Clementsian adjective 2noun 1forms 3 adjective2 •Of or relating to Frederic Clements (1874-1945), American plant ecologist and pioneer in the study of vegetation succession. •Adhering to an ecological model that emphasizes an orderly progression of species as an ecosystem matures.Tobey (1981) traced the rise and presumed fall of Clementsian ecology in grassland ecology. — 1986 noun1 •One who follows the ideology of Frederic Clements.We are not surprised to learn that Britain's leading Clementsian was a philosopher by temperament. — 1981 formsClementsians · more Clementsian · most Clementsian