Photo Courtesy of the U.S. National Park Service
The Santa Monica Mountains are at higher fire risks than ever before due to increasing nitrogen levels, according to initial three-year study results conducted by the National Park Service.
A recent press release from the National Park Service said researchers tested ten sites within the Santa Monica Mountains for nitrogen deposition levels to understand why California’s native coastal scrub sage is an endangered habitat. The lowest nitrogen levels have been found near the ocean where the air is cleaner, while higher levels are found closer to the city. Researchers have also been adding varying levels of nitrogen to test the response of native plants in proximity to the best air quality.
University of California Riverside’s plant ecology professor and natural resources specialist Edith Allen, UCR’s professor of natural and agricultural sciences Andrzej Bytnerowicz, and U.S. Forest Service plant pathologist Mark Fenn are leading the the study, which began in 2012.
Allen described the problem in a metaphor: “For people who have ever had a garden, if you have weeds, you fertilize your garden with nitrogen … So you always hope when you fertilize your garden that your crops will grow or your flowers will grow. What you get when you fertilize is a lot of weeds.”
Invasive species like the grasses from the Mediterranean in the Santa Monica Mountains thrive on nitrogen.
“The weeds dominate and the invasive species dominate, because they have a higher demand for nitrogen,” Allen said.
The two most common forms of nitrogen pollution emissions are from automobile engines and agriculture fertilizers, Allen said.
These invasive species are not only taking over the natural landscape, but “they don’t become very productive … until nitrogen fertilization,” Allen said. Nitrogen acts as food for these invasive species, causing them to become more productive and more prone to fire.
Native coastal sage scrub plants burn annually in intervals of every 20 to 40 years, whereas the invasive Mediterranean grasses have an average burn rate around every five years.
The current crisis in the Santa Monica region is increasing fire risk as well as possible losses of biodiversity.
“Ultimately, what we need to be able to do is clean the air to reduce the amount of nitrogen deposition,” Allen said.
Freshman Micah Lambert grew up at Pepperdine, witnessing the 2007 fire that destroyed Malibu Presbyterian and came right up into her backyard. “The ash was in the air and you couldn’t go outside,” she said. “I remember my neighbor was fighting [the fire] with a hose until the firefighters came.”
She said about the study, “California is so beautiful and such a unique environment. It’s so important to preserve it and make it a place everyone wants to live in.”
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Follow Gretchen Andsager on Twitter: @gmandsag41
