Although it is disappearing, the official state grass of California has the ability to live 100 years or more. New research shows that sheep and cattle can help you achieve that longevity.
Purple grass once dominated the state’s grasslands, serving as food for Native Americans and more than 330 land creatures. Today, California has lost most of its grasslands, and needlegrass occupies only one-tenth of what remains.
It is drought tolerant, promotes the health of native wildflowers by attracting beneficial root fungi, burns more slowly than non-native grasses, and accelerates post-fire recovery of burned lands. For these and other reasons, many of those working to restore the habitat hope to preserve the needle.
“Wherever it grows, these tall, thin clusters become focal points that are beautiful and beneficial to the environment,” said UC Riverside plant ecologist Loralee Larios. “However, identifying successful management strategies for a species that can live for a couple of hundred years is challenging.”
To address this challenge, Larios teamed up with University of Oregon plant ecologist Lauren Hallett and Northern California’s East Bay Regional Park District. They tracked the health of nearly 5,000 individual needle clusters over six years, including a year of El Niño rainfall and a historic drought.
The researchers took measures of plant health, including growth and seed production. They placed small bags over many of the grass clumps to capture the seeds and quantify the number of seeds they produced.
Their findings, now published in the Journal of Applied Ecology, were that purple needlegrass performed best in places where sheep were allowed to graze. The positive effects of grazing were amplified in periods of wetter weather.
Previously, the park district spent a decade trying to gauge the success of its pasture maintenance techniques. However, the district’s method of applying a strategy such as grazing and then measuring the percentage of needlegrass clumps in a given area resulted in data that did not follow a discernible pattern from year to year. The other.
“By tracking each plant over time, rather than broadly scanning an area, we gained much more clarity on how the grass responds to grazing,” explained Larios. “Perhaps counterintuitively, we found that needlegrass generally died when sheep couldn’t graze on it.”
When sheep were removed from the study sites, needlegrass at all but two sites became less healthy. The researchers would like to know if the two sites that remained healthy have needle grasses that are genetically different.
Grazing is a controversial strategy for grassland restoration. Some conservationists believe that sheep eating the target grass, especially during already stressful drought years, does not improve their survival. As early as the 1800s, some researchers hypothesized that the combination of grazing and drought led to the loss of perennial grasses.
Although the drought was not beneficial to any of the plants in this study, the researchers believe that grazing helped needlegrass survive in at least two ways. One, by trampling leaves and other organic debris, the sheep created space for new needle grasses to grow.
“Sometimes you get pencil-deep litter — lots of dead, non-native grass piled up. It’s hard for a little seed to get enough light through all that,” Larios said.
Second, sheep eat non-native grasses that generate growth-suppressing debris and compete with purple needlegrass for resources.
When the Spanish colonized California, they brought forage grasses like wild oats that they thought would benefit livestock. Introduced grasses are spreading and now dominate the state’s grasslands.
“Our grasslands are known as one of the largest biological invasions in the world,” Larios said.
California has up to 25 million acres of grasslands, equivalent to the combined areas of Massachusetts, Connecticut and Rhode Island. While Larios doesn’t think it’s possible to rid the state of all non-native grasses, he said it’s possible to maintain or even increase the amount of purple needle grasses.
“It’s great for carbon storage, which mitigates climate change, doesn’t serve as fuel for wildfires, and cultivates space for wildflowers that pollinators can use,” Larios said. “We want to keep all those benefits.”
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