Interspecific Competition and Niche Differentiation Between Plantago Lanceolata and Anthoxanthum Odoratum in a Natural Hayfield

Abstract

(1) A removal experiment was carried out to investigate whether intraspecific competition, interspecific competition and niche differentiation occurred within and between populations of Anthoxanthum odoratum and Plantago lanceolata in a natural hayfield. By removal of other plant species, plots were created in which each species occurred alone at different densities or with the second species. (2) There was strong intraspecific competition within the populations of both species at the densities in which they occurred. In mixed plots Anthoxanthum odoratum was less negatively influenced by interspecific competition than by competition with other A. odoratum individuals, and Plantago lanceolata was not affected by interspecific competition with Anthoxanthum odoratum. (3) The relative yield total (the sum of yields per species in mixed culture divided by yields in monoculture) reached values of about 1.5, which indicated a high degree of niche differentiation. During the 2 years of observation an equilibrium between the two species was established. (4) In undisturbed vegetation, the biomass of Plantago lanceolata decreased greatly after the addition of nutrients. In plots from which other plant species had been removed, fertilization led to an increase in P. lanceolata biomass. Decline of P. lanceolata (and probably of other dicotyledons) after fertilizer application may be caused by an increase in the intensity of interspecific competition.