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

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50

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J F M A M J J A S O N D

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cip

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(m

m)

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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