Invasive Species

5 stages of invasion and be able to distinguish between a non-native/exotic and invasive species using them

1. transport

2. introduction

3. establishment

4. spread

5. impact

non-native would stop at spread and stay local, while invasives would spread and have negative impacts

main reasons why non-native species are an issue

can’t predict if a non-native species will become invasive

hard to eradicate

displace natives

cause agricultural damage

factors that can help determine whether an introduced species will become invasive

• propagule pressure

• characteristics of successful invaders

  • R-selected species

  • high dispersal rate = high propagule pressure

  • use a resource in a new way

• characteristics of communities that make them easier to invade

  • climate and environment are similar to native range

  • species-poor communities

  • disturbed communities

examples of the effects of introduced species at different levels of biological organization

1. genetic - hybridization

2. individual - toads now eat fire ants

3. population - fence lizards shake off fire ants

4. community - seed dispersal altered bc fire ants eat seeds and native ants disperse them

5. ecosystem - altered canopy alters function

Explain why controlling invasive species can be complex

4 stages of invasive species management as they relate to the timing of the invasion and cost of management

1. prevention (least expensive)

2. eradication

3. containment

4. mitigation (most expensive)