Socioeconomic characterization of CKCCNM visitors

The majority of CKCCNM visitors are between 18 and 39 years old, with an average age of 32 years. Males predominate (53%) over females (47%). 93% are Paraguayans, mainly from the Central Department (67%) and Asunción (23%), while the remaining 10% come from other regions of the country or are international visitors. Regarding educational level, 49% have university education, followed by 24% with secondary education, 11% with postgraduate studies, 11% with technical training, and 5% with primary education or other cases. Concerning occupation, 48% are employees, 20% independent professionals, 14% students, 5% unemployed and retired, and 13% other employment categories. Regarding income, 39% earn minimum wage, 29% between one and three minimum wages, 15% four or more minimum wages, and 17% less than minimum wage or no salary.

The results obtained on the profile of CKCCNM visitors show a predominance of young people (between 18 and 39 years) with university education. This pattern coincides with that reported by ^{Caballero Fretes (2021}) in Ñacunday National Park, where 43% of visitors were between 18 and 30 years old and had a university education level. Likewise, studies in urban protected areas of Latin America, such as those conducted by ^{Osorio García, Monge Amores, Serrano Barquín, and Cortés Soto (2017}) in Mexico and Ecuador, highlight that visitors tend to be young adults with motivation for nature tourism.

The high educational level observed in CKCCNM visitors may be related to greater environmental awareness, as suggested by ^{Andrade Navia et al. (2024}), who found a significant association between ecotourism experience and the development of environmental awareness in university students from the South Colombian region. This finding suggests that ecotourism could play a relevant role as an environmental education tool, especially among people with medium or higher academic education.

These findings reinforce the importance of considering the visitor profile in planning management and environmental education strategies, in order to promote greater participation and diversification of audiences in the recreational use of PWAs.

Characterization of visits to the CKCCNM

The majority of visitors surveyed (59%) stated they had previously visited the CKCCNM, while the remaining percentage indicated they were visiting for the first time. Regarding the time of year, 79% preferred the spring-summer months. The main reasons for visiting were nature tourism (49%), relaxation (37%), and educational, sports, and other purposes (14%). The most frequent recreational activities included hiking (34%), observation of columnar sandstone formations (26%), appreciation of local flora and fauna (25%), and cultural aspects and others (15%).

These motives and activities indicated by visitors surveyed correspond to the classification of cultural ecosystem services, which in many cases are conservation objectives of the country's PWAs and particularly of the CKCCNM (^{Millennium Ecosystem Assessment (MEA), 2005}; SEAM, SENATUR and Municipality of Areguá, 2014).

These patterns regarding visitor characteristics are consistent with the findings of ^{Osorio García et al. (2017}), who, in their comparative study between the Nevado de Toluca Flora and Fauna Protection Area in Mexico and the Cotacachi Cayapas Ecological Reserve in Ecuador, identified that the recreational profile is dominant among PWA visitors. Visitors mainly seek experiences of contact with nature, relaxation, and outdoor activities, such as hiking and landscape observation.

Furthermore, in the study by ^{Pérez Gálvez, López-Guzmán, Orgaz Agüera and Prada-Trigo (2017}) on tourists visiting the city of Santo Domingo, Dominican Republic, it was found that visitors' main motivations include the desire to discover new places and disconnect from everyday life, which reflects a search for recreational and relaxation experiences.

The preference for visiting the CKCCNM during summer months also coincides with trends observed in other tourist destinations, where favorable weather conditions and school and work vacations increase visitor influx. For example, in the study by ^{Osorio García et al. (2017}), it was observed that visitors to protected areas in Mexico and Ecuador tend to plan their visits during seasons with more favorable weather and greater availability of free time.

State of services offered and necessary improvements in the CKCCNM, according to visitors' opinions

68% of visitors rated their experience as highly satisfactory, while 19% considered it good; 7% described it as average. The remaining cases (6%) reported a nearly unsatisfactory or unsatisfactory experience. These results reflect a generally positive assessment (87%), although with opportunities for improvement identified by visitors.

The main suggested improvements included the installation of restrooms (17%), placement of benches at viewpoints (14%), access to drinking water (8%), improvement of signage and trail maintenance (7%), presence of tour guides and security (7%), and installation of food and beverage sales points with adequate hygiene and ventilation conditions (4%).

The remaining suggestions (43%) included a varied list of recommendations such as maintaining the current natural conditions of the PWA, enabling attractions like zip lines or soccer fields, carrying out plantings or reforestation in sectors showing signs of degradation or traces of previous fires, equipping the PWA administration with first aid supplies, creating nighttime activities such as museums or exhibitions, installing grilling areas for families, and improving lighting.

All these recommendations are considered pertinent in the context of the PWA's management category and may be considered as valid inputs for updating the management plan whose validity expired in 2019. These suggestions also reflect a clear demand for basic infrastructure that could improve the visitor experience and strengthen the PWA's ecotourism potential, considering that ecotourism attracts part of the global tourism market to natural areas and channels income to local conservation enterprises, thus promoting economic development.

These findings are consistent with observations in other recreational public spaces in the country. For example, ^{Sandoval (2021}), in his study of the Mariscal José Félix Estigarribia Bike Path in San Lorenzo, reported that the main improvement required by users was security service (20%), followed by restroom maintenance (19%) and installation of drinking fountains (19%). Similarly, ^{Portillo (2020}) found that, on the Capiatá Route 1 Bike Path, the installation of restrooms and drinking fountains was identified by respondents as the main need, along with improvements in cleanliness.

These coincidences reinforce the importance of addressing minimum comfort and hygiene conditions in open natural and urban spaces, especially when there is intention to introduce or consolidate ecotourism schemes. Improvement in basic services not only increases visitor satisfaction, but also strengthens the site's attractiveness, its capacity to generate income, and its long-term sustainability.

Willingness to pay for recreational services in an improved scenario

Willingness to pay (WTP) was estimated using the non-parametric model proposed by ^{Kriström (1990}), obtaining an average value of 70,681 ₲ and a median of 65,441 ₲ (Equivalent to approximately 9.2 USD for the average and 8.5 USD for the median, calculated according to the exchange rate in effect at the time of estimation (2025)). Figure 2 illustrates the survival function, which represents the cumulative proportion of visitors willing to pay according to suggested amounts.

Figure 2 Survival function for acceptance of the suggested amount 

As shown in Table 2, 90% of those surveyed accepted paying 16,000 ₲ for admission to the CKCCNM in a scenario of improved services. As the amount increased, the proportion of affirmative responses decreased progressively: 61% accepted paying 36,000 ₲, 43% accepted 76,000 ₲, 26% accepted 116,000 ₲, and only 2% were willing to pay 156,000 ₲. This decreasing distribution of acceptance allows estimation of a reference value for potential implementation of an access fee based on visitor preferences.

This value is similar to that reported by ^{Caballero Fretes (2021}) in Ñacunday National Park, where the estimated average WTP was 66,000 ₲. Both studies, focused on protected areas of high ecological and scenic value, reflect significant valuation by visitors toward recreational use of these natural spaces.

On the other hand, studies conducted in urban environments reveal lower WTP values. ^{Portillo (2020}), in his research on the Capiatá Route 1 Bike Path, estimated an average WTP of 5,200 ₲, while ^{Sandoval (2021}), on the Mariscal José Félix Estigarribia Bike Path in San Lorenzo, found a WTP of 6,900 ₲. These differences can be attributed to multiple factors, such as the nature of the environment (urban vs. natural), the type of experience offered (everyday recreation vs. ecotourism), and visitor expectations.

It should be noted that, as has been widely discussed in the literature, willingness to pay and willingness to accept are not symmetrical, due to differences in how people perceive costs and benefits. Additionally, the hypothetical nature of the scenario presented in surveys may influence responses, since participants do not face real decisions when responding, which may affect the validity of the estimates obtained (^{Mitchell and Carson, 1989}).

The comparison shows that visitors are willing to pay higher amounts to access protected or conserved areas with exceptional ecological and landscape attributes, especially if adequate safety conditions, basic services, and infrastructure are guaranteed. These findings support the possibility of implementing a reasonable entrance fee at the CKCCNM, environmentally adjusted and aligned with the value that visitors assign to the site.

On the other hand, it can be considered that less than 2% of visitors expressed unwillingness to pay for access to the CKCCNM, clarifying that this percentage is relative and depends on the reference amount used. Among the main reasons for non-payment expressed are: "it is a high amount" and "it is a public place and authorities should be responsible for its maintenance." These responses reveal not only economic limitations, but also clear expectations about the State's role in providing and maintaining public goods such as PWAs, mainly those that comprise the public subsystem. Likewise, acceptance of a potential charging system is closely linked to confidence that revenues generated will be managed efficiently and transparently for maintenance or improvement of the same site. Therefore, it is essential to establish solid accountability and transparency mechanisms, as indispensable conditions for socially legitimizing any financing scheme and ensuring its long-term sustainability.

It should be noted that since 2019, Ybycuí National Park has had an entrance fee of 20,000 ₲ for adults and 5,000 ₲ for children, as well as other entrance concepts according to vehicle type, camping services and others, according to ^{MADES Resolution No. 418/19} that establishes income collection rates for PWAs under public domain. This entrance fee was subsequently incorporated into Ñacunday and Cerro Corá National Parks and remains in effect.

The results of this study coincide with those reported by ^{Portillo (2020}) and ^{Sandoval (2021}), who identified economic factors and perceptions about state responsibility as the main reasons for rejecting payment for the use of public spaces. In the case of the bike path studied by Portillo, 57% of survey participants considered the proposed price excessive, while 38% maintained that, since it was a public space, its maintenance should be the municipality's responsibility. Similarly, Sandoval (2021) found that 49% of users opposed payment for economic reasons, and 29% argued that, given that they already contribute with taxes, access to these sites should be guaranteed.

These findings underscore the need for any proposal for access charges or entrance fees to PWAs to consider not only visitors' ability to pay, but also principles of equity and institutional trust. In this sense, it is essential to implement clear communication strategies and participatory mechanisms that strengthen citizen trust, and ensure that collected funds are effectively allocated to improving infrastructure, conserving the area's natural and cultural values, and enriching the visitor experience.

The importance of conducting more research on economic valuation of ecosystem services is also highlighted (^{Amarilla Rodríguez et al., 2023}), with emphasis on valuation of recreational services not only in the country's PWAs, but also in urban green areas.