摘要:In the economics of biodiversity, the relevant policy question is the level of certainty of species survival, rather than the simplistic binary problem of species preservation or extinction. In this study models of cui-ui survival probability and economic cost of water transfer are developed to estimate the cost of an endangered species preservation: the Northwestern Nevada cui-ui fish. There is a cost of over 160 million dollars to increase the likelihood of cui-ui survival by 2 percent, from 53 to 55. The cost increases to over 2 billion dollars to increase the likelihood of cui-ui survival by 22 percent, from 63 to 85. These findings highlight the economic tradeoffs associated with modifying the survival likelihood of an endangered species. These results also confirm quantitatively the biological fact that the survival uncertainty must explicitly enter any discussion of species preservation.