Pacific Mountain System

Coast Ranges

North Coastal Ranges

South Coastal Ranges

Coast ranges

• Most Mountain peaks at around 4,000 ft.• 550 miles long (North & South)• Divided into Northern and Southern

Ranges at San Francisco Bay• Proximity to ocean on west slope, keeps

temperatures cool, and fog common –– Fog held there by mountains.

• Inland valleys, peaks have less coastal influences

North Coast Ranges• Run north of SF to Klamath Mountains, by

Eureka.• Heavy summer fog keeps soil moist along coast

– Adds up 10 inches of precipitation

• Inland valleys drier due to rainshadow– Bodega, Napa, Sonoma etc.

• Heavy Salt spray along coast• Include mostly North/South running river valleys

– Eel, Russian Rivers

• Older than Southern Ranges.• Includes higher peaks, some exceeding 7,000 ft.

North Coast Ranges

• Most Seismically active region in United States

• In the 1990s, at least nine magnitude 6.0-plus earthquakes jolted the North Coast.

• This amount of large quakes was higher than in any other decade within the last century.

Uplifting• West coast constant rising up over last

several million years.• Along with changes in sea level during Ice

Ages the uplifting of old marine / shoreline terraces are moved from 100 - 1000 ft. above sea level.

• Sedimentary layers get tilted in uplifting and when saturated they may give way, causing the frequent mudslides along southern coast.

Eroded Marine Terraces Montaña de Oro State Park

North Coast Marine Terraces

Northern Coastal Zones

• Pygmy forest: shallow soil with hard pan underneath in sandstone.– Water-logged in winter, dry in summer– Costal fog keeps trees alive– Restricted root growth stunts plants– Bolander Pine endemic species, Pygmy

Cypress grows there as poor competitor.

• Closed Cone pines on uplifted dunes- sandy soils, cool wet climate with fog.

Pygmy Forest

• Shallow soil• Hardpan layer restricts

root growth- stunting trees

• Small plants but old with mature cones, berries

• Needs heavy summer fog to prevent drying out

Northern Coastal Zones

• Rocky intertidal – ocean and land meet- high diversity of algae and animals.

• Dunes (strand) drought-adapted vegetation.– Vines, deep roots, shifting sands

• Coastal Prairie: first terrace, uplifted dune– Green year round, perennial wildflowers,

rushes, etc. Used for pasture for dairy cows

• Redwood forest – cool wet areas away from salt spray

Northern Coastal Zones• Mixed evergreen forest:

– Douglas Fir, Tanoak, Giant Chinquapin, Madrone, Bay, Coast Live Oak

• Yellow Pine- Jeffery Pine– High elevation or dry with serpentine

• Foothill woodland– Blue Oak inland, Oregon Oak in coastal slopes– Foothill pine, Buckeye, Redbud, – Coast / Interior Live on north slopes

• Riparian – Redwood, Bay, BL Maple, Doug fir, Torreya,

Dogwood, Alder , Willow

Biotic Zonation of North Coast Ranges

North Coast Range Geology:

• Arc islands that got accreted to North American plate during the late Mesozoic (65-150 million years ago).

• Has Franciscan rocks (shales and sandstones) formed by rapid erosion settling into marine basins, then uplifted as arc islands.

• Franciscan Rocks

sedimentary marine deposits uplifted

• Salinian Block formed south of Sierras, moved North 190 miles.

• Population of salamanders, newts traveled along with rocks

• Now isolated as separate species

Southern Coast Ranges

• Run from SF to Transverse Ranges, by Santa Barbara

• Some peaks reach 6,000 ft. Taller peaks in the southern end due to less erosion

• Larger, wider North - South valleys– Salinas River Valley– Nacimiento River Valley

• Strong slope effect: south-facing has dry chaparral, north-facing has evergreen oaks

South Coast Range Geology

• The Granitic rocks in the core formed as part of Sierra Nevada batholiths moved north up to 300 miles north by San Andreas fault activity over last 25 million years.

• Uplifting and placement of Southern Coast Ranges above sea level over last 1-2 million years, much more recent then Northern Ranges.

• Mainly composed of soft unstable sedimentary rocks easily eroded– Santa Cruz cliffs loose an average of a foot a year.– Maximum record was 75 feet in one storm season

Coastal erosion

Serpentine - an Edaphic (soil) ecological island

• Igneous rocks intruded into Franciscan rocks and metamorphosized by heat and sea water to green serpentine.

• named for serpent pattern of mottled snake skin.• rich in Mg and Fe; Ni, Co, Cr• low in Ca, Na, K• These minerals leeching from rock make root

function difficult for plants, causing water stress

Serpentine communities:

Poor competitors survive on serpentine:

In North Coast Ranges: chaparral with Chamise

In wetter areas: Closed Cone Pines, Jeffery Pine or Incense Cedar predominate

Specialists plants adapted to serpentine:

Leather oak

Interior Silktassel

Shrubby forms of California bay

Macnab Cypress in interior North Coast Ranges

Serpentine areas in California

Banana Slug- Our State MolluskVery common in moist Coastal forests

Monarch Butterflies

West of Rockies, Adults over-winter in coastal valleys from Bolinas, to Ensenada.

Eastern Monarchs migrate to central Mexico.

Only known insect that migrates over long distances.

3000 miles to MX

660 miles AZ to CA

Winters• Adults eat nectar- hard to find in winter inland,

easier along coast, Mexico• Adults migrate, basically going extinct in cold

areas over the winter.• Return to same trees as the previous year. Yet –

They are three or four generations removed from previous years monarchs!!– Migration is instinctive, not learned

• In spring they repopulate, laying eggs as they fly back north, west. Offspring then take over repopulation spreading the population back as winter retreats.

Migration Routes

Monarchs protected by Milkweed toxins eaten while larvae

Larvae (caterpillars) eat Milkweed, and accumulate the toxic cardiac glycosides. The Monarchs are immune but their predators are not.

Monarchs are protected by these compounds from being eaten in general. A few must be lost so birds learn to avoid them.

Predators (birds) learn to avoid adult monarchs by their coloration.