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Seed Banks and Prescribed Burns: Factors Affecting Successful Control of French Broom and Restoration of Native Communities in Coastal California GrasslandsEPA Grant Number: U915607
Title: Seed Banks and Prescribed Burns: Factors Affecting Successful Control of French Broom and Restoration of Native Communities in Coastal California Grasslands
Investigators: Alexander, Janice M.
Institution: University of California - Berkeley
EPA Project Officer: Broadway, Virginia
Project Period: August 1, 1999 through August 1, 2002
Project Amount: $52,854
RFA: STAR Graduate Fellowships (1999) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology and Ecosystems
French broom (Genista monspessulana) is an invasive shrub from Europe now abundant in California. Once established, broom plants form dense, practically monotypic stands that displace grassland species. In an effort to restore native plant communities and reduce fuel loads, land managers in Marin County, CA, remove French broom through cutting, pulling, and prescribed burning. To completely control broom, however, it is necessary to remove both living biomass and the seed bank. The objective of this research project is to assess management efforts with reference to the broom seed bank, the native seed bank, and the success of revegetation of native plants. The investigator is building a simple model demonstrating the dynamics of native and broom seed banks under different aged broom stands. This research also investigates how prescribed fires influence emergence and persistence of the seed banks, and the revegetation potential of post-broom communities.
The community composition of areas that had received different types of management treatments will be surveyed to assess which environmental factors are important in effectively controlling broom and restoring native plants. The seed bank will be sampled within discrete, established French broom stands in oak woodland understory and coastal grassland habitats in Marin County. Within a broom patch, soil samples will be taken along a transect, and the density of broom plants will be recorded. Soil cores will be spread out to germinate in a latthouse. The number of germinating seeds of all species will be counted, as well as the number of dormant and dead broom seeds. The age of the stands will be estimated by counting growth rings of the largest broom individuals.
This research will provide information to aid managers in restoring native plant communities after the removal of French broom.