Evaluating the potential impacts of invasive species

1. Evaluating the potential impactsof invasive species Chris Baddeley Policy Manager Biosecurity New Zealand

2. Overview Purpose of evaluation Method of evaluation Presentation of results Examples • Painted apple moth • Didymo • Other New Zealand examples

3. Purpose of impact evaluation Contributes to decisions on: • whether to respond to a new or existing pest • the scale of any response Forms a key part of the business case for new funding from Government (or industry) for a pest response

4. Purpose of impact evaluation In New Zealand pest response decisions based on: • technical feasibility • economic justification • priority for action Impact evaluation needed to help determine economic justification and priority for action. Also used for communications purposes.

5. Method of evaluation Assess quantifiable pest impacts in the absence of Government intervention (to determine potentially avoidable costs) Develop scenarios around the likely range of impacts. Key factors are: • any likely limits on geographical spread • likely rate of spread • impacts by sector

6. Methods of evaluation Research what is known about the pest (often not a lot for new invaders) Use experts panels to: • bridge knowledge gaps (best expert opinion) • provide advice/opinions on likely rate of spread and geographical limits to spread • develop scenarios of potential sector impacts • form expert views on likely pest impacts (forecasting methods such as Delphi process)

7. Methods of evaluation Also use expert panels to: • form views on feasible options for response • form views of likely effectiveness of treatments Some requirements for an expert panel: • knowledge of all affected sectors • expertise in all relevant disciplines • effective teamwork, listening, building on views of others • no conflicts of interest/maintain confidentiality

8. Methods of evaluation Impacts can be: • reduced productivity • damage to natural values (eg. wildlife) • damage to social values (eg. recreation and amenity) • new or increased pest treatment costs • the need to adapt to the pest (eg. resistant crops, less preferred species) • increased management costs Generally exclude impacts that are too small or too uncertain from numerical assessment (including intangibles). 15

9. Methods of evaluation Good resource information is the key to reliable estimation of impacts • forest estate models or inventories • urban trees databases • agricultural and horticultural statistics • commodity values and trade data • value mapping Also information on likely adaptive behaviour by industry, landowners and the public

10. Methods of evaluation Can undertake some short-term research to gain further information: • host plant testing • life-cycle modeling • ecological research • dispersal rates (sterile insects release, pheromone development)

11. Presentation of results for decision-making Impacts generally determined as a stream of costs stretching into the future Impacts generally presented as a “present value” (discounted). Need to determine time-scale for assessment. Options include: • point where additional impacts are not material • a pre-determined time (investment return period) • time until pest occupies is full potential range • time until the pest is next expected to establish (re-incursion)

12. Presentation of results for decision-making Results can be expressed as: • present values over given period (eradication) • annual value once range fully occupied (on-going management). Also: • sensitivity analysis used to show influence of different assumptions • inclusions and exclusion need to be clearly stated along with any key qualitative information

13. Example – Painted Apple Moth (Teia anartoides) Limits on geographical spread None Rate of spread: Throughout Auckland region in ten years Throughout rest of New Zealand in fifteen years Impacts modeled • urban households (additional spending on spraying) • urban golf courses and school ground (additional spending on spraying) • public land in urban areas (accelerated tree removal and replacement) • plantation forests (spraying costs and reduced growth rate) • horticulture – apples (increased spraying)

14. Example – Painted Apple Moth Distribution of present value total impacts 2002/03 to 2021/22: New Zealand

15. Example – Painted Apple Moth Impacts not modelled (small or too uncertain) • impacts on natural forests • impacts of soil and water conservation • impacts on market access • impacts on human health

16. Example - Didymo Limits on geographical spread Potentially affects a high percentage of high-order river reaches in all regions Rate of spread: Throughout NZ within 7 years of detection Impacts modeled: • commercial eel fisheries • water intakes • drinking water • local recreation values • tourism expenditure • local and national existence values • existence values associated with endangered native species

17. Example - Didymo

18. Example - Didymo

19. Example - Didymo

20. Example - didymo Impacts not assessed: • cultural values including customary fisheries • alluvial gold mining • exports of used fishing and boating gear • human health (eye irritation and injuries for slipping on rocks)

21. Significant biosecurity incursions – New Zealand examples 1996 - 2006

22. Significant biosecurity incursions – New Zealand examples 1996 - 2006

23. Significant biosecurity incursions – New Zealand examples 1996 - 2006