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Biomes 1
Biomes
The objective of this set of lectures is
to familiarize you with the major
vegetation communities on Earth.
Biomes are somewhat arbitrary,
descriptive classifications, rather than
quantitative or objective categories.
The lines between biomes are often
vague.
Even so, this system is generally useful
for understanding the diversity, and
ecology, of the Earth’s vegetation.
Figure 23.1
Paleartic
Neartic
Oceania
Oceania
IndoMalay
Neotropic
Afrotropic
Australasia
Antartic
Tropical and subtropical moist broadleaf forests
Temperate grasslands, savannas, and shrublands
Tropical and subtropical dry broadleaf forests
Flooded grasslands and savannas
Tropical and subtropical coniferous forests
Montane grasslands and shrublands
Temperate broadleaf and mixed forests
Tundra
Temperate coniferous forests
Mediterranean forests, woodlands, and scrub
Boreal forests/taiga
Deserts and xeric shrublands
Tropical and subtropical grasslands, savannas,
and shrublands
Mangroves
Precipitation and temperature are the two
most important controls on biome
formation and stability.
The distribution of biomes across the
planet depends, largely, on those factors.
So… although we are going to give names
to some biomes- you can imagine that the
biome itself (and boundaries between
biomes) are variable across temperature
and precip gradients.
You need to understand this concept, and
have a general idea of how biomes abut,
and vary, across these gradients.
18.2 The distribution of biomes is determined by climate
General Classification Scheme
-Tundra
-Taiga/Boreal Forest
-Mixed Conifer Forest
-Deciduous Forest
-Savanna
-Shrublands
-Grasslands
-Desert
-Subtropical & Tropical
Tundra
•Climate
•Soils/Setting
•Dominant
Vegetation
•Characteristic
Animals
•Misc
Tundra
Tundra is the characteristic ecosystem in extremely cold climates. Plants
are mostly very low in stature. Animals often migratory. Soils are often
deep with frozen layers of organic matter. Permafrost is a characteristic
feature of the soils
Tundra
Soggy soils in summer, pock marked, low herbaceous vegetation.
Willow and alder are common/typical
Tundra
species in tundra areas. The particular
species found in tundra are “crawling”, and
extremely tolerant of cold. They are easily
overcome/outshaded by other species
(spruce and fir, in particular) if conditions
improve. Alder is a nitrogen fixing plant,
and has an interesting “successional”
relationship with other species. In the
winter, (and in extremely cold areas) tundra
can be expansive snow and ice fields.
http://www.youtube.com/watch?v=3XbJpevfNAs
Willow: Salix sp.
Alder: Alnus sp.
Caribou (Rangifer tarandus)
- herds, migratory
http://www.youtube.com/watch?v=5AYHvkR-0Qo
Polar bear (Ursus meritimus)
Weight: 1500 lbs
Height: ~9 feet
Polar bears hunt on ice sheets,
ripping seals from the ice like
sardines from a can.
Tundra
http://www.youtube.com/watch?v=DxVMnJXWvdM
18.2 The distribution of biomes is determined by climate
General Classification Scheme
-Tundra
-Taiga/Boreal Forest
-Mixed Conifer Forest
-Deciduous Forest
-Savanna
-Shrublands
-Grasslands
-Desert
-Subtropical & Tropical
Taiga
aka
Boreal Forest
aka
Spruce-Fir Forest
Taiga
aka
Boreal Forest
aka
Spruce-Fir Forest
Taiga/Boreal Forest
Boreal forest are circumpolar, taking up vast areas of
North America, Europe, Siberia, etc. They are areas
that are cold enough that deciduous species are at a
competitive disadvantage. What does that mean?
Soils are covered by a deep organic layer of fallen
needles, which decompose VERY slowly. These forests
are dominated by two genera of tree…
Taiga/Boreal Forest
Fir: Abies
Spruce: Picea
Moose (Alces alces)
Height: 6-7 feet
Weight: 1500 lbs
Grey Wolf (Canis lupus)
~100 lbs
This critter is badly misunderstood. There are very few records of wolves attacking
people. It only happens if the wolf has been (a) conditioned by idiots at parks who
feed wolves their Big Macs or (b) something odd is happening- the animal is
injured and starving, etc. It is 1 billion%* more likely that you will be bitten by
Aunt Edna’s “Pom Pom” than by a wolf, even if you lived in an area where wolves
were present.
* An approximation
Wolves are very important to
ecosystem structure. We will
focus on this later in the
semester.
By the way, wolves do not blow down pighouses, hide in
grammas cloths, and (despite photographic evidence- to the
right) they most likely did not nurse the founders of Rome, i.e.,
Romulus and Remus.
18.2 The distribution of biomes is determined by climate
General Classification Scheme
-Tundra
-Taiga/Boreal Forest
-Mixed Conifer Forest
-Deciduous Forest
-Savanna
-Shrublands
-Grasslands
-Desert
-Subtropical & Tropical
-Mixed Conifer Forest
Mountain gradients.
Rain shadows.
Climate.
Ponderosa pine (Pinus ponderosa).
Enormous size: 200 ft tall
Fire Ecology
Ecological importance
http://www.youtube.com/watch?v=mjdRgBAY278
Moist Conifer Forests of the Pacific Northwest
Coastal Redwood
(Sequoia sempervirens)
~1500 years
380 feet tall
Tallest living thing on Earth
Coastal Redwood
(Sequoia sempervirens)
Coastal Redwood
(Sequoia sempervirens)
Captures and imbibes
water from fog using
foliage. Translocates
this water down the
stem.
Not sure how….
Douglas-fir Pseudotsuga menziesii
390 feet (one was taller than redwood, but has since been lost)
~1500 years
Douglas-fir Pseudotsuga menziesii
Some of you have “real Christmas trees” every
year, and you probably buy the tree from
Lowes of something- if so, the tree has a good
possibility of being
Douglas fir (Pseudotsuga menziesii).
You might also have this tree planted in your
yard. Why would someone plant a tree from
Washington State in your yard? I have no clue
Douglas-fir is neither a Douglas, or a fir. It is
a tree that is relatively closely related to firs
which are the genus ________.
Douglas-fir is of enormous ecological and
economic importance. It is one of the most
widespread species in North America, with
varieties ranging basically across the whole
“conifer forest” area. It is extremely valuable
for lumber.
Cougar; mountain lion; catamount; panther = Puma concolor
- top predator. Avoids humans, but rare occasions of people being
stalked and killed.
-Length ~ 8 feet (including tail), Weight ~200lbs.
-Can run ~ 55 mph, vertical leap = 18ft
Issues of Conservation
18.2 The distribution of biomes is determined by climate
General Classification Scheme
-Tundra
-Taiga/Boreal Forest
-Mixed Conifer Forest
-Deciduous Forest
-Savanna
-Shrublands
-Grasslands
-Desert
-Subtropical & Tropical
Deciduous Forest
Deciduous Forest
Regions
American beech:
Fagus grandifolia
Oaks
Family: Fagaceae
Genus: Quercus
Maples
Family: Aceraceae
Genus: Acer
Specifically:
Red maple
Sugar maple
Live oak
Longleaf pine- a particular example of fire adaptation
Coyote (Canis latrans)
Length (not counting tail): 2.5 feet
Weight: 20-45 lbs
Attacks on humans extremely
rare- Aunt Ednas “pom pom”
much more likely to hurt you.
Might kill your cat, though. And
they do kill small mammals mice,
rabbits, raccoons- also snakes,
deer, and they eat carrion.
http://www.youtube.com/watch?v=97I-IDIKVSU&feature=related
White-tailed Deer
(Odocoileus virginianus)
Shoulder height: 40 inches or so
Weight: 100-300 lbs, largest known =
500 lbs
Populations of deer in eastern North
America are growing explosively.
Why? (a) Unchecked by predators,
and (b) living in environments that
are highly conducive to population
growth, they have become a major
problem.
http://www.insurancejournal.com/news/national/2012/10/24/267786.htm
blue jay
(Cyanocitta cristata )
Corvidae
Lin
northern cardinal
(Cardinalis cardinalis)
Cardinalidae
Lin
American robin
(Turdus migratorius)
Turdidae
Lin
Biomes 1