biomes

• Tropical regions: characterized by wet and dry seasons with year-round hot temperatures

• Dry season: brown and dormant

• Wet/rainy season: becomes green

• Many plants are drought deciduous

• Highly endangered in many places

• Few of them remain in their natural states

• Soil richer than rainforest

Tropical Seasonal Forests

• Humid regions in the tropics that support one of the most complex and biologically rich biomes

  • Cloud forests: at higher mountains

  • areas where rainfall > 200cm and warm to hot temperatures year round

Tropical Rainforests

• sparse tree cover

• Rainfall amount is not sufficient for forest growth

• Dry season: prone to fire

• Plants: deep rooted, adaptive (drought, heat and fire)

Tropical Savanna and Grassland

• low moisture levels (<30cm year)

• Wide daily and seasonal fluctuations of temperature

• Plants exhibit water conservation characteristics

  • Water storing stems

  • Thich epidermis

  • Salt tolerance

• Many plants bloom and set seed only after spring rains

• Animals have adaptations

  • Nocturnal

  • Able to conserve water

• Vulnerable

• Slow recovery when disturbances occur

• Overgrazing = major issue

Deserts

• Grasses and seasonal herbaceous flowering plants

• Few trees

• Large fluctuations in daily and seasonal temperatures

• Organic, thick, rich soils

• Majority converted to farmlands (tallgrass prairies)

• Overgrazing = threat

Temperate Grasslands

• warm, dry summers and cool, moist winters

• Evergreen shrubs, scrub oak, pines

• Fire - major issue

• High # of unique species (hotspot for biodiversity)

• Found in California, SW Australia, Central Chile, South Africa

Temperate Shrublands

• Support lush summer plant growth when water = plentiful

• Deciduous trees lose their leaves in winter: adaptation to freezing temps

Temperate Deciduous Forests

• Cool, rainy forest often completely hidden in fog

• Condensation in canopy (major form of precipitation in understory)

• Year-round mild temps

• Abundant rainfall

• Coniferous forests of pacific coast in California Giant Redwood 

• Abundant but often seasonal precipitation that supports growth of trees + understory vegetation

Temperate Rainforests

• Occur at high altitudes

Northern Coniferous Forest

• Broad band mixture of coniferous and deciduous trees between 50 and 60 N latitude

• Dominant species: Pines, hemlock, spruce, ceder and fir 

Taiga – North most edge of boreal forest

• Extreme cold and short summers

• Limit tree growth rate

• A tree with 10 cm diameter (4 in): May be over 200 years old Has moderate precipitation but often moist

Boreal Forests

• Treeless landscape occurs at high latitudes + mountaintops

• Growing season = 2-3 months

• Frost any month of year

• No trees

• Water frozen and unavailable most of year

• Low biodiversity compared to other biomes

Tundra