Poly Canyon lies in the northeastern portion of Cal Poly's campus in San Luis Obispo, California. Brizziolari Creek flows down Poly Canyon, through the main campus, and joins Stenner Creek near at Stenner Glenn near the edge of campus.   Brizziolari Creek is in the Cuesta Ridge watershed flows from its headwaters down the steep Cuesta Ridge slopes through Poly Canyon.  While the mouth of the Poly Canyon near the main campus has somewhat gentle terrain, just upstream the slopes on either side of Brizziolari Creek form a more narrow, steep canyon.  From the Botanical Garden (about 1 mile up the canyon) eastward Poly Canyon opens up and is surrounded by a complex terrain of rolling to steep hillsides.   This portion of the canyon offers spectacular views of the rolling hills and narrow drainages that comprise the upper watershed of Brizziolari Creek.  These hillsides are covered by a mosaic of various plant communities often with fairly sharp ecotones (boundaries).

The mosaic of plant communities and wildlife habitats of the Poly Canyon have developed in response to the interaction of a complex of environmental features that are variable over the area.  Local climate (wind, temperature, rainfall, fog, etc.), topography, soils, parent materials, biotic components, fire, location of waterways, and natural historical events are all variables and have all historically affected the vegetation on the site.  Past and present land-use and other human caused events have also resulted in changes in the vegetation.  Poly Canyon is home to a great diversity of plants, animals,  plant communities, and wildlife habitats.  Many of these plant and animal species and their habitats are sensitive and must be protected.  Several of these species are listed as rare, threatened, or endangered species.

Soils and geology on the site, like the vegetation, are complex and form a mosaic pattern that often corresponds with vegetation patterning.  Geological formations range from sandstone-shale complex to serpentinite.  Soils range from fine textured soils in some of the floodplain and grassland areas to rocky soils on the steep hillsides covered by coastal scrub and chaparral.  The natural vegetation of the Poly Canyon is composed of a mosaic of grassland, coastal scrub, chaparral, coastal live oak woodland, and riparian woodland.  The hillsides surrounding Poly Canyon are mostly a mosaic of rocky outcrops, coastal scrub, chaparral, and coastal live oak woodland although grassland dominates most of rolling hills especially in the eastern portion of the canyon.  Human influenced communities such as ruderal (roadside) communities occur along Poly Canyon Road.  Blue gum eucalyptus, pepper trees, olive trees, and other exotics have been planted or have naturalized along portions of Poly Canyon near the campus and are mixed with the native vegetation.

The photograph below, taken by Steve Marx and used with his permission, shows Poly Canyon and its watershed.  The headwaters and eastern boundary of Brizziolari Creek is near the top of Cuesta Ridge which is shown at the very top of the photo.  Note the gentle terrain at the mouth of the creek as it enters the main campus (bottom of photo) and the mosaic of vegetation that occurs in the watershed.  The riparian woodland lines Brizziolari Creek at the bottom of Poly Canyon and forms a corridor of woodland vegetation over much of the length of the creek.

The photograph below shows the topographic of the areas around Brizziolari Creek and shows the location of Poly Canyon in relation to Cal Poly's main campus.  Notice the narrow contour lines in the canyon near the campus and the more open contours upstream toward Cuesta Grade.  The slopes of Cuesta Grade again become very steep.

The photographs below shows the mosaic of vegetation on the hillsides on and below Cuesta Ridge.  Notice the sharp boundaries (ecotones) among grassland, chaparral, riparian, and coast live oak woodland communities.  Riparain communities are restricted to areas along the creeks and some drainages, coast live oak woodland occurs in canyons and north facing slopes, coastal scrub and chaparral occur on steep, dry slopes with rocky soils, and grasslands occur on the more gentle hillsides where soils are usually deeper and often composed of more clayey, finer textured soils.  The roads and railroad track on Cuesta Ridge is also very visible. Photographs by Steven Marx and used with his permission.

The photographs below were taken from the ridge above the Poly 'P' facing eastward up Poly Canyon. The structures in the bottom left of the top photograph are the Peterson Ranch buildings.  Notice in both photos that the riparian woodland forms a well developed corridor of woodland vegetation immediately along the creek and bottom of the canyon.  Coast live oaks restricted to the mesic cayons, drainages, and north facing slopes in the upland areas above the creek but also join with the willows, sycamores, and cottonwoods to form the riparian woodland in this area.  Coastal scrub and chaparral are on the steep, dry slopes, and grassland is the dominant plant cover on the rolling hills.

Poly Canyon offers a unique opportunity for students to study the diversity of plants and animals and diversity of plant communities and wildlife habitats that occur along the central coast in a short walk from the main campus.  Most people are surprised that such a tremendous biological diversity exists in the canyon so close to campus.  The purpose of this web page is to introduce the reader to the diversity of plant communities and the diversity of plants and animals that occupy these habitats.  As you explore the canyon through this web site you will learn about several plant communities and the common plants that occur in these communities.  We encourage you to visit Poly Canyon and take advantage of this wonderful biological resource just a short walk away from the main campus.

Communities encountered as one explores this beautiful canyon includes:  Coast Live Oak woodland, Coastal Scrub, Grassland, Chaparal, Rock Outcrop, Ruderal, and Riparian.  Below is a list of links to the plant communities found in Poly Canyon.  Within each community you will learn some general features of the community and be able to view some of the common plants that grow in each by following the links.  If you have suggestions on how to improve this site, please let us know at vholland@calpoly.edu.

Additional note: The information contained in the community links was obtained from the book California Vegetation, written by V.L Holland adn David J. Keil. The community links are brief summaries of the sections found in the book. For more information on these and many other plant communities encountered throughout California, please consult the book!!  Have fun and I hope this will help in your explorations!!