Proceedings of Applied International Business Conference 2008
ECOTOURISM DEMAND: A REVIEW OF CURRENT ECOTOURISTS MARKET
Zaiton Samdin ψand Mohd Rusli Yacob
Universiti Putra Malaysia, Malaysia
______________________________________________________________________________________
Abstract
Ecotourism is becoming one of the most important and growing sectors in many developing countries. This
is especially so in tropical regions and those countries which have been blessed with a great diversity of
flora and fauna including Malaysia. This industry has been growing rapidly for the past two decades and is
expected to grow further in the future. This paper will identify market characteristics of ecotourists which
include profiles and characteristics of visits. The foundation of ecotourism demand are based on set of
human characteristics namely gender, age, education, income, values, and experiences etc. These
characteristics have some potential implications in ecotourism development. The information will be
useful, not only for management and planning purposes but also for the marketing strategies in particular.
Therefore, it is essential to understand the potential effects of the expanding ecotourism sector, so as to
identify management priorities for the present and potential ecotourist destinations. Poorly planned and
managed ecotourism may damage the same wildlife and natural or cultural resources.
______________________________________________________________________________________
Keywords: Ecotourism; Sustainable tourism; National park; Protected areas.
JEL Classification Codes: Q2; Q26; Q32; M31.
1. Introduction
Ecotourism involves visiting undisturbed natural areas and promotes conservation, encourages low visitor
impact and creates the socio-economic involvement of the local population. Agrusa and Guidry (2006)
assert that ecotourism is becoming one of the most important sectors, and is growing in many developing
countries. This industry has been growing rapidly for the past two decades and is expected to grow further
in the future. Today, for developing countries, ecotourism is becoming an option for generating more
income from the tourism sector. In 1997, the WTO announced at the World Ecotour Conference that
‘ecotourism is worth US $20 billion a year’. Due to the development and importance of ecotourism, the
United Nations (UN) declared 2002 the ‘International Year of Ecotourism’.
Ecotourism in Malaysia has been important since 1994. It started when the Tourism Malaysia realized the
extent of the growth of this type of tourism (Ministry of Culture, Arts and Tourism [MOCAT], 1996). The
Ecotourism in Malaysia is the fastest growing form of tourism, and MOSTE (1998) estimated that 481,900
foreign tourists were involved in ecotourist activities throughout Malaysia in 1994, 6.7 % of all tourist
arrivals (7,231,000). Most of them were interested in the biological richness of Malaysia’s tropical forests,
marine ecosystems and wetland ecosystems (MOSTE, 1998). In addition, it was estimated that 7-10 % of
the total number of tourists were ecotourists or nature-based tourists, and that they were visiting natural
areas such as national parks, state parks and marine parks. Studies on the travel behaviour of the
international tourists found that they travelled more extensively in peripheral regions (Oppermann, 1992)
and most of the national parks and reserve areas in Malaysia are located in such regions. Since 1994, the
Malaysian Tourism Promotion Board (MPTB) has used elements of nature in its marketing and
promotional strategy. The slogan used was ‘Naturally more’.
Furthermore, the major tourist attractions in Malaysia are diverse in their natural attractions such as virgin
rain forests, mountains, coastlines and islands. According to Hashim (1998) statistics indicate that the
ψ
Corresponding author. Zaiton Samdin. Department of Hospitality and Recreation, Faculty of Economics
and Management, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia. Corresponding author
Email: [email protected]
Proceedings of Applied International Business Conference 2008
fastest growth in tourism in Malaysia is in nature-based activities (World Travel and Tourism Council
[WTTC], 2002). The tourism industry in Malaysia is highly dependent on natural resources as its major
attraction. Malaysia has 54 protected areas, or about 4.5% of the land surface of the country, totalling
1,483,000 ha. There are 19 national parks in the country and Taman Negara National Park (TNNP) is
widely known. Others include Endau Rompin, Kinabalu, Mulu and Niah. There are numerous nature-based
activities on offer at these national parks, including hiking, bird-watching and camping (Ghazali, 2000).
Besides that, there is a strong and growing interest in ecotourism destinations especially in ecotourism
destinations especially in the national parks and protected areas. This paper will discuss the demand for
ecotourism market. Understanding eco-tourists’ profiles and trends such as travel pattern, motivation and
expectation are essential in order to develop an effective marketing strategies and sustainable industry.
2. Ecotourism: A Definition
Nature-based tourism, which encompasses adventure tourism, ecotourism, alternative tourism, educational
tourism and sustainable tourism, is one of the most exciting sectors in the tourism industry. All these terms
are used synonymously and this leads to confusion (Weaver, 2001). In the early literature, such as that of
Boo (1990) states that ecotourism is indistinguishable from ‘nature-based’, ‘nature-oriented’ or ‘nature’
tourism. In its time ecotourism has also been called ‘nature tourism’, ‘green tourism’, ‘natural history
tourism’, ‘rural tourism’ and ‘adventure tourism’ (Honey, 1999). The main problem which arises is that the
definition of ecotourism overlaps other types of nature-based tourism. In other words, there is little or no
differentiation made between ecotourism and nature-based tourism.
Cater (1994) maintains that the term ecotourism is surrounded by confusion. Valentine (1993) and Western
(1993) point out that nature tourism and ecotourism share the same meaning, but both of them attempt to
make a clear distinction between the two terms. Nature-based tourism is defined as ecologically sustainable
tourism, with the primary focus on experiencing natural areas. Ecotourism is defined as ecologically
sustainable tourism, with the primary focus on experiencing natural areas that foster the environment and
cultural understanding, appreciation and conservation. The original definition of ecotourism was provided
by Ceballos-Lascurain in 1987:
… travelling to relatively undisturbed or uncontaminated natural areas
with the specific objective of studying, admiring, and enjoying the scenery
and its wild plants and animals, as well as any existing cultural
manifestations (both past and present) found in these areas (p. 14).
Following Ceballos-Lascurain’s definition, some researchers have come up with their own definition of the
concept. We can see that they have added several elements such as conservation, education and
sustainability. As an example, the Ecotourism Association of Australia (1992) defined ecotourism as
‘ecologically sustainable tourism that fosters environmental and cultural understanding, appreciation and
conservation’. The Ecotourism Society defines ecotourism as ‘responsible travel to natural areas that
conserves the environment and improves the welfare of local people’ (Western 1993:8).
Malaysia has adopted International Union for Conservation of Nature (IUCN) definition of ecotourism.
This, it says, is:
environmentally responsible travel and visitation to relatively undisturbed natural
areas, in order to enjoy and appreciate nature (and any accompanying features both past and present), that promotes conservation, has low visitor impact and
provides the beneficially active socio-economic involvement of local populations.
(Ceballos-Lascurain [1996]).
This definition emphasises five main aspects. These are: (1) low impact on the environment and on local
culture; (2) covering nature as well as culture; (3) preventing damage as far as possible; (4) repairing
whatever damage is unavoidable; and (5) benefiting the people of the area.
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3. Market of Ecotourism
Lindberg et al. (1981) found that ecotourism had recorded faster growth than the tourist industry as a
whole. Ecotourism is one of the fastest growing sectors compared to other types of tourism (Eagles, 1995).
It is estimated as growing at 10-15% annually. The Canadian Wildlife Service states that over US$200
billion was spent on ‘ecotourism activities’ worldwide in 1990. This section will discuss the market
characteristics of ecotourism which will cover profile and characteristics of visits of eco-tourists.
(a) Profile of Eco-tourist
Individual varies in their response to travel and participated to ecotourism destination. Most of the previous
studies in ecotourism present the significance differences in eco-tourists profile towards ecotourism
demand. The common eco-tourists’ profiles are age, education, income, ethnicity and gender. According to
WTO (2001a), most eco-tourists are in a high social bracket, at a high educational level and are aged more
than 35; there are also more women than men. In Germany, the current demand for ecotourism is estimated
at between 1 and 3 million (WTO, 2001b); most of them are in their forties, educated and have an income
of between Eur. 1,500 and Eur. 2,500 per month. This section will discuss the profile of eco-tourists; the
socio-demographic and economic characteristics are obtained from the selected empirical studies.
Gender
Generally, male are more likely to participate in the most of ecotourism destination or outdoor recreation
activities. In particular, men are more likely than women to participate in ecotourism activitiesconsumptive activities such as mountain climbing, fishing etc and in physically strenuous activities such as
kayaking, water rafting, canoeing etc. Meanwhile, participation in common ecotourism activities with less
strenuous ecotourism activities such as swimming, picnicking, walking and sightseeing significantly shows
more female than male. Previous studies have found that ecotourism is dominated by male visitors. Studies
that were conducted by Ahmad et al. (1992) in TNNP found that 58% of visitors are male. Zaiton (2007)
has similar findings; the majority of the visitors (60%) to TNNP were male. Mohd Rusli (2006) studies in
Redang Island Marine Park (RIMP) found that 63% of visitors were male. Eagles and Cascagnette (1995)
discovered that Canadian ecotourists were equally distributed in gender. On the other hand, Blamey and
Hatch (1998) showed that 55 % of ecotourists in Australia were female.
Age
Next is age. Age is the most important socio-economic profile of participation in ecotourism destination.
Normally, age indicates the inverse relationship with the participation and involvement in ecotourism
activities; an increase in age results in a decrease in participation in ecotourism activities. Diamantis
(1998) found that two-thirds of UK eco-tourists were in the age category between 25 and 54 (in Wight,
2001). Zaiton (2007) found that most of the visitors to TNNP were in the age bracket 26-35. This is
followed by the category 18-25 and 36-45. This result is supported by studies by Lindberg et al. (1998)
where it was discovered that most of the visitors (89.0 %) to TNNP were in the age group below than 40
years olds. According to Chin et al., 2000, 76.0% of visitors to Bako National Park were aged between 16
and 40 years olds. Mohd Rusli (2006) found that the mean age of visitors to RIMP was 34; it might be
possible to say that the age group of the majority of visitors is between 30 and 40 years old. All of these
findings suggest that the younger generations have a greater intention of visiting the tropical rain forests
and national parks.
Education level
Generally, education is positively related to the participation in ecotourism destination or activities.
Diamantis (1998) discovered that 46% of UK occasional ecotourists attained a first degree, 22% had a
secondary education and 21% were postgraduates (in Wight, 2001). According to Eagles and Cascagnette
(1995), more than 64% of Canadian ecotourists had completed their university education and 24% had
received a post-secondary education. Zaiton (2007) discovered that majority of visitors (26.7%) to TNNP
had first degrees and 23.9% had Masters/PhD qualifications respectively. Pau (1993) and Khoo (1995)
reported similar finding; most visitors to TNNP are university educated.
Occupation
The participation in ecotourism destination or activities by people engaged in different occupations is
related to availability of their leisure time, income and age. Normally, students (over 18 years old of age)
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Proceedings of Applied International Business Conference 2008
are more likely to participate in adventure ecotourism activities than other adults such as mountain
climbing and water rafting. Retired persons are least likely to participate in ecotourism activities followed
by those unemployment people. Those with managerial and professional occupations are more likely to
participate than farmers.
The Travel Industry Association of America (TIAA, 1994) learned that 35% of eco-tourists in the USA
were in the professional/managerial occupation group. The second highest group was the blue collar
occupations (14%). Similar findings were also recorded for Australian eco-tourists (Blamey and Hatch,
1998). Most visitors of TNNP were professionals (30.0%), such as teachers and doctors. These were
followed by skilled non-manual (18.9%) and skilled manual (17.2%) (Zaiton, 2007).
Income
Blamey (1995) also found that ec-otourists earned more than non-ecotourists. Blamey and Hatch (1998)
agreed that most eco-tourists in Australia earn a higher income than their non-eco counterparts. Backman
and Potts (1993) discovered that eco-tourists earn a higher income than other travellers. Table 1 shows the
summary of eco-tourists profile based on selected empirical studies in Malaysia. It shows that people who
were interested in ecotourism activities were younger generation and in the below 40 age category. In terms
of education level, the majority of eco-tourists were university graduates. Most of the eco-tourists fell into
the professional group and earned high income.
Table 1 Example of Ecotourists Profile Based on Selected Empirical Studied in Ecotourism Sitesa
Gender
Age
Education
Occupation
Income
(years old)
Level
Taman Negara
Male
26-35
University
Professionals
Lower than
National Park1
(60%)
(41.7%)
degree
(30%)
US$1000
(26.7%)
(52.8%)
Redang Island Marine
Male
Mean
University
Full time
RM 3001Parks2
(63.1%)
(34.1%)
Degree
employment
RM6001
(45.6%)
(66.1%)
(37.3%)
Putrajaya
21-30
College and
Government
RM1001Wetland Park3
Male
(67%)
University
sector
2001
(52%)
(80%)
(51%)
(57.5%)
Payar Island Marine
21-30
University
Private Sector
RM1001Park4
Male
(42.3%)
degree
(60.9%)
RM2001
(58.1%)
(46.0%)
(39.5%)
Note;
a
The percentage are based on the highest score
1
Zaiton, S. (2007)
2
Mohd Rusli, Y. , Willis, K. and Alias, R. (2006)
3
Alias, R. and Juwaidah, S. (2005)
4
Mohd Rusli Y., Ahmad S., Alias R., and Khairil W (2007).
(b) Characteristics of Visit
This section will discuss the characteristics of visit of the ecotourists. Three characteristics will be
discussed; reasons for visiting, activities and trip length.
Reasons for Visiting
Diamantis (1998, in Wight, 2001) discover that reasons for visiting was dominated by ‘to experience new
and different life styles’, followed by ‘to explore the area and be educated’ or ‘to increase knowledge’. On
the other hand, Blamey and Hatch (1998), found that Australian nature-based tourists were highly
motivated by the natural beauty of the sites, by the wish to have new experiences and for the wildlife.
Goodwin et al. (1997) found that in Zimbabwe wildlife was the main foreign motivation (66%). Canadian
ecotourists’ reasons were dominated by the wish to see the wilderness or undisturbed nature (Eagles, 1992).
Wight (1996) identified a difference in motivations between ecotourists and mass travellers. Ecotourists
were motivated by: (1) uncrowded locations; (2) remote, wilderness areas; (3) learning about wildlife and
nature; (4) learning about natives and culture; (5) community benefits; (6) viewing plants and animals; and
(7) physical challenges. On the other hand, Eagles (1992) listed several motivations of ecotourists on
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Proceedings of Applied International Business Conference 2008
group tours: wilderness and undisturbed nature; lakes and streams; being physically active; mountains;
national or provincial parks; experiencing new lifestyles; rural areas; being beside the ocean; and meeting
people with similar interests.
Activities
Eco-tourists enjoy a wide variety of activities such as life-enriching experiences related to nature,
adventure and culture. According to DWNP (1994) the majority of visitors (76.0%) to TNNP undertook
jungle trekking, and only 2.0% carried out fishing activities. In addition, Lindberg et al. (1998) reported
that the most popular activity at TNNP was hiking. Chin et al. (2000) found that the most common
activities at Bako National Park were hiking (76.0%) sightseeing (72.0%) and observing wildlife (66.0%).
The three activities which dominated for visitors at TNNP were the canopy walkway (77.8%) sightseeing
(65.6%) and jungle trekking (65.5%) (Zaiton, 2007). River exploration and wildlife/bird-watching were
also important.
Trip length
For the length of trip for visitors to the national park, it depends on their activities in the park. Much of the
research found that eco-tourists stay longer than general tourists. As an example, research by Blamey and
Hatch (1998) found that nature-based visitors tended to spend a longer time on their visit. Studies by
DWNP (1995) found that the length of stay at TNNP ranged from 2 to 7 days. The average number of days
was 3. Local visitors tended to stay for a shorter period than international visitors, a finding similar to that
of Good (1998) in Bako National Park. Day trippers were dominated by local visitors (40%); these visitors
stayed less than 24 hours in the park.
4. Conclusion
Ecotourism is growing in many parts of the world. The foundation of ecotourism demand should be based
on a set of human characteristics which include; gender, age, education, income, values, experience etc.
The eco-tourist socio-demographic and economic profile has some potential implications in ecotourism
development. That kind of information is very useful, not only for management and planning purposes but
also in particular for the marketing strategies, especially for the ecotourism operators. Moreover, studies
previews that eco-tourists earned higher income, educated, more matured and more environmentally
focused compared to other types of tourist. This kind of information is useful especially regarding the
information provided, the quality of service provided and the level of satisfaction. Normally, higher
educated people have better gross monthly income and demand more information and knowledge about the
environment. Thus, this group normally expects a high quality of services provided and they might assume
they would get a better experience from their participation. In addition, Zaiton (2007) found that majority
of the visitors to TNNP were in the age bracket 26-35 years old. The information suggests the park
manager or ecotourism operators should have an effective plan that could concentrate on a particular age
range, like a particular activity for example; this could maximise the utilization of their limited resources.
The information on eco-tourist characteristics of visit also is very important for the ecotourism operators in
their planning and marketing strategies. The common information of eco-tourist characteristic of visit
includes the purpose of visit, times of visits, their origin, duration of stay etc. If the eco-tourist visits
characteristic show a majority had visited the ecotourism destination previously for example, it implies that
there are elements in the park that are interesting to them that make them want to visit again and possibly
come again in future. Possibly the main reason that encouraged eco-tourist to return to the park is the
anticipation of specific activities. Such information is very important for the ecotourism operators and
ecotourism planners for them to market their products and develop their marketing strategies. In fact by
knowing this kind of information the ecotourism operators can reduce their expenditure by focusing their
promotion more specifically to target the selected groups only. In that way, they can reduce their
expenditure for promotion and marketing.
References
Adventure Travel Society, Inc. (1998) Adventure Travel Society Information Packet. The Adventure Travel
Society. New Jersey : Englewood Cliffs.
Agrusa, J.F. and Guidry, J. (2006) Ecotourism and Sustainable Development of the Maya Rain Forest in
Central
America.
[Online,
available
at
243
Proceedings of Applied International Business Conference 2008
http://www.hotelonline.com/Trends/PanAmerProceedingsMay99/EcotourismMaya.html, accesed
on October 28, 2006.
Ahmad S., Wan Sabri, W. M., Abdullah, M. and Zahid, E. (1992) The Local Economic Impacts of the
Development of Taman Negara Malaysia (Report No. 2): Faculty of Forestry, Universiti Pertanian
Malaysia, 71 pp. + Appendices.
Alias, R. and Juwaidah, S. (2005) Use of Dichotomous Choice Contigent Valuation Method to Value the
Putrajaya Wetland Park. Proceedings of the Towards a Richer Understanding of Economy and
Financial Markets-Statistical and Econometrics Advance. , Kota Kinabalu, Labuan International
Campus, 483-489.
Backman, K. F., and Potts, T. D. (1993) Profiling nature-based travelers: Southeastern market segments.
South Carolina: Strom Thurmond Institute.
Blamey, R. (1995) The nature of ecotourism. Occasional Paper Number 21. Canberra: Bureau of Tourism
Research.
Blamey, R., and Hatch, D. (1998) Profiles and motivations of nature-based tourists visiting Australia.
Occasional Paper No. 25. Canberra: Bureau of Tourism Research.
Boo, E. (1990) Ecotourism: The potentials and pitfalls. Washington, DC: World Wildlife Fund.
Ceballos-Lascurain, H. (1996) Tourism, Ecotourism and Protected Areas. Gland, Switzerland: World
Conservation Union.
Chin, C. L. M., Moore, S. A., Wallington, T. J., and Dowling, R. K. (2000). Ecotourism in Bako National
Park, Borneo: Visitors' perspectives on environment impacts and their management. Journal of
Sustainable Tourism, 8, 1, 20-35.
Cresswell, C., and Maclaren, F. (2000) Tourism and national parks in emerging tourism countries. In R.W.
Butler and S. W. Boyd (Eds.), Tourism and national parks: issues and implications (283-299).
Chichester: Wiley.
Diamantis D. (1999) The characteristics of UK’s ecotourists. Tourism Recreation Research, 24, 2, 99-102.
DWNP. (1994) Taman Negara Report 1993. Kuala Lumpur: Department of Wildlife and National Parks.
DWNP. (1995) Taman Negara Report 1994. Kuala Lumpur: Department of Wildlife and National Parks.
Eagles, P. (1992) The travel motivations of Canadian ecotourists. Journal of Travel Research, 31, 2, 3-7.
Eagles, P. F. J., and Cascagnette, J. W. (1995) Canadian ecotourists: who are they? Tourism Recreation
Research, 20, 1, 22-28.
Ecotourism Society (1998) Ecotourism Statistical Fact Sheet: General Tourism Statistics. Washington DC:
Ecotourism Society.
EPU (2001) Eight Malaysia Plan 2001-2005. Kuala Lumpur: Economic Planning Unit.
Filion, F. L., Foley, J. P., and Jacquemot, A. J. (1994) The economics of global tourism. In M. Munasignhe
and J. McNeely (Eds.), Protected area economics and policy: linking conservation and
sustainable development (234-254). Washington DC: World Bank.
Ghazali, M. (2000) Tourism in Malaysia. In C. M. Hall and S. Page (Eds.), Tourism in South and Southeast
Asia: Issues and cases. Oxford: Butterworth Heinemann.
Good, L. (1998) Bako National Park: A Management Plan. Kuching, Sarawak: Forest Department.
Hassan, S. S. (2000) Determinants of market competitiveness in an environmentally sustainable tourism
industry. Journal of Travel Research, 38 (February), 239-245.
Hawkins, D. E. and Lamoureux, K. (2001). Global growth and magnitude of ecotourism. In D. B. Weaver
(Ed.), The encyclopaedia of ecotourism (63-72). Oxon, UK: Cabi Publishing.
Khoo, A. (1995) A study of visitors to Taman Negara. Kuala Lumpur: DWNP.
Laarman, J. G., and Gregersen, H. M. (1996) Pricing policy in nature-based tourism. Tourism Management,
17, 247-254.
Lindberg, K., Furze, B., Staff, M., and Black, R. (1998) Ecotourism in the Asia-Pacific Region: Issues and
outlook. Rome: United Nations Food and Agriculture Organization.
MOCAT. (1996) National Ecotourism Plan. Kuala Lumpur: Ministry of Culture, Arts and Tourism
Malaysia, 303.
Mohd Rusli Y., Willis, K. and Alias R. (2006) Valuing Ecotourism Development in Marine Parks,
Malaysia: A Choice Modelling Approach. Proceedings of the 2nd International Borneo Business
Conference, Kuching, Sarawak, 526-539
Mohd Rusli Y., Ahmad S., Alias R., and Khairil W (2007) Estimation the Conservation Value in Redang
Island Marine parks: A Contingent Valuation Approach. Paper presented at Seminar Faculty of
244
Proceedings of Applied International Business Conference 2008
Economics and Management at Swiss Garden Damai Laut Resort, Lumut, Perak. 04/12/200706/12/2007
MOSTE. (1997) Assessment of biological diversity in Malaysia. Malaysia: Country study on biological
diversity. Kuala Lumpur: Ministry of Science, Technology and the Environment.
MOSTE. (1998) Assessment of biological diversity in Malaysia: Country study of biological diversity.
Kuala Lumpur: Ministry of Science, Technology and the Environment.
Oppermann, M. (1992) Intra-national tourist flows in Malaysia. Annals of Tourism Research, 19, 482-500.
Pau, G. M. (1993) Pre and post visit perceptions on Taman Negara. Faculty of Forestry, Universiti
Pertanian Malaysia, 96.
The International Ecotourism Society (2005) Ecotourism Fact Sheet. [Online, available at
http://www.ecotourism.org/webmodules/webarticlesnet/templates/eco_template.aspx?articleid=15
andzoneid=2., accessed on June 11, 2006]
UNEP (1994) Ecotourism in the Wider Caribbean Region: An Assessment (Technical Report No. 31).
Kingston: Caribbean Environment Programme Technical.
Western, D. (1993) Defining ecotourism. In K. Lindberg and D. E. Hawkins (Eds.), Ecotourism: A guide
for planners and managers , 7-11. Vermont: The Ecotourism Society.
Wight, P. A. (2001) Ecotourists: Not a homogeneous market segment. In D. B. Weaver (Ed.), The
encyclopedia of ecotourism , 37-61. Oxon, UK: Cabi Publishing.
WTO (1998) Ecotourism: In: WTO News, Jan/Feb, Issue 1. Madrid: World Tourism Organization.
WTO (2001a) The British Ecotourism Market. Madrid: World Tourism Organisation.
WTO (2001b) The German Ecotourism Market. Madrid: World Tourism Organisation.
WTTC (2002) Malaysia: The Impact of Travel and Tourism on Jobs and the Economy. [Online, available
at http://www.wttc.org/publications/pdf/MalaysiaReport.pdf., accessed on August 19, 2006.]
Zaiton, S. (2007) Willingness to pay in a national park in Malaysia: A case study of Taman Negara. PhD.
Thesis, University of Exeter, England, United Kingdom.
245