Biomes, or ecosystems, are large regions of the planet with shared characteristics such as climate, soils, plants and animals. Climate is an important factor that shapes the nature of an ecosystem, as well as precipitation, humidity, elevation, topography and latitude.
The five major biomes include aquatic, desert, forest, grassland and tundra biomes. Each biome also includes numerous types of sub-habitats.
By protecting and preserving ecosystems, we protect and preserve plant and animal species…including our own species.
The aquatic biome includes habitats around the world dominated by water. Aquatic ecosystems are divided into two main groups based on their salinity—freshwater habitats and marine habitats.
● Freshwater habitats are aquatic habitats with low levels of salt, less than one percent. They include rivers, lakes, streams, ponds, swamps, wetlands, bogs and lagoons.
● Marine habitats are aquatic habitats with salt concentrations of more than one percent. They include oceans, seas and coral reefs.
Some habitats exist where saltwater and freshwater mix together. These include mud flats, mangroves and salt marshes. Aquatic ecosystems support a diverse assortment of animals including fishes, amphibians, reptiles, mammals, birds and invertebrates.
When evaporated sea water falls as rain, it flows down mountain streams creating rivers and lakes. Rain water feeds freshwater rivers, which then flows back into the sea. Streams, rivers and lakes are home to countless animal species.
The two main types of freshwater habitat are rivers and lakes. Lakes are often fed by streams or rivers. They can also be enclosed areas where species live that are found nowhere else on the planet. Rivers usually contain large animals able to cope with strong currents, as well as animals such as crabs and birds that feed on the fish within the water.
Freshwater rivers provide habitat to a wide variety of species including fish, amphibians, reptiles, insects, birds and mammals. An extraordinary number of fish species inhabit streams and rivers.
Freshwater lakes are also home to a vast variety of wildlife. Some species spend their entire lives in one area. Others visit momentarily to eat and drink. Many species are specially adapted to life in particular lakes. Large mammals, including zebras, primates, giraffes and deer, visit lakes to drink.
Many freshwater habitats have been drastically affected by human activities. Chemicals and pesticides contaminate the water, as well as waste water. Animals and plants that inhabit the water can be affected, as are the animals that eat them.
Oceans create the largest habitat in the world. Countless animal species inhabit the planet’s oceans which cover over 75% of the earth.
The two main types of ocean habitat are coastal, inshore habitats found around land, and open ocean habitats that stretch around the planet. More animal species live in the rich, shallower waters than the deep sea, though animals live throughout the oceans.
The ocean landscape is as vast and varied as on land, featuring underwater continental shelves, mountains, valleys, volcanoes, trenches and plains.
Warmer, coastal waters around the globe are home to the majority of species. These areas feature more food sources than the deep ocean. Smaller aquatic animals often inhabit the shallower regions. Coastal waters provide them with a variety of places to hide, with fewer large predators. Larger animals tend to prefer deeper regions beneath the waves along the continental shelves.
Plankton — microscopic plants and animals, fish eggs and animals in their larvae form — provide a plentiful food source for many marine animals. Tiny fishes and crustaceans, to the largest animal on the planet, the blue whale, feed on this vital food source.
The two largest threats to ocean habitats are over-fishing and pollution. Pollution from the land and air accumulate in the sea with devastating effects to many plant and animal species. Over-fishing threatens many species with extinction.
Coral reefs are the richest habitats on the earth. Found along the coastlines, they provide habitat to countless plant and animal species including fish, reptiles, invertebrates, echinoderms and crustaceans. Coral reefs are located in the tropical and sub-tropical coastal regions where it is always warm, day and night, year-round.
The two main types of coral reef habitats are soft coral reefs and hard coral reefs. Soft corals are animals that move through the water, eventually settling. Hard corals are the reef-building corals that are hard coral shells left behind when corals die.
The largest coral reefs are located along the south-west coast of Africa, in the Caribbean and all around Australia, south-east Asia and the coastal regions of the South Pacific Ocean.
So rich in life and biodiversity, coral reefs are home to an incredible variety animal species able to survive together with little competition for food. Animal species that inhabit coral reefs vary tremendously in shape, size and color. Sea urchins, starfish and crustaceans are invertebrates that call coral reefs home. Sea snakes hunt small fish and eels in the coral reefs. Eels and seahorses are among the many fish species. Sharks do not live permanently in coral reefs, but visit often in search of prey. Sea turtles also make frequent trips to coral reefs in search of food.
The threats to coral reefs and coastline wildlife include commercial fishing, pollution and storms. Dredging involves dragging fishing nets across the sea bed, destroying coral reefs in the process. Many animal species that inhabit coral reefs are on the brink of extinction. Sea storms, such as tsunamis, can also reek havoc on coral reef environments.
Wetlands are found throughout the world, often in more temperate regions where vegetation grows quickly. These large areas of water contain a wealth of plants and are broken up by small islands of land. Wetlands include swamps, marshes, fens and bogs. Many wildlife species are specifically adapted to wetland environments, including fish, amphibians, birds, mammals, reptiles and insects.
The two main types of shallow watery areas are swamps and wetlands. Swamps are usually located in forested areas. Trees, such as mangrove trees, survive in salt-water conditions and require ample space for their roots. Wetlands are usually near large rivers or estuaries that flood when river banks burst from a lot of rain.
Mangrove swamps are one of the richest habitats on the planet. Numerous animals species live above and below the water’s surface. Many animal species that live in mangrove forests are found nowhere else on earth. The mangrove tree’s enormous roots provide shelter to small fishes, amphibians and reptiles and provide a way for the animals to get in and out of the water. Larger animals have ample fish to feed on.
Large aquatic birds such as heron spear fish with long beaks in wetland habitats. Salt-water swamps contain snapping turtles, crabs, crocodiles and alligators. Amphibians and reptiles inhabit the water’s edge. Many insects live, and lay their eggs, in wetland habitats…providing food for frogs and lizards.
The main threats to wetlands are deforestation and pollution. The animals in wetland habitats are specifically adapted to their environment and are vulnerable to toxins in the water and air.
Islands form when land breaks away from large land masses or volcanoes erupt on the sea floor. They are found throughout the world. Their isolated nature results in unique wildlife species, often different from their counterparts living in mainland habitats. Some island animal species have developed completely separately from mainland species.
Numerous habitats including forests, wetlands, deserts and tundra can be found on different islands. Limited in size and resources, ecosystems on islands are fragile and easily disturbed. Human activity and the introduction of new species on islands has caused much harm, making many species endangered or extinct. With nowhere else for them to go, the loss of habitat or food sources is particularly damaging to island animals.
Lemurs live only on the island of Madagascar, the tree kangaroo only in Papua New Guinea, the kiwi only in New Zealand and the orangutan only on the Indonesian islands of Borneo and Sumatra. Separated from the mainland, these species have adapted to their isolated environments. The kiwi and the kakapo birds have adapted to a flightless lifestyle since there were no large predators on the islands to flee from. The introduction of predators by humans threatens their survival. Orangutans suffer from mass deforestation in south-east Asia and the exotic pet trade.
A breaking point has been reached in conserving the fragile habitats of islands. Without immediate action to save these precious ecosystems, many species will be lost forever.
Forest biomes are dominated by trees and extend over one-third of the earth’s land surface. There are three main types of forests—temperate, tropical and boreal. Each type has a different assortment of animals, climate characteristics and species compositions.
● Temperate forests are in temperate regions of the earth including North America, Europe and Asia. They have four well-defined seasons and a growing season between 140 and 200 days. Rainfall takes place throughout the year and soils are nutrient-rich.
● Tropical forests are located in equatorial regions between 23.5°N and 23.5°S latitude. They experience two seasons, a dry season and a rainy season. The length of each day varies little throughout the year. Soils in tropical forests are nutrient-poor and acidic.
● Boreal forests make up the largest terrestrial habitat. They are a band of coniferous forests located in the high northern latitudes between about 50°N and 70°N. Boreal forests create a circumpolar band of habitat from Canada, to northern Europe, to eastern Russia. They are bordered by tundra habitat to the north and temperate forest habitat to the south.
Some of the wildlife that inhabit the forest biome include deer, bears, wolves, moose, caribou, gorillas, squirrels, chipmunks, birds, reptiles and insects.
Temperate forests are found in a wide range of climates and are some of the richest habitats earth. Temperate forests are home to a variety of plants and animals. Some live within them year-round, while migratory animals visit them seasonally.
The two main types of temperate forests are deciduous forests and evergreen forests.
Deciduous forests contain trees that loose their leaves in the fall. They are usually located in the Northern Hemisphere in parts of North America, Europe and Japan.
Evergreen forests are made up of trees that don’t lose their leaves in the fall. They usually are found in warmer climates in South America, southern Europe, South Africa and parts of southern Australia. A more varied range of wildlife is often found in evergreen forests than deciduous forests.
A wide variety of animals call temperate forests home. Mammals, reptiles, amphibians, birds and insects live in temperate forests. The most common mammals are deer, squirrels, birds and wild boars.
Since food is plentiful in evergreen forests year round, even more varieties of wildlife inhabit them. Reptiles, amphibians, birds, mammals and insects are plentiful in evergreen forests.
Temperate forests once covered huge areas of the Northern Hemisphere. As a result of logging and deforestation for agriculture, most forests are already gone.
Coniferous forests are located in the far north, many within the Arctic Circle. They are predominantly home to conifers, the toughest and longest living trees. Conifers grow close together resulting in dense forests that are sheltered.
Coniferous forests include boreal forests and temperate forests.
Boreal forests stretch across the far north. Temperate coniferous forests are located in western North America, New Zealand and Chile. Some trees in the temperate coniferous forests in North America are over 500 years old.
Boreal coniferous forests stretch across the far north from Siberia, through Northern Europe, to Alaska, covering a distance of 6 million square miles. They are 1,000 miles wide in places. A large proportion of boreal coniferous forest is in the Arctic Circle, where plants and animals are well adapted to cold temperatures.
While fewer plant and animal species are found in coniferous forests compared to temperate forests and rainforests, many plants and animals still live within them. Conifer trees withstand the cold. Their pine needles are acidic, which passes into the soil when needles drop, allowing only acid loving plants to survive in coniferous forests. Only herbivores that survive on acidic plants can inhabit coniferous forests.
Insects make up the majority of animals found in coniferous forests. The dense trees provide ideal habitat for them to build their nests. Deer, elk, wolves and bears are also common in coniferous forests.
Coniferous forests are the least affected forests by humans. The trees are softwood and usually only used for making paper. Larger areas of coniferous forests are being logged however, as paper demand increases.
Rainforests are home to more than 50% of all living species on the planet. They receive an abundance of rain and contain extremely diverse wildlife. The two main types of rainforest are tropical rainforests and seasonal rainforests.
Tropical rainforests are close to the Equator where the climate is warm, providing ideal conditions for plants. 170,000 of the world’s 250,000 known plant species are found in tropical rainforests. They have various layers of canopy providing a wide variety of habitats for animals. A large collection of tall tree species is made possible by a constant water flow. Tropical forests are home to smaller primates and bird species than seasonal rainforests.
Seasonal rainforests are usually further away from the Equator. Their climate is less stable then tropical rainforests. Rather than rain being dispersed evenly throughout the year, it comes all at once in what is called the monsoon. Trees in seasonal rainforests are generally much smaller than those in tropical rainforests. Larger animals inhabit the changing seasonal rainforests, such as tigers, primates and large snakes.
The broad array of animals found in rainforests include mammals, reptiles, birds and invertebrates. Mammals include primates, wildcats and tapirs. Reptiles include a variety of snakes, turtles and lizards. Numerous species of birds and insects live in rainforests. Fungi is common, which feed on the decomposing remains of plants and animals. Many animal species have adopted a tree-dwelling (arboreal) lifestyle in the rainforest. Food is abundant in the forests due to the amount of water and plant life.
Numerous plant and animal species are rapidly disappearing from rainforests due to deforestation, habitat loss and other human activities. Around 50 million people live in rainforests. Their habitat and culture is also threatened as an alarming amount of rainforest land disappears each year.
Desert biomes receive very little rain and cover about one-fifth of the planet’s surface. They are divided into four sub-habitats based on their location, aridity, climate and temperature: arid deserts, semi-arid deserts, coastal deserts and cold deserts.
● Arid deserts are hot and dry and are located at low latitudes throughout the world. Temperatures are warm all year and hottest during the summer. Arid deserts receive little rainfall, and most rain that does fall usually evaporates. Arid deserts are located in North America, South America, Central America, Africa, Australia and Southern Asia.
● Semi-arid deserts are usually not as hot and dry as arid deserts. They have long, dry summers and cool winters with some rain. Semi arid deserts are found in North America, Europe, Asia, Newfoundland and Greenland.
● Coastal deserts are usually located on the western edges of continents at approximately 23°N and 23°S latitude, the Tropic of Cancer and the Tropic of Capricorn. Cold ocean currents run parallel to the coast, producing heavy fogs. Despite high humidity in coastal deserts, it rarely rains.
● Cold deserts have low temperatures and long winters and are found above the treelines of mountain ranges and in the Arctic and Antarctic. They experience more rain than other deserts. Many locations of the tundra are cold deserts.
Desert animals include coyotes, kangaroo rats, spiders, meerkats, roadrunners, reptiles, toads, snakes, pronghorn, birds and bats.
Dry and baron landscapes, deserts receive intense sunshine and little rain. They are places of extremes, with a greater range of temperatures throughout the day than any other habitats. Temperatures range from boiling in the middle of the day, to freezing at night.
The two main types of deserts are true deserts (hot deserts) and semi-deserts.
True deserts are located on either side of the tropics.
Semi-deserts occur on every continent, usually far from the tropics. Semi-deserts receive at least twice as much rain each year than true deserts.
Deserts are formed from large fluctuations in temperature between day and night which puts strain on rocks. The stress causes the rocks to break into pieces. Occasional downpours of rain cause flash floods. The rain falling on hot rocks can cause them to shatter. The rubble is strewn over the ground and further eroded by the wind. Wind-blown sand grains further break down stones, causing more sand. Rocks are smoothed down, and the wind sorts sand into deposits. The grains end up as sheets of sand.
Other deserts are flat, stony plains where all the fine material has been blown away leaving an area of smooth stones. These deserts are called desert pavements and little further erosion takes place. Some deserts include rock outcrops, exposed bedrock and clays once deposited by flowing water. Oases occur where there are underground sources of water in the form of springs and seepages from aquifers.
A unique desert is the Gobi desert in Asia which is located across China and stretches up to the Siberian Mountains where winters are very cold. Despite the cold winters, the mountains block rain-clouds from reaching the desert area.
A variety of plants and animals live in desert habitats. Plants tend to be tough and wiry with small or no leaves. Some plants germinate, bloom and die in the course of a few weeks after rainfall. Some long-lived plants survive for years with deep roots that tap into underground moisture.
Most animals are nocturnal, coming above ground or out of the shade at night when temperatures are cooler. Reptiles, insects and small birds are the most common animals in true deserts. Mammals are more common in semi-deserts, where plant life is more plentiful.
Animals of the deserts are adapted to dry and arid conditions. They are efficient at conserving water, extracting most of their needs from their food and concentrating their urine. The addax antelope, dik-dik, Grant’s gazelle and oryx never need to drink. The thorny devil in Australia sucks water through channels in its body located from its feet to its mouth. The camel minimizes its water loss by producing concentrated urine and dry dung, and is able to lose 40% of its body weight through water loss without dying of dehydration. Camels have humps of fatty tissue that concentrate body fat in one area, minimizing the insulating effect fat would have if distributed over their whole bodies. Birds are able to fly to areas of greater food availability as the desert blooms after local rainfall, and can fly to faraway waterholes. Carnivores obtain much of their water needs from the body fluids of their prey.
Flies, beetles, ants, termites, locusts, millipedes, scorpions and spiders have hard cuticles which are impervious to water and many lay their eggs underground where their young develop away from the surface temperature extremes. Some arthropods make use of the ephemeral pools that form after rain and complete their life cycle in a matter of days.
Reptiles do not sweat, so they shelter during the heat of the day. In the first part of the night, as the ground radiates the heat absorbed during the day, they emerge and search for prey. Some snakes move sidewards to navigate high sand-dunes. Even amphibians have adapted to desert habitats, spending the hot dry months in deep burrows where they shed their skins numerous times to create cocoons around them to retain moisture.
Some animals remain in a state of dormancy for long periods, becoming active again when the rare rains fall. They then reproduce rapidly while conditions are favorable before returning to dormancy.
Deserts habitats have been the least affected by human activities, remaining relatively untouched. Threats do include extraction of oil from the sand and grazing farm animals that deplete desert plants, threatening wildlife that rely on those plants. Desertification can be caused by tilling for agriculture, overgrazing and deforestation.
Tundra is a cold habitat with long winters, low temperatures, permafrost soils, short vegetation, brief growing seasons and little drainage. The Alpine tundra exists on mountains around the planet at elevations above the tree line. The Arctic tundra is near the North Pole, extending southward to where coniferous forests grow.
● Arctic tundra in the Northern Hemisphere is between the North Pole and the boreal forest. In the Southern Hemisphere it exists on remote islands off the coast of Antarctica and on the Antarctic peninsula. The Arctic and Antarctic tundra are home to over 1,700 species of plants including grasses, mosses, sedges, lichens and shrubs.
● Alpine tundra is a high-altitude ecosystem located on mountains around the earth at elevations above the tree line. Alpine tundra soils are well drained compared to tundra soils. Alpine tundra is home to small shrubs, dwarf trees, tussock grasses and heaths.
The tundra is home to the arctic fox, wolverines, polar bears, northern bog lemmings, muskox, arctic terns, muskoxen and snow buntings.
Tundra are the coldest areas on the planet and are quite different from every other habitat on earth. During the summer, the days receive 24 hours of sun. During the winter, the sun is almost absent entirely. Animals of the polar regions are adapted to frigid temperatures, often with thick layers of fat or blubber to insulate their bodies.
The two main polar regions are the Arctic and the Antarctic. The Arctic Circle and Arctic Tundra are located at the North Pole and stretch 5 million square miles to the top of the Northern Hemisphere. The Antarctic is located at the South Pole. While the animals differ greatly at each pole, the polar regions are similar environments.
The Arctic is an ice continent floating on the ocean. The Antarctic is a rocky continent that is covered in ice. Little rainfall occurs in the polar regions, and there is very little water in the air. The Arctic is connected to Canada and Europe, so more plant and animal species are found there. The Antarctic is completely isolated from other land masses, so fewer plants and animals are found there. The Arctic Circle also features warmer springs and summers, encouraging the growth of plants. Herbivorous animals are attracted to feed on the plants and grasses.
1,700 species of plants and 48 species of land mammals are known to live in the tundra. Millions of birds also migrate there each year for the marshes. Few frogs or lizards live in the tundra. Foxes, lemmings, Arctic hares and Arctic owls live in the tundra. Wolves are the top predators. Polar bears dominate the frozen waters. Seals, sea lions, orcas, whales, walruses and narwhals feed on fish in the Arctic Circle.
In Antarctica, no plants grow on the surface so animals live on carnivorous diets. Numerous species of fish, crustacean and mollusc are found in the waters beneath the ice for birds and mammals to feed on. Penguins are the most common animal. Larger predators include leopard seals, orcas and whales.
Changes in the climate are the biggest threat to polar regions. Increasing temperatures can cause the ice to melt, threatening habitats. The Antarctic Treaty of 1961 prevents Antarctica from being commercially exploited. The Arctic is not protected where mining for oil and minerals, over-fishing and hunting threatens species and habitats.
Grasslands habitats are dominated by grasses with few large shrubs or trees. The three main types of grasslands include temperate grasslands, tropical grasslands or savannas and steppe grasslands. Grasslands have dry seasons and rainy seasons. They are susceptible to fires during dry seasons.
● Temperate grasslands have a lack trees and large shrubs and are dominated by grass. The soil has an upper layer that is nutrient-rich. Seasonal droughts result in fires that keep trees and shrubs from taking over the area.
● Tropical grasslands are located near the equator with warmer, wetter climates than temperate grasslands and more pronounced seasonal droughts. They are dominated by grasses, but also have scattered trees. The soil of tropical grasslands are porous and drain quickly. Tropical grasslands can be found in South America, Australia, Africa, India and Nepal.
● Steppe grasslands are dry grasslands that border on semi-arid deserts. Their grasses are much shorter than temperate and tropical grasslands and they lack trees except along rivers and streams.
Animals that inhabit grasslands include American bison, African elephants, lions and spotted hyenas.
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous (non-woody) plants. They are also known as prairies and savannas. Grasslands occur naturally on all continents except Antarctica.
Grassland habitats are located in most climates, with the grasses varying in height from very short to very tall. Woody plants, shrubs or trees are found in some grasslands – forming scrubby grassland, semi-wooded grassland or savanna such as the African savanna plains. Some grasslands are called wood-pasture or woodland.
Grasslands may occur naturally or as the result of human activity. Grassland vegetation remains dominant in a particular area usually due to grazing, cutting or natural or manmade fires, all discouraging trees and shrubs from growing. Some of the world’s largest expanses of grassland, located in Africa, are maintained mostly by wild herbivores.
Grasslands are often dependent on their region and differ around the world. In temperate areas, such as north-west Europe, they are dominated by perennial (year-round) grasses. In warmer climates, annual grasses make up most of the plant life.
Grassland habitats support a wealth of wildlife including mammals, birds, reptiles, amphibians and insects. Smaller animals are common as the open and uncovered areas make predators easier to see. Some large herbivorous mammals do also inhabit grasslands.
Grasslands once covered two thirds of the planet. As a result of human agriculture, only small pockets of original grassland ecosystems remain. Half of Africa remains grasslands.
Mountain ranges are located all around the globe. They are the result of plate movements below the planet’s crust. Mountains vary in height from small hills to Mount Everest, the tallest mountain in the world. Animals that inhabit mountainous regions must withstand dramatic temperature changes and lower oxygen levels.
The two main types of mountain ranges are temperate mountains and tropical mountains.
Temperate mountains are often cold all year and more seasonal than tropical mountains. They are found in North and South America, Europe and Central Asia. During spring and summer months a burst of plant life at high altitude occurs, encouraging herbivores up the mountain.
Tropical mountains feature warmer climates with plants adapted to high altitudes. They are located in South America, Africa and south-east Asia.
Mountain wildlife are adapted to high altitudes and changing temperatures. The higher up a mountain, the lower the temperature. Plants are usually seasonal in mountains. Those that do occur year round, such as conifers, are adapted to handling the cold temperatures.
Hoofed and herbivorous mammals, including deer, goats, llamas and sheep, are common in mountains. They are well suited to the terrain and graze on ledges and cliff faces. During the spring and summer, they move up the mountains when plants are plentiful. In the fall, they move back down the mountains in cooler weather when food is more scarce. Large predators also inhabit mountain regions, including bears and mountain lions, who prey on the herbivores. Some animal species do not live on the mountains, but inside of them. Caves provide habitat for amphibians, insects and bats.
Threats to mountain habitats include deforestation, quarrying and development. Changes in climate also affects the growth of plants at higher altitudes.
Around half of the planet’s population now lives in a city. The move towards urban living has increased city sizes tremendously with an enormous impact on ecosystems. Once wild landscapes have been transformed into urban centers, changing animal habitats both inside and outside the areas.
Animals in these areas have had to adapt. They have learned to create new homes within their artificial environments. They have also discovered new food sources, including waste created by humans. Food chains of numerous species have been altered.
Urban areas range from fully urban with little green space and mostly covered by paving or buildings, to suburban areas with gardens and parks. Different types of urban areas support different kinds of wildlife. Some animals find shelter in city parks, trees and water sources. Some live inside the city; others just outside the urban habitat. Insects, reptiles and rodents make nests inside buildings in small gaps and crevices to find shelter from the elements and protection from predators. Birds nest on buildings. Some animals live under homes and buildings. Some make homes in city sewer systems.
Animals have cleverly adapted to their changing world. Some city animals have become nocturnal, using city lights to aid in finding prey. Feral dogs have learned to use subway systems. Urban monkeys and penguins raid human homes to take food. Some steal fruit from vendors. Older deer learn to look both ways before crossing streets. Birds flock to city centers to snack on the food dropped in the streets.
Numerous threats for urban animals include traffic, litter, pollution, noise pollution, bright lighting and lack of space. It is important to reserve space within urban environments for wildlife, and to conserve natural environments outside cities.