BIOMES

Biomes and climate associations

A. Forest Biomes

1. tropical rainforests: light and nutrient competition key: (found in tropical wet climate having no dry season or a short dry season)

3 or 4 "tiers"

the "jungle" myth and the dark floor

slash and burn agriculture

found on trade wind coasts, areas dominated by ITCZ

the ecotone: zone of transition between biomes

2. tropical seasonal forests: caused by a significant dry season (which can be cool if at elevation), often located where ITCZ movement creates a wet season

3. midlatitude (temperate) forests: wet summers, typically in interior of continents up to or near east coasts

-lose leaves due to cold, inability to photosynthesize, self-protection

-ground layer veg. richest in spring…why?

-pines (coniferous) are found in drier soil areas and often burned areas (pine bark more resistant), thus pine not a "climax species"

4. Mediterranean forest and scrub: pines and oaks (woodlands) (CA)

mild, rainy winter, hot dry summer (mid latitude west coasts, summers dominated by high pressure)

5. boreal forest (COLD)

-coniferous trees: needles begin photosynthesis rapidly

transpiration low from small, waxy needles (soil may be frozen)

6. Temperate rainforest (eg coastal OR - AK) conifers dominate, mild winters, highly productive, greatest biomass of any forest

B. Grassland Biomes

1. Savanna (tropical grasslands) rainy season in high sun season, generally found just poleward of tropical forests, fire can increase productivity

2. midlatitude grassland

world’s most productive farmland soils

C. Tundra and Mountain Biomes “read up, please”

D Desert Biomes - xerophytes:

adaptations to aridity:

1. deep roots or roots with great areal coverage

2. waxy and/or small leaves

3. bark capable of photosynthesis

4. water storage

5. short annual life cycle

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(optional) Ocean Environments

-warm water continental shelves: great species diversity, coral reefs

-coastal upwelling (near west coasts): very productive (nutrient sources)

open ocean: less productive…why?