PLANT COMPETITION EXPERIMENTS - TESTING HYPOTHESES AND ESTIMATING THEPROBABILITY OF COEXISTENCE

The analysis of plant competition experiments with variable plant dens ity is discussed based on three published data sets. It is shown how c onclusions regarding plant community dynamics from typical plant compe tition experiments can be extended and based on a statistical framewor k. The data are tested in hyperbolic competition models of decreasing complexity by a standard hierarchical statistical procedure. Hypothese s on the shape of the response surface curves, the number of necessary parameters, and the effects of competition on plant growth were teste d using maximum likelihood ratio tests. The conditions for coexistence in a hyperbolic competition model were examined analytically. Using t he found conditions for coexistence and Bayesian statistics, the proba bility of the four possible outcomes of two-species competition was es timated in a competition experiment with Avena fatua and A. barbata.