State 1
Reference State - Plant Community 2.1

Community 1.1
Reference State - Plant Community 2.1

This state is similar to the reference state, PC 1.1 and is still dominated by Channel Island mixed chaparral, but now has an understory of non-native annual grasses and forbs. The non-native annual grassland community is common throughout California. The primary species are slender oat (Avena barbata), wild oat (Avena fatua), ripgut grass (Bromus diandrus), soft brome (Bromus hordeaceus), and Spanish brome (Bromus madritensis). Community Pathway 2.1a: The shift from PC 2.1 to PC 2.2 historically occurred under a fire regime of approximately 70 to 200 years, with lightning being the primary ignition source. However, fires have generally increased to 40 to 50 years due to an increase in human-caused fires since the arrival of European settlers. Fires result in a decrease in shrub cover and an increase in the non-native understories dominated by non-native annual grasses. Community Pathway 2.1b: The transition from PC 2.1 to PC 2.3 occurs if fires become more frequent (less than 10 year intervals). Non-natural grazing by livestock and non-native wildlife can also push PC 2.1 towards PC 2.3.

State 2
Plant Community 1.2

Community 2.1
Plant Community 1.2

This state is dominated by native grasses and annual forbs, which will grow well while the canopy is open during the first couple of years following a fire. Most of the dominant shrub species are able to rapidly recover and grow after a fire, which will eventually lead back to PC 1.1. Community Pathway 1.2a: The shift from PC 1.2 back to PC 1.1 generally occurs after an extended period of time without disturbance from fires or grazing. After a fire, toyon (Heteromeles arbutifolia), hollyleaf cherry (Prunus ilicifolia), and probably Channel Island scrub oak (Quercus pacifica) and lemon sumac (Rhus integrifolia) will resprout from the root crown. Lemon sumac will also produce abundant seedlings. As the shrubs continue to increase in size and cover, they will eventually shade out the grasses and forbs in the understory and lead back to the pre-fire canopy cover of PC 1.1. Community Pathway 1.2b: The shift from PC 1.2 to PC 1.3 will take place under continued grazing or frequent fires (less than 10 year intervals). These disturbances will hinder the new growth of shrubs, leading to a state dominated by native perennial and annual herbaceous species.

State 3
Historic State - Plant Community 1.1

Community 3.1
Historic State - Plant Community 1.1

This community is represented by Channel Island mixed chaparral and is dominated mostly by Channel Island scrub oak (Quercus pacifica) and toyon (Heteromeles arbutifolia). Other common plants include summer holly (Comarostaphylis diversifolia), hollyleaf cherry (Prunus ilicifolia), and lemon sumac (Rhus integrifolia). It is found on concave positions and has a denser canopy than its neighboring chaparral community found on the convex positions, which is dominated by Channel Island scrub oak and Channel Island manzanita (see R020XI108CA). Community Pathway 1.1a: The shift from PC 1.1 to PC 1.2 occurs under the natural fire regime of approximately 70 to 200 years, with lightning being the primary ignition source. Fire results in a decrease in shrub cover and an increase in the native perennial and annual herbaceous understory community. Community Pathway 1.1b: The shift from PC 1.1 to PC 1.3 occurs if fires become more frequent (less than 10 year intervals). Grazing by livestock and non-native wildlife can also push PC 1.1 towards PC 1.3.

State 4
Plant Community 1.3

Community 4.1
Plant Community 1.3

If frequent fire or heavy grazing continually impacts this site, the regeneration and growth of the shrubs will be greatly hindered. This will lead to a site dominated by native perennial and annual herbaceous species. Community Pathway 1.3: The shift from PC 1.3 back to PC 1.2 can occur after an extended period of time without disturbance from fires or grazing. Restoration efforts can also help to expedite the return of PC 1.2. Transition 1: Continued frequent fires and non-natural grazing by livestock and non-native wildlife can place a stress on PC 1.3. This pressure can give an advantage to encroaching non-native plant species and may lead to the invasion of non-native annual grasslands.

State 5
Plant Community 2.2

Community 5.1
Plant Community 2.2

This community is dominated by non-native annual grasslands, which will grow well while the canopy is open during the first couple of years following a fire. Most of the Channel Island mixed chaparral will recover and grow after a fire, which will eventually lead back to PC 2.1. Community Pathway 2.2a: The shift from PC 2.2 back to PC 2.1 generally occurs after an extended period of time without disturbance by fire or grazing. New shrubs will resprout and begin to increase in size and cover. Eventually, the non-native annual grasslands will start to diminish as they are shaded out by the shrubs. Community Pathway 2.2b: The shift from PC 2.2 to PC 2.3 will take place under continued grazing or frequent fires (less than 10 year intervals). These disturbances will hinder the new growth of shrubs, leading to a state dominated by non-native annual grasses and forbs.

State 6
Plant Community 2.3

Community 6.1
Plant Community 2.3

If frequent fire or heavy grazing continually impacts this site, the regeneration and growth of the shrubs will be greatly hindered. This will lead to a site dominated by non-native annual grasses and forbs. Community Pathway 2.3: The transition from PC 2.3 back to PC 2.2 could occur after an extended time without disturbance, and in conjunction with restoration efforts. Transition 2: Continual grazing as well as frequent fires occurring more often than the natural range could transition PC 2.3 into a long term state.

State 7
State 3 - Plant Community 3.1

Community 7.1
State 3 - Plant Community 3.1

This state is dominated by non-native annual grasses and forbs with no Channel Island mixed chaparral present. Extensive restoration efforts could transition this state back to PC 2.2.