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Extramural Research

Grantee Research Project Results

Grantee Research Project Results

Seed Banks and Prescribed Burns: Factors Affecting Successful Control of French Broom and Restoration of Native Communities in Coastal California Grasslands

EPA 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)
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.

Expected Results:

This research will provide information to aid managers in restoring native plant communities after the removal of French broom.

Supplemental Keywords:

terrestrial plant ecology, habitat restoration, exotic species., Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Restoration, State, Ecology and Ecosystems, Aquatic Ecosystem Restoration, exotic plant species, prescribed burns, coastal environments, restoration strategies, invasive plant species, ecological recovery, seed banks, California (CA), ecological impact, coastal California grasslands

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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