Here's why:

* "Marsh community" is broad: Marshes can be freshwater, saltwater, or brackish. Each type has different dominant species.

* "Least plentiful" is relative: It depends on what you're comparing. Are we talking about individual species, specific groups of organisms (like insects vs. mammals), or overall biomass?

To help me answer your question, please provide more detail about:

* The type of marsh: Is it freshwater, saltwater, or brackish?

* What are you comparing: Individual species, groups of organisms, or total biomass?

Once I have this information, I can give you a better answer!