Preventing invasive species from getting to a site, establishing and increasing their population is the most effective measure. Prevention is also sometimes referred to as quarantine and involves identifying the pathways which an invasive species may use to get to a site, assessing the risk of this and applying procedures to minimise each risk. The identification of pathways should be done often, particularly before any travel (including that of the project team) to a site.

All existing and potential invasive species should be considered, i.e. invasive species to be targeted as part of the project, plus any that are not currently at the site but could pose a threat if they got there. Effective prevention means putting as many blocks as possible along different parts of the pathway to make it very difficult for the invasive species to move along that pathway.
3 lines of biodiversity defence
Seeds and other plant parts (and other hitchhikers in the soil) can be transported from site to site by machinery.
(Photo: John Mather)


Surveillance is monitoring to detect whether an incursion has occurred. An incursion is when an invasive species has evaded the prevention measures and arrived at the site. This is a long-term activity, with on-going or regular surveillance in place at the site. It is different from outcome monitoring which is done to see the effects of the invasive species management activities.

Incursion Response

A project management decision-making plan will be in place that assists with the planning of how to confirm that an incursion has occurred, what further information is required and what is the best way to handle the incursion.

If the surveillance suggests that an incursion has occurred, the project team needs to respond to the threat. A range of information will be required to decide how to react, for example:
  • What is the invasive species?
  • What size is the incursion? (e.g. wind-blown seeds, a single plant/animal, small group of plants/animals, large number of plants/animals)
  • What is the breeding status of the plants/animals? (e.g. seedlings, mature (fruiting) plants, pregnant female rodent, ant colony with queen(s), etc.)
  • How long has the species been on the island? (i.e. recent incursion or old incursion that has gone undetected) 

Community involvement in Biosecurity

As most pathways involve people travelling to and from the site, much of the prevention work will be undertaken not by the project team, but by the wider public and especially local communities and visitors. Get the input of local communities and other site users to help work out biosecurity measures that will be effective in the local situation.

Identify what people value on invasive-free sites (e.g. larger harvest from plants of cultural importance as invasive plants are not competing) so they have an interest in keeping the site invasive-free.

Visitors need to be taught which invasive species threaten the site and what they need to do to prevent re-invasion. This will require the project team to conduct a public awareness exercise and consult widely with stakeholders to inform the public of the role they can play and to motivate them to take biosecurity seriously.