Plants and fungi sustain life on Earth. They support vital ecosystems, provide food, medicine, clothing and raw materials. But the natural world is in crisis due to climate change and biodiversity loss.
The State of the World’s Plants and Fungi (SOTWPF) 2023 report found 45 per cent of all known flowering plant species could be at risk of extinction.
The plant family Orchidaceae (orchids) is the largest in the plant kingdom and among the most threatened. It is also one of the most loved.
Orchids in danger
Dr Katharina Nargar, a CSIRO botanist at the Australian Tropical Herbarium in Cairns is a senior author of the report’s chapter on orchids. She said newly recognised plant species, including orchids, may be especially threatened.
"The report suggests as many as three in four plants that are new to science are likely to be already threatened with extinction," Katharina said.
"Unfortunately, many new plant species grow in only a single location, have a shrinking population or are losing their habitat."
Last year the Australian National Herbarium led a project to have 23 threatened orchids from Australia added to the International Union for Conservation of Nature Red List of Threatened Species. This brought the total number of Australian orchids on the Red List to 51.
Katharina said almost all of the 23 species added to the Red List are terrestrial, meaning they grow on the ground.
"This is because Australia has a rich diversity of terrestrial orchids. In contrast, the majority of orchids worldwide are epiphytic, meaning they grow on trees," she said.
"Adding orchids to the Red List helps raise awareness about Australian orchids and creates opportunities for people working to conserve orchids. Australia has about 1600 native orchid species. Around 90 per cent are endemic to Australia, meaning they occur nowhere else in the world.”
The origins of orchids
New research presented in SOTWPF report used DNA sequencing to challenge previously held beliefs on the evolution of orchids.
"New genetic data suggests the orchid family did not originate in Australia as previously thought," Katharina said.
"Instead, the first orchids lived in the northern hemisphere during the time of the dinosaurs, around 83 million years ago. From there, orchids spread across the world. Australia’s largest orchid lineage, which accounts for over 60 per cent of Australia’s orchid species diversity, originated in Australia and dates back more than 40 million years.
“In contrast, most orchid species worldwide originated fairly recently in Earth’s history, within the last five million years.”
The Australian Tropical Herbarium and the Australian National Herbarium contributed approximately 20 percent of the original DNA sequence data for the study, covering approximately 80 percent of Australian orchid genera. This was through participation in the Bioplatforms Australia led Genomics for Australian Plants initiative, which sequenced more than 90 per cent of Australian flowering plant genera.
More surprising origins
Cycads are another group whose origins have been challenged by SOTWPF. A study by scientists in France and Austria combined fossil and genetic data to reveal these ancient plants originated some 300-360 million years ago. They occurred at much higher latitudes than today.
Extinction has been a common theme throughout the history of cycads, from the age of the dinosaurs to the modern day. Today only 370 species of cycad remain and 68 per cent are threatened with extinction. Conservation efforts are particularly hampered by illegal trade and poaching.
Fungi waiting to be discovered
Very little is known about the diversity of fungi when compared to plants. Only 155,000 species of fungi have been formally named. Now, thanks to SOTWPF, scientists estimate there are about 2.5 million species of fungi globally.
This means more than 90 per cent of fungi are waiting to be discovered. Among them could be new sources of food, medicine, chemicals and enzymes with useful properties such as plastic degradation.
The State of the World’s Plants and Fungi 2023 report was published by Royal Botanic Gardens Kew. The science behind the report was published in a special collection from the journals New Phytologist and Plants, People, Planet entitled ‘Global Plant Diversity and Distribution’ and in a review of global fungal diversity and conservation published by the journal Annual Review of Environment and Resources.
The Australian National Herbarium is a joint venture between us and Parks Australia. The Australian Tropical Herbarium is a joint venture between us, James Cook University and the Queensland and Australian governments.