Explaining and predicting animal migration under global change

Many migratory species are declining due to global environmental change.
Yet, their complex annual cycles make unravelling the impacts of potential
drivers such as climate and land-use change on migrations a major
challenge. Identifying where, when, and how threatening processes impact
species’ migratory journeys and population dynamics is crucial for
identifying effective conservation actions. Here, we describe how a new
migration modelling framework – Spatially-explicit Adaptive Migration
Models (SAMMs) – can simulate the optimal behavioural decisions required
to migrate across open land- or seascapes varying in character over space
and time, without requiring predefined behavioural rules. Models of
adaptive behaviour have been used widely in theoretical ecology but have
great untapped potential in real-world contexts. Applying adaptive
behaviour models across open environments will allow users to explore
flexibility in how migratory strategies respond to environmental change
and the consequences of migrants not being able to adapt to change. We
outline how SAMMs can be used to model migratory journeys through aerial,
terrestrial, and aquatic environments, demonstrating their potential using
a case study on the common cuckoo (Cuculus canorus) and comparing modelled
to observed behaviours. SAMMs offer a tool to identify the key threats
faced by migratory species and to predict how they will adapt to future
migratory journeys in response to changing environmental conditions.