The economic value of botanic gardens: a recreational perspective

Geoforum. Vol. 24, No. 2, pp. 215-224, 1993 0016-7185i93 $6.C0+0.00

Printed in Great Britain 0 1993 Pergamon Press Ltd

The Economic Value of Botanic Gardens: a Recreational Perspective

GUY GARROD,* ANNE PICKERING? and KEN WILLIS,* Newcastle upon Tyne, U.K.

Abstract: Historically, the importance of botanic gardens was based on their status as centres for the study and understanding of plants, and on their usefulness to the developing science of medicine. Recently, however, these traditional uses of botanic gardens have diminished, and, with maintenance costs often exceeding revenues, their continued existence is under question. Using data on visitors to four very different botanic gardens, this study adopts a travel-cost methodology to estimate the economic benefits which they provide in their role as recreational facilities. These benefits are then aggregated and found to fall far short of the total grant-in-aid made to each garden, though it is noted that there are other considerations which need to be taken into account before any firm conclusions can be drawn about the gardens’ continued economic viability.

Introduction

The next decade will be crucial in deciding the future

of Britain’s botanic gardens. Faced with rising costs

and the decline of their traditional roles in medicine

and pharmacy, botanic gardens will, more than ever

before, have to provide a convincing justification for

the expenditure of the large sums of public money needed to maintain them. Unlike their counterparts in the United States and some European countries, most botanic gardens in Britain have eschewed the profitable cultivation of horticultural hybrids and varieties, allowing horticultural gardens, such as those at Wisley and Harrogate, to take advantage of the major increase in spending on leisure gardening and plants in the 1970s and 1980s. Instead they have concentrated on filling the more important, though

*Countryside Change Unit, Department of Agricultural Economics and Food Marketing, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K. TDepartment of Agricultural Biochemistry and Nutrition, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K.

less remunerative, dual roles of scientific institution and public leisure amenity.

With increasing time for leisure, the number of visits to botanic gardens has, in general, risen, despite the fact that most of them spend little on advertising and promotion. Since most of these gardens charge no entrance fee, the question arises as to whether the benefits derived from free public access to botanic gardens exceed the costs of maintaining them.

The object of this study is not to present an all- embracing economic appraisal of botanic gardens, but rather to assess whether current recreational visitor use values at four selected botanic gardens exceed the financial costs of their maintenance. To achieve this the study employs observed behaviour to make inferences about consumer preferences, and to measure the benefits from public recreational use of the selected gardens. Specifically, a travel-cost model (TCM) is adopted to measure the values people place on botanic gardens. The TCM values non-market goods by identifying how much people, i.e. visitors,

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are prepared to pay to consume (gain access to) environmental goods such as a botanic garden.

Before this approach is implemented, the history and development of the botanic garden in Great Britain is discussed briefly, and there is a short description of the four gardens which form the subject of this study and a summary of their financial costs.

The Development of Botanic Gardens in Britain

The largest group of botanic gardens in Britain are those attached to universities. The first of these to be founded was at Oxford in 1621, while Cambridge established a botanic garden in 1726. Most university botany departments established botanic gardens for the teaching of botany and for research. This tra- dition continued until the establishment of the new universities in the 1960s.

During the nineteenth century botanic gardens were also established in most of the major industrial cities of the country under the auspices of botanic societies (CHADWICK, 1966). A few of these were handed over to local authorities when they were founded and were then opened as public municipal gardens. In general these gardens were only established to dis- play collections of plants and this they continue to do, Some, such as the City Botanic Garden in Sheffield, serve an educational purpose but carry out little research.

In addition to the gardens mentioned above, another important group exists. These are the so-called government gardens, funded as independent insti- tutes by the government, and not through universities or local authorities. These comprise: the Royal Botanic Garden Edinburgh and its outstations at Dawyck, Logan and Benmore; Westonbirt Arbore- tum; Goudhurst; the Royal Botanic Garden Kew and its outstation Wakehurst Place. Of these, by far the best known is Kew, formerly a royal garden, the main function of which came to be the cultivation and distribution of plants which were of great economic importance to the British Empire: tea, coffee, rubber, quinine, and various spices. With the demise of the Empire this role has declined, although Wakehurst Place now maintains gene banks of many of the plants in the world which are threatened with extinction.

Geoforum/Volume 24 Number 2/1993

Botanic gardens were historically important because until relatively recently plants formed a major part of man’s medical treatments. Even in the 1940s doctors and veterinary surgeons still made up their own medicines and many of the ingredients used were of plant origin. However, with advances in physiology and bacteriology, and the development of synthetic drugs, the character of Western medicine radicatly changed and its dependence on plant extracts de- creased. This development was reflected in the teaching of botany, which is no longer taught to undergraduates in most medical schools. Thus, the link between botany departments and medicinal faculties has weakened and botanic gardens have declined in importance.

Even soI most botanic gardens in Britain continue to be associated with university botany departments. However, analysis of university statistics since the mid 1960s reveals a steady decline in both undergrad- uate and postgraduate botany students, both in real terms and as a percentage of the total number of university students. Current university courses in the botanic sciences generally have smaller numbers of students than in the past, and pface a much greater emphasis on biotechnology, microbiology, biochemistry, genetic engineering, and micropropagation. Thus, the function of botanic gardens in university teaching and research has been largely dispiaced by experimental work, and the study of the whole plant has been displaced by studies at organ, cell or sub- cellular level, calling into question the need for many botanic gardens.

site S&&on and Surveys

From the 48 botanic gardens in Britain four gardens were chosen to represent one of each of the different types of botanic gardens in existence: university (Cambridge University Botanic Garden); municipal (Sheffield City Botanic Garden); and two very different types of government garden, the Royal Botanic Garden Edinburgh, with its important research station, and the extensive arboretum at Westonbirt which currently does not carry out any research.

The Royal Botanic Garden Edinburgh has a long history stretching back to 1670 when a Physic Garden was established near Holyrood Palace. The present botanic garden, covering some 25 ha, was planted at

GeoforumNolume 24 Number 211993

Inverleith in 1823, between Edinburgh’s Georgian new town and the port of Keith, In 1889 the garden became entirely funded by the British government, and is currently controlled by the Scottish Office, functioning under the National Heritage (Scotland) Act 1985. The garden has its own research establishment where work is carried out on the taxonomy of the world? flora, with particular emphasis on the tropical and relatively arid south-west zone of Asia; the Sino-Himalayan zone; new world tropics, espe- cially Brazil; and Britain. A horticulture diploma course is taught at the garden, and it houses one of the largest horticulture libraries in the country.

Edinburgh has extensive glasshouses, as well as rock gardens and ponds, and it runs a varied educational programme for schools. The title Royal Botanic Gar- den Edinburgh includes three outstations: the Younger Botanic Garden, Benmore near Dunoon; Logan Botanic Garden near Stranraer; and Dawyck Botanic Garden, Stobo near Peebles, so the total area of the gardens exceeds 100 ha. No admission price is charged for access to the garden in Edinburgh but the number of visitors is carefully monitored: in 1988 it was one of Edinburgh’s major visitor attractions with more than 750,000 visitors (HOUSE OF COM- MONS, 1990).

At 15.6 ha, Cambridge University Botanic Garden is somewhat smaller in scale than Edinburgh. It is financed through Cambridge University and is part of its Department of Botany. Like Edinburgh the garden is centrally situated in the city, but it attracts fewer tourists. It charges no entrance fee, except on Sunday, and there is no detailed monitoring of visitor numbers. A total of 5950 visitors paid an entrance fee on Sundays during the peak period May-August 3988, but that number did not include any of the 2000 Sunday season ticket holders. The Superintendent of the Garden estimated the annual number of visits for all days throughout 3989 to be approximately 45,000.

Westonbirt, near Tetbury in Gloucestershire, was formerly the estate of Robert Stayner Holford who began planting trees and shrubs from around the world in 1826. Gradually, the collection grew in importance and in 1956 the garden was placed in the hands of the Forestry Commission, under whose control it has remained ever since. Westonbirt differs markedly from the other three gardens in the survey

217

in that it is located in a rural area with no large centres of population nearby and has no public bus service. At the rime of the survey in 1990, there was an entrance charge of g1.80 per visit, though a season ticket could be purchased. Because an entry fee is charged, the number of visits each year to the arboretum is accurately known: e.g. 185,400 in 1989. In addition to entry fees, income is also generated by a visitor centre and cafe. No research is currently being carried out at Westonbirt, but the garden contains a nationally important collection of trees.

At 7.6 ha Sheffield City Botanic Garden was the smallest of the four gardens examined by the survey. It is a municipal botanic garden located near to the centre of Sheffield, and was founded by the city council. No research is carried out at Sheffield, but there are programmes of lectures, exhibitions and events for public education throughout the year. No entrance fee is charged and, though there is little monitoring of visitors, the garden administrators estimate that around 50,000 visits are made to the garden each year,

Since the method of valuing botanic gardens was based on visitors’ willingness to pay (WTP) to gain access to the gardens, this required a random sample survey of visitors to be interviewed to ascertain the costs in terms of travel and time which they had incurred in order to visit the gardens. Visitors to Cambridge, Edinburgh and Sheffield were interviewed over a period of 8 days at each site, while at Westonbirt the survey was carried out between April and December 1990 by Forestry Commission staff. All four surveys included some interviews on each day of the week, though the sample at Westonbirt was more fully stratified in order to be representative of the spread of visits throughout the year.

Data on the frequency of visits by each individual, their socio-economic characteristics, preferences and the activities undertaken at the botanic garden were collected, and the number of questionnaires com- pleted at each site comprised: Cambridge 201; Edin- burgh 202; Sheffield 310; and Westonbirt 414.

Financial Costs

In relation to their revenue-generating activities, the financial costs of running botanic gardens and their

fable 1. The financial costs and revenues to botanic gardens in relation to their characteristics

Cambridge Edinburgh Sheffield Westonbirt

Size (ha) Total cost per annum Staff costs as % of total costs Revenue Grant-in-aid Number of visitors

15.6 24.8* 7.6 200 &369,000 f4.476.000 - f406,OOO

81.0 56.9 - 62.0 &101,400 &120,255 - f24.5 ,OOO f267,600 ~4,107,500 - f161,OOO

45,000 750,ooot 50,000 184,000

218 GeoforumNolume 24 Number 2/199<

associated research are substantial. However, it is little over X1.9 million in 1988. This compared to a worth pointing out that, in the context of environ- research budget of around $1.6 million, with the mental protection for some countryside goods such as remaining grant-in-aid spent on maintaining the three nature conservation, subsidies to botanic gardens are outstations. Overall, revenues at Edinburgh for 1988 relatively small. covered less than 3% of the total running costs.

Since many botanic gardens are attached to universities, periodic episodes of retrenchment in this sector from the 197Os, together with a philosophy in government of looking for value for money in public spending and of reducing subsidies, have resulted in considerabIe pressure on botanic gardens. For exampie, the University of Hull has relinquished its botanic garden; the University of Reading has rationalized activities at its gardens and has reduced their number from two to one; while the University of St Andrews has leased its botanic garden to North East Fife District Council. Even outside of the aca- demic sector problems have been experienced: in 1989, for instance, the government sought to reduce funding for Kew Gardens from f8 million to &S million.

Revenues at Cambridge covered a much higher proportion of total costs (27.5%) than was the case at Edinburgh, though most accrued from outside sources, with the gardens receiving 25400 in revenue from Cambridge City Council; f11,950 from the Friends of the Garden; &lO,OOO from Sunday entrance fees, yearly publications, etc. and ~74,~ from endowment interest. Grant-in-aid made up the shortfall between costs and revenues, and, again, part of that figure covered research costs. Westonbirt, the only garden charging a standard entry fee, generated an even greater percentage of its costs from revenue (60.3%) and received the lowest grant-in-aid of the three gardens.

The Individual TCM

The financiat status of the botanic gardens at Cam- bridge, Edinburgh, Sheffield, and Westonbirt is documented in Table 1. Financial details were not available for Sheffield. This was due to a combination of local authority confidentiality concerns (the maintenance of the botanic garden is contracted out to a private firm), and pooling of costs between the botanic garden and other parks in Sheffield.

The travel-cost method assumes that an individual must visit a recreation site to consume its services. Thus, the value of a non-marketed good to an individual can be inferred from the relationship between travel-cost expenditure and recreational visits. Travel cost thus serves as a proxy for prices, with a change in price causing a change in consumption. The travel- cost method models the demand for recreation services over some time.

The Royal .Botanic Garden Edinburgh received a sum of grant-in-aid from its governing body which amounted to 34 times its annual revenue of &120,255. This revenue is partly generated by the public gardens in Edinburgh, which take approximately 47% of the total grant-in-aid to maintain; this amounted to a

Specifically, the individual travel cost method (ITCM) states that IVij, the number of visits made by an individual i to a site j, is a function of a variety of factors including: the cost of travel to gain access to the site, plus any entrance fee; the socio-economic

*Plus an additional 79 ha at the outstations. $Plus an additional 87,000 visits to outstations.


Table 2. Variables available for individual travel-cost model

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Variable Description Variable Description

Nij Visit frequency TCii Travel-cost SSij Substitute site specified (O-l) EN~OYii Enjoyment of visit as % of day’s enjoyment .KiDS, Number of children in party HHij Travel from home or holiday address (O-1) BOTSCI; Respondent trained in botanical science (O-1) PMAGi Buys a plant or gardening mag (O-l)

ZNCi Household income LENij Length of visit Pij Total number in party AGEi Age of respondent PRij First ever visit to site (Cl-l) STKTii Season ticket holder (O-l) HORC Respondent trained in ho~iculture (O-l) PSOCi Member of plant or garden society (O-l)

characteristics of individual i; the attributes of site j in an overestimate of consumer surplus per visit. To terms of the range of attributes or activities available avoid this problem the truncated maximum likeli- at the site and the quality of those activities; and the hood (TML) method was used to model the data price of access to substitute sites. (MADDALA, 1983).

Both sample selection and the type of sampling pro- cedure have significant implications for the esti- mation of consumer surplus. A sample of visitors to a botanic garden j records an individual i as having visited the site Nij times within a specified time, where Nii is a positive integer.

In this study the general model was

N~=f(TCii,SSij,V,,Ci,ei) (2)

where:

Nii = number of visits by individual i to site j in the previous 12 months.

Thus, non-users and those who do not visit within the specified time are excluded from on-site sample surveys of recreational visits to botanic gardens, though information about them is clearly relevant in deter- mining the factors which cause people to visit a garden. Thus, the sample is selected according to the value of the dependent variable, thus violating assumptions about the distribution of the error term in OLS regression.

TC, = travel cost faced by individual i to gain access to site j.

SS, = O-1 variable: whether individual i specified a substitute to site j.

V, = vector of the characteristics of individual i’s Nijth visit to site j.

Ci = vector of the socio-economic characteristics of individual i.

f$ = error term.

In site surveys the respondent’s total number of visits N;j over the time is observed only if N~j 3 1, and is not observed if N:j < 1. Thus, the observed number of visits Nij may be defined as:

The main objective in the survey of visitors was to examine the preferences and behaviour of visitors, and to compare them with their costs to gain access to the gardens. A list of variables used in the model is included as Table 2.

Nii = N$=/$Xij+eij ifN$&l,

0 if N$< 1, (1)

where Xij is a vector of independent variables with coefficient vector pi, and eij is an error term. The sample is truncated and no data exist on either the frequency of visits of the characteristics of individuals who do not choose to visit the botanic garden during the specified time, because no sample of these was drawn. This means that OLS regression will be biased towards positive responses, providing a biased estimate of the true slope of demand function, and hence

For visitors making the journey by car or motor cycle, the travel cost 7’Cij was calculated as the sum of full car running costs per person, plus the time cost of travel for the respondent to and from the site. Car running costs were estimated as SO.35 per mile, a figure which took account of the cost of petrol plus fixed costs such as depreciation, road tax, insurance and service costs. This approach has been adopted in previous travel-cost studies, in one of which a survey confirmed that such estimates of full car running costs are close to the costs which respondents themselves

Table 3. Individual travel-cost method estimates derived from the linear model*

Garden

OLS Truncated-maximum likelihood

Consumer Consumer Travel-cost surplus Travel-cost surplus coefficient (f) coefficient (f)

220 Geoforum/Volume 24 Number 20993

estimate for their trip (WILLIS and GARROD,

1991). Time costs were estimated at the DEPART-

MENT OF TRANSPORT (1987) standard average

values of 43% of earnings. Travel costs for visitors

using public transport were calculated as the sum of

time costs plus a standard public transport fare rate of

SO.35 per mile, while travel costs for visitors on foot

or on cycles were calculated solely on the basis of time

costs. Because time and transport costs were collinear

they were summed to form a single cost variable.

the semi-log (dependent); the semi-log (indepen-

dent); and the linear. Previous ITCM studies of

recreation sites [e.g. WILLIS and GARROD (1991)]

have also investigated these functional forms finding,

in each case, that only the linear specification gener-

ated consumer-surplus estimates which were in any

way acceptable. This study confirmed those findings.

The variable ENJOYii was included in the analysis

because the botanic garden visit may have been only

part of a broader recreational experience, This

broader recreational experience may have included

the enjoyment of the trip to and from the garden, and

any visits to other recreation sites on the way, all of

which would be covered by the same travel cost

estimate used in equation (2). The size of the party,

specified as Pi,, was included as a proxy for the non-

financial organization costs of the visit, while the

variables HORTiy PMAGi, PSOCi and BOTSCIi were included as indicators of a preference for visiting

botanic gardens.

Where these alternative functional forms were esti-

mated, the double-log generated infinite consumer

surplus, while the semi-log (dependent) gave single

visit consumer-surplus estimates in excess of those

which might be considered reasonable, e.g. Edin-

burgh g37.91 and Cambridge f15.35. The semi-log

(independent) form which has often been rejected on

the grounds that it often suffers from heteroskedastis-

tic disturbances, gave results which implied that con-

sumer surplus at all sites was negligible.

TCM Results

The TML method was used to fit ITCM models to the

data from each site. Because the purpose of this study

was to estimate the recreational benefits for visitors to

each site, the prime consideration in the choice of

each model was its ability to generate a reasonable

estimate of consumer surplus. For each model, four

functional forms were investigated: the double-log;

Rejecting the possibility of negligible consumer sur-

plus being generated by visitors to each site left the

linear form. While this form has certain problems,

particularly when it comes to the aggregation of

results, it generally gives reasonable single-visit

consumer-surplus estimates. The ITCM linear model

estimates for each botanic garden are shown in Table

3, with estimates based on OLS again included for

comparison. Only the travel-cost coefficient for Shef-

field was not statistically significant at any meaningful

level: the Cambridge travel-cost coefficient was sig-

nificant at the 1% significance level; while the coef-

ficients for Edinburgh and Westonbirt were both

significant at the 16% level, which indicates only a

fairly low level of statistical significance. The associ-

ated estimates of consumer surplus ranged from

Edinburgh

Sheffield

Cambridge

Westonbirt

-0.1576 (-1.07)

-0.1017 (-0.40)

-0.3574 (-2.92)

-0.3045 (-1.48)

3.17 -0.5501 0.91 (-1.40)

4.92 -0.2232 2.24 (-0.11)

1.40 - 1.4456 0.35 (-3.03)

1.64 -1.9470 0.26 (-1.59)

*t-Statistics in parentheses.

GeoforumNolume 24 Number 20993 221

approximately go.26 at Westonbirt, to f2.24 at Shef- field. These figures were interpreted as the welfare benefit gained from each visitor’s first visit of the year to a specific garden, and did not take into account the benefits derived from any subsequent visits.

Table 4. Willingness to pay to gain access to a garden

A simple robustness analysis was carried out for the ITCM estimates at each site. In this analysis the coefficients of the travel-cost variables were compared when all other significant variables in the model were left out in turn. This process gave some idea of the magnitude of the errors which might occur if any important explanatory variables had been omitted from the model. As well as being highly sensitive to the specification of functional form, the travel-cost coefficient was also sensitive to variable selection [see GARROD er al. (1991) for details]. Nevertheless, the linear functional form was the only one which pro- duced consumer-surplus estimates comparable with those from other non-priced recreational studies, and from known admission prices to similar facilities such as those National Trust properties which are renowned for their gardens. Note too that estimated consumer surplus was lowest at Westonbirt, which is consistent given that this was the only garden where a regular admission price (f1.80) was charged: Cam- bridge made a small charge for entry at weekends.

Garden

Edinburgh Sheffield Cambridge Westonbirt*

Willing Realistic to Pay entry

entry fee fee Standard (%) (mean f) deviation

93.0 0.769 0.693 72.6 0.499 0.313 87.8 0.677 0.536

100.0 1.800 -

*Westonbirt charges a standard entrance fee of f1.80 to visitors. This charge is lower for children, senior citizens and season ticket holders.

comparison to be made between the mean suggested entry fees, the actual entry fee charged at Westonbirt and the ITCM consumer-surplus estimates for a single visit.

In addition to questions about visitor behaviour and preferences, the surveys at Sheffield, Cambridge and Edinburgh also asked visitors whether they would be willing to pay an entry fee to gain access to the gardens. In each case a large majority of respondents said that they would be willing to pay such a fee, and these were then asked what they would consider to be a realistic charge to gain entry. Questions similar to these form an important element of the contingent valuation technique (CVT), which is often used in recreation demand surveys in order to elicit some measure of respondents~ willingness to pay to use, or to gain access to, a site. Surveys utilizing this technique must be carefully designed in order to eliminate a number of biases which may influence the accuracy of any WTP measures [see GARROD and WILLIS (1990)]. Again, however, the questionnaire survey was not intended to form the basis of a major CVT study and the entry fee question was only intended to give an indication of the size of charge that could be made at each garden without unduly affecting visitor numbers. Even so, its inclusion allowed an interesting

The mean values for the suggested charge per visit for those visitors who responded positively are shown in Table 4, and range from approximately X0.50 at Sheffield to go.77 at Edinburgh. While these estimates were considerably lower than the &I. .80 charge already levied at Westonbirt, they were, in the cases of Edinburgh and Cambridge, not dissimilar to the ITCM estimates. Unfortunately, the design of the survey provided no means of establishing the validity of the WTP estimates and did not preclude the presence of potentially damaging biases, implying that any comparison between WTP and other benefit estimates must be approached with caution.

Aggregation

It has often been argued that the actual functional relationship between individual visits and travel cost is non-linear, and possibly convex. If this were so, and a convex functional form provided a better fit of the data than the linear, then WILLIS and GARROD (1991) have shown that the single-visit estimates shown in Table 3 are lower-bound estimates of consumer surplus per visitor, per year. Using this result, and given the assumption that the underlying functional form was indeed convex, the single visit consumer-surplus estimates generated in this study can be used to calculate aggregate lower-bound figures for the yearly consumer surplus generated by the visitors to each garden.

222 GeoforumNolume 24 Number 2/1993

Table 5. Aggregate lower-bound yearly consumer-surplus estimates*

Garden

Consumer surplus Total

Mean per single consumer Visits per visits Visitors visit surplus

year per head per year (2) (f)

Edinburgh 750,000 20.27 37,000 0.91 33,700 Sheffield 50,000 29.27 1700 2.24 3800 Cambridge 45,000 15.41 2900 0.35 1000 Westonbirt 185,400 14.90 12,400 0.26 3200

*Figures for estimated visitors per year and total consumer surplus are rounded to the nearest 100.

Total yearly visits varied from approximately 750,000 per year at Edinburgh down to around 45,000 per year at Cambridge. Dividing these by the mean number of visits per individual as observed in the sample survey gave an estimate of the total yearly number of visitors to each garden (see Table 5). Estimates of mean annual visits for individuals, as calculated from the samples, were rather higher than expected, but this could be accounted for in the city gardens by the large proportion of local people visiting regularly, and at Westonbirt by the activities of season-ticket holders. In the absence of more detailed overall visitor profiles for each garden, more representative weighted estimates of mean annual visits per head could not be calculated. Multiplying the above figures by the estimated consumer surplus for a single visit gave lower-bound aggregate consumer-su~lus estimates which ranged from just over &loo0 at Cam- bridge to around f33,OOO at Edinburgh (see Table 5). Recall that Cambridge has an entry charge at weekends, so this is consumer surplus above priced admission, and also comparatively few visits (45,000) during the year.

However, these figures were based only on the benefits derived by each visitor from their first visit of the year, and represent the very lowest possible estimates of the recreational benefits which were derived from each garden. Most visitors make more than one visit in a year, and a clearer idea of the magnitude of overall recreational benefits would be gained if some upper-bound estimate could be derived. The assumption of a convex functional form, as well as conven- tional economic theory, suggested that each marginal visit after the first was likely to provide a benefit less than, or equal to, that derived from the first visit. Thus, estimating the aggregate benefit of each mar-

ginal visit as equivalent to that of the first visit, gave a reasonable idea of the magnitude of the upper bound of the total recreational benefit: however, the actual upper bound may be higher because an underlying convex functional form implies an underestimate of benefit for respondents making only a single yearly visit to a garden [see WILLIS and GARROD (1991)J. These upper estimates of the aggregate total recreational benefits of botanic gardens were &682,500 at Edinburgh, &112,000 at Sheffield and f15,780 at Cambridge.

A different estimate of aggregate recreational benefits was obtained from examining the aggregate estimates of WTP derived from multiplying the hypo- thetical per visit entry fees shown in Table 4 by the total estimated yearly number of visits to each site. Table 6 details these aggregates, which ranged from f569,833 at Edinburgh to f30,479 at Cambridge and f24,941 at Sheffield. It must again be emphasized that these estimates were based on data from a survey which was not designed as a vehicle for the contingent valuation method, and that the possibility of biases meant that these aggregate estimates could not be

Table 6. Aggregate yearly willingness to pay (WTP) based on contingent valuation questions*

Garden

Edinburgh Sheffield Cambridge

Visits per year

750,000 50,000 45,000

Entry charge

per visit (f)

0.760 0.499 0.677

Total WTP

(X)

570,000 25,000 30,500

*Figures for estimated total WTP are rounded to the nearest 100.

GeoforumNolume 24 Number 2/1993

usefully compared with the aggregate estimates of benefit derived from the ITCM.

Conclusions

Comparing both sets of estimates with the total grant- in-aid shown in Table 1 for Cambridge, Edinburgh and Westonbirt showed that neither the ITCM nor the CVT estimates of the net welfare benefits from recreation exceeded the grants which made up the difference between operating costs and revenues at these sites. In fact none of the benefit measures generated in this paper could be shown to offset more than a small proportion of the total grant-in-aid made to each botanic garden.

The ITCM estimates, in particular, fell far short of this target. These estimates, which were based on data which were not ideal, were dependent on the specification of both variables and functional form. Better data may have improved the reliability of the ITCM model and the robustness of its estimates, though the aggregation problems inherent in the preferred linear model make it no more than a useful indicator of the lower limits of total recreational benefits.

For an estimate of total benefits, contingent valuation techniques may be used. No model was developed to validate the CVT results as suggested by MITCHELL and CARSON (1989), and it is possible that the benefit estimates given in Table 6 may be subject to certain biases. Even so, they provide an estimate of the total aggregate recreational value of the gardens which may be set alongside the lower-bound values given by the ITCM model. A more in-depth CVT study would give an improved idea of these recreational benefits; however, such an undertaking would be costly and would be difficult to justify for gardens already under severe financial constraints.

In order to completely offset the current levels of grant aid at Edinburgh and Cambridge, a future CVT study would, based on current levels of visiting, have to generate estimates of over f5 per visit at both sites. This sum would cover both the costs of maintaining the garden and the costs incurred by the research establishments at each institution. Consequently, a somewhat lower figure would cover the upkeep of the

223

garden, leaving that proportion of grant aid spent on research to be justified in other ways. This approach would have a great effect at Edinburgh where a figure of approximately f2.60 per visit would cover all non- research-generated costs. However, the recreational, or use, values form only part of the total economic value of each garden, the other elements of which are the so-called non-use values which take into account the public’s valuation of a particular site, regardless of whether they visit it or not.

Such non-use values include individuals’ valuations of their option to visit the site at some time in the future (option value); their valuations of the knowledge that the site continues to exist (existence value); and their valuations of the site as an asset for future generations (bequest value). The perception of botanic gardens as havens of biological diversity and as a valuable gene pool, coupled with their worth as a resource for education and scientific research, may mean that these values, particularly the existence and bequest values, could prove to be substantial. Unfortunately, no estimates of these values at present exist, and a wide-ranging sample survey of the general public would be needed to obtain them: this was beyond the scope of this study. However, if such a survey were to be carried out it is quite possible that the estimated non-use values would equal or even exceed the recreational use values, thus closing the gap between the running costs of these botanic gardens and their estimated benefits. This conjecture can be supported by the evidence of a number of studies looking into both use and non-use values [e.g. WILLIS (1990) and WALSH et al. (1984)] and by the fact that those sections of the population which do not visit the gardens are many times larger than those sections which do.

Costs documented in this study are financial costs, rather than opportunity or resource costs against which welfare benefits should be compared. In the absence of a full cost-benefit analysis it is not clear whether resource costs are greater or less than financial costs. The shadow price of labour may in the short run be less than the financial wage rate, because of above-average unemployment in both the Edin- burgh and the Sheffield labour market areas. On the other hand, the capital value of the land was not included in the financial costs, and the Cambridge,

224

Edinburgh and Sheffield gardens would all offer

prime city centre development sites.

Clearly then, this study does not tell the whole story

of the benefits to be derived from botanic gardens,

either from their use for recreation and other pur-

poses or from their continued existence. With more

time for leisure, and an increasing interest in green

pursuits, the number of visits to these gardens is likely

to rise, making it probable that public open access

recreation will have a greater part to play in offsetting

future grant aid. Furthermore, with the growing con-

cern over the loss of a great many plant species all

over the world, botanic gardens may yet find a more

important r61e in scientific research, possibly as a

location for important exsitu conservation projects or

as essential gene banks.

Ack~iuwiedgeme~ts - We gratefully acknowledge the assistance of John Main the Curator of the Royal Botanic Garden Edinburgh in disaggregating financial costs between the botanic garden in Edinburgh and its outstations and research activities, Research for this paper was supported by the E.S.R.C. under the Countryside Change Initiative (Award No. W104251008). The views expressed in this paper are those of the authors alone and all errors and omissions remain our own.

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The economic value of botanic gardens: a recreational perspective