Explains biological soil crusts, organism-produced soil formations commonly found in semiarid and arid environments, with special reference to their biological composition, physical characteristics, and ecological significance.
Fact sheet on the need to protect biological soil crusts in the desert. These crusts are most of the soil surface in deserts not covered by green plants and are inhabited by cyanobacterium (blue-green algae) and other organisms useful to the ecosystem.
Description of bryophytes (mosses, liverworts, and hornworts) and lichens (dual organisms of a fungus and an alga or a cyanobacterium) that are part of forest ecosystems in the Pacific Northwest with information on habitat and conservation.
Web interface for a database of documented occurrences of lichens in units of the U. S. National Park System. The records were obtained from the scientific literature, from National Park Service reports, and from selected herbaria.