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Putting the behavior into animal movement modeling: improved activity budgets from use of ancillary tag information


Bestley, S and Jonsen, I and Harcourt, RG and Hindell, MA and Gales, NJ, Putting the behavior into animal movement modeling: improved activity budgets from use of ancillary tag information, Ecology and Evolution, 6, (22) pp. 8243-8255. ISSN 2045-7758 (2016) [Refereed Article]


Copyright Statement

2016 The Authors. Ecology and Evolution. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1002/ece3.2530


Animal movement research relies on biotelemetry, and telemetry-based locations are increasingly augmented with ancillary information. This presents an underutilized opportunity to enhance movement process models. Given tags designed to record specific behaviors, efforts are increasing to update movement models beyond reliance solely upon horizontal movement information to improve inference of space use and activity budgets. We present two state-space models adapted to incorporate ancillary data to inform three discrete movement states: directed, resident, and an activity state. These were developed for two case studies: (1) a "haulout" model for Weddell seals, and (2) an "activity" model for Antarctic fur seals which intersperse periods of diving activity and inactivity. The methodology is easily implementable with any ancillary data that can be expressed as a proportion (or binary) indicator. A comparison of the models augmented with ancillary information and unaugmented models confirmed that many behavioral states appeared mischaracterized in the latter. Important changes in subsequent activity budgets occurred. Haulout accounted for 0.17 of the overall Weddell seal time budget, with the estimated proportion of time spent in a resident state reduced from a posterior median of 0.69 (0.650.73; 95% HPDI) to 0.54 (0.500.58 HPDI). The drop was more dramatic in the Antarctic fur seal case, from 0.57 (0.520.63 HPDI) to 0.22 (0.200.25 HPDI), with 0.35 (0.310.39 HPDI) of time spent in the inactive (nondiving) state. These findings reinforce previously raised contentions about the drawbacks of behavioral states inferred solely from horizontal movements. Our findings have implications for assessing habitat requirements; estimating energetics and consumption; and management efforts such as mitigating fisheries interactions. Combining multiple sources of information within integrated frameworks should improve inference of relationships between movement decisions and fitness, the interplay between resource and habitat dependencies, and their changes at the population and landscape level.

Item Details

Item Type:Refereed Article
Keywords:ancillary information, animal movement, Antarctic seals, behavioral switching, foraging behavior, Integrated Marine Observing System, marine predators, satellite tracking, state-space model
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Bestley, S (Dr Sophie Bestley)
UTAS Author:Hindell, MA (Professor Mark Hindell)
ID Code:112154
Year Published:2016
Web of Science® Times Cited:5
Deposited By:Ecology and Biodiversity
Deposited On:2016-10-28
Last Modified:2018-04-18
Downloads:139 View Download Statistics

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