More than 500 species of plants have disappeared in the past 250 years potentially robbing us of sources for future drugs, new research reveals

Only 500?  I think it was a million last time I heard.  Nobody knows in reality. In 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.  But 500 extinctions is reasonable for the time period concerned.   On some estimates 99% of all species that have ever lived are now extinct.  Extinctions are a regular natural occurrence. 

And no extinction has yet been shown to be important to humans. Most recently extinct species have closely related or similar extant species.  The banded trinity, for instance, has dozens of similar species in Asia and elsewhere

The shocking number of plant species that have gone extinct in the past 250 years have been revealed by a new study.

Experts found that 500 species - more than twice the number of birds, mammals and amphibians recorded as extinct - are no longer found on Earth.

Around two species of plants go extinct every year - although the true figure is likely to be even higher as plants may be disappearing before they are even discovered, the researchers said.

Scientists at the Royal Botanic Gardens, Kew, and Stockholm University analysed all plant extinction records worldwide to arrive at the figure.

One plant - the banded trinity - has not been seen since turning up in a field in Chicago in 1916.

Others include the Chile sandalwood, a tree that grew on the Juan Fernandez Islands between Chile and Easter island and was heavily exploited for its scent.

Another is the St Helena olive, first discovered in 1805 on the island of St Helena in the South Atlantic.

One lone elderly tree survived until 1994 and two more were propagated from cuttings, but they succumbed to a termite attack and fungal infections in 2003.

The research brought together data from fieldwork, literature and herbarium specimens.

It showed how many plant species have gone extinct, what they are, where they have disappeared from and what lessons can be learned to stop future extinction.

The study found that 571 plant species have disappeared in the last two and a half centuries - four times more than the current listing of extinct plants.

The figure is also more than twice the number of birds, mammals and amphibians recorded as extinct - a combined total of 217 species.

Dr Aelys M Humphreys, assistant professor at the Department of Ecology, Environment and Plant Sciences at Stockholm University, said: ‘Most people can name a mammal or bird that has become extinct in recent centuries, but few can name an extinct plant.

‘This study is the first time we have an overview of what plants have already become extinct, where they have disappeared from, and how quickly this is happening.

‘We hear a lot about the number of species facing extinction, but these figures are for plants that we’ve already lost, so provide an unprecedented window into plant extinction in modern times.’

The scientists found that plant extinction is happening as much as 500 times faster than ‘natural’ background rates of extinction - the normal rate of loss in earth’s history before human intervention.

Islands, areas in the tropics and areas with a Mediterranean climate were found to have the highest rates of extinction.

The research suggested that the increase in plant extinction rates could be due to the same factors that are documented as threats to many surviving plants - change of land use resulting in the fragmentation and destruction of native vegetation, particularly range-restricted species.

Dr Eimear Nic Lughadha, co-author and conservation scientist at Kew said: ‘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.

‘This new understanding of plant extinction will help us predict (and try to prevent) future extinctions of plants, as well as other organisms.

‘Millions of other species depend on plants for their survival, humans included, so knowing which plants we are losing and from where will feed back into conservation programmes targeting other organisms as well.”

Commenting on the research, Dr Rob Salguero-Gómez, Department of Zoology, University of Oxford, said: ‘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. Understanding how much, where, and how plant species are being lost is of paramount importance, not only for ecologists but also for human societies.

‘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.’

The full findings of the study were published in the journal Nature, Ecology & Evolution.

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