The term apex predator, besides being a good band name, is an important designation in any given ecosystem. The name refers to those critters at the very top of the food chain, who tend to have big claws, big teeth and big appetites. They also have a big impact on their environment.
As Crystal Dilworth explores in this DNews dispatch, apex predators are nature's tough guys -- heavyweight carnivores like tigers, bears and wolves. These animals typically live in habitats where they eat all kinds of other animals, but no one tries to eat them.
It seems like a sweet deal, but apex predators actually bear a lot of responsibility in their respective ecosystems. Biologists have gradually come to appreciate the stabilizing effect that apex predators provide. Biodiversity goes quickly downhill when these creatures are, for whatever reason, removed from the top of a local food chain. Their absence can trigger the devastating phenomenon known as a trophic cascade. (Also a good band name.)
One of the most famous documented examples of a trophic cascade occurred in Yellowstone National Park in the 1930s and 1940s. After wolf populations were culled to near extinction, botanists were mystified when the park's aspen, cottonwood and willow trees also started disappearing.
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Well, not literally disappearing -- that would be mysterious -- but the trees' seedlings were in serious decline. Scientists eventually connected the dots: With the wolves out of the picture, the park's elk were overgrazing on various flora. The decline of woody habitats was, in turn, impacting hundreds of other species up and down the food chain.
Researchers followed the subsequent changes for decades and uncovered the remarkable impact of the trophic cascade. For instance, the missing willow trees decreased food and habitat options for beavers. Fewer beavers resulted in fewer beaver dams, which impacted river runoff, water tables and fish populations.
Check out the video for more details on apex predators and strategies that wildlife officials have deployed to adjust biodiversity factors in our national parks.
-- Glenn McDonald
Wiley Online Library: What Is An Apex Predator?
Oregon State University: Large Predators and Trophic Cascades in Terrestrial Ecosystems of the Western United States