Plants fight it out on ranch

Irvine Ranch and UC Irvine researchers are undergoing a project that examines the ranch’s native plant communities and its potentially threatening, non-native plant species.

The research project is the first launched that’s part of a five-year, $1-million grant awarded to UCI in November by the Irvine Co. and its chairman, Donald Bren. The researchers will scientifically investigate the ranch’s environmental challenges and come up with solutions.

Some of the ranch’s non-native plants were brought over from the Mediterranean rim by California’s early Spanish colonialists.Those foreign plants thrived in the Southern California climate, which is similar to sections of the Mediterranean.

But over time, the non-native species have started pushing out the native ones, which are important for sustaining the wildlife whose habitat is the land in and around Irvine Ranch, scientists say.

The agricultural practices that accompanied the cultivation of non-native flora also affected the survival of the native plants. Many of the non-natives thrived in a disturbed environment, continuing to grow even if they were plowed by machines, grazed on by animals or singed by brush fires. The native plants, however, did not grow well under such adverse conditions.

“It’s the initial disturbance — whether it’s overgrazing, frequent fire or a plow — that takes out the adult native community,” said Megan Lulow, the senior field ecologist at the Irvine Ranch Conservancy.

The Irvine Ranch covers 93,000 acres — or one-fifth of the surface area of Orange County — and stretches from Newport Coast to the Cleveland National Forest.

As part of his philanthropy, Bren donated more than half of the ranch land — 50,000 acres — for permanent environmental conservation.

The Newport Beach billionaire also created the conservancy and set aside $50 million for the long-term management, preservation and restoration of the land’s natural resources, according to a biography of Bren posted on the Irvine Co.’s website.

The new research project is focusing mostly on coastal sage scrub in the ranch’s Loma Ridge area. Lulow said many locals would recognize the plant.

“When you’re walking or hiking, it’s all the scrub that you see,” she said.

Native wildlife — such as the coastal cactus wren, the California gnatcatcher, bobcats, foxes, coyotes and mountain lions — depend on the scrub. But as the native community becomes more threatened, she said, the opportunity for growth and to produce more seedlings becomes difficult.

“The native community is having a hard time colonizing these patches because the non-native has taken hold,” she said.

That’s where UCI comes in.

Diane Pataki, director of the Center for Environmental Biology at UCI, and her team are studying how to save the coastal sage scrub and other native species by using restorative ecological techniques.

“Oftentimes restorations aren’t successful because if you … plant seeds, there is still going to be competition,” Lulow said.

Lulow said that weed control and microbial research will come into play while finding the best way to re-establish the indigenous plant communities.

“We’re testing different microbes in the soil,” Pataki said. “It’s really difficult to do. The non-natives come right back. That’s part of the research … what makes the (non-native) seeds so invasive?”

Pataki is looking forward to doing valuable research in her campus’ backyard.

“People have wanted to work there for a long time,” she said. “Coastal sage scrub used to be really prevalent. There is certainly the possibility for certain species to go extinct.”