Lysandra Pyle,  Alberta Biodiversity Monitoring Institute and Edward Bork, University of Alberta

Biological soil crusts are an understudied but integral component of rangeland vegetation in the Northern Great Plains. These cryptic communities of lycophytes, bryophytes, lichens, algae, and bacteria stabilize prairie soils, fix both carbon and nitrogen, retain soil moisture, and influence vascular plant community dynamics. The importance of biological soil crusts will be discussed in the context of common rangeland plant community types, rangeland management, soil and rangeland health. Further, data will be presented from a case study examining the impacts of oil and gas infrastructure on mixed grass prairie vascular plant cover, germinable soil seed bank, and biological soil crusts at 18 pipeline sites in southeast Alberta. We measured the impacts of pipelines on prairie vegetation along a distance gradient up to 55 m from trench edges. Biological soil crusts are sensitive to disturbance and recover slowly. Importantly, their soil cover influences seed bank formation, seedling recruitment, serving a role in rangeland vegetation assemblages and invasive species establishment. This has implications for plant communities recovering from disturbance.