Hidden Markov models: the best models for forager movements?

PLoS One. 2013 Aug 23;8(8):e71246. doi: 10.1371/journal.pone.0071246. eCollection 2013.

Abstract

One major challenge in the emerging field of movement ecology is the inference of behavioural modes from movement patterns. This has been mainly addressed through Hidden Markov models (HMMs). We propose here to evaluate two sets of alternative and state-of-the-art modelling approaches. First, we consider hidden semi-Markov models (HSMMs). They may better represent the behavioural dynamics of foragers since they explicitly model the duration of the behavioural modes. Second, we consider discriminative models which state the inference of behavioural modes as a classification issue, and may take better advantage of multivariate and non linear combinations of movement pattern descriptors. For this work, we use a dataset of >200 trips from human foragers, Peruvian fishermen targeting anchovy. Their movements were recorded through a Vessel Monitoring System (∼1 record per hour), while their behavioural modes (fishing, searching and cruising) were reported by on-board observers. We compare the efficiency of hidden Markov, hidden semi-Markov, and three discriminative models (random forests, artificial neural networks and support vector machines) for inferring the fishermen behavioural modes, using a cross-validation procedure. HSMMs show the highest accuracy (80%), significantly outperforming HMMs and discriminative models. Simulations show that data with higher temporal resolution, HSMMs reach nearly 100% of accuracy. Our results demonstrate to what extent the sequential nature of movement is critical for accurately inferring behavioural modes from a trajectory and we strongly recommend the use of HSMMs for such purpose. In addition, this work opens perspectives on the use of hybrid HSMM-discriminative models, where a discriminative setting for the observation process of HSMMs could greatly improve inference performance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Appetitive Behavior*
  • Computer Simulation
  • Fisheries
  • Humans
  • Markov Chains*
  • Models, Biological*
  • Motor Activity
  • Neural Networks, Computer
  • Peru
  • Ships
  • Support Vector Machine
  • Travel

Grants and funding

This work was supported by and is a contribution to the ANR project TOPINEME (TOp Predators as INdicators of Exploited Marine Ecosystem dynamics) and the International Joint Laboratory DISCOH (DInámicas del Sistema de la COrriente de Humboldt).R. Joo was financially supported by an ARTS grant from IRD and managed by Campus France.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.