Developing a rapid method for undertaking the World Ocean Assessment in data-poor regions – A case study using the South China Sea Large Marine Ecosystem

• We develop a practical method for assessing marine ecosystems in data-poor regions.
• We use a hierarchical and adaptable assessment framework using expert elicitation.
• Biodiversity, ecosystem health and environmental pressure components are assessed.
• The method facilitates future WOA assessments of large data-poor marine ecosystems.

The United Nations Environment Program, World Ocean Assessment, requires rapid assessment of the state of marine ecosystems at regional scales, yet a practical method for achieving this in data-poor regions has not been developed. We present a method that is capable of synthesising information across a broad range of ecosystem components in a timely manner, while also overcoming the paucity of empirical data available at large spatial scales. We develop a hierarchical and adaptable assessment framework that encompasses ‘Biodiversity’, ‘Ecosystem health’ and ‘Environmental pressure’ components, which are further divided into parameters (representing the structure and/or function of each component) and indicators (which indicate the spatial distribution of the assessed parameter). We argue that this framework is best utilised within an expert elicitation process. To determine the validity of this framework in undertaking a WOA, this approach was applied to the South China Sea Large Marine Ecosystem during a 3-day pilot workshop held in Bangkok, Thailand, 2012. Forty-five experts from 11 countries in the region participated in assessing the biodiversity, ecosystem health and environmental pressures structuring 104 pre-identified ecosystem variables. The majority of areas within the SCS were graded as ‘Poor’ in terms of their biodiversity, with biodiversity in decline within 64% of these variables. In contrast, most areas were graded as ‘Good’ for ecosystem health, with 51% of variables considered stable in terms of ecosystem health. However, most areas were graded as ‘Poor’ for ecosystem pressures, with pressures either stable or increasing. Ecosystem variables in ‘Poor’ or ‘Very Poor’ condition in Most (80%) of areas were identified as conservation priorities. These variables were primarily associated with groups of taxa, including elasmobranch fauna, inner-shelf demersal fishes, squid and large invertebrate species inhabiting reefs (e.g., giant clam). A range of iconic species (e.g., dugong), key habitats (e.g., coral reefs), and key ecosystem processes (e.g., benthic productivity) were also graded as ‘Poor’ in Most (80%) of areas. Confidence in condition and trend scores was assessed to be medium or high for 86% of variables assessed. The rapid method developed here assessed and conveyed to policy-makers a broad-scale overview of the condition, trends and issues in the SCS. The method provides a way forward for future World Ocean Assessments of large data-poor marine ecosystems.