Researchers from the Royal Botanic Gardens Kew, the Zoological Society of London, and Boise State University published findings in Science showing that more than one fifth of flowering plant evolutionary history faces extinction risk. The team conducted the first comprehensive global assessment of threat to angiosperms, the dominant plant group on Earth.
The study maps extinction risk across the angiosperm family tree, revealing that certain plant lineages carry disproportionate evolutionary significance. When a species goes extinct, it erases not just its genetics but an entire branch of evolutionary history. Some plant families possess millions of years of unique evolutionary development that cannot be recovered if those species vanish.
The researchers linked extinction vulnerability to specific traits and environmental pressures. Plants in tropical regions, those with small populations, and species with limited geographic ranges face the highest risk. Island ecosystems show particular vulnerability since endemic species depend on isolated habitats offering no refuge.
The 20 percent figure represents something deeper than species counts. It reflects the loss of evolutionary distinctiveness. A plant species that represents an ancient lineage with few living relatives carries more evolutionary weight than a recent species with many close relatives. Losing such species erases millions of years of evolutionary history that took eons to develop.
This assessment carries implications for conservation priorities. Resources are limited, so protecting species with high evolutionary distinctiveness offers greater value than protecting closely related species. The findings suggest current conservation efforts may not adequately prioritize these irreplaceable lineages.
The study also highlights knowledge gaps. Scientists still lack complete extinction risk assessments for many plant species, particularly in biodiversity hotspots like tropical rainforests. Full accounting of threat levels remains incomplete.
Human-driven habitat destruction, climate change, and invasive species drive angiosperm extinctions. Flowering plants form the foundation of terrestrial ecosystems, supporting herbivores, pollinators, and entire food webs