BIOMES
Definition
Biome is a large geographical area characterized by similar
conditions of plantas, animals and climate.
A biome has many ecosystems.
Biome
Animals
Plants
Climate
Polar biomes:
Tundra
Boreal forest
Temperate biomes:
Temperate forest
Mediterranean forest
Steppe
Tropical forest:
Desert
Savanna
Rainforest
Azonal biomes:
ALPINEe forest
Mangrove
Distribution
Macaronesia
Rainforest
Rainforest is found in areas of equatorial climate, characterized
by regular and very high precipitation and very low thermal
amplitude.
Rainforest
Rainforest is characterized by a very dense arboreal vegetation
because of the high humidity.
These trees may reach 50 m tall.
Rainforest
Rainforest contains 70% of the world’s biodiversity.
There are 200 especies of trees per hectare roughly.
Rainforest
However, there are no more than one or two individuals of the
same species per hectare. This is the reason why economical
exploitation of rainforest is so difficult.
Rainforest
Although rainforest is a very especies-rich biome, its soil is very
poor. Actually the huge quantity of decaying plants is the reason
why the vegetation is so exuberant. The deforestation of these
areas in order to grow crops is consequently useless.
Rainforest
Trees have roots near the surface (buttress roots) as there are
not many nutrients below the ground.
Rainforest
Rainforest supports a rich flora of epiphytes (plants that grow
upon another plant), including orchids, mosses, lianas and
lichens, who live attached to the branches of trees.
They obtain moisture and nutrients from the air and rain.
Mosses Lianas Orchids
Rainforest
Canopy is the upper layer of rainforest.
Many rainforest animals have evolved to live solely in the
canopy, and never touch the ground.
Rainforest
Most of rainforest animals are frugivores (fruit eaters) and
arboreal: primates (chimpanzee, gibbon, bonobo, orang-utan,
etc.), sloths, flying fox, toucans…
Chimpanzee Gibbon Bonobo Orang-utan Sloth Flying fox Toucan
Civet
Rainforest
Predator are small and able to climb trees: civet, ocelot, jaguar
and leopard.
Their eyes are adapted to see during the night. This is the
reason why their pupils sometimes appear to glow.
Ocelot Jaguar Leopard Impala carcass Black panther (melanistic leopard)
Rainforest
Leopards often stash their recent kills high up in a tree. They
have been observed hauling carcasses estimated to weigh up
to 125 kg, 3 times the weight of the leopard, up to 5 m into
trees.
Rainforest
Some rainforest animals are able to change their skin colors in
order to blend it with their surroundings, as an effective form of
camouglage.
Examples include chameleons, geckos, stick insects…
Chameleon Gecko Stick insect
Savanna
Savanna is found in tropical areas characterized by a dry
season and very low thermal amplitude.
Savanna
A savanna is characterized by the trees widely spaced so that
the canopy does not close. The open canopy allows sufficient
light to reach the ground to support an unbroken herbaceous
layer consisting primarily of grasslands and shrublands.
Savanna
There are different types of savanna depending on the density
of trees and shrubs: shrub savanna, thornbush savanna, tree
savanna…
Shrub savanna Thornbush savanna Tree savanna
Savanna
Savanna trees are drought-tolerant.
For example, baobabs store water inside the swollen trunk (up
to 120,000 litres to endure the harsh drought conditions.
Savanna
Gallery forests form as corridors along rivers into savanna. The
river provides humidity resulting in a kind of microclimate. As a
result, these forests are able to exist where the surrounding
landscape wouldn’t support this vegetation.
Savanna
Savanna is the animal-biodiversity richest biome in the world.
There are a lot of ruminants mammals: zebras, elephants,
giraffes or antilopes (gnus, gazelles, impalas…).
Zebras Elephant Giraffe Gnu Gazelle Impala
Savanna
Detritivores insects play a very important role: beetles break
down animal debris an termites, which build large nests called
termite mounds, feed on dead plant material.
Beetle Termites Termite mound
Savanna
Ruminants mammals need to make an annual migration to new
pastures because of the dry season. When they are crossing
the rivers, many are eaten by predators such as crocodiles,
lions or cheetahs, which reach speeds of 20 kmh.
Crocodile Lion Cheetahs
Savanna
Nile crocodile is an agile and rapid hunter.
Savanna
Competition for preys is often intense.
Desert
Deserts are found in tropical areas characterized by a very low
precipitation and, usually, high temperature.
Evaporation is higher than precipitation.
Desert
Plants are xerophytes: they have adaptations that enable them
to survive in hot and dry environments. For example, cacti store
water in their bodies and have spines which not only defend the
cactus against herbivores but also provide shade.
Cactus
Desert
Deserts support very little life. Some herbivore fauna includes
antilopes (oryx) and rodents (rabbits, kangaroo rats, etc.).
They usually remain hidden during daylight hours to control
body temperature or to limit moisture needs.
Oryx Rabbit Kangaroo rat
Desert
Kangaroo rats have special adaptations to live in arid
conditions: they live in deep burrows that shelter them from the
worst of the desert heat and their kidneys are at least four times
more efficient at retaining water than those of humans.
Desert
Desert predators include the fennec fox and the jackal (leopards
and lions have disappeared because of the mankind).
There are also a lot of poisonous reptiles: horned viper, Gila
monster…
Fennec fox Jackal Leopard Horned viper Gila monster
Desert
Some desert carnivore are scavangers, such as the striped
hyena and the vultures.
The striped hyena is primarily a scavenger, though it will
occasionally attack any defenceless animal it can overcome.
Striped hyena
Vultures
Schlerophyll
forest
Schlerophyll or mediterranean forest is found in areas with a
mediterranean climate, characterized by a dry season in
summer.
Trees are adapted to high insolation and summer drought
(xerophytes): wide crown to provide shade; leathery leaves to
decrease transpiration; deep roots to take the most of soil
moisture…
Leathery leaves
Schlerophyll
forest
Vegetal species include Cork Oak, which has a thick bark to
shelter it from the summer fires, and Holm Oak, which is
adapted to cold winters.
The most common tree in Australia is Eucalyptus.
Cork Oak Holm Oak Eucalyptus
Schlerophyll
forest
The trees are widely spaced, so they allow sufficient light to
reach the ground. It results in a rich undergrowth.
Schlerophyll
forest
The forest degradation results in a drought-tolerant and thick
shrubland called maquis. When the shrubland is not so thick, it
is called garriga..
Maquis
Schlerophyll
forest
Garriga
Dehesa is a type of wooded pastureland found in the Iberian
peninsula, used for the grazing of livestock (bulls, pigs) and the
obtention of forest products such as cork, wild game,
mushrooms, and firewood.
Pigs Bull Cork (saca del corcho) Cork Mushrooms Wild game
Schlerophyll
forest
This region is home to herbivores mammals, such as Roe Deer,
rabbit and squirrel, and omnivores such as wild boar or
European Badger. Predators include Red Fox, Lynx, Least
Weasel and eagle.
Roe Deer Rabbit Squirrel Wild Boar European Badger Red Fox Lynx Least Weasel Eagle
Schlerophyll
forest
Eagles have extremely keen eyesight which enables them to
spot potential prey from a very long distance. Eagles are able to
carry very large preys.
Schlerophyll
forest
Australia isolation has allowed the conservation of a lot of
endemisms, organisms unique to a defined geographic location:
platypus, marsupials (koala and kangaroo), etc.
Platypus Koala Kangaroo
Schlerophyll
forest
Temperate
forest
Temperate forest is found in temperate climates characterized
by high and regular precipitation, such as the humid subtropical
climate or the oceanic climate.
English Oak is a large deciduous tree (lose their leaves in
winter). The wood is very hard and grow very slowly (200
years). The undergrowth is formed by mosses and ferns.
English Oak Undergrowth
Temperate
forest
Hare
Temperate forest fauna is similar to schlerophyll forest fauna,
but more diverse because of the high humidity. Animals are well
adapted to cold winters: bigger size (hare), thick furs (beaver,
marten), hibernation (brown bear), etc.
Beaver Marten Brown bear
Temperate
forest
Steppes are located in the interior of continents. They are
characterized by low precipitation and very high thermal
amplitude because of the remoteness from the sea.
Steppe
Steppe is characterized by large grasslands and shrublands.
There are different types of savanna depending on the density
of trees and shrubs: wooded steppe, shrub steppe, thornbush
steppe…
Steppe
Steppes and savannas are both grasslands with no trees. Both
are arid, but steppes are located in temperate climates and
savannas are located in tropical climates.
Steppe
Nowadays steppe fauna is not very diverse because of
agriculture and animal husbandry. It includes bison, guanaco,
rhea, cougar, coyote, stag…
Steppe
Bison Guanaco Rhea Cougar Coyote Stag
This is an example of cougar hunting a stag.
Steppe
Boreal forest or taiga is located in subpolar areas characterized
by high precipitation and cold winters.
Boreal forest
Taiga is a biome characterized by coniferous forests. It is the
world's largest terrestrial biome (28% of the wordl) and covers
most of Canada and Alaska, most of Scandinavian peninsula,
much of Russia (especially Siberia) and northern Japan.
Boreal forest
Conifers (pines, firs, etc.) have many winter time adaptations:
their narrow conical shape help them shed snow; their wood is
soft to resist the temperature changes; their needle leaves are
able to resist frosts...
Pine Fir Needle pine Needle fir
Boreal forest
Conifers roots are not very deep to avoid the permafrost, soil
below the freezing point of water (0 °C) for years. Thickness of
the active layer varies by year and location, but is 0.6–4 m thick.
Boreal forest
Permafrost contains a huge quantity of methane, a powerful
greenhouse gas.
Boreal forest
The taiga is home to large herbivorous mammals, such as the
moose, the reindeer and the arctic hare which eat lichens, the
dormouse and the lemming, which eat cones, and the muskrat,
that inhabits wetlands (marshlands, rivers, lakes or ponds).
Moose Reindeer Arctic hare Dormhouse Lemming Cones Muskrat
Boreal forest
Dormice are particularly known for their long periods of
hibernation. They can hibernate six months or even longer,
sometimes waking for brief periods to eat food they had
previously stored nearby.
Boreal forest
Predators include wolves, which still exist in this biome, bears
such as the koadiak and the grizzly, the otter, whose fur is
extremely valuable, and the siberian tiger.
Wolf Kodiak Kodiak bear hunted Grizzly Otter Siberian tiger
Boreal forest
The siberian tiger is the largest living felid, attaining 120 cm tall,
370 cm long and 320 kg.
Boreal forest
Tundra is located in circumpolar regions characterized by very
cold temperatures: average monthly temperature is always
lower than 10 ºC.
Tundra
The layer of soil free of permafrost is too thin to allow the
existence of trees, as the roots cannot get bellow it.
As a result, flora includes only mosses and lichens.
Tundra
Tundra in summer Lichens
These plants grow very slowly because of the harsh climatic
conditions (they often take several years to grow) and
consequently the herbivores such as the lemming, the moose
and the muskox must periodically migrate.
Tundra
Muskox
Every year summer leads to life explosion: the meltwater results
in the formation of a lot of ponds and lakes. These bodies of
water are home to marsh plants such as the water lillies, which
atract a lot of mosquitoes.
Tundra
Ponds in the tundra Water lillies Mosquito
In spring, migratory birds such as the swan and the goose fly
north long distances to breed in the tundra summer. The
primary motivations are food and longer days, which provide
extended time for breeding birds to feed their young.
Tundra
Swan Migration of swans Gooses flying
Tundra predators, such as the stoat and the arctic fox, have a
thick white fur to blend into their environment.
Tundra
Stoat Arctic fox in summer Arctic fox in winter
In areas located at latitudes higher than 70º North, vegetation
completely disappears because of the extremely harsh
conditions. However, these regions are home to polar bears,
which hunt aquatic mammals such as seals or walruses.
Tundra
Polar bear Seal Elephant seal Walrus
These aquatic mammals, which are shielded from extreme cold
by their blubber, eat krill, the name given to a group of tiny
crustaceans found in the oceans.
Tundra
Krill
The polar bear is the largest terrestrial carnivore. Adult males
weigh 600 kg.
Tundra
Mangrove
Mangroves are located in tropical coastal areas characterised
by a warm and rainy climate, such as the equatorial climate or
the monsoon climate.
Mangrove
Mangroves are found in tropical tidal areas. Areas where
mangroves or mangals occur include estuaries and river deltas,
such as the Ganges Delta.
Mangrove
Mangroves or mangals are various kinds of trees found in this
biome. They have a lot of adaptations to survive in inundated
areas.
Mangrove
Mangroves are halophyles (organisms that live in environments
with very high concentrations of salt). For example, their roots
filter the salt and their leaves are able to secrete salt.leaf
Inundated mangrove Mangrove leaf
Mangrove
The aerial roots are an adaptation to these harsh conditions:
stilt roots increase height and maintain mechanical stability and
pneumatophores enable plants to breathe air in habitats
covered by water.
Stilt roots in the low tide Stilt roots in the high tide Pneumatophores in the low tide Pneumatophores in a high tide
Mangrove
Mangroves are an excellent natural barrier to hurricanes and
tsunamis.
Mangrove
Most of mangrove animals are arboreal, such as primates
(macaques, long-nosed monkey…) and birds (ibis), or
amphibians such as the crustaceans (fiddler crab), frogs or
some fishes.
Macaque Long-nosed monkey Ibis Fiddler crab Frog
Mangrove
The mudskipper is an amphibian fish that can breathe through
their skin and use their fins to walk on land in a series of skips.
These fishes can see all around itself with their bulging eyes.
Mudkipper in the water Mudskipper on the mud Mudskipper on a mangrove
Mangrove
Predators include felids such as the Bengal tiger and the fishing
cat, which are skilled swimmers.
A bengal tiger can kill 30 water buffalos every year.
Fishing cat Bengal tiger Water buffalo White tiger
Mangrove
The average weight of Bengal tiger males is 221.2 kg. They are
very dangerous.
Mangrove
There are a lot of aquatic reptiles, such as the turtle, the water
monitor, the python (a constrictor snake 7 m long) and the
saltwater crocodile
Tortue Varan malais Python Crocodile marin
Mangrove
Constriction is a method used by various snake species such as
pythons to kill their prey.
Mangrove
An adult male saltwater crocodile's weight is 1,300 kg and
length is 6 metres.
Mountain
The mountain forest is located in areas at high altitude (roughly
2 000 m in middle latitudes).
Is is often characterised by high precipitation and low
temperature.
-40
-20
0
20
40
60
80
100
120
140
160
-20
-10
0
10
20
30
40
50
60
70
80
J F M A M J J A S O N D
Pre
cip
itation
(m
m)
Tem
pera
ture
Altitude: 1 560 m Latitude: 46 ºN
Average temperature: 2,8 ºC Annual precipitation: 999 mm
Mountain
The relief is a key factor which will determine the vegetal
distribution of these areas because of the föhn wind.
10 ºC
5 ºC
0 ºC
10 ºC
20 ºC
Mountain
The vegetation in mountain areas is distributed in levels
according to the latitude.
A cliserie is a graphical representation of these levels.
Holm Oak English Oak Common Beech Conifer Meadow
N S Pyrenees
ALPINE
MOUNTAIN
BASAL
2 000 m
1 000 m
Mountain
Maquis Holm Oak English Oak Meadow
N S Sierra Nevada
ALPINE
MOUNTAIN
BASAL
2 000 m
1 000 m
The vegetation in mountain areas is distributed in levels
according to the latitude.
A cliserie is a graphical representation of these levels.
Mountain
N S Cantabrian mountains
ALPINE
MOUNTAIN
BASAL
2 000 m
1 000 m
Holm Oak English Oak Common Beech Meadow
The vegetation in mountain areas is distributed in levels
according to the latitude.
A cliserie is a graphical representation of these levels.
Macaronesia
Macaronesia is a group of archipels in the North Atlantic Ocean:
Azores, Madeira, Savage Islands, Canary Islands and Cape
Verde.
Macaronesia
The vegetation of Macaronesia is considered an example of
relict: relict is an organism that at an earlier time was abundant
in a large area but now occurs at only one or a few small areas.
Macaronesia
The vegetation of Macaronesia is extremely affected by the
altitude and the trade winds. It results in the formation of
microclimates.
Cardón Juniper Laurel forest Canary Pine
N S Teide
SUPRACANARY
THERMOCANARY
BASAL
2 000 m
750 m
500 m
1 000 m
INTERMEDIATE
CANARY
Trade winds
Bushes