell (1999)Pine Marten UK Reintroduction – – 13 Residents (public) Bright & Halliwell (1999)Water Vole UK Biodiversity Action Plan 25–50 – 12 Residents Whiteet al. (1997)Red Squirrel UK Biodiversity Action Plan 25–50 – 4 Residents Present studyBrown Hare UK Biodiversity Action Plan 100 – 0 Residents Present studyWillingness-to-pay for mammal conservation 161

However, there may also be other more general factors contributing to the lack of willingness-to-pay towards Brown Hare conservation. The Brown Hare has emerged as a species of conservation concern only relatively recently. The significance of the awareness of threats to specific species in the multiple regression model for willingness-to-pay provides somesupport to this argument, since only 33% of people answering the Brown Hare questionnaire were aware of the specific threats to this species. This lack of public awareness and willingness-to-pay also corresponds with a lack of consistent commitment to Brown Hareconservation at a local level. For example, only 14 out of 45 published or draft local Biodiversity Action Plans produced between 1995 and 2000 contained Species Action Plans for Brown Hares, despite Brown Hares being uncommon or rare in 30 of the 45 areas (S. Harris, unpublished data). Moreover, the presence of local Species Action Plans for the Brown Hare does not show any consistent relationship with Hare population status among these local areas. On this evidence, the lack of willingness-to-pay for Brown Hare conservation found in the present study may not represent a specific regional bias, but in fact be representative of the situation nationally regarding Brown Hare conservation. One reason for this may be that Brown Hares are considered as a game species. Many local Biodiversity Action Plans cite hunting as a reason for the species’ decline. The worldwide analysis showed that hunters tendto be more willing to pay for conservation of species that they can hunt. However, the corollary is also likely to be true, i.e. non-hunting conservationists are less likely to be willing-topay for the conservation of species that other interest groups will then hunt.

When two or more species were considered together in the present study, the willingnessto-pay value was in one case (Otters and Water Voles) very similar to the value for the highestof the individual component species, and in the other case (Otters, Water Voles, Red Squirrels and Brown Hares) very similar to the sum of the individual willingness-to-pay scores for all the component species (£20.54 obtained from the four-species questionnaire comparedwith an aggregate value of £22.04). These results suggest that the respondents were providing scaled responses relative to the magnitude of the conservation benefits rather than simply providing a symbolic ‘warm glow’ response, a criticism often levelled at contingent valuation (Kahneman & Knetsch, 1992).

Aggregated willingness-to-pay values for the UK Biodiversity Action PlansBecause of the potential biases arising from the geographical area over which the questionnaires were conducted, aggregation of the median willingness-to-pay values has beenrestricted to the sample population of North Yorkshire rather than over the entire population of Great Britain. This inevitably means that the aggregated willingness-to-pay values obtained from this study are not equivalent to the net present values of the Action Plans for the different species published by the Biodiversity Steering Group. Nevertheless, it is stillinformative to compare the two sets of figures. For the Otter and the Water Vole, the aggregate willingness-to-pay values over the North Yorkshire population exceeded the presentvalue of the UK-wide Action Plan by eight and four times, respectively. The willingness-topay for the Red Squirrel Action Plan was just under 75% of the present value of the UK Action Plan for this species, and the willingness-to-pay for the Brown Hare was zero. For the Otter and Water Vole combined, the aggregate North Yorkshire willingness-to-pay value wasover three times that of the UK-wide present value of the plans, and for all four species combined, the aggregate willingness-to-pay value was over two and a half times greater than the UK-wide present value of the plans.

In any questionnaire of the type used in relation to the Biodiversity Action Plans for the Otter, the Water Vole, the Red Squirrel and the Brown Hare, respondents are inevitably self-162 P.C.L. White, A.C. Bennett and E.J.V. Hayes

selecting to a degree and this may lead to biases in the data obtained. Because the preferences of non-respondents are, by definition, unknown, it is very difficult to predict the precise nature of these biases. However, it is likely that the 20% of respondents who were membersof an environmental organization is higher than the general population, and so the willingness-to-pay values derived are probably also slightly higher than would be a true figure forthe whole population. However, even allowing for these biases and the other reasons for overestimates often associated with willingness-to-pay studies, the very high values obtained in the Biodiversity Action Plan surveys reported here indicate considerable public support for the Plans. The detailed analysis shows that for the four species considered, the plan for theOtter received the greatest support, and that for the Brown Hare the least. The economic conclusion from this is that the greatest gain in public welfare for the North Yorkshire population would be achieved by investing most in Otter conservation, relatively less in Water Vole and Red Squirrel conservation, and none in Brown Hare conservation.

Factors affecting willingness-to-pay for the UK Biodiversity Action Plans The hierarchical structure of the questionnaires in the present study enabled the effects of different species and related ecological characteristics on the overall willingness-to-pay to be considered explicitly. Although comparisons of this type have been attempted before (Loomis& White, 1996), the present study represents the first where the data were collected in a consistent manner precisely for the purpose. The analysis of the UK Biodiversity Action Plansurveys revealed that willingness-to-pay was significantly related to the presence of particular species among those being considered as well as to the characteristics of respondents. The presence of the Otter significantly increased willingness-to-pay. This finding confirms the importance of such flagship species in gaining support for conservation projects (White et al

., 1997).

Samples et al . (1986) found that physical appearance of the species was a significant factor affecting willingness-to-pay, although when information on endangered status was revealed at the same time, this affected the values accorded to different species. Metrick & Weitzman (1996) conducted a statistical analysis of actual US government expenditure on endangered species conservation in relation to a combination of ‘scientific’ characteristics, such as the degree of threat and taxonomic uniqueness and ‘visceral’ characteristics such as physical size, taxonomic group and charisma. They found that the role of ‘visceral’ characteristics was much greater than ‘scientific’ ones in determining public expenditure. This seems to accordwith wider information for the UK, and is paralleled by the importance of a single charismatic species in determining public willingness-to-pay in the present study.

Willingness-to-pay for the UK Biodiversity Action Plans was also positively related to awareness of general and species-specific threats facing British mammals and membership ofan environmental organization. These results are not unexpected but they confirm the importance of providing information in gaining support for conservation. The reasons for the negative relationship between Brown Hares and willingness-to-pay have been discussed above. However, this result provides further confirmation that respondents were actually assessing what they were being asked rather than simply providing a symbolic response. The negative relationship between willingness-to-pay and age is likely to be a result of the fact that younger people are generally more environmentally aware than older generations, although it couldalso be argued that younger people may be more idealistic and have fewer financial responsibilities than older people. If this is the case, the higher willingness-to-pay of younger people may be an artefact of the hypothetical nature of the method used rather than a genuine phenomenon.Willingness-to-pay for mammal conservation 163

Worldwide use of willingness-to-pay in mammal conservation Loomis & White (1996) used data from some of the studies summarized in Table 9, together with some studies on birds and fish, in a multiple regression model of factors affecting willingness-to-pay. They found that the type of species was a significant factor, with marine mammals and birds both leading to an increased willingness-to-pay in the model, and that increased willingness-to-pay was linked with whether the sample frame consisted of visitors rather than residents. They concluded that willingness-to-pay tended to be greater when payment took the form of a single lump sum rather than an annual payment. However, their analysis did not include any standardization of the raw willingness-to-pay data, whether in terms of single payments (as in the present study) or annual figures (as in Eagle & Betters, 1998). The evidence from the present study suggests that in fact, when payment types are standardized, annual figures tend to provide higher willingness-to-pay values than single one-off payments. Loomis & White (1996) also found that willingness-to-pay was positively related with the proposed size of change in the population. These authors argued that willingness-to-pay results were therefore not merely symbolic but sensitive to the magnitude of changes proposed. This corresponds to the results of the UK Biodiversity Action Plan studies reported here.

Samples et al . (1986) hypothesized that when respondents are informed of the endangered status of a species, the expressed valuation is largely a non-use existence value. In the present study, awareness of general and species-specific threats and regular recreational use of the countryside were all positively related to willingness-to-pay for species conservation. Whilst existence value is likely to have been important in determining willingness-to-pay in this study (since these interest groups would hold higher existence values for these species relative to the general population), the results also imply the presence of a significant use value, probably expressed through recreational viewing of the species. This view is reinforced by the trendtowards greater willingness-to-pay of visitors or hunters (both recreational users of the countryside) compared with residents as shown in the comparison of the present UK study with
various other studies.

This finding is perhaps not surprising since the use value these people experience will be in addition to the other economic values held by the rest of society for a particular species.However, it may be very relevant for policy in that user groups will be more likely to be willingto-pay for conservation in practice as well as in theory. This difference also highlights another factor relating to ownership or management of a wildlife resource. Although a wildlife resource itself, in most cases, is technically owned by no one, exploitation or use of the resource is determined by the property rights of the land (or sea) where it is found. This is of particular importance for terrestrial species in countries such as the UK, where very little of the land is in public ownership. In these situations, landowners and farmers have considerable influence on the management and conservation of such species. In studies of willingness-to-pay for conservation, especially where the conservation objectives are local and linked closely with land management in a specific area, it is therefore preferable either to consider the views of different sectors of society explicitly (e.g. Bright & Halliwell, 1999)or at least to include the relevant information as a potential factor affecting willingness-topay in any model produced.

Policy relevance of willingness-to-pay studies for nature conservation Although contingent valuation has been used extensively in policy-related research to estimate environmental costs and benefits, there is much debate over the reliability of willingness-to-pay estimates provided by the technique. One of the major problems is that,164 P.C.L. White, A.C. Bennett and E.J.V. Hayes

when faced with a situation involving a hypothetical payment, people tend to overestimate their willingness-to-pay. Thus, willingness-to-pay values may overestimate genuine economic commitment. For example, Loomis et al . (1996) found that hypothetical willingness-to-pay was two times larger than real willingness-to-pay, and Neill et al . (1994) found it to be approximately nine times larger.

For hypothetical environmental valuation methods such as contingent valuation to be used within a cost–benefit analysis for policy, the figures they produce need to be reliable. The biases inherent in them need to be identified, and measures taken to eliminate them and thereby reduce internal inconsistency. Unfortunately, this is not a simple problem, and there is a large body of economic research concerned with identifying and quantifying the biases in the technique (e.g. Neill et al ., 1994; Loomis et al ., 1996; Foster, Bateman & Harley, 1997). Even if the estimates of economic value obtained by hypothetical willingness-to-pay studies differ from those revealed by actual economic behaviour, these methods still provide a means by which preferences can be quantified and alternative strategies compared relative to one
another.

Internal consistency is obviously an important factor in the use of these methods, but perhaps an even more important question from the policy perspective is the actual validity of the approach itself. This has been the focus of relatively less research attention. Clark et al

. (2000) investigated the views of respondents following a contingent valuation study to elicit willingness-to-pay for a Wildlife Enhancement Scheme for the Pevensey Levels, an area of wet grazing marsh on the south coast of England. Their study found that most respondents felt that the willingness-to-pay figure they had given in the survey was not a good measure of what the Levels were actually worth to them. Many of them thought it inappropriate that a monetary value should be used as a measure of what they saw as their ethical or moral values, and that asking individuals how much they were willing to pay was not a satisfactory way of informing choices of resource allocation for nature conservation (Clark et al . 2000).Another follow-up study by Vadnjal & O’Connor (1994), in this case concerning willingnessto-pay to preserve a particular island view from Auckland in New Zealand, also showed that the majority of respondents did not consider the willingness-to-pay value as an accurate measure of the value to them of maintaining the view. In contrast, Brouwer et al . (1999) found that 75% of their respondents were happy with using monetary terms to express their willingness-to-pay for a flood alleviation scheme on the Norfolk Broads, a series of lakes and waterways in eastern England, and that 67% felt the results of the willingness-to-pay survey would be useful to policy-makers. The applicability of contingent valuation to policy for nature conservation is therefore disputed.

The hypothetical nature of the contingent valuation approach and the fact that manyrespondents have conceptual difficulties in considering environmental goods directly in monetary terms has led to the development of alternative, indirect techniques such as contingent ranking and contingent rating (Beggs et al ., 1981; Mackenzie, 1993; Garrod & Willis, 1997).These approaches also have an advantage over contingent valuation of allowing the valuation of multi-attribute goods. Respondents are offered a number of alternative scenarios that include varying levels of environmental variables and a monetary variable, and are asked to rank or rate these alternatives. In these methods, respondents do not therefore make any direct valuation of environmental goods, but instead make trade-offs between the environmentaland the monetary attributes. These trade-offs are then used to derive preferences or valuations for the environmental variables indirectly. This technique has been used recently to inform decision-making for wildlife management policy in Britain (Cox, 1999; Cox et al

., 1999; White & Whiting 2000), although its wider applicability for valuation is dependent onWillingness-to-pay for mammal conservation 165

the existence of meaningful environment–monetary trade-offs for the construction of the alternative policy scenarios.

The order of preferences obtained from the UK Biodiversity Action Plan surveys clearlyreflects the popularity of charismatic species such as the Otter at the expense of less charismatic ones such as the Brown Hare. Indeed, if certain other, less charismatic species had been included, such as various species of bats, these may well have done fairly badly in terms of willingness-to-pay as well. The fact that popularity of key species is of overriding importancein determining willingness-to-pay is an important consideration for the wider use of willingness-to-pay approaches in policy. Less charismatic species will always do less well in thesesurveys, but may be under a relatively greater level of threat or of more biological significance in the ecosystem than some more charismatic species. Attaching too much emphasis to willingness-to-pay studies in nature conservation policy would therefore be at the expense of the less charismatic species and would probably lead to the inappropriate allocation of resources from a scientific perspective.

The results from the UK Biodiversity Action Plan surveys and those from the other studies worldwide indicate that scientific considerations are relatively much less important than charismatic ones in determining willingness-to-pay. The realization that willingness-to-pay values do not reinforce scientific knowledge often leads to dismissal of willingness-to-pay approaches. However, personal preferences are influenced by many factors including moral and ethical issues, culture and tradition, and scientific considerations are only one factor. It is therefore perhaps not surprising that public preferences towards conservation may oftenappear incoherent. As long as monetary values are deemed an appropriate means of encapsulating all these complex factors affecting preferences, this does not by itself invalidate the willingness-to-pay approach. However, understanding how preferences are formed should also be an important part of policy formulation and development. For example, one key factor that emerges as important in many studies is the degree of information or knowledge of the respondents. The high value attached to the Otter may well reflect, at least in part, the publicity accorded to Otter conservation programmes over the last 20 years. The Otter population is now in relatively less conservation need than the Brown Hare, the Water Vole or the Red Squirrel. However, this was not reflected in the willingness-to-pay values obtained, and this may be partly due to a lack of information. Indeed it could be seen in some ways as a failure of nature conservation organizations to convey the appropriate conservation message. Similarly, whilst the science of nature conservation is moving away from single species approaches, it may be that the public still finds it easier to perceive conservation in such terms. The single-species approach does not necessarily conflict with the objectives of community or ecosystem-based approaches due to the wider benefits seen through habitatconservation, but too much emphasis on ‘biodiversity’ may be at the expense of public understanding of individual species’ ecology and conservation.

Recommendations for the use of willingness-to-pay in conservation policy In the context of very real constraints on public expenditure on wildlife issues in countries throughout the world, willingness-to-pay techniques are becoming increasingly important as a supplement to scientific opinion in helping to determine objectives and priorities in natureconservation. Because of the many factors that can affect the internal validity and consistency of willingness-to-pay values, comparisons between different studies should be viewed with considerable caution. More importantly, it should also be remembered that in some cases, the respondents themselves may not have much faith in the values they provide. Where questionnaires are carefully constructed and respondents are sufficiently informed,166 P.C.L. White, A.C. Bennett and E.J.V. Hayes

willingness-to-pay values can provide a useful means of quantifying preferences between alternative conservation strategies. However, willingness-to-pay values are the result of complex interrelationships between many other factors including cultural and ethical ones, and the values should always be considered within the context of these other factors. In the future, new developments in techniques, such as contingent ranking and contingent rating, may provide more realistic values for non-market commodities. However, whatever economic valuation techniques are adopted, it should always be remembered that they are designed to assist rather than supplant political judgements. Techniques such as contingent valuation donot by themselves represent a complete and satisfactory solution to the problem of allocating scarce resources and they should be used in addition to, rather than instead of, expert judgements and more deliberative, community-based approaches at a local level.

ACKNOWLEDGEMENTS We would like to express our thanks to the members of the general public who participated in the survey. We are grateful to Jack Pezzey, Nancy Bockstael and Ivar Strand for comments and advice received at various stages of the work. Comments by Derek Yalden, StephenHarris and two anonymous referees greatly improved the manuscript. Emma Hayes was supported by a Natural Environment Research Council Research Masters Training Award.

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Submitted 28 August 1999; returned for revision 5 April 2000; revision accepted 3 August 2000