  It is crucial that societies are informed on the risks of impoverished
ecosystem health for their well-being. For this purpose, Ecological Integrity
(EI) is a useful concept that seeks to capture the complex nature of ecosystems
and their interaction with social welfare. But the challenge remains to measure
EI and translate scientific terminology into operational language to inform
society. We propose an approach that simplifies marine ecosystem complexity by
applying scientific knowledge to identify which components reflect the state or
state change of ecosystems. It follows a bottom-up structure that identifies,
based on expert knowledge, biological components related with past and present
changing conditions. It is structured in 5 stages that interact in an adaptive
way: stage 1, in situ observations suggest changes could be happening; stage 2
explores available data that represent EI; stage 3, experts' workshops target
the identification of the minimum set of variables needed to define EI, or the
risk of losing EI; an optative stage 4, where deviance from EI, or risk of
deviance, is statistically assessed; stage 5, findings are communicated to
society. We demonstrate the framework effectiveness in three case studies,
including a data poor situation, an area where lack of reference sites hampers
the identification of historical changes, and an area where diffuse sources of
stress make it difficult to identify simple relationships with of ecological
responses. The future challenge is to operationalize the approach and trigger
desirable society actions to strengthen a social-nature link.
