Evaluating and predicting risk to a large reptile (Varanus varius) from feral cat baiting protocols

• Published in: Biological invasions Vol. 15; no. 8; pp. 1653 - 1663
• Main Authors: Jessop, Tim S., Kearney, Michael R., Moore, Joslin L., Lockwood, Tim, Johnston, Michael
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2013; Springer; Springer Nature B.V
• Subjects: Activity patterns; Amphibia. Reptilia; Animal populations; Animal, plant and microbial ecology; Baits; Biodiversity; Biological and medical sciences; Biomedical and Life Sciences; Climate change; Climate effects; Developmental Biology; Ecology; Felis catus; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Health risks; Indigenous animals; Life Sciences; Lizards; Mammalia; Methods and techniques (sampling, tagging, trapping, modelling...); Mortality risk; National parks; Original Paper; Plant Sciences; Poisons; Predation; Predators; Reptiles; Reptiles & amphibians; Risk factors; Solar radiation; Toxins; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Wildcats; Australia; Introduced predators; Poison baits; Varanid Lizards; Non-target risk; -; Mechanistic niche models; Feral animal; Risk; Modeling; Felis catus; Sauria; Bait; Chemical control; Ecological niche; Varanus varius; Fissipedia; Carnivora; Introduced species; Vertebrata; Mammalia; Mechanistic approach; Reptilia; Predator; Para-aminopropiophenone; Risk management; Non target organism
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-012-0398-3

Control of introduced predators to mitigate biodiversity impacts is a pressing conservation challenge. Across Australia feral cats ( Felis catus ) are a major threat to terrestrial biodiversity. Currently feral cat control is hindered by the limited utility of existing predator baiting methods. Further proposed control methods include use of the novel poison para-aminopropiophenone (PAPP) which may present a hazard to some native animal populations. Here we used experimental and predictive approaches to evaluate feral cat bait take by a large native Australian predatory reptile the Lace monitor ( Varanus varius ). These lizards would be expected to readily detect, ingest and consume a lethal dose (depending on toxin) from surface-laid baits intended for feral cat control if a precautionary approach was not adopted when baiting. We modelled V. varius bait take using experimental and predictive biophysical modelling approaches to evaluate temporal effects of climate variables on V. varius activity and hence potential for bait removal. Finally we conducted a pre-PAPP baiting site occupancy assessment of V. varius within Wilson Promontory National Park (WPNP) to provide a basis for monitoring any longer term population effects of cat baiting. V. variu s removed 7 % of deployed baits from 73 % of bait stations across another study area in Far Eastern Victoria. Daily bait removal was positively correlated with maximum temperature and solar radiation. Biophysical modelling for Far Eastern Victoria predicted that maximum temperatures <19.5 °C prevented V. varius activity and hence opportunity for bait removal. V. varius in WPNP was undetectable suggesting aerial baiting posed limited hazard to this species at this location. Depending how climate influences annual activity patterns and the specific poison, surface-laid baits could pose a significant mortality risk to V. varius . However, use of biophysical models to predict periods of V. varius inactivity may provide a novel means to reduce non-target bait take by this predator.