B1428
Title: Incorporating body condition into the analysis of animal movement
Authors: Marco Antonio Gallegos Herrada - University of Toronto (Canada) [presenting]
Vianey Leos Barajas - University of Toronto (Canada)
Juan Morales - University of Glasgow (United Kingdom)
Abstract: A long-sought goal in ecology is to connect movement with population dynamics. Especially for ungulates, there is a known link between conditions (e.g. fat reserves) and the probability of survival and reproduction. Assuming a particular genetic makeup and physiology, the condition reflects the history of behavioural decisions, including movement and habitat use. However, the condition of an animal can also have a direct implication on the types of movements that it performs and the habitats that it visits. Using Merino sheep as a case study, we present a model that allows for the interaction of movement and condition over time. For the movement dynamics, we use discrete-time, finite-state hidden Markov models (HMMs), with the positional data of the sheep serving as the observation process and the underlying state process serving as a proxy for behaviors of interest. To incorporate condition as a potential covariate affecting the movement, and thus behavioral, process, we make use of physiological equations that describe the evolution of body fat in order to predict daily values of the condition process, which are typically recorded once a month. The physiological equations are expressed as a function of the states inferred by HMM, as well as the distance that the sheep travels.
