Floral biodiversity risk of extinction: orchids at high risk

In alarming news, it has been estimated that up to 45% of recorded flowering plant species are threatened by extinction.

The new study State of the World’s Plants and Fungi (SOTWPF) 2023 released by the Royal Botanic Gardens, Kew and supported by Australia’s national science agency CSIRO, found “plant species are dying out at least 500 times faster than before humans existed… [It is] predicted this figure could rise to 10,000”.

Out of the estimated 100,000 vascular plant species still undiscovered, 75,000 are considered endangered. It says 77% of undescribed plant species are likely threatened with extinction, and that the more recent a species has been described, the more likely it is to be threatened.

Vascular plants are classified as trees, shrubs, ferns and flowering plants.

“Fourteen of the 32 global plant diversity darkspots are in tropical Asia,” says the report.

Dr Katharina Nargar, senior author of the chapter on orchids, says “plants and fungi sustain life on Earth and provide valuable ecosystem services, food, medicine, clothing, and raw materials. But the natural world is threatened by the dual crises of climate change and biodiversity loss.”

One endangered family is the Orchidaceae (orchid).

The orchid’s origin was initially recognised to be from Australia, but DNA sequencing has expanded botanical knowledge.

“New data suggests the orchid family did not originate in Australia as we thought. Instead, it originated in the northern hemisphere around 83 million years ago before it spread across the world.”

The threat of extinction to the Orchidaceae species has increased in a year from 23 types of orchids (2022) to 51 (2023).

“Almost all of the 23 orchid species are terrestrial, meaning they grow on the ground, showcasing the rich diversity of terrestrial orchids found in Australia. In contrast, most orchids worldwide are epiphytic, meaning they grow on trees.”

“The findings indicated that epiphytes were the most threatened plant form, while those with an annual life cycle were the least threatened,” says the report.

“We have observed newly described species only known from a single location, or are really uncommon with very narrow ranges,” says Dr Eimear Nic Lughadha, an editor for Kew report.

The study has created 6 types of predictors, ranking them by influence of extinction risk. The highest predictor risk is how widespread the plant is.

When newly described species are limited to a single location and possess a narrow range, it creates a greater risk of extinction for the plant species.

“Understanding extinction is critical to conserving biodiversity, but unless we increase the current rate of scientific naming, we are in danger of losing species before they have been described… If we are to safeguard biodiversity in order to keep Earth’s crucial systems functioning, everyone must play their part.”