Application of the Travel Cost Method to Estimate the Economic Value of Brasília National Park

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study applied the travel cost method, a widely used and effective environmental assessment method, to estimate the economic value of Brasília National Park. The study successfully quantified tourists' price sensitivity through regression analysis and questionnaire surveys and found that travel costs significantly impact park demand. The study's results indicate that a 1% increase in travel costs leads to a 4.1% decrease in park visitation, suggesting that park visitors are susceptible to cost changes.

In addition, the study estimates the annual economic value of Brasília National Park at approximately US$25 million (approximately R$140 million), a figure that will be of great reference value to policymakers and management agencies. This result highlights the park's economic contribution to the local community and supports the development of new financial mechanisms to ensure the sustainable operation of the park.

However, there may still be room for improvement in research. For example, future research could include more variables to explore further factors that influence tourists' decisions, such as tourists' socioeconomic background, alternative recreational options, or the environmental qualities of the park. In addition, analysis of data across multiple years may provide more robust results and help understand long-term trends in park demand.

Overall, this paper provides substantial empirical evidence for environmental economics, which can help strengthen the financial viability assessment of nature reserves and provide more specific recommendations for policymaking.

Please provide a more in-depth discussion and comparison of the models in Equations 6, 7, 8, and 9.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Attached,  you  can  find  my  comments  !

Comments for author File: Comments.pdf

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors The document presents information and methodology for calculating the economic value of recreational use of Brasília National Park based on travel costs. The document could be improved; below are some suggestions for consideration. a) The document presents information and references related studies in other parks. Could slightly more recent references be included? b) The limitations of the cited works for comparison could be included. c) It would be important to include a map that illustrates and contextualizes the park's location. Furthermore, the use of GIS is mentioned for a methodological step without presenting any map. Distance calculations are also mentioned, but there is no graphic evidence to aid understanding. d) A sensitivity analysis or multivariate regression could be included to reinforce the results, or even include variables such as age; although their lack of significance is mentioned. e) Could considering only residents of the Federal District lead to an underestimation of the value? f) Review the overall wording. Comments on the Quality of English Language

English writing could be improved

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

I read with great interest the study entitled “Application of the trip cost method to estimate the economic value of Brasilia National Park”.  

The study's goals are to calculate the economic value of using the Brasília National Park for recreation, confirm that the geographical approach of the travel cost method applies to the administrative divisions of the Federal District, and assess how sensitive park visitors are to changes in travel costs. Unfortunately, I had a lot of difficulties reading the manuscript and I understood that it has no scientific novelty. Generally, the manuscript has some serious problems and must be repaired before publication. It needs some significant improvement. Some suggestions are as follows:

- Firstly, as a research paper, this paper needs to critically assess work previously carried out in the field. Although this has been done to a limited extent in the introduction, some key points are missed. Perhaps the most significant articles in the research field, a similar worldwide research, etc.

- The theme of the work is relevant, but the article needs to be improved in the scientific context.

- It is impossible for a scientific and research paper to be complete without at least one image explaining how the test area is displayed, a visually presented research process, or the presentation of the research findings using a variety of graphic attachments, diagrams, or graphs.

- All statistical tests must be shown visually in order to enhance the content and make it better.

- The list of literature cited is quite short, and multiple pertinent sources must be consulted for a scientific article.

In light of the foregoing, I suggest rejecting the article and providing the authors the chance to substantially improve it.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors The authors made improvements to the document based on the reviewers' comments. The document has a better structure, making it easier to read and interpret. Figure 4 could be improved; the text on the axes should be larger.

Author Response

Figure 4 could be improved by increasing the size of the text on the axes.

Authors’ response - Improved Figure 4 in the “3.2. Economic value of recreational use of the National Park of Brasília”

To describe the content succinctly and contextualize it in relation to both previous and current theoretical frameworks, as well as to the empirical research (if applicable) on the topic.

• Authors’ response - Included paragraph “16” in the “2.4. Research design” section:

“Finally, the recreational use value of Brasília National Park (PNB) was estimated by multiplying the aggregate consumer surplus by the number of visits to the park in 2019, a total of 251,521 visits, according to the park administration.

(13)

Where: = economic value of PNB; = aggregate consumer surplus; = 251,521 visits”

Authors’ response - Included paragraph “24” to “26” in the “3.2. Economic value of recreational use of the National Park of Brasília” section:

“The economic value of environmental resources stems from all their attributes, whether or not they are associated with actual use. The Total Economic Value (TEV) of a resource comprises use values, composed of direct use value and indirect use value, and non-use values, composed of option value, bequest value, and existence value.

Regarding use values, the Direct Use Value (DUV) refers to the immediate, tangible benefits obtained from the resource through activities like extraction, visitation, or other forms of direct consumption or production. In contrast, the Indirect Use Value (IUV) arises from the ecosystem services the resource provides, such as the protection of soil through forest conservation.

Regarding non-use values, the Existence Value (EV) reflects the satisfaction individuals derive from simply knowing that a natural resource or species exists, regardless of any current or future use. This value is often rooted in cultural, ethical, moral, or altruistic beliefs regarding the importance of preserving nature. The Option Value (OV) represents the value placed on preserving the possibility of using the resource in the future, particularly in contexts where its availability may be uncertain or threatened. Finally, the Bequest Value captures the satisfaction individuals feel from ensuring the conservation of environmental resources for the benefit of future generations.”

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

I appreciate the authors' attempts to implement my recommendations. The paper has, in my opinion, been enhanced. The authors provide a convincing rebuttal to the reviewers.

These factors lead me to recommend accepting the manuscript as is.

Author Response

1. Conclusions grounded in the results presented in the article or supported by secondary literature.

• Authors’ response – It incorporated the main quantitative results and statistical evidence, reinforcing the connection between the analyzed data and the conclusions. Included paragraph “2” to “7” in the “4. Conclusion” section:

“Using the TC method, the estimated economic value of the park’s recreational use is approximately USD 25 million per year, with an average consumer surplus of USD 2.58 per visit. This figure aligns with the park's current ticket price (USD 2.54), suggesting a pricing policy that is consistent with profit maximization without significantly reducing visitation. Furthermore, the hypothesis that the consumer surplus per visit exceeds the current entrance fee was supported.

The chosen econometric model (Log-Log) demonstrated strong statistical validity (R² = 95.65%), normal residual distribution, and absence of autocorrelation and heteroscedasticity, confirming the robustness of the findings.

The estimated price elasticity of demand was -4.1, indicating elastic demand: a 1% increase in travel cost leads to a 4.1% decrease in visitation rates. Although the study claims that PNB has few competitors due to its privileged location, favorable climate, and an apparent lack of alternatives that combine tourism and sports activities, the results suggest otherwise. The demand for visits to the PNB was found to be elastic, indicating that visitors are sensitive to changes in price. This type of demand typically implies the existence of nearby substitute goods, such as other parks, green areas, and recreational options within the Federal District. Therefore, even though the park may have unique attributes, the data show that increases in costs significantly reduce visitation frequency, challenging the notion that the PNB faces limited competition.

This behavior highlights the importance of considering access costs in public policy planning. The analysis also revealed that visitation rates decrease as the distance from the origin increases, with visitors from the closest zones showing the highest visitation frequencies.

One of the main limitations of this study is inherent to the TC method itself, which allows for the estimation of the economic value of direct use only, without capturing non-use values (option value; bequest value; existence value) or indirect use values, which are essential components of the total economic value (TEV) of an environmental resource. Additionally, the estimates presented did not account for the benefits generated by visitors who reside outside the Federal District, which may have led to an underestimation of the consumer surplus. Another limitation lies in the difficulty of comparing the results with those of other studies, due to the particularities of each recreational site, which differ in terms of visitor profiles, income levels, local currencies, education levels, and proximity to the recreational area. Nevertheless, the findings of this research proved to be consistent with those of other referenced studies that also applied the TC method, reinforcing the reliability of the results.

Although the study focused solely on residents of the Federal District, the estimated values confirm the park’s importance as an urban ecological and recreational asset. Further studies are recommended, including visitors from other regions, incorporating meteorological variables (temperature, relative humidity, and precipitation) that also influence visitation patt, and complementary methods such as Contingent Valuation, to estimate non-use values indirect use values, thus capturing the TEV of the conservation unit. Also to allow for the comparability of results and the consolidation of the methodology.”

2. To describe the content succinctly and contextualize it in relation to both previous and current theoretical frameworks, as well as to the empirical research (if applicable) on the topic.

• Authors’ response - Included paragraph “16” in the “2.4. Research design” section:

“Finally, the recreational use value of Brasília National Park (PNB) was estimated by multiplying the aggregate consumer surplus by the number of visits to the park in 2019, a total of 251,521 visits, according to the park administration.

 

 (13)

Where: = economic value of PNB; = aggregate consumer surplus; = 251,521 visits”

 

• Authors’ response - Included paragraph “24” to “26” in the “3.2. Economic value of recreational use of the National Park of Brasília” section:

“The economic value of environmental resources stems from all their attributes, whether or not they are associated with actual use. The Total Economic Value (TEV) of a resource comprises use values, composed of direct use value and indirect use value, and non-use values, composed of option value, bequest value, and existence value.

Regarding use values, the Direct Use Value (DUV) refers to the immediate, tangible benefits obtained from the resource through activities like extraction, visitation, or other forms of direct consumption or production. In contrast, the Indirect Use Value (IUV) arises from the ecosystem services the resource provides, such as the protection of soil through forest conservation.

Regarding non-use values, the Existence Value (EV) reflects the satisfaction individuals derive from simply knowing that a natural resource or species exists, regardless of any current or future use. This value is often rooted in cultural, ethical, moral, or altruistic beliefs regarding the importance of preserving nature. The Option Value (OV) represents the value placed on preserving the possibility of using the resource in the future, particularly in contexts where its availability may be uncertain or threatened. Finally, the Bequest Value captures the satisfaction individuals feel from ensuring the conservation of environmental resources for the benefit of future generations.”

3. Clearly state the research design, questions, hypotheses and methods.

• Authors’ response - Included paragraph “10” to “13” in the “1. Introduction” section:

“This study employs a quantitative, non-experimental research design grounded in environmental economics, specifically using the Travel Cost method to estimate the recreational use value of Brasília National Park (PNB). The approach includes a structured survey to collect primary data from park visitors and an econometric analysis to estimate consumer surplus and travel demand elasticity. The TC method is an appropriate tool for valuing the direct-use benefits provided by natural resources, as it captures visitors revealed preferences and allows for the estimation of a monetary value based on their willingness to pay for access to the environmental goods and services offered by Brasília National Park. Therefore, the application of the TC method to Brasília National Park will enable an estimation of the recreational demand function and the annual economic value associated with its use, providing empirical evidence to support public policies for urban conservation management.

Thus, the research questions are:

1. What is the direct use value of Brasília National Park for its visitors?
2. How does travel cost influence the frequency of visits to the park?

• Does the current entrance fee reflect the recreational value perceived by visitors?

1. Is the price elasticity of demand for visits to Brasília National Park elastic or inelastic?

So, the hypotheses to be tested are:

1. The coefficient for travel cost is expected to be negative and statistically significant, reflecting its inverse relationship with visitation rates, meaning the frequency of visits to PNB decreases as the travel cost increases.
2. The estimated consumer surplus per visit exceeds the current entrance fee, indicating underpricing.

• The price elasticity of demand for visits to Brasília National Park will be inelastic, reflecting the unique importance of the park to its visitors and the lack of close substitutes. As a result, changes in travel cost will lead to relatively smaller changes in the quantity of visits demanded.

Data was collected through face-to-face surveys conducted with a sample of 300 visitors at the entrance of PNB. The questionnaire included sections on demographic characteristics, number of visits and travel expenses. The TC method was applied using a Log-Log regression model, with visitation rate as the dependent variable and travel cost, income and age as independent variables. Diagnostic tests (e.g., Shapiro-Wilk, Breusch-Pagan, Durbin-Watson) were used to validate the model’s assumptions, ensuring the robustness and reliability of the results.”

 

• Authors’ response - Included paragraph “15” to “17” in the “3.2. Economic value of recreational use of the National Park of Brasília” section:

“The independent variable tested in the model, average travel costs per zone (CVm), was statistically significant and had the negative expected sign, confirming the hypothesis of being statistically significant and that the frequency of visits to PNB decreases as the travel cost increases.”

“This finding contradicts the assumption that the PNB has few substitutes and reinforces the idea that visitors respond sensitively to cost changes, so the hypothesis that demand would be inelastic was not supported.”

“This supports the hypothesis that visitors derive more value from the park experience than they pay for, indicating a potential for revenue optimization without harming visitation levels.”

 

4. Clearly present the results.

• Authors’ response - Included paragraph “7” in the “3.1. Sample Description” section:

“In summary, the average visitor to Brasília National Park (PNB) is male, approximately 30 years old, and possesses a high level of education and a family income of around five minimum wages. These findings are consistent with previous studies on ecotourism and urban park visitation.”

• Authors’ response - Included paragraph “15” to “18” in the “3.2. Economic value of recreational use of the National Park of Brasília” section:

“In summary, the econometric model employed was a log-log regression, which demonstrated a strong statistical fit (R² = 95.65%). The log-log model demonstrated the best statistical and econometric performance among the models evaluated, being robust and suitable for analyzing the demand for visits to PNB. The diagnostic tests confirmed the model’s adequacy: the residuals were normally distributed (Shapiro-Wilk = 0.93; p = 0.60), homoscedastic (Breusch-Pagan = 0.07; p = 0.79), and showed no autocorrelation (Durbin-Watson = 2.50; p = 0.55). Furthermore, the model was statistically significant overall, as indicated by the F-test (F = 87.98; p < 0.01). The independent variable tested in the model, average travel costs per zone (CVm), was statistically significant and had the negative expected sign, confirming the hypothesis of being statistically significant and that the frequency of visits to PNB decreases as the travel cost increases.

The log-log model allows the coefficients to be interpreted directly as elasticities. The price elasticity of demand was estimated at –4.1, suggesting a highly elastic demand: a 1% increase in travel cost leads to a 4.1% decrease in visitation frequency. This finding contradicts the assumption that the PNB has few substitutes and reinforces the idea that visitors respond sensitively to cost changes, so the hypothesis that demand would be inelastic was not supported.

Using the TC method, the estimated average consumer surplus per visit was USD 2.58, which is slightly above the current entrance fee of USD 2.54. This supports the hypothesis that visitors derive more value from the park experience than they pay for, indicating a potential for revenue optimization without harming visitation levels.

Finally, the total recreational use value of the park was estimated at USD 25 million per year, based on the aggregate consumer surplus multiplied by the number of visits to Brasília National Park in 2019 (251,521 visits). This substantial value highlights the importance of the park not only as an environmental asset but also as a significant contributor to social welfare and urban quality of life.”

 

Author Response File: Author Response.pdf