Moss species occupy strikingly narrow, even single-host, habitat niches.

Evidence

The boundaries that define where a particular species of moss calls home are often more narrow. Some are strictly aquatic, some are terrestrial. Epiphytic mosses restrict themselves to the branches of trees, but some epiphytes settle only on sugar maples and others only in the rotten knotholes of sugar maples growing on limestone. There are generalists that are ubiquitous on any patch of open soil, and specialists which favor the dirt tossed up by the diggings of pocket gophers in the tall-grass prairie. Some saxicolous (rock-dwelling) mosses can live on granite, others only on limestone and Mielichoferia only on rocks containing copper. — Robin Wall Kimmerer, Gathering Moss, 486

Categorization

• XREF: connects to: One moss species grows only on four-week-old deer droppings in July. — Robin Wall Kimmerer, Gathering Moss: A Natural and Cultural…, 487; Narrow habitat specialists must evolve directed, not windborne, dispersal — Robin Wall Kimmerer, Gathering Moss: A Natural and Cultural…, 498