By Chelsea Jandreau
There are plenty of words used in our general vocabulary that also get used by the scientific community. Sometimes those words originally have a very scientific definition while others have been co-opted by science at some point in history to have a similar, if not slightly more specific meaning. Science often asks you to be a little more specific.
When you lack some of that specificity, it can change the question or the answer. When I ask a question that isn’t quite precise enough, it can change the trajectory of a discussion, as it did with a particular group of fourth graders.
Now the question I asked this group of fourth graders wasn’t exactly wrong; I just accidentally omitted a word that changed the responses. I began by asking the students what they knew about bears. I got a flurry of hands and responses. However, a couple of those responses were not about the black bear, which was the bear I was intending to talk about, but instead were about polar bears. This was entirely my error. Even though I meant black bears, they were simply responding to the prompt, which was just about bears in general.
Black bears and polar bears, while being closely related, have some distinct and important differences in their habitats, diets, and physical adaptations. Many of the differences exist because of their geographic location, but they still each have a unique impact on their respective ecosystems. Throughout generations, they have carved out a niche that allows them to survive in that area.
When someone uses the word niche in regard to humans, they usually say that someone has found or is looking for their niche. The idea is that this person has found the school, job or place they are best suited to be or they have found the thing that they are best at.
Ecologically, a niche refers to the role a particular species plays in its ecosystem. It encompasses the interactions between organisms and non-living factors such as soil and water, as well as the effects it has on its surrounding environment. An organisms’ niche is where it functions best within its immediate environment to help the survival of its species and decrease competition.
Our previously mentioned bears have different niches and play different roles in their ecosystem. The American Black Bear lives across North America and although it is omnivorous, it mostly eats plants and insects. The meat it costumes ranges from fish to carrion, but it rarely chases down its prey. They spend most of their winter in dens dormant due to a lack of food. Polar bears live in the Arctic Circle and while also omnivorous, the majority of their diet is meat. They hunt their prey, including seals, and because they have food available all year long, they do not go dormant during any particular season. These differences allow them to fit in a niche that works for their ecosystem. Just because they are both bears, that does not mean they could survive in each other’s place.
Black bears and polar bears occupy different geographical areas, so if you just compare those two species without regard to where they live, the niches they occupy have obvious differences. However, when you look at animals that actually live in the same area, such as a deciduous forest, it gets a little trickier to figure out each species’ niche. An earthworm is definitely different from a coyote, but what about a squirrel and a chipmunk?
Tree squirrels and chipmunks are both members of the same family, and are often confused for each other.
Physically, tree squirrels are generally the ones with longer, bushy tails, while chipmunks have skinnier tails and stripes on their body. Even though they look similar enough to get confused, they still have their individual niches within the forest. There is plenty of overlap in diet and habitat. They both eat nuts, seeds, berries, fungi and insects, but even with the similarities, there needs to be some variation in each organism’s niche. They may eat different sized foods and search in different locations. Both store food for the winter and spend less time foraging, but chipmunks burrow in an underground den and squirrels make their winter homes in trees.
They may be sharing food sources with each other in addition to other animals, but this only works as long as there are enough resources to go around. All organisms require certain resources in varying amounts, and this variation, no matter how small, decreases the competition required for survival. If two organisms occupy exactly the same niche, it is likely one would eventually outcompete the other. The more available resources and thus the greater number of differing relationships to the living and nonliving resources in their environment, the greater the biodiversity of an area.
This concept of niches is in turn an important part of a larger concept known as community ecology. This is the study and exploration of how biological communities interact, compete and generally function, and it is becoming increasingly important as climates and habitats continue to change. The definition of an ecological niche has evolved over time, but it remains something that can help scientists understand the resiliency of different ecosystems and how organisms have and will continue to respond to environmental changes in the future.
Audubon Community Nature Center builds and nurtures connections between people and nature. ACNC is located just east of Route 62 between Warren and Jamestown. The trails are open from dawn to dusk as is Liberty, the Bald Eagle. The Nature Center is open, including restrooms, the Blue Heron Gift Shop, Indoor Nature Play Area and most exhibits. More information can be found online at auduboncnc.org or by calling (716) 569-2345.