15,568 species now face extinction

The number of threatened species on the planet is increasing at unprecedented rates across almost all major animal groups, according to the most comprehensive evaluation of the world’s biodiversity ever undertaken.

A total of 15,568 species now face extinction, according to the 2004 Red List of Threatened Species published on Wednesday by the World Conservation Union (IUCN). This represents a rise of 3300 species compared to the 2003 list. One in three amphibians and almost half of all freshwater turtles are now threatened, as well as one in eight birds and a quarter of known mammals.

For the first time, the Red List includes an index that shows the overall change in threatened status and the projected risk of extinction for each particular species group. The conclusion is that there is an even greater sense of urgency, says Simon Stuart at Conservation International, Washington DC, US.


The distinctive rostrum of the Largetooth sawfish often becomes entangled in West Pacific fishing nets

Callum Rankine, international species officer for the World Wildlife Fund, agrees: “Year-on-year we know that the situation is getting worse, but this time it just seems to be getting worse much faster."

New to science

There is still much to be understood about key species-rich habitats, such as tropical forests, marine and freshwater systems, says Craig Hilton-Taylor, one of the Red List’s authors. This is despite these appearing to be some of the ecologies most at risk.

For example, in Madagascar more than half the freshwater fish now face extinction. One of these, a type of killifish which is so new to science it has not yet been formally named, used to live in what was the Sakaramyi River.

But this has now been diverted for domestic water supplies leaving the last remaining specimens of this fish existing in “a handful of puddles”, sustained only by poor plumbing. “If all the people in Madagascar fixed their taps, these fish would die out,” Hilton-Taylor says.

Human geography

In addition to the list itself, the IUCN published results of a four-year analysis entitled the Global Species Assessment (GSA) which highlights problems not just in terms of biodiversity but also in terms of human geography and socioeconomics.

For example, although some countries like Australia, Brazil, Indonesia and Mexico have a disproportionately high number of species at risk, the number of threatened species is likely to increase more rapidly in regions where human population growth rates are high, such as in Cameroon or India. “This is the first time we have been able to overlay species distribution maps with population growth data,” says Stuart, one of the authors of the GSA.

Habitat loss is by far the greatest threat to biodiversity but, in regions where human population growth is particularly high, “the traditional protected area approach might not work”, says Hilton-Taylor.

The challenge lies in finding ways to enable people living in poverty to develop a sustainable relationship with their local resources. “But it’s extremely difficult to get these people to live sustainably, because often they are just concerned with trying to live,” says Rankine.

The new data also offers the chance to identify countries for pre-emptive conservation initiatives. In countries such as Bolivia, Papua New Guinea and Namibia, there is currently a low human population density but a high rate of population growth, which could threaten wildlife in the future.

Duncan Graham-Rowe