Grasslands are areas in which the dominant plants are various species of native and introduced grasses and forbs (dicot herbs).  Often there are numerous species of herbaceous plants and sometimes scattered shrubs present.  The grasses that dominate a grassland area may be annuals, perennials or a mixture of the two depending on location.
 
 

In Poly Canyon, grasslands occur in the flat areas and rolling hills that border Briziolari Creek.  Grasslands are typically found on fine textured, clay rich soils of valleys and alluvial deposits at the base of hillsides.  They integrate with coastal live oak woodlands on mesic hillside slopes, with coastal scrub and chaparral on xeric, steep, rocky slopes, and with riparian and freshwater marsh communities in aquatic and semi-aquatic areas along the creek.  Many of the grassland species occur as understory species in the other communities.

The Poly Canyon area has an impressive number of native grasses in the grassland areas, much more than most grasslands in the local areas.  The stands of perennial, native bunch grasses, which dominated the grassland prior to Spanish settlement, have gradually been reduced or eliminated in much of California's grasslands.  Native grassland species have declined because of their lack of adaptations to heavy grazing.  Prior to introduction of cattle by the Spanish, coastal California had no large grazing mammals.  Cattle grazing results in lose of renewal buds in perennial grasses and also greatly reduces the food reserves necessary to get them through dormant phases.  The annual grasses introduced from the Old World are more tolerant of grazing, reproduce quickly, and do not have to store up food reserves.  In addition, many of these introduced annuals are aggressive competitors and over the years have outcompeted and replaced the native perennial grasses.  Native forbs have suffered a similar fate. However, we are fortunate to have some outstanding examples of California native grasslands on some of the hillsides around Poly Canyon beacuse of better management of grazing on campus.

Historically, the changes in the composition of the grasslands in California, including those on the hillsides around Cal Poly, are mostly a function of the introduction and invasion of alien plant species,  the introduction of grazing livestock, and the concommitant changes in grazing intensity and patterns.  Cultivation and fire has also played a role in some areas.  As a result of these changes, the grasslands in most of California is dominated by introduced annuals.  Many of the hillsides around Poly Canyon are presently are dominated by introduced annuals but some native grasses are usually present.

Originally grassland communities covered about thirteen percent of California.  Grasslands occur from near sea level on coastal terraces to about 1200 m (4000 ft) in dry mountain regions of southern and central California.  These communities occur where it is too hot and dry to support woodland vegetation.  A combination of low and often irregular precipitation and high summer temperatures accompanied with long summer drought create conditions unsuitable for most woody plants.

Extensive grassland areas once covered the large interior valleys of California such as the San Joaquin, Sacramento, and Salinas Valleys as well as many smaller valleys.  Most of these large grassland areas, which were found on deep, alluvial soils, have been coverted to agricultural uses or have been urbanized.  Therefore, only a small percentage of California's  historical grasslands still occur and almost all of those are dominated by the introduced annuals discussed previously.

While grasslands may not appear to be diverse to the casual observer, hundreds of plant species grow in California's grassland communities.  The large species diversity found in grasslands is more evident in the spring when many grassland areas display beautiful wildflower fields.  Species composition of grasslands in California may vary signficantly from place to place.  California grasslands vary from north to south and from west to east in California as does the climate.  Even within the same region, significant variation may occur from place to place.  On the Cal Poly campus and on the hillsides around Poly Canyon significant variation in species composition if found from place to place.

For further information on these communities please see  California Vegetation written by V.L. Holland and David J. Keil
 

Common grasses found in Poly Canyon's Grassland Communities:
Avena barbata (slender wild oats)
Bromus diandrus (rip-gut brome)
Bromus hordeaceus (soft chess brome)
Hordium murinum (foxtail barley)
Lolium multiflorum (ryegrass)
Nassella pulchra (purple needle grass)
Vulpia myuros (rattail fescue)

Common forbs found in Poly Canyon's Grassland Communities:
Amsinckia spp. (fiddleneck)
Astragalus curtipes (locoweed)
Cryptantha clevelandii (cryptantha)
Erodium botrys (stokbill filaree)
Plantago sp (plantain)
Sisyrinchium bellum (blue-eyed grass)