Dung Beetle Submissions

ERMA New Zealand

PO Box 131

Wellington

12 November 2010

Submission on the application to import and release up to eleven species of dung beetle for use in New Zealand pastureland. (Application Code: ERMA200599)

Dear Sir/Madam,

The Auckland Council (AC) welcomes the opportunity to comment on the application by the Dung Beetle Release Strategy Group to import and release up to eleven species of dung beetle for use in New Zealand pastureland. This submission has been prepared by AC staff, and has not been formally considered by the Council due to the short period of time since it was formed. The Auckland Council doeswish to be heard at a public hearing in support of its submission.

Address for Service:

Auckland Council

Private Bag 92−300

Auckland 1142

Attention:

Jack Craw, Manager Biosecurity, Environmental Services

Tel 09 3662000 ext. 8771

The AC is responsible for a range of functions under the Resource Management Act (RMA) including the preparation and implementation of the Regional Policy Statement, District Plans and the processing of resource consents, as well as a range of other functions under the Local Government Act and Biosecurity Act. Among these functions are several which relate to the current proposal, including:

  • The maintenance of indigenous biological diversity;
  • The management of pests and unwanted organisms;
  • The maintenance and enhancement of the quality of water in water bodies; and
  • Soil conservation.

It is well recognised that run-off contaminated with pastoral animal waste contributes to the degradation of water quality in the area managed by the AC. Conversely, agricultural waste materials contain nutrients that have a value as fertiliser, and applying these wastes to land is generally considered to be a beneficial practice in rural areas. From this perspective, the concept of introducing dung beetles that may reduce nutrient runoff and improve soil fertility is worthy of investigation.

However, it is important that a precautionary approach is taken to releasing new organisms into the New Zealand environment. In its current form, the proposal to release eleven species of dung beetles without controls poses a number of risks that are considered to be unacceptable. The information provided with the application is not substantial or specific enough to be able to fully assess the risks or benefits of the proposed introductions.

The information is rather general and mainly addresses dung beetles as a group, rather than the individual species that are planned to be introduced. The proposal raises numerous questions that it is recommended be answered before the irrevocable risk of introducing the dung beetles is taken. If the benefits of introduction are not quantified and demonstrated to significantly outweigh the risks in New Zealand conditions, the proposal should be declined.

Benefits of introduction

The potential benefits of the species proposed for introduction are not clearly demonstrated. While environmental benefits have occurred as a result of the introduction of dung beetles into Australian pastoral systems, the moisture regime, climate and soils of these areas are very different to New Zealand conditions.

If it is accepted that dung beetles would be beneficial in New Zealand pastoral environments, it is also unclear whether the existing practices of chemical use in animal health management (e.g. drenching) would allow the beetles to thrive in sufficient numbers to actually confer those benefits. If the dung beetles would not survive under typical New Zealand farming management practises, the benefit of introducingthem at all is questionable.

Effects on native fauna and flora

A major gap in the application lies in the information provided about the potential effects on New Zealand’s native fauna of dung beetles, as well as the other decomposers that the introduced dung beetles may compete or interact with. Relatively little is known about the ecology of New Zealand’s native dung beetles. In addition, there are many other insect species involved in decomposition processes in New Zealand indigenous ecosystems, and none of these (e.g. millipedes) is considered in the application. Without better information on the ecology of New Zealand’s existing decomposers, the risks of introducing exotic dung beetles cannot be adequately assessed.

The proposal states that:

We do not expect any impact of exotic dung beetles on native dung beetle as the native species only live in deep forest, while the introduced beetles are limited to open grassland. Thus their habitats are clearly separated and any interaction will be rare and limited to forest margins where livestock dung is present.

The proposal fails to take into account other New Zealand ecosystems where dung beetles and decomposers may occur, such as tussock grasslands. In northern New Zealand, open non-forest ecosystems include dunelands and areas of native heath and scrubland, both of which provide habitat for rare native species. In addition, many of Auckland’s forest habitats are highly fragmented with relatively large areas of ‘edge’. Although degraded, these are often important for maintaining the region’s indigenous biodiversity. Further research should be carried out to determine what interactions the proposed introductions may have with native species in indigenous non-forest and modified forest ecosystems.

Effects on soil and water

If the introduced dung beetles established successfully, the potential effects of incorporating animal dung into soil and reducing nutrient runoff may be beneficial in many pastoral environments. However, the application provideslittle information on how these processes might operate in the range of soils and groundwater environments present in New Zealand. For example, could the action of dung beetles exacerbate nutrient transport and eutrophication of water bodies in catchments with highly permeable soils? Vulnerable sites in the Auckland area include dune lakes on the South Kaipara Peninsula, which have been assessed as being of the highest conservation value. Further afield, Lake Taupo with its pumice soils could be at risk.

The AC promotes and supports other methods of protecting and enhancing Auckland’s aquatic ecosystems, notably by encouraging the restoration of riparian vegetation in agricultural landscapes. The application states that dung beetles have the potential to reduce nutrient inputs into aquatic ecosystems. However, dung beetles would not provide other benefits such as shading, soil stabilisation and erosion control offered by existing revegetation methodologies.

Given that the main benefits of the proposed release concern nutrients and water quality, it would be useful for the application to provide information comparing the risk of beetle introduction against other methods already available for nutrient management. If existing methods of nutrient management were implemented more widely, would the introduction of dung beetles actually be necessary? How would the presence of dung beetles benefit or detract from existing riparian management practises such as revegetation?

Precautionary approach

Four exotic species of dung beetles have previously been introduced to New Zealand grasslands, yet little information is given on the effects that these introductions are having. Before the risk of introducing further species is taken, it is recommendedthat quantitative studies be carried out to determine the effects (both beneficial and adverse) of the species that are already here. This would provide better information to properly assess the risks and benefits of introducing additional species.

The proposed introduction of eleven species at once makes the risks of introduction more complicated and difficult to assess. In addition, simultaneous introductions would make it more difficult to adequately research and monitor the ecological interactions and effects of each of the species in New Zealand environments. It is therefore recommended that much more detailed information provided on each individual species, to give a more suitable level of detail for assessing the risks of introduction.

The proposal to mass release the species nation-wide is completely unacceptable, and is contrary to current national biological control principles. Any approval should specify an experimental approach, in controlled circumstances, so that the actual effects in New Zealand conditions can be properly assessed. The adopted methodology should contain the ability to eradicate beetles from release sites, should adverse effects be demonstrated.

The ability to release suitable exotic organisms into the New Zealand environment is an essential tool for biocontrol and the AC has been closely involved in, and financially supportive of, the release of many such organisms in the past. It is therefore important that the integrity of the process for approving the release of new organisms is maintained at a high level, to preserve public confidence and to defend the capability to import appropriate biocontrol agents in future.

Conclusion

While the potential benefits of introducing dung beetles to New Zealand pastoral landscapes are recognised, the current proposal lacks the level of detailed information necessary to assess the risks and benefits of the individual species with confidence. It is also of concern that there is a lack of knowledge about New Zealand’s existing dung beetles and decomposer fauna, which may be adversely affected by the proposed introductions.

The Auckland Council hereby submits that the proposal be withdrawn and resubmitted with further detail on the matters raised above, so that an accurate assessment of the risks can be made. In the event that the proposed introductions are approved, Auckland Council further submitsthat they are carried out under controlled experimental circumstances, so that the actual effects of the dung beetles can be quantified in New Zealand environments.

Yours faithfully,

Patricia Reade

Chief Operating Officer