This sediment deposition builds the river terraces and, as they are elevated, other plant species colonize resulting in further diversification in the floodplain community. Least Bell's vireo, along with willow flycatcher, yellow-breasted chat, yellow warbler, and many other species may continue to use this diverse community for another ten to twenty years. Gradually the canopy of the maturing willows and cottonwoods begins to shade out the diverse understory of vascular plants required by these birds. Older riparian gallery forest will continue to be used by western yellow-billed cuckoo, Cooper's hawk, warbling vireo and other species, but as the stand ages the diversity of the flora and fauna within the forest declines. Annual flooding and occasional large flood events maintain this cycle of succession and therefore maintains a mosaic of diverse natural communities.
Giant reed is native to Europe, and is found in freshwaters in the Mediterranean region.
Giant reed was purposefully introduced to California in the 1820's in the Los Angeles area as an erosion- control agent in drainage canals. Giant reed was also used as thatching for roofs of sheds, barns, and other buildings. Giant reed is a hydrophyte, growing along lakes, streams, drains and other wet sites. It uses prodigious amounts of water to supply its incredible rate of growth. Under optimal conditions giant reed can grow more than three inches per day.