For non-migratory species, the increased risk for species extinction can often be directly compared to amount of habitat loss predicted for the species. For migratory species, however, the risk is compounded by not only habitat loss, but whether that habitat loss occurs at crucial locations along migratory routes. In their new paper, Iwamura and colleagues estimate how habitat loss will impact migratory shorebird populations that rely on the East Asian-Australasian Flyway using a novel application of graph theory. Their research combines analyses of available suitable habitat, sea-level rise projections and potential for habitat loss. The results show that taking into account loss of migratory connectivity greatly magnifies the impacts of habitat loss on shorebird populations. Sea level rise has the potential to eliminate critical breeding and resting grounds for migratory birds, and although it is possible that some species may shift migratory routes in response, the loss of habitat is shown to be have far greater potential consequences than simply the loss of suitable acreage. The decline of important intertidal habitat along critical flyways could greatly exacerbate population declines if sea levels rise as projected.
Iwamura, T., H. P. Possingham, I. Chades, C. Minton, N. J. Murray, D. I. Rogers, E. A. Treml, and R. A. Fuller, 2013. Migratory connectivity magnifies the consequences of habitat loss from sea-level rise for shorebird populations. Proceedings of the Royal Society B 280: 20130325.