Experimental prediction: Comparing competitive exclusion with niche differentiation
Connell’s results led him to conclude that Chthamalus’ realized niche is smaller than its fundamental niche because of interspecific competition with Balanus. But what if competitive exclusion were not the explanation? What if Chthamalus’ and Balanus’ respective niches were a result of niche differentiation instead? Niche differentiation occurs when two species with overlapping niches change over time in a way that reduces their niche overlap, and thus reduces their competition for resources.
The rock below represents step 3 of Connell’s experimental procedure (see Part A) after he removed Balanus from one half of each transplanted rock.
Predict how the outcome of Connell’s experiment would be different in this hypothetical scenario in which niche differentiation — not competitive exclusion — is the reason for Chthamalus’ limited niche.
Drag the images of the left half of the rock (white) and right half of the rock (blue) to indicate which barnacle species (if any) would be present at the end of the summer if niche differentiation had occurred between Chthamalus and Balanus