Cismontane Abiotic Environment

What are Abiotic Factors?

Abiotic factors make up the abiotic environment and encompass all that which is nonliving. These features include and are not limited to temperature, light exposure, air, water, fire, the soil, and geologic structures. As such, these factors have direct impacts on nutrient availability and the ability for biotic factors -- flora and fauna -- to grow, thrive, and flourish.

Cismontane Climate

At a elevation range of 500 to 5,000 feet, California's Mediterranean climate is a key component as to why the Cismontane ecosystem is so biodiverse and endemic. The semi-arid climate entail hot-dry summers that can commonly be foggy and overcast. Summer temperatures range from the 80 to 90 degrees Fahrenheit, and can sometimes creep into the hundreds. However, during the cold-wet winter, temperatures can drop to as low as 30 degrees Fahrenheit. Precipitation typically ranges between 10 to 20 inches of rain annually. Generally, the mild climate allows for monthly flowering periods throughout most of the year as vegetation goes dormant in the dry summers.

Photo: Flickr

Geology and Soil

Photo: California Chaparral Institute

The geologic structures of the Cismontane ecosystem consist of a number of material including: dense Monterey Shale, red iron-rich gabbro, sandstone, volcanic soils, and greenish serpentine that is high in iron and magnesium. The metamorphic rock, serpentine, is old, marine sedimentary terrace and sustains habitat for 13% of California's endemic species as these geologic formations directly influence the consistency of the habitat's soil.

Cismontane soil consists of of a diverse set of soils from acidic, hard pan, sand to alkaline clay. Volcanic rock can be found near the base of the San Pedro Mountains and transitions into predominantly sedimentary rock as you move closer towards the coast, however, the soil is generally nutrient-poor throughout. The granules of these soils are often sandy, rocky, heavy, and gravel like. As a result, the soil is typically well drained as water percolates well into the watershed. Species such as Lichen near the coast are well adapted to these sandy soils as they not only stabilize the substrate, but also capture nitrogen for the surrounding flora.

Photo: California Chaparral Institute

Photo: USDA Forest Service

Water and Groundwater Resources

Although this ecosystem experiences seasonal events of flooding and drying over the annual cycle occur, water in this ecosystem can be quite scarce as annual precipitation is between 10 to 17 inches. Most of the water in this region originates from upland sources via streams and fog. Majority of the water in this habitat is stored underground and provides stability to the watershed and environment's hydrology. Vegetation in this ecosystem is well adapted to water scarcity through the development of water conservative traits such as their seasonally dimorphic leaves, deep tap roots, and thick, waxy leaves.

Photo: Los Angeles County Fire Department

Fire Ecology

Fires are necessary events as some of the native vegetation, both annual and perennial, depend on fire for reproduction, seed germination, and regeneration. Naturally, ground fires occur every 30 to 150 years. These fires not only germinate dormant seeds that are only stimulated by heat, but also provide nutrients to these sprouts and other flora that continue to persist through the fire.

However, through the introduction of more flammable invasive species, crown fires become dominant, ultimately leading to the demise of the native vegetation.

Wildfires in the Southern California region are highly correlated with not only the amount invasive species present, but also the presence of wind and the speed in which it is moving. Such as the Santa Ana Winds, these winds intensify the fire, ultimately causing significant loss of biodiversity.