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Malvern East, Australia

Marks C.A.,Nocturnal Wildlife Research Pty Ltd | Obendorf D.,Veterinary Pathologist | Pereira F.,The Interdisciplinary Center | Edwards I.,Padded Traps Ltd | Hall G.P.,University of New England of Australia
Journal of Applied Ecology | Year: 2014

Summary: Models used for resource allocation in eradication programmes must be based on replicated data of known quality and have proven predictive accuracy, or they may provide a false indication of species presence and/or distribution. In the absence of data corroborating the presence of extant foxes Vulpes vulpes in Tasmania, a habitat-specific model based upon mtDNA data (Sarre et al. 2012. Journal Applied Ecology, 50, 459-468) implied that foxes were widespread. Overall, 61 of 9940 (0·6%) surveyed scats were assigned as mtDNA fox positive by the fox eradication programme (FEP). We investigated the spatiotemporal distribution of the 61 mtDNA-assigned fox scats and modelled the probability of replicating scat detection in independent surveys using detection dogs based upon empirically derived probabilities of scat detection success obtained by the FEP using imported fox scats. In a prior mainland study, fox genotypes were recurrently detected in a consecutive four-day pool of scats. In Tasmania, only three contemporaneously collected scat pairs of unknown genotype were detected by the FEP within an area corresponding to a conservatively large mainland fox home range (639 ha) in a decade. Nearest neighbour pairs were widely spaced (mean = 7·0 km; circular area = 153 km2) and generated after a mean of 281 days. The majority of assigned mtDNA positive scats were found in urban and peri-urban environments corresponding to small mainland fox home ranges (30-45 ha) that imply higher scat density and more certain replication. Using the lowest empirically determined scat detection success for dogs, the failure to replicate fox scat detection on 34 of 36 occasions in a large (639 ha) home range is highly improbable (P = 0·00001) and suggestive of Type I error. Synthesis and applications. Type I error, which may have various sources, should be considered when scat mtDNA data are few, accumulated over many years, uncorroborated by observations of extant specimens, inadequately replicated in independent surveys within an expected spatiotemporal scale and reported in geographically isolated environments unlikely to have been colonized. © 2014 The Authors. Journal of Applied Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. Source


Marks C.A.,Nocturnal Wildlife Research Pty Ltd | Obendorf D.,Veterinary Pathologist | Pereira F.,The Interdisciplinary Center | Edwards I.,3777 Gordon River Road | Hall G.P.,University of New England of Australia
Wildlife Society Bulletin | Year: 2014

Despite the absence of direct observation of live foxes in the Tasmanian environment, a recent study concluded that foxes are now widespread on the island and proposed a habitat-specific model incorporating 9 cases of physical evidence presumed to confirm their unique presence. We briefly review the history of fox incursions into Tasmania and then assess the quality of putative physical evidence against a defined evidentiary standard. Overall, 14 of 17 incidents described since 1998 were associated with between 1 and 4 criteria indicative of unreliable data or were not associated with adequately documented physical evidence. Anonymous and anecdotal information was fully or partially relied upon in 10 of 17 cases and of these 5 were widely acknowledged to be hoaxes. We conclude that opportunistically acquired evidence is a poor substitute for data obtained by properly designed and independent wildlife surveys for confirming unique fox incursions and as the basis of ecological models predicting true habitat-specific fox distribution. Species rarity decreases the reliability of wildlife surveys and population models; thus validation of unique incursions in particular requires appropriate rigor in evidentiary standards and data quality. Precautionary management that may be considered in response to uncertain information, or opportunistically collected specimens of doubtful provenance, does not imply that such information should be treated as scientific data. We suggest that an eradication program is justified as a precautionary measure only after rigorous qualitative analysis reveals data capable of rejecting the null hypothesis that the species of interest is absent. © 2014 The Wildlife Society. Source


Goncalves J.,University of Porto | Marks C.A.,Nocturnal Wildlife Research Pty Ltd | Obendorf D.,7 Bonnington Road | Amorim A.,University of Porto | Pereira F.,The Interdisciplinary Center
Conservation Genetics Resources | Year: 2014

The European red fox (Vulpes vulpes) is a highly adaptable predator indigenous to the northern hemisphere. However, in Australia the red fox is a widespread exotic predator that has contributed to the decline and extinction of several native species. Here we describe a multiplex PCR assay for the molecular identification of the red fox. The identification is achieved by the generation of a diagnostic profile combining the lengths of mitochondrial ribosomal RNA (rRNA) gene regions amplified using highly conserved PCR primers. The method was tested in DNA samples from 17 species, including in mixtures. Our results demonstrate that the red fox has a unique combination of fragment lengths determined by capillary electrophoresis that can be used for its unambiguous discrimination from common domestic and wild species. © 2014, Springer Science+Business Media Dordrecht. Source


Marks C.A.,Nocturnal Wildlife Research Pty Ltd
Animal Welfare | Year: 2010

This paper sought to determine whether common haematology and blood biochemistry values might assist in determining the relative welfare outcomes arising from the capture of red foxes (Vulpes vulpes) by treadle-snares, Victor Soft Catch® (VSC) #3 traps, cage traps, netting and sampling by shooting. Compared to all other capture methods and shooting, treadle-snared foxes had significantly higher mean albumin (ALB), creatine kinase (CK), red cell count (RCC), neutrophil to lymphocyte (N:L) ratio, sodium (Na), total protein (TP), white cell counts (WCC) and lower glucose (Gl). Treadle-snares were also associated with higher chloride (Cl), haemoglobin (Hb) and packed cell volume (PCV) than cage trapping and netting. Treadle-snares produced indicators of possible muscle damage, exertion and dehydration compared to cage and VSC traps. Cage trapping and netting produced lower indications of exertion, possible muscle damage and dehydration compared to both treadle-snares and VSC traps. These data do not support previous conclusions that due to similar injury scores, treadle-snares and VSC traps produced equivalent welfare outcomes. In restraining traps, injury and death sustained during capture are end-points of poor trapping welfare. Monitoring stress using physiological indicators allows the comparison of the relative potential for different capture techniques to cause pathological and pre-pathological states. As the response of physiological indicators to stress is not independent of time, accurate data on the duration of captivity and the relative intensity of struggling behaviour should be routinely collected when assessing the comparative humaneness of different trap devices. © 2010 Universities Federation for Animal Welfare. Source


Marks C.A.,Nocturnal Wildlife Research Pty Ltd | Edwards I.,3777 Gordon River Rd | Obendorf D.,7 Bonnington Road | Pereira F.,The Interdisciplinary Center | Hall G.P.,University of New England of Australia
Ecological Management and Restoration | Year: 2014

Anecdotal reports in 2001 suggested that the European Red Fox (Vulpes vulpes) had been deliberately released in Tasmania and thereafter an eradication programme using buried fluoroacetic acid (1080) baits was believed to be a necessary precautionary action until mid-2013. Prerequisites for the successful eradication of foxes relate to the scale of the undertaking and the ability to collect in situ data such as the distribution and abundance of the target population and measures of the efficacy of the control technique. Previously, 1080 baiting has demonstrated only limited potential as a fox eradication technique on islands when used on a scale between 685 and 2141 times smaller than Tasmania. In the absence of empirical monitoring data confirming the distribution or abundance of extant foxes, buried baiting was targeted to specific landscapes believed to be preferred by foxes. No empirical data was collected concerning the in situ effectiveness of baiting in Tasmania, yet an a priori assumption of lethal efficacy was extrapolated from four heterogeneous mainland studies to suggest that foxes would have only a 0.23 probability of surviving each bait treatment. We show that these studies were unrepresentative of Tasmanian baiting methods used and influenced by imprecise fox population surveys and misreported data. Overall, in the absence of key population monitoring and efficacy data, the 'precautionary' baiting strategy adopted did not have a realistic potential to eradicate fox incursions in Tasmania, nor is it an appropriate risk management strategy for other large offshore Australian islands. Contingency plans to counter fox incursions on offshore islands must address the currently inadequate technical capacity to reliably detect and monitor low-density fox populations, which is an essential component of successful fox eradication. © 2014 Ecological Society of Australia and Wiley Publishing Asia Pty Ltd. Source

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