1080 poison baiting used for the control of vertebrate pest animals - rejection of key threatening process listing

The NSW Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to REJECT a proposal to list ‘1080 poison baiting used for the control of vertebrate pest animals’ as a key threatening process in Schedule 3 of the Act. Rejection of nominations is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Poison baiting for the control of vertebrates using 1080 toxin (sodium fluoroacetate) has occurred in Australia since the 1950s. Carnivores such as foxes and wild dogs are typically targeted with meat baits injected with 1080 or manufactured baits which are a composite of grain, meat-meal and various attractants. Herbivores and omnivores, such as rabbits and pigs, are targeted with a wide variety of baits ranging from grain and fresh produce to manufactured baits.

2. Because 1080 is a slow-acting toxin (>30 min), direct measurement of field mortality is difficult for both target and non-target fauna. Many factors influence whether bait consumption is fatal including 1080 concentration, body mass of the individual, and sensitivity to 1080, which varies among species and geographically (e.g. many species in Western Australia are far less sensitive to 1080 than their eastern counterparts). Sub-lethal doses may hinder reproduction or debilitate animals, making them vulnerable to predation (McIlroy 1981), although field evidence for this problem is not currently available.

3. Secondary poisoning is possible through consumption of undigested bait in the stomach of a poisoned animal. Target species sometimes vomit stomach contents containing high concentrations of 1080, which is then potentially eaten by non-target fauna. Maggots in meat baits can accumulate enough toxin to kill a vertebrate (e.g. insectivorous bird) that picks multiple maggots from the bait. Secondary poisoning has been demonstrated to kill individual non-target animals but no data are available demonstrating that such poisoning can cause significant reduction in the population sizes of native species in NSW (APVMA 2005; Glen  et al 2007; NZERMA 2007).

4. Baits are sometimes designed to discourage consumption or intoxication by non-target species. For instance, meat baits that are very dry hinder consumption by small carnivorous marsupials. Some manufactured baits have all toxin concentrated in the centre so that small animals nibbling the outside are not poisoned. Flavourings and bright colours can be added to herbivore baits to discourage consumption by birds (NZERMA 2007). The loss of 1080 from distributed baits by leaching or microbial degradation is highly variable depending on bait type and environmental factors, but most baits have low toxicity after several weeks in the field (e.g. Fleming and Parker 1991).

5. Protocols for bait distribution vary greatly across NSW (e.g. 2–40 baits per km transect) as do bait types and 1080 dosage. Because baits are often taken by non-target species some baiting programs intentionally distribute high densities. Contravention of baiting guidelines is commonly reported.

6. In NSW, particular concern has been raised for populations of a non-target carnivore, the Spotted-tailed Quoll Dasyurus maculatus, which is affected by baiting for wild dogs and foxes ( e.g. Belcher 1998). Recent studies suggest that the risk posed to quolls by 1080 baits may be much less than previously thought (Körtner and Watson 2005, Claridge and Mills 2007). Although some individuals died from consuming 1080 baits during multiple field trials, there is no evidence that the viability of each population of quolls was significantly affected by these losses.

7. At this time, evidence for the impact of 1080 baiting on non-target populations is largely anecdotal, and refers to individuals rather than population effects. Although risk of 1080 baits to non-target fauna is potentially great and mortality of individuals has been recorded, the available research has provided no convincing data that show significant declines at a population level (e.g. APVMA 2005; NZERMA 2007). Nonetheless, localised impacts on some non-target vertebrate populations are possible ( e.g. McIlroy 1982) which suggests careful program design and monitoring are essential, especially where less conservative baiting protocols are employed.

8. In view of the above the Scientific Committee is of the opinion that ‘1080 poison baiting used for the control of vertebrate pest animals’ is not eligible to be listed as a Key Threatening Process in Schedule 3 of the Act as there is currently no substantive evidence that, in NSW:

(a) it adversely affects threatened species, populations or ecological communities, or

(b) could cause species, populations or ecological communities that are not threatened to become threatened.

Professor Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 18/04/08
Exhibition period: 18/04/08 - 13/06/08

References

APVMA (2005) ‘The reconsideration of registrations of products containing sodium fluoroacetate (1080) and their associated labels. Preliminary review.’ Australian Pesticides and Veterinary Medicines Authority, Canberra.

Belcher C (1998) Susceptibility of the tiger quoll, Dasyurus maculatus, and the eastern quoll,  D. viverrinus, to 1080-poisoned baits in control programmes for vertebrate pests in eastern Australia.  Wildlife Research 25, 33-40.

Claridge AW, Mills DJ (2007) Aerial baiting for wild dogs has no observable impact on spotted-tailed quolls (Dasyurus maculatus) in a rainshadow woodland.  Wildlife Research 34, 116-124.

Fleming PJS, Parker RW (1991) Temporal decline of 1080 within meat baits used for control of wild dogs in New South Wales. Wildlife Research 18, 729-740.

Glen AS, Gentle MN, Dickman CR (2007) Non-target impacts of poison baiting for Predator Control in Australia. Mammal Review 37, 191-205.

Körtner G, Watson P (2005) The immediate impact of 1080 aerial baiting to control wild dogs on a spotted-tailed quoll population. Wildlife Research 32, 673-680.

McIlroy JC (1981) The sensitivity of Australian animals to 1080 poison. I. Intraspecific variation and factors affecting acute toxicity. Australian Wildlife Research 8, 369-383.

McIlroy JC (1982) The sensitivity of Australian carnivorous marsupials to 1080 poison. In ‘Carnivorous Marsupials’. (Ed. M Archer) pp 267-271. (Royal Zoological Society of NSW: Sydney)

NZERMA (2007) Evaluation and review report: reassessment of 1080 (HRE05002). Appendix F: Monitoring effects on target and non-target species following 1080 operations. New Zealand Environmental Risk Management Authority. Accessed on 10 December 2007.