For ecosystem services analysis, a key to collaboration between natural and social scientists is the identification and measurement of linking indicators: biophysical indicators that facilitate social evaluation, including monetary valuation of ecological changes. As ecosystem service analysts and practitioners better recognize the various ways in which people benefit from ecosystems, natural scientists will be called on to develop, use, and report on metrics and indicators that link to those diverse benefits. This paper develops principles to guide the identification of linking indicators; compares their features with those of more commonly collected ecological measures; and reviews empirical evidence pertinent to their identification, definition, and performance, primarily from the point of view of conducting monetary valuation of ecological outcomes.
