Introduction

A grassland ecosystem is a functional complex composed of biological communities dominated by various perennial herbs and their environment. It is one of the ecosystem types with the largest land area, occupying about 40% of the earth’s land area1. The magnificent and vast grassland landscape and unique folk customs make grassland ecosystems famous ecotourism destinations, which are favored by many tourists from all over the world2. However, due to the influence of natural conditions and human recreation activities, a series of problems threaten the ecosystem integrity of grassland destinations, such as desertification, salinization and pollution3. Grassland ecosystems are in urgent need of protection and restoration, but the shortage of protection funds is a common problem in many grassland tourist destinations3. How to raise sufficient funds to support the restoration and protection of grassland tourism ecosystems, and stimulate the sustainable development of grassland tourism, has become a key area of attention for scholars4.

It is widely recognized that incorporating social capital, such as tourists paying for environmental protection, is a crucial strategy to address funding shortages4. Additionally, investigating tourists’ Willingness-To-Pay (WTP) and its influencing factors can help make tourists aware of the economic value of the ecological environment, thereby enhancing their environmental protection awareness. Previous research has primarily explored the determinants of tourists’ WTP for environmental protection from the perspectives of social and economic characteristics5,6, as well as tourists’ cognition and environmental awareness7,8. Tourists’ WTP for environmental protection reflects their preference for conserving the destination’s environment, which may be influenced by the restorative qualities of the destination’s environment. Consequently, this study examines the incentive mechanisms behind tourists’ WTP for environmental protection from the perspective of the destination’s restorative environment.

The beautiful natural ecological environment has the function of improving tourists’ mood and reducing stress. This environment that can promote physical and mental healing is called a restorative environment9. Relative to the urban built environment, the outdoor natural environment includes more restorative elements, and the restorative value of the ecotourism land is the most prominent10. ecotourism destinations bring strong sensory resonance to tourists with their rich original ecological landscape, which can obtain a deep restorative experience11. The Perceived destination restorative qualities (PDRQs) have become an emerging research field, Existing research results have mainly focused on the scale development of RDRQs12,13, recovery benefits of different tourism environments14, antecedent factors15 and impact consequences (pleasure, health, subjective well-being, place attachment, visitor loyalty, environmentally responsible behavior, etc.)16. However, the influence mechanism of RDRQs on WTP for environmental protection remains a research blank.

Well-being has always been one of the most important pursuits of mankind, and has been identified by the United Nations as a vital goal for sustainable development17. Current consumption trends also suggest that well-being as a desired result of travel is growing exponentially18. The image of a destination shapes the original idea of a place19,20. In recent years, with the increasing demand for ecological and socially responsible travel, the image of ecotourism destinations has become more important21. PDRQs can promote tourists’ EWB, which in turn promotes positive and friendly behaviors among tourists22, and also helps to establish the image of an ecotourism destination11. However, the impact of tourist EWB and ecotourism destination image (EDI) on WTP for environmental protection and whether they make a mediating impact between PDRQs and WTP are unknown.

Based on the above study gaps, this study selected Hulunbuir Grassland, one of the most well-known grassland ecological tourism destinations in China, as the research site. The present study aims to introduce the Reasonable Person Model (RPM), study how PDRQs, EWB, and the image of an ecotourism destination affect the of tourists’ WTP for environmental protection, and try to achieve the following three goals: (1) to explore the causal relationship between PDRQs, tourists’ EWB, the EDI and WTP for environmental protection; (2) To test the intermediary effect of tourists’ EWB and the image of an ecotourism destination between PDRQs and WTP for environmental protection; (3) To verify the adaptability of RPM in predicting tourist WTP for environmental protection.

Literature review and research hypotheses

When tourists perceive the restorative environment of a destination, it may evoke positive psychological feelings, which in turn can lead to positive behaviors. RPM elucidates the relationship between environmental factors and human behaviors, aligning well with the objectives of our research. Therefore, in this study, we introduce the RPM to uncover the process and mechanism of action of PDRQs on WTP for environmental protection.

Rational person model

Kaplan & Kaplan23 proposed the RPM from the aspect of environmental psychology. This model reveals how environmental factors are linked to human behavior, explaining the benefits of the natural environment to humans from a holistic and systematic perspective24. The RPM is defined into the following three stages including model building, effectiveness, and meaningful action23. When the public is in an environment that fascinates them, introduces them, and is in tune with their needs (model building), they recover from fatigue, stimulate their potential, and form a cognitive and emotional connection to the environment, thus triggering meaningful action25. Some scholars have used RPM to explain the environmentally responsible behavior of residents and tourists22,26, such as Qiu et al.22 used RPM to test the causal correlation between PDRQs, EWB, hedonic well-being, and tourist environmentally responsible behavior (ERB). However, the aforementioned research primarily examines the influence mechanism of PDRQs on general environmentally responsible behavior, rather than a specific pro-environmental action. Goh et al.27 have suggested that future studies should focus on a single pro-environmental behavior within a specific context. In line with this recommendation, the study concentrates exclusively on tourists’ WTP for environmental protection.

According to RPM, the relationship model of PDRQs (model building stage), EWB and EDI (effectiveness) and WTP (meaningful action) is constructed to clarify the mechanism of action of PDRQs on WTP for environmental protection.

Model construction stage allows tourists to actively engage with and explore the environment, interact with environmental stimuli, and experience the restorative benefits it offers28,29. By effectively managing and processing the stored environmental memories and experiences, tourists can enhance their self-confidence and awareness, recover from fatigue, and gain renewed energy for daily activities24,30,31. This process also stimulates positive cognitive and emotional evaluations of the destination image11,32,33,34. Finally, meaningful actions are manifested through behaviors, attitudes, beliefs, active listening, mutual respect, and the expression of opinions23.

Perceived destination restorative qualities

PDRQs are referred to as the restorative attributes of destination-specific conditions as perceived by tourists12. Attention Restoration Theory states that the restorative environment can restore the previously depleted cognitive resources to promote physical and mental health, while the restorative environment experience should include being-away, fascination, extent and compatibility as four characteristics35. Lehto12 measured PDRQs and developed a measurement scale with six dimensions (including compatibility, extent, mentally away, physically away, discord, and fascination) to comprehensively assess the recovery potential of the vacation experience. Lehto et al.13and Chen et al.16 combined the characteristics of Chinese tourists and verified and corrected the PDRQs scale. Previous research has demonstrated that the PDRQ scale holds certain applicability in various contexts. However, its suitability for grassland eco-tourism destinations remains to be empirically tested.

In addition to the scale development, the study of PDRQs also consists of three levels: first, exploring the recovery benefits of the different environments, such as the urban green space36, forest37; second, examining the environmental familiarity38, local memory39 and the relationship with restorative perception; third, investigating the role of restorative perception on environmental preference14, emotional health40, tourist loyalty41, environmental responsible behavior33, etc. This paper introduces PDRQs into the context of environmental protection, and discusses the changes in emotion, cognition and behavioral intention when tourists experience the restorative effect.

Eudaimonic well-being

Tourist well-being can be referred to as the emotional pleasure and self-perception of tourists’ growth during the process of meeting different sensory needs and realizing tourism goals32,42. Tourist well-being is regarded to include two dimensions: Eudaimonic well-being(EWB) and Hedonic well-being43,44. EWB reflects the inner feelings of tourists’ self-growth, such as the realization of personal potential and self-realization; while hedonic well-being reflects the emotional pleasure of tourists’ satisfying their sensory needs42,45. Tourists in the process of pursuing hedonic well-being show more individualism46, which makes it difficult to exhibit altruistic behavior. EWB is a more meaningful spiritual experience; tourists in the destination recovery environment increase their personal potential and self-realization, enhance their personal resonance and contact to the destination, and are more likely to promote altruistic behavior47. Previous literature has emphasized that PDRQs can efficiently promote the recovery of mental fatigue and improve tourist well-being9,16,22,48. Jiang et al.49 verify the healing effect of nature on tourists in the context of Chinese natural heritage, and explain the potential mechanisms linking nature and subjective well-being. Lin & Hsieh50 confirmed that the resilience and perceived recovery formed during tourism have a significant direct effect on their happiness. Zhang et al.14 confirmed that PDRQs are important predictors of tourist subjective well-being in both urban parks and national parks. In conclusion, PDRQs play a vital role in promoting the mental, emotional and physical well-being of tourists. Therefore, the following hypotheses are proposed:

Hypothesis 1: Perceived destination recovery quality makes a positive impact on eudaimonic well-bing.

Ecotourism destination image

Usually, the destination image is usually referred to as the overall perception and psychological description of a tourist’s evaluation towards a specific destination. Generally speaking, the destination image consists of two dimensions including cognitive and emotional34,51,52. Cognitive evaluation refers to tourists’ cognition and beliefs about destination attributes, whereas emotional evaluation describes tourists’ feelings and attitude towards these attributes53,54. In addition, this also applies to research related to ecotourism destinations. When tourists visit an ecotourism destination, they will develop a cognitive evaluation and positive emotional evaluation towards its attributes52.

There exists a significant difference between ecotourism destinations and tourists’ habitual living environment, and tourists are more easily attracted to the destination’s natural features. The restorative environmental attributes of ecotourism destinations, such as being-away, fascination, extent and compatibility, can promote tourists to form a cognitive understanding of the destination’s ecological resources and landscape, good ecological environment, and ecological harmony, improve their sense of belonging and congruence with the destination, and trigger positive emotional attitude of tourists to their destination. In other words, once tourists feel the restorative properties of the ecotourism destination environment, such as being-away, fascination, extent and compatibility, they will regain their self-awareness55,56, arousing positive cognitive and emotional evaluations towards the ecological destination image11. Therefore, the following hypothesis can be proposed:

H2: Perceived destination recovery quality makes a positive impact on EDI.

WTP for environmental protection

WTP is commonly utilized as a method for evaluating the value of non-marketable goods. Tourists’ WTP for environmental protection reflects their preference for environmental protection, which can be influenced by their perception of the destination’s restorative environment. Previous studies have identified that the restorative environmental attributes of ecotourism destinations, such as rich content, charm, and the sense of being-away, can help tourists temporarily forget trivial matters, integrate into the local environment, and experience new things. These attributes can encourage ecotourists to engage in positive and meaningful behaviors, including pro-social behavior, environmental protection behavior, and payment behavior33,40,57,58. Collado & Corraliza59 found that the charm dimension of perceived restorativeness significantly impacts pro-environmental behavior. Chiang60 demonstrated that compatibility, a component of restoration, is the sole direct predictor of pro-environment behavior. Zhou et al.33 reported that the three dimensions of PDRQs—compatibility, extent, and being-away—influenced tourists’ pro-environment behavior through place attachment. In this study, when examining the relationship between PDRQs and tourists’ WTP for environmental protection, PDRQs are considered a second-order factor. This article proposes the following hypothesis:

H3: Perceived destination restorative quality has a positive impact on WTP for environmental protection.

Existing research indicates that tourists’ happiness can result in a range of behavioral consequences, such as revisiting or recommending intentions61, willingness to pay62, and sharing travel experiences63. Wang et al.41 and Su et al.42 have argued that emotional attitudes can effectively guide tourists towards environmentally responsible behavior (ERB). Kaida & Kaida64 found that residents’ ERB is positively correlated with subjective well-being. Tourism well-being consists of two dimensions: EWB and hedonic well-being. EWB is associated with representing higher-level human needs such as personal potential and self-actualization, while hedonic well-being is associated with representing lower-level basic human needs42. EWB is more likely to promote the generation of meaningful altruistic behavior22. As a result, this article puts forward the following hypothesis:

H4: EWB makes a positive effect on WTP for environmental protection.

According to the resource-rational analysis model, effectiveness exerts a mediating role between model establishment and meaningful actions. According to the proposed model, Wang, et al.41 found that tourist well-being, serving as an effective indicator, makes a mediating impact between PDRQs and environmentally responsible behaviors (ERBs). Qiu et al.22 discovered that EWB mediates the association between restorative environment in vacation destinations and ERBs among tourists. The present study attempts to explore the mediating effect of tourists’ EWB from a psychological perspective, with happiness and health as the core factors. Happiness and health refer to the psychological connection between tourists and the destination, as well as the meaningful spiritual experience obtained at the destination42. Thus, this article puts forward the following hypothesis:

H5: EWB mediates between PDRQs and WTP for environmental protection.

Tourists demonstrate a greater inclination to engage in positive behaviors towards tourist destinations or products that possess a green, sustainable, and ecological image65. Additionally, tourists display WTP for sustainable tourism products66. Nelson et al.67 assert that a hotel’s environmentally friendly, energy-saving, and green image prompts tourists to pay a higher price. Can et al.68 found that tourists have a willingness to pay a premium for destinations with a Blue Flag image. Moreover, Pham & Khanh69 found that the image of ecological destinations positively influences Vietnamese tourists’ attention and protection actions towards ecological and environmental issues. Building upon existing literature, this work posits the following hypothesis:

H6: EDI makes a positive impact on WTP for environmental protection.

The establishment of destination image in ecotourism is a positive cognition and emotion of tourists towards destination’s ecotourism. Previous studies have verified the mediating role of destination image. For instance, Chew et al.34 verified the mediating role of destination image between perceived risk and intention to revisit. Similarly, Huang & Lin70 indicated that destination imagery serves as a mediator between tourist learning and destination attachment. Chiu et al.52 validated the mediating role of destination imagery in tourist cognition and environmentally responsible behavior. Additionally, Li et al.11 confirmed that EDI mediates the correlation between tourist destination experience and destination loyalty. Therefore, this article puts forward the following hypothesis:

H7: EDI mediates between PDRQs and WTP for environmental protection.

This article presents a research model (Fig. 1) based on the aforementioned research hypotheses.

Fig. 1
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Research model.

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Methodology

Research site

The Hulunbuir Grassland, situated in the Inner Mongolia Autonomous Region, China, was chosen as the research site for this study (see Fig. 2). Hulunbuir Grassland is one of the four major grasslands globally, a world-renowned natural pasture, and the most famous and well-preserved grassland ecotourism destination in China. It is situated in the northeast of Inner Mongolia Autonomous Region, west of the Daxing’an Mountains, with a total area of approximately 113,000 square kilometers. The Hulunbuir Grassland area is vast, with over 3,000 crisscrossing rivers and over 500 scattered lakes71. Furthermore, the Hulunbuir Grassland boasts a long history of humanities and is an important birthplace of hunting and nomadic ethnic groups in northern China, and being home to various ethnic groups such as the Xianbei, Khitan, and Jurchen. The Hulunbuir Grassland attracts domestic and foreign tourists with its good ecological environment, and rich flora and fauna resources. In 2023, Hulunbuir received a total of 29.2225 million tourists72.

The Hulunbuir Grassland has been designated as a restricted development zone in China’s main functional area planning. The primary objective of this development zone is to safeguard the ecological environment and offer an ecological barrier for northern China73. Consequently, the development of various industries in the Hulunbuir Grassland is restricted, and problems such as slow economic development and insufficient protection funds are increasingly emerging. Finding ways to generate funds to support ecological protection in the Hulunbuir Grassland while promoting local economic development has become an important social issue. Recently, a series of ecological and environmental issues, such as grassland desertification and soil erosion, have emerged in the Hulunbuir Grassland due to changes in the natural environment and factors such as tourism and grazing. As a result, the protection and restoration of the ecological environment have become paramount in Hulunbuir4. Therefore, Hulunbuir serves as an appropriate and representative case site.

Questionnaire design

Fig. 2
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Scenic views of Hulunbeie Grassland.

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To make the collection of data, this study utilized a questionnaire survey. The questionnaire included three parts: the first part included three variable measurement scales. To be specific, 26 projects from Chen et al.16 were adopted for measuring PDRQs. The measurement of EWB comprised four items: sense of achievement and satisfaction, triggering thinking, meaning in life, and positive attitudes22. Cognitive and emotional dimensions were used to gauge the destination image, encompassing five items11,51,52, all assessed using a five-point Likert scale; The second part focused on tourists’ WTP for environmental protection. If tourists are willing to pay, please choose one of the nine amounts that they are willing to pay, including 5 CNY, 10 CNY, 20 CNY, 30 CNY, 50 CNY, 80 CNY, 100 CNY, 120 CNY, 150 CNY and above. The suitability of these nine amounts has been verified in previous studies4, and the level of WTP is also measured by 1–5, namely 5 CNY to 10 CNY, 20 CNY to 30 CNY, 50 CNY to 80 CNY, 100 CNY to 120 CNY, 150 CNY and above, respectively recorded as 1, 2, 3, 4, and 5. In cases where tourists were unwilling to pay, they were asked to provide reasons for their decision. The third part captured demographic information of respondents, which included age, gender, education level, and income. Five experts in the tourism related field will review the measurement items of the questionnaire to check the scientific nature of the presentation, i.e. whether these items are suitable for the environment of the ecotourism destination.

Pretest

In order to lower sampling error and improve accuracy, a pre-test was conducted in June 202374. Questionnaires were distributed to tourists at major tourist attractions on the Hulunbuir Grassland. A total of 154 eligible tourists completed the questionnaire, of which 137 were valid. After excluding 26 protest responses (respondents unwilling to pay for reasons other than inability to pay), 111 questionnaires were adopted for exploratory factor analysis (EFA) and reliability analysis.

With the application of SPSS 26.0 software, based on 111 subjects in the pre-test, EFA and reliability analysis were performed on the 26 items of PDRQs using the maximum variance rotation principal component method. The result of the Kaiser-Meyer-Olkin test (KMO = 0.892) and Bartlett’s test of sphericity (χ2 = 1909.468, df = 325; p < 0.001) indicated that conducting factor analysis was suitable75. We removed items with factor loadings of less than 0.5 and items cross-loaded on two factors with factor loadings of greater than 0.4 (P1, P8, P9, P10, P17, P22, P23, P24, P25, and P26). EFA was again conducted on the remaining 16 items. The KMO was 0.868 and the BTS (χ2 = 883.261, df = 120, p < 0.001) was significant. As presented in Table 1, three factors (with eigenvalues greater than 1) were extracted from the items of PDRQs, which included Away, Compatibility, and Extent, they explained 60.562% of the total variation. After the deletion of items, factor loadings of all the items exceeded 0.5 (Table 1). The Cronbach’s alpha of the variables and their dimensions ranged from 0.740 to 0.887, exceeding the recommended level of 0.776. Therefore, in subsequent analyses, this study used the three dimensions of Away, Compatibility, and Extent to measure PDRQs.

Table 1 Exploratory factor analysis results (N = 111).
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Sample and data collection

The formal survey was performed from July to October 2023, which is the peak tourist season in Hulunbuir, and the research team carried out the formal survey at popular and typical tourist attractions in Hulunbuir, such as Jinzhanghan and Muyunshan Peak. The questionnaire survey used a convenience sampling method, which is suitable for on-site tourist surveys and is often used in tourism research77. The researchers informed the respondents of the aim of the questionnaire survey (only for academic research) and requirements (to answer honestly according to their tourism experience in Hulunbuir), and ensured anonymity. The researchers proposed two screening questions: whether you are a tourist from other regions visiting Hulunbuir; how many days have you traveled in Hulunbuir? We provided options for tourists to choose from in the questionnaire.Local visitors to Hulunbuir and visitors who have not yet played for a day were all excluded from the survey. In the end, a total of 505 eligible tourists completed the questionnaire. After excluding invalid questionnaires, 426 valid questionnaires were retained, with the effective rate of 84.4%.

The sample number might be ascertained according to Scheaffer et al.78,

$$n=\frac{N}{(N-1)\delta^{2}+1}$$

where n is the sample number, N is the total number of tourists in the Hulunbuir in 2023, and δ is the sample error. In this study,δ = 5%, N = 292,225,000, and n = 400. Therefore, the sample size of this study can represent the tourist group.

Data analysis

We used a three-stage method for validating and determining the formal survey questionnaire as well as examining the relationship of the hypothesis model framework74. In the first stage, a preliminary survey questionnaire was initially drafted and a pilot study was conducted. SPSS 26.0 was initially employed to analyses the data. EFA and reliability analyses were conducted for pre-test data. The structure and items of the PDRQs were extracted and categorized using EFA, and the reliability of the questionnaire was analyzed with Cronbach’s alpha. In the second stage, after the data collection of formal questionnaire, the demographic characteristics and the reasons for protest responses of the respondents were analyzed, and Smart-PLS 4.0 was used to perform CFA to evaluate the measurement model. As shown in the third stage, partial least squares structural equation modeling (PLS-SEM) was adopted for testing the causal relationships between variables. One advantage of the PLS modeling approach lies in its ability to produce robust results79. The PLS-SEM modeling technique utilizes the iteration approach thus could produce robust results and is not restricted by the requirements of covariance based SEM (CB-SEM) such as sample size and normal distribution assumption79. In addition, the high statistical power of PLS-SEM approach helps researchers to identify relationships when they are indeed present in the population79, thus PLS-SEM is also advantageous when the research is explorative or the model is complex80. One task of this paper is to try to probe the position of PDRQs in the relationship web. Tentative exploratory models are not suggested to be analyzed with the full information that CB-SEM method requires79. Besides, the model of this study included 25 indicators under 6 first-order latent constructs, and 1 s-order construct is involved in the model. The complexity of variables and relationships fits the PLS-SEM approach. Therefore, SmartPLS 4.0 was used to analyze the data.

Results

Profile of respondents

Table 2 displays the demographic information of the respondents. Among the 426 respondents, females (57%) were slightly more than males (43%). In terms of age, the highest proportions were 25–44 years old and 45–64 years old, accounting for 45.1% and 35.9%, respectively. Regarding education, those with degrees of junior college and bachelor’s degrees accounted for 41.8% and 40.6% of the sample, respectively. Respondents with an annual income range of 50,001–80,000 CNY (30.0%) and 80,001–120,000 CNY (33.3%) constituted the largest proportion of the participant group.

The socio-economic profile of the sample in this study closely mirrors that of Hulunbuir tourists reported in 2019, as documented by Wang and Ya4. According to their research, the majority of tourists were aged 25 and above, with a predominant educational attainment of junior college or higher (67% held a college degree or higher). Additionally, over 85% of the respondents reported an annual income exceeding 40,000.

Table 2 Demographic profile of respondents (N = 426).
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Reasons for unwillingness to pay

In the formal survey stage, 81 tourists out of 426 valid questionnaires were unwilling to pay. Among them, more than half of the tourists (59.3%) were unwilling to pay because they considered that it was the government’s responsibility, 23.5% of the tourists believed that whoever caused the damage should pay, 13.6% of the tourists believed that they could not benefit from it, and 3.7% of the tourists did not believe that the money would be used effectively. This indicates that many Chinese people have not yet formed the concept of paying for ecological resources and environmental protection, and ecological environment protection mainly relies on government funding support.

None of the tourists who refused to pay did so because the amount was too large, and these responses were considered protest responses81. Protest responses represent the impact of the used heuristic method, rather than the expression of true evaluation of the project82. Protest responses may seriously affect the results of evaluation research83, so we do not include protest responses in subsequent analyses. Totally 345 questionnaires were adopted for the analysis of measurement model and structural model, and the sample size exceeded the five-fold threshold of the total number of all indicator variables75.

Common method deviation

With the purpose of ensuring the accuracy of data analysis, Harman’s one-factor test was used for demonstrating CMV before formal data analysis. EFA was conducted with SPSS 26.0 software. According to the results, the total variance explained by the first factor at the unrotated stage was 49.58%, which was less than 50%84, indicating that the CMV was not a concern.

The first-order measurement model with five factors consisting of 25 measurement items was tested using CFA, Table 3 reports the internal consistency reliability, convergent validity, and discriminant validity. With the use of CR, internal consistency reliability was measured, and the CR values of all constructs ranged from 0.873 to 0.918, which were higher than 0.7, and were statistically acceptable85. Convergent validity was evaluated by outer loadings and the average variance extraction (AVE) values. Based on the results, the factor loadings of the measurement items were all greater when compared with the threshold of 0.786. The AVE values of all structures were greater than 0.5, within the range from 0.576 to 0.674. Therefore, the five first-order constructs engaged in this model were considered to exhibit a high level of convergent validity.

Table 3 Assessment of the first-order factor model (N = 345).
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Finally, using Fornell-Larcker criterion, discriminant validity was evaluated by the square root of AVE. Table 4 presents that the square root of AVE for each structure is higher than its correlation values with other factors. The above discussion indicates that reliability, convergence, and discriminant validity all meet the evaluation criteria, which can support all first-order measurement models.

Table 4 Fornell-Larcker criterion of the first-order factor model.
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Measurement model evaluation: second-order factor model

A hierarchical component model was adopted for verifying the higher-order latent constructs in PLS-SEM87. The higher-order structure PDRQs was consisted of three lower-order components, namely Away, Compatibility, and Extent. The path coefficients of the three dimensions of PDRQs were all above 0.7 and were significant at the level of p < 0.01, and the R2 of each dimension was shown to be greater than the recommended value of 0.5. In addition, the AVE and CR of PDRQs as a second-order construct were 0.753 and 0.902, separately (Table 5), both of which exceed the critical standard. Based on the obtained results, PDRQs, as a second-order construct, is found to be reliable and effective.

Table 5 Assessment of the second-order factor model.
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Structural model evaluation

Before hypothesis testing, a variance inflation factor (VIF) test was conducted in the structural model to avoid estimation bias resulted from collinearity of independent variables. Based on the findings, the VIF values of all variables were < 5. This result conforms to Park et al.88.

PLS-SEM estimated the predictive ability of the entire structural equation model, with the value of R2 being 45.4%, indicating that the model has a good level of explanation75. The Q2 values of all endogenous latent variables were greater than 0, indicating that the model has good predictive effects89. The f2 values of all significant impact paths in the model were higher than 0.02, which met the acceptable standard90.

Evaluation of direct effects

Based on the bootstrapping program in Smart-PLS 3.0 software, the significance of each path coefficient was examined. According to Table 6; Fig. 3, among the five hypotheses, four hypotheses were supported at the 1% significance level. To be specific, PDRQs had a positive and significant impact on EWB and EDI (β = 0.702, p < 0.01; β = 0.726, p < 0.01); PDRQs did not make a positive and significant effect on WTP (p > 0.05); EWB and EDI also had positive and significant impacts on WTP (β = 0.382, p < 0.01; β = 0.263, p < 0.01).

Table 6 Results of direct effects.
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Fig. 3
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Structural equation modelling results.

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Evaluation of indirect relationships

The present work used the bootstrapping method to test the mediating effects of EDI and EWB between PDRQs and WTP for environmental protection. If the bootstrapped indirect effects are of significance with a t-value > 1.96 at the significant level of 5%, and the confidence interval does not contain the value of zero, mediating effect will be supported91. In accordance with Table 7, all two indirect paths from PDRQs to WTP for environmental protection were of significance, with t > 1.96 and p < 0.01. The two variables (EWB and EDI) completely mediated the causal relationship between PDRQS and WTP.

Table 7 Results of indirect effects.
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Discussion

Selecting Hulunbuir Grassland, the most famous grassland ecotourism destination in China, as the research site, this study introduced RPM, and constructed a theoretical model consisting of PDRQs, EWB, EDI, and WTP to investigate how PDRQs, EWB, and EDI affect tourists’ WTP for environmental protection.

Discussion

Firstly, This study identifies that PDRQs in grassland tourism destinations comprises three dimensions: extent, compatibility, and being away. This finding diverges from the research by Chen et al.16. Chen et al.16 and Qiu et al.22 have previously established that PDRQ encompasses five dimensions—compatibility, extension, mentallyway, physically away and fascination—in the contexts of industrial, hot spring, and coastal tourism destinations. However, the results of this study indicate that the scale based on these five factors is not applicable to grassland tourism destinations.

Instead, grassland tourism destinations offer a restorative environment through the three dimensions of being away, compatibility, and extent. The visual impact of the grassland’s natural landscape and its unique nomadic culture creates an environment that is markedly different from urban settings, providing tourists with an immersive atmosphere that allows them to escape from their daily routines. The vastness of the grassland not only forms an emotional connection with visitors through its distinctive natural and cultural landscapes but also offers the spatial compatibility needed to engage in a variety of tourism activities.

Secondly, this study reveals that there is no direct significant effect of PDRQs on WTP for environmental protection. This finding diverges from previous research14,22, which demonstrated a positive direct impact of PDRQs on tourists’ environmentally responsible behavior. The possible reason for this difference is that WTP is a payment behavior that requires more money, and WTP for environmental protection is more difficult to trigger than environmentally responsible behavior. PDRQs can hardly stimulate tourists’ WTP directly, and need more cognitive and emotional psychological processes to be aroused and involved. In other words, tourists’ WTP is activated only when the external environment triggers intrinsic psychological effects and establishes a connection between psychology and the surroundings.

EWB emerged as a crucial predictor of tourists’ WTP for environmental protection. EWB is a meaningful spiritual experience, in which tourists achieve profound self-actualization in the restorative environment of ecotourism destinations, bringing them a sense of satisfaction and value, creating an emotional bond with the environment, enhancing their resonance and connection with the destination, and increasing their reflection on the meaning of life. These motivations ultimately lead to their WTP47. Moreover, This also validates the research findings of affective heuristics theorists92, Slovic et al.93 argued that when an object elicits positive emotions in people, they will consider the impact of their actions on the object when taking actions, and tend to take actions that are beneficial to protecting the object.

EDI made a significant and positive effect on tourists’ WTP for environmental protection, indicating that once tourists perceive the EDI, they formed a cognitive and emotional connection with the ecotourism destination, which promoted their WTP for environmental protection. This is consistent with previous research results, which show that tourists are more likely to take positive actions for destinations or tourism products that have a green, sustainable, and ecological image94,95. For instance, Can et al.68 demonstrated that tourists are more inclined to pay a premium for destinations with a Blue Flag image. This is because the EDI represents a commitment to sustainability and environmental protection, which can enhance tourists’ awareness of the environmental and socio-cultural value of the destination, and increase tourists’ WTP for environmental protection.

Thirdly, PDRQs had a significant positive effect on EWB. PDRQs encompass three attributes, namely extent, compatibility, and away, which indicate that once tourists perceive the restorative properties of the destination environment, such as scope, compatibility, and away, they will rejuvenate their self-awareness, generate a sense of value and satisfaction, and promote well-being. This supports the perspective put forth by Kaplan & Kaplan24 that restorative natural environments positively affect human well-being. Furthermore, this perspective conforms to multiple research studies14,22,96. Unlike previous studies, this research reveals that grassland tourism destinations facilitate tourists’ spiritual self-repair through the dimensions of extent, compatibility, and being away. This process ultimately fosters a sense of value and satisfaction among visitors.

PDRQs had a significant positive effect on EDI, which implied that the restorative attributes of extent, compatibility, and away contribute to the establishment of EDI. Extent refers to the richness and continuity of the environment content, which ensures that people can integrate into the environment and carry out relevant activities. Pals et al.97 pointed out that extent emphasizes the basic perceptual characteristics of the environment (external), aligning with the cognitive image of the diversity and breadth of the ecotourism destination resources. Compatibility and away highlight the subjective feelings of interaction between individuals and the environment (internal), which help to foster positive emotions for tourists towards the ecotourism destination. These external characteristics and subjective feelings collectively promote the formation of EDI.

Fourthly, the current work verified the full mediating role of EWB and EDI between PDRQs and WTP for environmental protection. That is, tourists who experience spiritual satisfaction and self-actualization after participating in PDRQs, and who perceive the image of the ecotourism destination, are likely to exhibit higher WTP. This finding demonstrates the adaptability of RPM in predicting tourists’ WTP and further underscores the criticality of the effectiveness parameters. EWB and EDI (effectiveness) as mediators between PDRQs (model construction) and WTP for environmental protection (meaningful action) provide a deeper comprehension of the human-environment interaction at the destination. This finding also validated the research findings of Qiu et al.22, who observed that EWB mediates the correlation between PDRQs and tourists’ responsible behavior.

Theoretical implications

First, the present study expands the application scope of the RPM framework in the field of environmental psychology. It applied it to the study of WTP for environmental protection in ecotourism destinations. Previous studies primarily relied on traditional theories including TPB and VBN to investigate tourists’ WTP for environmental protection, while this paper applied RPM for the first time to examine the correlation between PDRQs, EWB, EDI, and WTP. This study enriched the research field of RPM in the effectiveness stage by proposing and testing the intrinsic and extrinsic effectiveness of PDRQs, and offered a fresh theoretical perspective for environmental psychology on how place experiences influence the intrinsic and extrinsic psychological connection of tourists in ecotourism destinations.

Second, the second theoretical contribution of the current study refers to that it provided clarity regarding the theoretical relationship between PDRQs, EWB, EDI, and WTP of tourists in ecotourism destinations, focusing on grassland tourism destinations as a case. Significantly, this study revealed, for the first time, the triggering mechanism of tourists’ WTP from the destination perspective, and verified the causal relationship between the three antecedent variables (PDRQs, EWB, and EDI) and the outcome variable (WTP). The results demonstrates that PDRQs did not make a vital effect on WTP for environmental protection, but made a positive and significant effect on tourists’ EWB and EDI. Moreover, EWB and EDI were found to positively and significantly influence tourists’ WTP for environmental protection. Consequently, this study further enriched the related research on PDRQs, EWB, and EDI.

The third theoretical contribution is that it revealed for the first time the full mediating role of EWB and EDI between PDRQs and WTP for environmental protection, and verified the mechanism of PDRQs’ influence on WTP. In previous studies, there was hardly any literature that discussed the mediating role of EWB and EDI between PDRQs and WTP. The findings from the structural equation modeling (SEM) revealed that EWB and EDI played a full mediating role between PDRQs and WTP, forming the PDRQs→EWB→WTP and PDRQs→EDI→WTP impact paths. Consequently, this study confirmed the important theoretical position of EDI and WTP in the relationship between PDRQs and WTP, and provided a new theoretical perspective for future WTP for environmental protection research.

Practical implications

In addition, this study offers new insights for securing additional funding for ecotourism destinations and solving the problems of development and conservation, and has the following practical implications.

Firstly, managers can enhance tourists’ WTP by focusing on three key areas: improving PDRQs, tourists’EWB, and EDI.

Managers can optimize Hulunbuir’s restorative experience environment by addressing three critical dimensions: being away, compatibility, and extent. From the perspective of creating a sense of distance from everyday life, managers should craft an immersive environment that is distinct from tourists’ daily routines. By leveraging the region’s pristine ecological landscapes, unique nomadic culture, and the vast expanse of the grasslands, they can build a multi-sensory experience that engages vision, hearing, and smell. This environment should not only provide physical separation from the mundane but also enable tourists to recalibrate their perceptual systems. Through this reset, visitors can establish an entirely new cognitive framework within the grassland’s unique temporal and spatial context. Ultimately, this transformation allows tourists to move beyond mere “physical escape” and achieve a profound “spiritual migration.”

From the perspective of fostering compatibility, managers should strive to create a profound emotional bond between the Hulunbuir Grassland and its tourists, nurturing a deep sense of identity and belonging among tourists. To achieve this, they should develop immersive tourism activities that enable guests to actively engage with the local culture and environment. These activities may include traditional handicraft workshops, hands-on grazing experiences, and participation in ecological conservation projects, allowing tourists to feel like integral members of the grassland community. Moreover, managers should prioritize maintaining long-term connections with tourists. By leveraging online communities, inviting them to regular events, and sending culturally relevant souvenirs or updates, they can reinforce the sense of belonging that tourists feel towards the Hulunbuir Grassland.

From the perspective of extent, managers should design a diverse range of tourism activities that align with the expansive expanse of the Hulunbuir Grassland. This will enable tourists to fully immerse themselves in the vastness and sense of boundless space that the grassland offers. By placing observation decks and panoramic viewpoints, tourists’ visual and spatial perception will be significantly enhanced. Additionally, low-density, long-distance activities such as horse riding, hiking, and self-driving tours will be organized. These activities allow tourists to physically traverse the landscape, experiencing the extension of distance and space as they move through the grassland.

Next, EWB is a key mediator between PDRQs and WTP for environmental protection. Managers should rely on the excellent ecological tourism resources and environment of Hulunbuir, and cultivate high-end ecological tourism offerings, such as nature education, ecological research, popular science investigation, outdoor adventure, grassland vacation, and more. Managers should incorporate the principles of ecological protection and sustainable development into eco-tourism offerings. They should guide tourists to engage in ecological restoration projects and educate them on how to safeguard local flora and fauna. By doing so, tourists can truly appreciate the positive impact of their spending on the protection of the grassland ecosystem, benefiting both herders and the grasslands. This approach will also fulfill tourists’ higher-level needs for meaningful and responsible travel experiences.

Finally, Hulunbuir’s EDI is another important mediator between PDRQs and WTP for environmental protection. Therefore, managers should do a good job of disseminating Hulunbuir’s EDI. They should strengthen the strategic collaborations with mainstream media and key online media, while highlighting the role of new media like TikTok, Kuaishou, WeChat, Weibo, Xiaohongshu, and more, and encourage netizens to create content around Hulunbuir tourism through competitions, contests, and other ways, and establish a content production and marketing mechanism with multiple participants.

Limitations and future research

Despite the theoretical and practical significance, there are still limitations requiring further studies. Firstly, the cross-sectional design restricts the in-depth understanding of the longitudinal outcomes of PDRQs. Moreover, future researches should explore the duration of various impacts of PDRQs on tourists, and increase the research results by continuously exploring tourists’ perceptions of PDRQs and the behaviors they trigger. Secondly, this study solely examined the direct and indirect effects of PDRQs without testing the moderating effects. As a result, future studies need to propose moderators to enhance or lower the suggested effects of the proposed model. Thirdly, Hulunbuir is an ecotourism destination with grassland, forest, wetland and other landscape features as the main characteristics. The conclusions of this study are applicable to such ecotourism destinations, but the generalizability to other types of ecotourism destinations remains to be verified.

Conclusion

The primary conclusions of this study are summarized as follows: Firstly, the study identifies that PDRQs in grassland tourism destinations encompass three key dimensions: extent, compatibility, and being away. Secondly, the study elucidates the influence mechanism of PDRQs on WTP. It is demonstrated that PDRQs do not exert a direct and significant impact on WTP for environmental protection. Instead, the study confirms that EWB and EDI play a complete mediating role between PDRQs and tourists’ WTP for environmental protection. Thirdly, the study offers practical implications for enhancing tourists’ WTP by improving PDRQs, as well as by enhancing tourists’ EWB and EDI.