The United Nations' Millennium Assessment estimates that the current rate of species extinction is 1,000 times greater than it would be without human-induced habitat change, introduction of invasive species, and overexploitation. Last month, the World Conservation Union's (IUCN's) 2007 Red List, an annual report on the conservation status of the world's species, provided a more thorough accounting of this biodiversity loss. The IUCN reports that one in four mammals, one in eight birds, and one in three amphibians are in jeopardy (see table below).

More than 7,000 species experts from around the world collaborate to evaluate the status of more than 41,000 species. The Red List is unique in its global scope and the breadth of life that it examines; it includes invertebrates, plants, fungi, and algae. However, while many species groups, such as birds and mammals, are evaluated comprehensively, only a small percentage of invertebrates, plants, and fish are classified. In total, fewer than three percent of the world's 1.6 million described species have been systematically evaluated. As a result, the number of species that are actually under threat could be much higher than the results given in the table below.

Threatened Species in 2007

Source: Table 1, IUCN Red List.

This year's report includes some success stories. The Mauritian parakeet (pictured at the top of this post) was upgraded from Critically Endangered to Endangered after years of intensive recovery management. However, many other species, including the Indian crocodile, the Western gorilla, Speke's gazelle and the Egyptian vulture were assigned a more threatened status in this assessment (see http://www.iucn.org/themes/ssc/redlist2007/going_updown_2007.htm for more information).

For the first time this year, the Red List included species of corals. Several species endemic to the Galapagos Islands, facing the twin threats of El Nino and climate change, have been classified as endangered. Marine species are typically underrepresented in these assessments, and the IUCN is working to classify the conservation status of 15,000 additional marine species by 2010.

Additional Information
For specifics about the great apes, corals, dolphins, and others on this year’s list, see the interactive map of species case studies that is a companion to the Red List.

Scientific American published several scientists' responses to this question nearly a decade ago:
What is the point in preserving endangered species that have no practical use to humans, apart from their aesthetic appeal or their intellectual interest to biologists?

The Convention on Biodiversity, signed by 168 countries, links traditional conservation efforts to the economic goal of using biological resources sustainably.

EarthTrends Resources
Data Table: Species Diversity and Conservation Status
Freshwater Biodiversity in Crisis
For Wild Tigers, An Uncertain Future
Rare Chinese Dolphin Declared Extinct