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Follow the Bears

Double the number of conservationists at work in the field right now, quadruple it even, and the task before them would still be overwhelming. There's simply too much out there, too many plants and animals, too many acres. No wonder, then, that these people are always on the lookout for more efficient methods. One example is the use of so-called indicator species to monitor habitats.

Indicator species are plants and animals that can serve as representatives for entire areas. If a particular salamander, for instance, one identified as an indicator species, suffers ill effects as the result of development near its habitat, then other species in the area have probably suffered as well. In fact, the habitat as a whole might be threatened. What the salamander offers conservationists, in other words, is advanced warning of a potentially disastrous situation.

Aside from salamanders, scientists often use frogs as indicator species when tracking the health of wetlands. If the local frog population drops, there's reason for concern. In Hawaii, certain butterfly fish have been used as indicator species for monitoring coral reefs. Meanwhile, in the Great Plains, government biologists believe that Coyotes show both numerical and behavioral responses to environmental change.

The most recent announcement about indicator species comes from a zoologist at North Carolina State University who's studying whether Black Bears can offer clues about the health of forests in the Appalachian Mountains. The hope is that by measuring the habitat quality for a single large and easy-to-track species it's possible to assess the habitat quality for numerous other species, too.

And how does one measure habitat quality for Black Bears? For starters, the area must have ample food for the bears, items like berries, acorns, and insects. In addition, there must be sufficient cover available for bears to hide from humans.

Once a correlation between habitat quality and bear population is established, the next step will be demonstrating that other species respond similarly to these shifts. Bird censuses will play a key role here. But if there's agreement later that Black Bears can function as indicator species for these Appalachian forests, such counts will no longer be necessary. Instead, managing the forests to protect Black Bear habitats will preserve habitats for other species as well.

 

 

 

 

 

2007 eNature.com