Transcript TerrestrialBiomes

Terrestrial Biomes
The largest land community which is convenient to recognize is called a
biome. Biomes are characterized by their climax vegetation which is the key
to their identification.
Major terrestrial biomes include: Tundra, Boreal forest (Taiga, or Northern
Coniferous Forest), Temperate Deciduous Forest, Broad-Leafed Evergreen
Subtropical Forest, Temperate Grassland, Tropical Savanna, Tropical Rain
Forest, Chaparral, and the Desert.
The Desert Biome
What is a Desert?
Deserts in the Southwestern United States are areas of extreme heat and
dryness. They occur in regions with less than 10” of rainfall per year, or
in regions of greater rainfall if it is unevenly distributed. In some deserts,
the amount of evaporation is greater than the amount of rainfall. Typically,
desert moisture occurs in brief intervals and is unpredictable from year
to year. About one-third of the earth's land mass is arid to semiarid
(either desert or semi-desert).
There are four major types of deserts:
Hot and Dry
The seasons are generally warm throughout the year and very hot in the
summer. The winters usually bring little rainfall. Temperatures exhibit daily
extremes because the atmosphere contains little humidity to block the
Sun’s rays. Evaporation rates regularly exceed rainfall rates. Sometimes
rain starts falling and evaporates before reaching the ground. Examples
are the Sonoran, Mojave and Great Basin deserts of the Southwestern
U.S. as well as the Chihuahuan Desert in West Texas and Mexico
Semiarid Deserts
The major deserts of this type include the sagebrush of Utah, Montana
and parts of the Great Basin. They are still hot and dry, but not so much
as the above.
Scarcity of rainfall may be caused by:
1. A rain shadow of a mountain (Mojave, Sonoran and Great Basin
deserts )
2. Trade wind belts (Sahara desert, world’s largest desert.)
3. Warm land alongside of cold water (coastal deserts)
Most deserts receive some rain and have at least a sparse cover of
vegetation unless adaphic factors (wind) are particularly unfavorable.
Three life forms of plants are adapted to desert conditions:
1. Annuals - avoid drought by
growing only when there is
adequate moisture (survive as
seeds)
Bear Poppy
Desert Sand Verbena
Birdcage Evening Primrose
Desert Star
2. Succulents - store water (cacti)
Almost the entire stem of a cactus is
parenchymatous water storage tissue, thus 80-90
percent of a cactus is water. A cactus plant will
lose less than one-thousandth as much water
as a mesophytic plant of the same weight. Cacti
of arid regions can withstand considerable water
loss. For example, a mesophytic plant would wilt or
possibly even die when it loses 10-20 percent of its
water. Cacti can withstand a water loss of 60
percent.
Cactus stomates are open at night and store carbon dioxide until the
daytime so it can photosynthesize. The storing of carbon dioxide from
night to day is a special feature of succulent plants called "succulent
metabolism” or technically as CAM metabolism.
3. Desert shrubs
Desert shrubs have extensive roots and small, thick waxy leaves to
reduce transpiration. The leaves may be shed in prolonged dry
seasons. Bark may have chlorophyll.
The extensive root systems are
adapted to absorb water very quickly.
Color, hairs and spines, salt glands,
shape, size, and growth form are some of
the ways that plants deal with excess
thermal energy. The color of a plant
affects the amount of solar radiation
absorbed by leaves. Leaves that are
shiny, light green or gray/silver in color
have a high reflectivity and absorb less
heat. Many desert shrubs use color to
stay cool.
The Great Basin Desert, a rain shadow
desert, is the largest U. S. desert. It
covers an arid expanse of about 190,000
square miles and is bordered by the
Sierra Nevada Range on the west and
the Rocky Mountains on the east, the
Columbia Plateau to the north and the
Mojave and Sonoran deserts to the
south. Sagebrush is the most common
plant in the Great basin
Great Basin Desert
Sagebrush
Desert animals are also adapted
Reptiles and insects are somewhat “pre-adapted” because of their
relatively impervious integument and dry excretions.
As a group, mammals are not well adapted because they excrete urea that
requires water for excretion, and most use water for temperature regulation.
However many mammals managed to adapt to the dry conditions.
Kangaroo rats and pocket gophers do not have to
drink water and can live on a diet of dry seeds.
They conserve metabolic water by excreting a
concentrated urine and do not use water for
temperature regulation. They remain in their burrows
during the day.
Other adaptations include means of dissipating body heat
other than evaporative cooling such as subsurface
blood flow (large ears of hare with rich blood supply).
Chaparral Biomes
Chaparral Biomes occur in regions with abundant winter rainfall but with dry
summers. The climax vegetation consists of trees or shrubs with hard
thick evergreen leaves.
Chaparral communities are extensive in California and Mexico. A large
number of plant species may serve as dominants depending on the region
and local conditions. Fire is an important factor that tends to perpetuate
shrub dominance.
In California, 5-6 million acres of slopes and
canyons are covered with chaparral shrubs
which form dense thickets. The rainy
season usually extends from November to
May. Mule deer and many birds inhabit the
chaparral during this period, then move to
higher altitudes during the hot summer.
Animals are all mainly grassland and desert types adapted to hot, dry
weather. A few examples: coyotes, jack rabbits, mule deer, lizards,
snakes, chipmunks, wood rats, bush rabbits.
Temperate Grassland Biome
Grasslands occur where rainfall is too low to support a forest but higher
than that of a desert (10 - 30” per Yr). However, grasslands also occur in
areas of forest climate when edaphic factors (fire) favor grass. Temperate
grasslands usually occur in the interior of continents.
They are important economically because they
provide natural pastures for grazing, and
conversion of moist grasslands into cultured
grain crops involves very little basic change in
ecosystem structure.
Grasslands in drier climates such as found in
the Western Great Plains consist of shorter
grasses than those in the Eastern Great
Plains (tall grasslands).
Great Plains, mixed tall and short grassland
Most grassland mammals are either running or burrowing types.
Aggregation into colonies or herds is characteristic. Burrowers include
ground squirrels, gophers, and prairie dogs. Burrowing predators like
burrowing owls and the black footed ferret (an endangered species) prey
on the rodents. Typical birds are prairie chickens, meadow larks and
hawks.
The Blackland Prairie

totals about 4.3 million hectares or roughly
six percent of the total land area of Texas
and is a region slightly larger than the state
of Maryland. It coincides almost exactly
with a belt of outcropping Upper
Cretaceous marine limestone and shales that
upon weathering forms the characteristic
black, calcareous, alkaline, heavy clay,
"black waxy" soil (Diggs et al. 1999).
The Blackland Prairie
Conditions in presettlement Blackland
Prairies were strikingly different from those
found today and the most striking difference
was the presence of vast expanses of tall
grass prairie (Diggs et al. 1999).
 Fire was an important factor in
maintenance of the original prairie
vegetation and had a major impact on
community structure (Diggs et al. 1999).

The Blackland Prairie

Tall grass prairie fires would have been
stopped only by the lack of dry fuel or by a
major waterway. Even waterway vegetation
was susceptible during dry years and trees
were rare even along some stream banks
(Diggs et al. 1999) (For other citations, see
the literature cited section from Diggs et al.
1999 at:
http://artemis.austincollege.edu/acad/bio/gdi
ggs/literature.html
The Blackland Prairie

early (back to the 1830s) surveyor records
of mesquite as the most common tree in
presettlement upland prairies in Navarro
County suggest ". . .the legendary spread of
mesquite into North Texas by longhorn
cattle may be an errant concept" (Jurney
1987). Roemer's (1849) mention of
"extensive prairies covered with mesquite
trees" also points to mesquite as a natural
component of the vegetation.
The Blackland Prairie
mesquite has increased in many areas and
the observations mentioned above are not so
early as to preclude mesquite having
already being spread to some extent by land
use changes (Diggs et al. 1999).
 While some question the degree to which
mesquite was spread by longhorns, animals
have had profound impacts on the
vegetation since long before settlement
(Diggs et al. 1999).

The Blackland Prairie
These range from dust bathing and
mating displays by bison to damming and
herbivory by beaver to the more subtle
roles of pollination and seed dispersal.
 Present animal life is different and some
species reduced compared with earlier
times. In addition to present-day species
such as the white-tailed deer, coyote, fox,
and bobcat, a number of other large or
species occurred (Diggs et al. 1999).

The Blackland Prairie
Brooke (1848) writing of Grayson County,
said black bears were quite common ("I. .
have never tasted any meat I like better.") as
were deer; mountain lions and wolves.
 Another predator, the ocelot, is thought to
have ranged as far north as the Red River
(Hall & Kelson 1959). Strecker (1924), for
example, reported that ocelot occurred in
the bottoms of the Brazos River near Waco

The Blackland Prairie

Even jaguar are believed to have ranged
north to the Red River; the last jaguar
record from North Central Texas was a
large male killed in Mills County
(Lampasas Cut Plain) in 1903 (Bailey
1905). The collared peccary or javelina, was
also originally present in the southern
portion of the area, north to at least the
Brazos River valley in McLennan County
near Waco (Davis & Schmidly 1994).
The Blackland Prairie

Other large mammals that previously
occurred in appropriate habitats of the
Blackland Prairie as well as throughout the
rest of North Central Texas include river
otter, ringtail, and badger (Davis &
Schmidly 1994). Pronghorn antelope were
also native. Smythe (1852) saw a herd on
the E edge of the Blacklands while Roemer
(1849) saw them where the Blackland
Prairie and Lampasas Cut Plain intersect.
The Blackland Prairie
While not native, wild horses, introduced
from the Spanish, were by the early 1800s
extremely common in Texas and were
probably having a significant impact on the
vegetation. (Diggs et al. 1999).
 Brooke (1848), writing about early Grayson
County, mentioned both turkeys and prairie
chickens.

The Blackland Prairie

The extinct passenger pigeon is also well
documented for the Blackland Prairie and
the ivory-billed woodpecker species, was
also present in bottomland forests in the
Blacklands. Another extinct species, the
Carolina parakeet was probably present in
the bottomland forests of the Blackland
Prairie ((Diggs et al. 1999).
The Blackland Prairie
Alligators were abundant in places, with
Kendall (1845) reporting them along the
San Gabriel in the southern Blackland
Prairie. He also stated that, "The stream
abounds with trout, perch, and catfish, as do
nearly all the watercourses in this section of
Texas."
 Alligators occurred in appropriate habitats
throughout most of the Blackland Prairie
(Brown 1950; Hibbard 1960; Dixon 1987).

The Blackland Prairie
According to Gould and Shaw (1983), the
Blackland Prairie (and in fact all of North
Central Texas) is part of the True Prairie
grassland association, extending from Texas
to southern Manitoba.
 Two of the common dominants of the
prairie included little bluestem and Indian
grass along with numerous other grass
species and forbs.

The Blackland Prairie

Although prairie dominated, some wooded
areas were present at the time of settlement.
Examples include bottomland forests and
wooded ravines along the larger
waterways, mottes in protected areas or
on certain soils, scarp woodlands at
contact zones with the Edwards Plateau
and Lampasas Cut Plain, and upland oak
woodlands similar to the Cross Timbers
(Gehlbach 1988; Nixon et al. 1990;
Diamond & Smeins 1993).
The Blackland Prairie
Oaks, elms, ash, sugarberry were
common trees with many kinds of shrubs.
 With the exception of preserves, small
remnants, or native hay meadows, almost
nothing remains of the original Blackland
Prairie communities. According to Diamond
et al. (1987), all of the tall grass
community types are ". . .endangered or
threatened, primarily due to conversion of
these types to row crops."

The Blackland Prairie

Recurrent fire and grazing by bison were
natural processes that maintained the
Blackland ecosystem; the removal of these
processes is a disturbance that causes
changes in the vegetation (Smeins 1984;
Smeins & Diamond 1986; Diamond &
Smeins 1993).
The Blackland Prairie

Periodic disturbance is essential for the
maintenance of prairie. However, even
native hay meadows, which are routinely
disturbed, are often very different from
the original due to substitution of mowing
and herbicide use in place of fire and
grazing. The results include a reduction in
broad-leaved plants and an increased
abundance of grasses (Diamond & Smeins
1993).
The Blackland Prairie

While grazing was a natural component of
the Blacklands and many other Texas
ecosystems, overstocking and thus
overgrazing by domesticated animals has
also caused a dramatic decline and even
near elimination of numerous plants from
many areas (Cory 1949). The cumulative
effect of all these human-induced changes is
that the Blackland Prairie communities have
been largely destroyed (Diggs et al. 1999).
The Blackland Prairie

Large areas that were once tall grass
prairie are now covered by crops or other
introduced and now naturalized species
such as King Ranch bluestem, Bermuda
grass, and Johnson grass. Roadsides and
pastures are particularly obvious examples;
in many cases hardly any native grasses can
be found. In these areas there has also been
an accompanying dramatic reduction in
native forb diversity (Diggs et al. 1999).
CROSS TIMBERS AND
PRAIRIES
Vegetationally, it is quite diverse and
includes the East and West Cross Timbers,
the Fort Worth Prairie, and the Lampasas
Cut Plain.
 Cross Timbers stretch from Texas north
through Oklahoma to Kansas (Marriott
1943; Dyksterhuis 1948; Kuchler 1974),
and are found in Texas from the Red River
south for about 150 miles.

CROSS TIMBERS AND
PRAIRIES

They are actually two discrete belts of
forest divided by the enclosed Grand
Prairie (Dyksterhuis 1948). Surrounded by
prairie on both sides (Blackland Prairie to
the east, Rolling Plains to the west), they
represent a final disjunct western extension
of eastern deciduous forest before the
vegetation changes into the vast expanse of
central U.S. grasslands known as the Great
Plains (Diggs et al. 1999).
CROSS TIMBERS AND
PRAIRIES

The two separate belts are the East Cross
Timbers and the West Cross Timbers,
sometimes referred to as the Lower Cross
Timbers and Upper Cross Timbers
respectively (Diggs et al. 1999). According
to Hill (1887), these names developed
because the West or Upper Cross Timbers
is at a greater altitude and in a more
upstream position relative to the flow of
rivers in the area.
CROSS TIMBERS AND
PRAIRIES

The East Cross Timbers is a narrow strip
(roughly along the 97th meridian) extending
from the Red River, in eastern Cooke and
western Grayson counties, south to near
Waco where it merges with the riverine
forests of the Brazos River (Hayward &
Yelderman 1991).
CROSS TIMBERS AND
PRAIRIES

The somewhat wider West Cross Timbers
stretches west from the Grand Prairie,
which includes the Ft. Worth Prairie and
Lampasas Cut Plain to the beginning of the
Rolling Plains and includes the rather
rugged Palo Pinto Country (in Eastland,
Jack, Palo Pinto, Stephens, and Young
counties) (Diggs et al. 1999).
CROSS TIMBERS AND
PRAIRIES

The Fort Worth Prairie portion of the
Grand Prairie extends as a continuous body
of open grasslands, from near the Red River
in the north, south to where it ends in the
wooded area along the Brazos River near
the Johnson County-Hill County line
(Dyksterhuis 1946).
CROSS TIMBERS AND
PRAIRIES

The Lampasas Cut Plain, the largest
portion of the Grand Prairie, is highly
dissected butte and mesa country with
extensive lowlands, and can in some ways
be considered a northernextension of the
Texas Hill Country and Edwards Plateau. It
has strong geologic and floristic links with
the Edwards Plateau and is considered a
part of the Edwards Plateau by some
authorities (e.g., Riskind & Diamond 1988).
CROSS TIMBERS AND
PRAIRIES

The Cross Timbers vegetation at the time of
contact by Europeans thus probably
exhibited considerable variation (Diggs et
al. 1999). Parker (1856) described the area
just west of the East Cross Timbers but east
of what he referred to as the Grand Prairie
(east of Gainesville in Cooke County) as
follows:

. . . soon leaving the timber, we entered
upon a broken country, consisting of ridges
of sand and limestone, interspersed with
small prairies and small strips of timber,
principally black jack, until we emerged
upon and crossed Elm Fork of the Trinity,
where, on account of the intense heat,
Captain Marcy determined to halt and
encamp, thereafter, intending to march by
moonlight, until we reached the Grand
Prairie (Parker 1856) .

The variable nature of the Cross Timbers is
also reflected in the following description
from Kendall (1845): The growth of timber
is principally small, gnarled, post oaks and
black jacks, and in many places the traveler
will find an almost impenetrable
undergrowth of brier and other thorny
bushes. Here and there he will also find a
small valley where timber is large and the
land rich and fertile, and occasionally a
small prairie intervenes; but the general face
of the country is broken and hilly, and the
soil thin.
CROSS TIMBERS AND
PRAIRIES
The animal life of the Cross Timbers was
probably similar to that described earlier
for the Blackland Prairie.
 The East and West cross timbers, have their
woody overstory consisting primarily of
post oak and blackjack oak (Diggs et al.
1999).

CROSS TIMBERS AND
PRAIRIES

Based on these accounts and on an
extensive vegetational study of the West
Cross Timbers by Dyksterhuis (1948),
presettlement vegetation can probably best
be described as a savannah with an oak
overstory, but dominated little bluestem,
with two other grasses, big bluestem, and
Indian grass, as lesser dominants.
Little bluestem
CROSS TIMBERS AND
PRAIRIES

At present, in many Cross Timbers
localities, younger trees are often branched
to the ground, making movement through
the vegetation extremely difficult and
denying habitat for the originally dominant
grasses; dense cedar brakes (Diggs et al.
1999), mesquite and prickly pear are
problematic, likely due to fire
suppression and overgrazing.
CROSS TIMBERS AND
PRAIRIES

One of the most striking features of the
Cross Timbers is that this vegetational area
contains significant remnants of virgin
forests (Stahle & Hehr 1984; Stahle et al.
1985). According to Stahle (1996a), “. . .
literally thousands of ancient post oakblackjack oak forests still enhance the
landscapes and biodiversity of. . . the Cross
Timbers along the eastern margin of the
southern Great Plains. . . .”
CROSS TIMBERS AND
PRAIRIES

As as result, this is one of the largest
relatively unaltered forest vegetation
types in the eastern United States (Stahle
& Hehr 1984). The small stature and often
poor growth form of post and blackjack
oaks made these species commercially
unattractive and therefore less subject to
systematic logging than other more
productive forest types (Diggs et al. 1999).
CROSS TIMBERS AND
PRAIRIES
Riparian regions in both the Cross
Timbers and Grand Prairie regions have
high biodiversity
 Major rivers include the Red, Trinity,
Brazos, and the Colorado
Handout on the Colorado River and the
Lampasas Cut Plain

Tropical Savanna Biome (Tropical Grasslands)
Tropical savannas are found in warm regions with 40 - 60 inches of rainfall per
year, but with a prolonged dry season when fires are an important part of the
environment. Tropical savannas consist of grasslands with scattered clumps
of trees.
The largest savanna is in Africa occupying 1/3 of the area of Southern Africa,
but others occur in South America and Australia. Diversity of flora is not
great. The diversity and abundance of hoofed animals in the African
savanna is unequaled any where else in the world. Antelope, wildebeest,
zebra, and giraffe graze, and are sought by lions and other predators.
Termites are especially abundant in the tropical
savannas of the world, and their tall termitarias
are conspicuous elements of the savanna
landscape
Temperate Deciduous Forest Biome
Occupy areas of abundant, evenly
distributed rainfall (30-60˝ per year)
and moderate temperatures that
exhibit seasonal patterns.
Characterized by trees that loose their
leaves in the winter=deciduous.
Found in eastern N. America, Europe, parts of Japan, Australia, and the tip
of S. America.
Many plants produce pulpy fruits and nuts.
The soil is fertile. In fact, some of the great
agricultural regions are found in this biome.
That is one of the reasons there are not
many original deciduous forests left in the
world. Almost all of the forests in North
America are second growth forests but it
still has the biggest variety of original plant species. In Europe there are
only a few species of original trees left. Most of the forests have been
cleared for agriculture.
A few common animals found in the deciduous forest are, deer, bear, gray
squirrels, mice, raccoons, bobcats, wild turkey, salamanders, snakes, frogs
and many types of insects.
Broad-Leafed Evergreen Subtropical Forest Biome
Subtropical areas where moisture remains high and temperature
differences are not pronounced.
The temperate deciduous forest gives way to the broadleaf evergreen
forest climax. This community is well developed in the warm temperate
marine climate of central and southern
Japan, and the subtropical regions of N.
America, along the Atlantic and Gulf Coasts,
the Caribbean, Florida Everglades and
Keys.
Characterized by live oaks, magnolias,
palms. Oaks and other trees may support
epiphytes (Spanish moss) and lichens.
Animals similar to deciduous forest biome.
Tropical Rain Forest Biome
The variety of life reaches its peak in the broad-leafed evergreen tropical
rain forest which occupies low altitude zones near the equator. Rainfall
exceeds 80- 90˝ per year with one or more dry seasons (5˝ per month or
less).
Rain forests occur in three main areas:
1. The Amazon (South America) and the
Central American Isthmus
2. The Congo-Niger & Zambezi basins of
central Africa and Madagascar.
3. The Indo-Malay-Borneo-New Guinea regions of
SE Asia & Australia
They differ in species present since they occupy different biogeographical
regions but the forest structure and ecology is similar in all three regions.
The rain forest is highly stratified. Trees
generally form three layers resulting in the
stratification of animal life.
1. Emergents - Scattered very tall trees
projecting above the canopy (forest
giants). They house many birds and
insects.
2. Canopy - An evergreen carpet 80-100 ft
tall. This leafy environment is full of life. It
includes: insects, birds, reptiles, mammals,
and more.
3. Understory - Consisting of short, broad-leafed plants, vines, and
seedlings. It becomes dense only where there is a break in the
canopy.
4. Forest Floor - Consisting of forest litter in various stages of
decomposition. The floor is rich with animal life, especially insects.
The largest animals in the rainforest generally live here
Diversity reaches its peak in the rain forest. A much larger proportion of
animals lives in the upper layer of the vegetation than in temperate forests
where most animal life is near ground level.
Rain forests are rich in abundance of arboreal mammals, reptiles like
chameleons, geckos, iguanas, snakes as well as many birds. Fruit and
termites are staple foods.
More than half of the different kinds
animals and plants in the world live in the
tropical rain forests. The abundant sunlight,
warm temperatures, and daily rain lead to a
fast turnover of nutrients, and plant growth is
rapid. More than half of the different kinds
animals and plants in the world live in the
tropical rain forests.
Looking at the plant life, it is easy to think that
the soil is rich, but it is actually nutrient poor.
Northern Coniferous Forest (Taiga) (Boreal Forest) Biome
This is the largest biome. It is found in the northern hemisphere close to
the polar region. This cold biome stretches across the northern portions of
North America, Europe, and Asia. Large population centers, such as
Moscow and Toronto, can be found in the southern portion of this biome,
but the northern portion is relatively unpopulated.
The biome is also called the Boreal Forest or Taiga
(Russian for “land of little sticks”). Identifying life forms
include needle-leafed evergreen tree (spruces, firs,
pines). Boreal forests are among the great lumberproducing regions of the world.
Compared to the arctic tundra, the climate of the
boreal forest is characterized by a longer and
warmer growing season. Precipitation averages 20
inches per year, but ranges from 40 inches in the
eastern regions to 10 inches in interior of Alaska.
Animals such as moose, snowshoe hare and grouse
are dependent, in part, on broad-leafed developmental
communities.
Tundra Biome
The Arctic tundra is found across northern Alaska,
Canada, and Siberia. This biome has long cold winters
and short cool summers. The Arctic tundra has low
precipitation (less than 10 inches per year) and dry
winds. These conditions make the Arctic tundra a desertlike climate. The word “tundra” means “a treeless plain”.
At lower latitudes, a similar landscape is found on the
peaks of tall mountains (alpine tundra).
Chief limiting factors are low temperatures and
short growing seasons
Ground remains frozen except for the upper
few inches during the short (60-day) growing
season. (Permafrost is permanently frozen)
Major herbivores of the tundra include
waterfowl, ptarmigan, lemmings, hares,
musk ox, caribou. In some parts of the
tundra, lemmings are the dominant herbivore.
A major carnivore is the Arctic fox.
Lemmings:
Lemming suicide is fiction. Contrary to
popular belief, lemmings do not periodically
hurl themselves off of cliffs and into the
sea. Cyclical explosions in population do
occasionally induce lemmings to attempt to
migrate to areas of lesser population density.
When such a migration occurs, some
lemmings die by falling over cliffs or
drowning in lakes or rivers. These deaths are
not deliberate "suicide" attempts, however,
but accidental deaths resulting from the
lemmings' venturing into unfamiliar
territories and being crowded and pushed
over dangerous ledges. In fact, when the
competition for food, space, or mates
becomes too intense, lemmings are much
more likely to kill each other than to kill
themselves.
Vegetation - The number of plant species on the tundra is few, and
their growth is low, with most of the biomass concentrated in the
roots. The growing season is short, and plants are more likely to
reproduce asexually by division than sexually by flower pollination.
Typical arctic vegetation consists of cotton sedge and
dwarf woody plants like willows with associated
mosses and lichens. These plant communities are
adapted to sweeping winds. They carry on photosynthesis
at low temperatures, low light intensities, and long periods
of daylight.
Plant communities of the alpine tundra consist of matmaking and cushion-forming plants. These plants
are rare in the Arctic. They are adapted to gusting
winds, heavy snows, and widely ranging temperatures.
They carry on photosynthesis under brilliant light in
short periods of daylight.
cotton sedge
cushion plants
Cushion plants grow in a low, tight clumps and look like small cushions.
Cushion plants are more common in the alpine tundra where their growth
form helps protect them from the cold.