1. Background
2. Methodology
3. Sustainable Land
Management: the Rabbit Problem
4. The Goals and
Objectives of an RCD Release Programme
5. The
Effectiveness and Suitability of RCD as a Biocontrol Agent
6. Unintended Impacts: Mitigation of
Risk
7. Economic and Financial
Considerations
8. Summary
O 3-1-7
28 February, 1997
Dr Barry O’Neil
Chief Veterinary Officer
Ministry of Agriculture
PO Box 2526
WELLINGTON
Dear Dr O’Neil
APPLICATION TO IMPORT RCD INTO NEW ZEALAND: ISSUES REPORT
Thank you for the opportunity to report on the major issues associated with the importation of Rabbit Calicivirus (RCD) that have been raised by
You have asked us to comment on the major issues associated with the application to introduce RCD that fall within the Ministry’s area of expertise.
The Ministry is responsible for advising the Government on sustainable land management policy and the other key objectives in the Government’s environmental policy. The Ministry is also responsible for the development of and advice on the new organisms policy. In this respect sustainable land management outcomes are a high priority concern for the Ministry, and we have a strong interest in progressing and promoting the best available solutions. In terms of the application to introduce RCD, our role is to ensure that the proposed RCD programme will result in more sustainable land management. Any such programme needs to be subject to a robust environmental assessment process.
To gauge the ability of the RCD to contribute to more sustainable land management we have assessed the Import Impact Assessment (IIA) against six factors which we see as constituting the necessary conditions for programme approval. These are that:
the RCD programme has clearly defined and measurable goals;
the RCD programme will, if successful, make a significant contribution to sustainable land management;
the consequential impacts of RCD are identifiable and reasonably able to be mitigated;
the risks and uncertainties are identified and acceptable in terms of scale and distribution;
there are no readily available alternatives with lower cost or risk of consequential impacts; and
if the risks are high, these are balanced by the urgency and essentiality of the RCD programme.
In assessing these factors our comments address the IIA, and reflect our reading of the Analysis of Submissions prepared by Taylor Baines and the submissions themselves. Examples are provided of submissions that refer to the topics on which we comment.
We also refer you to our earlier comments emphasising that a decision on the introduction of RCD needs to take account of an overall strategic approach to rabbit control and land management - see comments made during the peer review and contained in our letters dated 17 July 1996 and 16 August 1996.
3. Sustainable Land Management: the Rabbit Problem
The lack of a clear quantification or estimation of the damage rabbits cause to the New Zealand environment makes it difficult to assess the impact of the rabbit as a pest. Clearly rabbits cause land degradation by removing vegetation, and consequently reducing soil fertility, and exposing soil to erosion. Where there are high rabbit densities, the cost of control is an important element of a farmer’s overall management costs.
In terms of the environmental impact of the rabbit as a pest, we have previously remarked that high rabbit numbers are only one of a number of factors which have contributed to land degradation (17 July 1996). It is likely that rabbits are, at least in part, a symptom of the pressures of grazing by domestic livestock and burning for pastoral purposes because rabbits prefer the more open landscape generated by these activities. Consequently, it is difficult to apportion the damage that can be directly attributed to rabbits in relation to the pressures caused by livestock grazing and burning (e.g. Ministry of Research, Science & Technology submission).
We note that the spatial distribution maps included in the application show that "extreme" and "high" rabbit prone land is limited almost exclusively to the South Island high country. Submitters have questioned whether a relatively localised regional problem, where only a small percentage of actual land area can be regarded as highly susceptible to rabbits, justifies the introduction of a virus which has potentially significant national costs in ecological terms (e.g. NZ Veterinary Association).
4. The Goals and Objectives of an RCD Release Programme
It is important that the goals of the proposed RCD programme are clearly defined so that their achievement can be measured and monitored. The Ministry wishes to be confident that the objectives of the programme will make a significant contribution to sustainable land management.
Submitters have noted that the goal of RCD release in New Zealand is not immediately clear from the application (e.g. Ministry of Research, Science & Technology, Ministry of Commerce). The IIA states:
"The goal of the release of RCD in New Zealand is equivocal because the nature and extent of the rabbit problem vary greatly, and the spread and persistence of RCD are uncertain." (Page 85)
It goes on to say:
"It is hoped that the long term suppression of rabbit populations will be such that widespread poisoning is no longer necessary." (Page 85)
The application also suggests that RCD could result in "improved production values for extensive pastoral systems" (Page 59).
The Ministry does not consider that these statements are a useful expression of the goals and objectives of an RCD programme. We have previously noted the need for a clear statement of the goals of an RCD programme, together with the need for a comprehensive release strategy so that we could assess the ability of RCD to maintain the stated environmental/pastoral goal over time (17 July 1996). We recommended the inclusion of a comprehensive release strategy clearly linking the use of RCD with the adoption of sustainable land management practices, especially in the degraded areas of the South Island high country. We suggested that this might include:
requiring that the restoration of soil and tussock cover be a priority following the use of RCD and the subsequent decline in rabbit numbers; and
specifying how sustainable land management might be achieved (e.g. relevant directions for regional pest management plans and regional land plans).
This is important because, without a comprehensive release strategy there is a risk that RCD will be seen as a "quick fix" option, rather than part of an ongoing and integrated rabbit and land management strategy. Accordingly, we recommended that the applicants, who include the regional councils of the most rabbit prone areas, take up their responsibilities as the authorities responsible for regional pest management strategies by providing a comprehensive RCD management plan. We note that a number of submitters have also called for RCD to be linked to either national or regional pest management strategies that clearly set out the responsibilities for releasing, controlling and financing an RCD programme (e.g. NZ Veterinary Association, Forest & Bird).
As it stands, we do not consider that the current application has adequately addressed these concerns. We appreciate that many supporters of RCD acknowledge the need to use RCD to achieve more sustainable land management (e.g. High Country Committee of Federated Farmers). However, there needs to be a clear statement of responsibilities outlining how RCD would be used in conjunction with other control techniques and land management practices to achieve sustainable land management. This would enable the public to have confidence that RCD will benefit the New Zealand environment.
5. The Effectiveness and Suitability of RCD as a Biocontrol Agent
The lack of information on the use of RCD as a biocontrol agent is referred to by many submitters and, most notably by the Ministry of Research, Science and Technology in their submission which notes that "models of the impact of RCD in New Zealand and Australia did not show RCD persisting". The report then states:
"It is not possible to be certain of the behaviour of RCD in New Zealand because many of the epidemiological factors are unknown. RCD might become endemic, or alternatively it might be used as a biocide. This would not be a matter of choice but would depend on the behaviour of RCD under New Zealand conditions."
and "Since the persistence of rabbit calicivirus and the speed of development of resistance in rabbits and attenuation of [RCD] are unknown, predicting the long-term effect of RCD release is difficult."
As noted in the analysis of submissions the main areas of concern are
no vector for RCD has been established;
there is scientific uncertainty surrounding the method in which RCD is transmitted; and
there is uncertainty about the persistence and spread of RCD in the New Zealand environment.
This lack of information hinders objective decision-making and makes it extremely difficult to assess the potential efficacy of RCD as a biocontrol agent for New Zealand. The most we can do is look to the Australian experience with RCD and assume that there might be some similarities in the way RCD behaves in New Zealand.
Here we note that the Australian Bureau of Resource Sciences has said that: "The most likely scenario for the effect of RCD upon Australia’s wild rabbit population is a fluctuating, patchy decline of uncertain duration and level." (appendix to submission 673) In the light of this uncertainty a number of submitters (e.g. Landcorp Farming Ltd, Forest & Bird) have called for the applicant group and Government agencies to monitor RCD in Australia so that New Zealand can take full benefit from the Australian experience.
6. Unintended Impacts: Mitigation of Risk
We endorse the conclusion drawn by the Ministry of Research, Science and Technology that: "Given the difficulty of predicting the behaviour of RCD in rabbits in New Zealand, the consequential effects are also difficult to predict". However, as we have noted, the risks associated with RCD should not be discounted just because they are uncertain (17 July 1996).
The risks fall into two categories, risks to human health (we are unable to comment on these) and environmental/ecological risks. Our assessment of the environmental / ecological risks and their significance is as follows:
direct threats to other species through mutation and host switching - probably low, but not quantified risk; the Ministry of Research, Science and Technology recommends further analysis and comparison with other types of calicivirus such as feline calicivirus which has a longer history of study than RCD;
indirect threats to other species through prey switching and changes in predator guilds leading to increased predation pressure on native fauna - not quantified but potentially significant risk which requires further research (Department of Conservation); this risk is increased by the lack of a comprehensive post-release strategy; and
increased woody weed growth - there has been little analysis of this (Ministry of Commerce); the extent of risk will depend on the response by land managers to RCD epidemics (Department of Conservation).
We acknowledge that these risks are very difficult to quantify and predict until further research is undertaken. Nevertheless, we are concerned that the proposed programme is not clear about risk of unintended impacts and how the adverse environmental impacts of RCD will be mitigated. We note that a number of submitters are adamant that, in the face of incomplete information about RCD, the precautionary principle must prevail and that RCD should not be introduced until there is greater certainty about its likely behaviour in New Zealand and any consequential effects such as prey switching and risks to human health (e.g. Ngai Tahu Maori Law Centre).
A number of submissions point out that there is no clarification of the Crown’s liability, in particular for long term risks. We believe this issue should be addressed.
7. Economic and Financial Considerations
As already pointed out (17 July 1996) the lack of analysis of the relative costs and benefits of introducing RCD makes it difficult to gauge the costs of and alternatives to current control measures. We suggested a reasonably impartial weighting of the costs and benefits (both monetary and non-monetary) of RCD involving four or five different scenarios ranging from no expenditure on rabbit control to an accidental or illegal introduction of RCD. The estimated risk posed by each scenario could then be assessed against the cost of reducing the risk to an acceptable level. We would then be in a position to evaluate the relative costs and benefits of each option.
The lack of a comparative assessment of the costs and benefits of different control measures has been noted by a number of submitters. Also, there is no consideration of alternative techniques. For example, fertility control for rabbits and whether or not this would have a lower risk of unintended impacts. We note that the absence of such information has lead the Ministry of Commerce to conclude that, because alternatives to the introduction of RCD have not been detailed and the objectives of releasing RCD have not been quantified "the ultimate success or otherwise of the proposed action is incapable of assessment".
We suggest that the most robust evaluation of the costs and benefits of introducing RCD is that provided by Brown Copeland and Co and contained in appendix O of the IIA. This concludes that the net financial benefits to the nation with the introduction of RCD are not likely to be significant, but benefits to land owners in rabbit prone areas would be significant.
We are concerned that the issue of financial responsibility for mitigating any consequential effects of RCD has not been addressed. This would include the costs of carrying out predator and weed control and monitoring following an introduction of RCD. We note that the Department of Conservation has estimated the cost of mitigating measures as $2.45 million in the first year. We believe that these costs should probably be borne by those who benefit from RCD and/or the applicant group/regional councils. Certainly, this issue needs to resolved at the earliest opportunity.
The Ministry wishes to be confident that the introduction of RCD would effectively contribute to more sustainable land management. Our principal concerns relate to the uncertainties surrounding the effectiveness of the programme and the environmental/ecological risks of unintended impacts. We are not in a position to make a judgement on other factors (such as risk to human health) which are being considered by other agencies.
We are unable to quantify the environmental impact of the rabbit problem and assess this against the risks, which are uncertain. Therefore, at this point in time, the Ministry’s key concerns are that:
the applicants have not provided a comprehensive release programme with clear responsibilities for the on-going management of RCD to ensure sustainable land management;
there is not yet convincing evidence that RCD will be an effective long term biocontrol agent against rabbits; and
there is inadequate information on the environmental risks of unintended impacts of RCD.
Contact for Enquiries
Manager, Strategic Science Team
MAF Biosecurity New Zealand
PO Box 2526
Wellington
NEW ZEALAND
Phone: +64 4 894 0115
Fax: +64 4 894 0731
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