An interesting article. But would it be pedantic of me to point out that in the before and after photos of Azolla control, it is either not the same place or not the same year? Look at the difference in the trees in the background.
I think the left hand photo is about 100 yards into the distance from the right one. Also, there appear to be piles of Azolla on the river bank in the left hand one. If so, the weevils were getting some outside help.
They are near enough the same location to see the same patch of river, the specific trees and effect. Whilst the camera station is not quite the same it is apparent they may be taken at different focal lengths - a different camera (or phone). Note the fence portion on the left.it appears too dramatic to be a month's difference but I know, to my cost, that willows grow almost as fast as Unidentified Invertebrates are added to https://www.ispotnature.org/communities/uk-and-ireland/view/project/770782/uk-invertebrates-without-id (Chus sayin')I agree, there seems to be some human intervention, though it is a remarkable 'demonstration'. Thanks @lavateraguy