Seasonal Animal Migrations and the Arctic: Ecology, Diversity, and Spread of Infectious Agents

Abstract

Many animals are highly mobile and have evolved long-distance migrations that make them actors in multiple ecosystems through the year and throughout their life. Most long-distance migrations are adaptations to seasonality and more generally to spatio-temporal patterns in food availability, weather, risk of parasite and pathogen infections, and predation risk. Due to the considerable seasonality in high-latitude environments, with Arctic as extremes, long-distance seasonal migrations are a distinct characteristic of the fauna in these Northern regions. The Arctic is also a seasonal melting pot during the productive summer, when large numbers of organism move in from all over the world. Travelling animals connect ecosystems and serve as spatial vectors, of energy and nutrients and of other organisms that follow (sometimes as active hitchhikers) for parts or the entire route. We provide an overview of central concepts and main spatial and temporal (phenology) patterns of animal migrations, with a focus on migrations to and from as well as within northern regions (i.e. arctic and sub-arctic regions). In particular, we characterize the role of migratory animals as vectors and hosts for infectious agents, and we discuss the concepts of migratory escape, migratory culling, and migratory separation. Understanding drivers and patterns of migrations is essential for understanding the dynamics of diseases and must therefore be considered in veterinary and human medicine and the One Health perspective. We show how climate change and human stressors impact migrations and how these changes may interact with the animals’ capacity to transport parasites and other infectious agents. Throughout, we stress the evolutionary ecology of migrations, a plastic trait under natural selection with complex ecological consequences.