Almost 600 plant species have been wiped from the planet in the past 250 years, more than twice the number of bird, mammal and amphibian species that have met the same fate, according to a new study.
The research -- published Monday in Nature, Ecology & Evolution journal -- found that 571 plant species have disappeared from the wild worldwide, and that plant extinction is occurring up to 500 times faster than the rate it would without human intervention.
For comparison, the researchers said animal extinction is occurring at least 1,000 times faster than the normal rate of extinction, however the report notes that researchers believe the plant extinction rate has been underestimated.
The Royal Botanic Gardens, Kew and Stockholm University researchers say it's the first time scientists have compiled a global overview of which plants have already become extinct.
"Most people can name a mammal or bird that has become extinct in recent centuries, but few can name an extinct plant," report co-author Aleys Humphreys said.
Plants on islands, in the tropics and in Mediterranean climates had the highest rates of plant extinction, as these were areas home to unique species vulnerable to human activities. The study said the increase in the plant extinction rate could be due to the loss of habitat of species located in a small geographic area.
Some examples of plants that have gone extinct in the past two centuries are the aromatic Chile sandalwood and the banded trinity, which has no leaves -- only its flowers are visible above the ground.
The issue is bigger than plants -- the authors said plant extinction had knock-on effects, including on humans.
"Plants underpin all life on earth, they provide the oxygen we breathe and the food we eat, as well as making up the backbone of the world's ecosystems -- so plant extinction is bad news for all species," co-author Eimear Nic Lughadha said in a statement. "Millions of other species depend on plants for their survival, humans included."
But there was one positive from the paper: 430 species once considered extinct had gone on to be rediscovered. However, the authors noted that 90% of rediscovered species had a "high extinction risk."
The research is the latest in a string of grim studies about the effects of humans on the world. In May, a landmark report released by a United Nations committee found that one million of the planet's eight million species are threatened with extinction.
The global rate of species extinction "is already tens to hundreds of times higher than it has been, on average, over the past 10 million years," according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), a UN committee, whose report was written by 145 experts from 50 countries.