Global failure to track international biodiversity targets on islands

Abstract

Islands harbour exceptional biodiversity but face severe threats, making their conservation crucial to achieving the Kunming-Montreal Global Biodiversity Framework. To evaluate progress toward its 23 targets across islands worldwide, we screened 504 biodiversity and socioeconomic indicators, and retained 47. We modelled historical time series from 1950, then projected to 2030. Progress was uneven: nine targets improved across all available indicators, while nine displayed conflicting trends. Critically, 15 of 23 targets (65%) lacked a suitable headline indicator, and five had none. Furthermore, 29 of 47 indicators (62%) were reported nationally, potentially obscuring island conditions. Most targets also lacked quantitative objectives, limiting evaluation of whether change rates suffice for 2030. Overall, progress toward halting island biodiversity loss remains insufficient and unlikely to meet the Framework targets.