Economic valuation of the influence of invasive alien species on the economy of the Seychelles islands

Biodiversity underpins most economic activities in Seychelles, and loss of biodiversity as a result of invasive alien species (IAS) could result in major negative economic impacts for the country. This paper assesses the value of impacts of IAS on biodiversity, natural resources and the national economy, using the principles of total economic value (TEV). The contingent valuation method was used to obtain a willingness to pay (WTP) estimate for a policy to protect important biodiversity from IAS. Tourists indicated a mean WTP of US$52–US$58 on top of their usual expenditures to fund conservation policy. At present approximately US$0.25 million per year is spent on IAS control while the economic damage associated with 4 key IAS is approximately US$21 million per year. Comparing the benefits from eradication with the costs involved gives a benefit-cost ratio greater than unity, indicating that the policy of eradicating IAS is economically justified. However, there is a long way to go before the resources devoted to the problem will be in proportion to the risks.