Graphics acknowledgments:

As always, the animal pictures were drawn by Ursula Hilsdorf.

The ship icon is free for non-commercial use.  Source:
  http://www.iconarchive.com/show/transport-icons-by-aha-soft/sailing-ship-icon.html
  
Terrain icons are from the open-source game "Dungeon Crawl Stone Soup", and are
available under a modified Nethack license. Source:
   http://crawl.develz.org/wordpress/
   
The naturalist icon is based on an illustration from:   
   We Were There With Charles Darwin on H.M.S. Beagle (We Were There books, 30) - Hardcover (1960) by Philip Eisenberg, Professor Clude K. Kluckhohn, and H. B. Vestal
 
Free-as-in-beer palm tree image from:
   http://www.psdgraphics.com/icons/palm-tree-psd-web-icon/