The Sepulveda Basin Wildlife Reserve suffers from most of the ills that may be anticipated of a pure space positioned in the course of the nation’s second-largest metropolis, together with litter and even biohazards comparable to discarded needles from close by drug use.

However on Saturday morning just a few hundred volunteers had one other perpetrator of their sights: Rhamphospermum nigrum, a nonnative plant higher generally known as black mustard that has flourished within the 225-acre reserve and the broader Sepulveda Basin Recreation Space.

The plant, with its four-petaled yellow flowers in bloom, fills the basin’s meadows and paints a bucolic image that belies what it truly is — an invasive weed that crowds out native crops comparable to sage and poppy which can be essential to the well being of the basin, its pure wildlife and the Los Angeles River that runs by it.

“It does look harmless, but it becomes a mono crop, and this is the main enemy to biodiversity,” mentioned Dan Mott, environmental educator with Mates of the Los Angeles River, which held the occasion with the California Native Plant Society and San Fernando Valley Audubon Society. “The native species can’t be here, and all the birds and the insects that are supposed to be in this area, they don’t want the mustard.”

The grasslands additionally seize much less carbon and aren’t as efficient as native species in filtering runoff that enters the river, he mentioned. The plant is native to North Africa, temperate areas of Europe and elements of Asia, and it’s believed to have been launched tons of of years in the past.

Adrian Sharp and his son Milo, 6, head all the way down to take away invasive mustard weed on the Mates of the Los Angeles River’s Habitat Restoration and Earth Month Celebration on the Sepulveda Basin Wildlife Protect on Could 24, 2025. .

The environmental group has been conducting habitat restoration within the reserve since 2019, with this weekend’s occasion additionally a late celebration of Earth Day, after a previous occasion was rained out. On Saturday morning, the volunteers spent hours pulling up the black mustard, specializing in a patch of land with 5 giant coast dwell oaks. The tree is native to California and resistant to fireplace, however not if surrounded by thick mustard weed undergrowth.

“If there’s a bunch of invasive species creating fuel underneath it, it’s just kind of burning like a bonfire. It overwhelms the tree’s ability to protect itself,” mentioned Mott, who figures that in 5 years essential areas of the reserve ought to be largely cleared of the weed.

Wes Vahradian, 18, who has been volunteering with Mates of the Los Angeles River for 4 years, was serving as a volunteer chief and monitoring how a lot habitat was being restored utilizing ArcGIS, a web-based mapping software program on his telephone.

Brent Kado goes over the invasive mustard weed that volunteers take away on the Sepulveda Basin Wildlife Protect.

By 10:30 a.m., the app indicated that a few quarter of an acre had been restored. “We’ve done pretty solid here, and it’s just a great way for us to kind of measure the impact we’re making. We’ve done it all over the Sepulveda Basin,” he mentioned.

Vahradian is getting into his senior 12 months at Campbell Corridor, a non-public college in Studio Metropolis that requires college students to interact in group service. Vahradian mentioned he was interested in the environmental group as a result of he has lengthy been fly-fishing within the river — “which is kind of crazy, but you can totally fish in it.”

He mentioned that though the mustard weed does regrow, progress has been made over time. “The whole premise is that the Sepulveda Basin is supposed to be a natural ecosystem, a place for birds when they’re migrating to come and take a break.”

The black mustard that was pulled up was collected into 30-gallon paper backyard luggage that can be hauled away and buried in a landfill. Mott mentioned the purpose is to finally compost the weed.

Eamon Wilson passes invasive mustard weed to a different volunteer for disposal on the Sepulveda Basin Wildlife Protect.

Zia Shaked, 11, who mentioned her favourite exercise was studying, had spent the morning along with her mom stuffing 5 luggage filled with the weeds that had been uprooted by her youthful brother and cousin.

“I learned that folding the weeds was really helpful before you put them in, because otherwise you get a mouthful of weeds in your face,” she mentioned. “I was just putting the weeds in the bag. I didn’t even notice how much space that was cleared up and I looked up, like maybe a half an hour later.”

Shanna Shaked, the lady’s mom, mentioned this was the second time the Santa Monica household had been out restoring habitat, although it was the primary time for her daughter.

“It felt like a really good way to spend the morning, to be outside and doing something that felt helpful for nature,” mentioned Shaked, an adjunct professor at UCLA’s Institute of the Setting and Sustainability. “It was a team effort.”

Mott mentioned that the habitat restoration occasions sometimes draw about 150 to 200 contributors however he has undoubtedly seen an uptick in attendance for the reason that Jan. 7 fires that devastated Pacific Palisades, Altadena and different communities.

“I think there was this powerless feeling when the wildfires were happening. You know, we can’t go out there and fight fires ourselves, but this work is actually preventing the spread of wildfires. It’s just something physical, tangible you can do to help the community and help with that problem,” he mentioned.