The coastal strip of San Diego has a long growing season resulting from its maritime influences and Mediterranean climate of mild wet winters and warm dry summers. The temperature ranges from a January minimum of 45 °F to an August maximum of 80 °F, with a yearly average of 62 °F. The majority of rainfall comes during the winter and early spring, with a seasonal average of less than ten inches.
Blankets of coastal fog also add moisture to this semiarid desert environment via the condensation of water on the plants and soil. Fog also increases the humidity of the air, lowering the plants’ evaporation rate, which is especially vital during summer. It is common for fog to persist the entire day along the coast while temperatures inland soar, especially during June and July.
These environmental conditions vary as the marsh transforms into upland plant communities. Thus, a vertical pattern of plant distribution occurs, with different species being abundant in different zones.
The salt marsh is a highly productive ecosystem, making it an extremely important wildlife habitat. It serves as a nursery for fish and shellfish and a feeding and nesting ground for resident and migratory birds.
The common species include Salt Grass (Distichlis spicata); Pacific Pickleweed (Sarcocornia pacifica); Parish’s Pickleweed (Anthrocnemum subterminale); Pickleweed (Salicornia depressa); Alkali Heath (Frankenia grandifolia); and various species in the Amaranth family.