Orson Scott Card reviews Where the Wild Things Were, which makes the case that top predators can play important roles in maintaining a healthy, well-balanced ecological system:
For instance, the coastal waters of several north Pacific shores had little sea life — mostly a few huge sea urchins that consumed anything else that might sprout.Then sea otters were reintroduced to these shores. Sea otters love to eat sea urchins. And with the sea urchin population falling, plant life began to thrive again. When the seaweeds and other plants returned, fish also came back to the newly-lush jungle.
Sea otters, in other words, made a rich ecology possible because they, as top predators, kept down the voracious sea urchins.
Or take Yellowstone. For generations there has been almost no new growth among the key species of trees. Why? Because the elks eat the new saplings right down to the ground. With their favorite foods gone, there were too many elk — and they were starving.
Hunters were fine with that — the more elk there are, the more licenses to hunt them that get issued.
But then wolves were reintroduced to Yellowstone, and the surprising result was that wolves killed far fewer elk than human hunters — but changed elk behavior in such a way that new trees were able to grow.
Why? Because wolves hunt by chasing their prey until their hearts or lungs give out and they stand there, exhausted, to be hauled down and torn apart.
Elks quickly learned to avoid streambeds, because it was precisely as they slowed to climb the far bank that the wolves invariably caught up with them. Elks on riverbanks were in greater danger than anywhere else; they learned not to linger there.
And since riverbanks are where most trees grow in the American west, the elks’ avoidance of those areas allowed huge numbers of new shoots to grow until they had a chance of thriving as actual trees. And the small animals that thrive in that environment now had new habitat. Again, a whole ecology was restored.
So wolves, in effect, promote forest growth!
Meanwhile, human hunters never had any such effect. What can the elks learn from the annual elk hunt? To avoid public lands in October and private lands in November?
(I’ve noted before how returning wolves to Yellowstone changed the ecosystem.)