Abstracts Biological Sciences

Biological Soil Crust Cover and Richness in Two Great Basin Vegetation Zones

by Stephanie M Freund

Biological soil crusts are communities of bacteria, microfungi, algae, lichens, and/or bryophytes that colonize the surfaces of soils where other vegetation is sparse. Soil crust communities are best known from the world’s arid and semiarid regions, including North America’s hot and cool deserts, where they aid in soil stabilization and aggregation, reduce erosion, and contribute to nutrient inputs in the soil. Although a significant body of work has emerged on soil crust function in arid and semiarid environments, there is still much to be learned about their geographical distributions within and across different vegetation communities. Sagebrush shrublands and pinyon-juniper woodlands are common communities in the central Great Basin, but this region is under-studied with respect to biological crust composition and distribution. I collected data on soil pH and the cover of plant functional groups and biological soil crusts in sagebrush and pinyon-juniper zones in the Wassuk Range of western Nevada. Regression models revealed that in the shrublands, soil crusts associate negatively to rock cover and positively to moderately dense shrub canopy. In the woodlands, ground-cover of rocks and woody litter have a negative association with soil crusts. Sagebrush and pinyon-juniper communities are facing many stressors and undergoing changes in structure. My results offer a possible starting point for assessing how the biological crusts in these habitats might respond to these changes based on their current distributional controls. Future research should further explore the response of biological crusts to trajectories of change in the central Great Basin ecoregion.