and Coastal Sage Scrub
Chaparral: Communities of evergreen sclerophyll shrubs that develop where Mediterranean climates prevail
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:
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
Fog and overcast
Where not on coast, this would be desert scrub
Coastal Scrub Sage species
All of the sub-shrubs and suffrutescent species of the chaparral, plus:
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.
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).
Herbaceous and suffrutescent species grow back abundantly after fire.
Shrubs grow back after four years from seeds or sprouting
Plants resprout and flower first year
Seed crops result in a huge seedling recruitment in the second year.
Wilkins, K. 2009
Chaparral species planted into a closed quarry
Fire enhances germination, post-fire.
Fire, heat and char were used.
Best treatment was Wrights 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.
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.
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.
Standard mitigation practice: nursery grown container plants (shrubs), plus hydroseeding or imprinted seeding.
Doomed sites can be harvested
Mature adult shrubs
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.
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
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)