Productivity and flowering of winter ephemerals in relation to Sonoran Desert shrubs

Ephemeral plant biomass and density on a Sonoran Desert hill near Cave Creek, Arizona, vary relative to shrub canopy type and shrub density. Higher shrub density associated with increased elevation appears to decrease both ephemeral biomass productivity and density, while ephemeral growth is enhanced under a shrub canopy if it is not too dense or low-hanging. Phenology of ephemerals on the desert study site shows early cool-season germination, low tolerance to heat, and early flowering when compared to shrubs and succulents in the same area.