ANALYSIS Valuing local endangered species: The role of intra-species substitutes ☆ Maria L. Loureiro a,b, ⁎ , Elena Ojea b a Department of Economic Analysis, Universidade de Santiago, Spain b IDEGA, Universidade de Santiago de Compostela, Campus Sur, Avda das Ciencias, S/N. 15782, Santiago de Compostela, Spain ARTICLE INFO ABSTRACT Article history: Received 5 November 2007 Received in revised form 10 February 2008 Accepted 6 April 2008 Available online 14 May 2008 Valuation of endangered species is important in many circumstances, and particularly when assessing the impact of large accidental oil spills. Previous studies have tested the effects of including in the contingent valuation survey reminders about the existence of diverse substitutes (in terms of other natural resources also in danger of extinction in the same area, other programs to be valued, or alternative uses of money). We include a reminder about the existence of the same biological species not being under danger of extinction elsewhere. We believe this reminder allows individuals to make an easy assessment of the biological scarcity of the species they are supposed to value. Thus, the key difference with previous studies is that valuation of endangered species is combined with an assessment of preferences towards conservation of local and native species. Our WTP results are not sensitive to the information provided about other foreign substitutes. Implications of this finding are discussed. © 2008 Elsevier B.V. All rights reserved. Keywords: Contingent valuation Endangered species Substitutes 1. Introduction It is expected that the existence of a substitute of the good or asset being valued may decrease the mean willingness to pay (WTP) estimate when valuing such a resource. This expecta- tion was put forward when the NOAA panel (Arrow et al., 1993) recommended the inclusion of references to possible substitutes of the good being valued. In line with the NOAA panel guidelines, there is an important debate about the role that substitute goods may potentially play on the valuation process of the good or resource of interest. Diverse studies have tested the effects of considering substitute goods or substitute prices in the valuation scenario (Boyle et al., 1990; Loomis et al., 1994; Neill, 1995; Whitehead and Blomquist, 1995; Kotchen and Reiling, 1999) with mixed results. Boyle et al. (1990) value single day hunting trips when participants are reminded about variations of prices of substitutes, pro- viding unclear results with respect to the changes of sub- stitute prices on WTP estimates for hunting different species. Loomis et al. (1994) and Kotchen and Reiling (1999) reminded survey participants of the existence of other species threa- tened by extinction, or other places in which the recovery program of interest would have no effect. A number of these studies rejected the hypothesis of sensitivity of the WTP estimates when substitutes are presented (see for example Loomis et al., 1994; Kotchen and Reiling, 1999), while others have shown that information about reminders can signifi- cantly affect WTP estimates (Whitehead and Blomquist, 1995). Cummings et al. (1994) and Hailu et al. (2000) examine the effect of substitute programs on the one being valued, ECOLOGICAL ECONOMICS 68 (2008) 362 – 369 ☆ The authors whish to thank, without implicating, John Loomis for comments on earlier versions of this manuscript, participants of the BIOECON-2006 conference, and two anonymous referees for their comments and suggestions. ⁎ Corresponding author. Tel.: +34 981563100 14337; fax: +34 981528031. E-mail address: maria.loureiro@usc.es (M.L. Loureiro). 0921-8009/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.ecolecon.2008.04.002 available at www.sciencedirect.com www.elsevier.com/locate/ecolecon