Progress developing the concept of other effective area-based conservation measures.

In 2010, the introduction of Other Effective area-based Conservation Measures (OECMs) into international policy caused a paradigm shift in area-based conservation, including areas outside of formal protected areas and places where biodiversity conservation may not be a management objective. Despite the importance of this shift for global conservation efforts, conservation science and policy have been slow to engage with the concept of OECMs. As the world moves towards protecting 30% of the Earth by 2030, it is imperative to develop evidence-based guidance for how to identify effective conservation measures. Especially, tools to help evaluate and monitor the biodiversity outcomes associated with potential OECMs. To understand the current progress in developing the concept of OECMs, I evaluated the peer-reviewed literature to consolidate and synthesize the current knowledge-base. I found very few studies that discuss OECMs, and those that do rarely move beyond superficial mention of OECMs as part of area-based conservation. Around half of relevant studies listed potential risks and/or benefits of OECMs but none provided evidence these issues have materialized. A small number of studies attempted to identify potential OECMs, although case studies were rare. The seven studies that evaluated existing OECMs were highly critical of how they have been implemented to date. Studies that evaluated conservation outcomes were extremely rare and suggest effectiveness must be judged on a case-by-case basis. The current literature not only leaves many gaps in the science required to operationalize the concept of OECMs, but often raises additional questions that need to be addressed. If these gaps are not filled by robust science, the promised benefits for biodiversity from OECMs may never be realized. This article is protected by copyright. All rights reserved.