ORCID Profile
0000-0002-8380-3612
Current Organisation
University of Adelaide
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Publisher: Wiley
Date: 30-05-2019
DOI: 10.1111/MAM.12157
Publisher: Oxford University Press (OUP)
Date: 2010
Publisher: The Company of Biologists
Date: 2018
DOI: 10.1242/JEB.184085
Abstract: Accelerometers are a valuable tool for studying animal behaviour and physiology where direct observation is unfeasible. However, giving biological meaning to multivariate acceleration data is challenging. Here, we describe a method that reliably classifies a large number of behaviours using tri-axial accelerometer data collected at the low s ling frequency of 1 Hz, using the dingo (Canis dingo) as an ex le. We used out-of-s le validation to compare the predictive performance of four commonly used classification models (Random Forest, k-Nearest Neighbour, Support Vector Machine, and Naïve Bayes). We tested the importance of predictor variable selection and moving window size for the classification of each behaviour and overall model performance. Random Forests produced the highest out-of-s le classification accuracy, with our best performing model predicting 14 behaviours with a mean accuracy of 87%. We also investigated the relationship between overall dynamic body acceleration (ODBA) and the activity level of each behaviour given its increasing use in ecophysiology as a proxy for energy expenditure. ODBA values for our four ‘high activity’ behaviours were significantly greater than all other behaviours, with an overall positive trend between ODBA and intensity of movement. We show that a Random Forest model of relatively low complexity can mitigate some major challenges associated with establishing meaningful ecological conclusions from acceleration data. Our approach has broad applicability to free-ranging terrestrial quadrupeds of comparable size. Our use of a low s ling frequency shows potential for deploying accelerometers over extended time periods, enabling capture of invaluable behavioural and physiological data across different ontogenies.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/WR13073
Abstract: Context Optimal management of invasive species should determine the interval between lethal-control operations that will sustain a desired population suppression at minimum cost. This requires an understanding of the species’ rate of recruitment following control. These data are difficult to acquire for vertebrate carnivores such as the red fox (Vulpes vulpes), which are not readily trapped or observed. Aims To provide a long-term evaluation of the effects of 1080 poison baiting on the abundance and extent of movement of red foxes in a semiarid environment. Methods We used non‐invasive DNA s ling of fox hairs in semi-arid Western Australia where the population was subject to two episodes of aerially delivered sodium fluoroacetate (1080) poison baits within 12 months. S ling took place at ~45-day intervals and in idual foxes were identified by genotyping eight microsatellite DNA markers and a gender-specific marker. Open-population and spatially explicit mark–recapture models were used to estimate the density, apparent survival and movements of foxes before and following baiting. Key results Following a severe reduction in density after baiting, fox density during the ensuing 12 months increased slowly (0.01 foxes km–2 month–1), such that density had only reached 22% of pre-baiting levels ~10 months after the initial baiting. Moreover, recovery was non‐linear as population growth was negligible for 6 months, then exhibited a nine-fold increase 7–9 months after control, coincident with the dispersal of juveniles in autumn. Fox movements between recaptures were on average 470% greater after baiting than before, in line with expectations for low-density populations, suggesting that the probability of encountering baits during this period would be higher than before baiting. Conclusions Baiting with 1080 poison significantly reduced the density of foxes, and the low density was sustained for more than 6 months. Foxes moved significantly further between recaptures after baiting when at low densities. Implications Control programs in this region may be carried out at low frequency to suppress fox density to a fraction of unbaited levels. The intensity of follow-up baiting may also be adjusted downwards, to take account of an increased probability of bait encounter in more mobile foxes.
Publisher: Hindawi Limited
Date: 20-09-2021
DOI: 10.1111/JZS.12418
Publisher: Springer Science and Business Media LLC
Date: 18-03-2021
DOI: 10.1186/S40462-021-00246-W
Abstract: Globally, arid regions are expanding and becoming hotter and drier with climate change. For medium and large bodied endotherms in the arid zone, the necessity to dissipate heat drives a range of adaptations, from behaviour to anatomy and physiology. Understanding how apex predators negotiate these landscapes and how they balance their energy is important as it may have broad impacts on ecosystem function. We used tri-axial accelerometry (ACC) and GPS data collected from free-ranging dingoes in central Australia to investigate their activity-specific energetics, and activity patterns through time and space. We classified dingo activity into stationary, walking, and running behaviours, and estimated daily energy expenditure via activity-specific time-energy budgets developed using energy expenditure data derived from the literature. We tested whether dingoes behaviourally thermoregulate by modelling ODBA as a function of ambient temperature during the day and night. We used traditional distance measurements (GPS) as well as fine-scale activity (ODBA) data to assess their daily movement patterns. We retrieved ACC and GPS data from seven dingoes. Their mass-specific daily energy expenditure was significantly lower in summer (288 kJ kg − 1 day − 1 ) than winter (495 kJ kg − 1 day − 1 p = 0.03). Overall, dingoes were much less active during summer where 91% of their day was spent stationary in contrast to just 46% during winter. There was a sharp decrease in ODBA with increasing ambient temperature during the day ( R 2 = 0.59), whereas ODBA increased with increasing T a at night ( R 2 = 0.39). Distance and ODBA were positively correlated ( R = 0.65) and produced similar crepuscular patterns of activity. Our results indicate that ambient temperature may drive the behaviour of dingoes. Seasonal differences of daily energy expenditure in free-ranging eutherian mammals have been found in several species, though this was the first time it has been observed in a wild canid. We conclude that the negative relationship between dingo activity (ODBA) and ambient temperature during the day implies that high heat gain from solar radiation may be a factor limiting diurnal dingo activity in an arid environment.
No related grants have been discovered for Jack Tatler.