The International Union for Conservation of Nature (IUCN) released its updated Red List of Threatened Species at the UN's COP16 biodiversity summit in Cali, Colombia, on Monday.

Numerous birds, reptiles, amphibians and especially trees feature in the dire paper, which found that of 166,061 species of plants and animals, more than a quarter — 46,337 — are threatened by extinction.

Alarmingly, trees, which were included in the report for the first time, accounted for more than a quarter of all species on the list — more than double the number of all threatened animals combined.

The report found that 38% of all tree species are in danger of extinction, under threat from deforestation for urbanization and agriculture, disease, invasive species and pests as well as climate change and rising sea levels.

IUCN Director General Grethel Aguilar told those gathered, "Trees are essential to support life on Earth through their vital role in ecosystems, and millions of people depend upon them for their lives and livelihoods."

Hedgehog populations being destroyed 

One beloved mammal, however, featured prominently in the report — the Western European hedgehog (Erinaceus europaeus) — the status of which was moved from "least concern" to "near threatened." With numbers plummeting dramatically, scientists fear the spiny creatures will soon have to be reclassified as "vulnerable" and eventually "endangered."

Over the past decade, hedgehog numbers have declined in more than half the countries in which they live, including Austria, Belgium, Denmark, Germany, Norway, Sweden and the UK. In the Netherlands they are already listed as endangered.

The Red List report estimates that national populations have decreased between 16-33% — with some regions such as Bavaria, Germany, and Flanders, Belgium, seeing populations plummet by 50%.

In the UK, a 2022 study found that rural hedgehog populations had declined by a staggering 75% since 2000, though urban populations had shown minor signs of recovery.

Hedgehogs, which live an average of two to three years but can live as long as 10, can breed at 12 months, bearing three to five hoglets with each pregnancy, not nearly enough to sustain their population.   

'Humans are the worst enemies of hedgehogs' 

The main threat to hedgehogs said researchers, is loss of habitat due to human activity — with automobiles being their single biggest killer.

Another threat is loss of food supply due to the extensive use of pesticides by farmers, gardeners and homeowners. These kill off the insects, worms, snails and slugs that hedgehogs feed on, or poison hedgehogs directly.

Robotic lawnmowers have also emerged as a major threat, as their blades can fatally injure the creatures.

Experts have implored homeowners to let hedges grow, mow less, use fewer pesticides and to do things like leaving small holes in perimeter fences so that hedgehogs can move freely off the street and from yard to yard, as well as putting out water and creating spaces where they can shelter.

In the wild, hedgehogs, which are night active, defend themselves from predators like badgers, foxes or owls by freezing in place when approached. In flight mode, they scurry off as quickly as possible into underbrush. As a last resort, they roll themselves into a spiky ball with their 8,000 or so quills pointing in every direction. 

"In front of a car," says Danish researcher Sophie Rasmussen, "it isn't a really good strategy."

Rasmussen is clear, saying, "Humans are the worst enemies of hedgehogs," adding that although the world will keep turning when the last hedgehog is gone, "for a species so popular and so loved, can we really accept the fact that we are causing their extinction?" 

Echoing the plea scientists are making about the need to halt and reverse "catastrophic" declines in animal and plant life, Rasmussen says, speaking of the tiny mammals, "And if we let it get so bad with a species we actually really care about, what about all the species we don't care about?"

js/nm (AFP, dpa)