NTR: freshwater stream biome

[turbomam]

would be a sibling of ENVO:01000253 freshwater river biome

• Subclass of
  • freshwater biome
  • has part some freshwater stream (but will probably have to create that too)

[turbomam]

cc @aclum

[pbuttigieg]

Rivers are subclasses of streams, so the biome hierarchy should mirror that.

To be in pattern, we'll need a freshwater ecosystem class that can reach its successional climax state too.