The feasibility of chaparral restoration on type-converted slopes

Abstract

Increased fire frequency, livestock grazing, and other disturbances have converted many chaparral stands in southern California to non-native annual grassland. Competition from annual grasses interferes with the establishment of chaparral shrubs, presenting a challenge to restoring chaparral in type-converted areas. In this study we examined the feasibility of restoring chaparral by exploring several methods of restoration on type-converted slopes in San Timoteo Canyon, Riverside County, California. We assessed the effectiveness of a broad-spectrum herbicide (glyphosate) and a grass-specific herbicide (fluazifop-p-butyl) in facilitating shrub establishment. In addition, we compared the success of seeding and planting containerized shrub seedlings as methods of restoration and examined the soil seed bank to see if there was a relict seed bank that could be manipulated to promote restoration. The broad-spectrum herbicide application significantly increased soil moisture and the successful establishment of transplanted seedlings. The grass-specific herbicide, applied later in the season, was less effective. Seeding was unsuccessful, most likely due to low rainfall during the study, and few germinable seeds of native chaparral species were detected in the grassland soil.

Parent Publication

• Proceedings of the chaparral restoration workshop, California

Citation

Engel, Megan D.; Williams, Kimberlyn; McDonald, Christopher J.; Beyers, Jan L. 2019. The feasibility of chaparral restoration on type-converted slopes. In: Narog, Marcia, tech. coord. Proceedings of the chaparral restoration workshop, California. Gen. Tech. Rep. PSW-GTR-265. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 37-49.