Competition and zonation in an assemblage of ten species of marsh plants
(Keddy/Broussard)

This long term experimental study tests for competitive interactions, such as one-sided competition, along natural gradients. The shore of a newly-constructed pond was divided into parallel lanes along which are planted species such as saw grass, pickerelweed, arrow arum and maidencane. Gradients act like prisms, spreading biological communities into a spectrum, allowing us to measure plant responses to each other and to the environment. Competition could assemble the marsh species in different ways. Possibilities include: (1) Neutrality: the species coexist, (2) Détente: the species compete, but each takes a specified portion of the gradient or (3) Winner-take-all: one species eliminates the other.