Twice as many plant species have gone extinct in the last 250 years than amphibians, mammals, and birds combined, according to a new analysis published in the journal Nature Ecology and Evolution.

Conclusions from the first comprehensive report of global plant extinctions suggest that almost 600 plants have gone extinct since the middle of the 18th-century. It’s a pace that has never been seen before – about two plant species each year – and is largely due to human-driven environmental and climatic changes.

“Plants underpin and provide key resources to entire ecosystems worldwide. However, much of the effort to quantify the loss of species diversity worldwide has focused on charismatic species such as mammals and birds,” said British Ecological Society committee member Rob Salguero-Gómez, who was not involved in the study, in a statement. “Understanding how much, where, and how plant species are being lost is of paramount importance, not only for ecologists but also for human societies.”

To come to their conclusions, scientists analyzed detailed records and reports of over 1,200 known extinct species based on physical sightings, specimens, and publications. They found that the rate at which plants are going extinct is 500 times baseline levels of 1 to 5 species every year. Between 1753 and 2018, 571 plant species have been driven to extinction – four times higher than previous estimates by the Red List of Threatened Species, which suggested that less than 150 plant species had gone extinct. Extinctions are the highest in biodiversity hotspots like islands, the tropics, and species with narrow ranges like certain shrubs and trees. Overall, the researchers found no clear genetic or evolutionary pattern as to what makes one species more likely to go extinct when compared to another, which makes predicting survivors of ongoing climate change more of a challenge, potentially hindering future conservation efforts.

“We depend on plants directly for food, shade and construction materials, and indirectly for ‘ecosystem services’ such as carbon fixation, oxygen creation, and even improvement in human mental health through enjoying green spaces,” said Salguero-Gómez.

The findings confirm an earlier report published by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) highlighting the dangerous “unprecedented” decline of “accelerating” species extinction rates. Today, over 1 million species are threatened with extinction, and as many as 135 animal, plant, and insect species are going extinct every day. 

The paper also notes that researchers had rediscovered some plant species that were previously recorded as extinct but have since been spotted growing in the wild again. Still, they face a 90 percent chance of becoming extinct.