Sketch of geographical location of the sampling stations (red dots in the insert) at the north-western part of the North Sea coast of the Dutch barrier island Schiermonnikoog.

<p>The stations indicated with ST1, ST2 and ST3 refer to the stations sampled in a previous study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063166#pone.0063166-Bolhuis1" target="_blank">[10]</a> to which the current dataset is compared. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063166#s2" target="_blank">Materials and Methods</a> for a description of the stations.