28.6
An ecological niche describes the role of an organism within its environment. The niche includes all the biotic, or living, and abiotic, or nonliving, resources and conditions that the organism uses.
For example, the niche of a hare includes abiotic factors such as the climate where it can survive and the terrain that provides shelter and protection from predators.
Biotic factors include other hares with which it interacts, the plants it eats, and the predators that feed on it.
A fundamental niche is the full range of resources and environmental conditions that an organism could use. A realized niche is the narrower range of resources that a species actually uses.
Competition with other species often limits the size of the realized niche.
If competition from other species is reduced or removed, the species may begin to use more of the resources that it could potentially use. As a result, its realized niche can expand toward its fundamental niche.
While members of the same species often share some resources in the same area, two different species cannot occupy the same niche indefinitely. If they do, one would outcompete the other.
So how can similar species live in the same place without one driving the other out?
One way species avoid competition is by gradually dividing resources. This process is called resource partitioning. This division of limited resources allows species to coexist instead of competing directly.
Ecologically similar species may evolve to use different resources. They may also share the same resources but use them at different times or in different places.
A classic example of resource partitioning comes from Robert MacArthur's research on warbler species in the forests of New England.
MacArthur showed that although the warblers appear to use the same resources, live in the same trees, and consume the same insects, they actually occupy different areas of the trees.
This spatial partitioning of resources allows five species of warblers to coexist within the same trees.
Tutti gli organismi hanno una posizione all'interno di un ecosistema. L'insieme completo di fattori viventi e non viventi, tra cui le risorse alimenta…
Copyright © 2026 MyJoVE Corporation. Tutti i diritti riservati.