Write an essay in which you describe how invasive alien plants affect the quality of water
and discuss various ways of controlling invasive alien plants including their advantages
and/or disadvantages.
EFFECT OF ALIEN INVASIVE SPECIES ON WATER QUALITY
• They form a continuous mat on the surface of water.
• This blocks light from reaching the lower levels of the water.
• Photosynthesis at the lower level of water stops.
• The plants die and decompose.
• The population of decomposers increases,
• using up large amounts of oxygen.
• Aquatic animals/ fish/frogs die
• due to lack of oxygen.
• This decreases the quality of water.
MECHANICAL CONTROL
• Removal of invasive species by hand or with machines
• Effective in controlling small populations
Advantage: minimizes harm to non-invasive plants and animals
Disadvantage: Labour intensive and time consuming
CHEMICAL CONTROL
• Uses chemicals /chemical compounds to control spread of alien invasive species
• Effective in both large and small populations
Disadvantage: possible contamination of land and water resources
• and may result in the killing of desirable plants and animal species.
• Target species may develop resistance to the chemicals
BIOLOGICAL CONTROL
• Uses a specific species to control the spread of alien invasive species
• Both indigenous and non-indigenous species may be used
• Can be both environmentally safe
• and successful Use of non-indigenous species may decrease alien invasive species.
and discuss various ways of controlling invasive alien plants including their advantages
and/or disadvantages.
EFFECT OF ALIEN INVASIVE SPECIES ON WATER QUALITY
• They form a continuous mat on the surface of water.
• This blocks light from reaching the lower levels of the water.
• Photosynthesis at the lower level of water stops.
• The plants die and decompose.
• The population of decomposers increases,
• using up large amounts of oxygen.
• Aquatic animals/ fish/frogs die
• due to lack of oxygen.
• This decreases the quality of water.
MECHANICAL CONTROL
• Removal of invasive species by hand or with machines
• Effective in controlling small populations
Advantage: minimizes harm to non-invasive plants and animals
Disadvantage: Labour intensive and time consuming
CHEMICAL CONTROL
• Uses chemicals /chemical compounds to control spread of alien invasive species
• Effective in both large and small populations
Disadvantage: possible contamination of land and water resources
• and may result in the killing of desirable plants and animal species.
• Target species may develop resistance to the chemicals
BIOLOGICAL CONTROL
• Uses a specific species to control the spread of alien invasive species
• Both indigenous and non-indigenous species may be used
• Can be both environmentally safe
• and successful Use of non-indigenous species may decrease alien invasive species.
