Grant: Discovery Grants Program - Individual

Local movement and long-distance dispersal (LDD) influence many important ecological processes. However, progress in understanding animal movement has been hampered by the lack of an integrative modelling framework for guiding the collection and interpretation of empirical data and providing adequate fits to them. Recent work has shown that in many cases Lévy-stable motions (LSM), a class of random-walk models, are a powerful alternative to classic diffusion models. LSM also have desirable mathematical properties and have close connections with foraging theory, which shows that under many conditions LSM provide an optimal search strategy. These attributes make LSM an appealing conceptual framework for studying movement. The general objective of the proposed research is to test the usefulness of the LSM model for characterizing individual movement behaviours and linking individual variation in movement to population-level patterns in the field. The central hypotheses to be tested are that: (i) leptokurtosis and heavy tails in dispersal kernels can be accounted for without invoking effects of intrapopulation or environmental heterogeneity, (ii) small-scale movement of individuals can be extrapolated to predict population-level redistribution and LDD at larger spatial and temporal scales, and (iii) individual movement behaviour is consistent with an optimal search strategy for intermittent foragers. Stream fish will be used as a study system because their movement can be conveniently modeled along a single spatial dimension. The proposed research will provide rigorous field tests of the LSM model's ability to connect local movements to LDD, project from short-term individual behaviour to population spread, and generate insight on searching behaviour and population heterogeneity in stream fish. Demonstration of improved performance relative to current models should encourage the application of the LSM model to other organisms and environmental contexts, including its use as a management tool for evaluating the role of LDD in population persistence, access to critical habitats, colonization by invasive species, and the spread of disease.