Ecosystem extent is a necessary but not sufficient indicator of the state of global forest biodiversity

Abstract The Kunming‐Montreal Global Biodiversity Framework lays out an ambitious set of goals and targets aimed at halting and reversing biodiversity loss. The extent of natural ecosystems has been selected as one of a small set of headline indicators against which countries will report progress under this framework. We evaluate the effectiveness with which this indicator is expected to capture the overall scope of the ecosystem‐focused component of Goal A, and interlinkages with the species‐focused component of this same goal, using extensive global data on the integrity, connectivity, and plant species composition of forests. Results generated for all forest‐supporting countries demonstrate that consideration of these additional factors can profoundly alter understanding of the state of forest biodiversity relative to that based on extent alone. Employment of ecosystem extent as a headline indicator must therefore be augmented by appropriate use of component and complementary indicators addressing other key dimensions of ecosystem change.