A plant community , which has grown naturally without human aid refered as Natural Vegetation. It includes:
Forests,Grasslands,Shrubs and bushes
FORESTS CAN BE OF DIFFERENT FORMS AS BELOW
- Tropical deciduous forests :
Tropical desiduous are the mansoon forests found in the large part of India, Northern Australia, Central America.These regions experience seasonal changes.Trees shed their leaves in the dry season to conserve water.
- Temperate deciduous forests:
Decidous means to fall off, or shed seasonally. Just as the name implies, these decidous trees shed their leaves each fall.
Lying on the forest floor, the leaves decay. As the leaves decomposes, the nutrients contained in the leaves are absorbed by the soil. For this reason, the soils of their biome tend to be very fertile.
They are found in areas with warm, moist summers and mild winters.The three major areas of these forest type occur in the Northern hemisphere.
Mainly in North America, East Asia and Europe. Smaller areas occur in Australia and Southern South America.
Examples of tropical trees in the Northern hemisphere’s deciduous forests include Oak, Maple, beech and elm.
Birds like broad winged Hawks, Cardinals, Snowy Owls and Wood peckers are also found in this biome.
Mammals include white-tailed deer, raccoons, oppossums, porcupines and red foxes found.
Animals that live in the temperate decidous forests must be able to adapt to the changing seasons.
- Rain forests (Tropical evergreen & Temperate evergreen ):
Tropical Rainforests(Tropical Evergreen):
Tropical rainforests also called tropical Evergreen –are located near the equator between the Tropic of Cancer at the north and Tropic of Capricon in the South of the equator and close to the tropics. These regions are hot and recieve heavy rainfall throughout the year.
are warm and humid and temperature ranges from 21 to 30 degree Celsius ( 70 to 85F ).The average annual temperature of tropical rain forests is above 20C .
The Tropical rain forests receive annual precipitation amount of 60 to 160 inches ( 152 to 406 CM ) . Some rain forests in the world experiences annual rainfall amounts of almost 400 inches.
More than half of world species and animals found in rainforests .
These rainforests are rightly called the ” jewels of the earth ” and the ” World’s largest pharmacy “.
As there is no particular dry season, the trees do not shed their leaves altogether. This is the reason they are called evergreen.
Multiple storey of broad leafed evergreen tree species are in abundance. The thick canopies of the closely spaced trees do not allow the sunlight to penetrate inside the forest even in the day time.
Most nutrients that are absorbed into the soil are leached out by the abundant rainfall, which leaves the soil infertile and acidic.
Animals like Jaguar, Lemur, Leopard etc are found.The trees growing in tropical Evergreen are hardwood trees Rosewood, Ebony, Mahogany.
Amazon forests in Brazil is so enormous that it is like the Lungs of the Earth. Anacondas, one of the World’s largest snakes is found in the tropical rainforests.
Temperate Rainforests (
Temperate rainforests account for around one-quarter of the World’s forest in a temperate region.
These rainforests spread much further north and south than their tropical counterpart.
They exist in North America, Europe, South America and also in Australia and New Zealand.
- Mediterranean Vegetation :
This type of vegetation occur between 30 and 40 degrees northern and southern latitudes on the westward sides of continents and include five regions. These are the Mediterranean, south central and southwestern Australia, the fynbos of southern Africa, the Chilean Matorral, and the Mediterranean ecoregions of California with scrubland vegetation (chaparral).
The Mediterranean forests have lost much of their natural condition as a result of excessive logging, fire, and overgrazing by livestock, especially goats. Forests are especially threatened at the boundaries of their natural distribution, such as the forest–steppe regions of southern Ukraine and Russia or in the Mediterranean Basin.
Most of the Central Europe’s alluvial forests along all major river courses have virtually disappeared. Airborne pollution (mostly in the form of acid deposition and photochemical smog) is also a major cause of damage to forest ecosystems in Europe, particularly in Central and eastern Europe. First reported in the Black and Bavarian forests of Germany in the early 1970s, damage from air pollution may now be detected in a quarter of all European trees.
Although boreal and Mediterranean forestsare different in many ways, management and restoration strategies in both regions have begun to focus on ecological heterogeneity as a way to increase ecosystem resilience and sustain native biodiversity.
For terrestrial ecosystems, the most basic form of heterogeneity is in the soil. Soils are naturally variable at all spatial scales, from soil micro-structure to the landscape. This variability plays a major role in driving habitat diversity, from the soil biota, to vegetation structure and composition at local and regional scales, to landscape-scale patterns.
- Coniferous Forests :
Coniferous forest regions have cold, long, snowy winters, and warm, humid summers; well-defined seasons, at least four to six frost-free months. Example: Lahti, Finland.
The coniferous forest is sandwiched in between the tundra to the north and the deciduous forest to the south. One type of coniferous forest, the northern boreal forest, is found in 50° to 60°N latitudes. Another type, temperate coniferous forests, grows in lower latitudes of North America, Europe, and Asia, in the high elevations of mountains. Coniferous forests consist mostly of conifers, which are trees that grow needles instead of leaves and cones instead of flowers. Conifers tend to be evergreen—they bear needles all year long. These adaptations help conifers survive in areas that are very cold or dry. Some of the more common conifers are spruces, pines, and firs.
Annual rainfall in coniferous forests varies from 300 to 900 mm annually, with some temperate coniferous forests receiving up to 2,000 mm/ year (79 in/year). The amount of precipitation depends on the forest location. In the northern boreal forests, the winters are long, cold and dry, while the short summers are moderately warm and moist. In the lower latitudes, precipitation is more evenly distributed throughout the year.
Temperate Coniferous forests cover the highest percentage of forest literacy rate in the world. Temperate coniferous forest is a terrestrial biome found in temperate regions of the world with warm summers and cool winters and adequate rainfall to sustain a forest.
- Tundra :
A vast, flat, treeless Arctic region of Europe, Asia and North America in which the subsoil is permanently frozen.Devoid of tree except standard shrub in the southern part of Tundra biome.Grand flora like litchen, mosses and sedges.
Animals like reindeer, arctic fox, polar bear, snowy owk, arctic hare.Reptiles and amphibians are almost absent.Extremely cold climate, low biotic diversity.Limitation of drainage.
Short season of growth and reproduction.Energy and nutrients in the form of dead organic material.Tropical rain forests.
- Taiga :
The Swampy coniferous forest of high northern latitudes, especially that between the tundra and steppes of Siberia.Northern Europe, Asia and North America, moderate temperature than tundra also known as boreal forest.
The dominating vegetation is coniferous evergreen mostly spruce with some pine and firs.The fauna consists of small seed eating birds, hawks, fur bearing carnivores, little minks, elks, puma, siberian tiger, wolverine, wolves etc.
- Savannah :
Tropical region savannah is most extensive in Africa.Grasses with scattered tree and five resisting throny shrub. The tropical Savannah is a biome characterized by tall grasses and occassional trees.
The fauna include a great diversity of grazzers and browers such as antelope, buffalo, Zebra, elephant, lions, cheetah. Savannas can result from either climate, soil conditions, animal behaviour or agricultural practices, which limit the occurances of trees.
Humans create Savannah by burning the grasslands and felling the trees in order to plant crops. Large animals such as elephants can turn a forest into a Savannah by stripping the bark from the trees , knocking over trees and tramping on tree seedlings.
- Grassland :
North America, Ukraine, have temperate conditions with rather low rainfall.Grasses dominated the vegetation, fauna like cattle, rodent, wolves and rich and diverse array of ground nesting birds.
- Desert :
Very low rainfall, days are hot but nights are cold.The flora is drought resistance vegetation such as cactus, sagebrush, fauna reptiles, birds, mammals etc.