Lecture 22: Vector Control as a Management Option Flashcards
Prevention?
stop a species from being introduced or established
L> need the most cost effective and practical way to deal with invasions
Common trend in impact-density relationship for introduced sp?
- S relationship
Indicate where the following priorities go in invasion progression:
- Prevention
- Eradication
- Control
- Effective control is no longer possible
- prevention should be before establishment occurs
- eradication is once establishment has occurred
- control is for when it is impossible to eradicate them bc they’ve generated a large enough population and have spread
What is essential for prevention?
- early detection
- depends on the effectiveness of monitoring and taxonomical identification
Problem: most invasions are not recognized right away and are not monitored
What are methods of prevention?
- Vector Control
- Quarantine
- Habitat management (to reduce vulnerability)
Vector control?
- control movement of organisms (travel and delivery)
ex: Shipping: ballast water treatments
ex: recreational boats: cleaning them
ex: Canals: electric barriers
Vector Control:
- Ballast water treatment
- mid oceanic exchange
- filtration
- chemical sterilization
- uv light
- heat treatment-good for cold dep organisms
- de oxygenation - use bubbled nitrogen
Counter productive public information. Explain this with the example of zebra mussels.
MYTHS
1. Noah fallacy
- it only takes one
L> “How can I possible be sure I got every last one off my gear”
L> truth: most larvae die, mussels might not reproduce successfully, you NEED HEEPS OF LARVAE. SO REMOVE THEM. Propagule pressure matters
- It only takes one mistake
- “So why bother trying to prevent it”
L> reality: invasion success increases with propagule pressure - Invasions are inevitable
- “ SO WHY BOTHER”
L> Reality: a particular invasion is not necessarily inevitable. But even if the invasion is only delayed, we can buy ourselves time to research methods of control and eradication
Quarantine?
- form of vector control
- prohibits organisms from entering a new range
- most invasions begin with the arrival of a few individuals. The cost of excluding this is trivial compared to the cost of controlling the established form (rapid growing)
- the ability off a nation to restrict the movement of invaders across borders is governed by international treaties.
Ex of quarantine?
- Asian longhorn beetle
L> via crate from china
L> US banned imports of untreated raw lumber and wood packing from ASIA
*Can did too later but it was too late for Canada though bc the beetle was found here
1912 Quarantine Act in USA
- occurred after the chinese chestnut blight fungus happened
- bans the unauthorized import of plant material to limit introduction of weeds and insects
- Habitat management
L> agriculture?
- modifications to reduce vulnerability to invasion
ex: agricultural fields: made diverse using polycultures instead of monocultures
L> pest insects are lower in polycultures
- Habitat management
L> Forests?
- diverse habitats compared to agricultural systems. But forestry practices simplify forests for efficiency in timber production
- in theory, mixed species and mixed age stands would be least subject to damage by insect pests
- Habitat management
L> Reducing fire freq
- fire favours invasive grasses by removing native competitors and freeing up resources
- many invasive grasses produce dormant seeds that germinate prolifically after a fire.
- Habitat management
L> Design of nature parks?
- Goal = reduce propagule pressure :
1. limit tourist activity
2. reduce proximity to cities
3. reduce road access / traffic
4. keep boundary line simple as possible bc the more circumference = more changes for something to invade
**reduce ratio of perimeter to interior
