The Predator Prey Relationship

Leaping for mice by Ellison photography

So in order to understand Coyote’s important role in the ecosystem a little more, let’s touch upon the function of predator prey relationships in sustaining biodiversity on our planet.

To start, what is “biodiversity” anyway? Actually, the word itself tells us ~ “bio” and “diverse” ~ life that is diverse.  And why is it so important, and what does it have to do with our lives?  The complex diversity of life on our planet is what keeps our planet healthy and dynamic. And this affects us in our everyday lives, from the diversity and balance of organisms in your gut, to the food you eat, and on and on. Our organic farmers here in Maine know so well that growing monoculture crops year after year in the same place is an invitation to disaster for them. That lack of diversity will quickly invite insects who will devour all their hard labor, and there will be no back up of other plants that can withstand or hold off the insect invasion.

Maine Forest by Jim St Pierre

So here is a powerful historical example of the disaster that can happen due to lack of diversity ~ the Potato Famine in Ireland. The Irish grew ONE, and only ONE strain of potato, and when that strain of potato was infected by a fungus in 1845, one million people died of starvation. Had they planted with some diversity, this tragedy would not have happened.

So now, let’s take this whole concept into the larger ecosystem of our planet and its diversity. When you walk through a natural ecosystem, what do you see?  And what is it that you do not see?  Often there is little comprehension of the immense changes to a landscape due to ecosystems dominated by herbivores (ex: moose and deer) and mesopredators (ex: raccoons, skunks, fox).  And why?  … because it was long ago that a shift in large predator presence occurred.  So we do not have a relevant baseline to observe or measure biodiversity.

But we do know that biodiversity is a matter of dynamic processes and interactions, as well as species diversity.  So when species are lost, the species interactions are lost as well.  The functional loss of apex predators cascades down to the loss of species at lower trophic levels, and thus the loss of large carnivores can have far reaching effects on the functioning of an ecosystem. It is like taking the entire violin section out of an orchestra! … the music falls apart.

When herbivore populations are unchecked by predation, they have the ability to denude landscapes, and carry the threat of succumbing to epidemic diseases.  That denuding of the landscape can be the beginning of the end of biodiversity on that landscape. The predation pressure placed on herbivores by apex carnivores influences their density and behavior, thus strongly effecting their habitat selection and feeding decisions. The result of this causes profound effects on the structure of ecological communities.

Photo: Tim Springer

In fact, behavioral changes in herbivores due to predation pressure can be as significant as direct predation.  That is, the very presence of a top carnivore on the landscape affects the behavior of the herbivore.  They don’t stay in one place too long, they make different choices of where they will feed, and how many of them will congregate together.

An example of this ~ one of our Maine farmers related to me that deer and coyotes live on his farm.  Before the coyotes included his farm in their territory, the deer were insatiable, eating his crops without reserve. When the coyotes settled in, the deer knew of their presence, and their behavior changed.  No more hanging out in his garden all night.  A few bites and they moved on, knowing that staying in one place made them more vulnerable.

It has been found that even though one or two predators have the greatest impact on prey populations, that predator guilds of up to five carnivores may be necessary to promote ecosystem function and biodiversity.  And this is where large heterogeneous landscapes play a crucial role in biodiversity here in Maine, as varied carnivores may have diverse landscape needs, and require connectivity in order to disperse and share their genetics.

In conserving these landscapes, we need to minimize the gradients between reserves and human use, and humans need to be integrated into the process.  The ongoing efforts to preserve the large landscapes of our farms here in Maine, is an example of this.  It is known that large carnivores generally do not need pristine conditions, as many of us have come to see, living with Coyote. But what truly effects their distribution and abundance is security from human conflict and freedom from human exploitation.  And this is the challenge for our generation. In order for this to happen, the support from a better educated public will be required.

But often, despite an intellectual understanding of Nature’s plan in creating the predator prey relationship, many humans have great difficulty accepting it. It is good to ask ourselves  “Why?”  Do we not see the world and all its life through the windows of our understanding, through the perspective of our human experience that often separates us from nature?  And yes, we do.  And in doing so we may very easily distort the true reality.

In the wisdom of Nature, the predator is not separate from their prey, they are a single organism, that is dynamic and ever adapting to life on earth.  Through our perspective we have separated them, and thus have lost sight of how these two beings create the whole.  So I would encourage you to practice looking through the eyes of Nature.  Unsurprisingly, our very young children do.

Much, much more…

The above information regarding coyote ecology is just skimming the surface. There is so much more to the complexity of their lives and their relationship with the land and other wildlife.  Please refer to the reading list and journal article section of our website to learn more.