Does a suitable habitat guarantee successful colonization?

Among 9 rocky intertidal cerithiid species of the Sinai coast of the Red Sea, only Cerithium scabridum has managed to traverse the length of the Suez Canal, as well as to colonize the Mediterranean. By comparing the degree of overlap, between the colonizer and each of the non-colonizing species, in the ranges of habitat space along the axes of several abiotic environmental gradients relevant to cerithiids, it was found that one of the non-colonizing species, C. caeruleum, is capable of both immigrating successfully through the Canal, and of finding a suitable habitat in the Mediterranean. Yet, although C. caeruleum did invade parts of the Suez Canal, it did not colonize the Mediterranean. Hence, the availability of a suitable habitat in an area open for colonization need not necessarily guarantee successful colonization.-Authors