From ecosystem integrity to ecosystem condition: a continuity of concepts supporting different aspects of ecosystem sustainability

The current emphasis on sustainable development and ecosystem services promotes the need to better understand long-term ecosystem integrity and ecosystem functioning. This secures long-term provision of ecosystem services and ecosystem conservation. Ecosystem integrity or related notions are referred to in several national and international biodiversity and ecosystem policies that couples ecosystem integrity with human well-being. However, it is still poorly defined. The scientific literature has mobilized an array of terms and notions attempting to conceptualize and describe degrees of ecosystem intactness or alteration. Based on a review of papers proposing ecosystem integrity indicators, we identify five forms of ecosystem integrity which we define their specificities: ecosystem integrity of wilderness, ecosystem functional and structural integrity, ecosystem stability and reliance, ecosystem condition and ecosystem quality and value. These five forms gather into two main strands by the link to conservation ecology or to ecosystem services. Through this clarification, this work provides a platform for more streamlined and comprehensible development of policies and scientific agendas for sustainable development/conservation purposes.