What is an ecological niche?

What is an ecological niche? This is a question you'll probably encounter if you study primatology/ecology/zoology/etc. If I search for "niche" in the dictionary that comes with my Mac, I find that niche is "a position or role taken by a kind of organism within its community."  But what does that mean? Niche is a concept I found some students in the introduction to anthropology course struggled with, so let's take a closer look.

Some factors that contribute to niche

A niche is more than just the environment an organism lives in, it really is the role the organism takes (so the dictionary definition isn't entirely bad). It's not just where an animal lives, but the animal's behavior, what time of day its active in its environment, what foods it prefers most to eat, what foods it can eat when preferred foods aren't available, and so forth. How an animal responds to resources is part of its niche as is how it may respond to any predators. An animal's life history, or the sequence of events from birth to death related to reproduction, is also part of its niche. Many animals occupy the same environment. You could sit very, very quietly in a tropical forest for a couple of hours and see multiple animals exploiting a single fruiting tree.

If we just talk about primates for a minute, we may find one species of primate eats leaves from this tree. A second primate species consumes the ripe fruit on the tree during the day. A third species of primate ignores the fruit entirely, is only active at night, and instead hunts for insects and small reptiles on this tree.

Fundamental vs realized niche

This is an over simplified example though because a niche really is more than just diet or just habitat. Niches are complex. The actual or realized niche of a species may very well be entirely different from its fundamental niche, or the entire role/area a species could utilize in its niche if free from limitations. For example, while a primate that lives mainly on leaves may love to eat fruit, other competitors may prevent that primate from doing so. Thus, the realized niche does not include fruit but the fundamental niche does, because the primate is capable of foraging and feeding on that fruit. Keeping in mind the difference between realized and fundamental niche, different populations of the same species may have different realized niches. Let's say there are two populations of the same primate species but they live in slightly different patches of forest. Depending on the predators and conditions in each of those two forests, the same species may be able to exploit resources differently or have slightly different behavioral patterns because of lower predation rates in one forest compared to the other. Thus, the realized niches might differ.


Food for thought: I'd say humans have one of the most flexible and largest ecological niches of all species. Would you agree?

Here's a cool article about the first visualization of an ecological niche. Check it out!