By Ripping Out Its Lawns, Is L.A. Choking Out Its Worms, Butterflies and Birds?
In her busy bird-supplies shop in Sherman Oaks, Bonnie McFarlin describes her motionless butterfly habitat with dread. "In a good year we would have, I don't know, 25 or 50 monarchs in there at a time, and this year we had none."
McFarlin, who co-owns Wild Wings Backyard, worries about the effects of the drought, which is obliterating the tiny areas of cool L.A. dampness and the mud that butterflies and insects seek out, in a chain of life that is crucial to California's bird population. And she reserves a special kind of anger for the actions of Gov. Jerry Brown and Sacramento.
Two of Brown's rules aimed at water conservation, one banning municipalities from watering their grassy medians in roadways and another encouraging people to strip out their grassy lawns, are believed to have taken a toll that was not discussed in hearings or mentioned by Brown in speeches he gave to persuade urban dwellers to join his war to cut water use.
"The governor ordered cities not to water their grassy medians, but those medians have mature trees growing in them," McFarlin says. "When trees aren't watered, they don't have the sap to defend themselves from pests that eat them from the inside out. You don't know they are dying until they fall over."
McFarlin is no fan of grassy lawns, preferring low-water gardens, but she says, "A lot of people in our area did not put in any native-plant replacements in reaction to the California turf-removal rebate. They just left the ground barren. But birds need worms, insects, seeds and nectar."
She believes she has a measuring stick for the damage thus far: She says her shop is selling far too much birdseed, even for a drought. Her suspicion is that L.A.'s flora is no longer producing enough seeds for its longtime bird population. "I can't even imagine next year or the year after. This is going to multiply on itself," she says.
In July, two UC Riverside Agricultural Extension teachers set off a modest stir in academia, publishing on their website a position paper decrying California's decision to eradicate urban lawns as a means to help satisfy state water cuts. Meanwhile, the state lags on other water-conservation approaches such as the move to greywater — simple hose networks that transfer sudsy but safe dishwater and washing machine water to yard irrigation, which replenishes the soil and local watershed while keeping trees and landscapes healthy.
"Nobody thought this out," says UC Riverside's Donald R. Hodel, a horticulture expert and authority on palms, whose special emphasis is on management of woody plants and plant water use. "Like everything for the past 30 years when it comes to water in California, they chose by knee-jerk reaction."
Hodel and Dennis Pittenger argued in their paper that California is greatly exaggerating the water saved by turf and landscape removal — and damaging the urban environment in its rush to show it is achieving big cuts.
"That's why we wrote this paper," Pittenger says. "They're throwing out the baby with the bathwater in some respects. The turf-removal program under the Metropolitan Water District has oversold how much water they are claiming they can save — it's almost mathematically impossible."
The MWD says a 1,500-square-foot yard uses 66,000 gallons of water a year, enough to flood it with 5.86 feet of water, which Hodel calls "almost double what L.A. needs and not what they use."
Bill McDonnell, MWD's water-efficiency manager, disagrees, saying that's about right. He says there are no good studies of how much water Southern Californians use on yards in their mostly Mediterranean climate, so MWD mixed data from moist Marin County with data from southern Nevada, a desert.
The real answer will come 12 months from now, McDonnell says, when MWD completes its study of a "statistically valid sample" of homes where owners removed the lawns about four years ago, replacing them with various coverings. "Your UC Riverside guys? We're as interested as they are" in the results, he says.
At UC Davis, Loren Oki of the statewide UC Cooperative Extension, a national program that links university researchers and growers, says he took issue with a few points made by Hodel and Pittenger but was largely in their camp. Among the obvious problems created by California's turf-removal program, Oki says, is "encouraging people to plant during the heat of the summer, which is the worst time" for new plants to survive in the ground. He predicts many of the low-water plants will not survive the late-summer heat.
He also anticipates widespread, needless water waste because this time of year "requires far more watering of new plants" than if the state had allowed people to install their replacement plants in the fall.
But potentially worse than all of these problems — according to Oki, Hodel and UC Davis soil biogeochemist William R. Horwath — is the possibility of killing the "decomposition community" that lives in the soil and of ruining mature trees growing in that soil across California.
Horwath explains that when cities and homeowners remove vegetation from land, that diminishes the diversity of the soil biology, especially the larger fauna such as worms, which feed off of the droppings of leaves and other materials from plants. "If you are not growing anything, just gravel or mulch, you'll be losing a lot of worms, and you will at the same time be losing a lot of carbon from under the soil back into the atmosphere," Horwath says.
Yards, it turns out, are "big carbon sinks" filled with underground activity led by the decomposing community of life unseen. "There's two to three times more carbon in the soil as in the atmosphere," Horwath says. "It requires growing vegetation to maintain the carbon in the soil, and if you remove that, it creates a one-way directional loss."
Moreover, he says, letting green urban areas go brown and allowing the soil to die interrupts important cycles, creating less grass seed and weed seed, which in turn reduces food for birds, worms and all the interconnected life.
"These are all the ancillary services we get from the plants in a yard that nobody thought of," Horwath says. "Of course this all needs to be thought out, but instead it was an on-demand decision. Nobody has thought about the consequences of what removing the vegetation from your yard will do. And in the present environment, no, I don't think it will be discussed. Not in this drought."
Jacky Surber, a customer at Wild Wings Backyard and owner of Urbafloria, a low-water-landscaping firm, has been thinking about how to undo damage to mature trees and soil. Surber, who is also vice president of the Association of Professional Landscape Designers for the Greater L.A. District, says the black weed-suppression fabric currently showing up beneath gravel and mulch in stripped yards all over Los Angeles is in fact a soil killer that's also highly ineffective at killing weeds. She urges people to lay down biodegradable and soil-friendly newspaper or cardboard instead of black fabric, covering that with six inches of wood chip mulch, not gravel.
Then, "You soak the whole thing, and all that organic material starts to decompose. Even if you can't afford plants, it's a huge step in the right direction. No gravel. No black fabric. You create healthy soil under the mulch. You buy a $5 drought-tolerant plant here and there, like the California lilac that eventually will grow 10 feet wide."
McFarlin, the store owner, says that if she were governor, "I'd find a rational way to keep our trees alive, because they're critical to our lives here."
She has an even more modest request of L.A. residents: "Please put out a small dish of water. The dragonflies, butterflies, all of our creatures are in desperate need. Help us save them."
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