Biologists Concerned Woolsey Fire Could Open Door To Non-Native Plant Invasion In Santa Monica Mtns

Dec 6, 2018

Like tens of thousands of acres of land around us that have been blackened, and stripped bare by the Woolsey brush fire, Trancas Canyon looks like the moon. In a few months, these slopes will start to turn green again, but, the question is will it be green in a healthy way?

Mark Mendelsohn is a Vegetation, and Wildlife Biologist with the National Park Service. He says with rain from three storms since the fire, we are already seeing some early signs of recovery, some tiny sprouts here and there.

It’s a race of sorts, pitting native species versus the invasive ones. Mendelsohn says rainfall is the key. He says it’s not just getting rain, but how we get it. He says drought conditions help invasive species, while the series of smaller storms is better for the native plants.

During a hike in the canyon, we find both some sprouting native plants, as well as some invasive species like arundo, which looks sort of like bamboo. Mendelsohn says with 96,000 acres of land burned, and more than 20,000 acres belonging to the National Park Service, there is only so much they can do.

But, he says they are trying to get funding to do what they can. He says there is also something good coming out of the fire as far as nature is concerned. The biologist says we’ll see some native plants we rarely find, because the seeds are activated by fire.

Mendelsohn says while we’ll see green slopes returning next spring, full recovery can take decades.

The biologist says one of the difficult issues is that historically before humans moved to the region, fires of this type in the Santa Monica Mountains were a 50 to 100 year occurrence.  Now, they happen much more frequently. The mountains aren’t getting the chance to fully recover, so in some areas we are seeing a gradual change in the landscape.