Coastal Sage Scrub
Coastal Sage Scrub forms the intermediate community. Sages (Salvia) are the indicator species, and Santa Barbara County hosts black, white, and purple sage. The scrub shrubs have thinner and more flexible branches, softer and aromatic leaves, so this is often called the soft chaparral. They thrive where the minimum winter temperature is warm (greater than freezing around BMER) and relatively low total precipitation fifteen inches (40 cm) per year. Shrubs and subshrubs intermingle with native and alien grasses. They have shallow root systems and soft leaves adapted to reduce evaporation.
These sage scrubs definitely benefit from cooler coastal climate. But they are most often found on sloping grounds that promote more runoff, and thus more arid conditions. This may give them a competitive advantage over chaparral shrubs, and the transition from chaparral to scrub at a hillside can be abrupt. They also employ other strategies to conserve moisture, including waxy or spiny leaves. In addition, many shrubs are drought-deciduous—they drop some leaves in summer to conserve water, and grow new ones in the rainy season.
Black sage, California sagebrush, monkeyflower, and wildflowers, like golden yarrow, prickly phlox, and horkelia, comprise the Coastal Sage Scrub in BMER. They provide more food and cover for wildlife than grassland, but more freedom for wildlife movement than the hard or Maritime Chaparral. White sage and California buckwheat are common members in other regions of the state, but on Burton Mesa they seem restricted to a short path near Cabrillo High School. I suspect they have been introduced by local gardeners.
BMER has some Coastal Sage Scrub that lacks black sage. A trail starts in the 200 block of Oakhill Ave. and heads north into the reserve. The area slopes from north to south and is riven by deep gullies that make hiking or biking hard. About 100 yards from the street the trail splits, and the left path continues through sage scrub. The right path continues into shorter vegetation dominated by California sagebrush and chamise. Just 50 yards from the sage scrub, nary a black sage can be seen. It also has many tarweeds, both on top and in the gullies.
This scrub may intermingle with the maritime chaparral in a mosaic. In the story that these habitats are a cycle from grass to woods, eventually larger bushes may crowd out the shrubs and form the hard chaparral.
