Do mangrove trees have any mutualistic relationships?please help

One type of mutualistic relationship is one in which a
species is called a "keystone mutualist."  Mangrove trees qualify as keystone
mutualists.

A keystone mutualist is a species whose
existence is pretty much necessary for a whole ecosystem to exist.  If the keystone
mutualist is removed, the whole ecosystem collapses.  Not too surprisingly, mangroves
are a keystone mutualist in the mangrove swamp
ecosystem.

Mangrove swamps are large areas where pretty
much the only vegetation is mangroves.  The mangroves' roots sink down into the mud and
stabilize it.  When the mangroves do this, the muddy swamp and the mangroves' roots
become a habitat for many other creatures.  All of these depend on the
mangroves.

To read more, search for "red mangrove" in the
page that I have linked to.