Consumer movement among successional communities in relation to the rare, endemic plant Lassics lupine (Lupines constancei)

Succession may influence risk of consumption for plants by altering consumer abundance and movement. For rare plants occurring in early successional communities with low abundances of consumers, changes in vegetation composition may reduce population viability via increased consumption. I studied this process in Lassics lupine (Lupinus constancei), a rare forb endemic to a 1-km2 serpentine community on Mount Lassic and Red Lassic in Northern California. Pre-dispersal seed predation by small mammals such as deer mice (Peromyscus spp.) and chipmunks (Tamias spp.) led to a recent population decline, and succession of chaparral and forest communities may have facilitated this consumption. I used camera traps to identify potential consumers of Lassics lupine, a surrogate seed trial to determine if predation rates and risk differed among vegetation communities, and mark-recapture techniques to describe movements and spatial distributions of small mammals. Black-tailed jackrabbits (Lepus californicus) and California ground squirrels (Otospermophilus beecheyi) may play a larger role in the decline of Lassics lupine than previously thought, and surrogate seed predation rates varied marginally among communities. Multi-state models suggested that small mammal movement probability varied by community and was higher into and out of the serpentine community, the core of Lassics lupine habitat. Spatial mark-recapture models estimated higher densities of deer mice in the chaparral and higher elevation serpentine communities, compared to the forest and lower serpentine barrens. Consumers from adjacent successional communities may influence plant recruitment in different communities. This examination may yield insight into habitat-based management actions for rare plants such as Lassics lupine.