Population collapse
The following list -- hardly comprehensive, I'm quite sure -- lists some of the things that are believed to be on the edge of catastrophic population collapse:
- Bananas (CNN, Dan Koeppel book, NPR, Snopes (which disagrees))
- Bats (Boston Globe, NPR)
- Bees (Fox News, New York Times, Wikipedia)
- Frogs & other amphibians (New Scientist, New Scientist (2), NPR, Scotsman, Washington Post)
- Polar bears (AFP, CBC, New Scientist, San Francisco Chronicle)
- Russians (Christian Science Monitor, BBC, VOA, Wall Street Journal, Wikipedia)
- Salmon (BBC, Fox News, San Francisco Chronicle, Scientific American, USA Today)
Okay, so maybe "Russians" is an odd fit for this list, but it still seems part of a pattern here, somehow.
Common explanations seem to include fungus infections (weird to me, but frequently cited as a possible cause), global warming, habitat destruction, human hunting, etc. But some of these -- particularly bananas & bees -- are being actively cultivated by humans, and still seem to be at risk in spite of our efforts to nurture them.
The twenty-first century scares me when I think about it too much.