Niche Differentiation

The term niche differentiation (synonymous with niche segregation, niche separation and niche partitioning), as it applies to the field of ecology, refers to the process by which natural selection drives competing species into different patterns of resource use or different niches. This process allows two species to partition certain resources so that one species does not out-compete the other as dictated by the competitive exclusion principle; thus, coexistence is obtained through the differentiation of their ecological niches. Niche partitioning may not occur if there is sufficient geographic and ecological space for organisms to expand into.

Niche differentiation is a process which occurs through several different modes and on multiple temporal and spatial scales. In most cases, niche differentiation has created a relationship between two species where current competition is small or non-existent. Because of this, the presence of niche differentiation can be methodologically difficult to prove or disprove. The lack of evidence for current or past competition can blur the line between 1) two competitive species differentiating their niches to allow coexistence as opposed to 2) two non-competing species which occupy similar niches. It is important to keep in mind that niche differentiation and inter-specific competition cannot always be considered linked.

As an example of resource partitioning, seven Anolis lizards in tropical rainforest share common food needs — mainly insects. They avoid competition by occupying different sections of the rainforest. Some live on the leaf litter floor while others live on shady branches, thereby avoiding competition over food in those sections of the forest. All resources are subject to partitioning, for example; space, food, nesting sites. This minimizes competition between similar species.