LESSONS LEARNED FROM RISK ASSESSMENT FOR BIOLOGICAL CONTROL ORGANISMS

BARBARA BARRATT

AGRESEARCH INVERMAY

NEW ZEALAND

South Asia Biosafety Conference - CERA 18-20 September 2013 New Delhi, India

OUTLINEEnvironmental risk analysis

• The framework

BC and risk assessment

• Why assess risk?

• What are the risks?

• How risk can be assessed

Weighing risks against benefits

Dealing with uncertainty

What we can learn from risk assessment for BCAs

‘Risk assessment’ sits within a wider risk analysis framework:

CO

MM

UN

ICAT

ION

& C

ON

SULT

ATIO

N

ASS

ESS

RIS

KS

ESTABLISH THE CONTEXT

IDENTIFY RISKS

ANALYSE RISKS

EVALUATE and RANK RISKS

TREAT RISKS

MONITOR

AND

REVIEW

From: Australian and New Zealand Risk Management Standard AS/NZS 4360

Moeed A, Hickson R, Barratt BIP 2006. Principles of environmental risk assessment of invertebrates in biological control of arthropods. In: Bigler F, Babendreier D, Kuhlmann U ed. Environmental impact of arthropod biological control: methods and risk assessment. CABI Publishing, Delemont, Switzerland. Pp. 241-253.

What is valued in the environment and what would be considered as harm? = risk hypothesis

Comprehensive list of what could happen, when and how?

Transparency at all stages

Likelihood and magnitude, ID uncertainty

Where can risks be managed? Conduct more research, monitor impacts

WHY ASSESS RISK?

To protect the things we value from harm

To systematically identify, evaluate and prioritise risks

To predict and avoid adverse impacts

Regulatory requirement

• Regulators need the results of a risk assessment for decision support

EXAMPLE: HSNO MINIMUM STANDARDS

NZ EPA must decline an application if the new organism [incl. GMO] is likely to:

“(a) Cause any significant displacement of any native species within its natural habitat; or

(b) Cause any significant deterioration of natural habitats; or

(d) Cause any significant adverse effect to New Zealand’s inherent genetic diversity”

EXAMPLE: HSNO MINIMUM STANDARDS

NZ EPA must decline an application if the new organism [incl. GMO] is likely to:

“(a) Cause any significant displacement of any native species within its natural habitat; or

(b) Cause any significant deterioration of natural habitats; or

(d) Cause any significant adverse effect to New Zealand’s inherent genetic diversity”

NZ’s values and public policy goals

EXAMPLE: USEPA

USEPA considers risk to be the chance of harmful effects to ecological systems resulting from exposure to an environmental stressor

A stressor is any physical, chemical, or biological entity that can induce an adverse response

Stressors may adversely affect specific natural resources or entire ecosystems, including plants and animals, as well as the environment with which they interact

USA’s values and public policy goals

BIOLOGICAL CONTROL

Pests often arrive without natural enemies

Natural enemies introduced to control pests• BCAs can be parasitoids, predators,

pathogens

Target pests can be animals, plants or pathogens

Three main types of BC• Classical BC – released into the

environment

• Inundative BC –not expected to establish

• Conservation BC – enhancing existing natural enemies

WHAT ARE THE RISKS FOR BCAS?Non-target impacts• BCA attacks species other than the target• NT attack leads to population impacts• BCA attacks valued species (e.g. other BCAs, endangered spp. )

Host range expansion• BCA ‘acquires’ additional hosts over time• Host preferences shift

Competition/hybridization with other natural enemies• BCA competes with or displaces existing natural enemies

• BCA hybridizes with related species compromising genetic integrity

Indirect effects• Complex and unpredictable impacts at other trophic levels• Food web effects/ environmental effects

HOW IS RA CARRIED OUT FOR BCAS?

Case by case:

1. Pre-introduction

2. In quarantine

Determine:

• Natural host range

• Impacts in other areas of introduction

• Potential host range in receiving environment

• Biotypes – BCA, target

• Host specificity• Determine taxonomic

breadth of hosts• ID candidates with

unacceptable risk

1. PRE-INTRODUCTION RA

Determine:

• Natural host range

• Impacts in other areas of introduction

• Potential host range in receiving environment

• Biotypes – BCA, target

• Biosafety record in the field

• How accurate were predictions?

1. PRE-INTRODUCTION RA

Determine:

• Natural host range

• Impacts in other areas of introduction

• Potential host range in receiving environment

• Biotypes – BCA, target

• Literature and databases• Collections• Field surveys

1. PRE-INTRODUCTION RA

Determine:

• Natural host range

• Impacts in other areas of introduction

• Potential host range in receiving environment

• Biotypes of BCA

• BCA biotypes can have different host ranges

• Ensure that source of BCAs is equivalent to that used in tests and released

1. PRE-INTRODUCTION RA

2. QUARANTINE TESTING

Most informative –predict potential host range

Choices to be made:

• Test species selection

• Type and design of tests

• What to measure

Discuss choices with regulators/ stakeholders

TEST SPECIES SELECTION – WEED TARGETS

Well defined process, tested and proven

‘Centrifugal phylogenetic testing ‘(Wapshere, 1974)

Target weed

Closely related species

Distantly related species

Less closely

related spp.

Profile of host

range

Include cultivated and valued plants

Testing sequence

Later refined:

• Too many false positives in cage tests

• Host selection cues being by-passed

• ‘Safe’ BCAs being rejected

Reverse testing sequence (Wapshere, 1989)

• Expose test plants at the critical host selection phase

• Only if positive, further tests at the next phase

TEST SPECIES SELECTION – WEED TARGET

Do adults oviposit on the plant?

Yes No

Do larvae feed on the plant?

Yes No

Do larvae pupate and emerge

successfully?

Yes No

Carry out larger scale or field tests on only these spp.

No further testing

No further testing

No further testing?

Example: Cinnabar moth for ragwort

biocontrol

TEST SPECIES SELECTION –INSECT TARGET

More challenging:

• Far more potential species

• Less well known taxonomically

• Rearing test species more difficult

• Extra trophic level

• Consider behaviour of target and BCA

List species with• Phylogenetic and ecological affinities between the target

and NT species

Determine target/NT range overlap • ID taxa most immediately at risk

• May require field surveys

Formulate list of test species most 'at risk' • Carry out tests on these in quarantine

• Include beneficials, other BCAs, insects of commercial, cultural or iconic significance

Evaluate the results of initial tests• Determine the need for further testing

TEST SPECIES SELECTION –INSECT TARGET

Kuhlmann, U., Schaffner, U. and Mason, P.G., 2006. Selection of non-target species for host specificity testing. Pp. 15-37 In: Environmental impact of invertebrates for biological control of arthropods: methods and risk assessment F. Bigler, D. Babendreier and U. Kuhlmann (Ed.) CABI Publishing, Wallingford, Oxford

PRIORITY RANKING OF NON-TARGET

INVERTEBRATES (PRONTI)Developed for GM plants:• Uses database of invertebrates in receiving

environment• Data for each species on biology, ecology,

resilience, testability, social and economic value (published info)

• Model calculates combined score:

(hazard x exposure) x (status* + value + testability)resilience**

* status = combination of biomass, food web and special function scores

** resilience = attributes that might mitigate the risk (e.g. dispersal ability, a high intrinsic rate of population increase etc.)

PRIORITY RANKING OF NON-TARGET

INVERTEBRATES (PRONTI)Developed for GM plants:• Uses database of invertebrates in receiving

environment

• Data for each species on biology, ecology, resilience, testability, social and economic value (published info)

• Model calculates combined score:

(hazard x exposure) x (status* + value + testability)resilience**

* status = combination of biomass, food web and special function scores

** resilience = attributes of a species that might mitigate the risk (e.g. dispersal ability, a high intrinsic rate of population increase etc.)

PRONTI FOR BIOLOGICAL CONTROL

Being evaluated for BCAs for invertebrate targets

Advantages:• Transparent process for regulators• Peer-reviewed published information• More objective way of selecting NT species• More species considered

Disadvantages:• Database of invertebrates needed for the

receiving environment

No-choice tests• Conservative• Is NT in fundamental host range?• Prone to false positives

Choice tests• Which species is preferred?• Is a NT attacked when target present?• Not necessarily indicative of field situation

Sequential tests• Exposure to successive NTs with periodic re-exposure

to the target

QUARANTINE TESTING – TEST METHODS

BIREA - Biocontrol Information Resource for EPA Applicantshttp://b3.net.nz/birea/

QUARANTINE TESTING – TEST METHODS

Test design – pilot tests to determine:• BCA : host ratio• Exposure period• Arena size

Critical factors:• Vigour and performance of organisms• Appropriate controls and replication• Consistent environmental conditions

• food plants etc.

QUARANTINE TESTING - WHAT TO MEASURE

Non-target attack rates (target cf. NT)

• Compare developmental rates• Rear BCA to check viability/fitness of

offspring• Dissect survivors (insect target)

Impact on NT hosts

• Survival, feeding, fecundity (insect target)• Growth, damage, seed set etc. (weed

target)

QUARANTINE TESTING - INTERPRETATION

Risk of over- or under-estimation of host range

• Artificial conditions; abnormal behaviour

• Environmental cues absent

• Poor performance of BCA/ poor fitness of test species

Data analysis

• Interpretation of rare events

Withers TM, Carlson CA, Gresham BA 2013. Statistical tools to interpret risks that arise from rare events in host specificity testing. Biological Control 64: 177-185.

WEIGHING RISKS AGAINST BENEFITS

Risks identified and assessed pre-introduction and in quarantine tests

For each risk/benefit evaluate:

• How likely is this to happen?

• If it did, what would be the consequences?

Likelihood of an adverse effect

Magnitude of adverse effect

highly improbable minimal highly localised impact, affecting a few individuals of a

community, no ecosystem impact

improbable (remote) minorlocalised and contained reversible impact, some communities

temporarily damaged, no impact on species or ecosystems

very unlikely moderatemeasurable long term damage to communities, limited spread,

medium term individual ecosystem damage, no species damage

unlikely (occasional) majorlong term/irreversible damage to localised ecosystem but no

species loss

likely massiveirreversible ecosystem damage including species loss

very likely

extremely likely

FRAMEWORK FOR EVALUATING ADVERSE RISKS

Likelihood of a beneficial effect

Magnitude of benefit

highly improbable minimal highly localised benefit, affecting few individuals members

of communities of flora or fauna, no ecosystem benefit

improbable (remote) minor local and contained environmental benefit; no discernible

ecosystem benefit

very unlikely moderatemeasurable benefit to localised plant/animal communities

unlikely (occasional) major long-term benefit to localised ecosystems

likely massivelong-term, widespread benefits to species and/or

ecosystems

very likely

extremely likely

FRAMEWORK FOR EVALUATING BENEFITS

LEVEL OF RISK AND BENEFITMagnitude of effect

Likelihood Minimal Minor Moderate Major Massive

Highly improbable A A B C D

Improbable A B C D E

Very unlikely B C D E E

Unlikely C D E E F

Likely D E E F F

Very likely E E F F G

Extremely likely E F F G G

• For each risk likelihood and magnitude combined to give a rank/ index for decision-making

• A & B negligible; C low; D & E medium to high (may or may not be acceptable); F & G extreme

Commercially available BCAs

EU-ERBIC project

DEALING WITH UNCERTAINTY

There will always be some uncertainty

Context of uncertainty for classical BCAs:• Exposure is hard to control, manage, mitigate• Hazard is permanent, will spread, irreversible

Other considerations:• more data to reduce uncertainty• cumulative effects• time lags• balance of short term benefit vs. long-term risk• population impacts• extrapolation to ‘real world’

Make judgement on the significance of uncertainly

indicates a risk-averse approach}

LESSONS LEARNED FROM RA FOR BCAS

• Important to establish the context and develop meaningful risk hypotheses

• Case-by-case approach• Understand the organisms involved (ecology,

distribution, phenology, behaviour)• Design robust tests with appropriate test

species to make realistic predictions• Careful evaluation of likelihood and magnitude

of consequences for risks and benefits will provide consistency and balance in RA

• Clarity of context around uncertainty• Verify predictions by post-release monitoring

ACKNOWLEDGEMENTS

Colleagues in AgResearch and the Research collaboration ‘Better Border Biosecurity’

Department of ConservationEPA New Zealand

Funding:FRSTMBIE