Contour plot of Ammophila cover shows distinct species distributions across chronosequence ages and dune gradient.

Contours show areas of increasing cover across both gradients. Contours were created using predicted values of generalized linear models (see main text for details). Chronosequence ages were calculated for each quadrat using aerial photos and shoreline change rates (see main text for details). Dune gradient was calculated for each quadrat based on its standardized location along dune cross sections with the toe, crest, and heel at-1, 0, and 1, respectively. Each point on figure refers to the chronosequence age and dune gradient for an individual quadrat. Sites dominated by A. arenaria are shown in red, and those from A. breviligulata sites shown in blue.