The Elfin Forest supports diverse natural plant and animal communities because of its very special combination of geologic, soil, and climatic environments. Most of the habitats in the Natural Area pose both severe survival problems for plants and animals and also rare opportunities for species that are adapted to these environments.
A little over a quarter of the Elfin Forest lies in tidal lands of Morro Bay estuary. Plant species living in the marsh area are specially adapted to tolerate repeated flooding, drying, and varying degrees of salinity. Soil salinity rather than flood water salinity is the major determinant of what plants thrive in different parts of the marsh. Salinity is modified by fresh water coming down Los Osos and Chorro Creeks and springs at the base of the sand dunes. Where soil salinity is high the Coastal Salt Marsh Community is found – predominately Pickleweed and Saltgrass. Lower salinity yields the Brackish Water Marsh Community – dominated by rushes and sedges. The demarcation between salt and brackish water marsh is not clear cut. Bordering the marshes, and above the high tide line, is the Riparian Woodland Community, where trees such as Sycamore and willows are able to survive because of fresh water coming to the surface.
