Permanent plots as tools for plant community ecology

Abstract

Abstract. Permanent plots provide information on spatio‐temporal patterns in plant communities, which could be analyzed to yield correlated changes in pairs of species and information on species replacements in space. The potential use of permanent plots to study underlying processes of interspecific interactions (namely competition) is discussed. Two examples (one simulated, using a cellular automaton model, and one from a removal experiment in grasslands) are used to demonstrate that this use is not straightforward, since (1) radically different underlying mechanisms (symmetric founder control with little competitive replacement vs. asymmetric dominance control strongly structured by competition) may produce very similar spatio‐temporal patterns; and (2) topology of species replacements in space may be very different from the competitive hierarchy as determined by the removal experiment.Permanent plot data can be used to study interspecific interactions in the following ways: (1) if there is additional information to decide which of the potential underlying models is acceptable, permanent plot data may enable further articulation of the model, such as estimation of the model parameters; this approach is similar to that used in many other plant ecology fields (fine scale patterns, chronosequences, plant size distribution and dynamics); (2) data from permanent plots constrain the number of feasible underlying models; (3) permanent plot data provide verification of predictions of experimental studies; in this respect, they are much superior to non‐repeated studies of pattern.