Environmental drivers of metapopulation dynamics throughout the full annual cycle in a declining Arctic-nesting migratory herbivore.

Abstract

Assessing the impacts of changing environmental conditions on animal species requires thorough understanding of population dynamics, which can be difficult to estimate when animals aggregate into spatially discrete subpopulations. We used 39 years of fecundity, capture-recapture and abundance data in an integrated metapopulation model to study environmental drivers of demography in a declining migratory bird, the Greenland white-fronted goose (Anser albifrons flavirostris). We found that low fecundity due to earlier spring vegetation phenology on staging areas and increased snow on breeding areas explained metapopulation decline, though the strength of these effects varied by subpopulation. Differential immigration and emigration rates affected local wintering abundance trends, highlighting the importance of quantifying subpopulation-metapopulation dynamics for understanding fragmented animal populations. We provide a framework for extending commonly used integrated population models to a metapopulation framework for testing novel ecological hypotheses about how changing environmental conditions within and among subpopulations drive changes in animal abundance.