Analysis of temporal patterns in animal movement networks

Abstract

1. Understanding how animal movements change across space and time is a fundamental question in ecology. While classical analyses of trajectories give insightful descriptors of spatial patterns, a satisfying method for assessing the temporal succession of such patterns is lacking.2. Network analyses are increasingly used to capture properties of complex animal trajectories in simple graphical metrics. Here, building on this approach, we introduce a method that incorporates time into movement network analyses based on temporal sequences of network motifs.3. We illustrate our method using four example trajectories (bumblebee, black kite, roe deer, wolf) collected with different technologies (harmonic radar, platform terminal transmitter, global positioning system). First, we transformed each trajectory into a spatial network by defining the animal's coordinates as nodes and movements in between as edges. Second, we extracted temporal sequences of network motifs from each movement network and compare the resulting behavioural profiles to topological features of the original trajectory. Finally, we compared each sequence of motifs with simulated Brownian and Lévy random motions to statistically determine differences between trajectories and classical movement models. 4. Our analysis of the temporal sequences of network motifs in individual movement networks revealed successions of spatial patterns corresponding to changes in behavioural modes that can be attributed to specific spatio-temporal events of each animal trajectory. Future applications of our method to multi-layered movement and social network analysis yield considerable promises for extending the study of complex movement patterns at the population level.

Animal social networks: Towards an integrative framework embedding social interactions, space and time

“…As a result, space use represents an important dimension for many social processes, such as disease spread (Albery et al, 2020). A particular focus of this joint Special Feature is on the study of how habitat constraints or spatial ecology can shape group social structure through individual movements (Albery et al, 2020; Milner et al, 2020; Pasquaretta et al, 2020).…”

“…Such a multivariate approach is of considerable interest to understand the relative influence of habitat structure and/or social factors in shaping social structure and to better understand their dynamics, host pathogen dynamics, or species–species assemblages (Massol et al, 2020). The new methods presented in this joint Special Feature (Albery et al, 2020; Massol et al, 2020; Milner et al, 2020; Pasquaretta et al, 2020) will help better understand such complex related processes.…”

“…habitat heterogeneity, entropic disturbances) affect social behaviour, group‐level dynamics and population‐level social structure? For example, climatic factors that shape habitats through plant phenology and resource dispersion may affect animal social structure and habitat use (Albery et al, 2020; Brandell et al, 2020; Burns et al, 2020; Gilbertson et al, 2020; Milner et al, 2020; Pasquaretta et al, 2020). (2) Which, how and why behavioural or physiological factors (e.g.…”

The role of habitat configuration in shaping animal population processes: a framework to generate quantitative predictions

“…Animal movement networks characterize the observed movements of animals, with nodes anchored in physical landscapes and links quantifying the movement flows of animals among them (Pasquaretta et al, 2020). The resulting functional connectivity then aims to describe the extent to which habitats facilitates or impedes movements (Taylor et al, 1993;Goodwin and Fahrig, 2002).…”

“…Therefore, animal habitat networks ( Fig. 2) are distinct from movement networks (Box 1), where links characterize the actual movements of animals among habitat components (Jacoby and Freeman, 2016;Pasquaretta et al, 2020).…”