SGER: Does Manipulation of Top Predators Lead to Rapid Shifts in the Structure of Ecological Communities?

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This SGER project would capitalize upon the imminent reintroduction of foxes to San Miguel Island, part of the Channel Islands off the coast of southern California. The Island Fox (Urocyon littoralis) was removed from San Miguel Island in 1998. Following fox removal, the native rodent population (consisting of a single Peromyscus species) has shown dramatic increases, attaining densities of over 900 mice per hectare - thirty times greater than densities on nearby Santa Cruz Island where fox are present. There is some evidence that the removal of foxes on San Miguel and the dramatic increase in their rodent prey led to rapid changes in the plant community. This SGER would allow the real-time tracking of the small mammal prey community on San Miguel in response to reintroduced foxes, with the immediate and longer term effects that foxes have on the plant community a central focus. Contrasts will include San Miguel before and after fox reintroduction, with San Nicolas Island where foxes have been present for at least 2000 years, and Santa Barbara Island where foxes have never been present (at least recently). The approach would be to use exclosures to manipulate predator and rodent access in order to quantify top-down influences on plant communities across islands with different predator histories as well as different contemporary predator activity (i.e. the reintroduction on San Miguel). The broader applications of the project are potentially quite large, especially considering that the Islands have hundreds of species of rare and endangered plants. Because the Park Service is responsible for oversight of the Channel Islands, there is an opportunity for outreach with Park volunteers, and some fairly unusual outlets for any results. The research would support a female graduate student.