Extinction is a part of life, and animals and plants disappear all the time. When a species goes extinct, its role in the ecosystem is usually filled by new species, or other existing ones. Earth’s ‘normal’ extinction rate is often thought to be somewhere between 0.1 and 1 species per 10,000 species per 100 years. This is known as the background rate of extinction.
A mass extinction event is when species vanish much faster than they are replaced. This is usually defined as about 75% of the world’s species being lost in a ‘short’ amount of geological time – less than 2.8 million years. We have had five of those events.
Unlike previous extinction events caused by natural phenomena, the “sixth mass extinction” of plant and animal species is the first mass extinction event driven by a single species-humans, primarily (though not entirely limited to) from the unsustainable use of land, water and energy, and climate change. Currently, 40% of all land has been converted for food production.
As temperatures continue to increase across the globe, plants that once thrived in their native habitats are either being forced to adapt to new conditions or accelerate the rate of extinction.
The rate by which plants are going extinct is at an all-time high across the globe. Since 1900, nearly 3 species of seed-bearing plants have disappeared per year ― 500 times faster than they would naturally. In so far as plants form the infrastructure of ecosystems and are interdependent with other organisms, when a plant species goes extinct it can harm every other species in the ecosystem.
Dramatic changes to the structure of a previously stable ecosystem can result. For example, the average time between fires in the Yellowstone National Park ecosystem is projected to decrease from 100 to 300 years to less than 30 years, potentially causing coniferous (pine, spruce, etc.) forests to be replaced by woodlands and grasslands.
Submerged plant communities, like mangroves and seagrasses may be most affected by warming temperatures. Mangroves are vital habitats for young marine life, and they protect coasts from storms. A dangerous feedback loop begins as the loss of mangroves then leads to further loss of biodiversity and more extreme storms.
Almost half of all known flowering plants are at risk of extinction. Tragically, thousands of plant and fungi species may go extinct before they are even named. Biodiversity loss is threatening vital ecosystem services - some that we don’t even know about yet.
Warming temperatures also allow more invasive species to thrive.
Over 40% of pharmaceutical formulations derive from nature, including drugs for cancer, Parkinson’s and Alzheimer’s disease. There could be medicinal properties and potential drugs we don’t even know about yet that we are at risk of losing forever.
Now, scientists are working to understand what can be done to lessen the impacts of climate change on endangered plant species and save them from extinction.
CREDIT: CARBON BRIEF
Six main predictors of plant extinction risk and their significance. CREDIT: Kew Gardens, State of the World’s Plants and Fungi (2023), adapted from Bachman et al (2023).
