Powell Center Working Group Project Information
Completing the dryland puzzle: creating a predictive framework for biological soil crust function and response to climate change
Matthew A Bowker (Northern Arizona University)
Nichole Barger (University of Colorado Boulder)
Anita J Antoninka (Northern Arizona University)
Jayne Belnap (Canyonlands Field Station, SBSC)
Award Date: 2017
Drylands are integral to the Earth system and the present and future of human society. Drylands encompass more than 40% of the terrestrial landmass and support 34% of the world’s human population. Biocrusts are the “living skin” of Earth’s drylands, sometimes dominating the ground cover and figuring prominently in ecosystem structure and function. Biocrusts are a biological aggregate of cyanobacteria, fungi, algae, lichens and mosses in the surface millimeters of soil. By aggregating soil, biocrusts make sediment less erodible. They also strongly influence the water runoff-infiltration balance. In some ecosystems they generate runoff, whereas in other systems they enhance water capture. Vascular plant germination, establishment, and nutrient status are also affected by biocrusts. For some plants, biocrusts may reduce germination, while plants that do germinate in biocrusts may experience enhanced growth rates and access to nutrients. The manner in which biocrusts perform these functions differs among ecosystems; we currently lack the synthetic work to generalize the reasons why. We have assembled a team of dryland experts spanning a variety of disciplines to address two broad questions: 1) What factors control the degree to which biocrusts contribute to key ecosystem functions (vascular plant success, water capture and redirection, and soil stability)?; and 2) How is global change likely to affect the function, distribution and diversity of biocrusts?