Apex Predators and Ecosystems

Moonrise. Yellowstone NP, Wyoming, 2013

It seems to me that the environmental folks have not done an adequate job explaining to the general public just how an ecosystem works and the importance of the apex predators in those ecosystems.

One quick example that springs to my mind: The controversy over the Spotted Owl versus the possible loss of jobs in the Pacific Northwest logging industry back in the 1990s. For the masses, it seemed a simple question of deciding between whether we wanted to save some stupid little bird, or have economic growth. Here’s the problem, and here is what the environmentalists needed to explain…

An ecosystem is like a house of cards. You can start pulling out random cards and, initially, your house of cards will remain standing. But, at some point, you will pull out a card–say, some seemingly insignificant creature like a Mexican long-nosed bat (pollinators), or the Stephens’ kangaroo rat, or the Giant leaf frog–and the ecosystem will collapse. If not collapse, it will become seriously debilitated. And we’ll never know exactly which might be the “last card.”

All of this is important because we are part of the Earth’s ecosystem. The more we degrade these ecosystems, the more we put in danger our own survival as a species.

Healthy ecosystems give us…

–Healthy soil and water

–More diversified agricultural food sources–less prone to collapse in the case of a single-crop failure

–More diversified stock animal populations

–Flood protection

–Seacoast storm protection

–Healthy and varied fish populations, thus more abundant marine food resources

–Cleaner air and a better capacity for the Earth to generate O2 and absorb CO2

–More capacity to clean and filter polluted water, air and soil

–More possible sources for medicines and drugs

–A healthy “savings account” for future, unforeseen, needs

–Recreation, outdoor activities, general enjoyment of the miracle that is the Earth and her systems

Now, how do apex predators fit in? They are sort of like “health indicators” of the condition of an ecosystem. If you see that the apex predators are missing (wolf, Polar bear, mountain lion, sharks), or endangered, there is a good chance that the ecosystem is under severe stress or is in danger.

In the U.S., we spent much of the early centuries killing off these apex and other lesser predators (foxes, coyotes, grizzlies, etc.). Indeed, even as late as the 1970s of my youth (and probably even today), I know of hunters who would go “varmint hunting” to kill whatever predator they could find–mostly coyotes as they seemed to be the most common “varmints”.

This has thrown our ecosystems so out of whack that hunting is actually a necessity now to keep things in balance. Without the predators, the elk and deer overpopulate. This means these animals have a greater than normal impact on the riparian areas, the grasslands, the brushy areas. This, in turn, affects the creeks and rivers, the fishing, and the bird, rodent and reptile populations. Overpopulation of deer and elk also lead to more diseases, weakened herds, possible large die-offs during a harsh winter, and so on. Everything in an ecosystem is inter-related.

In the oceans, the sharks act as the health indicators–and they are being hard pressed by fisherman and the demand for cheery things like shark fin soup and shark fin home remedies. We don’t necessarily see it as easily, but through acidification and overfishing, our oceans may be one of the hardest hit of Earth’s ecosystems. (Take a look at the various “dead zones” around the world, including the some thousands of square miles surrounding the Mississippi delta.)

In the forest and mountains, the wolf can be a good index of overall environmental health. As a culminating example of how ecosystem-apex predator thing all works, check out this short video (about 4 1/2 minutes) about the introduction of the wolf into the Yellowstone area. Within a few years of the wolf’s arrival, the elk and deer herds increased their health (and more normal behavior), the beavers came back, the number of hawks increased, even the fly fishing got better…all through something called the “trophic cascade” effect…