The stakes of the question are enormous. Aso’s volcanic landscape, particularly its grasslands, acts as a vast natural sponge. Forests, grasslands, and agricultural land regulate infiltration, evapotranspiration, runoff, and water storage, recharging the groundwater that feeds six major rivers, including the Chikugo and Shirakawa Rivers. Roughly 2.3 million people across Kyushu depend on this water for domestic use, and the Chikugo River system alone supplies about 30 percent of the municipal water for the Fukuoka metropolitan area, home to approximately 2.5 million people. Yet the ecosystem functions behind this supply are quietly eroding. Japan’s aging and depopulating rural communities can no longer maintain the grasslands through traditional burning and grazing, while urbanization has paved over paddy fields that once recharged aquifers. Without conservation measures, the researchers estimate, groundwater recharge would decline by roughly 4 million cubic meters of water every year.

Because these benefits are not traded in markets, their economic value can go unrecognized, leaving water-source areas underfunded. The contingent valuation method, or CVM, is the classic tool for making such invisible value visible. Respondents are presented with a hypothetical conservation program and asked how much they would pay for it, allowing economists to quantify use and non-use values alike. Previous CVM work in the region showed real financial support: a study by Yamane and colleagues estimated that Kumamoto City residents would pay a median of 1,045 yen per household per month for groundwater conservation policies. But a crucial empirical question remained open. Previous research had demonstrated that symbolic species can inflate stated conservation values, yet almost nothing was known about whether the same mechanism applies to symbolic places. Does naming the landscape that provides an ecosystem service change its perceived value, even when the service itself is described identically?

To find out, the team ran a randomized controlled experiment embedded in a nationwide internet survey conducted through the contractor Nikkei Research between December 7 and December 21, 2020. About 80 percent of the 8,407 respondents were drawn from Kyushu, the primary beneficiary region, with the remainder included to capture values among geographically distant populations whose valuation may reflect non-use values. After screening out respondents who withheld income information or answered that they did not know, the final analytical sample comprised 6,448 valid responses, roughly half university graduates, with a mean age of about 48 years.

The experimental design was elegantly minimal. All respondents received the same information about the water-related ecosystem services of forests, grasslands, and paddy fields, their contribution to groundwater recharge, the expected 4 million cubic meter annual decline, a map of the river systems, and a conservation program funded by a household tax added to water bills. Willingness to pay was elicited with a payment card spanning 0 to 20,000 yen or more per year. The only difference was one sentence. In the treatment group, respondents read that the mountains in the Aso region supply approximately 62.9 billion cubic meters of water annually to Kyushu prefectures. In the control group, the identical figure was attributed generically to mountains, without reference to Aso. Because the quantity of water, the expected reduction, the conservation activities, the payment vehicle, and the payment duration were held constant, any difference in stated value could be attributed to the place name itself.

The results upended the researchers’ primary hypothesis. In the pooled sample, the conservative Turnbull lower-bound mean was 1,825.69 yen per household per year when Aso was mentioned, rising to 2,009.83 yen when it was not. The Kriström mean, which takes the midpoint of each payment range, showed the same direction: 1,997.89 yen with the name versus 2,186.35 yen without. Within Kyushu, the pattern was statistically significant. A Mann-Whitney U test rejected the null hypothesis of equal willingness-to-pay distributions between the informed and uninformed groups, with a small but significant negative effect size. By contrast, outside Kyushu the trend reversed: the nonparametric estimates rose from 1,835.17 yen to 1,916.88 yen when Aso was named, although this difference was not statistically significant. The authors suggest that for people beyond Kyushu, Aso functions as a symbolic representation of the region’s mountains, whereas for Kyushu residents it is simply one mountain among many.

To probe the determinants of stated value, the team complemented the nonparametric estimates with an interval regression model that respects the interval-censored nature of payment-card responses, treating each respondent’s latent maximum willingness to pay as lying between the lower and upper bounds of the chosen range. The coefficient on the Aso information variable was negative in every full-sample specification, statistically significant in most, and implied, after transformation, an 11.3 to 25.5 percent decrease in willingness to pay when the name was provided. Crucially, none of the interaction terms between the Aso treatment and Kyushu residence, urban residence, or frequency of visits to water sources was significant, offering no evidence that the effect differed systematically across these groups. Respondents in Kyushu, frequent visitors to rivers, forests, and water sources, women, older respondents, university graduates, higher-income earners, and those with greater environmental knowledge all reported higher willingness to pay, with income and knowledge showing particularly strong associations.

Why would a famous name reduce stated support? The authors propose a perceived scope effect. Although the amount of water protected was identical across treatments, respondents may have interpreted the Aso-specific scenario as covering a geographically narrower area than the generic reference to mountains, changing not only the salience of the name but also the perceived spatial scope of the conservation target. Alternative explanations, including beliefs that a famous destination already receives sufficient public funding or doubts about the need for additional support, cannot be excluded. The absence of a positive Aso premium also contrasts sharply with previous findings on charismatic species, suggesting that recognizable place names may operate differently from recognizable species names in the psychology of stated preference. The authors caution that binary geographic indicators cannot capture continuous distance, watershed location, or actual dependence on Aso-derived water, so more localized spatial effects remain possible.

The study carries a practical message for conservation finance. Regardless of information provision, the demographic and behavioral profile of high stated value, women with university degrees, higher incomes, and deeper knowledge of how ecosystems retain water and recharge groundwater, points to a potential target for funding conservation efforts. Fostering a deeper public understanding of the ecosystem services provided by forests, grasslands, and paddy fields may be a more effective strategy than simply naming the place. The authors also acknowledge limitations: the payment-card format may be susceptible to range effects, internet surveys carry risks of respondent inattention, and hypothetical bias is inherent to contingent valuation. Future work should vary the place name independently of the conservation area’s stated boundaries and compare stated values with revealed-preference evidence. For now, the lesson is counterintuitive and viral in its implications: when it comes to paying for water, fame may not be the currency that counts.

Subject of Research: Environmental Economics

Article Title: Place-specific information and its heterogeneous effects on willingness to pay for water resources: a case of Aso, Japan

Article References: Wakamatsu, M., Kumagai, J., & Managi, S. (2026). Place-specific information and its heterogeneous effects on willingness to pay for water resources: a case of Aso, Japan. Environmental Challenges, 25, Article 101682. https://doi.org/10.1016/j.envc.2026.101682

Image Credits: AI Generated

DOI: 10.1016/j.envc.2026.101682

Keywords: contingent valuation, water resources, ecosystem services, Aso, Japan, willingness to pay, conservation finance, Kyushu, Place-specific, information, heterogeneous, effects