Small mammals are vital to the health of many of the Reserve’s ecosystems. They are important food for raptors, reptiles, and larger mammals. By eating seeds, rodents help control invasive plants, and their population trends can signal possible invasive species proliferation. They are also good indicators of habitat quality; studies have shown that small mammal diversity is highest in undisturbed areas with abundant native vegetation and lowest in fragmented or heavily invaded sites. Thus, trends in composition and abundance of small mammals across the EHA Study Area could provide an indication of the impacts of disturbance and fragmentation on the health of the conserved habitats and species, and could help provide direction for management actions.
The endangered Pacific pocket mouse (Perognathus longimembris pacificus) and the San Diego desert woodrat (Neotoma lepida intermedia) are two of the sensitive small-mammal species the Natural Communities Conservation Plan/Habitat Conservation Plan conservation strategy is intended to benefit, but at least 13 native small mammal species play important roles in maintaining balance across the Reserve’s habitat mosaic. However, other than directed pocket mouse surveys, few efforts have been made to monitor small-mammal diversity and abundance within the Ecological Health Assessment Study Area. Trapping surveys would provide baselines for understanding how small-mammal community composition responds to various ecological disturbances within the conserved land network (e.g., grazing, invasive plant species, fire, drought), which should facilitate targeted management of the EHA Study Area’s native species and habitats.
