Many people can name a bird or a mammal that has become extinct in recent centuries, but few can name a plant that has suffered the same fate. Researchers at the Royal Botanic Gardens, Kew and Stockholm University recently found that at least 571 plant species have gone extinct since 1750 — and that's twice the number of all bird, mammal and amphibian extinctions combined, according to a Kew media release.
The figure was calculated when study co-author Kew scientist Rafael Govaerts reviewed all publications on plant extinctions over more than 30 years and found the number to be four times more than the current listing of extinct plants.
According to Govaerts, creating a list of extinct plants was an exhaustive task. He wrote about the experience on the Kew website, "I gathered data on all plant extinctions by screening relevant scientific publications since 1988, visits to herbaria, and field trips to search for plants declared extinct, which I made during my holidays."
Researchers say the data suggests plant extinction is happening about 500 times faster than what would be expected without human intervention. Their findings were published in the journal Nature Ecology and Evolution.
They found the highest rates of extinction to be on islands, in the tropics and in areas with a Mediterranean climate. The main cause of extinction was destruction and loss of habitat, often due to human activity.
Species that disappeared and some that reappeared
Species driven to extinction include Chile sandalwood, which was exploited for essential oil and hasn't been seen since the early 1900s, and the St. Helena olive tree (shown at the top of the page) which was wiped out after a devastating termite attack and fungus infection in 2003.
The researchers, however, did find that 430 species once considered extinct have gone on to be rediscovered. These include the Chilean crocus, a colorful, popular bulb rediscovered in 2001 after years of never being seen.
"While some species have been rediscovered and safeguarded, currently the list contains 571 documented plant extinctions, most of which are now unlikely to be rediscovered. Many of the plants that have gone extinct could have offered solutions for food security or medicines but unfortunately, we will never know of their value," Govaerts wrote.
"The true figure of plant extinction is of course much higher as the list I compiled are only those species scientists have documented and searched for. Many more plants are only known from their original collection or historic specimens. All need to be searched for again to document surviving populations and protect them from the continued destruction of wild places and devastation to ecosystems."