Effects of coal dust on species composition of mosses and lichens in an arid environment

A wind-borne plume of coal dust has been deposited on the soil and vegetation next to a coal storage area at a power generation plant in Oregon (U.S.A.). Correlated with the deposition of coal dust were significantly increased soil temperatures, decreased pH, and increased moisture-holding properties. Some heavy metal concentrations were also higher on the plume. These differences are possibly responsible for the lower frequencies and diversity of lichen species on the plume. Moss diversity, frequency and percent cover are similar on and off the plume with the exception of Ceratodon purpureus. The increased cover of C. purpureus may be attributed to heavy metal tolerance on the plume.