Transcript Invasive Species Powerpoint

Invasive Species
What is an Invasive Species?
• A species that has been introduced or is not native to an
environment
• Invasive species are generally harmful to the local habitat
or native species
• Unwanted pest
• Not all non-native organisms are invasive
More Examples of Invasive Species
• Grey squirrel
• American beaver
• Cane toad
Different Routes of Invasion
Most invasions are due to human activities:
• Plant or pet trade
• Commercial shipping
• Tourism
…and many other routes…
Quiz: What Characteristics Make A Good
Invader?
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Rapid reproduction
Fast growth
High dispersal
Tolerant to many different conditions
Able to live off many different foods
Used by humans
The Impact of Invasive Species
• Ecological:
– Reduce native biodiversity
– Direct predation on local species
– Spread of disease
– Upset balance of local ecosystem
The Impact of Invasive Species
• Economical:
- Very expensive - agricultural pests cause
millions of dollars of damage every year!
- Very expensive to eradicate invasive
species
Controlling Invasive Species
• Controlling invasive species once they have
become established is difficult.
• Control is also usually very expensive!
• There are four main ways that invasive species
are controlled:
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Physical control
Chemical control
Biological control
Prevention
Physical Control of Invasive Species
Controlling plants:
• Mechanical – excavation, strimming, etc.
• Removal of plants by hand
• Installation of growth barriers
Controlling animals:
• Culling
• Trapping and hunting
• Putting up barriers or fences
Chemical Control of Invasive Species
• Chemical control involves applying poison to
eliminate invasive species
• E.g. Eradication of rats on Henderson Island
– Use rodenticide (rat poison)
• Insecticides & pesticides
to control insect pests
• Herbicides (weed-killer)
to control plants
Biological Control of Invasive Species
• Uses a living organism to control invasive species
• This organism may eat the invasive species or
cause it to become diseased
• Biological control agents must be carefully
assessed before release to ensure the control
species will not become invasive itself
Seven-spot ladybird
Harlequin ladybird
Preventing Invasive Species
• Prevention is better than cure!
• Preventing invasive species
from being introduced
somewhere in the first place,
or preventing them from
spreading if they do arrive,
is the key to avoiding
long-term harm to ecosystems
Barrow Island Case Study
• Barrow Island is a small
island off the NW coast
of Australia that is home
to many species that
have become rare or
extinct on the Australian mainland
• This is partly due to a rigorous Quarantine
Management System (QMS) operated by Chevron,
which prevents invasive species from becoming
established on the island