GEOG 2-Ecology and biomes

Habitat

the natural environment in which an organism lives

• Koalas live in coastal islands, tall eucalypt forests, and low inland woodlands

Macrohabitats

the large environments categorized by certain climate conditions and plants

Microhabitat

smaller in size, very local

• Feeling cooler in the shade vs. in the sun in the same habitat

How do we categorize biodiversity?

• Ecoregions

• Biomes

• Ecological Land Units

Ecoregions:

• Defined based on plants, landforms, soils, climate and more

• Used by Environmental Protection Agency (EPA)

• Split into 4 levels to define regions:

  • Level I: 15 ecoregions

  • Level II: 50 ecoregions

  • Level III: 182 ecoregions

  • Level IV: 1,000 + ecoregions

Landforms:

• Used in ecoregions, ELUs, and biomes

  • flat/smooth/irregular plains

  • Low hills

  • Hills

  • Low mountains

  • High mountains

  • Deep canyons

  • Surface water

Lithology:

• Used in ecoregions, ELUs, and biomes

  • Sedimentary rock (sandstone, shale)

  • Unconsolidated sediments (loose sands or gravels)

  • Evaporites

  • Metamorphic rock

  • Volcanics

  • Ice and glaciers

Land cover:

• Bare (no plants, plain ground)

• Urban areas

• Shrubland

• Grassland

• Cropland

• Forest, open space (space between trees)

• Forest, closed (dense tree canopy)

• Snow and ice

• Water (lakes, reservoirs)

Ecological Land Units:

• Defined based on: climate (temperature/precipitation), landforms, lithology, land cover

  • More specifically focuses on bioclimate

    • Water: fresh, salt, precipitation

    • Temperature: annual temperature and seasonal extremes

• Used by US Geological Survey and ESRI (geo mapping company)

• About 4,000 ELUs worldwide, based on a unique combination of these 4 factors

Biome:

• Very large-scale classification of habitat

• On land, defined along bioclimate axes (temperature and precipitation)

• In oceans, defined along axes of light/depth and distance to land

Tundra:

• Cold dry areas, between treeline and ice caps

• Species are unique and adapted to cold

  • Polar bears, arctic fox, lemmings

• Plants are low to ground

• Areas with fewest fires (cold, low fuel load)

• Frozen soil: permafrost

  • Permafrost locks up methane that could accelerate climate change if it melt

Deserts:

• Deserts are defined by precipitation

  • Less than 50cm a year, although many get less than 10cm

• Not a lot of vegetation, low productivity

  • Some seeds can survive waiting 100 years for rain to sprout

• Desert and semidesert cover ⅓ of earth’s land surface

• Most are between 20-30 degrees N or S where, where atmospheric circulation patterns mean the air is dry

• Can be cold or hot

Shrubland

• Shrubland:

  • Biomes have few trees but enough precipitation and warmth for moderate productivity of many other plants

  • Shrublands are about as productive as savanna

  • Hot and dry summers

  • Frequent lightning causes frequent fires → landscape is adapted to it

Grassland

• More productive than shrublands because grass grows quickly

• 80% of fires globally occur in grasslands (lots of fuel)

• Many of these ecosystems have been lost to agriculture over time

• Found on every continent except antarctica

Savanna:

• Hot and dry

• Mixed woodland and grassland

• Acacia trees in african savanna, eucalyptus in Australia

• More productive than tundra or desert, but still low productivity

• Some fire risk - dry and hot areas and plants for fire load

Boreal forest/taiga:

• Coniferous and broadleaf trees, not taller than 30m

• ¼ to ⅓ of all forests are boreal forest

• Half of all boreal forests are in Canada

• Needs to be at a certain latitude, only present in northern hemisphere

Deciduous vs. rain forest:

• Deciduous forests receive a moderate amount of annual rain/snowfall

• Rain forests receive the most precipitation out of all biomes

Temperate vs. tropical forest:

• Temperate forests grow in areas with moderate/average temperature and more seasonal temperature change

• Tropical forests grow in areas with hot average temperature, which doesn't change a lot over the year

Temperate deciduous forest:

• Moderate temperature

• Moderate precipitation

• Four seasons

• Mid latitudes

• Many species of plants

Temperate rain forest:

• Mild climate - somewhat warm all year

• Between coasts and mountains

• Maple, huckleberry, salmonberry

• Ferns and mosses

Tropical deciduous forest:

• Warm all year, rainfall is seasonal (wet and dry seasons)

• Trees drop leaves in dry seasons

• Occurs north and south of tropical rainforests

Tropical rain forest:

• Highest average temperate and average precipitation of any biome

• Tropical rain forests are up to twice as productive as temperate deciduous or temperate rain forest