Expanding the invasion footprint: Ventenata dubia and relationships to wildfire, environment, and plant communities in the Blue Mountains of the Inland Northwest, USA
Ventenata dubia was most abundant in sparsely vegetated, basalt-derived rocky scablands interspersed throughout the forested landscape. Plant communities most heavily invaded by V. dubia were largely uninvaded by other non-native annual grasses. Ventenata dubia was abundant in both unburned and burned areas, but negative relationships between V. dubia cover and community diversity were stronger in burned plots, where keystone sagebrush species were largely absent after fire. Ventenata dubia is expanding the overall invasion footprint into previously uninvaded communities. Burning may exacerbate negative relationships between V. dubia and species richness, evenness, and functional diversity, including in communities that historically rarely burned. Understanding the drivers and impacts of the V. dubia invasion and recognizing how these differ from other annual grass invasions may provide insight into mechanisms of community invasibility, grass-fire feedbacks, and aid the development of species-specific management plans.