If the only point is that Dune was one of the first books where the ecology of planet was taken into account and where I played a major then that is interesting but more a bit of trivia then a major point in understanding the story. I have not read enough pre 1965 but I would argue that some early Heinlein works such Farmer in the Sky and Red Planet touched on it fairly heavily.

I think Larry grossly overstates the importance of ecology in the book and he goes so far as to call one of the first "ecological" SF novels” and mentions it predates Earth Day by five years. If Larry simply meant the scientific implications then he probably confused the issue by mentioning the first earth day which to me at least implies a environmentalism. The planet was not the central character is was simply the back drop in which the central story took place even if it was a well defined and well though out back drop.