Uswthul HASANA, Smpd Kumr SWAIN, Bbu GEORGE

a School of Management, Pondicherry University, Puducherry, 605014, India

b School of Business, Alcorn State University, Lorman, 39096, USA

Keywords:

Ecotourism

Protected areas

Bibliometric analysis

Sustainable

development

VOSviewer

A B S T R A C T

Ecotourism projects are mostly implemented in naturally fragile ecosystems as a savior of nature, culture, and indigenous people. This paper aims to make quantitative study of ecotourism in protected areas by using bibliometric analysis. VOSviewer, a popular bibliometric software, was used to analyze as many as 1182 research articles published from 2002 to 2020. Those articles were collected from the Scopus database. The study measured three distinct types of bibliometric indicators (quantity, quality, and structural indicators) to analyze the published articles scientifically. The analysis uncovers ecotourism research in protected areas as an emerging and predominant field of research with a sound growth in annual publications and citations. Importantly, the majority of ecotourism research articles are published in the United States, the United Kingdom, Australia, South Africa, Canada, and China. Nevertheless,ecotourism as a relevant research theme of is getting due importance in African and Asian countries for two key reasons: (1) wildlife and tribal populations, and (2) uncontaminated ecology and environment of ecotourism sites. Further, the main research themes of articles in the field of ecotourism in protected areas are broadly focused on conservation, visitor management,and community. Our findings reveal that controversial issues surrounding ecotourism and its relationship to protected areas, dominated by humanwildlife conflict, gender, and climate change, are attracting the attention of researchers worldwide.

1. Introduction

With the rising attentiveness to the relevance of sustainable tourism development, ecotourism acts as a panacea to offset negative impacts and crusaders of eco-friendly practices (Bagri et al., 2009; Li et al., 2021). This is a responsible form of tourism that constitutes a fair share in contributing to the tourism sector worldwide to be a low impact on socio-cultural aspects and natural resources (Walsh and George, 2019). Ecotourism is characterized by the fewest resources and the highest satisfaction, as it satisfies the need for unpolluted air and uncontaminated water and provides an opportunity for people to immerse themselves in nature. Interaction with tribes or indigenous people and getting their services is the sole instinct of eco-tourists who are otherwise nature lovers.

In this context, ecotourism is an obvious choice of safeguard approach to preserve culture and conserve nature in protected areas. This safeguard approach becomes practically possible through the active and overwhelming participation of indigenous people. This is an empowerment strategy to sensitize the rights, duties, and responsibilities towards ecology and the environment. As such, positive impacts of ecotourism are noticeable as it is a responsible way of providing learning and educative experience with regard to the functions of the natural ecosystems. It is an important goal of ecotourism to protect the ecosystem of human and animal interdependence, and to break the common or unavoidable conflicts. In addition, ecotourism empowers local tribal communities or indigenous people to take ownership of ecotourism establishments and manage facilities, amenities, and services. Considering the importance of ecotourism in a fragile ecosystem, countless research articles from various dimensions of ecotourism in general, especially in protected areas, have been published in the Scopus indexed journals and web of science journals (Pegas and Castley, 2014; Wang et al., 2014; Xu et al., 2014; Pinheiro et al., 2021).

As ecotourism emerged to be a major stream of research over the last two decades, the criticism about it has become more acute. There is very little scholarly consensus about its scope or terms of reference (Fennell, 2014). There have been debates and discussions on the plethora of issues concerning ecotourism worldwide, and people have a deep understanding of the value of ecotourism after the interventions of the United Nations and United Nations World Tourism Organization (UNWTO).

From its introduction as an alternative to mass tourism in the 1980s, ecotourism is now regarded as one of the fastest growing sectors embraced by both developed and developing countries as an approach to sustainable development in ecologically sensitive areas (Fennell, 1999; Dowling, 2013). Protected areas managed by government agencies or Non-Government Organizations constitute a significant segment of the ecotourism market (Honey, 2008).For instance, the International Union for Conservation of Nature (IUCN) is an international organization that categorizes and manages protected areas worldwide (Locke and Dearden, 2005). The IUCN defines protected areas as “a clearly defined geographical space recognized, dedicated, and managed through legal or other effective means,to achieve the long-term conservation of nature with associated ecosystem services and cultural values” (Leung et al.,2018). Until the second half of the 20thcentury, protected areas were managed with the purpose of conservation of endangered species. Subsequently, there was a paradigm shift in converting protected areas into development projects for the larger interest of the community, for which selected categories of protected areas were exposed to projects for sustainable livelihoods of local tribal populations (Torri, 2011). As a result, the introduction of tourism as a development model or means of socio-economic development in protected areas in the form of parks, wildlife sanctuaries, and biosphere reserves was supported in the policy and programs as an inevitable strategy in creating a favorable environment for management of common interests and conflicts (Eagles and McCool, 2002; Spenceley,2015).

Hence, despite being considered sensitive zones, protected areas are open to human disturbances through various development projects (Locke and Dearden, 2005). Negative impacts caused by the growth of mass tourism or overtourism in protected areas affecting their natural and cultural environments have incited many scholars to read and publish research articles on ecotourism in protected areas (Gale et al., 2019). Recommendations that comprise a responsible form of tourism especially ecotourism are a sustainable savior of protected areas (Agardy, 1993; Ceballos-Lascuráin, 1996; Goodwin, 1996). Conventionally, ecotourism in protected areas contributes the conservation of local biodiversity, community development, and education (Fennell and Weaver, 2005).

The concept of practicing principles of ecotourism in protected areas can be traced back to the work of National Park Planning in 1978, stressing a development paradigm that addresses human needs and environmental issues(Honey, 2008). Over time, the importance of ecotourism in aiding the management of protected areas is primarily focused in the IUCN World Parks Congress (Barrios et al., 2003; Ibrahim et al., 2016). The World Ecotourism Summit, a preparatory event conducted to mark the International Year of Ecotourism in 2002, extensively discussed the scenario of ecotourism ventures in protected areas and emphasized on the need for better frameworks and policies of the planning and management of protected areas (World Tourism Organization and the United Nations Environment Programme, 2002).

Nevertheless, the concept of ecotourism is so topical that is vividly debated in academic community due to the complexity in the interests of the involvement of various stakeholders (Jamal and Stronza, 2009) and the lack of consensus on its definitional perspective (Diamantis, 1999; Fennell, 2001; Buckley, 2013). The growing popularity of ecotourism at the global level has opened much scope for increasing ecotourism studies and has made it feasible to add diverse interpretations of its objectives and principles into the diagnosis, analysis, and interpretations. Further,the availability of numerous literature on ecotourism raised the need for carrying out research to review and analyze its characteristics, trends, and impacts. As a result, studies using qualitative and quantitative methods to analyze the trends of ecotourism literature are gaining recognitions worldwide.

Previous studies with the help of bibliometric analysis attempted to explore the trends and prospects of ecotourism research in a general context by using data extracted from the Web of Science database (Liu and Li, 2020; Shasha et al., 2020). Further, Scopus database is also used for a few bibliometric analysis studies on ecotourism literature.However, these studies are focused only on published articles from selected journals on ecotourism (Khanra et al.,2021; Singh et al., 2021). Thus, the present study used Scopus database to fill this gap by employing bibliometric analysis on ecotourism literature. Findings from the previous bibliometric analysis studies on ecotourism have narrowed down to ‘protected areas’ as the principal concept of ecotourism (Liu and Li, 2020; Shasha et al., 2020;Khanra et al., 2021).

Hence, the present study has solely focused on research articles on ecotourism with special emphasis in protected areas. The aims of this study are to (1) analyze the output of ecotourism research literature in protected areas; (2)identify the leading authors, journals, and articles on ecotourism research; (3) explore the trends of research collaborations using co-authorship analysis; (4) identify the key research themes and trends of ecotourism research using co-occurrence analysis; and (5) categorize the research groups and themes with the help of co-citation analysis and bibliographic coupling. The significance of this study is that it brings together a diverse set of perspectives related to the role of ecotourism in protected areas, identifies common themes, and critically examines each of them. In this way, this study contributes to the disciplinization of ecotourism as a legitimate area of inquiry.

2. Methodology

Data for this study were collected from the Scopus database (www.scopus.com), which offers broader coverage of literature. On the one hand, the database is more relevant and useful for smaller research areas. On the other hand, an analysis of data from the Scopus database has added new insights to the findings. Moreover, co-citation analysis can be performed more accurately due to the availability of cited references in the Scopus database (Zupic and Čater,2015). Documents in the form of journal articles have been incorporated for the analysis. Conversely, review articles,book chapters, conference proceedings, and books were excluded from the analysis. Since this study mainly focused on research articles on ecotourism in protected areas, we selected the period of the published articles from 2002 (the International Year of Ecotourism) to 2020. The articles published in English language journals were included for analysis.

The article search was carried out using a combination of keywords. For instance, the categories of protected areas listed by IUCN were used as keywords. Table 1 presents an elaboration of the keywords used, with the number of hits received for a combination of keywords. It also shows the finalized keyword combination that was used to collect the foci articles for the present study. After applying the selection criteria, as many as 1182 articles were collected for executing the bibliometric analysis.

Table 1Search results of keywords from the Scopus database.

Bibliometric analysis can be fundamentally used to analyze scientific literature by quantitative means with the help of bibliometric indicators (Choudhri et al., 2015). There are three types of bibliometric indicators, such as quantity,quality, and structural indicators. All these indicators were measured in this study. For instance, quantity indicators show the productivity of journals or authors; quality indicators measure the relevance and influence of authors,publications, and journals; and structural indicators reflect the relatedness and connection among research areas,countries, and researchers (Durieux and Gevenois, 2010). VOSviewer (Centre for Science and Technology Studies of Leiden University, Leiden, Netherlands), a bibliometric analysis software, was used to quantify the bibliometric indicators. For example, indicators such as the number of citations of the foci articles and the h-index of authors were obtained directly from the Scopus database. The h-index values extracted from the Scopus database were used to identify the prominent authors. This index is a commonly used bibliometric indicator that objectively evaluates the authors’ research output based on their number of publications and the citations received by those publications(Alonso et al., 2009). Figure 1 presents the tools and methods used to assess the bibliometric indicators in this study.

Fig. 1. Tools and methods used to assess the bibliometric indicators in this study.

3. Results

3.1. Annual publications

There has been a steady growth in the number of annual publications on ecotourism research in protected areas,with the publications of 27 articles in 2002 the International Year of Ecotourism, to 126 articles in 2020. Specifically,there were more than 100 articles per year in 2019 and 2020. Figure 2 shows the comparison between the overall trend of annual publications on ecotourism research and ecotourism research in protected areas. As compared to the total articles on ecotourism, almost one-fourth (21.80%) of the total articles were published on ecotourism research from the perspectives of protected areas and their issues, challenges, and prospects during the study period. This has been substantiated with the fact that out of 5422 articles commonly on ecotourism, 1182 articles were published with a special focus on ecotourism in protected areas.

Fig. 2. Comparison between the overall trend of annual publications on ecotourism research and ecotourism research in protected areas.

3.2. Leading journals, authors, and articles

3.2.1. Leading journals

The foci articles comprised the publications from 387 journals. Of the total journals, 242 (62.53%) journals published only one article on ecotourism in protected areas. This implies that more than half of the journals did not specialize on ecotourism in protected areas. Table 2 presents the top 20 listed journals, with 41.70% contributions of the total articles in the field of ecotourism research in protected areas. Among the top 20 listed journals, the Journal of Sustainable Tourism was credited to have 120 articles, as the journal was rated to have the highest publication of articles, contributing 10.15% of the total articles in the research field. The Journal of Ecotourism, with 5.75% of the total articles, was considered to have the second highest record of articles. Other leading journals with focus on articles in the field of ecotourism research in protected areas included the Sustainability (with the contribution of 3.05% of the total articles as the third leading journal), Tourism Management (with the contribution of 2.37% of total articles as the fourth leading journal), and Environmental Management (the contribution of with 2.20% of total articles as the fifth leading journal). We also found that non-tourism journals also published considerable number of research articles in the field of ecotourism in protected areas.

Table 2Top 20 leading journals with higher number of articles in the field of ecotourism in protected areas.

3.2.2. Main authors

The foci articles (1182 articles) comprised the research works of 1000 authors and co-authors. Of these, only 15 authors (1.50%) were successful in having more than five articles (Table 3). Hence, the fewer number of productive authors and their works showed the presence of limited researchers to provide leadership in the subject. This argument was supported by the fact that 76.90% of the authors had only one article in the focus area. The most productive authors were identified in terms of the number of articles, while the influential authors were identified on the basis of the number of citations. However, when the authors were ranked in terms of the number of citations received, there was a significant variation in the order, with authors having less than five articles receiving the higher number of citations.

Table 3Top 20 authors with higher number of articles in the field of ecotourism research in protected areas.

3.2.3. Leading articles

The number of citations an article is cited can be used to measure its quality and influence (Choudhri et al., 2015).Data regarding the number of citations received by the foci articles were extracted from the Scopus database (Fig. 3).The foci articles totally received 20,834 citations.

Fig. 3. Number of citations received by the foci articles in the field of ecotourism research in protected areas.

Table 4 lists the top 10 cited articles in the field ecotourism research in protected areas, which represented 10.35%(344 citations) of the total citations. With these 344 citations, article titled “Ecological footprint analysis as a tool to assess tourism sustainability” received the highest number of citations (Gossling et al., 2002). This article suggests a framework to calculate ecological footprints, focusing on the sustainability issues caused by tourism in protected areas in Seychelle, Africa (Gossling et al., 2002). The article titled “Towards a synthesized critique of neoliberal biodiversity conservation”(Büscher et al., 2012) with 293 citations thus was the second most cited article. It provided a critical account on how neoliberal conservation programs in protected areas and pristine ecosystems focus only on capital accumulation, by ignoring environmental conservation (Büscher et al., 2012). The third highest cited article studied the influence of place attachment on pro-environmental behavior of the visitors in national parks (Ramkissoon et al., 2013). The different research themes of the top cited articles hinted at how the literature addresses the various aspects of ecotourism in protected areas.

Table 4Top 10 cited articles in the field of ecotourism research in protected areas.

3.3. Trends in research collaborations

Co-authorship analysis can help to identify the trends and nature of research collaborations in the study area and find out the presence of research groups in terms of collaborations (Reyes-Gonzalez et al., 2016). As shown in Figure 4, co-authorship analysis revealed the existence of nine clusters, comprising 55 items representing only 1.75% of the total authors. Among the selected authors, 28 authors (50.00%) have published or co-published only one article. This shows the lack of prominent research groups, in terms of author collaborations. Hence, the items in the clusters were formed by the co-authors of the same articles. The co-authorships in terms of author collaborations have taken place mostly among the authors from developed countries like the United States and Canada, and developing countries like China.

Fig. 4. Co-authorship analysis among countries with the publication of articles in the field of ecotourism research in protected areas.

The results of co-authorship analysis showed a considerable number of collaborations among countries. Fifty-seven countries with the number of articles lower than five were selected, and the results are shown in Figure 4. Among the nine clusters, five clusters consisted of more than five items. The first cluster (red color) included 10 items with mainly Asian countries except for Serbia and Romania. The second cluster (green color) included the United States with the largest total link strength (TLS) and was dominated by the African countries. The United States exhibited the maximum collaborations (TLS of 109), followed by the United Kingdom (TLS of 88), Australia (TLS of 71), and South Africa (TLS of 62). The third cluster (blue color) and the fourth cluster (yellow color) comprised nine items,each with a mixture of Asian, European, and African countries. The fifth cluster (violet color) comprised New Zealand, Australia, South Africa, Sweden, Nepal, Finland, China, and Iceland. The highest number of collaborations occurred between the United States and China, the United States and Australia, the United States and South Africa,the United States and Canada, and South Africa and the United Kingdom. Results shown in Figure 4 indicated that the nature of collaborations is not only cross-national but also cross-continental. However, the collaborations among Asian countries and also among African countries were comparatively less, with very few exceptions. Majority of the collaborations took place either between two developed countries or between a developed country and a developing country.

3.4. Key research themes and trends

Keyword co-occurrence analysis can detect the keywords that appear in the same reference, thereby identifying frequently used keywords. The primary study areas in the research field can be explored by identifying the frequently used keywords (Garrigos-Simon et al., 2018). There were 3194 keywords in the selected articles. Apart from‘ecotourism’ (362 occurrence times) and ‘protected areas’ (165 occurrence times) related terminologies, ‘tourism’ (92 occurrence times), ‘conservation’ (84 occurrence times), ‘sustainable tourism’ (84 occurrence times), and ‘sustainable development’ (50 occurrence times) were among the prominent keywords, reflecting the major research object of the foci articles (Table 5).

Table 5Top 20 keywords in terms of occurrences in the articles on ecotourism research in protected areas.

Keywords were further analyzed using VOSviewer, with the minimum occurrence limit to five; 143 keywords were obtained, which were classified into 11 clusters, and each cluster had a specific color. Since the tenth and eleventh clusters had only two and one items, respectively, the cluster size was further updated and the final analysis consisted of nine clusters. Figure 5 represents the network visualization result of keyword co-occurrence analysis by VOSviewer. The keyword ecotourism appeared the most frequently (362 occurrence times), followed by protected areas, tourism, and conservation. Among the protected area categories of IUCN, only national park(s) got featured in the first 50 sets of keywords. The countries highlighted in the list as keywords were predominantly from Central America, Africa, and Asia, thereby proclaiming the presence of a high number of ecotourism projects in those countries. The keywords, which appeared closer to each other, were distinct to have a higher degree of relatedness.Similarly, thicker lines indicated a higher degree of co-occurrences. The first four clusters from the network visualization were briefly described in this section to discuss the prominent research themes.

Fig. 5. Co-occurrence analysis of keywords in the articles on ecotourism research in protected areas using VOSviewer.

The first cluster (red color) included 22 items, with ‘biodiversity’ as the leading keyword. It focused on one of the key aspects of ecotourism-host population with keywords, including ‘local community’, ‘community participation’,‘community-based ecotourism’, and ‘employment’. Based on the components of the second cluster (green color),the next research area was focused on countries, such as ‘Belize’, ‘Mexico’, ‘Kenya’, ‘Ghana’, ‘Uganda’,‘Madagascar’, and ‘Tanzania’. Since all these countries fall under the category of developing and underdeveloped countries, the other keywords in this cluster were ‘participation’, ‘neoliberal conservation’, ‘community’, ‘gender’,‘neoliberalism’, and ‘development’. The combination of keywords in the second cluster put forward some common issues that were confronted during the planning and implementation of the western ideology of ecotourism in the third-world countries (Cater, 2006). ‘Ecotourism’, as the most frequently used keyword, also belonged to this cluster.

Keywords in the third cluster (blue color) were dominated by items related to the screening and monitoring of ecotourism projects. The main items of the cluster comprised ‘management’, ‘GIS’, ‘zoning’, ‘resilience’, and‘monitoring’. The fourth cluster (yellow color) highlighted the fourth research area, which was a different type of combination associated with ecotourism (such as ‘sustainable tourism’, ‘nature-based tourism’, and ‘eco-tourism’)and the terminologies linked to tourists (such as ‘loyalty’, ‘visitor satisfaction’, ‘satisfaction’, ‘service quality’, and‘motivation’). Importantly, the color of the cluster indicated the average year in which the keyword occurrs, in accordance with the legend on the lower-right corner in Figure 6.

Fig. 6. Overlay visualization of keywords in the articles on ecotourism research in protected areas using VOSviewer.

Figure 6 shows an overlay visualization of VOSviewer resulted from the keyword co-occurrence analysis, thus presenting the changing trends in the research area. The clusters, in this visualization, were created by recording the average year in which the keywords appear. Light green and yellow nodes represented the keywords used in the articles that published in the latest years. Purple and dark green nodes indicated the keywords with a higher rate of occurrence in the early stage of the study period. The analysis showed a rising trend in the keyword occurrences,related to the sustainability component of ecotourism. To understand the trend more effectively, we divided the study period into two phases: phase I (2002-2011) and phase II (2012-2020).

Phase I was dominated by keywords encompassing different aspects of ecotourism, such as ‘recreation’, ‘nature tourism’, and ‘parks’, but phase II was predominated by keywords like ‘human-wildlife conflict’, ‘livelihood’, ‘local communities’, ‘climate change’, and ‘community-based tourism’. The ‘gender’ was another notable keyword,appearing in the recent works, thereby implying the growing number of studies on gender and tourism that were previously lacking. Keywords associated with the impacts of tourism activities in protected areas, such as ‘carrying capacity’, ‘climate change’, ‘resilience’, and ‘disturbance’, were also prominently used in phase II during the study period. Keywords like ‘geo-tourism’ and its related concepts, including ‘geological heritage’ and ‘geo-conservation’,were also the part of phase II. Geo-tourism was an emerging niche tourism concept, emphasizing on sustainable development, with its primary focus on landscapes and geology (Farsani et al., 2011).

With the help of overlay visualization, it is possible to explore the trends related to the geographical location studies that are used as keywords. Countries like Belize, South Africa, Peru, Greece, Madagascar, Turkey, China, and Costa Rica appeared in the earlier stage of the study period. Keywords like India, Ethiopia, Malaysia, Serbia, and Nepal have been frequently used as the keywords in the recent stage, implying a rising research trend about the ecotourism ventures in these countries.

3.5. Research groups and themes

3.5.1. Co-citation analysis

Co-citation analysis can identify the intellectual structure of research area (Singh et al., 2022). In order to identify the existing knowledge groups in the field of ecotourism in protected areas, we performed literature co-citation analysis with references as units of analysis. The co-citation analysis of references with a TLS of 14 led the ranking(Scheyvens, 1999). The first cluster contained 28 items, dominated by articles concentrating on the theoretical and conceptual studies of ecotourism (data not shown). The second cluster consisted of articles on an important aspect of ecotourism-livelihood and participation of local communities. The items in the third cluster mainly focused on stakeholder collaborations and partnerships. The fourth cluster represented the articles that studied the aspects of ecotourists, such as behaviors, attitudes, segmentations, and motivations of the tourists. Many ecotourism articles studied these attributes to measure the pro-environmental behaviors of tourists in protected areas (Cheung and Fok, 2014).Articles in the fifth cluster were focused on two aspects: (1) the contributions of tourism programs to protected areas and (2) the community aspects of tourism. The sixth cluster had a mixed area of articles. The seventh cluster focused mainly on the economic impacts of recreational activities, especially in the marine protected areas. However, the remote placement of this cluster indicated low frequency of co-citations with other areas of research. The domain area of the eighth cluster with seven articles was related with tourism in protected areas.

The co-citation analysis on sources revealed the journal co-citation network with four clusters containing 85 items(Fig. 7). The research theme of the sources (journals) can be categorized as tourism, ecology, conservation, and economics. Journals in the green cluster, namely, Tourism Management (TLS of 1126), Journal of Sustainable Tourism (TLS of 1084), Annals of Tourism Research (TLS of 861), and Journal of Travel Research (TLS of 446)were the leading journals in co-citation network of sources. The shorter distance among the nodes of Tourism Management, Journal of Sustainable Tourism, and Annals of Tourism Research also implied a greater co-citation frequency. The green cluster comprised 23 items, which were predominantly tourism-related journals. Moreover,journals in the blue cluster were mainly focused on ecology and conservation. Items in the yellow cluster and red cluster included journals from mixed research areas. The short distance between the clusters denoted that the cocitation frequency among the corresponding journals was low.

Fig. 7. Source co-citation analysis in the articles on ecotourism research in protected areas.

3.5.2. Bibliographic coupling

Bibliographic coupling can find out whether two articles have cited the same third article as reference, thereby assuming that these articles might have a relatively common objective (Freire and Verissimo, 2020). For the purpose of this study, we performed bibliographic coupling analysis by keeping articles as the unit of analysis. Therefore, 322 articles met the threshold by keeping the minimum citations of 20. Among the 322 articles, 314 publications were connected to each other, forming 11 clusters, as shown in Figure 8 (Prominent articles included: Scheyvens, 2000;Lawton, 2001; Marker et al., 2003; Tao et al., 2004; Herrero et al., 2005; Lindsey, 2005; Nagendra et al., 2005;Spenceley, 2006; Asafu-Adjaye and He, 2008; Schianetz, 2008; Tapsuwan, 2008; Newsome and Davies, 2009; Reyers et al., 2009; De Groot, 2010; Dolnicar, 2010; Bscher, 2012; Fassoulas et al., 2012; Vianna et al., 2012; Devine, 2014;Saayman et al., 2016; Cetin et al., 2018; Sala and Giakoumi, 2018; and Gale et al., 2019).

Fig. 8. Bibliographic coupling of articles related to the theme of ecotourism in protected area.

The first cluster (red color) was the largest in terms of total number of items (54). The main research theme of these articles can be divided into two aspects, namely, conservation and visitors in ecotourism ventures. The articles that deal with conservations focused on the effects of ecotourism on the flora and fauna of protected areas. While some of articles in this cluster focused on promoting ecotourism as catalyst for conservation, most of these studies were about the negative effects of ecotourism related activities on the wildlife that inhabit protected areas. The study of tourist preference and satisfaction was another research area of the cluster.

The second cluster (green color) comprised 44 items. The articles in this cluster focused mainly on the impacts of tourism in protected areas. The highest cited article (Gossling et al., 2002) among the foci articles also belonged to this cluster. Majority of the articles were related with the impacts of visitor flow and recreational activities on protected areas (Gossling et al., 2002). The influence of environmental education or interpretation, which was one of the main components of ecotourism (Blamey, 2001) on minimizing the impacts of tourists on protected areas, formed the subcategory of the second cluster’s research area (Marion and Reid, 2007; Littlefair and Buckley, 2008).

While the research theme of the third cluster (blue color) was mixed with articles on a variety of topics, a considerable number of articles focused on the communities living in and around protected areas. The fourth cluster(yellow color) comprised 33 items and two prominent research themes. Although a set of articles was on the typologies and attributes of ecotourism, the other set of articles from the fourth cluster focused on the framework and conceptual part. Similarly, the fifth cluster (purple color) also had two research themes related to ecotourism products and tourist motivations.

With 29 items, the sixth cluster (light blue color) covered themes combing sustainable tourism development and stakeholder participation in protected area management. The seventh cluster (orange color) consisted of 28 items. The research area in most of the articles in this cluster embraced tourism in marine protected areas. Articles in the eighth cluster (brown color) included studies on geo-tourism and tour guides. Livelihood contributions and economic benefits to the local communities were the research themes of the ninth cluster (pink color). The tenth cluster (violet color) was focused on different research themes, including transport and governance. The last cluster, i.e., the eleventh cluster (light green color), comprised eight items related to sustainable development.

4. Discussion

From a steady rise in annual publications and citations to the emergence of ecotourism research themes, it is safe to suggest that research on ecotourism in protected areas is growing quantitatively and qualitatively. Keyword cooccurrence analysis can help in investigating the major research themes and the change of trends in research interest throughout the study period. The research areas covered a wide range of themes dealing with the objectives of ecotourism in protected areas. Especially, there was a paradigm shift in the second half of the study period, with more focus on the key sustainability issues. The frequent occurrence of gender, which appeared as a keyword in the second half of the study period, implied the importance of gender issues in terms of participation and involvement of women in ecotourism projects. Many ecotourism ventures in the developing countries faced challenges, coping with the traditional gender roles of the destinations (Panta and Thapa, 2018). Nevertheless, the success stories of a few ecotourism projects proved that ecotourism can promote women’s empowerment and gender-neutral approach(Scheyvens, 2000).

Even though the Local Agenda 21 insists on the need for participation to achieve development, communities living in and around ecotourism ventures in the third world countries have only limited access to participation and benefits(Mowforth and Munt, 2015). A wide range of keywords related to community demonstrated the availability of literature perusing the host community aspects in ecotourism ventures (Stem et al., 2003; Jamal and Stronza, 2009).By combining the results from keyword co-occurrence and co-authorship analyses based on countries, it is evident that, despite the fact that the majority of the studies were focused on developing and least on developed countries, the authors were predominantly from developed countries, with a few exceptions like China and South Africa. However,there was also a rising trend of publications from African and Asian countries.

Co-citation analysis used references to form clusters, covering various components of ecotourism, such as conservation, participation, and benefits. This result was complimented by the results from bibliographic coupling analysis, with articles as the unit of analysis. These two analyses exposed the existence of literature, sharing similar objectives and research themes. Studies on ecotourism visitors, local communities, and conservations emerged as the major focus area. There were also a considerable number of articles focusing on the conceptual aspect and framework formation.

Geo-tourism, as an alternative form of tourism, is becoming a new branch of natural regional tourism, which is practiced in areas with prominent geological landscapes (Farsani et al., 2011). As ecotourism and geo-tourism share many commonalities, in particular as a common focus for sustainable development and as both are practiced in fragile protected environments, a small section is devoted to geotourism and its related concepts, such as geo-heritage and geo-conservation. The growing significance of geo-tourism, which is considered as a “new ecotourism”, can be attributed to the increasing number of geo-parks promoted by the United Nations Educational, Scientific and Cultural Organization (Dowling, 2011). The sources of the articles were mainly journals, focusing on tourism and ecology.While these two fields are very important components of ecotourism ventures in protected areas, the human aspect of ecotourism cannot be completely neglected. However, anthropological and development-related journals have contributed relatively little to this field of study.

5. Conclusions

Using bibliometric analysis, the present study provided a comprehensive overview of the literature on ecotourism in protected areas, with the aid of three bibliometric indicators: quantity, quality, and structural indicators. The results indicate that there was a steady growth in publications with significant increase in citations, which implies that ecotourism in protected areas was a significant research area. The foci articles comprised 387 journals as sources,with contributions from 1000 authors. Higher number of journals and authorship suggest that ecotourism in protected areas was a hot research area. Journal of Sustainable Tourism, Journal of Ecotourism, Sustainability, Tourism Management, Environmental Management, Wit Transactions on Ecology and the Environment, and International Journal of Sustainable Development and World Ecology were the leading journals. In terms of collaborations, there was a lack of associations among developing countries. Majority of the associations were either between two developed countries or between a developed country and a developing country. The United States was the most productive country, followed by the United Kingdom, Australia, South Africa, Canada, and China. The United States also had the highest number of collaborations with other countries. Co-occurrence analysis showed the key research theme and trends. Carrying capacity, communities, climate change, gender, conservation, human-wildlife conflicts,and geo-tourism were the research themes with more occurrences in the recent studies. Co-citation and bibliographic analyses presented an intellectual structure of the study area by identifying the research groups and themes.

The present study was based on the bibliometric analysis on data extracted from the Scopus database. We recommend that future studies can be done using multiple databases and qualitative analysis to compliment and further expand the research findings.

Declaration of Conflicting Interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

We would like to thank the reviewers for their insightful comments in improving the manuscript.