In my attempt to lock out the NHL, we will be looking into an ecological concept that has fascinated me for years: The concept of Trophic Cascades. Initially I researched this topic in the 3rd year of Undergrad in an Ecology class and ever since I always love thinking about and researching them.
Let's start at the beginning with a standard, non-complex ecological system or cycle. Remember the circle of life from The Lion King? So turns out, there pretty much is a circle of life. The Sun is the ever lasting source of energy, and provides the energy that plants need to produce Glucose and grow. Herbivores then feed on this food, transferring the energy. Herbivores get fed up by predators, which get fed upon by bigger predators, etc. Then animals will excrete the waste, or die and decompose. These nutrients are then reabsorbed into the plants and you have yourself back at the beginning of the cycle.
Now let's set up a hypothetical ecological system. We will have our plant (grains), our herbivore (field mouse), our predator (feral cat) and an apex predator or the top predator (mountain lion). In a vertical representation it would look like this:
That is our simple, Trophic Cascade, but what does this mean? Essentially it is read from the top to the bottom. Because Mountain Lions are the apex predators, they really have nothing that suppresses their numbers. They eat the Feral Cats which suppresses the numbers of the Feral Cats. Because there are low numbers of Feral Cats, there are large numbers of Field Mice and because there are large numbers of Field Mice, then there are low numbers of Grains. It looks like this:
Mountain Lion - High
Feral Cat - Low
Field Mouse - High
Grains - Low
Typically, like many systems, when part of this system is removed, you see a domino effect. Let's introduce a new element into the system, humans. Turns out, Mountain Lions are now a hot commodity and Mountain Lions are being hunted. Now our system looks like this:
With this introduction, now Humans are the apex predator, suppressing the Mountain Lion numbers. This allows the Feral Cat numbers to rise, which causes the Field Mice numbers to fall, and the Grain numbers to rise, looking like this:
Human - High
Mountain Lion - Low
Feral Cat - High
Field Mouse - Low
Grains - High
Just like that, the addition of one predator completely changes the entire ecological make up of a habitat. Factor in multiple predators, herbivores, omnivores, different types of fauna and microorganisms and you have yourself one complex Trophic Cascade.
I hope you have enjoyed your ride through one of my favorite ecological concepts. Feel free to ask any questions, and although I am not an expert, I will do my best to answer any questions you may have.