"You may remember me talking about Floristic Quality Assessment, which assigns an ecological number from 0-10 for each species according to the habitat stage they usually occur in, from early to late successional. I ran the numbers on the Bellevue survey and got an FQA value of 20.6, which is on the high side, indicating a stable species rich environment. This is probably a case of these species having been present all along in low numbers building up a seedbank. This allowed them to dominate the habitat, eliminating the possibility of an early successional phase." (07/24/18)