title: Plotting ordiellipse function from vegan package onto NMDS plot created in ggplot2
body: <p>Instead of the normal plot function I am using <code>ggplot2</code> to create NMDS plots.  I would like to display groups in the NMDS plot using the function <code>ordiellipse()</code> from the <code>vegan</code> package. </p>
  
  <p>Example data:</p>
  
  <pre><code>library(vegan)
  library(ggplot2)
  data(dune)
  # calculate distance for NMDS
  sol &lt;- metaMDS(dune)
  # Create meta data for grouping
  MyMeta = data.frame(
    sites = c(2,13,4,16,6,1,8,5,17,15,10,11,9,18,3,20,14,19,12,7),
    amt = c("hi", "hi", "hi", "md", "lo", "hi", "hi", "lo", "md", "md", "lo", 
            "lo", "hi", "lo", "hi", "md", "md", "lo", "hi", "lo"),
    row.names = "sites")
  # plot NMDS using basic plot function and color points by "amt" from MyMeta
  plot(sol$points, col = MyMeta$amt)
  # draw dispersion ellipses around data points
  ordiellipse(sol, MyMeta$amt, display = "sites", kind = "sd", label = T)
  
  # same in ggplot2
  NMDS = data.frame(MDS1 = sol$points[,1], MDS2 = sol$points[,2])
  ggplot(data = NMDS, aes(MDS1, MDS2)) + 
    geom_point(aes(data = MyMeta, color = MyMeta$amt))
  </code></pre>
  
  <p>How can I add ordiellipse to the NMDS plot created with <code>ggplot2</code>?</p>
  
  <p>Didzis Elferts' answer below works great.  Thank you!  However, I am now interested in plotting the following ordiellipse to the NMDS plot created with <code>ggplot2</code>:</p>
  
  <p><code>ordiellipse(sol, MyMeta$amt, display = "sites", kind = "se", conf = 0.95, label = T)</code></p>
  
  <p>Unfortunately, I don't understand enough about how the <code>veganCovEllipse</code> function works to be able to adjust the script myself. </p>