Effects of the aerial application of 1080 to control pest mammals on kea reproductive success

Kemp, J. F.; Mosen, Corey; Elliott, Graeme; Hunter, Christine M.

doi:10.20417/nzjecol.42.28

Cited by 12 publications

(21 citation statements)

References 29 publications

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“…Rat abundance is particularly high when seed abundance is high as well but stays high for about 15 months before it falls back to the pre-mast level. This is in agreement with what is known from data (Elliott and Kemp 2016;Kemp et al 2018).…”

Section: Generalist Consumersupporting

confidence: 93%

“…A pure predator-prey relationship between rats and seeds would lead to a delayed peak in rat abundance, which would decrease again when seeds degrade. Conversely, data show that rat abundance is high between 15 and 20 months after a year with high seed fall (Elliott and Kemp 2016;Kemp et al 2018). This is because the diet of ship rats also depends implicitly on beech seeds (links 2 and 3 in Fig.…”

Section: Generalist Consumermentioning

confidence: 99%

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The necessity of tailored control of irrupting pest populations driven by pulsed resources

et al. 2020

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Resource pulses are widespread phenomena in diverse ecosystems. Irruptions of generalist consumers and corresponding generalist predators often follow such resource pulses. This can have severe implications on the ecosystem and also on the spread of diseases or on regional famines. Suitable management strategies are necessary to deal with these systems. In this study, we develop a general model to investigate optimal control for such a system and apply this to a case study from New Zealand. In particular, we consider the dynamics of beech masting (episodic synchronous seed production) leading to rodent outbreaks and subsequent stoat (Mustela erminea) irruptions. Here, stoat control happens via secondary poisoning. The results show that the main driver of the optimal control timing (June) is the population density of the control vector. Intermediate control levels are superior to higher levels if the generalist consumer is necessary as a control vector. Finally, we extend the model to a two-patch metapopulation model, which indicates that, as a consequence of the strong vector dependence, a strategy of alternating control patches yields better results than static control. This highlights that besides control level, also the design impacts the control success. The results presented in this study reveal important insights for proper pest management in the New Zealand case study. However, they also generally indicate the necessity of tailored control in such systems.

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Section: Generalist Consumersupporting

confidence: 93%

Section: Generalist Consumermentioning

confidence: 99%

The necessity of tailored control of irrupting pest populations driven by pulsed resources

et al. 2020

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“…As such, kea are more likely than arboreal birds to encounter 1080 pellets and may be more likely than specialist feeders to eat them, thus giving rise to a potentially high negative impact from non target mortality. However, positive consequences of aerial 1080 for kea have also been reported (Kemp et al 2018), attributable to the control of invasive exotic predators, particularly stoats (Mustela erminea), which die from secondary poisoning (Murphy et al 1999). To balance this positive impact against non-target 1080 poisoning risk, and to find risk mitigation pathways, requires improved quantification of risk and an understanding of its spatial and temporal variability.…”

Section: The Kea a Unique Bird With Positive And Negative Responses mentioning

confidence: 99%

“…6). Given the high magnitude of benefits from predator control measured for kea and other species with similar nesting ecology, such as kākā and whio (Hymenolaimus malacorhynchos) (Moorhouse et al 2003;Whitehead et al 2008;Kemp et al 2018), we expect to see strong kea population growth resulting from long term aerial 1080 programmes in remote areas.…”

Section: Utility Of Estimates and Extrapolation To Other Sitesmentioning

confidence: 99%

Kea survival during aerial poisoning for rat and possum control

Kemp¹,

Mosen²,

Elliott³

et al. 2019

NZJE

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The kea (Nestor notabilis) is a highly intelligent and adaptable omnivorous New Zealand parrot. These traits potentially put kea at risk of poisoning during vertebrate pest poisoning operations. However, as kea fall prey to introduced pests, they also gain from pest control, creating a cost-benefit situation. Pest control in kea habitat is mainly by aerial 1080, the distribution of sodium fluoroacetate poison pellets by helicopter. Understanding the net outcome for kea of this pest control method is extremely important because kea are endangered and aerial 1080 use is controversial. We use 222 monitoring cases of individually marked kea at 19 aerial 1080 operations to model kea survival of aerial 1080 operations with respect to five variables. Proximity to human-occupied sites where kea scrounge human food was inversely related to survival; the odds of survival increased by a factor of 6.9 for remote kea compared to those that lived near scrounging sites. High survival in remote areas is explained by innate neophobia and a short field-life of prefeed baits, which together preclude acceptance of poison baits as familiar food. Elevated risk to kea living near scrounging sites is explained by learned neophilia, possibly exacerbated by lead poisoning. Survival was also related to the history of aerial 1080 treatment at a site; the odds of survival increased by a factor of 21.3 at sites with repeated operations compared with first time treatments. This effect is possibly due to selection for neophobic phenotypes. We suggest that 1080 poisoning risk management for kea should focus on reducing human food availability through an advocacy campaign. If most kea have not been fed by humans, then the long term outcome of the South Island aerial 1080 programme should be positive for the kea.

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“…Managers aim to minimise the risks to non-target native species, and this is generally successful (Veltman & Westbrooke 2011), at least in the sense of ensuring that the benefits of increased recruitment of native species as a result of reduced predation outweighs any immediate losses from the baiting (e.g. Kemp et al 2018). Arguably, there has been less concern about the killing of non-target species such as introduced birds (Morriss et al 2016) and larger introduced mammals, including deer (Nugent et al 2001;Veltman & Parkes 2002).…”

Section: Introductionmentioning

confidence: 99%

Effects of aerial 1080 operations on deer populations in New Zealand

Morriss¹,

Parkes²,

Nugent³

2020

NZJE

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Aerially distributed baits containing sodium fluoroacetate (1080) are used in New Zealand for smallmammal pest control over an average of about 600 000 ha each year. This can also kill non-target species, including deer. This incidental mortality of deer generates antipathy to 1080 amongst many hunters, adding to the broader opposition to aerial 1080. Hunter opposition to 1080 baiting has also prompted the development of deer-repellent 1080 bait formulations. Historical estimates of deer mortality varied widely but were sometimes high. However, a recent study showed no adverse impact of 1080 on red deer sighting rates in one area and suggested that modern baiting protocols and frequency may have reduced the risk to deer. Here we provide a broader review of deer mortality observed in 26 aerial 1080 operations (or part operations) conducted since 1999. The estimated mortality of deer ranged from 0% to 100%. Overall, 42%, 38% and 20% of operations were classed as having low (0 to 33%), moderate (34 to 66%) or high (67 to 100%) impacts on deer populations, respectively. Adult males were found dead less often than adult females and all other age/sex classes, suggesting that by-kill risk might sometimes be inversely related to body size. Lower sowing rates (0.25-1.5 kg ha −1) more often resulted in low deer by-kill than higher sowing rates (2.0-3.1 kg ha −1), but there was no indication that using larger (12 g) rather than smaller (6 g) baits increased deer mortality. There was some indication that mortality may be lower where 1080 operation had been repeated within 5 years, possibly because of learned bait aversion in survivors of previous operations. The determinants of incidental mortality of deer are complex and somewhat unpredictable, and some deer are likely to be killed in most if not all operations, irrespective of the baiting strategy. We recommend formally planned experiments (rather than gathering often informal observations as summarised here) to assess whether deer mortality is significantly reduced when low sowing rates and/or short-interval repeat baiting is used, and (if so) whether this jeopardises efficacy in possum and rat control.

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Effects of the aerial application of 1080 to control pest mammals on kea reproductive success

Cited by 12 publications

References 29 publications

The necessity of tailored control of irrupting pest populations driven by pulsed resources

The necessity of tailored control of irrupting pest populations driven by pulsed resources

Kea survival during aerial poisoning for rat and possum control

Effects of aerial 1080 operations on deer populations in New Zealand

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