6 results on '"Hall, Graham"'
Search Results
2. Did 'precautionary' 1080 baiting have a realistic potential to eradicate Red Fox ( Vulpes vulpes) in Tasmania without in situ monitoring data?
- Author
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Marks, Clive A., Edwards, Ivo, Obendorf, David, Pereira, Filipe, and Hall, Graham P.
- Subjects
RED fox ,FLUOROACETIC acid ,FLUOROACETATES ,SURVEYS - Abstract
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. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
3. The dispersion and detection patterns of mt DNA-assigned red fox Vulpes vulpes scats in Tasmania are anomalous.
- Author
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Marks, Clive A, Obendorf, David, Pereira, Filipe, Edwards, Ivo, Hall, Graham P, and Lukacs, Paul
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MITOCHONDRIAL DNA ,RED fox ,ANIMAL droppings ,DATA quality ,RESOURCE allocation ,DOGS ,SPECIES distribution - Abstract
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 mt DNA 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 mt DNA fox positive by the fox eradication programme ( FEP)., We investigated the spatiotemporal distribution of the 61 mt DNA-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 km
2 ) and generated after a mean of 281 days., The majority of assigned mt DNA 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 mt DNA 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. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
4. Opportunistically acquired evidence is unsuitable data to model fox ( Vulpes vulpes) distribution in Tasmania.
- Author
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Marks, Clive A., Obendorf, David, Pereira, Filipe, Edwards, Ivo, and Hall, Graham P.
- Subjects
RED fox ,ZOOGEOGRAPHY ,WILDLIFE management ,ANIMAL populations ,ANIMAL ecology - Abstract
ABSTRACT 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. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
5. Genetic structure of introduced European fallow deer ( Dama dama dama) in Tasmania, Australia.
- Author
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Webley, Lee S., Zenger, Kyall R., Hall, Graham P., and Cooper, Desmond W.
- Subjects
FALLOW deer ,SPECIES ,ANIMAL genetics ,WILDLIFE management ,MICROSATELLITE repeats ,POPULATION genetics - Abstract
European fallow deer are an introduced species classified as partly protected wildlife in Tasmania, Australia. Current management practices are primarily governed under the Quality Deer Management regime, in which animals are harvested during designated hunting seasons. Among populations, prominent morphological differences have been reported; however, the genetic relationship of these populations has until now been poorly understood. Representative animals were sampled from three key areas across their range and genotyped at ten polymorphic microsatellite loci to investigate genetic diversity, population structure, and genetic bottlenecks. Allelic richness was low in all three populations and ranged between 2.20 and 2.49 alleles/locus. A genetic bottleneck was detected in two of the three populations ( P < 0.001). Population differentiation was evident between Lake Echo and Benham (q = 0.122; P < 0.001) and Benham and Connorville (q = 0.110; P < 0.001), but not between Lake Echo and Connorville (q = 0.0235), with individuals being identified as belonging to two genetic clusters. The pattern of population differentiation from the three study populations suggests that deer from the western region of their range are genetically distinct to those from the eastern region. This correlates with morphological variation within Tasmanian fallow deer, in which differences between the regions maybe attributable to geographical barriers. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
6. Is tooth wear a reliable means of aging wild European fallow deer in Tasmania, Australia?
- Author
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Hall, Graham P., Murray, Peter J., Byrne, Matthew J., and Lisle, Allan T.
- Subjects
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FALLOW deer , *CEMENTUM annuli , *TOOTH abrasion - Abstract
The tooth eruption and wear (TEW) technique for aging wild European fallow deer ( Dama dama dama) in Tasmania, Australia has been in use for >15 yr, but it is also subjective and relies on the skill of the assessor and their assumptions of tooth wear. Deer managers and hunters have suggested that the TEW patterns observed in Tasmania are not consistent with age predictions of deer based on male antler growth. The cementum annuli (CA) technique provides a more objective assessment of age, but is more costly to perform. Our objective was to examine the relationship between the TEW and CA techniques for estimating the age of wild fallow deer in Tasmania. A game manager experienced in the use of the TEW technique assigned 300 deer jawbones collected from 3 sites during the 2001-2006 hunting seasons in Tasmania to different age categories. We conducted preliminary trials to develop a protocol that reliably exposed the CA in incisor teeth. Finally, we compared the ages determined by both methods. The preliminary trials successfully developed a protocol to use incisor teeth for reliably assessing CA. The CA technique gave a higher putative age than the TEW technique, though the magnitude of this result was dependent on location. The amount of soil ingested by the animals, and whether the animals mainly browsed or grazed were possible reasons why tooth wear varied between locations. Whilst the CA method is effective at indicating the age of wild deer, the method should be proven against known-aged deer before being offered as a definitive measure of age. Managers should be clear in their objectives whether they require an approximate guide to age or an objective measure of age before deciding on which method to use. © 2011 The Wildlife Society. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
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