Laura Erickson's For the Birds

In today’s Birds in the News, from The Scientist:

More than 15,000 species around the world are at risk of extinction, according to a report released November 17 by the International Union for Conservation of Nature and Natural Resources. The organization, whose annual list of endangered species is commonly known as the “Red List,” found that one in eight birds, almost half of turtles and tortoises, one in four mammals studied, and one in three amphibians is threatened.

“We are in the midst of the sixth great extinction wave on the planet Earth, caused by the intervention of humans,” David Brackett, Species Survival Commission Chair of the study, told The Scientist. “Species should come and go on an evolutionary time scale, not on our time scale.” Bracket said that “objective information is showing that declines are not limited to vulnerable species, but are happening across the entire taxonomic spectrum.”

The report is the work of 8,000 volunteer conservationists in 179 countries and is considered the most comprehensive study of threatened species by international conservationists. It found that 15,589 species—3,300 since the last such report in 2000, most likely because amphibians are now included—are at risk of extinction.

One major notable shift is that continental extinctions have become as common as extinctions on islands, which are normally thought of as more ecologically fragile. The report concluded that the current extinction rate is 100 to 1,000 times the “natural” evolutionary rate.

In a press release, Craig Hilton-Taylor, co-editor of the report, wrote, “Although 15,589 species are known to be threatened with extinction, this greatly underestimates the true number, as only a fraction of known species have been assessed. There is still much to be discovered about key species-rich habitats, such as tropical forests, marine and freshwater systems, or particular groups, such as invertebrates, plants, and fungi, which make up the majority of biodiversity.”

In both plants and animals, according to the report, species were most likely to be at risk if they had slow growth rates, small populations, and low reproductive rates—species such as sharks and the great apes. But regardless of the characteristics of the species, humans are either directly or indirectly the main reason for most species’ declines, according to a press release by the International Union. Threatened species are exposed to significant pressures that include over-exploitation, invasive species, pollution, and disease.

The next step, according to Sam Gon, director of science at The Nature Conservancy’s Hawaii division, is to “look at what is necessary to preserve habitats to benefit the maximum [number] of endemic species.” Hawaii has been particularly vulnerable to species loss: it contains a mere 0.2 percent of U.S. land but holds a quarter of the endangered species in the United States. The Red List acts as “an official list that often brings status and funding to taxa that may not get attention at all,” Gon told The Scientist. “You don’t have to know everything to take action,” he said.