1. Introduction
In recent decades, visits to national parks have rapidly increased worldwide
[1][2]. National parks (NP) provide diverse ecosystem services, including provisioning services (e.g., wood, water), regulation services (e.g., pollination regulation, air regulation), supporting services (e.g., biomass production, nutrient cycling), and cultural services
[3]. Cultural ecosystem services (CES) refer to those non-material benefits people obtain from ecosystems
[4]. The concept has garnered growing acknowledgment as a useful tool with which to support environmental management and decision making
[5][6][7][8]. Moreover, CES are closely related to humans and have the potential to enhance public awareness of, and motivation for, environmental conservation
[9][10]. NP provide a variety of CES, for instance, NP provide opportunities for individuals to experience nature, engage in recreational activities, appreciate scenic beauty, and enhance their health and well-being, all of which are highly valued and appreciated by the public
[2][11][12]. Moreover, nature-based tourism, one of the CES, plays a pivotal role in generating significant income for national parks, thereby contributing to a sustainable conservation solution
[13]. Furthermore, national parks contain numerous cultural landscapes. The concept of the cultural landscape encompasses a wide array of expressions reflecting the interplay between humanity and the natural world, yielding a multitude of CES. For instance, Maldonado et al.
[14] highlighted the presence of diverse cultural heritage and the extensive cultivation of traditional agricultural systems, including olive groves and other crops, within protected areas and national parks. Cultural landscapes serve as a nexus between nature and culture, encompassing both tangible and intangible heritage, as well as cultural and biological diversity
[15][16]. Nevertheless, the examination of the cultural aspects of protected areas or national parks has progressed slowly and has proven to be intricate. For instance, in most European countries, there is a lack of fundamental identification, inventories, and assessments of cultural landscapes and their associated values within protected areas. Furthermore, cultural values currently have a limited role in Natura 2000 delineation and management, underscoring the insufficient attention dedicated to cultural landscapes
[17][18][19]. Protected areas and national parks have been established worldwide with the primary objective of preserving biodiversity and regulating land use changes. However, managing such areas becomes more challenging in regions dominated by cultural landscapes. These multifunctional landscapes, characterized by cultural features, sustain rich biodiversity and a variety of CES through traditional cultural practices. Managing such landscapes has proven to be a complex task
[20]. The introduction of CES assessment promotes collaborative efforts among various stakeholders involved in protected area management. Collaboration, cooperation, and education are crucial elements in this endeavor
[21]. Developing innovative approaches that foster a comprehensive understanding of CES within NP will enhance the capacity for more effective and holistic conservation. However, cultural landscapes are often inadequately inventoried and evaluated within protected natural areas. For example, Vlami et al.
[19], in their assessment, found that Greece’s primary system of protected natural areas fails to account for “cultural values”, leading to the exclusion of numerous significant cultural landscape features such as archaeological sites and traditional settlements that are in close proximity to or adjacent to these protected zones.
Moreover, the dual function of NP as both tourist and recreational destinations and tools for nature conservation has brought to the forefront concerns regarding environmental issues in these vulnerable protected areas
[22][23]. For example, studies conducted by Balmford et al.
[24] and Aronson et al.
[25] have demonstrated that the recent surge in visitation to places such as U.S. national parks is associated with deliberate or inadvertent visitor behaviors that can harm the natural resources essential for the CES linked to well-being. Gutzwiller et al.
[26] also found that recreational activities in NP have been correlated with declines in biodiversity, including the loss of wildlife, soil, and vegetation. This is why, despite NP being the most commonly employed policy tool for biodiversity conservation, the effective management of NP is frequently hindered by conflicts primarily linked to the social impacts imposed on local communities and other users as a result of their establishment
[3]. Therefore, there is an urgent need to devise better conservation mechanisms that provide clear benefits to people, and capitalizing on CES evaluation may be one way to achieve this goal. The identification of CES furnished by NP and the strategic alignment of management efforts with local concerns can foster trust, garner increased political backing, and ultimately lead to improved environmental outcomes.
At present, the ecosystem services paradigm has been employed to bridge disciplinary boundaries and justify conservation action. However, despite widespread recognition that CES is significant in informing stakeholders and decision makers regarding environmental conservation and management, it too-often remains absent from ecosystem service assessments
[27][28]. This risks a lack of understanding and consideration of CES by decision-makers. Moreover, ecosystem service research has long been dominated by a monetary interpretation of value, neglecting other social perspectives on the importance of ecosystems for human well-being for a long time. To integrate into the ecosystem services framework and support decision-making, it is essential to identify the CES that are provided.
[29]. However, evaluation of CES remains one of the most difficult and least accomplished tasks due to their abstract characteristic
[30]. The limited availability of data presents a significant barrier to assessing CES, and the data primarily need to be collected through detailed and specialized surveys
[31][32]. Furthermore, the demarcation between various CES categories is often unclear, potentially resulting in issues related to double-counting
[30]. For instance, recreation and aesthetics frequently co-occur, making it challenging to differentiate the true value of each service
[33]. Sets of CES that commonly co-occur are referred to as “bundles”, and the interactions between these services can occur as trade-offs, where the enhancement of one service leads to a decline in another, or as synergies, where the utilization of one service directly enhances another. These complexities add to the challenge of assessing CES
[34][35].
In recent decades, significant efforts have been dedicated to the development of methods and tools for assessing CES
[30][36][37][38]. The evaluation of CES has its origins in economic realms during the 1970s and 1980s
[39]. Braat et al.
[36] and Hirons et al.
[38] succinctly categorized these methods into monetary and non-monetary approaches. Monetary methods refer to evaluation outcomes expressed in monetary terms. For instance, “market price” is a monetary method used to estimate the economic values of CES by considering the prices of products bought and sold in the market, such as entrance fees paid at parks for calculating recreation and ecotourism. Non-monetary methods, such as interviews, are frequently employed to gain a deeper understanding of how and why individuals value CES, which can facilitate a better comprehension of those ignored CES such as a sense of place or inspiration. Furthermore, Spangenberg and Settele
[40] and Christie et al.
[37] categorized evaluation methods based on revealed preference and stated preference classifications. For instance, the revealed preference method involves observing actual markets associated with CES or analyzing behaviors and documents to indirectly deduce human preferences for CES; on the other hand, the stated preference method entails creating a hypothetical market and directly asking respondents to express their willingness to pay for CES, or directly inquiring about their values to assess CES. With the development of evaluation methods, diverse CES evaluation studies have been conducted within NP, targeting various specific habitats/ecosystems, such as forests
[41][42], mountains
[11][43], lakes
[11][44], coastal areas
[45][46], and more. For instance, Angradi et al.
[44], in the Great Lakes Areas, conducted their evaluation by analyzing photographs shared on social media. Yoshimura and Hiura
[47] utilized geotagged photos to map the aesthetic value of landscape in NP in Hokkaido.
2. Geographic Distribution
The reviewed studies predominantly focused on Europe, with 77 studies, followed by Asia and North America, with 41 and 24 studies, respectively. Africa contributed 20 studies, with the majority of them concentrated in South Africa, totaling 13 studies. Figure 1 further highlights the top 10 countries, with the USA leading the list with 20 studies. The UK was the second-highest-ranking country, with 14 studies, and south Africa ranked third, with 13 studies. Additionally, five papers encompassed cross-studies conducted in various countries and at the global level.
Figure 1. Geographic distribution of studies.
3. Habitats/Ecosystems of National Parks
Clearly, over half of the studies primarily focused their research efforts on NP as a comprehensive category (122 studies), followed by forests with 22 studies, coastlines with 15 studies, and bodies of water (such as lakes and rivers) with 11 studies. The remaining studies were directed towards mountains, marine areas, wetlands or islands, and others. Please refer to Figure 2 for more details.
Figure 2. NP Habitats/ecosystems of studies.
4. CES Categories
Figure 3 shows that 76 studies were exclusively dedicated to a single service, while 69 studies concurrently explored multiple categories of cultural services. Furthermore, 54 studies comprehensively investigated cultural services as a whole. Figure 3 also illustrates that recreation and ecotourism held the foremost position with 126 studies, followed by aesthetic values with 66 studies, spiritual and religious values with 41 studies, educational values with 40 studies, and cultural heritage values with 40 studies. In contrast, cultural diversity, social relations, and inspiration received comparatively less attention, with 4, 15, and 20 studies, respectively.
Figure 3. Addressed CES categories of studies.
5. CES Evaluation Methods
Twenty methods were employed for evaluating CES within national parks.
Figure 4 illustrates that studies primarily focused on CES predominantly relied on non-monetary methods, totaling 15 methods. Social-media-based methods ranked first, with 49 studies. Various social databases were leveraged, including platforms such as Facebook, Flickr, Google, Strava, Wikilocs, and others, to collect relevant data. For instance, Angradi et al.
[44] downloaded photos from the photo-sharing sites Flickr, Instagram, and Panoramio to evaluate the ecosystem benefits of the Great Lakes areas. Other non-monetary methods, such as interviews and questionnaires, were extensively employed, with 42 and 33 studies making use of these methods, respectively. In addition, quantitative calculations were also prevalent, featured in 37 studies, which assessed CES through the utilization of metrics or indicators. For instance, Tarolli et al.
[48] employed the quantity of nature recreation facilities as an indicator of recreational values. Moreover, there was notable interest in methods associated with participation and mapping techniques, such as participatory mapping (14 studies) and public-participation Geographic information systems (13 studies).
Figure 4. Evaluation methods of CES of studies.
Additionally, this identified five monetary methods, with “travel cost” being the most frequently employed, featured in 11 studies. A comprehensive list of methods and corresponding examples. Furthermore, it is worth noting that more than half of the studies relied on a single method, with only 50 studies incorporating multiple methods. The integration of different methods encompasses a combination of non-monetary methods, a combination of monetary methods, and a combination that incorporates both monetary and non-monetary methods. For instance, Orenstein et al.
[49] employed a combined approach, integrating focus group discussions and scenario simulation methods utilizing an immersive visualization theater (IVT). This methodology aimed to investigate how individuals perceive and value the CES offered by the natural landscapes within Israel’s Carmel Forest National Park. In the IVT setting, 10 focus group discussions were facilitated, wherein a sequence of high-resolution photographs was projected. Participants were asked, both in written form and orally, to select the scenes where they would prefer to spend their time and subsequently provide explanations for their choices.
Additionally, Figure 5 illustrates the distribution of evaluation methods for each year. The majority of studies utilized non-monetary methods, and their usage steadily increased in NP studies, with the exception of a significant decline in the year 2021. The use of interviews and questionnaires has consistently risen over time, while social-media-based methods have gained increasing attention and have recently ranked first in popularity.
Figure 5. The change of the evaluation methods used from 2012 to 2022.
This entry is adapted from the peer-reviewed paper 10.3390/land12101912