What’s true about facilitation model of succession?
The facilitation model proposes that early colonists make an initially harsh environment more suitable for species that arrive later. Pioneers may stabilize substrate, weather rock, add organic matter or nitrogen, retain water, moderate temperature, reduce wind, or provide shade. These changes allow successors to germinate and survive where they previously could not. Later species may then outcompete, overtop, or otherwise replace the pioneers, so helping successors does not imply that early species persist indefinitely. This differs from tolerance, in which later species can establish without
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20