Do you root for Sharks? Are you a Bears fan? Or are the Bengals more your team? Today,
on DNews we’re rooting for apex predators!
Hi Everyone, Crystal here for DNews. From saber tooth tigers to imaginary monsters under
our beds, powerful apex predators have caught human attention since prehistoric times. We
imitate them, we worship them, we display their teeth, heads, and claws as trophies
and ultimately, we’re completely terrified of them.
Apex predators are so called because of their position at the very top of the food chain.
You can think of the space they occupy in an ecosystem as the peak segment of the ecological
pyramid. Nobody preys on them! and they, eat the lower species making up the wider pyramid
below.
But today, I’m not here to talk about why we should be afraid of them. I’m here to
tell you why we should all appreciate the apex predator for the helpful, stabilizing
influences they really are.
Apex predators play a critical role in what scientists call the “Trophic Cascade”.
The trophic level of an organism defines its position in the food chain. Apex predators
sit at the highest trophic level, and a cascade is described by something like: Tiger Sharks,
eat sea turtles, that eat sea grass.
Perhaps the most publicized example of a trophic cascade comes from Yellowstone National Park
and it all starts with the wolf. The culling of wolves from the park to near extinction
in the 1930s and 40s lead to severe consequences including a reduction in biodiversity and
a concerning disappearance of aspen, cottonwood, and willow trees due to overgrazing by elk,
wolves natural prey. Several articles published by Beschta and Ripple from Oregon State University
documented the impact of wolf reintroduction on diversity and landscape, demonstrating
that wolves relieve the pressure placed on flora by herbivores, leading to more robust
areas of woody growth which consequently strengthen and improve habitats for species like bison.
But there are multiple cascades affected by size of elk population and for some, we may
not have acted quickly enough.
A decade long study performed by scientists at Colorado State University and published
in the Proceedings of the Royal Society B, showed that after almost a hundred years without
them, simply reintroducing wolves wasn't enough for the Park’s waning willow tree which
are a tasty treat for elk. The willow tree supplies food and habitat for beavers whose
activities temper the seasonal ebbs and flows of river runoff, recharge the water table;
and provide an ideal environment for fish.
Now, even with elk populations back under predatory control, ecologists are discovering
that they must gently finesse the balance between beaver and willow to halt riverbank
erosion and channel widening which of course have negative “downstream” consequences
… see what I did there? ;)
This all just goes to show that when we attempt to pick one thing out of an ecosystem, like
the scary and predatory wolf, we find it “hitched to everything else” and the system falls
apart.
Okay, at this point, you all might be thinking “I get it. Apex predators keep everything
in check, but what keeps apex predators in check so that they don't over feed and collapse
entire ecosystems on their own?” The answer to that, is two fold. Of course apex predators
are sensitive to the availability of prey, if they over hunt their territory, lack of
available food will have a shrinking effect on their population. But apex predators are
typically large animals with longer gestation periods, so reproducing takes time and a lot
of energy. A recent study published in the journal OIKOS even suggested that community
behavior might come into play. Observing that some apex predators control the size of their
own populations though infanticide and preferential breeding.
Either way, the energy demands to hunt, defend their territory from intruders, breed, and
raise their young are very high for apex predators. This means that much of their time is dedicated
to defense and reproduction and they only hunt when they have to. Just another reason
to respect apex predators.
For some apex predators of the sea, tune into Shark Week which kicks off Sunday, June 26th
8/7c
Or watch this video by Tara on what we can do to keep sharks from going extinct
What do you think? Do predators make the world a better place? Or should we let our herbivore
friends graze in peace? Subscribe to DNews and let us know in the comments down below.
Thanks for watching!