Herbivory is generally overlooked as a factor influencing the viability of endangered plant populations in western North American grasslands. I conducted experiments to determine the effects of terrestrial mollusc herbivory for survival of a federally endangered, annual forb, Holocarpha macradenia (Santa Cruz tarplant), in California's coastal prairie. In addition, I utilized litter removal and clipping regimes from a continuing study of site-specific responses to evaluate the relationship between herbivory rates from terrestrial molluscs and disturbance regimes. I planted seedlings of H. macradenia into copper bordered quadrats that excluded molluscs and into non-copper bordered controls at two sites in California's coastal prairie. Three treatment regimes of vegetation clipping and litter removal were utilized. Herbivory damage was assessed using an ordinal scale every two weeks throughout the rainy season. Molluscs were also trapped and identified. Herbivory amounts were significantly less when molluscs were excluded from plots for all disturbance regimes; however, there was no significant difference in herbivory levels between the disturbance regimes. A significant amount of invertebrate herbivory on H. macradenia was by the non-native slug, Deroceras reticulatum (grey garden slug), and this herbivory significantly affected the survivability of H. macradenia seedlings in California coastal prairie.

Fuel treatments to reduce fire danger are being applied to public lands throughout the western United States, affecting significant acreage at considerable expense. This study compares the short term effects of two fuel treatment methods, shrub mastication and “hand cut, pile, and burn” (HPB), on chaparral communities in southwestern Oregon. Ceanothus cuneatus dominated the study sites where permanent paired plots were established on either side of treatment-control boundaries. Over a two year period, we recorded all vascular plant species within each treatment or control plot, along with an abundance class for each species. The effects of treatment on species composition and abundance of forbs and graminoids, overall as well as by plant trait group, were surprisingly small. Time since treatment, 1 yr or 2 yr, had a stronger effect on species composition than did treatment method. Species abundance and richness were greater in the first year after treatments than in the second year or in controls. In the second year, after both types of treatments, species abundance and richness were reduced, while after mastication treatment, these measures were lower than in control areas. The HPB treatment had a greater effect on plant communities than did mastication, due, at least in part, to the presence of fire rings from burned piles. Compared to their surrounding treated plots, fire rings had greater proportions of both annuals (95% versus 71%) and introduced weeds (35% versus 21%) in the second year after treatment. Ceanothus germination was stimulated in fire rings but also occurred in most plots, including controls. Both types of treated areas had more Ceanothus seedlings than their controls. Short term evidence suggests that the HPB treatment may lead to an increase in weedy and exotic species and the mastication treatment may reduce species diversity. The HPB treatment may also increase native species diversity by allowing fire-cued species to establish. Additional monitoring over time is needed to assess longer term treatment consequences for these northern chaparral communities.

In response to conservation concerns, the reproductive biology of the San Fernando Valley Spineflower was investigated, focusing on pollination interactions and seed germination. Pollination by a variety of aerial visitors, as well as autogamy (a facultative selfer, showing about 25% selfing), appear to contribute significantly to fruit/seed set. There was a significant correlation between the numerous different floral visitors (many went uncollected) and the invertebrate fauna in the immediately surrounding coastal sage scrub community indicating that this taxon is visited by a substantial variety of potential pollinators and is probably not pollinator-limited. Although there were many potential pollinators, only six species, including three species of ants, made up the vast majority of visits to the flowers at the two study sites. Many of the invertebrate visitors to the flowers of the San Fernando Valley Spineflower exhibited a high rate of constancy. An overall generalist strategy is suggested. Seed set was high and a germination rate of over 70% occurred without pre-treatment.

The relationship between Streptanthus vernalis and Streptanthus barbiger (including the taxonomic synonym Mesoreanthus fallax) is examined. Morphological and allozyme comparisons show that the species are unrelated.

The Second International Phytogeographical Excursion of 1913 was initiated by University of Chicago's Henry Cowles and represented the first international party of plant geographers to visit the United States. Among the twelve Europeans who participated were Cambridge University's Alfred Tansley, first president of the British Ecological Society (and later to coin the word “ecosystem”), and Adolf Engler, taxonomist and biogeographer of Berlin's Royal Botanical Gardens. Arriving in New York City at the end of July, the excursionists (nicknamed the “Phyto-jogs” by Willis Jepson) traveled by train to the West Coast, with stops in a variety of ecosystems. After arriving at San Francisco Bay from the Pacific Northwest in early September, the Phyto-jogs, guided by University of California's Jepson, proceeded to Yosemite National Park for field trips and a famous group photograph among Mariposa Grove's Giant Sequoias. On September 12 in Oakland, several of the European scientists presented major lectures at the California Botanical Society's first annual banquet. The following days included visits to sites of local interest, including Burbank's experimental garden, Mount Tamalpais and Muir Woods with Alice Eastwood, and the Carnegie Institution's Coastal Laboratory at Carmel. The last two days covered the California desert, including the Salton Sea, and Tucson's Carnegie Desert Laboratory within the Sonoran Desert. A year later Professor Tansley, reflecting on the phytogeographical diversity of America and the varied researches of its many energetic ecologists, wrote: “In that vast field of ecology America has secured a commanding position.”

I discovered evidence of extreme root proliferation by Eriogonum parvifolium following the recovery of skeletal remains of a large, radio-tracked snake buried in the sand dune environment at the Tijuana Estuary in San Diego, California. Located beneath an isolated E. parvifolium, the recovered remains were grossly entangled by a large number of roots generally absent from the adjacent soil. The apparent massive localized proliferation of roots suggests decomposition of the animal created a favorable soil mosaic readily utilized by the plant in an otherwise low nutrient environment.