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GEO12 LG # 13

INTRODUCTION

Biomes are the major regional groupings of plants and animals discernible on a global scale. Their distribution patterns are strongly related to regional climate patterns and identified according to the climax vegetation type. However, a biome is composed not only of the climax vegetation, but also of associated successional communities, persistent subclimax communities, fauna, and soils. The biome concept embraces the idea of community, of interaction among vegetation, animal populations, and soil. A biome (also called a biotic area) may be defined as a major region of distinctive plant and animal groups well adapted to the physical environment of its distribution area.

EVALUATION

RESOURCES

1.      Planet Earth: A Physical Geography, Chapter 11 Natural Vegetation and Soil Systems  pp.218-225

2.      Understanding Our Environment, Chapter 4, World Ecosystems, pages 41-47

3.      Understanding Our Environment, Chapter 8, Land, Tropical Rain Forests, pages 123-126

4.      Understanding Our Environment, Chapter 8, Land, Northern Coniferous Forests, pages 126-130

5.      Understanding Our Environment, Chapter 5, Endangered Species, pages 58-69

6.      Understanding Our Environment, Chapter 12, Rural Management & Conservation, pages 187-199  

Good Websites:

http://www.cln.org/themes/endangered.html Endangered Species Theme Page

 http://www.cln.org/themes/tropical_rainforests.html Tropical Rainforests Theme Page  

http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/intro.html Covers Biomes in Detail

LEARNING GUIDE OUTCOMES

 Completion of the activities in this Learning Guide you will enable you to:

1.      Investigate the nature of the earth's major biomes

2.      Analyze how and why the needs of humans sometimes conflict with the survival needs of animal species.

3.      Learn about an animal species that is nearing extinction, including the causes of its extinction and actions undertaken towards the conservation of this species.

 Learning Activity 1: Mapping Biomes (25 marks)   Back to evaluation

On a 8.5”X11” (216 X 279mm) sheet of blank paper, using the format provided below:

·        Make a copy of the Biome map on page 41 of your text Understanding Our Environment

·        Include the title: Six Major Biomes of the World

·        Colour and provide a key for each of the six biomes

·        Construct and complete the table 

 Learning Activity 3: Endangered Species Research (25 marks) Back to evaluation

 Choose ONE of the following only

1.      Select an animal species that is nearing extinction

2.      Suggested species: Vancouver Island marmot, African elephant, short-tailed albatross, aye-aye, coral reef, dwarf crocodile, Philippine eagle, Indian elephant, black-footed ferret, mountain gorilla, kakapo, komodo dragon, black lemur, hairy-eared dwarf lemur, hyacinth macaw, manatee, numbat, orangutan, giant otter, Humboldt penguin, Indian python, black rhinoceros, Mediterranean monk seal, Malaysian sun bear, golden lion tamarin, tiger, Monteverde golden toad, leatherback turtle, golden-cheeked warbler, gray whale, Mariana fruit bat, woodland caribou, San Joaquin kit fox, bighorn sheep, California condor, American peregrine falcon, marbled murrelet, northern spotted owl, brown pelican.

 Using available resource materials, research your animal, answering the following questions:

1.      What is this animal's natural habitat, and where in the world can this habitat be found?

2.      What are this animal's physical features, and how do they enhance its ability to survive in its natural habitat?

3.      What foods does this animal eat?

4.      What are the causes of this animal's endangerment?

5.      What actions have been taken towards the conservation of this species?

6.      Write a position statement that explains the importance of preserving this species

Reference Notes : Source: Complimentary Readings, Geography 12 (BC Ministry of Education)

BIOMES

Although people sometimes study climate phenomena in isolation, an examination of the interrelationships among climate, vegetation, soils and other lifeforms within and across biomes is more meaningful. A comparison of biomes is important in understanding adaptations to the environment and modifications to the environment that human activity creates.  

Sometimes called a bio-geoclimatic zone, a biome is an extensive terrestrial (land-based) ecological community with characteristic vegetation and animal species (flora and fauna) maintained under particular climatic conditions. A number of differing, specific ecosystems can exist within a single biome. For example, Mediterranean, sclerophyll, and chaparral are all types of deciduous forest existing in North and South America, Europe, Africa, Asia, and Australia; within the biome of coniferous forest in BC, ecosystems of bog, marshland, alpine meadow, glacier, and various forest types can be found.

CHARACTERISTIC FLORA OF BIOMES

Tropical Rainforest

Tropical rainforests are the most productive and the most diverse of all the world's biomes. More species of plants are found in the tropical rain- forest than in all other biomes combined. A single hectare of forest may contain over 300 different species of trees.  

In tropical rainforests, precipitation is almost a daily event. The air is constantly humid, and the hot temperatures remain virtually unchanged from day to night or from season to season. The dominant vegetation is hardwood broadleaf evergreens-such as ebony, ironwood, and mahogany--existing in a layered structure caused by competing plants struggling to reach their required amount of light. In a dense tropical rainforest, a closed canopy of trees creates deep shade; consequently there is little ground vegetation. Climbing vines use tree trunks to grow upward into the sunlit areas. The hot, wet conditions mean that decomposition is so fast that the soils require continuous leaf fall to maintain a thin surface layer of humus. Most trees in the rainforest have shallow roots to top into the thin layer of nutrients.  

Tropical rainforests are found in Central and South America, Africa, and the south Asian archipelago that includes Indonesia, the Philippines, and New Guinea. There is a complex system of interaction between plant and animal species in tropical rainforests: many species of insects feed only on particular plant species. This interdependence compounds the negative effects of rainforest destruction.  

Temperate Deciduous Forest Temperate deciduous forests broadleaf are found in latitudes where winters are mild but still cold enough to restrict growth and precipitation is over 750 mm per year. Trees are deciduous, which means they shed their leaves in autumn (for the most part). Many varieties exist, including the birch and maple forests of the St. Lawrence Valley and the oak and hickory forests of the Appalachians. Other deciduous species include beech, walnut, poplar, elm, ash, sycamore, and chestnut. Where soil and climate conditions are less favourable, coniferous trees such as pine and spruce are often mixed with deciduous.  

The leaf litter from deciduous trees provides a richer source of humus than in coniferous forests; due to this and the lack of glaciation, soils are usually quite rich and deep, and there are sufficient basic nutrients for smaller plant growth. Many flowering plants bloom early in the year before the taller trees have developed their full foliage.  

Since the Middle Ages, the demand for timber (for construction and shipbuilding) has meant that the broadleaf forests of the world have been largely cut down. Most land that was originally under deciduous forest in Europe and North America is now used for commercial forming or has been urbanized.  

Coniferous Forest also known as taiga or boreal forest, this biome stretches in an almost unbroken zone of coniferous forest across the subarctic regions of North America, Asia, and Europe. These forests are dominated by a relatively limited number of conifer species such as cedar, spruce, pine, larch, and fir, which have developed distinctive adaptations to the short summers and long, cold, snowy winters. Their shape helps them to shed snow, and their waxy, needle-like leaves protect against the drying effects of cold air. Most conifers are evergreen, making best use of the short growing season. They have hard cones to protect their seeds from birds, animals, and harsh weather conditions, allowing time for the seeds to germinate in the spring. They can survive the tough climate, since energy is not wasted in annual leaf loss and replacement as happens with deciduous species.  

Close spacing of trees in a coniferous forest means that little sunlight penetrates to ground level. Therefore, lower levels of vegetation are sparse-primarily mosses and lichens-or non-existent.  

On the West Coast of North America, there is sufficient rainfall for coniferous forests to develop as temperate rain forests, characterized by conifers such as the Douglas fir and redwoods. Here trees can reach as high as 95 m. These giant trees form the basis of British Columbia's coastal forest industry.

Deserts

There are three types of deserts

Ø      Cold deserts have hot summers and cold, even snowy, winters. There are cold deserts in Oregon, Utah, and Nevada. The Gobi Desert of Central Asia is a cold desert.  

Ø      Warm or temperate deserts experience warm to hot temperatures all year round. The desert areas of California and Arizona are temperate deserts.  

Ø      Hot or tropical deserts have high temperatures all year round. There is very little vegetation. The Sahara is an example of a hot desert.  

Only a few deserts like the Sahara consist of barren sand dunes. The rest have some form of vegetation that has adapted to the extreme aridity. The cacti found in deserts of the Western Hemisphere collect water from a wide area with their extremely shallow root system; they can store water in their fleshy stems until the next rain. The thorny bushes and shrubs found in deserts often have taproots that run deep into the ground in search of water. Desert plants are sometimes called xerophytes, meaning 'adopted to drought conditions."  

Savanna  

Also called tropical grasslands, savannas are found to the north and south of tropical rainforests. Savannas typically receive high precipitation in one or two short seasons and virtually no precipitation in others. Characteristic vegetation of savannas includes coarse grasses that grow in the wet season then remain dormant for the rest of the year. Although grasslands have the potential to return organic matter back to the soil, the rate of decomposition is reduced during the drought season. Frequent fires result in the dominance of grass and few trees. Those trees that do grow have flattened tops thorn-like leaves, and thick, rough bark. Savannas exist primarily in Africa, but can also be found in South America and Australia.  

Temperate Grasslands (Steppe and Prairie)  

The temperate grasslands are primarily found in the interior and rainshadow areas of North America and Eurasia, areas that are too dry or too frequently burned to permit the growth of forests. Temperate grasslands are also found in the southern continents, such as the Pampas of South America, the veldt of South Africa, and the Canterbury Plains of New Zealand; these southern temperate grasslands exhibit less extreme climatic conditions than those of the northern continents.  

Mixed short grasses with few trees characterize vegetation in the temperate grasslands. These grasses grow quickly in early summer, and produce seeds during the short, rainy periods. In dry years, seeds can lie dormant until moisture arrives. Grasses have deep roots that form tightly knit sods, posing a further restriction to tree growth. If overgrazed, xerophytic shrubs such as the prickly pear often invade these grasses. Some species of shrubs and trees (e.g., willow) will grow along watercourses.  

Tundra  

Tundra is found primarily in the regions north of the coniferous forest, where the climate is too cold and annual precipitation is too low for tree growth. Tundra is characterized by permafrost---ground with a permanently frozen layer beneath its surface. The short summers are worm enough to melt the top layer of ground, which forms the active layer. Plants therefore stay close to the ground and grow slowly to take advantage of what warmth can be absorbed from the sun. Characteristic shallow root vegetation includes grosses, lichens, mosses, annual flowering plants, and dwarf shrubs. Much of the tundra is waterlogged in the summer, since the permafrost prevents drainage.  

There are fewer species of plants in the tundra than in any other biome. Only those plants that can survive the harsh weather, expansion, and contraction of the soil as it freezes and thaws will persist. It takes a long time for vegetation destroyed by human interference to grow back to its undisturbed state.  

CHARACTERISTIC FAUNA OF BIOMES

Tropical Rainforest

Tropical rainforests have great biodiversity: there are more different kinds of organisms in a tropical rainforest than in any other biome. In a tropical forest, animal life is so varied that you could find more species on a single tree than you might find in an entire coniferous forest. However, in a rainforest the number of individuals of any one species is small. Most of the life is found in the forest canopy, not on the forest floor. Up in the trees there are butterflies, birds, monkeys, lemurs, snakes, and frogs.  

Animal species in the tropical rainforests play an interdependent role with plant species in maintaining the balance of life. Flowers in the rainforest, for example, may be pollinated by such diverse species as insects, bats, mice, and hummingbirds.  

Temperate Deciduous Forest

Deer are the most common herbivore in North American deciduous forests. As well, the forest is home to porcupines, skunks, raccoons, opossums, beavers, and numerous small rodents, such as squirrels and shrews. The predators (now much reduced in numbers) include wolves, bobcats, foxes, and cougars. Songbirds, raptors (hawks and owls), reptiles, and amphibians also inhabit the forest.

Coniferous Forest

The wildlife of the temperate evergreen forest is similar to that of the temperate deciduous forest.

In colder coniferous forests (sometimes called boreal forest or taiga), where winters are long and extremely cold, there are fewer species. There are large herbivores: moose, caribou, elk, and mule deer. Smaller herbivores include hare, squirrel, and other small rodents. Predators include the timber wolf, lynx, bear, marten, wolverine, and weasel.  

Desert

Most desert animals are small and nocturnal; both these adaptations enable them to conserve moisture. Rodents, lizards, snakes, toads and other reptiles, owls, eagles, vultures, small birds, and insects are typical wild species of the desert. The scaly skin of reptiles and the hard exterior of insects both serve to prevent evaporation. Some desert creatures drink the morning dew, others survive on moisture they get from their food.  

Savanna

When undisturbed, the tropical savanna supports large herds of grazing animals, such as the gazelle, zebra, elephant, and wildebeest of Africa, and the kangaroo of Australia. Grazing herds in turn support predators such as lions and jackals.  

Temperate Grassland (Steppe and Prairie)

Before the grasslands of North America were turned to cultivation, they supported herds of large herbivores, such as bison, elk, and pronghorn antelope. These wild species survive only in parks now. There were also predators such as coyote, cougar, wolf, and bear. Numerous small herbivores are still found in undisturbed grassland: jackrabbit, pocket gopher, and prairie dog. Before the settlers reduced their numbers, the prairie dogs contributed to the fertility of the prairies: the tunnels of their colonies aerated the soil and their droppings enriched it.  

Tundra

Most animals that live year round on the tundra burrow under the snow: lemmings, for example, can do this. The large herbivores on the tundra (muskox, caribou, and reindeer) are not year round residents, but migrate south in fall. Many tundra animals, such as the snowy owl, ptarmigan, and ermine, have white coats to camouflage them from predators during the snowy winter. In the summer, there are large flocks of waterfowl and other birds that migrate to the tundra to nest; they feed on the swarms of insects that breed in the bogs and shallow ponds.  

CLIMATE AND VEGETATION OF NORTH AMERICA

Vegetation Zone: tropical rainforest or tropical moist forest

Characteristics of Vegetation: lush forest with closed canopy; many different species; evergreen and deciduous

Climate: hot, humid; in monsoon forest, wet and dry season

Vegetation Zone: savanna

Characteristics of Vegetation: tropical grasslands with some trees; plants show adaptation to long dry season

Climate: hot, with wet and dry seasons  

Vegetation Zone: desert  

Characteristics of Vegetation: sparse vegetation; plants such as yucca, Joshua tree that are adapted to hot, dry climate; after rainfall, there may be brief, lush carpet of flowers

Climate: hot, dry (cold deserts have cold, even snowy, winters)  

Vegetation Zone: steppe and prairie grasslands

Characteristics of Vegetation: high and low grasses mixed with small bushes and shrubs and occasional trees

Climate: hot dry summers, cold snowy winters  

Vegetation Zone: temperate deciduous forests  

Characteristics of Vegetation: deciduous trees such as ash, maple, birch, oak, beech; also shrubs and flowers  

Climate: abundant precipitation, moderate temperatures with seasonal variation  

Vegetation Zone: coniferous forest  

Characteristics of Vegetation: coniferous trees such as fir, spruce, pine, cedar

 Climate: mild, moist  

Vegetation Zone: tundra

Characteristics of Vegetation: mosses and lichens; occasional stunted trees  

Climate: cold, moist

REMINDER CHECKLIST

You are ready to proceed to the next Learning Guide when you have completed the following activities:

·        Submitted required assignment(s);

·        Attended Seminar

·        No test or quiz on this guide

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