Because invasive annual grasses can strongly influence soil resource availability and disturbance regimes to favor their own persistence, there is a great need to understand the interrelationships among invasive plant abundance, resource availability, and desirable species prominence. These interrelationships were studied in two salt desert sites where the local abundance of downy brome (Bromus tectorum L.) varied spatially and increased more than 12-fold over a 3-yr period. We measured downy brome percentage cover, resource availability, and soil chemical and physical properties within 112 plots per site and found significant negative associations between downy brome abundance and both soil water content (P < 0.05; r = −0.27 to −0.49) and nitrate accumulation (P < 0.05; r = −0.34 to −0.45), which corroborated with the direction and strength of multivariate factor loadings assessed with principal component analysis...