This paper mentions the importance of including non-use values in ecosystem services valuation.

Evidence of a Shared Value for Nature

Ecosystem service analysis aims to expand the accounting of human values for nature, yet frequently ignores or obfuscates a category of human values with potentially large magnitude, namely nonuse or passive use values. These values represent the satisfaction derived from the protection or restoration of species, habitats and wilderness areas, even if people never use them in any tangible way. The shunting of nonuse values to the background of ecosystem service analysis appears, in part, to be an attempt to avoid the perceived elitism of environmental values. To examine whether such values are the purview of the elite, we explore three types of evidence of who holds nonuse values. We find that when people are asked to 1) commit money via stated preference instruments, 2) respond to tweets, or 3) express opinions via surveys they demonstrate a significant willingness to protect and restore natural resources, regardless of their own use of those resources. Such values are represented in all socio-demographic groups that encompass race, ethnicity, immigration status, income, political affiliation, geographic location, age or gender, although the magnitude can vary among groups. The implications are that omitting nonuse values in ecosystem service analysis will tend to underestimate values, particularly for remote sites with limited use, and fail to represent important tradeoffs.