Biophysical Measures to Support Analysis and Communication of Existence Values
A recent focus of ecosystem services research has been on the definition of biophysical outcomes and measures that are most closely linked to social welfare. Various terms are used for these commodities, including “ecological endpoints,” “final ecosystem goods and services,” and “linking indicators.” This paper reviews economic and ecological evidence to answer the questions: (1) What are ideal characteristics of linking indicators for existence values?; (2) What types of ecosystem outcomes or services are most likely to be associated with significant existence values?; and (3) What measures tracked by natural scientists are most likely to serve as valid linking indicators for these outcomes and services? We begin with a brief introduction to the concept of existence value. This is followed by a discussion of relationships between existence values and linking indicators, focusing on the foundational question: The existence of what? We then explore the interdisciplinary literature related to different categories of ecosystem outcomes and services often associated with existence values. Using examples from the literature, we attempt to draw general conclusions regarding the types of indicators most likely to facilitate quantification of biophysical outcomes related to these values.