Animal Species Under Threat

Around the world, numerous species of animals and plants are going extinct, leading many scientists to speculate we're now in an historic era of mass extinctions. Many of the die-offs can be blamed on human activity and climate change, but some stand out both for their dramatic nature and the uncertainty of their cause.

Among the top species suffering from massive die-offs or disappearances, either worldwide or locally:

1. Bees. Researchers are still trying to find the answer to why large populations of bees simply vanish from their hives. Known as colony collapse disorder (CCD), the mysterious malady has affected bee populations across numerous U.S. states, as well as in Europe. Just this week, the ice-cream maker Häagen-Dazs announced it was granting $250,000 to researchers to study CCD. The reason? The company says almost 40 percent of its ice-cream flavors rely on crops that are pollinated by bees.

2. Frogs. A chytrid fungus is causing frogs and other amphibians around the world to die from an infection known as chytridiomycosis. The U.S. Centers for Disease Control (http://www.cdc.gov/ncidod/EID/vol10no12/03-0804.htm) calls the infection one of the biggest threats to amphibian populations across the globe. Scientists believe the disease threatens nearly one-third of Earth's amphibians.

3. Bats. A malady known as white-nose syndrome is killing tens of thousands of bats across the Northeastern U.S. The condition is marked by an area of white fungus around the infected bat's nose. Researchers aren't sure how the disease is spread, but it's already been found in almost every major bat hibernation cave in the state of New York.

4. Birds. Twenty of the most common North American bird species have seen major population declines of 50 percent or more over the past 40 years, according to the National Audubon Society. Humans are to blame in most cases, the society says, either directly through development and agriculture, or indirectly via climate change. "These are not rare or exotic birds we're talking about -- these are the birds that visit our feeders and congregate at nearby lakes and seashores and yet they are disappearing day by day," said Carol Browner, Audubon's chairperson. "Their decline tells us we have serious work to do, from protecting local habitats to addressing the huge threats from global warming."

5. Fireflies. Many areas in the U.S. no longer see as many flashing "lightning bugs" during summer nights as they once did. It's probably not because you caught a few dozen every July and kept them in a Mason jar, though: the more likely culprits are pesticide use and over-development.

6. Horseshoe crabs. Known as "living fossils," horseshoe crabs have been around for nearly 400 million years. They're found up and down the Atlantic Coast as well as in Florida, but some people believe their numbers are declining. The Ecological Research & Development Group was founded in 1995 to make sure the four remaining species of horseshoe crab continue to survive.