Non-market valuation approaches for estimating the social value of biodiversity and individual species need
to enhance their policy relevance. The concept of service-providing unit (SPU) may help achieve this
objective by promoting the systematic quantification of the key components of nature that provide services
for human wellbeing. The present paper is the first application of the SPU concept in stated preference
surveys. The object of valuation is the highly endangered Mediterranean monk seal (Monachus monachus).
A split-sample is used testing the hypotheses that the SPU framework would: 1) minimize the part of non-use
values that is due to a ‘warm glow’ effect and therefore 2) encourage respondents in reallocating part of their
total economic value towards use values. Our results indicate that the difference between the means of existence
values in the two sub-samples is statistically insignificant: in both cases respondents attribute a significant
percentage of their total economic value to existence value. On the other hand though, the non-use value
component ofWTP decreases in the sub-sample with SPU in relation to the sub-sample without it. We conclude
that existence values in our sample are based on solid preferences related to the species since they persisted in
both sub-samples.