Notes from a research seminar on the decimation of migratory shorebird species on the East Asian Flyway

G’day I attended a lunchtime seminar presented by Peter Fuller (UQ) today on the ongoing decline of the number of migratory waders reaching Australia. Peter is part of a group studying wader dynamics over the last couple of decades. While the abundance of non-magratory shorebirds has been stable, most transhemispherical migrants are declining at annual rates of 4 to 9%. Curlew Sandpipers are one of the hardest hit species, with their numbers down 84% over 25 years. The common factor in the decline for most species is the loss of habitat in the Yellow sea (basically two thirds in recent decades (there is a recent article on the subject at http://www.wantchinatimes.com/news-subclass-cnt.aspx?id=20141027000048&cid=1105 ). Peter noted that 90% of the variance in the rate of decline of the various species studies was linked to the dependence of those species on the Yellow Sea as a transit point for their migrations. About half of the inter-tidal habitat loss was due to land use changes (15% aquaculture, 25% agriculture, 10% industrial). The other 50% was due to coastal erosion – a combination of sea level rise and reduced sediment deposition (due to the presence of dams etc). The long term survival of the impacted migratory species may depend on how they can adjust their migrations to get around the loss of their transit points. Peter noted that there had been changes in Ruff migration routes in response to habitat issues. Two research questions that occurred to me were: 1. How are the size and age structure of the overwintering populations of the migratory species changing? 2. Are the patterns of vagrancy changing? Do they presage possible changes in migratory behaviour? Ultimately, there is the fundamental question of evolutionary plasticity – will the shorebirds be able to change enough to survive the changes in the world? Regards, Laurie.


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