East Fork restoration site in Bommer Canyon Nature Preserve
The City of Irvine’s (COI) East Fork area in the Bommer Canyon Nature Preserve has been part of a large-scale restoration project with Irvine Ranch Conservancy since 2018. This 4.2-acre portion of Bommer Canyon, located where the East Fork trail meets the Bommer Pass trail, was historically used for agriculture, and severely degraded with invasive plant species such as mustard and non-native grasses. The site is typically only accessible during Wilderness Access Days and guided activities.
IRC’s Restoration and Enhancement Team took on this endeavor to restore habitat for threatened species such as the California gnatcatcher and cactus wren. This required removing invasive plants and replacing them with a diverse set of native shrubs. IRC’s team experimented with several restoration techniques in the process and involved community volunteers frequently.
IRC’s Restoration and Enhancement Team took on this endeavor to restore habitat for threatened species such as the California gnatcatcher and cactus wren. This required removing invasive plants and replacing them with a diverse set of native shrubs. IRC’s team experimented with several restoration techniques in the process and involved community volunteers frequently.
One approach was to install container plants into the weeds with the expectation that the installed plants would gradually shade out surrounding weeds as they mature. In 2018, the first year of this project, California experienced a severe drought which meant the container plants had to be hand watered to keep them alive. Another obstacle was that rabbits and gophers destroyed the shoots and root systems and killed 90% of the container plants. The project team learned their lesson and replanted the site the following year using several hundred wire mesh baskets to protect the roots and above ground cages to protect the shoots and saw successful establishment.
Solarization was another experimental approach used at East Fork. This involves using the sun’s energy to superheat wet soil and kill most weed seeds. This labor intensive but highly effective technique allowed the team to sow the solarization beds with seeds of diverse shrub and wildflower species. Lessons learned from this site have helped the team use solarization at other small scale restoration projects.
The third experimental technique was “facilitated restoration,” in which the team supports the growth and expansion of existing patches of native vegetation by carefully timed and strategically placed actions. Though this is a slower process, it has proven to be successful in the East Fork area and can be combined with the other methods of restoration.
Together, these approaches have helped improve the habitat quality for native wildlife within the East Fork area. This portion of the larger Bommer Canyon Preserve restoration project is nearing completion and little maintenance will be needed in the future. The Restoration and Enhancement Team is now tackling new restoration challenges elsewhere in the Bommer Canyon Preserve.
The East Fork trails will be accessible to the public during this weekend’s Bommer Canyon Wilderness Access Day, and on future guided activities. To learn more about this ongoing project, visit IRConservancy.org, LetsGoOutside.org or follow the Landmarks on Facebook, Instagram and Twitter.
Solarization was another experimental approach used at East Fork. This involves using the sun’s energy to superheat wet soil and kill most weed seeds. This labor intensive but highly effective technique allowed the team to sow the solarization beds with seeds of diverse shrub and wildflower species. Lessons learned from this site have helped the team use solarization at other small scale restoration projects.
The third experimental technique was “facilitated restoration,” in which the team supports the growth and expansion of existing patches of native vegetation by carefully timed and strategically placed actions. Though this is a slower process, it has proven to be successful in the East Fork area and can be combined with the other methods of restoration.
Together, these approaches have helped improve the habitat quality for native wildlife within the East Fork area. This portion of the larger Bommer Canyon Preserve restoration project is nearing completion and little maintenance will be needed in the future. The Restoration and Enhancement Team is now tackling new restoration challenges elsewhere in the Bommer Canyon Preserve.
The East Fork trails will be accessible to the public during this weekend’s Bommer Canyon Wilderness Access Day, and on future guided activities. To learn more about this ongoing project, visit IRConservancy.org, LetsGoOutside.org or follow the Landmarks on Facebook, Instagram and Twitter.
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