Despite the obvious and abundant natural endowment of San Marcos Foothills (SMF), and all the studies appended to development proposals, no information has been systematically acquired on the birds or wetlands at the property, nor has any synthesis of the interactions of land, plants, and animals been undertaken.

This part of the Plan advances knowledge of San Marcos Foothills in three important ways. First, we call attention to the sophisticated ecological relationships that exist on site to demonstrate that processes occurring on and off the property offer the potential for long-term, sustainable biocomplexity. (See Map 2, Habitat Reservoirs and Connections.) Second, we present information on natural resources that is largely missing from previous studies (e.g. Santa Barbara Co., 1999). Finally, we point out opportunities for further study. These elements support our vision for education, research, restoration, and community participation in the stewardship of San Marcos Foothills.

Habitats
Within an ecosystem, and we view SMF as part of the larger foothills ecosystem, habitats contribute to ecosystem services. These services include soil stabilization, nutrient replenishment, and shelter, food, and breeding sites for members of the ecosystem. Wetlands perform specialized services such as water filtration, sediment retention, groundwater recharge, and creek bank stabilization.

Especially important in each habitat are the ways in which biological elements interact with non-biotic elements. Wet areas, for example, support snails, which concentrate calcium in their shells. When consumed by nesting birds, the shells provide a source of calcium used for egg production. These kinds of interactions occurring within habitats contribute to ecosystem complexity. On San Marcos Foothills, we identify eight distinct habitat types within which these interactions take place. (See Map 3, Vegetation.)

Each habitat acquires a distinctive character — the product of slope, aspect, soils, hydrology, pollinators, who got there first, and subsequent animal and plant interactions. Environmental conditions further modify the interactions that occur and the extent of support habitats provide. Extreme environmental events exert the greatest forces in shaping habitats. For example, intense pulses of rain followed by heavy runoff can wash away the seed bank. This reduces the germination of annual herbaceous plants and affects as well those small mammals and birds dependent on the seed production from annuals.

Delicately balanced as it is, what is played out on San Marcos Foothills is a model of the self-sustaining natural world from which we can learn much. After all, the human community depends on the benefits of healthy ecological functions. Many are critical to our economy, health, and standard of living. We rely so heavily on these systems that we can assign to them dollar value, and we spend considerable portions of our economy simply maintaining these ecosystems for harvestable commodities or for the services they provide. In the latter years of the 20th century, we learned that the failure to maintain systems vital to our well-being is not only costly but in some instances such ecosystems are impossible to recreate once lost.

In what follows, we introduce each habitat on San Marcos Foothills and discuss the botanical, animal, and functional attributes of each. The most convenient way to

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