1. Introduction
Ecosystem services (ES) refer to the benefits to human society obtained directly or indirectly from nature [
1]. ES are fundamental to sustaining life and promoting human well-being, providing critical benefits, such as air and water purification, climate regulation, and biodiversity support [
1,
2]. Natural resources can enhance human well-being; however, some human activities can also affect the natural environment [
3]. This interaction is particularly pronounced in protected areas such as national parks, which serve as key reservoirs of biodiversity and natural habitats. Palomo et al. [
4] have demonstrated that national parks and their buffer zones offer a diverse array of ecosystem services that benefit the surrounding lands. These areas support an ecological balance and offer recreational, cultural, and spiritual benefits to society.
Japan is renowned for its diverse and picturesque natural landscapes and hosts a network of national parks that are pivotal to its ecological conservation efforts. Japan’s national park system was established in 1931 through the passage of the National Park Law. Japan’s national parks are “regional” (
chiikisei) parks that can be designated by setting areas regardless of land ownership, and within the designated areas, various actions that alter the natural environment are regulated as actions that require permission or notification [
5]. In addition, various facilities have been developed as places to interact with nature. The Ministry of the Environment (MoE) has set up branch offices to handle various management tasks, including issuing permits and licenses. These parks play a dual role in preserving biodiversity and supporting substantial tourism. The ecological value of Japan’s national parks is immense, as they provide critical ecosystem services that contribute to environmental stability and resilience.
Economically, these parks are significant tourism destinations that attract millions of visitors annually and contribute to local and national economies. The Japanese government is working on the “Tourism Vision to Support Japan’s Future,” which aims to increase the number of foreign visitors to Japan to 60 million by 2030. National parks are positioned as one of the pillars of the “Tourism Vision to Support Japan’s Future,” which was compiled by the government in March 2016, and the “Project to Fully Enjoy National Parks” has been promoted (
https://www.env.go.jp/en/nature/enjoy-project/index.html, accessed on 15 January 2025). This project targeted the branding of Japan’s national parks as world-class national parks and initially focused on eight selected national parks (the “Priority Eight Parks”) to implement pioneering and intensive initiatives. Nevertheless, an increase in visitor numbers can exacerbate ecological pressures, leading to issues such as increased waste in the community, habitat destruction, pollution, and a decline in biodiversity, ultimately impacting the provision of ecosystem services [
6,
7].
Quantifying ecosystem service value (ESV) and monitoring its changes are crucial for assessing the effectiveness of conservation efforts [
8]. One of the efficient methods for this purpose is the benefit transfer method (BTM) is an efficient method for this purpose. The BTM is used to estimate the value of ES in one location or context by applying valuation data from a similar location or study. In a pioneering valuation study, Costanza et al. [
8] combined the unit area values of 17 ecosystem services across 16 ecosystem types with global distribution data to first attempt to estimate the global value of ecosystem services and natural capital. De Groot et al. [
9] updated the 1997 valuation by incorporating data from the Economics of Ecosystems and Biodiversity (TEEB) Initiative. Costanza et al. [
10] estimated losses and gains in ecosystem services from 1997 to 2011. Therefore, these studies established favorable conditions for utilizing BTM to assess ESV. Changes in land use and land cover (LULC), driven by various factors, significantly influence ecosystem services [
11]. Based on these foundations, the value coefficients and adjusted coefficients combined with LULC change analysis are widely used in the value transfer method when estimating the ESV [
12,
13,
14,
15].
Remote sensing has been widely used in LULC classification, enabling the analysis of land-cover changes over time [
16,
17]. Previous studies have employed remote sensing to map LULC classifications at the national park scale, providing evidence for further analysis of ESV changes in these areas [
18,
19,
20,
21].
Some studies have demonstrated how tourism can alter LULC and affect landscape and ecosystem functions. Research has indicated that the rise in tourism in Nepal’s national parks may be linked to observed LULC changes, such as the expansion of built-up areas and a decline in forest cover [
22]. A study conducted in Bali found that tourism growth drove changes in LULC, and an increase in visitors encouraged the construction of tourism-related buildings [
23]. Vijay et al. [
24] found that areas with rapid tourism growth also experienced a rapid expansion of built-up land, confirming the impact of tourism pressure on LULC. Despite advancements in assessing ESV dynamics based on LULC changes, a gap still exists in integrating the tourism context with ESV change analysis, particularly from a policy-driven perspective. As the “Project to Fully Enjoy National Parks” has been implemented in selected national parks in Japan, these policy-driven tourism initiatives may have influenced land use and, in turn, affected ecosystem services. However, current research frequently neglects the intersection of policy-driven tourism initiatives and environmental conservation strategies for ecosystem services. Addressing this gap is vital to developing comprehensive strategies that balance ecological preservation with socioeconomic development in Japan’s national parks and similar environments.
This interdisciplinary study aims to bridge these gaps by examining the interplay between tourism development, LULC changes, and ecosystem service values, providing a nuanced understanding of the socio-ecological dynamics within Japan’s national parks. Specifically, the research objectives of this study are: first, to map the LULC of Akan-Mashu National Park (one of the “Priority Eight Parks”) from 2014 to 2023 through remote sensing technology; second, to calculate the ESV for each year from 2014 to 2023 using the benefit transfer method; third, to explore the changes in LULC and ESV of Akan-Mashu National Park from the perspective of promoting tourism development in combination with the qualitative analysis of tourism planning policy documents; and fourth, to propose future national parks management recommendations based on the research results. As a baseline study, our research aims to verify the effectiveness of the policy and provide a scientific basis for the long-term monitoring and policy optimization of protected areas such as national parks.
4. Discussion
4.1. Changes of LULC
The LULC results of this study revealed that the land-use type in the Akan-Mashu NP was dominated by forests, followed by water bodies and grasslands. Human activities engaged in land-use types: cultivated and built-up areas cover only a small portion of the study area. This result is consistent with the features of the NP, which has a magnificent landscape that weaves volcanoes, forests, and lakes together. Although the percent annual change of forests decreased from 2014 to 2023, the absolute change was 0.06%, indicating almost no significant changes. Similar to forests, changes in water bodies, grasslands, and bare land were slow. The percentage of annual changes in built-up areas (2.89%) and cultivated areas (1.20%) was relatively higher than that of the other land-use types. The LULC transition ration matrix reflects the mutual conversion between these two land-use types. As of 2020, the management department has implemented numerous measures to attract tourists, as summarized in
Section 3.3. Among these measures, projects increase the construction area by opening and building new walking trails, viewing platforms, and parking lots (
Table 10). We believe that these initiatives to promote tourism are one of the reasons for the increase in built-up areas. On the other hand, previous studies have indicated a marked increase in abandoned farmland in Japan due to the substantial decline and aging of its rural population [
37,
38]. Our research showed that cultivated land within national parks has developed steadily over the past decade, with a steady increase from 2014 to 2023. This result may be because our study period was in the last decade, and the coverage area was not large enough, which does not reflect the more significant phenomenon of farmland abandonment. Additionally, a study has found that the farmland abandonment rate in Hokkaido is lower than in other regions of Japan [
39].
As summarized in
Table 1, most of the zoning in this area is classified as special zoning, which has several restrictions and regulations. Our findings regarding changes in LULC indicate that land use has not shifted significantly over the past decade, demonstrating the success of protection and management strategies.
4.2. Changes of ESV
Our results show that different land-use types contribute to different ESV. Although water bodies account for only approximately 12% of the total area of the national park, they provide more than 70% of the ESV, which shows the importance of this land-use type in the overall ecosystem service. In particular, the three major lakes, Lake Akan, Lake Mashu, and Lake Kussharo, not only have supporting services and regulating services and provide habitat functions for plants and animals but are also important scenic spots. According to the policy documents of the management department, there are artificial facilities, such as observation platforms and campsites, around the lakes. Therefore, we believe that the areas around the three major lakes need to focus on monitoring ecological changes and tourism pressure. The coefficient table (
Table 4) shows that cultivated areas can provide objective regulation and cultural service values. However, a study predicts that farmland abandonment is likely to become a widespread issue across Japan in the future [
38]. This requires management departments and local town governments to make efforts to balance local agricultural development with national park management.
From the time-series results of the ESV, the changes in the past decade have been very slow, and the overall ESV has increased by USD 13.85 million. Our research results reflect that management planning is very effective, and the plan to promote the development of tourism has not brought too much pressure and impact on the local ecological environment. Although our results showed minor changes in ESV, they do not imply that conservation efforts should be overlooked. Instead, a stable ecological state should promote the ongoing implementation of effective policies to sustain existing ecological service values.
4.3. Management Recommendations
Based on the main findings of this study, we propose several management recommendations for balancing ecological conservation and tourism development in national parks. We hope that these recommendations will not only apply to the subjects of this study—Japan’s national parks—but will also provide a reference for managing similar environments worldwide. First, our results suggest that the Japanese national park zoning management system may have contributed to the observed stability in land use and ESV over the past decade. Zoning management systems should continue to be strictly followed in the future to ensure the ecological conservation of national parks. This recommendation is applicable globally, especially in developing countries such as China, which has recently begun to establish national parks. Second, we suggest that abandoned vacant lands or buildings in Akan-Mashu National Park be demolished and replaced with new tourism facilities. This approach would not occupy additional construction land and could enhance the area’s appeal and tourism experiences for visitors. Third, by identifying the value share of different types of ecosystem services, we can provide a reference for future tourism planning goals of national parks. Although we acknowledge that the current ESVD may lead to an underestimation of the value that certain ecosystem services can provide, we believe that applying a consistent methodology across different national parks allows us to observe changes in the proportional contribution of different ecosystem types to the overall value. Based on these variations, this analysis can serve as a reference for planning future tourism strategies. For instance, when cultural services have the highest proportion, management can use the local culture as the main feature to attract visitors. Finally, we will propose possible directions for future visitor management. Focusing on the carrying capacity of the national park is one possible approach [
40]. For instance, setting seasonal or annual visitor limits could help regulate tourism impact. In addition to fixed numerical limits, there are resilience-based theories such as the Limits of Acceptable Change (LAC), a framework that has been widely applied in the management of national parks [
41,
42]. Unlike carrying capacity, LAC assumes that environmental changes are inevitable, emphasizing the importance of identifying acceptable levels of change and developing management. We believe that these theories and approaches could be applied to the future visitor management of this national park. Although visitor numbers have remained relatively stable over the past decade, there is significant potential for growth in the future. Therefore, it is essential to establish appropriate strategies to address potential tourist pressure.
4.4. Limitations and Future Research
This study has the following limitations. First, there are constraints related to data sources and accuracy. The temporal and spatial resolutions of remote sensing data may not be sufficient to accurately capture small-scale land-use changes. The ESV coefficients used in this study were based on comprehensive global assessments, which may not fully reflect the ecosystem characteristics of the study area. As noted in a similar study [
21], certain land types (e.g., bare land within protected areas) do not entirely lack ecological value but rather lack economic valuation studies. Therefore, when applying the benefit transfer method, we excluded these land types from the valuation. Meanwhile, since the current ESVD contains missing data on certain ecosystem services, our results may underestimate the value that those ecosystem services can provide. Secondly, there were limitations to the timescale. Since this study is an interdisciplinary project focusing on changes in LULC and ESV in Japan’s national parks after the implementation of the “To Fully Enjoy National Parks” project, only data from the past ten years were obtained, rather than a longer period. However, LULC and ESV changes may have been influenced by historical land use and management practices over a longer period. Third, this study did not integrate socioeconomic dimensions. This research mainly focuses on the ecological dimensions of LULC and ESV, potentially overlooking the interrelationship between tourism development and socioeconomic factors.
To address these limitations, we plan to improve future research projects as follows. High-resolution remote-sensing data can be used to improve data accuracy. For ESV evaluation, multi-source data can be integrated to reflect local characteristics, such as ecosystem modeling based on local environmental data, visitor surveys, and crowdsource data. Owing to the limitations of the time scale, future research could extend this period to analyze long-term trends. Additionally, scenario simulations (e.g., InVEST models) can be used to predict the potential impacts of policies on future ESV, compensating for a short time span. To address the third point, future research should expand on these dimensions by incorporating social and economic indicators to establish a more comprehensive analytical framework. For example, the coupled coordination degree model can be used to comprehensively analyze the coordinated development of ecology, socioeconomics, and tourism within national parks. Furthermore, further research could predict future land use, calculate the corresponding changes in ESV based on this framework, and develop an early warning system using other tourism-related indicators.