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Grassland
草地
What is a Grassland?
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
Deep-rooted grasses and oats are commonly seen in grasslands
very few trees and shrubs in a grassland
Types of grasslands
1. Tropical grassland
A continuous cover of perennial grasses are found
Location close to the equator, often bordering a rainforest. Africa, South America, etc.
Climate Hot, dry and wet seasons
Types of grasslands
2. Temperate grasslands
Prairie is an example of Temperate Grassland
Location Farther from the equator e.g. the interior of North America.
Climate Hot summers and cold winters.
Rainfall Little rain fall
Grasslands in Hong Kong
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
High annual rainfall would forms a forest or woodland.
Temperature
around 12-30 C
Rainfall around 2214.24 mm per year
Reasons for the lack of grassland
3. Latitude Not enough land Not near the equator At subtropical latitudes Not lying on the region of grasslands
Ways to form grasslands
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 Grass absorb the toxic gases in the a
tmosphere. The secretion of grass can kill the ba
cteria ,reduce the concentration of bacteria in the atmosphere.
Absorb and adsorb the dust.
Use of Grassland
城市之肺 ,房屋之窗 Grass carry out photosynthesis Absorb CO2, release O2 1.5g per meter square in 1hour
Use of Grassland
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
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