A choice experiment was applied to measure the existence value of an endemic moss. We assessed value separation, embedding or warm glow and ‘ethical’ motivations. We exemplify our application by valuing an inconspicuous moss endemic to Chile's sub-Antarctic region. The choice experiment was administered to a sample of local residents of Navarino Island (southern Chile). The design isolates the existence value by requiring respondents to make simultaneous tradeoffs between moss existence value, five other biodiversity-related values and income changes. Insensitivity to scope was addressed by using degrees of extinction risks. We predominantly use a willingness-to-accept design of the payment vehicle to avoid protest responses. A meaningful marginal value for the existence of an endemic species for Navarino island residents was documented. The design, based on varying degrees of extinction risk, avoided a strong effect of warm glow. No protest responses motivated by ethical concerns were encountered.