IPM Flashcards
Invasive Species Defn
- non native to the ecosystem
- intro causes (or is likely to cause) economic or environmental harm or harm to human health
*1 of top 5 threats to biodiversity
*primarily human caused
Ecological impacts of Invasives
increased water use reduces availability to desired plants
adverse effects on soil chemistry
reduced biodiversity
Economic impacts of Invasives
reduced carrying capacity (livestock)
toxic to animals
costly to manage/remove
3 phases of invasion process:
- arrival and establishment (introduced and survives)
- spread (population growth)
- Equilibrium and Effects (becomes part of ecosystem with impacts to community)
3 Levels of Control of Invasives
- Prevention (public education, mgmt)
- Eradication (early detection, eradication if possible)
- Control (decrease impact to manageable level)
MT Noxious Weeds list (inverted triangle)
High priority/prevention
Class 1A
1B
2A
2B (abundant in MT)
3
Low priority/control (abundant)
4 attributes of successful weed mgmt:
- get beyond symptoms to root cause (minimize repeat efforts)
- no one answer (bio, chem, fire, mechanical)
- clearly defined goals (driven by bio/eco/socio)
- multi level approach
Chemical Weed Mgmt includes:
pesticides (any chemical used to control living substance) including: insecticide, rodenticide, fungicide, herbicide
Principle Uses of Herbicide are…
- must contact plant when susceptible
- remain long enough to be absorbed
- reach living cellular site at a concentration significant enough to disrupt vital process/structures
Herbicide mode of actions are:
- growth regulating
- amino acid synthesis inhibiting
- photosynthesis inhibiting
Herbicide Pros are:
less expensive than resource heavy approach
terrain has less impact
selective control
good for releasing in situ desirable plants
low labor
Herbicide Cons are:
may kill non-target plants
may increase plant toxicity
social concerns
danger to applicator/environment
health hazards
Where does herbicide go?
microbial decomp
chemical decomp
leaching
absorbed by clay/organic matter
run off
plant uptake
volatilization (air)
Mechanical Weed Managment is…
physically removing unwanted species (cutting/pulling) by use of a tool to remove or destroy plant material
2 types:
Top Removal and Complete Removal
*often used with other treatments
Pros of mechanical mgmt…
can target specific species/plants
no chemical side effects
Cons of mechanical mgmt…
expensive
specialized equipment
may not kill the plant
high disturbance
Biological Weed Management has 2 approaches:
- Classical
- targeted grazing
*key principle of both is selective herbivory
Classical Bio Mgmt
using natural enemies of weeds including insects, pathogens (bacteria and fungi) to control infestation
can take ~11 years
goal is to REDUCE invasives
Biocontrol Agents must be:
- destructive to noxious plant
- specific to host, harmless to others
- able to survive and reproduce in new environment
How do biocontrol agents act:
eat/destroy plant directly
create favorable conditions for infection by pathogen
change competitive relationships in community (seed eaters –> reduce seed set –> reduce competitive abilities)
Steps to deploy biocontrol agent:
- know the weed (home and invasive)
- determine host specificity (MANY trials)
- quarantine testing (choice or no choice)
- field testing
- mass rearing/release
- monitor!
Why not have goal to eradicate all invasive species?
There are multiple resource objectives and eradication would be costly and time consuming and diver resources from other needed objectives. Could also unintentionally create a niche for the invasive to come back (expensive cycle). You might also destroy unintended plants.
