Simple Approaches to Improve Restoration of Coastal Sage Scrub Habitat in Southern California

• Published in: Natural areas journal 2016-01, Vol.36 (1), p.20-28
• Main Authors: Bell, Carl E, Allen, Edith B, Weathers, Kristin A, McGiffen, Milton
• Format: Article
• Language: English
• Subjects: coastal sage scrub; cost analysis; cost effectiveness; deblossoming; farming systems; fires; flora; fluazifop; forbs; glyphosate; government agencies; grasses; grazing; habitats; herbicide; humans; indigenous species; inflorescences; land management; livestock; perennials; shrublands; shrubs; sowing; spraying; spring; weed control; weeds
• ISSN: 0885-8608; 2162-4399
• DOI: 10.3375/043.036.0107

Much of the coastal sage scrub habitat in Southern California that existed prior to European settlement has been developed for human uses. Over the past two to three decades, public agencies and land conservation organizations have worked to acquire some of the remaining lands for preservation. Many of these lands are degraded by past intensive livestock grazing, farming, and frequent fires, and the native flora has been replaced by weedy, exotic annual grasses and forbs, mostly of Mediterranean origin. Restoration of native flora is challenging and there are few successful examples to provide guidance on effective methods. Cost is also an important and prohibitive factor. Competition from weeds is one of the most difficult impediments to establishing native vegetation, which often persists in the seedbank. We compared annual applications of the nonselective herbicide glyphosate over multiple years, followed by a final year with the grass-specific fluazifop, as a simple, low cost method of reducing the exotic seedbank sufficiently to allow native vegetation to establish. This approach was combined with seeding native forbs, herbaceous perennials, and shrubs in one half of each treatment plot. Herbicide treatments were made in the spring each year from 2006 to 2010, and were combined with weed trimming in 2010 and 2011 to remove exotic forb inflorescences, and raking to remove litter. In 2010, native plant cover in herbicide-treated plots was about 50%, consisting of 43 species, compared to