Towards a unified ontology for monitoring ecosystem services

Ecosystem services (ES) are an important part of global and national environmental policies. In this context, there is a call for the monitoring of ES to support their management. However, the proliferation of terms used within ES science is a barrier to standardised monitoring. Monitoring ES requires knowing exactly what variables to measure and how they relate to change in the states of ES. It further requires interoperability between methodologies used by information systems to operationalise data flows. Here, we aim to systematise the language used to define ES and the terminology used in their monitoring by developing an ontology for ES monitoring. Ontologies are tools that operationalise concepts and the relationships among terms used to define them. An ontology allows people and machines to use terms consistently. Building on advances in other disciplines, the ES monitoring ontology systematises the language of ES across major conceptual frameworks advancing conceptual clarity and operationalisation of ES. We test the ES monitoring ontology with data from three ES in British Columbia, Canada, to highlight how it can enable information sharing and monitoring. We show that the ontology can organise and retrieve information and data for ES monitoring in a systematic way. Our work contributes to advancing interoperability of ES, taking a step towards systematically understanding ES change with automated tools. We invite members of the ES community to join the effort of developing this ontology for ES so that can it contribute to the challenge of systematically monitoring change in social-ecological systems.