Niche overlap describes:
“Sharing of resources by two or more species” for niche overlap describes. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Habitat describes where an organism occurs; niche additionally describes how it obtains resources and affects or responds to other organisms. Distribution therefore provides evidence about a niche but is not identical to it. The remaining alternatives—“Complete separation of niches”, “Absence of competition”, “Expansion of niche breadth”—refer to different states, processes, o
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 13