NEWS - The current rate of human-caused extinction is up to 700 times higher than it was in the past. Extinctions are no different for plants, animals and fungi, although the extinctions of botanicals and invertebrates have been far worse than those of vertebrates.
The mass extinctions increased from 1890 to 1940, but a decline in extinctions was only recorded after the 1980s, likely due to taxonomic bottlenecks and the pre-1800 extinction rates being affected by a lack of data.
The number of species varies from 2-8 million to 1 trillion, and estimates suggest that most species, especially microbes and fungi that may be key to healthy ecosystems, are still undiscovered. The biodiversity crisis is therefore extremely difficult to measure.
“If we don’t know what we have, it’s impossible to measure how much we’re losing. This taxonomic gap urgently needs to be addressed,” say Maarten Christenhusz and Rafaël Govaerts of the Royal Botanic Gardens, Kew.
Yet taxonomy is in decline. Misunderstandings about taxonomy and its function as a science have led to a dismissive attitude in the scientific community and funding bodies. Many areas of the world remain biologically understudied and therefore require more experts to better understand global biodiversity.
The highest extinctions occur in areas rich in biodiversity due to high human influence. Anthropogenic plant extinction is a global phenomenon with hotspots being the Hawaiian Islands, southern Africa, Australia, the Indian Subcontinent, Southeast Asia and Brazil. This is mainly due to land clearing for agriculture and urbanization, mining, hunting etc.
Data from 2020 states that the 20 countries with the highest number of botanical extinctions are South Africa with 160 species, Hawaii - USA (99), USA - excl. Hawaii (76), Australia (69), Sri Lanka (61), Brazil (36), China (31), Mauritius - excl. Rodrigues (28), Philippines (24), Cuba (22), India (20), Mexico (17), Chile (16), Madagascar (14), Italy (13), Indonesia (13), Colombia (12), Rodrigues (12) and St Helena - UK (11).
Unusual weather patterns associated with rapid climate change are leading to more plant extinctions. Reintroduction, even if a species remains in cultivation, is not always possible due to habitat loss. Reintroduction is expensive and usually relies on short-term funding, after which the effort may be wasted.
Original research
Maarten J M Christenhusz, Rafaël Govaerts. Plant extinction in the Anthropocene. Botanical Journal of the Linnean Society, 2024, boae045, DOI:10.1093/botlinnean/boae045