Download Grassland

Grassland
草地
What is a Grassland?
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A open, continuous and fairly flat areas of
grass and other herbs
cover 40 percent of the earth's surface
Location
Between temperate forests
and deserts.
Temperature Between -20°C to 30°C
Rainfall
About 500 to 900 mm of rain
per year
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Deep-rooted
grasses and oats
are commonly
seen in grasslands
very few trees and
shrubs in a
grassland
Types of grasslands
1. Tropical grassland
Location
Climate
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close to the equator, often
bordering a rainforest.
 Africa, South America, etc.
Hot, dry and wet seasons

A continuous cover of perennial grasses
are found
Types of grasslands
2. Temperate grasslands
Location

Climate
Hot summers and cold winters.
Rainfall
Little rain fall

Farther from the equator
 e.g. the interior of North
America.
Prairie is an example of Temperate Grassland
Grasslands in Hong
Kong
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On hillside
grass and shrubs under
0.3 meters in height
Small amount
Mainly found in the
New Territories
Varied ( mixture of
herbs and small shrubs)
Reasons for the lack of
grassland
1. Soil
Grasslands in.....
 Higher slopes are subjected to wind
exposure, poor soil condition and rapid
runoff.
 Lower slopes with poor soil conditions are
mainly formed after abandon of farmland
Soil erosion
Reasons for the lack of
grassland
2. Climate & Temperature
 Moderate climate
Temperature around 12-30 C
Rainfall
around 2214.24 mm per
year

High annual rainfall would forms a forest
or woodland.
Reasons for the lack of
grassland
3. Latitude
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Not enough land
Not near the equator
At subtropical latitudes
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Not lying on the region of grasslands
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Ways to form grasslands
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Fire is the factor to balance from forest
to grasslands.
Fires set by lightning and by humans
Perennial grasses and herbs are not
harmed by fires that destroy most
shrubs and trees.
Use of Grassland
大氣過濾器
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Grass absorb the toxic gases in the
atmosphere.
The secretion of grass can kill the
bacteria ,reduce the concentration of
bacteria in the atmosphere.
Absorb and adsorb the dust.
Use of Grassland
城市之肺 ,房屋之窗
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Grass carry out photosynthesis
Absorb CO2, release O2
1.5g per meter square in 1hour
Use of Grassland
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Grasslands are highly productive when
converted into agricultural uses
Since the soil is full of nutrients. The
organic material (i.e. decomposers)
makes the soil so productive
Conclusion
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Grassland in HK is a poor habitat for
vertebrates and most invertebrates
Since it provide neither food nor
protection
So, we need to conserve certain species
of grass or herbs
The End