Marine nature parks need an icon of their own

As of now, nature parks/reserves have an icon that's some kind of tree. Which is good. But, when it's a marine reserve it looks a bit silly with a tree on water.

You need a specific icon for marine reserves. I realize that might mean some tweaking of your algorithms so that it senses when it's a case of nature reserve+water cover.

No files or tests are named. Start by locating the nature park/reserve icon selection and the handling of water cover, then identify how icons are defined in the set. Done means marine reserves use a dedicated marine icon while non-marine nature parks retain the existing tree icon.

Written by the indexing model from the issue text.