The savanna biome, which is a type of grassland biome, consists of areas of open grassland with very few trees. There are two kinds of savannas: tropical and semi-tropical savannas.
- Grasslands are located on every continent except Antarctica.
- The largest savannas are located in Africa near the equator.
- One of the most famous African savannas is Serengeti National Park in Tanzania, which is known for its large wildebeest and zebra populations. The park is also home to lions, leopards, elephants, hippos, and gazelles.
- Other locations of savannas include:
- Africa: Kenya, Zimbabwe, Botswana, South Africa, and Namibia
- Central America: Belize and Honduras
- South America: Venezuela and Columbia
- Southern Asia
- The savanna climate varies according to the season.
- In the wet season, weather is warm and a savanna receives as much as 50 inches of rain.
- But during the dry season, weather can be extremely hot, and rainfall will amount to only four inches each month.
- This combination of high temperatures and little precipitation makes savannas perfect areas for grass and brush fires during their dry seasons.
- The savanna biome is often described as an area of grassland with dispersed trees or clusters of trees.
- The lack of water makes the savanna a difficult place for tall plants such as trees to grow.
- Grasses and trees that grow in the savanna have adapted to life with little water and hot temperatures.
- Grasses, for example, grow quickly in the wet season when water is abundant and turn brown in the dry season to conserve water.
- Some trees store water in their roots and only produce leaves during the wet season.
- Due to frequent fires, grasses are short and close to the ground and some plants are fire resistant.
- Examples of vegetation in the savanna include wild grasses, shrubs, baobab trees, and acacia trees.
- The savanna is home to many large land mammals, including elephants, giraffes, zebras, rhinoceroses, buffalo, lions, leopards, and cheetahs.
- Other animals include baboons, crocodiles, antelopes, meerkats, ants, termites, kangaroos, ostriches, and snakes.
- Many of the savanna biome animals are grazing herbivores that migrate through the region.
- They rely on their herd numbers and speed for survival, as the vast open areas provide little means of escape from quick predators.
- If the prey is too slow, it becomes dinner. If the predator is not fast enough, it goes hungry.
- Camouflage and mimicry are also very important to animals of the savanna.
- Predators often need to blend in with their environment in order to sneak up on unsuspecting prey.
- The puff adder, for example, is a snake with sandy coloring that allows it to blend in with dry grasses and shrubs.
- Prey also use the same camouflage technique as a defense mechanism to conceal themselves from animals higher up on the food chain.
- Desertsare some of the most widespread yet unexplored biomes.
- They cover about 1/3 of the earth’s surface and are found in 60 of the world’s nations.
- The largest hot desert biome (the subtropical Sahara) stretches over 3.5 million square miles or 9 million square kilometers.
- However, the Antarctica, which is a polar desert, is the largest desert overall.
- Many people assume that deserts cannot support any form of life, but they actually harbor about 4,000 different plants and animal species.
- Since desert biomes receive little precipitation per year, the conditions are very hostile for plants and animals.
- A desert biome is a collection of habitats that that develop in arid (dry) environments as a result of little rainfall (50cms per year) or no rainfall at all.
- Desert biomes are classified into four, with each having their own unique features, but have great similarity regarding living and nonliving composition.
- They include hot and dry deserts, semi-arid deserts, coastal deserts and cold deserts.
- In the midst of these 4 deserts exists numerous deserts in many areas across the globe.
- Most deserts occur far away from the coasts, in locations where moisture emanating from the oceans and seas hardly reaches.
- However, some deserts are situated on the west coast of some continents like the Atacama in Chile and Namibia in Africa, culminating in coastal fog deserts whose aridity is caused by cold ocean currents.
- The desert biomes of the world are located in six biogeographic domains including:
The Australian deserts
The Australian deserts consist of a collection of lowlands arid eco-regions in the heartland of Australia. They are hardly inhabited, and their average population density is lower than one person per square kilometer. Of all the deserts in the world, Australian deserts have the lowest human population, by far.
These desert biomes are located in Sub-Saharan Africa, including the southern fringe of the Arabian Peninsula. The biome receives a lot of pressure from humans, particularly in Madagascar and the horn of Africa.
The Indo-Malay region
The Indo-Malay region consists of 2 hot lowlands including the Indus Valley and the Thar. These deserts top the world deserts regarding human footprint.
The Neotropic deserts
Those located in South America cover an area of about 684, 000 million square miles. However, only 6 percent of this total area is protected.
The Nearctic deserts
These deserts cover an estimated area of 1.04 million square miles in North America. Due to the expansion of urban corporations like Phoenix in the U.S., their average population is relatively high.
This domain concentrates the largest range of desserts in the entire world, covering an area of a staggering 9.9 million square miles. That’s, essentially, 63% of all deserts in the world. These deserts are famous for their extreme dryness and sheer inaccessibility. The Sahara desert in Africa covers an area of about 9.9 square miles or approximately 10% of the African continent. On the flip side, the deserts located in the Central area are characterized by folded mountains, high landscape heterogeneity, as well as enclosed basins.
- Due to the availability of little moisture in the air to capture and hold on to the heat emanating from the high temperatures during the day, desert nights are typically cold.
- A combination of extreme temperature fluctuations and incredibly low levels of water makes the desert biome a very harsh land mass to live in.
- Temperatures are so extreme during the day because there is very little moisture in the atmosphere to block out the sun’s rays
- This means that the sun’s energy is absorbed on the ground surface.
- The ground surface then heats up the surrounding air.
- When night falls, the exact opposite happens.
- The heated ground, plus the hot air, radiates the heat absorbed during the day back to the atmosphere, triggering rapid drop in temperatures.
- Temperatures at night can plummet to zero degrees Celsius.
- Precipitation in hot and dry deserts is a lot different from precipitation in cold deserts.
- Hot and cold deserts typically receive very little rainfall, an average of 15 cm per year.
- Cold deserts, on the other hand, experience a lot of snow and receive rain in spring, an average of 15-26 cm, to be exact.
- Seasonal climate varies considerably in desert biomes.
- In the summer months, temperature ranges between 30 to 49 degrees Celsius. Little or zero precipitation occurs in the summer.
- Also, the rate of evaporation typically overtakes precipitation.
- In the winter months, temperatures range between 10 to 20 degrees Celsius. A lot of the precipitation takes place during these summer months.
- The very little rainfall experienced in desert biomes, as well as extreme daily temperature fluctuations, makes life difficult for plants.
- In spite of these challenges, a wide range of plants grows in this biome.
- The most common plants that thrive in desert biomes include Cacti, small shrubs, succulents, and grasses.
- To thrive in these harsh climatic conditions, desert plants have developed unique adaptations.
- Common adaptations include water storage in stems and leaves, waxy coverings on leaves, shedding leaves, all to minimize water loss.
- Some have developed long taps roots to be able to reach water tables.
- Others become dormant until the rains return.
- The cactus plant, particularly, has adapted well to the harsh climatic conditions of desert biomes such that it’s able to grow up to 20 feet or more and liver for over 200 years.
- The Giant Saguaro cactus, in particular, has managed to thrive in this harsh biome due to shallow roots, which enables it to soak up rain and dew before it evaporates. It also features a spongy interior, which has the ability to expand and hold a lot of water. Another adaptation of the cactus is that it grows slowly to save energy.
- The Mugma Tree is another plant adapted to live in desert biomes. It consists of small leaves that uniquely grow upwards and act as funnel when it rains. The funnel-like leaves direct the rain water to the base of the tree, where it’s soaked up by shallow roots. Generally, this adaptation guarantees that the tree will get a lot of water when rain falls.
- Other plants of the desert biome include Brittle Bush, Desert Ironwood, Chainfruit Cholla, Joshua Tree, Palo Verde, Jumping Cholla, Ocotillo, Pancake Prickly Pear Cactus, Soaptree Yucca and Mojave Aster.
- In spite of the harsh climatic conditions in the desert biome, many animals live here.
- These animals have developed unique adaptations to help them keep cool and use less water.
- For example, a recognizable desert animal like the Camel can get by for days without food and water due to the fat stored in its hump. It also has thick fur and underwool to protect it from the harshest of winter. Its nostrils are able to be closed to keep out blowing sand.A camel has two rows of eyelashes to shield it eyes from the sun and blowing winds and broad hooves to prevent it from sinking in the sand.
- Foxes survive here due to their burrowing and nocturnal lifestyles. This burrowing ensures they escape the intense heat during the day. They also have large ears to aid in the dissipation of excess body heat during hot days. Their thick, sandy fur helps protect them from the cold nights in the desert. The thick, sandy fur also helps reflect heat and for camouflage.
- Animals in desert biomes have also developed adaptations such as panting to minimize heat, seasonal migration, and long periods of dormancy that lasts until triggered by moisture and temperature conditions.
- Other animals in the desert biome include Bobcats, Coyotes, Javelina, Desert Tortoise, Cactus Wren, Desert Kangaroo Rat, Sonoran Desert Toad, Thorny Devil, Desert Bighorn Ship, Armadillo Lizard, Sonoran Pronghorn Antelope, and so on.
- The boreal forest is the planet’s second largest biomestretching in unbroken pattern across Europe, Asia, and North America and covers an extensive 20 million hectares.
- The forest is also referred to as Taigaor the snow forest.
- It is mainly made up of coniferous forestand trees such as larches, spruces, birches, aspens, firs, and pines.
- The tree coverage in most parts of the forest is extensive and close forming a canopy with moss undergrowth.
- But in some areas, the trees are apart with an undergrowth of lichens referred to as lichen woodland.
- The forest also has diverse climatic patterns and different species of organisms.
- As a result, it is considered one of the most important terrestrial ecosystems mainly because of its interaction with some of the earth’s scale systems, for instance, anthropogenic activities and climatic conditions
- This biome is only located in Northern Hemispheres at latitudes between 60° and 50° North.
- The forest stretches in a belt pattern across the Northern hemisphere covering approximately 100 million acres of land.
- Due to the ability of the plants found in this forest to survive in snowy or extremely cold temperatures, the location of the boreal forestcan be seen to be between the temperate deciduous forests that are located on the South Side and the Tundra located on the North.
- Northern America Forest Cover: The boreal forest in Northern America extends across the continent from the east side at Labrador to the west side at Alaska. The estimated area covered from the North side of the continent to the South is 2,000 kilometers. Canada alone is covered by 24% of the forest while America contains 11% of the boreal forest coverage.
- Europe and Asia Forest Cover: The boreal forest cover found in Europe and Asia stretches from the east side at Siberia to west at Scandinavia. The widest part of the forest measured from North to South is in Asia where it extends 3,000 kilometers. Russia alone has 58% boreal forest coverage while countries such as Sweden, Finland, and Norway have only 4%. 3% of the forest is found in China and Mongolia.
- Any region below the arctic tundra usually records extremely cold temperatures.
- Temperatures of the boreal forest found below tundra region are cold and can last for eight months between the months of October to May.
- The average temperature is estimated between -30°F and -65°F.
- Also, an average of 16-39 inches of snowfall has been recorded in the forest during winter.
- The melting of the snow between storms is slowed down by the strong winds that blow across the forest.
- During summers the temperatures change drastically and can be moderately hot. The temperature may rise to an average of 20°F to 70°F.
- The highest temperatures ever recorded is 80°F. Summers can be summarized as short, cool and moist.
- The precipitation of the boreal forest is noticed in form of snow falling in the winter and rain during the short summer period.
- The forest has areas that are permanently frozen whereas other areas are moist due to the expansive spongy moss undergrowth that soaks up the excessive water.
- Most of the rainwater and melted snow finds its way into wetlands where they are trapped and stored.
- Permafrostmay occur in some areas where the ground becomes permanently frozen preventing plant growth.
- They are common in boreal forests.
- Some areas within the forest may be wet, dry, warm, cold, windy, or shaded than other areas.
- The forest trees deposit their fallen needle-like leaves and twigs to the forest floor and after gradual decomposition, they create a habitat for many insects.
- Crevices and barks that have fallen from the trees act as a warm shelter for the small animals.
- Furthermore, the snow cover is an extremely good insulator and can provide enough warm shelter for the animals below it.
- The hanging tree branches and massive coverage of tree slow down the wind that would have caused the climatic temperatures within the forest to fall drastically.
- In the boreal forest there are six seasons as identified by a race of people living in these forests called the Cree. The seasons are spring, break-up, summer, autumn, freeze-up, and winter.
- The period in October when the trees are losing their leaves and the lakes become frozen is known as freeze-up.
- This period occurs after autumn and ends when winter starts.
- The other period is when the snow melts.
- At this time the ground looks bare. This season is called the break-up season and may last for months until all the ice in the lake has melted.
- The break up is also identified by the long days and shorter nights.
- Boreal forest is mainly made up of coniferous trees evergreens such as the spruces, pines, and larches.
- These trees maintain the green color to ensure that they utilize the minimum sunlight available and to start the process of photosynthesis early.
- The conifers have characteristic needle-like leaves that are waxy that ensure that they lose a minimal amount of water during the summer and spring periods.
- After every 2 to 3 years most of the conifers usually lose their needle-like leaves, however, some like the spruce keep theirs for approximately 8 to 9 years.
- Others lose their needle-like leaves after every year such as the Larch and Tamarack.
- Most deciduous trees fail to grow in the harsh conditions of the boreal forests. Nonetheless, some do manage to grow.
- During the autumn period, the deciduous trees lose their leaves to conserve energy during the harsh winter periods.
- The huge snow that falls during the winter period may break some of their branches.
- Deciduous trees with broad leaves are birch, poplar and aspen and those that are classified as shrubs are blueberries, willow, and alder.
- Fungi such as mushrooms are found in large quantity in the boreal forest.
- The fungi are saprophytes and get enough nutrients from the many dead branches and trees found within the forest.
- The common fungi found at the root of the conifers are the mycorrhizal fungi.
- The mycorrhizal fungi live in a symbiotic relationship with the conifers whereby they help them absorb water and mineral salts while on the other hand, they gain nutrients from the trees.
- Algae and fungus in a symbiotic interaction form lichens.
- They form an expansive undergrowth in the forest and can also be found on rocks and tree branches.
- The lichens are important for the reindeers and caribou found in the forest because these animals feed on them.
- They are part of the undergrowth in the boreal forest.
- Moss is feathery in shape and is mostly found in moist places.
- They grow well in acidic soils such as the one that is found within the forest because of the fallen coniferous needles that lower the pH of the soil.
- Moss plants such as the sphagnum absorb a lot of water from the forest ground forming a marshy ground underneath the trees.
- The mammals found in the boreal forest are herbivores such as the moose, caribou, deer, elk, voles, muskrat, beaver, hare, mice and the snowshoe.
- The herbivores are well adapted to survive in harsh environments such as hibernation.
- They are also well adapted to survive against attacks from carnivores through camouflage.
- The hunters are also well adapted to the cold weather and have important adaptation tactics that help them catch a prey as seen in wolves which hunt in groups.
- The carnivores found in the forest are the fox, lynx, marten, grizzly bear, coyote, black bear, otter, shrews, cougar, ermine and the least weasel.
- Most small mammals live in areas with microclimates.
- During winter, some mammals such as the voles and mice hibernate in burrows.
- Others make habitats that can survive for a year. The temperatures in the places that these animals dwell in are around 25° F.
- Other mammals like the bear have to eat and gain a lot of weight during the autumn period in preparation for winter.
- During winter these animals hibernate from late autumn up to spring.
- Mammals such as snowshoe hare camouflage depending on the seasons.
- During the winter period, their fur turns white while during the summer their fur coat turns brown.
- Other adaptations that are seen in mammals found in the boreal forest include fluffy feet in hares and lynx that prevent them from sinking in the snow while running.
- The birds in the forest are majorly seen around short spring and also during the summer period.
- Most birds migrate before the cold winter period, but some remain throughout the entire period.
- Birds that are found in the forest during spring period are, whooping cranes, ducks, Goshawks, great horned owls, ospreys, loons shorebirds, gulls, shorebirds, warblers, and swans.
- Some birds such as warblers travel to the forest from as far as South America while others such as the owls only frequent the biome.