Toward a standard lexicon for ecosystem services.

The complex, widely dispersed, and cumulative environmental challenges currently facing society require holistic, transdisciplinary approaches to resolve. The concept of ecosystem services (ES) has become more widely accepted as a framework that fosters a broader systems perspective of sustainability and can make science more responsive to the needs of decision makers and the public. Successful transdisciplinary approaches require a common language and understanding of key concepts. Our primary objective is to encourage the ES research and policy communities to standardize terminology and definitions, to facilitate mutual understanding by multidisciplinary researchers and policy makers. As an important step toward standardization, we present a lexicon developed to inform ES research conducted by the US Environmental Protection Agency and its partners. We describe a straightforward conceptualization of the relationships among environmental decisions, their effects on ecological systems and the services they provide, and human well-being. This provides a framework for common understanding and use of ES terminology. We encourage challenges to these definitions and attempts to advance standardization of a lexicon in ways that might be more meaningful to our ultimate objective: informing environmental decisions in ways that promote the sustainability of the environment upon which we all depend.