California’s state grass Stipa Pulchra, more commonly known as purple needlegrass, has been slowly disappearing. Purple needlegrass can live for 100 years or more and used to cover numerous parts of California, but has now been destroyed by non-native grasses. Purple needlegrass is drought resistant and promotes the health of native wildflowers by attracting helpful fungi. For this reason, it has become the target of various different restoration outplantings. Now, it appears UCR ecologist Loralee Larios may have identified a successful long-term management strategy to help preserve the purple needlegrass.
Larios recently published a research article detailing how she and University of Oregon plant ecologist Lauren Hallett went to the East Bay Regional Park District in Northern California. They tracked nearly 5,000 individual needlegrass clumps over the course of six years, including a historic drought and an El Niño rain year. The researchers paired the clumps into grazed plots with sheep and cattle and ungrazed plots with no grazing animals.
What they found was that the grazed needlegrass populations maintained a positive average population growth rate while ungrazed populations declined. Larios and Hallett also observed that grazing had a larger positive effect during wet years compared to drought. This was because grazed needlegrass populations tended to have a larger proportion of mature growth at the end of the drought compared to ungrazed populations.
The use of grazing for preservation, however, is controversial. The survival of needlegrass during the drought years seem precarious as sheep and cattle rely on it for sustenance, according to some grassland conservationists. But the researchers believe that grazing helped the needlegrass by tramping on debris which gave space for new needlegrass to grow. This helped bolster the researcher’s belief that conservation efforts should focus more on the promotion of adult growth of the needlegrass for overall population success. The sheep and cattle also ate the non-native grasses that threatened to edge out the purple needlegrass, another benefit.
While purple needlegrass has a multitude of benefits, it doesn’t mean that the conservation efforts are easy. Several park districts just like the one used for this study have been researching ways to preserve the needlegrass. But the solution the researchers have put forth is one that does not contain any massive logistical hurdles to implement and is cost effective compared to many alternatives out there. Whether or not California’s grassland conservationists can embrace it remains to be seen.
