California's grasslands were once vegetated by native
perennial grasses. But during the last 200 years, exotic annual grasses
from Europe started taking over, and now only 2 percent of the state's
grasslands are vegetated by native perennial grasses.
ARS is working with
university researchers and environmental groups to study how revegetation
affects soil and water quality, invasive weeds, and availability of
grazing forage. Plant physiologist Stephen M. Griffith, of the Forage
Seed and Cereal Research Unit in Corvallis, Oregon, is leading ARS's
efforts in this research.
Studying three grass fields 30 miles west of Sacramento,
California, Griffith hopes to develop a better understanding of how
well revegetation efforts work. One field contains annual grasses, one
is a newly restored field of native grasses, and the third has contained
native grasses for 10 years. "There are many advantages of the
native grasses, whether as forage for animals or as habitat for wildlife,"
Unlike annual grasses, perennial grasses turn green faster,
stay green longer, and produce more biomass. This equates to more protein
and higher value forage for both wildlife and livestock. The site that
contained annual grass had significantly fewer tons per acre of aboveground
plant biomass accumulation than the two plots that were restored to
Native grasses integrate better with other plants. That
diversity of plants attracts wildlife not found in annual grasses. "We've
noticed a significant change in biodiversity in the 4 years that ARS
has used my farm for research," says California farmer John Anderson.
Furthermore, native grasses improve soil and limit erosion.
There are about 300 species of native grasses, which began
to get displaced when Spaniards settled in California in the mid 1500s,
bringing livestock and new land practices. Annual grasses took over
in the 1800s, possibly because of overgrazing.
ARS is working with Audubon California on restoration
projects on farms and ranches. It is difficult to get perennials established
because annuals outcompete them. "We're looking at various methods,
such as using controlled fires, applying herbicides, and determining
what species grow best in which areas of California," Griffith
He does say that once perennials are established, their
deep roots should help them get rid of annual grasses. And ranchers
now know the importance of not overgrazing, so there likely won't be
a repeat of what happened in the 1800s.
One problem is that native-grass seed is very expensive.
It may cost $40 a pound, while turfgrass seed is about 50 cents a pound.
Griffith hopes that showing the positive effects of native grasslands
will influence supply and demand and make native grass more affordable.
Collaborators elsewhere are studying whether native grasses
have value as forage; which plantsbesides grassesmake up
a healthy grassland; what kinds of wildlife appear after native grasses
are reintroduced; and whether GIS analysis can determine biomass of
grasslands.By David Elstein, Agricultural
Research Service Information Staff.
This research is part of Rangeland, Pasture, and Forages,
an ARS National Program (#205) described on the World Wide Web at www.nps.ars.usda.gov.
Griffith is in the USDA-ARS Forage
Seed and Cereal Research Unit, 3450 S.W. Campus Way, Corvallis,
OR 97331; phone (541) 738-4154, fax (541) 738-4160.
"Restoring California's Native Grasses" was published
in the May
2004 issue of Agricultural Research magazine.