Foxes in Tasmania - Update
The issue of foxes in Tasmania is one that has remained high on the Australian Mammal Society’s radar for many years now….and understandably for good reason! The Tasmanian Department of Primary Industries, Parks, Water and the Environment has been managing the eradication program through their Invasive Species Unit, and Dr Stephen Harris has provided us with the following information on the projects progress.
· No physical evidence of fox presence in Tasmania has been collected or noted since 2011. We are hopeful about what this might mean but are conducting a methodical approach to determine absence/presence on the basis of several techniques.
1. The first is landscape scale monitoring using detector dogs to systematically survey the extent of “core fox habitat”. So far over 470 K ha has been monitored (about a third of core fox habitat) and no positive detection has occurred.
2. Secondly, an extensive sampling program for predator scats carried out across eastern Tasmania was completed recently. DNA from the scats will be determined to identify the predator and its prey items as part of an inter-connected series of studies which include determining whether fox is detected. Processing of these scats in the laboratory is likely to take some months. (posters on this work are being presented at the Society conference: see Campbell et al. and Modave et al. in the conference list of presentations).
3. The third approach is mathematical modelling (Spread Model and Detection) using a Bayesian approach to produce an extinction probability curve for the incursion. Naturally the data set is small but preliminary indications support our hope (Caley and Barry, 2014) about fox status.
· The Department is embarking on stage 3 of the fox program which has field monitoring as a major component of its effort. We are also committed to developing a long term strategy for future fox incursions in the State. The work detailed above will clearly contribute to the first decision point in developing a decision management framework that guides how effort and resources are best divided (e.g. surveillance, monitoring, quarantine) in the future.
· Gonçalves et al. published a letter in Forensic Science International Genetics regarding the issue of false negatives and false positives and a response has been submitted to the same journal (Sarre, McDonald, Berry, Barclay, Saunders and Ramsey).
Caley, P. And Berry, S.C. (2014) Quantifying extinction probabilities from sighting records: inference and uncertainties. PLoS ONE 9(4):e95857.doi:10.1371/journal.pone.0095857
Gonçalves, J., Marks, C.A., Obendorf, D., and Pereira, A.F.F. (2014) The risks of using “species-specific” PCR assays in wildlife research: The case of red fox (Vulpes vulpes) identification in Tasmania. Forensic Science International Genetics. 2014:e1-e3.
Sarre, S.D., McDonald, A.J., Berry, O.F., Barclay, C., Saunders, G.R. and Ramsey, D.S.L. (submitted) Defining specificity in DNA detection of wildlife: Response to Gonçalves et al. “The risks of using “species-specific” PCR assays in wildlife research: The case of red fox (Vulpes vulpes) identification in Tasmania. submitted to Forensic Science International Genetics.
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