Global Ecosystems
Natural vegetation
the plant cover that would establish itself in an area without human interference
Many areas of the earth have been modified by humans
Climate changes with latitude and longitude are reflected in changes in vegetation. These changes are gradual not abrupt.

Plant Features
life form of a plant refers to its physical structure, size and shape. E.g. trees, shrubs, lianas and herbs.
Habitat = conditions of slope, water drainage, and soil type that influence the vegetation cover.

Biomes
the largest recognizable subdivision of terrestrial ecosystems.
include the forest, savanna, grassland, desert and tundra biomes.

The Forest Biome
six major types of forest:
low latitude rainforest
monsoon forest
subtropical evergreen forest
midlatitude deciduous forest
needleleaf forest
schlerophyll forest

The Low Latitude Rainforest
found in the equatorial and tropical zone
continuously warm temperatures with consistent abundant rainfall.
a forest of tall, closely set trees with multilayered canopy
the largest diversity of species of any lifezone.

The Monsoon Forest
found in a wet-dry tropical climate
dry season results in a deciduous forest that sheds its leaves
an open canopy allowing more development in the lower forest layers.

The Subtropical Evergreen Forest
is associated with the moist subtropical climate
vegetation consists of broadleaf and needleleaf evergreen trees
little natural forest remains due to agricultural development.

The Midlatitude Deciduous Forest
tall dense canopy in summer
sheds its leaves in winter in response to the cold temperatures.

The Needleleaf Forest
a few species of tall cone-shaped mostly evergreen coniferous trees.
these trees create a continuous deep shade at ground level which inhibits the growth of shrubs and herbs.
is associated with the boreal forest climate and the high elevations of mountainous areas.

The Schlerophyll Forest
develops in the Mediterranean climate.
trees have adapted to the dry, hot summers by producing small, hard, thick leaves that minimize water loss.
Trees have hard leathery leaves

The Savanna Biome
a product of the tropical wet-dry climate
Changes from woodland to thorn-tree grassland with increasing dryness.
adaptation to dryness includes deciduous habit and small leaves or thorns.
Trees are widely spaced and area is prone to fires in dry season

The Grassland Biome
found in the midlatitude and subtropical zones which have well developed winter and summer seasons.
includes both tall-grass prairie and steppe.
Steppe vegetation grows in the semi-arid subtype of the dry continental climate.

The Desert Biome
includes both desert and semi-desert subtypes.
semi-desert ranges from the tropical to midlatitude zone
vegetation includes sparse xerophytic shrubs adapted to a long hot dry season with a short wet season.
Desert vegetation includes spiny shrubs, succulent plants and hard grasses.Many areas with no vegetation.

The Tundra Biome
found at high latitudes and high elevations
include low herbs, dwarf shrubs, sedges, grasses, mosses and lichens
high latitudes plant growth influenced by long winters with little light and short cool summers with very long days.
Permafrost restricts drainage and root development.

The Tundra Biome - Elevation
As elevation increases, temperatures decrease and precipitation increases
this leads to a sequence of vegetation zones or life zones related to altitude.