Hierarchical, Memory-Based Movement Models for Translocated Elk (Cervus canadensis)

Andrea Falcón-Cortés,Juan Manuel Morales,Denis Boyer,Evelyn Merrill,Jacqueline L Frair

doi:10.3389/fevo.2021.702925

Abstract

The use of spatial memory is well-documented in many animal species and has been shown to be critical for the emergence of spatial learning. Adaptive behaviors based on learning can emerge thanks to an interdependence between the acquisition of information over time and movement decisions. The study of how spatio-ecological knowledge is constructed throughout the life of an individual has not been carried out in a quantitative and comprehensive way, hindered by the lack of knowledge of the information an animal already has of its environment at the time monitoring begins. Identifying how animals use memory to make beneficial decisions is fundamental to developing a general theory of animal movement and space use. Here we propose several mobility models based on memory and perform hierarchical Bayesian inference on 11-month trajectories of 21 elk after they were released in a completely new environment. Almost all the observed animals exhibited preferential returns to previously visited patches, such that memory and random exploration phases occurred. Memory decay was mild or negligible over the study period. The fact that individual elk rapidly become used to a relatively small number of patches was consistent with the hypothesis that they seek places with predictable resources and reduced mortality risks such as predation.

Highlights

The use of spatial memory is well-documented in many animal species
A memory-based movement model similar to the ones that we propose below was fitted to roe deer reintroduced into a novel environment, showing that home ranges in the absence of territoriality could emerge from the benefits of using memory during foraging (Ranc et al, 2020)
Considering the Posterior Predictive Check (PPC) for all individuals and models (Supplementary Figure 9), we found that six trajectories were contained within the 95% credible interval (CI) of Model I, while 17 did so for Model II, 10 for Model III and 15 for Model IV

Summary

Introduction

Humans, nonhuman primates and other large-brained vertebrates make movement decisions based on spatial representations of their environments (Wills et al, 2010) These representations may allow animals to move directly to important sites in their environment that lie outside of their perceptual range (Normand and Boesch, 2009; Presotto and Izar, 2010), such as resource patches, sites that connect with other high quality sites in space, or safe spots to avoid predators, and may allow them to estimate the travel cost to reach a particular place (Lanner, 1996; Janson, 2007; Janson and Byrne, 2007; Noser and Byrne, 2007). Identifying how animals use memory to make decisions is fundamental to developing a general theory of animal movement and space use (Gautestad and Mysterud, 2005; Morales et al, 2010; Spencer, 2012)

Methods

Results

Conclusion