11/10/2010
Biome Examples
Non-Forested Biomes
Today’s:
• Logistics:
– Midterm III – Tuesday, November 16th!
• Review Tuesday Lecture
• Finish Biomes
Photo: A. Holz
Review:
• What is a biome?
– Large (global patterns), stable terrestrial ecosystem characterize
by a specific plant and animal communities
– Named after dominant vegetation
– Biomes can have disjunctive or separate distributions,
– Assemblages of different, but similar looking species
– Rooted in the idea of “climax vegetation” **Climax = final
steady state
– Today, most ecologists think of ecosystems as dynamic, rather
than reaching a stable state
– Thus, Biomes integrate concepts like disturbance and the
modification of disturbance regimes by humans
Review:
• Criteria and/or Characteristics in
different biomes
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Vegetation structure: shape, layers
Productivity (Biomass)
Biodiversity
Distribution: geographic extent
Climate: temperature and precipitation
trends
– Soils
– Disturbance regimes
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11/10/2010
Mediterranean Shrublands
Mediterranean Shrublands: Structure
• Shrubs
• Dominant species: Chamise, Ceanothus,
Mountain Mahogany, Oaks
• “Sclerophyllous” Vegetation: hard leathery
leaves
• Leaves are evergreen or drought-deciduous
and generally very small
Photo: Dr. Susan Beatty
Coastal Sage Scrub
Photo: Dr. Susan Beatty
Coastal Sage Scrub
Photo: A. Holz
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11/10/2010
Chaparral
Mediterranean Shrublands (Chaparral):
Distribution
Photo: Dr. Susan Beatty
Disjunct locations (5)
located on west coasts of continents between
30-40 degrees latitude
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Heath: near Perth, Australia
Southern California: Chaparral, C.S.S.
South America (Chile): Matorral
Australia: Heath
South Africa: Fynbos
Mediterranean Sea: Maquis or Matorral
Photo: Dr. Susan Beatty
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11/10/2010
Matorral: near Santiago, Chile
European (Mediterranean Sea Region) equivalent of Coastal Sage Scrub,
Photo: A. Holz
Mediterranean Shrubland
Climate: Santa Barbara, CA
Temperate Rain Forest
Climate: Aberdeen, WA
photo: Dr. Susan Beatty
Mediterranean Shrublands: Disturbance
• Landslides, Floods
• Fire is very important!
– Frequent fires
– Re-sprouting shrubs (quick return interval)
– “Fire Followers”
• Human disturbances: clearing for
development, changing fire regime
(suppression vs. acceleration)
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11/10/2010
 Re-sprouting
shrubs after a burn
Chaparral after a
burn
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Prescribed burn, San Dimas Experimental Forest, California.
Photo: Dr. Susan Beatty
Photos: Dr. Susan
Beatty
Mediterranean Floristic Element
Mediterranean-like shrubs exist in
other biomes in smaller numbers
Chaparral: 2 years after a burn: “Fire Followers”. Photo by Dr. Susan Beatty
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11/10/2010
Mountain Mohogany (Cercocarpus montanus), Colorado Front Range
Ceanothus velutinus, Medicine Bow Mountains, Colorado
Deserts
Deserts
Characterized by very low precipitation
• Warm vs. cold
deserts
• Case studies of
North American
Deserts
Desert in Monument Valley, Arizona
Photo: A. Holz
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11/10/2010
Deserts:
Distribution
Warm Deserts
• Lower latitudes, warmer temperatures
• Subtropical High Pressure Zones
• Moderately Complex Structure
– Shrub layer
– Annual grasses and forbs (after rains)
– “Tree” layer: Saguaro cacti, Joshua Trees
•Subtropical High Pressure Zones (20-35
degrees N and S)
• Moderate biodiversity
• Low productivity, low biomass
•Rainshadow areas of Mountain Ranges
Cold Deserts
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North American Deserts
Cold Winters, Warm Summers
Rainshadow Deserts
Low diversity, productivity, and biomass
Lacks a “tree” layer
Few cacti
Dominated by shrubs and grasses
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11/10/2010
Chihuahuan Desert
Chihuahuan Desert
• Warm Desert
• Yuccas, Creosote Bush
• Summer high
precipitation
(Monsoon)
• Texas, New Mexico,
Northern Mexico
Neil’s picture
Big Bend National Park, Texas
Sonoran Desert
Climograph, El Paso, Texas
Century Plant, Big Bend N.P., TX
Sonoran Desert
• Warm Desert
• Arizona, California,
Northern Mexico
• Two precipitation highs
• High biodiversity
• Lots of large cacti
– Saguaros
– Organ pipe cactus
Climograph, Tucson, Arizona
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11/10/2010
Mojave Desert:
Joshua Trees
Mojave Desert
• Warm/Cold Desert
• Southeastern California,
Southern Nevada,
Northwestern Arizona
• Creosote Bush
• Joshua Trees
• Winter high Precip.
Mojave National Preserve,
California
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Climograph, Needles, California
Neil’s picture
Great Basin Desert
Creosote Bush
Larrea
tridentata
• Cold, rainshadow desert
• Winter high precip.
• Sagebrush, Rabbitbrush,
Greasewood
• Eastern Oregon, Nevada,
Utah, parts of Idaho and
Wyoming
Climograph, Gerlach, Nevada
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11/10/2010
Deserts: Cheat Grass (Bromus tectorum)
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Invasive exotic species
Grows between shrubs
Highly flammable
Shrubs burn, don’t come back
Cheat Grass thrives with fire
Sagebrush shrubland  Cheat grass
A “positive feedback”
Neil’s picture
Basin Big Sagebrush (Seriphidium tridentatum) Reville Range, Nevada
Temperate Grasslands
Tallgrass vs.
Shortgrass
prairie
A precipitation
gradient
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11/10/2010
Grassland: Distribution
Tall Grass Prairie
• Grasses and Forbs
• Historically maintained by fire (2-4 year
interval)
• Without fire, may become a deciduous forest
• Moderate to low biomass, but high
productivity
• Best soils in the world (Mollisols)
• Dominated by agriculture
Short Grass Prairie
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Dominated by short grasses, forbs and shrubs
Drier than Tall Grass Prairie
Less fire because less fuel
Soils productive, not as rich as tall grass
Biomass and productivity fairly low
Grazing and agriculture (irrigation needed)
Big Bluestem, Andropogon gerardii
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11/10/2010
Arctic and Alpine Tundra
Grama grass prairie with yucca,
Western Nebraska
Alpine Tundra: Medicine Bow Range, Colorado
Photo: A. Holz
Tundra: Properties
• Vegetation consists of grasses, sedges, forbs,
and low shrubs (willows)
• Biomass and productivity are low
• Biodiversity is low/moderate
• Vegetation adapted to extreme cold
Arctic vs. Alpine Tundra
Arctic Tundra
• High latitudes
• Precipitation may be
low
• Permafrost soils
• Surface soils are wet
• Extreme cold winters
• Large temperature
ranges
Arctic tundra
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11/10/2010
Alpine Tundra
•High altitudes
Arctic and Alpine Tundra: Distribution
•Precipitation tends to
be high (mountain
snows)
•Large temp range
•Wind disturbances
Photo: A. Holz
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