The University of California Natural Reserve System. The mission of the Natural Reserve System is to contribute to the understanding and wise management of the Earth and its natural systems by supporting university-level teaching, research, and public service at protected natural areas throughout California.

Common Ground at the Donald and Sylvia McLaughlin Reserve The idea of creating a reserve on McLaughlin Mine property originated with Homestake’s visionary environmental manager, Ray Krauss. In 1985, when the mine had just begun operation, Ray approached UC about the possibility of creating a reserve to be incorporated into the UC Natural Reserve System. In 1992, the first steps were taken to create a 300-acre reserve in this complex and intriguing serpentine landscape. Through 2002, students, researchers and miners respectfully coexisted on the reserve.

In 2003, with the last ounce of gold poured, Homestake and the University signed an agreement expanding the reserve to 6800 acres, with the Land Trust of Napa County holding a conservation easement on the property. Homestake (now a subsidiary of Barrick Gold) will have an obvious continued presence as they conduct post-mine monitoring and reclamation.

The McLaughlin Mine has been widely recognized by both environmental and mining organizations for its rigorous environmental monitoring and its innovative restoration and land management. The Donald and Sylvia McLaughlin Natural Reserve will continue the tradition of exemplary stewardship on this unique landscape.

Using the Mine to Understand Invasion Biology and Restoration, during mining operations, millions of cubic yards of rock and soil were moved to reach the gold ore. Graduate students in the NSF Biological Invasions Integrative Graduate Education and Research Traineeship (IGERT) are using these mountains of transplanted soil as an experimental site to test the role of propagule supply (numbers of seeds and numbers of times they are introduced) in determining the success of invasions by common weeds such as European mustard. There are also plans to use the mine’s revegetation program as an opportunity to study various aspects of restoration ecology.

The Natural Reserves managed by UC Davis are a cornerstone of UC Davis’s excellence in the environmental fields. They serve as outdoor laboratories with access to high-quality natural habitats, well-maintained infrastructure, and long-term data bases. In the past four years we have built them into a flourishing academic facility that has hosted 149 research projects (about half by graduate students) and 144 courses with 2415 students. The activities and accomplishments at each reserve are detailed in Part II of this report. Our goals for the next five years are to keep the reserves on their present trajectory of success, and to maintain the investment by the campus in both their physical facilities and the academic programs they support.

Invasion by exotic species is a major threat to global diversity. The invasion of native perennial grasslands in California by annual species from the southern Mediterranean region is one of the most dramatic invasions worldwide. As a result of this invasion, native species are often restricted to low-fertility, marginal habitat. An understanding of the mechanisms that prevent the recolonization of the more fertile sites by native species is critical to determining the prospects for conservation and restoration of the native flora. We present the results of a five-year experiment in which we used seeding, burning, and mowing treatments to investigate the mechanisms that constrain native annuals to the marginal habitat of a Californian serpentine grassland. The abundance and richness of native species declined with increasing soil fertility, and there was no effect of burning or mowing on native abundance or richness in the absence of seeding. We found that native annual forbs were strongly seed limited; a single seeding increased abundance of native forbs even in the presence of high densities of exotic species, and this effect was generally discernable after four years. These results suggest that current levels of dominance by exotic species are not simply the result of direct competitive interactions, and that seeding of native species is necessary and may be sufficient to create viable populations of native annual species in areas that are currently dominated by exotic species.