ch 5 biogeography

Biogeography: Distribution of Plants and Animals

Chapter Five

California: Living Laboratory

• Enormous– Where do we start?– How do we organize

our study?– How do we classify

the various environments?

• Debates revolve around the diversity, connections, and change.

California: Living Laboratory

• Diversity– Wide range of

latitude– Elevation– Position within

subtropical and mid-latitude west coast

Biomes

• Large regional ecological units, or subdivisions of plants and animals.– Biomes are the largest

recognizable terrestrial ecosystems.

– Biomes serve as a starting point in the study of California Biogeography.

Ecosystems

• Represents a group of interacting organism and the physical environment in which they live.– Provides only the most

general categories and associations of California’s plants and animals.

www.goodnaturepublishing.com/Aspen.htm

Habitats

• Knowledge of habitats is critical to understanding California’s biogeography.– Habitats include a

combination of physical factors that represent the environmental conditions in which organisms live.

California Biomes

• Forest Biome

• Scrub Biome

• Grassland Biome

• Desert Biome

• Tundra Biome

Forest Biome

• The most productive biome, with the largest biomass (total weight of organisms)– Occur where

there is water and temperatures are not too extreme.

Forest Biome

• Temperate coniferous forest– Needle leaved

• Temperate deciduous forest– Broad leaved often

found mixed with coniferous forests in California

Scrub Biome

• Includes environments from coastal scrub to chaparral and even into oak woodlands.– Some consider this

another biome, a dwarf schlerophyll forest (dry Mediterranean Forest).

– The oaks might be considered park of the savannah biome (grassland)

Grassland Biome

• Includes most of the cismontane inland valleys even where it is hot.

Desert Biome

• Includes most of transmontane California.– Extreme drought– Extreme

temperatures– Low biomass– Low species

diversity

Tundra Biome

• Only in the high elevation environments– Cold temperatures– Short growing

seasons• Limiting factors

Connections…

• General connections can be made when comparing California’s biomes, vegetation structure, and habitats to other regions of the world:– Mediterranean Scrub: like

Chile, South Africa, Australia, and the Mediterranean

– Coastal fog, fires, mountains

– Similar adjacent forests and deserts

http://www.metoffice.gov.uk/education/teachers/mediterranean_climate_averages.html

Gocek, Turkey

Santiago, Chile

Perth, Australia

Vegetation Zones• Vegetation zonation by elevation

• Use plant communities to paint a pictures of California’s landscape.

Living Communities

• Ecological succession: continual process after each event or disturbance.– Primary versus secondary

• Climax community is in equilibrium so that it can maintain itself until the next event or disturbance.

Communities of Cismontane California’s Lower Elevations

• Coastal Sand Dune and Beach Communities– Beach: the strip of coastline

above the mean tide, inland to the greatest extent of storm waves.

• Plants and animals must adapts to waves.

– Coastal Sand Dunes: may extend well inland.

• Plants and animals must adapt to shifting sands.

– Coastal Strand and Littoral Strip are terms used to describe both the beach and the dunes.

Communities of Cismontane California’s Lower Elevations

• Habitat and Structure– Marine air:– Moderates temperature

and brings in moisture– Prone to rain and fog– Salt – Wind– 23% of California’s

coast is beaches and dunes, but plant communities make up less than 1% of land surface.

Communities of Cismontane California’s Lower Elevations

• Coastal Scrub Communities• AKA Coastal Sage or Soft

Chaparral– Similar to chaparral but smaller

plants with softer leaves– From Oregon to Mexico along

our coasts, into the coast ranges in the south.

– Adapted to frequent fires.

Communities of Cismontane California’s Lower Elevations

• Coastal Scrub Habitat and Structure– Mildest temperatures, daily and

seasonally.– Wide variety of species from

south to north, north gets more rain.

– Frequently blends into dune communities, woodlands, grasslands, and chaparral, includes succulents in the south.

– 2.5% of California’s coast-many endangered plants and animals

– Pressure from coastal development.

Communities of Cismontane California’s Lower Elevations

• Grasslands– Originally about 13% of California, especially

inland valleys

Communities of Cismontane California’s Lower Elevations

• Grasslands Habitat and Structure– Less precipitation than

surrounding higher terrain.

– Long, hot summers: where trees and shrubs do not survive.

– California’s Kansas: similar to Great Plains

– Large grazers: tule elk and pronghorn antelope

Communities of Cismontane California’s Lower Elevations

• Chaparral– Covers 10% of

California– All over the hills of

Southern California– Foothills of the

Sierra Nevada, Southern Coast Ranges, dry spots in Northern California

Communities of Cismontane California’s Lower Elevations

• Chaparral Habitat and Structure– Model Mediterranean drought

adapted plant community.– Sclerophyllous refers to the hard

leaves which are often small with waxy or resinous coating and fine hair.

– Leaves may also curl or be oriented to decrease direct sunlight-keeps transpiration rates down during summer drought.

– Evergreen 800+ species – Adapted to fire (succession) – Pryophyte: only germinate and

grow after fire

Communities of Cismontane California’s Lower Elevations

• Mixed Evergreen Forest– Transition between oak and chaparral– Coastal mountains of the north, southern

coastal mountains– 5% of California

Communities of Cismontane California’s Lower Elevations

• Mixed Evergreen Forest Habitat and Structure– Hardwoods,

especially oaks, keep leaves all year, mixed with conifers

– Chaparral mix

Communities of Cismontane California’s Lower Elevations

• Coastal Coniferous Forest Communities– Oregon to Big Sur– Southern extension of

temperate rainforest.– Contains the redwoods– Habitat: located just

inland from ocean to western slopes of the Klamaths and Central Coast Ranges.

– Average 100 inches of rain per year

Montane Coniferous Forest Communities

• Grow on mountain slopes– From 1,000 feet in the

north• Between wetter forests

to the west and drier communities in the east.

– From 5,000 feet in the south

• Patchy high country in the Transverse and Peninsular ranges

Montane Coniferous Forest Communities

• Occurs above chaparral and oak woodlands– Cooler, more

precipitation– Higher elevation,

sparser. Less precipitation.

Montane Coniferous Forest Communities

• Mixed/Lower Montane Coniferous Forests– About 10% of California– Trees about 200 feet

(tallest)– Mixed with oaks – Undergrowth ranges

from sparse to thick– Transition zone

Red Fir and Lodgepole Pine Forest/Upper Montane Forests

• Higher elevation• Colder temperatures,

heavy snow, short growing season

• Lodgepole dominant above 8,000 feet.

• Red Fir needs more moisture– Lodgepoles grow at

lower elevation in drier areas where Red Fir will not.

Subalpine Forests

• All creatures must be adapted to long, extremely cold winters-summer 7 to 9 weeks long.

• Above 6,500 feet in Klamaths

• Above 10,000 feet in the Cascades and Sierra Nevadas– Upper limit is the tree

line

Alpine Communities• Isolated islands above the tree

line• Terrible cold and wind create

very harsh conditions.• Around 7,000 feet in the north,

about 11,000 in the south• Mt. San Antonio and San

Gorgonio in the Transverse Ranges and Mt. San Jacinto in the Peninsular Ranges.

• Most north of southern California were covered in glaciers during the Pleistocene.

Riparian Communities

• Located on or adjacent to a river bank or other freshwater body.

• Water availability is the most important limiting factor.

Riparian Communities

• Lots of variety: streams in narrow strips, wide in flood channels of rivers, 10 miles wide in the Central Valley.

• Tall shrubs, small trees, towering giants

• Moist, cools, shady, protected environments.

• Dramatic differences in Southern California to surrounding dry land.

Transmontane Deserts

• California’s great physical barriers

• Rain shadow deserts

Transmontane Deserts

• Pinon Pine and Juniper Woodland Communities

• 4,000-8,000 feet in the desert

• 3% of California• Below coniferous

forests

Transmontane Deserts

• Mixed dwarf forest

• Winter snow

• 20 inches of precipitation per year

• Most plants related to Great Basin and Colorado Plateau species

Joshua Tree Woodlands

• Found at 2,000 to 5,000 feet from Southern Owens Valley through the Mojave Desert into Nevada and Arizona.

• Tolerate frost and occasional winter snow.

• Do not grow in the hot valleys of the desert.

Joshua Tree Woodlands

• Species from many other communities grow with them.

• Merge into juniper woodlands at higher elevations, creosote lower, sagebrush north.

• Carpet of wildflowers and grasses underneath in wetter years-lasts only a few weeks, dries and goes to seed.

Desert Scrub Communities

• Vast open expanses of desert scrub covers about 30% of California.

• Lack of water-limiting factor

• Hot summers, cold winters

• Harsh environment, too harsh for trees

Desert Scrub Communities

• Sagebrush Scrub– Northeast deserts, higher elevations 4,000-9,500 feet

• Blackbush Scrub– Lower elevation, below sagebrush

• Shadescale Scrub– Between sagebrush and creosote scrub, alkaline soils

• Saltbush Scrub– Higher salinity soils of lower desert plains and basins

• Alkalai Sink– Most salt tolerant halophytes, lower basins of Basin and Range

• Creosote Bush and Cactus Scrub– Creosote oldest plant, tolerates heat and drought, but not cold-

middle to lower elevations of Mojave Desert

Sagebrush

Blackbrush

Shadescale Scrub

Saltbush Scrub

Alkali Sink

Cactus Scrub

Burrowing Owl

Desert Wash, Riparian, and Oasis Communities

• Water may only flow briefly, then disappear under the surface but is still available to root systems.

• Dense thickets or thin strips