Impacts of 1080-poisoning for possum control on non-target invertebrates (original) (raw)
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New Zealand Journal of Ecology
Artificial refuges and mark-recapture techniques were used to monitor the non-target impacts of handbroadcast application (simulating aerial application) of Wanganui No.7 cereal-based baits containing 0.15% (1500 µg g -1 ) 1080 on populations of weta and other invertebrates in Tararua Forest Park, North Island, New Zealand. Wellington tree weta (Hemideina crassidens) and a cave weta (Isoplectron sp.) were the only species of weta that occupied the refuges. Flatworms, slugs, spiders, harvestmen, amphipods, millipedes, centipedes, cockroaches, and beetles also occupied the refuges. Invertebrate numbers in the refuges were monitored for 12 months before and 4 months after bait application on 22 August 2000. Bait application had no significant impact on the numbers of either species of weta, or on slugs, spiders, and cockroaches, the most numerous other invertebrates occupying the refuges. Bait application also had no effect on the number of individually marked tree weta resighted in the refuges. Few weta or other invertebrates were observed on baits at night. The concentration of 1080 in a cave weta collected alive from a bait, and in a tree weta collected alive from outside an artificial refuge, was less than 10% of the average lethal dose. The results indicate that 1080-poisoning for vertebrate pest control is unlikely to have any negative impact on populations of weta or the other invertebrates monitored.
Wildlife Research, 2011
Context Aerial poisoning using sodium fluoroacetate (1080) is an important but controversial technique used for large-scale control of brushtail possums (Trichosurus vulpecula) and other pests in New Zealand. The technique reliably produces near total kills of possums and rats, provided that many tens of baits (and therefore many tens of individually lethal doses) are sown for each target animal present. Aim The aim of this study was to further refine aerial 1080 poisoning by determining the effect of prefeeding, sowing rate, and sowing pattern on effectiveness. Methods Eighteen experimental treatments comprising all possible combinations of three sowing rates (1, 2, and 5 kg/ha of bait), three frequencies of non-toxic prefeed (0, 1, and 2) and two sowing patterns (parallel and cross-hatched) were applied to each of two forested areas. Treatment effectiveness was assessed from changes in the rate of interference recorded on baited cards for three species: possum, ship rat (Rattus ra...
New Zealand Journal of Zoology, 1999
This study was initiated in response to concerns that vertebrate pest control operations in New Zealand may be having deleterious impacts on invertebrate populations and, secondarily, on insectivorous non-target vertebrate populations. Invertebrates feeding on non-toxic baits of the types used for vertebrate pest control were collected and identified. The bait types were diced carrots and three types of cereal-based baits (No.7, RS5, and AgTech). The study was conducted in two rata/kamahi dominated forests (Bell Hill Scenic Reserve and Kopara Forest, West Coast), in July and September 1996. The most common species found on baits was the ant Huberia brouni (Hymenoptera: Formicidae). Other common taxa were Orthoptera (at least eight species of weta including Zealandosandrus aff. gracilis, Gymnoplectron sp., and Pleioplectron sp.), Coleoptera (at least nine species of beetles including Saphobius nitidulus, Nestrius sp., and Phrynixus sp.), Dermaptera (at least one species of the earwig Parisolabis sp.), Opiliones (at least three species of harvestmen), and Acarina (at least three species of mites). The ants and weta were found predominately on cereal-based baits, and the beetles, earwigs, harvestmen, and mites predominantly on carrot baits. More invertebrates were found on carrot and RS5 cereal-based baits than on the other two bait types, and more on baits at night than during the day. Fewer invertebrates were found on cinnamon-flavoured baits (used for 1080-poisoning of possums) than on plain baits (used for brodifacoum-poisoning of rodents). The number of species and number of individual invertebrates found on baits were a small proportion of the number likely to be present in the forest litter. We predict that vertebrate pest control operations are unlikely to have any longterm deleterious impacts on invertebrate populations. This prediction should be tested by monitoring populations of invertebrate species, found to eat baits, during vertebrate pest control operations. __________________________________________________________________________________________________________________________________
Cost-Effective Strategies for the Sustained Control of Bait-Shy Vertebrate Pests in New Zealand
Proceedings of the Vertebrate Pest Conference, 2006
The brushtail possum is a significant conservation pest and major vector of bovine tuberculosis in New Zealand. Previous control simulation studies have suggested that aerial control with bait containing sodium monofluoroacetate (1080) is the most cost-effective large-scale possum control strategy. However, there is a growing awareness that the survivors of 1080 control can develop 'bait shyness', and this can markedly alter the efficacy of ongoing 1080 control operations. Several alternative toxicants are registered for possum control but all are ground based, differ in their mode of action, and are more expensive than aerial 1080 control. A new possum control simulation model was developed to assist in identifying the most cost-effective control strategy that would achieve a sustained 80% population reduction, given bait-shy behaviour and immigration from adjacent noncontrolled areas. The simulation results indicated that it is possible to achieve a sustained 80% population reduction (over a 10-year period) using a 1080-based control strategy, provided at least 90% of all 'susceptible' possums are killed in each control operation. In the event of an unsuccessful 1080 control operation (i.e., only a 60% kill), cyanide bait plus trapping, or brodifacoum bait provided the most cost-effective strategy of 'mopping up' 1080 bait-shy survivors. However, sufficient numbers of traps must accompany the cyanide bait to ensure that the majority of 1080 bait-shy possums are targeted. Sensitivity analysis indicated that the most important variable influencing the overall success of any control strategies was the rate of re-colonization following control. With the high rates of immigration that are sometimes observed in small forest reserves (i.e., <100 ha), it was not possible to sustain an 80% population reduction using any combination of toxicants. However, higher rates of immigration are probably exceptional and the rate used in these simulations is considered more typical, particularly for moderate-to-large forest stands where most possum control is conducted.
Impacts of aerial application of 1080 on non-target native fauna
Sodium monofluoroacetate (1080) is used by the Department of Conservation (in cereal-based baits) and by Regional Councils (in carrot and cereal-based baits) during aerial poisoning operations for control of possums (Trichosurus vulpecula) in New Zealand. The impacts of these operations on non-target species of birds, bats, lizards, frogs and invertebrates are reviewed, and priorities for further research are recommended. A Research Co-ordinating Group should be established to implement these recommendations.
The use of different types of toxic bait for sustained control of possums
Proceedings of the New Zealand Plant Protection Conference
Assessment of six types of toxic bait in replicated field trials demonstrated that baits containing 0.15% 1080 were the most costeffective for initial control of possum populations. Possums surviving an initial exposure to either 1080, cyanide, or cholecalciferol baits would not eat lethal amounts of bait containing another fast-acting toxicant during the following 2.5 months. However, 'shyness' to 1080 or cholecalciferol baits in possums surviving initial control was overcome by using a slowacting anticoagulant poison during maintenance control. Sustained control of possums is currently most cost-effective if baits containing 0.15% 1080 are followed at least 2 months later by baits containing 0.002% brodifacoum. Unlicenced operators can similarly achieve sustained control of possums at very low densities by using brodifacoum baits 2 months after initial control is undertaken with baits containing cholecalciferol.
Invertebrates feeding on baits used for vertebrate pest control in New Zealand
New Zealand Journal of Ecology
This study was initiated in response to concerns that vertebrate pest control operations in New Zealand may be having deleterious impacts on invertebrate populations and, secondarily, on insectivorous non-target vertebrate populations. Invertebrates feeding on non-toxic baits of the types used for vertebrate pest control were collected and identified. The bait types were diced carrots and three types of cereal-based baits (No.7, RS5, and AgTech). The study was conducted in two rata/kamahi dominated forests (Bell Hill Scenic Reserve and Kopara Forest, West Coast), in July and September 1996. The most common species found on baits was the ant Huberia brouni (Hymenoptera: Formicidae). Other common taxa were Orthoptera (at least eight species of weta including Zealandosandrus aff. gracilis, Gymnoplectron sp., and Pleioplectron sp.), Coleoptera (at least nine species of beetles including Saphobius nitidulus, Nestrius sp., and Phrynixus sp.), Dermaptera (at least one species of the earwig...