areas of blue oak woodland and open grassland are covered with well-established
individuals of three species of needlegrass, Nassella pulchra,
N. cernua, and N. lepida. Cool, damp, north-facing
slopes under interior live and black oaks support luxuriant stands
of fescue (Festuca californica and F. idahoensis).
California melic and blue wildrye (Elymus glaucus) thrive
in slightly mesic areas with overstory trees. Many native forbs
also thrive in the grasslands of the Reserve, often offering spectacular
spring displays of lupines (Lupinus nanus).
As in nearly all of California, much of the grassland
is either dominated by or has a significant proportion of exotic
annual grasses. Bromes (Bromus diandrus, B. hordeaceus,
and B. madritensis) and wild oats (Avena fatua)
comprise the majority of the exotic grass biomass, but there has
been recent encroachment by aggressive and
problematic grasses such as medusahead (Taeniatherum caput-medusae)
and barbed goatgrass (Aegilops triuncialis). In addition
to the native forbs, the grasslands also include many non-native
dicots such as filaree (Erodium cicutarium), burclover
(Medicago polymorpha), and yellow starthistle (Centaurea
The majority of the areas of grasslands that appear
on the vegetation map occur on south- and west-facing slopes. Some
are adjacent to chaparral, and some appear within woodland areas
where the tree cover decreases. The California Annual Grasslands
Alliance covers only 1.0% of the Reserve. Only one small area on
the Reserve, which was bulldozed during the 1992 fire, appears as
the weedier “Upland Annual Grasses” community on the
vegetation map. This community covers less than 0.01% of the Reserve.
Over the past 10 years, the Reserve staff has actively
controlled goat grass, medusahead, and yellow starthistle with herbicides.
Many, but by no means all, of the recent invasions by these species
have occurred along roadsides, making populations both visible and
treatable. Populations in the steep, remote portions of the Reserve
will be much harder to control, but offer some evidence of whether
control measures are necessary.
There is a small area of Wet Meadow Grasses Superalliance
on Bureau of Reclamation land east of the Reserve. This is probably
associated with an artificial pond adjacent to a creek bottom.