Barnacle niche expansion after competitor removal indicates:
Experimental removal of a competitor reveals whether biotic interactions restrict a species’ observed distribution. If a barnacle expands into additional intertidal space after its competitor is removed, the newly occupied zone was environmentally tolerable but previously inaccessible because of competition. That broader potential range belongs to the fundamental niche, whereas the restricted distribution observed with the competitor present is the realized niche. Thus the realized niche was smaller than the fundamental niche. Connell’s classic work on Scottish intertidal barnacles showed that
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 13
