The ecological niche is “the sum total of the adaptations of an organismic unit, or as all of the various ways in which a given organismic unit conforms to its particular environment” (Pianka 1999). In other words, niche refers to the functional position of an organism in its environment, including the habitat where it lives, the time that it is active, and the resources it uses.
In environmental studies, understanding how different organisms relate to each other and the environment is critical in seeing how different parts of the ecological system compete, supplement, or are central to its function. For example, the disappearance of honeybees may mean less bee stings, but the loss of the functional niche of bees (pollination of crops) spells disaster for farmers. Ecological niches help us see overlap, competition, and breadth (specialization vs. generalization) for different species in the same ecology.
Chapter 13 “The Ecological Niche” from Pianka 1999
Ecological Niche (Science Daily)