Biomes Flashcards
(18 cards)
What is a biome?
A large, relatively distinct terrestrial region
Similar climate, soils, plants and animals regardless of global location
Vary in geographic extent
Whittaker (1975)
Boundaries between biomes are broad and often distinct
Temperature and precipitation are the main factors of distinction
Other factors like top0graphy (geographical shape of the land), oils and exposure to disturbances like fire
Consumer controls
Herbivores, natural and livestock
Fire (abiotic)
Human, forest clearance, crop lands and settlements
Consumer controls reduce NPP and biomass giving much less than the predited
Tundra
Permafrost
Short growing seasons
Soil is nutrient poor, low organic matter content
Dominant veg is sedges, grasses
Low species richness and low PP
Animals are often migratory
Plants have small leaves, low growing, dark coloured and the flowers track the sun
Taiga/boreal forest
Coniferous forest biome
Very cold winters and short cool summers
North of Eurasia and North America
Soil is nutrient poor, acidic and slow decomposition due to cold temps
Low PP and species richness
Vegetation is drought-resistant evergreens like white spruce
Animals are migratory or hibernate
Plants often have needles to reduce water loss, shed snow, drooping branches and cold tolerant
Temperate rain forest
Coniferous biome
Cool weather, dense fog, precipitation mainly in winter
Mild winters
Broadleaved temperate rainforest
Soil is nutrient poor, lots of organic matter, slow decomposition
Large evergreen trees, old-forest growth, seedlings, saplings
High species richness
Moderate PP
Animals are cool-climate adapted
Adaption to low light under canopy and lack of drought tolerance
Temperate deciduous forest
Seasonal
Soil is rich in organic matter and higher in nutrients due to warmth
Deciduous - oak, maple, beech
Canopy layers
Potential for high species richness
Much is secondary after timber extraction and has regenerated after farming
Moderate primary productivity
Animals include bears, wolves, small animals
Plants are often early-flowering ground flora with shade tolerance
Temperate grassland
Too little precipitation to support trees
Not grassland without consumer control (90% lost to farming)
Seasonal with hot summers and cold winters
Soil is a thick organic rich horizon
Herbaceous (non-woody) plants
High species richness
Animals have the ability to eat and digest grasses, once supported large herbivore megafauna now only bison in places
Smaller animals like prairie dogs present
Plants are adapted to tolerate grazing, fire, drought and shrubs with thick bark
Mediterranean
Mid moist winters and hot dry summers
Human modified
Shrubland, scrub, open woodland
Mostly coastal
Soil is often nutrient poor and thin
Dense evergreen shrubs, herbaceous plants
High species richness
Low primary productivity as limited by precipitation
Animals are nocturnal, adapted to little water, fox, puma, lizard, tortoise etc
Plants are adapted to tolerate drought, grazing, fire and defensive chemicals
Desert
Large diurnal/seasonal temperature swings
Conditions are variable by location
Soil is nutrient poor and high in salts
Vegetation is sparse, low to moderate species richness, shrubs, small trees, short-lived herbaceous plants
High in endemic and threatened species
Low primary productivity
Animals are small and typically nocturnal
Plants are succulent with reduced leaves, defended, deep roots, hairy or waxy, ephemeral
Savanna
Tropical grassland biome with scattered trees
Constant warmth
Soil is nutrient poor due to leaching
Low to moderate primary productivity
Animals have diets adapted to grazing and browsing (ungulates) also large predators like lions and hyenas
Plants are adapted to fire, grazing and drought
Trees cover up to 80%
High species richness and intact megafauna
Tropical rainforest
Constant warmth and moisture throughout the year
Soil is highly weathered, ancient and nutrient poor
Forest, 3 canopy layers, very high species richness
High primary productivity
Most species rich insect, reptile and amphibian communities
Plants are shade tolerant, compete for light, buttress roots and drip trips
Lake and pond layers
Littoral zone - shallow water and close to shore
Limnetic zone - open water beyond littoral zone
Profundal zone - beneath limnetic
Aquatic layers
Photic zone - sufficient light for photosynthesis
Aphotic zone - insufficient light for photosynthesis
Oligotrophic - deep, nutrient poor, water is very clear
Eutrophic - shallower, nutrient rich, murky
Mesotrophic is inbetween these
Marine ecosystem life zones
Intertidal - area between high and low tides, sandy or rocky, large changes in temp, oxygen and salinity
Benthic eg seagrass beds, kelp forests, coral reefs
Pelagic - open ocean water
What defines the world’s climate?
Temperature
Precipitation
Humidity
Wind
Differential heating of the planet by sunlight and radiant energy
Global atmospheric circulation
Marshes and swamps
Covered by shallow fresh water for the most part of the year
Soil is waterlogged an anaerobic for periods
Water tolerant plants
Offer flood protection, bioremediation and carbon storage
Estuaries
Where fresh and salt water mix
Highly variable environment - temp, salinity and light penetration
Highly productive, nutrients from land, tidal action promotes circulation, high level of light in shallow water
