Presentation short abstract

The IUCN Red List is considered one of the most comprehensive and objective sources of global biodiversity information. This presentation explores the uncertainties that underpin Red List assessments, how they vary across taxa and regions, and what this means for conservation research and practice.

Presentation long abstract

With over 172,000 species assessed, the IUCN Red List is widely considered to be the most comprehensive, robust and objective source of information on globally threatened animal, fungus and plant species. It underpins several influential global conservation initiatives, is an important input into a number of key biodiversity metrics and is one of the most common data layers used in global priority mapping exercises. However, despite its status and the apparent precision implied by the elegantly coloured maps and figures, the Red List is still affected by considerable uncertainties (Lovari 2020). For example, our knowledge of global biodiversity status and trends is still beset by significant shortfalls (Hortal et al. 2015) and although the quantitative criteria emphasise objectivity, the subjective judgement of individual experts continues to play a key role in shaping parameter estimates and assessment outcomes (Regan et al. 2005). Drawing on an exploration of existing trends and patterns in the Red List data and interviews with assessors, this presentation explores what types of uncertainty impact Red List assessments, how they vary across groups and regions and the extent to which these uncertainties are made visible to potential users of the Red List. I ask what the Red List knows, how it knows it, and what is at stake when the uncertainties in our knowledge are obscured.