made by keeping in mind that respective subdivided values contain the following two valuation axes:

(i) Natural science-based valuation: Investigate and show the state of nature and to what problems nature is exposed.

(ii) Social science-based valuation: Show the significance to humans and what values are offered to humans.

As methods to evaluate the value of natural environment by substituting it with things that already have market values, there are the output evaluation method, prevention expenditure method, damage cost method and alternative method, etc. However, the evaluation cannot be made unless there are substitutable market goods. The value that cannot be converted into monetary value has to be evaluated qualitatively. For example, as the landscape and the function of preserving ecosystems do not have substitutable market goods, they cannot be evaluated using the above-mentioned methods.

According to “The Economics of Ecosystems and Biodiversity (TEEB), D1 (For Policy Makers)”, in a local development project, as commercial profits are often given priority and ecosystem services are underestimated, the act of development tends to be judged commercially feasible. When government subsidies are excluded and post-development restoration costs are taken into account, however, ecosystem services turn out to be larger than expected benefits from not undertaking the development project exceed benefits from development. For example, in a project to develop a shrimp farm by cutting down mangroves, the project most likely is assessed only from the aspect of economic gains to be obtained by a developer. When the economic effects of the shrimp farm and benefits from mangroves are compared, the former is judged considerably larger (the left-hand graphs in Figure 3-1-13). However, the shrimp farm development project is funded by government subsidies, and when this support factor is excluded, the economic effects of the development is reduced to about one-eighth (the middle graphs in Figure 3-1-13). Further, in addition to the profits to be gained by the developer, when the benefits of the development and mangrove conservation are compared, including public costs necessary to restore the functions of mangrove forests on the site of the shrimp farm five years later and public benefits from preserving mangrove forests, the benefits of conservation prove to be larger than the benefits of development (the right-hand graphs of Figure 3-1-13).

Meanwhile, efforts to economically evaluate ecosystem

Figure3-1-13 Relationship between Benefits from Shrimp Farm Development and Public Benefits of Mangrove Forest

services are under way in Japan as well. For example, around Kabukurinuma (wetlands designated under the Ramsar Convention, in Osaka, Miyagi Prefecture), known as one of the largest destinations of anatine birds in Japan, the economic value of ecosystem services (maintaining the number of anatine birds coming to the wetlands at the current 70,000) protected by environmentally-sound farming around the wetlands has been analyzed. The analysis was made using the conjoint method, under which a survey is carried out by presenting multiple environment conservation measures to potential respondents and asking them to rank their desirability to evaluate the economic value. A nationwide questionnaire survey for a six-day period via the Internet drew a total of 3,257 responses (the response rate at 21.6%). The survey results put the willingness to pay at an average ¥1,007 per household per year, which is estimated to total ¥53.2 billion when extended to the total number of households of 52.88 million in Japan (as of March 2009) (based on "Policy Research on Environmental Economics," Associate Professor Managi and Professor Kuriyama).

As seen above, by translating the economic value of ecosystem services into monetary value, it becomes possible to compare the economic value of development and the economic value maintained through conservation as well as the costs involved in both.