Invasive species have the potential to disrupt healthy ecosystem function by competing for resources with native species, reducing biodiversity, altering the habitat itself, and even causing the extinction of native species. In 1991, Bridal Broom (Genista monosperma), a shrub in the legume family, was identified as an invasive species in northern San Diego County. This species can outcompete native plants and form monocultures in Mediterranean climates, which could degrade essential habitat for several threatened and endangered species in the area and present challenges for wildfire control programs. Because of this, in 1996 the shrubs were cut down and herbicide was applied to their trunks. Despite annual treatment, the population has not been eradicated due to the species’ prolific seed production and persistent seed bank that resists drought, fire, and remains viable up to 26 years in the soil. Therefore, understanding seed emergence will help managers control new seedlings and prevent G. monosperma from spreading further. Previously, we documented the spatial extent of the seedbank around dead plants. Currently, we are investigating if seed depth affects seed emergence. Seeds collected from the invasion site are planted at different depths to determine emergence limits. These results will inform a potential solarization treatment that would trigger germination and facilitate eradication of the existing seedbank from the area.
