[Editor's note: Get the entire Decade's Top 10 Earth Stories list here]
If the 1990s saw the popularization of the poster animal — the most majestic or cuddly of at-risk species — then the past decade saw conservation interest democratized. Yes, animals like tigers and pandas still maintain their totem status on holiday cards; polar bears, classified by the U.S. Department of the Interior as a "threatened species" in 2008, even became the plush face of global warming and an impetus to change.
But endangerment consciousness broadened to include the less photo-ready: The latest IUCN Red List reported that 17,291 species were threatened. That's 21 percent of known mammals, 30 percent of amphibians, 70 percent of plants and 35 percent of invertebrates. The decade also saw a better understanding of endangerment's fluidity as animals like wolves, grizzlies and eagles rebounded after aggressive protection.
Other species thrived without help, often to the detriment of natives. Invasive species, intruders or opportunistic expansionists long recognized on a local level, are now considered wreakers of global havoc. Species like the zebra mussel, the Colorado potato beetle and kudzu have become almost anti-totems, warnings that biodiversity is of real economic value. And with 2010 ushering in the International Year of Biodiversity, that's a timely message for the decade's end.
What does global global warming have to do with the decline in the polar bear population?
Why are wolves making a comeback in the United States?
Is wolf hunting legal?
Why is the birth rate so low for giant pandas?
How did the bald eagle get delisted as an endangered species?
Image credit: You might recognize a scene like the one above from this year's holiday cards. (Tom Brakefield/Digital Vision/Getty Images)