Coastal Sage Scrub
The native habitat of Cal Poly Pomona is coastal sage scrub, and this habitat is also well-represented at BioTrek. It is called “coastal” because it is common in coastal areas of California (in our region, it penetrates the farthest inland). It is called “sage” because it is dominated by sages (Salvia), sagebrushes (Artemisia), and other aromatic plants. Like most California habitats, coastal sage scrub has wet winters and dry summers, and is heavily affected by fire. Unlike chaparral, our other common scrub community, coastal sage scrub consists of shrubs and trees of varying height.
Across the street from the Ethnobotany Learning Center is a portion of our remaining walnut woodland, which includes on campus some of the best remaining groves in the area. Our southern California black walnut (Juglans californica) is distinct from both the northern California walnut (its close relative) and the “English” walnut (actually from south Asia) which is widely planted.
Like walnut woodland, oak woodland is dominated by a single tree species, in our area the coast live oak (Quercus agrifolia). Unlike the walnuts, these oaks are evergreen, and only a few herbaceous plants grow in the shade of their canopies. They are also fire-resistant; our native oak woodlands easily survived the fires of 1981 and 1989.
Chaparral replaces coastal sage scrub on mountain slopes. In chaparral, the shrubs are of more even height, and often more tightly packed. BioTrek has representatives of all the dominant species of chaparral: chamise, redshank, manzanita, and California lilac.
Wetlands and Rivers
Today, we think of southern California as a dry environment, but that is because we use the groundwater in farms and cities, and channel the floodwater to the sea. Once, great marshes covered large parts of the region, some with permanent lakes, and the rivers and streams were filled with water, both above and below their sands. In these lands were vast forests of willow and cottonwood, and marshes of tule and cattail. A very small part of these still exists, but it is one of the most threatened habitats in California.
Islands and Coast
The Tongva travelled between the mainland and villages on Pimu (Catalina Island), Kinkipar (San Clemente Island), and the other southern Channel Islands. Their neighbors the Chumash lived on the northern islands. These islands, and some areas of the mainland coast, have a unique flora with species found nowhere else. The Channel Islands have been heavily impacted by grazing of cattle, sheep, and goats, but with the removal of these animals, they are slowly recovering.
In the mountain canyons are bigleaf maple and canyon live oak, and on the slopes are forests of Jeffrey pine, incense cedar, and black oak. North along the coast are the redwoods; the Tongva traded for redwood planks that they used to build their sea-going canoes. California forests are often a mix of conifers, broad-leafed evergreen trees, and deciduous trees. Although they are much less diverse than the forests of the tropics, some of them are among the most diverse habitats in California.
In this region, deserts are “on the other side of the mountains”, in their rain shadow. Further south in Baja California, they reach the coast, part of the large band of “latitudinal deserts” at 30° N and 30° S of the equator. California deserts sometimes get summer rain from the east (the same mountains that keep the Pacific storms from the desert hold these summer storms away from the coast). Desert plants and animals often have specialized adaptations for their dry habitat.
Toward the Tropics
The Ethnobotany Learning Center includes an area near the rainforest greenhouse that is planted with species from the deserts and tropical thorn scrub of western México. As well as being important to the indigenous people of those regions, these species form a connection to the tropics.