Module 4

Fighting back!

Learning Outcomes

• At the end of this module you should be able to:

– identify and understand IAS management goals

– state some examples of successful eradications

– understand that IAS can be successfully eradicated or controlled

Fighting Back!

• The worldwide problem of IAS is serious

BUT

the outlook is not all doom and gloom!

• Around the world people are fighting back against unwanted invaders

What are the goals of IAS management?

• There are four options:

– Prevention

– Early detection & rapid response

– Eradication

– Control / Mitigation

Red Imported Fire Ant

Why manage IAS?

• Must have specific goals, such as:

– protecting an endangered species

– conserving biodiversity

– protecting human health

Eradication

• Campbell Island

– an 11,000 hectare sub-Antarctic island infested with 200,000 rats

– eradication necessary to protect rare native wildlife

– completed using 120 tonnes of rat bait dropped by helicopter

– the largest island eradication of rodents

Campbell Island teal Ship loading rat bait

Eradication

Increasing size of New Zealand islands from which rats have been eradicated

• Eradication of IAS on large islands is now possible due to:

– better techniques

– improved technology

– years of experience

Control

• Lake Wilson, Hawaii

– invaded by the aquatic weed Salvinia molesta

– multi-agency task force set up to address the problem

– used herbicide and mechanical removal to clear 38,000 m³ of weed from lake

– requires monthly maintenance to prevent regrowth

Before After

Mitigation

• Possum browsing

– threatens rare native New Zealand mistletoe plants

– individual trees are ‘tinned’ to prevent possums from climbing them

metal barrier on trunk

The way forward

• Eradication is now an achievable goal in many situations

• Often more than one species can be eradicated at a time

• Getting institutional buy-in is important

Summary

• Apathy is not an option!

• Techniques & resources for eradication are constantly improving

• There are numerous success stories from around the world

• Eradication is hard work but the results are worth it!