Plant Communities of the Etiwanda Fan
Biotic (living) and abiotic (non-living) factors determine which plant community will persist in a given area. The major abiotic (non-living) factors include latitude (distance from the equator), altitude (distance above sea level), aspect (which direction the land faces which in turn determines sunlight intensity), slope, average temperature, temperature range, average precipitation, precipitation range, wind patterns, and local soil characteristics (acidity, moisture holding capacity, nutrient levels). The major biotic (living) factors include plants that are already present, how well adapted they are to the abiotic factors, and their ability to compete for limited resources such as water, sunlight, and nutrients. The plants of the Etiwanda Fan are adapted to the cool, wet winters and hot, dry summers of southern California and have over time formed a mixture of four major plant communities; Chaparral, Coastal Sage Scrub, Alluvial Fan Sage Scrub, and Riparian. The distribution of these communities on the fan is a result of small differences in the abiotic features and the history of that patch of land, including fire, flooding, and human disturbance.
The wildfires of October 2003 burned nearly all of the vegetation on the Etiwanda Fan. Not discounting the tragic loss of life and property, the fire on the Preserve and Etiwanda Fan is not the ecological disaster it might appear to be. Biological systems are dynamic and resilient. And, fire is a frequent and natural component to many southern California ecosystems. When left undisturbed after a major fire, the plant and animal communities on the Preserve and Etiwanda Fan will recover as they have always done in the past. Plant recovery can come from seed germination and crown sprouting. Many fire-adapted plants will re-sprout after a fire from the root crown at and below the soil surface. Re-sprouting can be immediate and generally results in the same pre-fire vegetative community. When fire intensity is high, root crowns may not survive the intense heat. In these instances, plant recovery comes from the existing seeds bank. In most fires, recovery of the vegetative community comes from both crown sprouting and seed germination. How long the recovery of the vegetation communities will take can be highly variable and heavily dependent on fire intensity, amount of annual rainfall, the timing of the annual rains, and the absence of further large-scale disturbances.
Coastal Sage Scrub
Alluvial Fan Sage Scrub