Optimal movement strategies for social foragers in unpredictable environments
Authored by E J Milner-Gulland, Penelope A Hancock
Date Published: 2006
DOI: 10.1890/0012-9658(2006)87[2094:omsfsf]2.0.co;2
Sponsors:
Leverhulme Trust
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
Spatial movement models often base movement decision rules on
traditional optimal foraging theories, including ideal free distribution
(IFD) theory, more recently generalized as density-dependent habitat
selection (DDHS) theory, and the marginal value theorem (MVT). Thus
optimal patch departure times are predicted on the basis of the
density-dependent resource level in the patch. Recently, alternatives to
density as a habitat selection criterion, such as individual knowledge
of the resource distribution, conspecific attraction, and site fidelity, have been recognized as important influences on movement behavior in
environments with an uncertain resource distribution. For foraging
processes incorporating these influences, it is not clear whether simple
optimal foraging theories provide a reasonable approximation to animal
behavior or whether they may be misleading. This study compares patch
departure strategies predicted by DDHS theory and the MVT with
evolutionarily optimal patch departure strategies for a wide range of
foraging scenarios. The level of accuracy with which individuals can
navigate toward local food sources is varied, and individual tendency
for conspecific attraction or repulsion is optimized over a continuous
spectrum. We find that DDHS theory and the MVT accurately predict the
evolutionarily optimal patch departure strategy for foragers with high
navigational accuracy for a wide range of resource distributions. As
navigational accuracy is reduced, the patch departure strategy cannot be
accurately predicted by these theories for environments with a
heterogeneous resource distribution. In these situations, social forces
improve foraging success and have a strong influence on optimal patch
departure strategies, causing individuals to stay longer in patches than
the optimal foraging theories predict.
Tags
Individual-based model
Complexity
Heterogeneity
Marginal value theorem
information
Foraging behavior
Habitat selection
Spatial-distribution
Abundance
Serengeti grazers