Biology – Biodiversity | e-Consult

A niche is the role and position a species has in its environment – how it lives, what it eats, when it's active, and how it interacts with other species. It encompasses all the biotic and abiotic factors that influence a species' survival and reproduction.

Fundamental niche refers to the full range of environmental conditions and resources a species *could* potentially occupy and utilize. It's the theoretical niche without considering competition or other limiting factors.

Realized niche is the actual portion of the fundamental niche that a species occupies in the presence of competition, predation, and other limiting factors. It's the niche that a species *actually* uses.

Differences between the fundamental and realized niches arise due to:

• Competition: Other species may prevent a species from accessing resources it could otherwise use.
• Predation: Predators can limit the distribution of a species.
• Parasitism: Parasites can weaken a species and restrict its range.
• Other abiotic factors: Limited access to water, sunlight, or suitable habitat can restrict a species' niche.