2. 2.4 Biomes zonation & succession
• Biomes are collections of ecosystems sharing similar climatic conditions that
can be grouped into five major classes: aquatic, forest, grassland, desert
and tundra. Each of these classes has characteristic limiting factors,
productivity and biodiversity.
• Insolation, precipitation and temperature are the main factors governing the
distribution of biomes.
• The tricellular model of atmospheric circulation explains the distribution of
precipitation and temperature and how they influence structure and relative
productivity of different terrestrial biomes.
• Climate change is altering the distribution of biomes and causing biome
shifts.
4. What is a biome?
• World climate is variable
– Differences in temperature and precipitation
– Different climates Different communities
• Biomes = Regions of the earth characterized by
specific climates and community types
• Remember they cross national boundaries
• Real biomes do not have sharply defined
boundaries. Ecotones = Transitional zones
• Biomes not uniform, instead a mosiac of
patches
– Vary in microclimate, soil types, disturbances
10. For each Biome you should comment in
the distribution, climate (read
climatograms), structure, relative
productivity and limiting factors
11. Mountain
Ice and snow
Altitude
Tundra (herbs,
lichens,
mosses)
Coniferous
Forest
Tropical
Forest
Deciduous
Forest
Tropical
Forest
Deciduous
Forest
Coniferous
Forest
Tundra (herbs,
lichens, mosses)
Polar ice
and snow
Latitude
Main Biome Effects
Climate and vegetation vary in a predictable
fashion with changes in Altitude and Latitude
12. Vegetation changes
• Plants in cold regions have traits to limit heat
& water loss
– Winter dormancy (drop leaves), smaller size,
evergreens have needles
• Plants in dry areas must lose heat and
conserve water
– No leaves, water storage, nocturnal activity
• Plants in rainforests must get light and
remove water
– Broad leaves, drip tips, radiate heat
14. Deserts
1. Climate
• Precipitation < 25 cm / yr – scattered unevenly through
year Arid
• May be Tropical, Temperate and Cold types – always
extremes
• High to moderate insolation
2. Distribution
• 30% of earth surface between 30 degrees north and
south of the equator – Major ones Saraha (Africa), Gobi
(Asia), Mojave (N. america)
3. Structure
• Simple – very little vegetation
• Most complex is temperate desert which has largest cacti
4. Relative Productivity
• Low – limited by water availability
16. Desert Types
• Tropical Deserts
• High temp. year round
• Little rain, only 1-2
months
• Driest places on earth
• Few plants
• Hard windblown
surface: sand & rock
• Middle East areas
Tropical desert
(Saudi Arabia)
17. Desert Types
• Temperate Deserts
• Day temp. high in
summer, low in winter
• More precipitation
• Sparse vegetation –
suculents, cacti,
animals
• Southern CA (Mojave)
Temperate desert
(Reno, Nevada)
18. Desert Types
• Cold deserts
• Winters cold
• Summers warm to hot
• Precipitation low
• Gobi desert, China
Polar desert
(northwest China)
19. Plant Adaptations
Every drop of water counts
1. Wax coated leaves
limit transpiration
2. Deep roots tap
underground water
3. Wide spread shallow
roots gather falling
water
4. Drop leaves &
dormancy in heat & dry
periods
5. Store biomass in
seeds
20. Animal Adaptations
• Hiding in cool areas
during day
• Thick skin
• Dry feces,
concentrated urine
• Water from dew & food
• Dormancy in heat &
drought
21. Producer
to primary
consumer
Primary
to secondary
consumer
Secondary to
higher-level
consumer
All producers and
consumers to
decomposers
Fungi
Gambel's
quail
Red-tailed hawk
Collared
lizard
Jack
rabbit
Yucca
Kangaroo rat
Kangaroo rat
Agave
Agave
Roadrunner
Roadrunner
Diamondback rattlesnake
Diamondback rattlesnake
Darkling
beetle
Darkling
beetle
Bacteria
Bacteria
Prickly
pear
cactus
Prickly
pear
cactus
22. Human Impacts on Deserts
Large desert cities
Soil destruction by vehicles
and urban development
Soil salinization from irrigation
Depletion of underground
water supplies
Land disturbance and pollution
from mineral extraction
Storage of toxic and radioactive
Wastes
Large arrays of solar cells and
solar collectors used to produce
electricity
23. Temperate Grasslands
1. Climate
• Precipitation 25-45 cm / yr – enough to grow grass, erratic Semiarid
• fire, drought, animals prevent tree growth
• May be Tropical, Temperate
• Moderate insolation
2. Distribution
• 9% of earth surface Temperate Latitudes – Major onesNA tall grass
prairie, steppes, pampas, veldt
• Grasslands overall up to 40% of earth’s surface
3. Structure
• Simple – grasses and herbaceous plants
4. Relative Productivity
• Medium to high – high turnover of grasses, rich soils
24. Polar Tundra Alpine Tundra Temperate Grassland Tropical Savanna
World Distribution of Grasslands
26. Producer
to primary
consumer
Primary
to secondary
consumer
Secondary to
higher-level
consumer
All producers and
consumers to
decomposers
Fungi
Bacteria
Golden eagle
Prairie
dog
Blue stem
grass
Blue stem
grass
Coyote
Coyote
Grasshopper
Grasshopper
Grasshopper
sparrow
Grasshopper
sparrow
Pronghorn antelope
Pronghorn antelope
Prairie
coneflower
Prairie
coneflower
27.
28. Grassland Types
• Tropical Grasslands
• Savannas
• High average temp
• Moderate rainfall
• Prolonged drought
• Herds of herbivores
– Grazing & Browsing
• Africa, SA, Australia
• Migrations in dry
season Tropical grassland (savanna)
(Harare, Zimbabwe)
29. Herbivore coexistence
• Minimize competition by resource
partitioning
• African animals differ by region & niche
1. Giraffes eat leaves from tree tops
2. Elephants eat leaves and branches further
down
3. Gazelles & Wildebeasts eat short grasses
4. Zebras eat longer grass & stems
31. Dry Thorn Scrub Riverine Forest
Dik-dik East African
eland
Blue duiker Greater
kudu
Bushbuck
Black rhino
Giraffe
African elephant
Gerenuk
32.
33. Human effects on Grasslands
Conversion of savanna and temperate
grassland to cropland
Release of CO2 to atmosphere from
burning and conversion of grassland
to cropland
Overgrazing of tropical and temperate
grasslands by livestock
Damage to fragile arctic tundra
by oil production, air and water pollution,
and vehicles
34. Tundra
1. Climate
• Precipitation < 15 cm / yr – mostly snow & summer rain
Arid
• Bitter cold -57 – 50 °C - permafrost
• low insolation gives short growing season
2. Distribution
• 60 – 75 °N latitude – northern North America, Asia,
Greenland
• About 20% of the earth’s surface
3. Structure
• Simple – low spongy mat of vegetation, lichens, mosses
• Even trees are less than knee high
4. Relative Productivity
• Low – limited by temperature and insolation
37. Polar grassland (arctic tundra)
(Fort Yukon, Alaska)
Tundra
• Treeless spongy mat of
low growing plants
• Common breeding area
b/c predators visible
• Organisms migratory
• Cold & Windy & Dark
• Ice & snow cover
• Low precipitation but
poor drainage b/c
Permafrost
38. Producer to
primary
consumer
Primary to
secondary
consumer
Secondary to
higher-level
consumer
All consumers
and producers
to decomposers
Lemming
Arctic
fox
Horned lark
Mosquito
Grizzly bear
Long-tailed jaeger
Caribou
Willow ptarmigan
Willow ptarmigan
Snowy owl
Snowy owl
Dwarf willow
Dwarf willow
Mountain cranberry
Mountain cranberry
Moss campion
Moss campion
39. Forest Types
• Undisturbed areas with moderate to high
rainfall
• Dominated by various species of trees and
other vegetation
• 3 main types of forest – Tropical,
Temperate, Boreal
40. World Distribution of Forests
Temperate coniferous forests Temperate deciduous forests Tropical rain forests
41. Tropical Rainforest
1. Climate
• Precipitation over 150 cm / yr – Wet – still rainy and dry seasons
• Warm humid year round climate 80 °F
• high insolation gives long growing season
2. Distribution
• 23.5 °N to 23.5 °S latitude – Tropic of Capricorn to Cancer
• About 2% of the earth’s surface
• Three chunks – S. & C. America, C. Africa, SE Asia
3. Structure
• Complex – stratified layers
• High diversity - 50-80% of terrestrial species
4. Relative Productivity
• Highest in terrestrial system – unlimited by temperature and insolation
42. Tropical rain forest
(Manaus, Brazil)
Tropical
Rainforest
• Tropical Rainforest
• Broadleaved evergreen trees
• High biological diversity,
Specialized niches,
• Much of animal life found in
canopy layer
• Stratification of life in different
tree layers increases niche
partitioning
• Paradox high diversity but
very poor soils
• Rapid recycling of nutrients
• Little nutrients stay in soil
most taken back into plants
• Dense forest limits wind
animal pollinators
44. Producer
to primary
consumer
Primary
to secondary
consumer
Secondary to
higher-level
consumer
All producers and
consumers to
decomposers
Fungi
Bacteria
Bromeliad
Ants
Tree frog
Green tree snake
Katydid
Climbing
monstera palm
Squirrel
monkeys
Blue and
gold macaw
Harpy
eagle
Ocelot
Slaty-tailed
trogon
Slaty-tailed
trogon
45. Diverse forests cleared
Replaced with monospecific
stands – tree plantations
Songbird species often
spend time in these areas
Top predators hunted out
and displaced
Fragmentation of habitats
46. Temperate deciduous forest
(Nashville, Tennessee)
Forests
• Temperate Forests
• Significant seasonal
changes
• Abundant precipitation
throughout year
• Dominated by a few
broadleaved deciduous
trees
• Simple structure
• Thick layer of leaf litter
• Once diverse, now
predators gone
47. Producer
to primary
consumer
Primary
to secondary
consumer
Secondary to
higher-level
consumer
All producers and
consumers to
decomposers
Bacteria
Fungi
Wood frog
Racer
Shagbark hickory
White-tailed
deer
White-footed
mouse
White oak
Gray
squirrel
Hairy
woodpecker
Broad-winged
hawk
Long-tailed
weasel
Long-tailed
weasel
May beetle
May beetle
Mountain
winterberry
Mountain
winterberry
Metallic
wood-boring
beetle and
Metallic wood-
boring beetle
and larvae
48. Polar evergreen coniferous forest
(boreal forest, taiga)
(Moscow, Russia)
Forests
• Boreal Forests (Tiaga)
• Just below tundra
• Dominated by coniferous
tree species
– Withstand cold, rapid
growth in summer
• Low temperature
– Low decomposition, high
soil acidity
• In summer soil is
waterlogged = muskegs
49. Producer
to primary
consumer
Primary
to secondary
consumer
Secondary to
higher-level
consumer
All producers and
consumers to
decomposers
Bacteria Bunchberry
Starflower
Fungi
Snowshoe
hare
Bebb
willow
Moose
Wolf
Balsam fir
Blue jay Great
horned
owl
Great
horned
owl
White
spruce
White
spruce
Pine sawyer
beetle and larvae
Pine sawyer
beetle and larvae
Marten
Marten
50. Clearing and degradation of tropical
forests for agriculture, livestock grazing,
and timber harvesting
Clearing of temperate deciduous
forests in Europe, Asia, and
North America for timber, agriculture,
and urban development
Clearing of evergreen coniferous
forests in North America, Finland,
Sweden, Canada, Siberia,
and Russia
Conversion of diverse forests to less
biodiverse tree plantations
Human Effects on Forests
