On Biomes

On Biomes:

There are no two areas, or even two things, on Earth that are exactly alike. The stripes on every zebra’s back, the pattern of a tongue (i.e. tongue print), thumbprints and many other examples can be given of things on earth that are distinctly unique in each respective individual. Even identical twins are not, in the truest sense of the word “identical”. The Earth is filled with uniqueness and fueled by diversity; and within these, its beauty lies. Despite this fact, there are things that are similar. Not truly identical, but similar. A good example of things that are similar would be that of biomes. Biomes are areas on the earth that have similar climatic conditions, and similar flora, fauna and other life forms. The word “biome” is a concept developed by North American environmental scientists (its European equivalent is “Major Life Zones”).

 

Wikipedia defines biomes as “climatically and geographically defined areas of similar climatic conditions such as communities of plants, animals, and soil organisms.”

There are a number of biomes in the world, and each consists of a number of ecosystems.

A biome’s plant life, climate, and location are what characterize it. Moreover, the factors that distinguish a biome from another are: plant structure (e.g. trees, shrubs, grasses); leaf types (e.g. broad leaf or needle leaf); plant spacing (e.g. woodland, savanna, forest); and climate. The Earth’s biomes are: tundra, boreal forests, grasslands, chaparral, tropical rain forests, savannas, deserts, deciduous forests, taiga, and hydro-related biomes. In the paper that follows, I have analyzed the above-mentioned biomes in consideration to their temperature, rainfall, vegetation, altitude, productivity, and other factors that distinguish a biome from another.

 

The tundra biome: Tundra, as a word, originates from the Finnish word tunturi, which means “treeless plain.” Characteristically, tundra has extremely low temperatures and is actually the coldest of all the biomes. Other characteristics that define this biome are: its “frost-molded” landscapes (i.e. the landforms are patterned by ice), its short growing seasons, its low-soil nutrient content, and its very low levels of annual precipitation. Tundra is divided into two: arctic tundra, and alpine tundra. The arctic tundra encircles the North Pole, and is famed for its cold desert-like conditions (sometimes referred to as cold-deserts). Arctic tundra has an average winter temperature of -34º C, although in summer it ranges from 3 º to 12 º C. This summer temperature range is what allows this biome to sustain life. Many people think that the weather in the whole of the Arctic is unlivable, in that it is extremely cold that no form of life can exist, but the arctic boasts a huge range of life forms. Actually, the Arctic ecosystem is alive and kicking, packed with forms of life at virtually all trophic levels. In terms of both flora and fauna, the Arctic is blessed with a huge variety e.g.: low shrubs, sedges, reindeer mosses, liverworts and grasses. Also, there are four hundred varieties of flowers and two varieties of lichen (crustose and foliose). There are about 1,700 kinds of plants in the arctic and sub-arctic combined. All these plants are adapted, in complex and simple ways, to the extreme climatic conditions of the Arctic tundra. In terms of fauna, there are lemmings, caribou, arctic hares, arctic foxes, wolves, mosquitoes, blackflies, migratory birds (e.g. terns, falcons) and the very famous polar bears. There is also a huge assortment of fish species: cod, salmon, trout and flatfish. Commenting on the survival-techniques of these animals, www.cotf.edu, an educational website records:

“[These] animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer. Animals such as mammals and birds also have additional insulation from fat. Many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually oscillates.”

The other type of tundra – the Alpine tundra – is found on mountains throughout the world. This biome is found on very high altitudes where trees cannot grow, and where the nighttime temperatures are usually below 0ºC. Mount Kilimanjaro, the highest mountain in Africa, highest freestanding Mountain in the world and most beautiful mountain in the world, has a good example of alpine tundra. The mountain is beautifully arrayed with flowering alpine tundra (around Gilman’s point) and has the typical characteristics of this biome. Unlike the arctic tundra, the soil in the alpine is well drained, though the plants are interestingly similar to those of the arctic tundra.

 

The desert biome: The main characteristic of deserts is that they are dry. Although the rate of annual precipitation differs depending on geographical location, the average range of annual precipitation is from half an inch to as much as fifteen inches. Rain is virtually the only form of precipitation, and is usually confined to very small areas. As can be judged, rainfall is infrequent and difficult to predict. It is very hard to tell when and/or where it is going to rain in a desert. The Sahara desert is currently the world’s largest desert, and the fastest spreading one too, but it is not necessarily the driest. The educational website www.cotf.edu records that “At times in the Atacama desert in Chile, years have passed with no measurable rainfall at all. However, that is not generally the case.” Deserts can be classified into hot deserts, and cold deserts. Most deserts are hot deserts (e.g. the Australian desert, The Sahara, Namib, Kalahari, Atacama), and some, like the Gobi, are cold deserts. Due to their dryness, deserts have huge daily temperature variations (very hot days, and very cold nights). They have extremely high temperatures during the day because there is very little moisture in the air to block the Sun’s rays from reaching the desert surface. At night, after the sun has gone down, the heat absorbed during the day quickly escapes back into space, leaving the place in extreme coldness. These extreme variations make survival in the desert very difficult. Moreover, this implies very low productivity except in oases, which act as natural reservoirs of the few desert rains, and therefore have higher productivity than the other parts. Desert plants include cacti, and other xerophytes; also include dates, palm trees, grasses, and flowers in oases.

 

The taiga biome/boreal forests: Taiga is a biome characterized by coniferous forests. The taiga is found throughout the high northern latitudes, between the tundra, and the steppes. Actually, the taiga is the world's largest terrestrial biome. It covers most of inland Alaska, Canada, Sweden, Finland, inland Norway and Russia (especially Siberia), as well as other parts of the United States (Northern Minnesota, Michigan, Upstate New York, New Hampshire, and Maine). In Asia: northern Kazakhstan and Japan. Boreal forest is the term used to refer to the southern part of this biome, while "taiga" is used to describe the more barren northern areas of the Arctic tree line. The taiga, due to its extensiveness, has high variations of annual temperature. Generally, temperatures vary from −50 °C to 30 °C (-58°F to 86°F) throughout the whole year, with eight or more months of temperatures averaging below 10 °C (50°F). Seasons are divided into short, moist, and moderately warm summers and long, cold, and dry winters. The length of the growing season in boreal forests is 130 days. Due to the very low temperatures that are characteristic of this biome, precipitation is primarily in the form of snow, 40-100 cm annually. The plants that can be found in taigas are mostly cold-tolerant evergreen conifers with needle-like leaves, such as pine, fir, and spruce. The adaptation of evergreen needles limits the water lost due to transpiration and their dark green color increases their absorption of sunlight. It is important to note that the ground freezes during the winter months and plant roots are unable to absorb water, so desiccation (i.e. loss of moisture) can be a severe problem in late winter for evergreens. Fauna include woodpeckers, hawks, moose, bear, weasel, lynx, fox, wolf, deer, hares, chipmunks, shrews, and bats. Quoting Wikipedia, the free online encyclopedia, “Some of the larger mammals, such as bears, eat during the summer in order to gain weight and then go into hibernation during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold.” Soils in the taiga are thin, acidic and very poor in nutrients; this means that the productivity of the taiga is relatively very low.

 

Grasslands (Savanna; Steppes; Temperate Grasslands): As the name suggests, grasslands are characterized as lands dominated by grasses rather than large shrubs or trees. They are categorized mainly into: temperate grasslands, and tropical grasslands (savanna). Savanna is grassland with scattered individual trees. When one thinks of the African wild, the picture that comes to mind is that of endless plains of dried grass, scattered acacias, baobabs and other trees, and beautiful Serengeti-like animals – an authentic picture of the Savanna. Almost half of the surface of Africa is covered in savanna (about five million square miles, virtually all of East and Central Africa). Other parts of the world with savanna are Australia, India and South America. Savannas are always found in warm or hot climates with annual rainfalls of around 50.8 to 127 cm. Most savannas would be tropical rain forests if the rain was evenly distributed throughout the year; but in savannas, rainfall is concentrated in six or eight moths of the year, followed by an extensive period of drought which limits the plant growth. Savanna is not offered with a variety of seasons: it only has rainy (wet) and dry seasons. Generally, savannas receive an average annual rainfall of 76.2-101.6 cm (30-40 inches). However, certain savannas can receive as little as 15.24 cm (6 inches) or as much as 25.4 cm (10 inches) of rain a year. In light of productivity: savanna soils are porous hence a rapid drainage of water and nutrients. The soil has only a thin layer of humus, and this thin layer is what provides the vegetation with nutrients. The predominant vegetation is obviously grass, and what is called forbs (small broad-leaved plants that grow with grasses.) In drier savannas like the Serengeti plains or the Laikipia plateau in Kenya, for example, the dominant grasses are star grasses, Rhodes grass, lemon grass and red-oat grass. According to some researchers on their university website: www.ucmp.berkeley.edu “One type of savanna common in southwestern Kenya, Tanzania, and Uganda, known as grouped-tree grassland, has trees growing only on termite mounds — the intervening soil being too thin or poorly drained to support the growth of trees at all. Frequent fires and large grazing mammals kill seedlings, thus keeping the density of trees and shrubs low.” Antelopes, gazelles, dik-dik, giraffes, zebras, buffaloes, lions, cheetahs, hyenas, mice, moles, gophers, snakes, worms, termites, beetles, and many other “African” animals, elephants and kangaroos (in the Australian savannas) are examples of the richness of the savanna in terms of fauna. Environmental concerns pertaining to savannas are mainly poaching, overgrazing, and bush-clearing for agriculture and settlement. Daystar’s Athi River Campus is set in a typical savanna, therefore what is explained above is characteristically what we experience everyday. The main differences of savanna and temperate grasslands are summed up in the words that follow: In temperate grasslands “temperatures vary more from summer to winter, and the amount of rainfall is less in temperate grasslands than in savannas. The major manifestations are the veldts of South Africa, the puszta of Hungary, the pampas of Argentina and Uruguay, the steppes of the former Soviet Union, and the plains and prairies of central North America. Temperate grasslands have hot summers and cold winters. Rainfall is moderate. The amount of annual rainfall influences the height of grassland vegetation, with taller grasses in wetter regions. As in the savanna, seasonal drought and occasional fires are very important to biodiversity. However, their effects aren't as dramatic in temperate grasslands as they are in savannas. The soil of the temperate grasslands is deep and dark, with fertile upper layers. It is nutrient-rich from the growth and decay of deep, many-branched grass roots. The rotted roots hold the soil together and provide a food source for living plants.”

 

The forest biome: A forest is simply a large dense growth of trees. Therefore, forest biomes are biological communities that are dominated by trees and other woody vegetation (Spurr and Barnes, 1980). There are three major types of forests: tropical rainforests, temperate forests, and boreal forests (which have already been discussed under taiga). Forests occupy approximately one-third of Earth’s land area, they account for about 70% of the carbon present in living things. This shows the tremendous significance of this biome to life on earth. However, as Berkeley records, “…forests are becoming major casualties of civilization as human populations have increased over the past several thousand years, bringing deforestation, pollution, and industrial usage problems to this important biome.” Tropical forests have a greater diversity of species than all other biomes combined. Rainforests are characterized by high rainfall. This often results in poor soils due to leaching of soluble nutrients. The soils are, as stated, nutrient-poor and acidic; and decomposition is very quick. The average temperature range is around 20° - 25°C and varies little throughout the year. Flora is highly diverse: one square kilometer may contain as many as 100 different tree species. Trees are 25-35 m tall, with buttressed trunks and shallow roots, mostly evergreen, with large dark green leaves. Plants such as orchids, bromeliads, vines (lianas), ferns, mosses, and palms are present in tropical forests. Fauna include numerous birds, bats, small mammals, and insects. The rainforests are further classified according to the length of the dry season into: evergreen rainforests, seasonal rainforests, semi-evergreen rainforests, and moist/dry (monsoon) rainforests. Tropical forests are on the threshold of destruction, and are faced with numerous environmental problems. The fact that over half of these tropical forests have been destroyed only adds upon this truth. Temperate Forests are different from tropical forests especially in their location, and, therefore, the climate. While the tropical forests are found around the equator, temperate forests occur in eastern North America, northeastern Asia, and western and central Europe. Well-defined seasons with a distinct winter characterize this forest biome. Moderate climate and a growing season of 140-200 days during 4-6 frost-free months distinguish temperate forests from tropical forests. The temperature obviously depends on the season but generally ranges between -30°C and 30°C. Precipitation is evenly distributed throughout the year and ranges between 75-150 cm. The productivity of the soils in these forests is high because the soil is very fertile and constantly enriched with natural decaying litter. Most of the fauna in these forests is trees, obviously, and it is mostly hardwood trees like oak, hickory, beech, hemlock, maple, basswood, cottonwood, elm, willow, and spring-flowering herbs. Fauna is mainly “forest” animals like squirrels, rabbits, skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.

 

Chaparral: this is not exactly a biome, but a shrub land or heath land community that is primarily found in California (USA) and in the northern portion of Lower California, Mexico. The word chaparral is coined from the Spanish chaparro, meaning dwarf-like evergreen oak. A typical chaparral plant community consists of densely-growing evergreen scrub oaks and other drought-resistant shrubs. It often grows so densely that it is all but impenetrable to large animals and humans. This, and its generally arid condition, makes it notoriously prone to wildfires. It is commonly believed that chaparral plant species are adapted to fire, because of the many times that raging fires burn up huge parts of their communities, and the plants remaining intact. Although many chaparral plant species require some fire cue (heat, smoke, or charred wood) for germination, chaparral plants are not "adapted" to fire per se. It is shaped by a Mediterranean climate (mild, wet winters and hot dry summers) and wildfire, as stated above. Similar plant communities are found in the five other Mediterranean climate regions around the world. The University of California at Berkeley’s site www.ucmp.berkeley.edu records the following plant species as native to chaparral communities: Ceanothus, Chamise, Redshanks, Chaparral Pea, Scrub oak, California Coffeeberry, Islay or Hollyleaf Cherry, Silk-tassel bush, Laurel sumac, Manzanita, Mountain mahogany, Toyon, and Yucca.

 

After identifying the Earth’s major life zones, and seeing their characteristics together with the many, mostly negative, impacts that man has upon them we are at a better position to move forward to an improved future with positive action. There has always been, and will always be, a great need to preserve what is placed in our hands. To conserve what is around us, and that which is within us. For the most part humankind has been preoccupied with a bulk of wants that it has created for itself; and it has gone out, exploiting and depleting Earth’s resources along the way, in attempts to satisfy these artificial wants. For long we have been pushed around in an endless cycle of wants, wants, and more wants. An “invisible hand” of greed and self-interest has driven us round and round in this infinite cycle of endless wanting. Nevertheless, my belief is swathed in Mahatma Gandhi’s words, “the earth provides enough to satisfy every person’s need but not every person’s greed… Civilization, in the real sense of the term, consists not in the multiplication of our wants but in the deliberate and voluntary reduction of wants.” The question is: Will people ever stop wanting? Obviously, No! Wants are almost innate impulses. But, can we not “deliberately” reduce our wants? Yes, we can! Yes, we should! But how?

 

By learning about, and from, our environment we can be better stewards. By increasing awareness of the problems we cause ourselves by destroying our environment, we shall be provoked to think on how to curb further damage to the environment. We hold the keys to a brighter and greener tomorrow. Now, let us not merely hold them. Let us take these keys, put them into the doors of opportunity by thinking originally on how to solve the problems we caused; and let us turn the keys by acting according to the numerous positive ideas generated on environmental conservation at all levels. Let us move into this bright future that lies ahead, by engaging in a quest for positive alternative lifestyles. Again, by thinking originally, like children – whose creativity and sense of wonder are still intact – as we search for alternative sources of energy, or better still, alternative ways of using those that we already have. I call upon continual and cooperative movement towards treading as lightly as possible on our beautiful planet; in the words of G. Tyler Miller, “learning to live simply so that others, human or nonhuman, may simply live.” Many people have been discouraged by the expenses of conserving the environment, and so have backed down from their attempts. Conversely, the problems we face should not pull us out of this noble cause but rather push us further into it. While considering the costs of our struggle we should keep our eyes on the rewards our efforts carry. The words of Gaylord Nelson offer a witty conclusion, “When it is asked how much it will cost to protect the environment, one more question should be asked: How much will it cost our civilization if we do not?”