Competition and niches are both factors which assist in shaping community structure and species distribution. These two ecological features are directly related to each other as resources located in overlapping niches are finite causing conflict and competition between intra- and inter-species.
A niche is representative of all the resources that a certain species needs in order to function properly, meaning that it can grow, reproduce and survive. There are two types of niches: fundamental and realized. An individual's fundamental niche is the full range of abiotic factors, biotic factors and resources that a species is capabe of using. However, often an individual can only function in its realized niche due to limiting factors such as competition. The realized niche is representative of the actual factors and resources a species has access to and thus, is only a portion of the fundamental niche.
Competition is an interaction which takes place between species and within species in which the outcome is positive for one individual and negative for the other. Often species have to compete with each other, especially when resources like food, water, shelter, and mates are limited. In ecology, an important concept outlining competition dyanamics in a community is the competitive exclusion principle. The competitive exclusion principle states that species which occupy the same fundamental niche are unable to exist indefinitely with each other since resources are limited, and this leads to competition between species for the same limiting resources. This is the coexistence conundrum.
Competition and niches are fundamental concepts in the study of ecology which are important for understanding how a community is structured. Realizing the niches that species occupy helps to illustrate why competition between certain species is evident and why the prominence of competition fluctuates through time.
Title Image Credit: Wikimedia Commons© BrainMass Inc. brainmass.com September 22, 2018, 3:09 am ad1c9bdddf