Don’t Bust the Crust: Biocrust Survival in Arid Lands across the West

photo by Sophie Poukish

photo by Sophie Poukish

Dispatch by Hannah Trettenero

In Castle Valley, Utah with red rock formations stark against blue skies, botanist and Utah Forests Program Director for the Grand Canyon Trust, Mary O’Brien exclaims, “Don’t bust the crust!” This particular crust is biological soil crust or biocrust. To the unassuming eye, the communities of bacteria, lichens, and mosses that partner together to form biocrust may appear to be inanimate soil. A magnified look reveals biocrust forms ranging from black bumps to pink pentagons to yellow cauliflowers. Biocrust is a layer of living organisms that cover the upper layer of soil in semi-arid and arid lands. Biocrust forms through a successional process beginning with colonization of bare ground by lighter crusts such as microscopic cyanobacteria, and culminating with colonization by darker crusts such as lichens or mosses. To arid ecosystems, these organisms are the modulating heartbeat, regulating essential ecosystem functions. Biocrust binds the soil together to form a crust, allowing plants to grow, contributing to soil fertility and regulating water cycle. Cyanobacteria facilitate nitrogen cycling while mosses and lichens fix carbon through photosynthesis.   

Public lands are mandated as spaces for the people. A large portion of public lands in the west are dry and arid, dependent on biocrust to flourish. Humans, tires, and animals habit these public lands, often trampling and destroying biocrust, unaware they are killing these compression sensitive unique life forms. Biocrust cannot fully form when disturbances such as compression impact its’ ability to progress from its early state to its’ late successional state. Dry lands currently cover 45% of terrestrial surface area in the world and continue to grow as the affects of climate change shape environments. In Moab, Utah scientists from across the globe congregate to attend the biennial International Workshop on Biological Soil Crusts. On the second day of the workshop, scientists focus on research specifically about the affects of climate change on biocrust formation and diversity. The ultimate goal of this second day is to create connections between the localized biocrust experiments occurring across the globe in order to better understand how climate change will affect arid landscapes on a global scale. The results of specific experiments suggest that increased droughts and altered precipitation patterns caused by climate change will intensify the decline of biocrust. On public lands in the west, biocrust is working against the destructive forces of human induced compression and human induced climate change. Biocrust can take hundreds of years to form but people have the capacity to crush it in seconds, killing the building block of their own public lands.