Funded Grants

Migratory Networks: Exploring the dynamics of complex migration systems

There is a gap in theoretical population ecology. We lack theory and models that can be used to address the population dynamics and movements of animals that migrate seasonally. This is surprising because the spectacular phenomenon of migration has fascinated people for centuries and because migratory species, which are found within a wide range of taxa including birds, marine mammals, ungulates, and insects, comprise a large proportion of the earth’s biodiversity. Many migratory species, especially those that migrate long distances whether by land, air, or sea, are facing considerable threats from anthropogenic habitat loss and degradation, and from changes to the environment wrought by climate change. There is, therefore a pressing need to develop models and theory that can be used to understand the complex dynamics of migratory populations.

I propose that the ecology of migratory species can be studied by developing a new theoretical framework, Migratory Networks. Migratory networks consist of nodes representing habitat regions connected by the regular, seasonal movements of species. Migratory networks differ from other ecological networks in that nodes can be different functional habitat types (breeding and non-­‐breeding) and that each node is only occupied seasonally. As well as being important visualization tools, Migratory Networks are complex, nonlinear models that predict occupancy of nodes and strength of connections. These models will show how changes in phenology and alterations to quality and quantity of habitat patches along the migration route alter the connectivity of the network, the timing of migratory movements and population dynamics.

An important aspect of this research plan is the synergistic development of Migratory Network theory with its application to real-¬world species. I am currently working with collaborators to apply migratory network models to Tree Swallows, Wood Thrush, and Monarch Butterflies.

Migratory networks will be used to explore the effects of climate change, habitat loss, and infectious disease on the movements and population dynamics of migratory species. Migratory networks will also be used to examine theoretical hypotheses to explain patterns of migration, evolution of migration, and general effects of climate change. The application to real-­‐world migratory systems is intrinsically linked to the development of the theory itself as well as to the development of tools that will make the theory useful for conservation and policy.