Thermic Ultramafic Foothills Moderately High Magnesium Content (Ca:Mg Ratio 0.5 To 2)

Description

State 1 represents the historic range of variability for this ecological site. Ultramafic soils often offer a refuge to many native endemic herbaceous species (e.g. red hills soap root plant (Chlorogalum grandiflorum; Calflora.org, 2016) because its unique soil chemistry is not amenable to the vast majority of plant species. Some of the endemic plants are still intact, despite the introduction of a number of annual grasses and forbs arriving after the discovery of the New World. However, most of the plants found in this ecological site can also be encountered in non-ultramafic soils. They are indifferent to the harsh soil conditions found in ultramafic areas and not great serpentinite indicators (See Bodenvag plants, Kruckeberg, 1984).

The different community phases below differ slightly in hydrological function and nutrient dynamics. For example, the post-fire phase (community phase 1.2) is more vulnerable to erosion, especially when significant precipitation events occur in the months following the fire. Within 2-3 years, there is generally enough plant cover to retain the soil. Community phases 1.1 and 1.3 are generally more stable and are less prone to erosion. However, it must be recognized that many of these ultramafic bands occur on undulating and less steep soils (< 35%), and thus do not pose as great a threat as chaparral communities in other ecological sites with more relief.

Submodel