New Paper on Tidal-flat Mapping Methodology Available Online

Dr. Nial Moores, Birds Korea, November 12th

It is clear that tidal-flat reclamation has led to massive declines in some species of shorebird (here in the ROK and at the population level). This is attested by our own research and of course by the must-read 2012 IUCN report on East Asian intertidal wetlands (which can still be accessed through

Much of the decline in shorebirds and other tidal-flat dependent waterbirds has been caused by tidal-flat reclamation, which leads to a loss of tidal-flat area and in many cases to increasing pressure and / or degradation of remaining areas. It has been known that the rate of loss of tidal-flats in the ROK and in the Yellow Sea has been high for several decades now. However, Birds Korea was the first NGO to provide an independent estimate of remaining tidal-flat in the ROK. As part of this, we provided (of course) a clear description of our methodology, and invited others to repeat our work. Our estimate (approximately 110,000ha of remaining tidal-flat at low tide, based on interpretation of online Daum images) was first published in the 2010 Birds Korea Blueprint, and was later expanded upon in one of the chapters of my doctoral thesis. The estimate was also incorporated (discretely!) into the 2012 IUCN report.

It seems, however, that this Birds Korea estimate has nonetheless still not been widely accepted by environmental groups, by universities or by decision-makers here in the ROK. Perhaps this is because our estimate is substantially less than half the 250,000ha of tidal-flat said to remain by leading development bodies and ministries, even as recently in 2012?

In March this year it was therefore very helpful to meet in Indonesia with researcher Nick Murray, from Professor Rich Fuller’s team at the University of Queensland. Using a different methodology, Nick Murray’s team has been mapping all remaining areas of tidal-flat in parts of East Asia. In an informal meeting, he suggested that based on Landsat imagery and his own methodology there were probably only 120,000ha or so of tidal-flat remaining in the ROK at lowest low tide (i.e. at least, their initial results were remarkably similar to our own estimate of tidal-flat at low tide).

Now, in the understanding, “that it’s better that this gets right out there and used by people rather than have it locked up in a subscription only journal” (Nick Murray, in lit. November 2012), the University of Queensland team have published details of their methodology in the open-access journal Remote Sensing, at:

The team would like to encourage wide distribution of this URL; and would also welcome hearing from researchers elsewhere who are interested in replicating the approach.

As stated in their abstract, their “method enables coastal morphology to be
mapped and monitored at continental scales, providing critical data to inform coastal adaptation measures for sea level rise, for monitoring coastal habitat loss and for developing ecosystem-based coastal conservation measures.”

This is the science. We now also need the political will to achieve genuine conservation of intertidal wetland – a nationally and globally important natural resource, depended upon both by birds and by people.

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