Man hastening extinction

Conservation experts have already signalled that the world is in the grip of the “sixth great extinction” of species, driven by the destruction of natural habitats, hunting, and climate change. However until recently it has been hoped that the rate at which new species were evolving could keep pace with the loss of diversity of life.

Simon Stuart, chair of the Species Survival Commission for the International Union for the Conservation of Nature — the body which officially declares species threatened and extinct — said that point had now “almost certainly” been crossed.

“Measuring the rate at which new species evolve is difficult, but there’s no question that the current extinction rates are faster than that; I think it’s inevitable,” said Stuart.

The IUCN created shock waves with its major assessment of the world’s biodiversity in 2004, which calculated that the rate of extinction had reached 100-1,000 times that suggested by the fossil records before humans Only 869 extinctions have been formally recorded since 1500, however, because scientists have only “described” nearly 2m of an estimated 5-30m species around the world, and only assessed the conservation status of 3% of those, the global rate of extinction is extrapolated from the rate of loss among species which are known.

In this way the IUCN calculated in 2004 that the rate of loss had risen to 100-1,000 per millions species annually — a situation comparable to the five previous “mass extinctions” — the last of which was when the dinosaurs were wiped out about 65m years ago.

On the brink of being declared extinct

The IUCN lists 208 species as “possibly extinct”, more than half of which are amphibians. They are defined as species which are “on the balance of evidence likely to be extinct, but for which there is a small chance that they may still be extant”.

Kouprey (Bos sauveli)

A wild cattle with horns that live in small herds
Domain: Mostly Cambodia; also Laos, Vietnam, Thailand
Population: No first-hand sightings since 1969
Main threats: Hunting for meat and trade, livestock diseases and habitat destruction.

Spix's macaw (Cyanopsitta spixii)

A bright blue birds with long tails and grey/white heads
Domain: Brazil
Population: Extinct in wild since 2000; 78 in captivity
Main threats: Destruction of the birds’ favoured Tabebuia caraiba trees for nesting, and trapping

Webbed-footed coqui (Eleutherodactylus karlschmidti)
Golden coqui (Eleutherodactylus jasperi)

The first specimen is a large black frog living in mountain streams; the latter is a small orange frog living in forest or open rocky areas
Domain: Puerto Rico
Population: Not seen since 1976 and 1981 respectively
Main threats: Fungal disease (chytridiomycosis), climate change and invasive predators

Café marron (Ramosmania rodriguesii)

A white flowering shrub related to the coffee plant family
Domain: Island of Rodrigues, Republic of Mauritius
Population: A single wild plant is known
Main threats: Habitat loss, invasive animal species & plants