Welcome to MAF Biosecurity New Zealand’s Didymo Science Seminar Welcome to MAF Biosecurity New...

Welcome to MAF Welcome to MAF Biosecurity New Zealand’s Biosecurity New Zealand’s

Didymo Science SeminarDidymo Science Seminar

24 July 2007, Wellington

Christina Vieglais, Christina Vieglais, Didymo Science Programme LeaderDidymo Science Programme Leader

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IntroductionsIntroductions

• MAFBNZ Didymo Response Team (Chris Bicknell, Frances Velvin, Jan Amann, Lesley Wilson, Judith Hamblyn, Jeff Donaldson, Fleur Petricevich, Matt Thorpe)

• Our Sponsor– Andrew Harrison, Chief Technical Officer and Acting Director of

Post Border

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MAF BNZ Post Border GroupMAF BNZ Post Border Group• Committed to developing a programme with

partners to manage didymo into the future

• Knowledge gained during the incursion response can enable partners to make well-informed decisions

• Sharing of knowledge, skills and resources is vital to effective long term management

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Sharing for ScienceSharing for Science

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Didymo Incursion ResponseDidymo Incursion ResponseScience ProgrammeScience Programme

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New

Arr

ival

s

Investigate

Initial Response Eradicate

ControlManage

Ass

essm

ent

Cri

teri

a

Ass

essm

ent

Cri

teri

a

Detect

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Incursion Response PolicyIncursion Response Policy

Key criteria to determine an appropriate response• The technical feasibility of achieving the response

objectives using the measures proposed; and

• The costs and benefits associated with the response objectives and measures proposed (including social, environmental, cultural costs and benefits)

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Assessment Criteria Assessment Criteria

• Technical feasibility ←science• Practical• Benefit – cost• Strategic• Acceptable• Priority• Resource availability

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Required Burden of ProofRequired Burden of Proof100

80

60

40

20

>95% = significant

<95% = not significant

>90% = beyond reasonable doubt

>75% = compelling evidence

>51% = preponderance of evidence

<51% = not guilty

Source: Haas, Glen, E., Journal of Forestry Sept 2003

Science Judiciary

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Didymo Response ChallengesDidymo Response Challenges• Absence of basic information• Potential for economic, environmental, cultural

and social impacts• No known methods for control or eradication • Can’t control natural pathways of spread• Requires change in human behavior to reduce

spread

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SCIENCESCIENCE

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Didymo Science Programme ObjectivesDidymo Science Programme Objectives

To provide validated information onidentification, detection, distribution,

impacts, containment, control

To Inform decision-making on response options

What are the impacts and risks? Can we contain, control or eradicate???

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Need validated informationNeed validated informationQuestions Studies

• What harm will it cause?

• Where else is it?• How will we know if it has spread?

• Can we keep it from spreading?• Can we reduce the pop / impacts?

DISTRIBUTIONDISTRIBUTION

IMPACTSIMPACTS

CONTROLCONTROL

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Didymo Science / Technical StudiesDidymo Science / Technical Studies

– Ecology I and II– Trout Impacts

– Likely Environments Map– Sampling Methods– Delimiting Surveys– Molecular Detection

– Decontamination– Survival – Control Methods– Spring-fed Creeks

DISTRIBUTIONDISTRIBUTION

IMPACTSIMPACTS

CONTROLCONTROL

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Initial anecdotal observations included:

-Environmental (other algae, insects, fish)

-Health (itchy eyes & skin)

-Water Quality (taste and odour)

-Recreational (fishing, boating etc)

-Aesthetic (unattractive)

-Economic (clogging water intakes, fishing)

Potential Impacts in Nov 2004Potential Impacts in Nov 2004

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Didymo Organism Impact AssessmentDidymo Organism Impact Assessment

What are the impacts to values not easily measured?• Delphic Study – perceived impacts

Current Assessment: High to extreme impacts on all core values (environmental, economic, social and cultural)

Can we measure any quantitative impacts?• Science Studies: Ecology and Trout Studies

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Didymo Economic Impact AssessmentDidymo Economic Impact Assessment

Assessment of potential economic impacts if didymo spreads

• provides a baseline relative to which to assess incursion response options

• avoidance of or reduction in impacts comprises the benefits of intervention, for comparison with control costs

Potential present value impact over eight years est. $57 to 285 million

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Impact Study OutputsImpact Study Outputs

• Ecology I - algae, benthic inverts (completed Dec 2005)• Ecology II – plus drift inverts, native fish, pH, DO (today)• Trout Impacts - (today)

• Eco study results used in conjunction with LEM may reduce uncertainty about potential ecological impacts to specific sites

Transfer to Partners

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High

Low

Habitat Suitability

Potential distributionPotential distribution- South Island- South Island

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High

Low

Suitable habitats in NZ

Potential distributionPotential distribution- North Island- North Island

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# o

f d

idym

o c

ells

at

a s

ite

Time

Drift netDNA

method

Drift netmicro

method

Visualmicro

method

Relative Limits of Detection of Visual, Microscopicand DNA Analysis Methods for D. geminata

Assumptions: Growth of didymo in a river is exponential when flows are stable andbelow scouring velocity

Benthicmicro

method FLOODS

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Gomphoneis(60-100 m)

Gomphoneis Navicula(20-70 m)

Gomphonema(up to ~100 m)

Frustulia(50-60 m)

Achnanthidium(5-25 m)

Epithemia(20-60 m)

Tabellaria(30-50m)

Encyonema(20-40 m)

Cymbella(25-35 m)

Diatoma(15-40 m)

Synedra(up to ~200 m)

Didymosphenia (80 – 130m)

50 m

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Distribution Study OutputsDistribution Study Outputs

• Delimiting Surveys (ongoing since Dec 04)• Likely Environments Map I (completed Mar 05)• Sampling Methods Study (completed Sep 06)• DNA Detection Study (today)

• Sampling and Analysis Protocols (in use)• Updated LEM (today)

Transfer to Partners

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Didymo ControlDidymo Control

– Preliminary lit review : No proven control methods– Decontamination methods showed promise– RFP notified to trial control methods– Efficacy, impacts, feasibility, duration, and costs– Nine proposals received; NIWA commissioned– Chemical control most likely solution, if any

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Control Study OutputsControl Study Outputs

• Decontamination Study (completed Feb 05)• Survival Study (completed Dec 06)• Control Trials (today)• Spring-fed Creek Study (today)

• Cleaning Methods (completed)• Potential Control Tools (dependent on results)

Transfer to Partners

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Purpose of SeminarPurpose of Seminar• facilitate technical knowledge transfer

• assist partners in making technical decisions

• bring closure to the 2006/07 scientific research programme

• update partners on the 2007/08 operational programme.

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Collective EffortCollective Effort• Biosecurity New Zealand Didymo Incursion Response

Team

• Didymo Technical Advisory Group – expert objective advice

• Didymo Science Providers – desktop, laboratory and field studies

• Didymo LTM Partners – skills, experience, wisdom

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Didymo Response and LTM ObjectivesDidymo Response and LTM Objectives

• slow the spread of didymo and other freshwater pests throughout New Zealand

• protect valued sites and at risk species• mitigate the impacts of didymo on affected

sectors• maintain the North Island free of didymo for as

long as possible