Coastal Sage Scrub Restoration on a Budget

Researcher:

Theresa S. Talley
Adjunct Faculty
University of San Diego &
UC San Diego
E.: tstalley@ucsd.edu
T.: (530) 220-0818

Relevant Links:

Tools:

Revised:

October 12, 2010

Theresa S. Talley (in baseball cap) conducts field experiments with Hoover High School interns

Researcher Theresa S. Talley (in baseball cap) conducts field experiments with Hoover High School interns (from left) Joel Urbina, Daisy Mercado and Amina Ture. The Ocean Discovery Institute supports the interns through its Ocean Leaders Initiative Program.
Credit: Ocean Discovery Institute

October 12, 2010

Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

SAN DIEGO – What are some strategies for inexpensively restoring coastal sage scrub habitats in Southern California that have been overrun by exotics such as ice plants, chrysanthemums, smotherweed and tamarisk?

California Sea Grant researcher Theresa Sinicrope Talley is conducting a series of field experiments at NOAA’s Tijuana River National Estuarine Research Reserve in southern San Diego County to help guide managers on some do’s and don’ts following invasive species eradication.

High school interns Joel Urbina (left) and Amina Ture (in black skirt) educate volunteers at the Tijuana River Estuary. Credit: Ocean Discovery Institute

Based on her first year of results, she recommends the following to stretch restoration dollars:

Mulch with the debris from the pulled-up weeds. Her experiments show that a thick layer of dead plant material will shade out seeds (even those from the weeds) and prevent re-invasions from the virtually endless supply of non-native seeds from landscaped yards. For larger plants such as tamarisk, wood chippers can be used to shred debris. For smaller plants, the dead material can be placed on the ground in thick layers.

Plant native species after a major weed pull. “If you don’t get native plants in the ground, the weeds will just come back after the first rain,” says Talley, who is adjunct faculty at both the University of San Diego and UC San Diego.

High school interns Daisy Mercado (left) and Joel Urbina measure newly planted native plants at a restoration site at the Tijuana River Estuary. Credit: T.S. Talley/USD

Include some fast growing, larger native species in the replanting. In the early stages of habitat recovery, establishing a base of primary productivity is critical, she says. The return of native biomass is associated with lower rates of re-invasion, faster recovery of soil communities, and greater numbers of insects and spiders, upon which many bird species feed. For high marsh habitats (which transition to sage scrub), some large native plants to consider are alkali heath and coastal goldenbush. In coastal sage scrub, California sagebrush and four-wing saltbush were observed to quickly add biomass.

Include a diversity of native species in the replanting. The preliminary data show that plots with greater plant diversity have more abundant and diverse insect and spider communities, and faster decomposition rates. Talley thinks it likely that the positive effects of plant diversity will increase as the restoration sites mature.