State 1
Reference State - Plant Community 2.1

Community 1.1
Reference State - Plant Community 2.1

Figure 4. manzanita chaparral

This state is similar to the historic state, PC 1.1 and is still dominated by Channel Island scrub oak (Quercus pacifica) and Santa Cruz Island manzanita (Arctostaphylos insularis). However, it is now intermixed with a non-native annual grassland understory, which is common throughout California. The primary invading 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 occurs under a fire regime of approximately 70 to 200 years, with lightning being the primary ignition source. 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 understory dominated by invasive annual grasses. Community Pathway 2.1b: The shift from PC 2.1 to PC 2.3 occurs if fires become more frequent (less than 10 year intervals). Extensive grazing by livestock and non-native wildlife can also push PC 2.1 towards PC 2.3.

State 2
Historic State - Plant Community 1.1

Community 2.1
Historic State - Plant Community 1.1

This historic community is represented by Channel Island chaparral and is dominated mostly by Channel Island scrub oak (Quercus pacifica) and Santa Cruz Island manzanita (Arctostaphylos insularis). It is found on drier convex slopes and has a more open canopy than its neighboring chaparral community found on the concave positions which is dominated by Channel Island scrub oak and toyon (see R020XI110CA). 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. 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). Non-natural grazing by livestock and non-native wildlife can also push PC 1.1 towards PC 1.3.

State 3
Plant Community 1.2

Community 3.1
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. Island mountain mahogany (Cercocarpus montanus var. blancheae), toyon (Heteromeles arbutifolia), chamise (Adenostoma fasciculatum), Channel Island scrub oak (Quercus pacifica), and probably Santa Cruz Island manzanita (Arctostaphylos insularis) will all resprout from the root crown. Some species will produce abundant seedlings including the chamise, and possibly the ceonothus species. 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 4
Plant Community 2.3

Community 4.1
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 shift 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 5
Plant Community 1.3

Community 5.1
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 extreme 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 6
Plant Community 2.2

Community 6.1
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 scrub oak and Santa Cruz Island manzanita 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 Channel Island scrub oak and Santa Cruz Island manzanita 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 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 scrub oak or Santa Cruz Island manzanita present. Extensive restoration efforts could transition this state back to PC 2.2.