Tundra
Tundra occurs close to the North Pole, above 65 drees N. The South Pole is largely surrounded by the ice and the seas of the Antarctica, and so there are very little area with plants. Tundra is the coldest biome, and precipitation and evaporation are minimal.
Even with the little precipitation, the lack of evaporation and drainage means the ground is waterlogged and permanent ice occurs below a few centimetres of soils.
The plants are mostly;
- Mosses
- Linches
- Herbs
- And low shrubs.
(Grasses and sedges occur in drier places as do other flowering plants)
Plant diversity is low and most plants are small.
Alpine
The Alpine Biome is similar to Tundra but lacks permanent ice below the soil, and the temperature very more widely. Alpine areas occur throughout the world, often at about 10,000 feet at lower latitudes, but always just below the snow line. Because of their altitude, these are widely cold places. The thin atmosphere provides only limited protection from UV radiation.
Many Alpine plants are therefore low and slow growing.
Taiga
These cool, moist forests occur from 50 to 60 degrees N.
The short summer bring rain, and most of the plants are conifers like;
- Spruce
- Fir
- larch
- and pine
(With an understory dominated by shrubs in the blueberry and rose families.)
The soils are deep with accumulated organic matter because of the low temperature result in slow decomposition but they are acidic and poor in nutrients.
Temperature Coniferous Forest
Two Broad areas of temperature conifers forest occur below 50 degree N in North America, Northern Japan and parts of Europe and the continental Asia.
Along the Pacific coast of the U.S, abundant precipitation permits growth of enormous conifers such as
- Douglas- fir, Redcedular, Sitka, Spruce and redwoods.
(Much of the undergrowth is ferns and members of the blueberry family.)
In the interior of North America, much less precipitation and colder winter temperature support drought- resistant conifers such as Ponderosa and Lodgepole Pines and Englemann Spruce
Deciduous Forest
A moderate climate of hardwood deciduous trees which occur across much of North America, Europe and Asia. Much of this biome is has been exposed to human disruption for agriculture and urban development.
There are usually 15-25 species of trees including;
- Maples
- Oaks
- Poplars
- And Birches
Springtime Sun passes through the seasonally leafless to reach diverse undergrowth flora. Soils are rich in nutrients from yearly leaf fall, and moderate temperatures and precipitation promote decomposition, while the cool winters promote accumulation of organic materials.
Temperature Grassland
Before settlement, this biome was occupied by most of the western midlands united states, where it is dominated by the blue- stem and buffalo grasses.
Fire helps maintain grass populations in this biome.
- Lack of precipitation also prevents many species of trees from growing, and those trees that usually do grow are in low moisture areas
- Where there is enough moisture to support decomposition, the soils accumulate nutrients, providing some of the most productive agricultural lands.
Desert
Desert occurs in continental interior around the North and the south of the equator from 25-35 degrees.
Wind patterns prevent this biome from receiving more than a few centimetres of precipitation yearly.
The deep- rooted plants are adapted to store water, like a cactus.
Primary production is low and soils are poor in nutrients but may have high surface salt evaporation.
Chaparral
Like Deserts, the distribution of Chaparral reflects a narrow range of climate conditions and occurs on western edge of continents from 32-40 degrees north to south of the equator.
Precipitation ranges from 35-70cm per year, usually falling in 2-4 months.
Typically plants are;
- Yearly herbs
- Evergreen shrubs
- And small trees
Typical Woody Species;
- Olives
- Eucalyptus
- Acacia
- Oaks
(Always drought Resistant and often adapted often adapted to withstand fire. Limited precipitation means soils are not rich in organic materials)
Savannah
Tall, perennial, grasses dominate this biome which occurs in eastern Africa, southern South American and Australia.
Rain is seasonal and ranges from 75- 150 cm per year.
Scattered trees and shrubs usually drop their leaves in the dry season to protect moisture.
Animal diversity can be high and include the large mammals well known in Africa.
Rain Forest
This moist, highly diverse forest extends North and south of the equator from 10 degrees N to 10 degrees S. (Imagine line around earth)
Yearly rainfall is commonly more than 250cm, and tree diversity alone often exceeds 300 species per hectare.
- Trees grow tall, and many have buttressed roots for support.
- Lianas and other epiphytic plant are common.
- Most leaves are evergreen and leathery and many have long pointed tips that facilitate drainage of excess moisture.
Due to the high temperature and heavy rains, decomposition, is very rapid, preventing the accumulation of organic material in clay-rich or sandy soils
