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The Management of Invasive Species The Management of Invasive Species in Marine & Coastal Environmentsin Marine & Coastal Environments

Module 5Module 5

Incursion ManagementIncursion Management

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Module 5 ObjectivesModule 5 Objectives• Describe the strategies available for Describe the strategies available for

managing marine and coastal managing marine and coastal invasive species, once they have invasive species, once they have become establishedbecome established

• Highlight the differences between the Highlight the differences between the various incursion management various incursion management strategiesstrategies

• Introduce the techniques used in Introduce the techniques used in incursion management incursion management

• Describe the decision-making process Describe the decision-making process for selecting the appropriate strategyfor selecting the appropriate strategy

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StrategiesStrategies

• EradicationEradication• ControlControl• Impact mitigationImpact mitigation• Do nothing Do nothing

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This is a worst-case scenario, although there are many examples. Doing nothing is the only option when an invasion is so out of control that any attempts to do anything would be prohibitively expensive and futile. The expenditure is not considered worthwhile, and money and resources would be better allocated to dealing with more tractable IAS.

Do nothing4

To reduce the severity of impacts an invasive species iscausing, rather than managing the population itself.Impact

mitigation3

Although individuals will still be present, they will be atlower densities and/or in fewer, contained areas thanbefore control was initiated.Control2

To ensure that no individuals of the targeted IASpopulation exist at the end of the programme. Eradication1

GoalsManageme

nt option

Order ofpreferenc

e

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ContainmentContainment

Don’t wait until it is too late – immediate action can save large amounts of time

and money.

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Darwin Marina / Black striped mussel

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Developing the StrategyDeveloping the Strategy

• Mechanical/physicalMechanical/physical e.g. removals by hand (divers), e.g. removals by hand (divers), mechanical harvesting or the creation of physical barriersmechanical harvesting or the creation of physical barriers

• ChemicalChemical - e.g. chemical dosing, toxic baits, application of - e.g. chemical dosing, toxic baits, application of an inorganic or organic herbicide, larvicide or other an inorganic or organic herbicide, larvicide or other pesticidepesticide

• BiologicalBiological – e.g. a target-specific pathogen, parasite, – e.g. a target-specific pathogen, parasite, predator, biopesticide, genetic manipulation, reproduction predator, biopesticide, genetic manipulation, reproduction manipulation or habitat modification (e.g. salinity change by manipulation or habitat modification (e.g. salinity change by salt dosing or freshwater inundation).salt dosing or freshwater inundation).

Use all sources of information about the IAS (national, regional

and international) to help decide how best to manage it

Three categories:

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Approaches to ControlApproaches to Control

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Mechanical ControlMechanical Control • Labour-intensive and often expensive -Labour-intensive and often expensive -

especially where there are dense especially where there are dense infestations or when an IAS is wide-spread infestations or when an IAS is wide-spread and occurs in remote or inaccessible areas. and occurs in remote or inaccessible areas.

• Advantage of being target specific and that Advantage of being target specific and that non-target and environmental impacts are non-target and environmental impacts are usually minor. usually minor.

• Often the best choice when infestations are Often the best choice when infestations are small and easily accessible, because small and easily accessible, because individual IAS may be specifically targeted. individual IAS may be specifically targeted.

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Chemical ControlChemical Control

• Application of chemicals (agents) directly Application of chemicals (agents) directly to water column, sediments or target to water column, sediments or target speciesspecies

• Killing or Sterilising target speciesKilling or Sterilising target species• Range of options available for various Range of options available for various

applicationsapplications• Legal and safety/health constraints Legal and safety/health constraints • Limited applicabilityLimited applicability

Involves:

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Biological ControlBiological Control

• Control/eradication of target species by Control/eradication of target species by another organismanother organism– insect, bacteria, virus insect, bacteria, virus – biological product (hormone)biological product (hormone) – genetic or sterility manipulationsgenetic or sterility manipulations

• Host-specific pathogen, parasite or Host-specific pathogen, parasite or predatorpredator

• Negligible side effects on native speciesNegligible side effects on native species

Involves:

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Biological ControlBiological Control • The time and expense required to identify, screen and test candidate control The time and expense required to identify, screen and test candidate control

agents;agents;• The time required for the released agent to multiply and cause the required The time required for the released agent to multiply and cause the required

effect effect • Uncertainty about the level of control the agent will ultimately bring to bear Uncertainty about the level of control the agent will ultimately bring to bear

on the targeted population;on the targeted population;• The potential for the agent to exert an unexpected effect on native species or The potential for the agent to exert an unexpected effect on native species or

communities;communities;• The population regulation mechanism underlying the principle of biological The population regulation mechanism underlying the principle of biological

control, which does not anticipate eradication but reduces the invading control, which does not anticipate eradication but reduces the invading population density and fitness, with the prey/host or predator/parasite population density and fitness, with the prey/host or predator/parasite relationship achieving a dynamic balance. relationship achieving a dynamic balance.

Disadvantages:

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Biological ControlBiological Control 1. Self sustaining methods:

- Classical biological control: the introduction of a natural enemy from the original range of the IAS

- Habitat management: enhancing the populations of native predators and parasitoids

- Adding to the IAS’ enemies (reared or cultured and released in large numbers) when an outbreak of the IAS has happened

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Biological ControlBiological Control 2. Non-self sustaining methods:

- Inducing host resistance against the IAS- Biological chemicals. These are chemicals

that are naturally produced by living species, and effective against certain introduced species

- The use of pathogens, parasites or predators that will not be able to reproduce or survive in the environment

- Mass release of sterile males

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Caution:

• It is critical that national legislation provides for tight controls and legal requirements, including risk analysis as an integral part of decision making on whether introduction of a classical biological control agent should be authorised.

Such risk analysis should include all risks, including those for native biological diversity (including endemic species) in the area where the agent would be released.

A control agent approved for one country should hence not automatically be approved for another country.

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Assessing the Feasibility of Assessing the Feasibility of Available OptionsAvailable Options

Need to analyse the following: • Background informationBackground information relating to the species in question. relating to the species in question.

This should include biological, ecological and biogeographic This should include biological, ecological and biogeographic information, as well as the previous invasion history of the information, as well as the previous invasion history of the species.species.

• Extent of the invasionExtent of the invasion, including size/density of the population, , including size/density of the population, and geographic area covered.and geographic area covered.

• Available methods for the Available methods for the management optionmanagement option being being evaluated.evaluated.

• Case studiesCase studies of other attempts at managing invasions with of other attempts at managing invasions with similar characteristics or conditions.similar characteristics or conditions.

• Resources Resources available, including man power, equipment and available, including man power, equipment and budgetbudget

• Cost-benefit and risk analysis.Cost-benefit and risk analysis.

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EradicationEradication

• To restore the managed area to the condition it To restore the managed area to the condition it was in before the introduction of the alien species.was in before the introduction of the alien species.

• To accomplish the above by removing all evidence To accomplish the above by removing all evidence of the introduced species.of the introduced species.

• To maintain the managed area free of the To maintain the managed area free of the introduced species following the eradication introduced species following the eradication programme.programme.

Objectives :

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ControlControl Control involves reducing the

numbers of an IAS to below pre-set levels, or containing its population

within a defined area.

• Preferable when eradication is not appropriate Preferable when eradication is not appropriate or feasibleor feasible

• Can be used for short-term relief from impacts, Can be used for short-term relief from impacts, or for ‘holding pattern while other options are or for ‘holding pattern while other options are investigatedinvestigated

• Typically more practical, less damaging optionsTypically more practical, less damaging options• More affordable in the short-termMore affordable in the short-term

– But require long-term fundingBut require long-term funding

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Mitigation and MonitoringMitigation and Monitoring

Last Resort Strategies

• Impact MitigationImpact Mitigation

• Monitoring / measuring Monitoring / measuring changechange

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Key PointsKey Points • The ultimate goal of IAS management is to The ultimate goal of IAS management is to minimise threatsminimise threats

to biodiversity, human health & welfare and economiesto biodiversity, human health & welfare and economies• Once a species has become established, there are four Once a species has become established, there are four

options: options: eradicate, control, mitigate or do nothingeradicate, control, mitigate or do nothing• Waiting Waiting for all possible information before deciding on how for all possible information before deciding on how

to deal with a newly-reported IAS can be disastrous. to deal with a newly-reported IAS can be disastrous. • Use all Use all sources of informationsources of information about the IAS (local, national about the IAS (local, national

and international) to help decide how best to manage itand international) to help decide how best to manage it• An An open and transparent processopen and transparent process is more likely to win is more likely to win

public and governmental supportpublic and governmental support• One agencyOne agency or organisation should be or organisation should be responsibleresponsible for the for the

entire process, with complete authority to make decisions entire process, with complete authority to make decisions and execute themand execute them

• Correctly identifyingCorrectly identifying the alien species is the first step in the alien species is the first step in deciding how to manage itdeciding how to manage it

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Local fishermen have reported that a different fish species Local fishermen have reported that a different fish species hashas

been turning up in their catch during the current fishing been turning up in their catch during the current fishing season.season.

This species appears to be well-established and occurring inThis species appears to be well-established and occurring inlarge densities; and its presence has resulted in a decrease inlarge densities; and its presence has resulted in a decrease intheir normal catch. their normal catch. 1.1. How would you find out whether it is an invasive species How would you find out whether it is an invasive species

or an invasive alien species, while finding this out what or an invasive alien species, while finding this out what steps can you take?steps can you take?

2.2. Would you get the general public to assist? How? Would you get the general public to assist? How? 3.3. How would you choose/ evaluate a method of control? How would you choose/ evaluate a method of control? 4.4. If you were to choose biological control, what factors If you were to choose biological control, what factors

should you consider?should you consider?5.5. If you were to choose chemical control, what factors If you were to choose chemical control, what factors

should you consider?should you consider?6.6. What if all attempts to eradicate the species have failed, What if all attempts to eradicate the species have failed,

what can you do?what can you do?