California Chaparral

and Coastal Sage Scrub

Chaparral:  Communities of evergreen sclerophyll shrubs that develop where Mediterranean climates prevail

–      Warm-temperate

–      Cool, moist winters

–      Hot, dry summers

–      80% of rain falls in winter

Chaparral, maquis, garigue

Found adjacent to, and inland from coast

Plants possess unifying adaptations:

–      Dense crowns

–      Sclerophylls

–      Wide spreading root systems

–      Adapted to fire

•       Heat scarified seeds

•       Sprouting from root crowns

Californian Coastal Scrub: 

–      Occurs below chaparral

–      More xeric, short-shrub community

–      Referred to as “soft chaparral”

–      Very dry climate (12 in/y) ameliorated by coastal location

•       Cooler

•       Fog and overcast

•       Where not on coast, this would be desert scrub

 

Chaparral species

–      Adenostoma fasciculatum

–      Arctostaphylos auriculata

–      A. glandulosa

–      A. glauca

–      A. pajaroensis

–      Ceanothus cuneatus

–      C. greggii

–      C. megacarpus

–      C. spinosus

–      Cercocarpus betuloides

–      Heteromeles arbutifolia

–      Quercus dumosa

 

Coastal Scrub Sage species

•       All of the sub-shrubs and suffrutescent species of the chaparral, plus:

–      Encelia californica

–      Baccharis pilularis

–      Viguera laciniata

–      Lepidospartum squamatum

•       Aromatic dominants:

–      Artemisia californica

–      Salvia mellifera

–      Salvia leucophylla

•       Most dominants are shallow-rooted sub-shrubs that lose their foliage in response to drought.

•       When water is available, they can grow twice as fast as chaparral species.

Fire

•       Wildfires are a dominant part of the environment.

•       Frequency averages once every two to three decades in natural systems.

•       More in human dominated systems.

•       Fires are big (thousands of hectares).

Fire Response

•       Chaparral

–      Herbaceous and suffrutescent species grow back abundantly after fire.

–      Shrubs grow back after four years from seeds or sprouting

•       Coastal scrub

–      Plants resprout and flower first year

–      Seed crops result in a huge seedling recruitment in the second year.

Restoration

•       Wilkins, K. 2009

–      Chaparral species planted into a closed quarry

–      Fire enhances germination, post-fire.

–      Fire, heat and char were used.

–      Best treatment was Wright’s Liquid Smoke and heat.

–      Increased germination of Adenostoma fasciculatum, Ceanothus cuneatus and Salvia mellifera.

•       Cione, Padgett and Allen, 2002

–      Restored fragment of coastal sage scrub in urban environment.

–      Site had been subjected to fire, anthropogenic nitrogen deposition and invasion by Mediterranean annual weeds.

–      Hand cultivation and grass-specific herbicides successfully controlled weeds.

–      Seeds were sown to replace depleted seedbank

–      Seeding succeeded in a wet year but not a dry year.

–      Green yardwaste mulch did not help

–      Shrubs began to exclude grasses by second year.

•       Stratton, 2004

–      Planting and seeding into abandoned ag fields on Santa Catalina Island

–      Problems: weeds, deer bison

–      Annual weed control, seeding and planting seedlings without protection were inadequate

–      Seedlings planted into wood chips were easy to see and were browsed.

–      Watering helped in dry years.

–      Use of native soil and oak litter increased acorn establishment.

•       Burkhart 2006

–      Deep one gallon containers showed much greater survival than liners or regular one gallon pots.

–      Species used were deep-taprooted species including Quercus agrifolia.

–      Growth surpasses five gallon pots, and planting is much easier and with lower production costs.

•       Allen et al. 2000

–      Coastal sage is becoming difficult to restore

•       Weeds, frequent fire, nitrogen deposition

–      Native shrub re-colonization is slow where Mediterranean annual grasses are present.

•       Bromus, Avena, Vulpia, Hordeum

–      Other weeds: Cynara, Carpobrotus, Chrysanthemum, Brassica, Erodium, Centauria, Feniculum, Nicotiana

–      Shrub restoration from seed not successful unless grasses are removed.

–      Seedlings of Artemisia californica succeeded; survival and growth rate were increased by weeding.

–      Anthropogenic nitrogen deposition from automobile exhaust favors weeds.

–      A regional strategy will select sites that are most likely to respond to restoration favorably.

•       Bowler, 2000

–      Standard mitigation practice:  nursery grown container plants (shrubs), plus hydroseeding or imprinted seeding.

–      “Doomed” sites can be harvested

•       Seed sources

•       Seedling collection

•       Mature adult shrubs

•       Soil

–      Restoration site values:

•       Seed sources…transplanted shrubs produce copious seeds crops

•       Seed crops produce lots of seedlings which may be harvested before they self-thin.

•       Instant habitat

–      Landscape mosaic of an intact community was used to design the restoration.

•       CSS is patchy, not continuous

–      Within restoration mosaic, patches of salvaged mature shrubs are placed within a matrix of imprinted seeding or containerized seedlings.

–      This allows early use by bird species and results in faster expansion of CSS.

–      Transplanted shrubs are removed from donor site and placed in restoration site during winter rainy season.

•       No additional watering is needed

•       Keeley 2002

–      Fire management in California shrublands is influenced by policies for coniferous forests.

•       It has not effectively excluded fire

•       Catastrophic wildfires are not the result of unnatural fuel accumulation

–      There is no evidence that prescribed burning has any resource benefit.

–      Therefore, fire hazard reduction is the primary benefit

–      Rotational burning to create a landscape mosaic is not a cost-effective way to control wildfires.

–      High fire frequency can extirpate species sensitive to short fire return intervals.

–      Some shrub communities have successfully weathered century long fire-free periods.

–      There are no examples where fire dependent shrublands are threatened by lack of fire.

–      The most cost-effective strategy for limiting catastrophic fires is buffer zone management.

•       Intensive management at the urban-wildland interface.

•       Buffer zones 1) prevent wildland fires from entering urban areas, and 2) limit ignitions arising from urban populations

•       Buffer zone types

–      Rotational burning to create younger age classes

–      Conversion to less hazardous fuel types (harvest)

–      Green belts

–      Denuded zone