Niches

Generalist species can use a relatively broad range of resources or conditions. Specialists have narrower requirements. These terms describe niche breadth, rather than simply the size of a species’ territory. Both are vulnerable in their own ways. It is not always better to be one or the other but knowing which you are can help you strategize your continued survival.

The ecological niche of a species refers to the role it plays in the ecosystem in which it is found. Every species in an ecosystem has a niche. A species’ niche includes everything that affects its ability to reproduce and survive. For example, the amount of water and sunlight it needs, the temperatures it can tolerate, and how much space it requires to live are all part of its niche and are called abiotic factors, meaning the non-living aspects of an ecosystem.

Generalist organisms have a broad niche. Those with a broad niche can survive in a variety of places as they are usually capable of eating different foods and are able to tolerate different environmental conditions. This usually means that they can protect themselves from different predators, tolerate a range of temperatures and moisture conditions, and eat a wide variety of meats and plants and other foods. That flexibility can help generalists cope with change, although they remain vulnerable to conditions outside their tolerances. Such organisms include cockroaches, rats, raccoons, and humans.

« Generalists can survive and flourish in just about any setting. But specialists tend to be much less comfortable with habitat change.»

Peter Ungar1

Specialist organisms, on the other hand, have a very distinct set of roles in the ecosystem. For example, some specialists can only survive in specific locations or eat particular foods. They are more prone to extinction. Specialists, therefore, have a harder time maintaining large population sizes because it is common for land conditions to change and for resources such as foods to diminish over time. However, in places like tropical rain forests with stable environmental conditions, it is advantageous to be a specialist because they tend to have fewer competitors, whereas most of the generalists must compete against each other.

Another reason why specialists do well under stable environmental conditions is that they possess mechanisms that allow them to not only survive but thrive in those particular locations. For example, some animals can eat foods that are toxic to other animals, and tiger salamanders have developed the unique ability to seek out and breed only in ponds without fish so their larvae will not be eaten. This means that they will thrive in environments full of their particular requirements but do poorly when they are placed in environments lacking these. Think of koalas and their particular diet of eucalyptus, or the giant panda struggling to avoid extinction in part because its specialized diet consisting mostly of bamboo makes it unable to adapt to changing environmental conditions.

« The generalist method is adequate if stakes are low, but increasing specialization is often mandated when the stakes—the standards of performance in competition—are high. »

Geerat Vermeij2

Social animals allow for divisions of labor within their groups, such as having defense specialists. For humans, the species may be a generalist, but as individuals we strongly specialize.