The introduction and spread of non-native species is a global conservation challenge. In the Pacific Northwest, grasslands have been shown to be especially vulnerable to this threat. While the upland prairie habitats of the Zumwalt Prairie are still mostly dominated by native plant species, invasives have gained a foothold in some areas and pose a threat to many species and habitats of conservation importance. Non-native plants have been introduced to the Zumwalt Prairie through crop agriculture, livestock, vehicles, and other means.  While some species, for example sulfur (also "sulphur") cinquefoil (Potentilla recta), are mostly confined to old fields, others, such as common crupina, appear able to invade even undisturbed bunchgrass prairie. Invasive species may harm biodiversity through direct competition with natives or by changing key ecosystem processes (e.g., soil erosion rates or fire frequencies).

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• Apilot project to improve the ecological condition of old fields on the Zumwalt Prairie Preserve (2010)

• Inventory of Whitetop (Cardaria draba) on the Zumwalt Prairie Preserve (2010)

• Monitoring common crupina (Crupina vulgaris) in Trail Creek Canyon on the Zumwalt Prairie Preserve (2009), (2010) (2011)
• Mapping and monitoring meadow hawkweed (Hieracium caespitosum) on the Zumwalt Prairie Preserve (2006-9)(2006-10)
• Mapping and monitoring sulfur cinquefoil (Potentilla recta) on the Zumwalt Prairie Preserve (2006-9),(2006-10) 
• Mapping and monitoring sulfur cinquefoil (Potentilla recta) on the Clear Lake Ridge Preserve (2009) ,(2009-10) 
• An Inventory of Yellow Starthistle (Centaurea solstitialis) on the Zumwalt Prairie Preserve (2009),(2010) 
• Monitoring of common bugloss (Anchusa officinalis) on the Zumwalt Prairie Preserve (2006-2008),(2009),(2010), (2011)
• Inventory of common crupina (Crupina vulgaris) in Trail Creek on the Zumwalt Prairie Preserve (2008),  
• Mapping and monitoring the abundance of noxious weeds on the Prairie Uplands of the Zumwalt Prairie Preserve (2008),(2007),(2006)
• Characterization of randomly selected burr chervil (Anthriscus caucalis) sites along Camp Creek (2006)
• Mapping of sulfur cinquefoil (Potentilla recta) in Crested Wheat Pasture on the Zumwalt Prairie Preserve (2004)
• Effect of herbicide Transline® on the abundance of meadow hawkweed (Hieracium caespitosum) on the Zumwalt Prairie (2004)
• Effect of herbicide Tordon® on the abundance of the sulfur cinquefoil (Potentilla recta) on the Zumwalt Prairie (2004)
• A study to examine the efficacy of field mapping meadow hawkweed (Hieracium caespitosum)(2004)