Context-dependent perceptual ranges and their relevance to animal movements in landscapes

Authors


Jeremy D. Olden, Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado 80523, USA. E-mail: olden@lamar.colostate.edu

Summary

  • 1An animal's perceptual range defines the spatial extent of the landscape for which information is available to make movement decisions. Ecologists studying and modelling animal dispersal have commonly assumed that individual movements arise from a predefined set of local decision rules operating within a static isotropic (i.e. circular) perceptual range.
  • 2We discuss how this assumption fails to recognize the potential for plasticity in perceptual ranges and present a conceptual model that illustrates how anisotropic perceptual ranges can arise from animal orientation to environmental stimuli.
  • 3Using model simulations we show how perceptual distance (i.e. greatest Euclidean distance at which habitat patches can be perceived), horizon (i.e. panoramic view or angular degrees of the landscape perceived) and breadth (i.e. areal extent of the landscape perceived), change as a function of increased strength of a hypothetical stimuli.
  • 4Our results show that anisotropic perceptual ranges can differ substantially from traditional, isotropic perceptual ranges in all three aspects depending on the strength of the stimuli and nature in which it interacts with other elements of the landscape.
  • 5We highlight the implications of these findings for modelling animal movements in ecological landscapes with the hope that context-dependent perceptual ranges are considered in future studies.

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