Boundary of ecosystem services: Guiding future development and application of the ecosystem service concepts

Ecosystem Services (ESs) are either material or non-material benefits humans receive from ecosystems. Definitions, classifications, and typologies of ESs can vary to address different research and policy purposes. However, a boundary that distinguishes ESs from other ecosystem-related benefits (e.g., industrial products that consume raw materials, fossil fuels that used to be a part of ecosystems) is needed to avoid the risk of using ESs as an all-encompassing metaphor that captures any benefit. The boundary also maintains a common ground for communication and comparison of ESs across studies. To guide future development and application of the ES concepts, we suggest five criteria. ESs are (1) primary contributions of ecosystems, (2) flows assessed during a period or per time unit (not stock existing at a time point), (3) renewable (having the potential to be reproduced with a conceivable timeframe relevant to human use), (4) affected by biotic parts of ecosystems to occur. ESs include both biotic and some abiotic flows (e.g., water provisioning) but exclude abiotic flows (e.g., wind and solar energy) whose occurrence is unaffected by ecosystem functions, processes, or characteristics; and (5) inclusive to the benefits humans actually and potentially receive from ecosystems. These criteria link ESs with conservation of life-supporting and culturally important ecosystems, recognize use, option, and non-use values of ESs, and highlight ESs' sustainability.