 the curve.
Default = "lightblue".</p></dd>


<dt>alpha_mean</dt>
<dd><p>(numeric) alpha level for line representing the mean,
values from 0 to 1. Default = 0.7. Values close to 0 increase transparency.</p></dd>


<dt>alpha_CI</dt>
<dd><p>(numeric) alpha level for the region representing the
confidence interval. Default = 0.2.</p></dd>


<dt>xlab</dt>
<dd><p>(character) label for x-axis of plot. Default = "Number of
sites".</p></dd>


<dt>ylab</dt>
<dd><p>(character) label for y-axis of plot. Default = "Spe