Canyonlands National Park - Lichens

There is a great deal of exposed rock in Canyonlands, and much of it is covered by lichens. Lichens usually colonize north-facing surfaces since reduced solar radiation is an advantage for many organisms in the desert. Lichens also grow on healthy, mature cryptobiotic soil crust, and occasionally on live or dead plant material. Many species of lichen are found in Canyonlands.

A lichen is actually a simple community of at least two organisms, namely fungi with green algae or cyanobacteria, though sometimes with both. The lichen structure is more elaborate and durable than either fungi or algae alone. Green algae and cyanobacteria manufacture food via photosynthesis, while fungi provide a buffer against weather and are capable of extracting nutrients from soil and rock.

Many plants benefit from the presence of lichens. The cyanobacterial component of lichens can transform atmospheric nitrogen (unusable to most organisms) into a form that is an essential nutrient for life. This is especially important in desert ecosystems, where lack of nitrogen is known to limit productivity.