A new research article in the latest issue of the Science for Environment Policy’s newsletter presents a study which uses decision science to evaluate nine biodiversity indices.

The researchers performed a structured evaluation based on decisсon science on indices commonly used to report on biodiversity targets across marine, freshwater and terrestrial habitats— the Living Planet Index, Red List Index, Marine Trophic Index, Ocean Health Index, River Health Indices, Climate Impact Indicator, Index of Biotic Integrity, Biodiversity Intactness Index and Forest Area as a proportion of total land area. The aim of the study was to qualitatively evaluate the indices against five criteria: objectives, design, behaviour, uncertainty, and constraints (for example, costs and data availability).  

The ultimate goal of this study is to close a gap in the assessment of essential biodiversity-index features (such as the total number of species in a community or 'species richness'). The authors look at different factors, for example if it is apparent which component of  biodiversity is the indicator meant to assess, how easy it is to comprehend changes in the indicator value, and if the mathematical structure is justified. 

The authors observed that four of the indices did not adequately describe the relationship between the means goal and the measure utilised to aggregate data based on their analysis. Only four of the nine indices addressed approaches for assessing uncertainty: the Living Planet index, Red List Index, Biodiversity Intactness Index and Climate Impact Indicator. They also revealed that only the River Health Indices took into account expenditures in its entirety.

These findings imply that the indices' shortcomings may render them inefficient in certain decision-making situations tied to biodiversity targets and sustainability goals. The findings indicate that biodiversity indices could be improved by setting clear objectives and an explicit model understanding of how the indicator connects to key biodiversity processes. Updating indices with the aim to overcome the existing gaps will improve their accuracy and value in addressing environmental change, and make them more well suited to benefit global policy choices.

More info about the study here.

Photo: Butterfly on a flower. Credit: Anne Nygård from unsplash.com.