I think the conclusion would be that the fundamental and realized niches of B. balanoides are identical, but the fundamental and realized niches of C. stellatus are different.A barnarcle is a type of arthropod constituting the infraclass Cirripedia in the subphylum Crustecea, and thus related to crabs and lobsters. B. balanoides is a barnacle that attaches to rocks, especially during intertidal zones while C.stellatus is a species of acorn barnacle common on rocky shores in south West Eangland, Ireland, and Southern Europe.