The coastal cactus wren builds its nests in patches of old-growth prickly pear cactus, providing itself protection from predators.
However, recent fires and past land uses have eliminated most of the mature cactus, which in turn threatens local cactus wren populations.
Irvine Ranch Conservancy Docent Lynda Armbruster plants a cactus bulb during a restoration project.
JEFFREY ANTENORE, FOR THE ORANGE COUNTY REGISTER
Organizations such as the non-profit Nature Reserve of Orange County, the city of Irvine and the Irvine Ranch Conservancy are working together to expand the wren's habitat, by connecting isolated patches of prickly pear cactus with each other to over time create a larger, contiguous habitat for the coastal cactus wren.
But why go to all this effort? It's just one bird, and one plant.
"If you think of a strong, bio-diverse ecosystem as a building and individual species as bricks, each brick you remove makes the building weaker," said Michael O'Connell, executive director of Irvine Ranch Conservancy. "If enough bricks disappear, the building crumbles. This is what happens in ecosystems too."
The conservancy works with landowners such as OC Parks and the city of Irvine and other partners to help them manage their lands and obligations under the Natural Community Conservation Plan.
One such project underway in the Shady Canyon area of Irvine is the Mule Deer Restoration Project, named for its proximity to the Mule Deer trail in the city of Irvine's Open Space Preserve.
The conservancy is restoring more than two acres of habitat, including a number of cactus plantings.
The area was grazed by cattle until the end of the last century, leaving non-native grasses and other weeds that inhibit re-growth of native plants.
The coastal cactus wren is not a strong flier, so young birds looking for their own place to live don't really fly too far from the nest. Patches of cactus have to be relatively close to each other for wrens to move among them.
This restoration project is part of an overall plan for "habitat linkages," which will eventually connect patches of existing coastal cactus wren habitat in the James Dilley Reserve off Laguna Canyon Road to these in Shady Canyon.
In addition to native grasses and shrubs, planting plans include 4,500 prickly pear cactus "pads" (oval flat segments of the cactus sometimes called "nopales"), along with 20 large, mature cactus plants to anchor the cactus islands.
By incorporating mature plants, the conservancy hopes to encourage a faster return of coastal cactus wrens and nesting.
The project includes before-and-after monitoring of both the cactus patches and coastal cactus wren to track growth and population expansion.
Along with conservancy staff, the UC Irvine Center for Environmental Biology is also partnering in the project. A UCI scientist tests soil before planting and during the project to track changes, and environmental science students are participating in planting and data collection.
The public is also welcome to join in the Mule Deer Restoration project and help build the habitat linkage. To learn more about these activities or to register, visit irlandmarks.org/activities.
- This story was submitted by Jenn Starnes of the Irvine Ranch Conservancy